The chemistry of new nitrosyltungsten complexes with pyridyl- functionalized phosphane ligands

Article abstract of DOI:10.1002/1099-0682(200007)2000:7<1411::AID-EJIC1411>3.0.CO;2-M

The coordination chemistry of pyridylphosphanes, such as 2(6-tert- butylpyridyl)diphenylphosphane (Ph₂P-tert-Bupy) (6) and 2-(6-tert- butylpyridyl)dimethylphosphane (Me₂P-tert-Bupy) (7) towards a number of nitrosyltungsten complexes is reported. Displacement of the loosely coordinated MeCN from [W(CH₃CN)₃(CO)₂(NO)][BF₄] led to the following cationic compounds incorporating mono- and bidentate coordinated phosphane ligands: cis,cis-[W(CO)₂(NO)(Ph₂PR)(η²-Ph₂PR)][BF₄], [R = 2-pyridyl (9a), 2-picolyl (11)], cis,cis-[W(CO)(NO)(η²-Ph₂Ppy)₂][BF₄] (20), trans,trans-[W(CO)(NO)(η²-Ph₂Ppy)₂][BPh₄] (21), fac-[W(CO)₂(NO) (Me₂P- py)₃][BF₄] (16), fac-[W(CO)₂(NO)(Me₂P-tert-Bupy)₃][BF₄] (18), cis,cis- [W(CO)₂(NO)(Me₂Ppy)(η₂-Me₂Ppy)][BF₄] (22), and cis,cis- [W(CO)₂(CH₃CN)(NO)(Me₂P-tert-Bupy)₂][BF₄] (23a). The cationic complex cis,mer-[W(CO)₃(NO)(Ph₂P-tert-Bupy)₂][PF₆] (14) has been prepared by nitrosylation of cis/trans-W(CO)₄(Ph₂P-tert-Bupy)₂ (13). Reactions of 9a, 11, 14, 16, and 18 with hydride transfer reagents afforded trans,- trans- HW(CO)₂(NO)(Ph₂Ppy)₂ (10), trans, trans-HW(CO)₂(NO)(Ph₂Ppic)₂ (12), trans, trans-HW(CO)₂(NO)(Ph₂-tBupy)₂ (15), cis/trans- HW(CO)₂(NO)(Me₂Ppy)₂ (17), and cis/trans-HW(CO)₂(NO)(Me₂P-tert-Bupy)₂ (19), respectively. Reactivity experiments with acetic acid, hydroiodic acid, carbon dioxide, and acetylenedicarboxylic acid were performed, and were found to afford trans-W(CO)(NO)(Ph₂Ppy)₂(η²-CH₃CO₂) (24), trans, trans- IW(CO)₂(NO)(Ph₂Ppy)₂ (25), trans-W(HCO₂)(CO)₂(NO)(Ph₂Ppy)₂ (26), and trans-W{η²-(Z)C(CO₂Me)=CH[C(O)OMe]}(CO)(NO)(Ph₂Ppic)₂ (27), respectively. The influence of the pyridyl substituent in 10 was probed by a comparative H/D exchange experiment in which 10 and the analogous complex HW(CO)₂(NO)(PPh₃)₂ were treated with MeOD. The deuterated complex trans,trans-WD(CO)₂(NO)(Ph₂Ppy)₂ (28) could be isolated. The structures of 9a, 11, 14, and 20 have been determined by single-crystal X-ray diffraction analysis.

Full text of DOI:10.1002/1099-0682(200007)2000:7<1411::AID-EJIC1411>3.0.CO;2-M

FULL PAPER
The Chemistry of New Nitrosyltungsten Complexes with Pyridyl-
Functionalized Phosphane Ligands
Jürgen Baur,[a] Heiko Jacobsen,[a] Peter Burger,[a] Georg Artus,[a] Heinz Berke,*[a] and
Lutz Dahlenburg[b]
Keywords: Tungsten / Hydride complexes / P ligands / N ligands / Chelates / Ligand dynamics
The coordination chemistry of pyridylphosphanes, such as 2-
(6-tert-butylpyridyl)diphenylphosphane (Ph2P-tert-Bupy) (6)
and 2-(6-tert-butylpyridyl)dimethylphosphane (Me2P-tert-
Bupy) (7) towards a number of nitrosyltungsten complexes is
reported. Displacement of the loosely coordinated MeCN
trans-HW(CO)2(NO)(Ph2Ppy)2 (10), trans,trans-HW(CO)2(N-
O)(Ph2Ppic)2 (12), trans,trans-HW(CO)2(NO)(Ph2-tBupy)2
(15), cis/trans-HW(CO)2(NO)(Me2Ppy)2 (17), and cis/trans-
HW(CO)2(NO)(Me2P-tert-Bupy)2 (19), respectively. Reactiv-
ity experiments with acetic acid, hydroiodic acid, carbon di-
from [W(CH3CN)3(CO)2(NO)][BF4] led to the following cat- oxide, and acetylenedicarboxylic acid were performed, and
ionic compounds incorporating mono- and bidentate coord- were found to afford trans-W(CO)(NO)(Ph2Ppy)2(η2-
inated phosphane ligands: cis,cis-[W(CO)2(NO)(Ph2PR)(η2- CH3CO2) (24), trans,trans-IW(CO)2(NO)(Ph2Ppy)2 (25), trans-
Ph2PR)][BF4], [R = 2-pyridyl (9a), 2-picolyl (11)], cis,cis-
W(HCO2)(CO)2(NO)(Ph2Ppy)2 (26), and trans-W{η2-(Z)-
C(CO2Me)=CH[C(O)OMe]}(CO)(NO)(Ph2Ppic)2 (27), re-
spectively. The influence of the pyridyl substituent in 10 was
[W(CO)(NO)(η2-Ph2Ppy)2][BF4] (20), trans,trans-[W(CO)-
(NO)(η2-Ph2Ppy)2][BPh4]
(21),
fac-[W(CO)2(NO)(Me2P-
py)3][BF4] (16), fac-[W(CO)2(NO)(Me2P-tert-Bupy)3][BF4] probed by a comparative H/D exchange experiment in which
(18), cis,cis-[W(CO)2(NO)(Me2Ppy)(η2-Me2Ppy)][BF4] (22),
and cis,cis-[W(CO)2(CH3CN)(NO)(Me2P-tert-Bupy)2][BF4]
(23a). The cationic complex cis,mer-[W(CO)3(NO)(Ph2P-tert-
Bupy)2][PF6] (14) has been prepared by nitrosylation of cis/
trans-W(CO)4(Ph2P-tert-Bupy)2 (13). Reactions of 9a, 11, 14,
16, and 18 with hydride transfer reagents afforded trans,-
10 and the analogous complex HW(CO)2(NO)(PPh3)2 were
treated with MeOD. The deuterated complex trans,trans-
WD(CO)2(NO)(Ph2Ppy)2 (28) could be isolated. The struc-
tures of 9a, 11, 14, and 20 have been determined by single-
crystal X-ray diffraction analysis.
Introduction
tion spheres. Similar investigations with P,N-, P,O-, and P,S-
hybrid ligands have been described previously.[13Ϫ15]
Previously, we have demonstrated that nitrosyltungsten
hydride complexes are efficient reducing agents for alde-
hydes and ketones, the best results being achieved in the
presence of a weak acid.[1Ϫ3] Furthermore, it has been
shown that OϪH and NϪH bonds can act as weak acid
components towards weakly basic MϪH bonds.[4Ϫ8] Thus,
intramolecular H H interactions may be established, which
could also play an important role in the heterolytic splitting
of dihydrogen.[9] The pyridylphosphane ligand offers the
possibility of either abstracting a proton from an external
source or of activating a dihydrogen ligand coordinated to
an unsaturated metal centre.[10] Therefore, this base-pro-
moted splitting of dihydrogen through formation of a
(ligandϪHϩ)Ϫ(metalϪHϪ) intermediate is of great signific-
ance with regard to catalytic ionic hydrogenations, as re-
cently described by Noyori.[11,12] In order to design such a
bifunctional system, we set out to prepare a series of cat-
ionic nitrosyltungsten and nitrosyltungsten hydride species
having basic pyridyl substituents present in their coordina-
Results and Discussion
Preparation of Pyridyl-Substituted Phosphane Ligands
Diphenylpyridylphosphane (Ph2Ppy)[16] and dimethylpyr-
idylphosphane (Me2Ppy)[17] were prepared according to lit-
erature procedures. On the other hand, new methods were
developed for the synthesis of phosphanes bearing bulkier
pyridyl substituents. Thus, the picolyl-substituted derivative
2-(6-methylpyridyl)diphenylphosphane (Ph2Ppic) was syn-
thesized by a route different from that reported in the liter-
ature[18] by adding 6-chloro-2-picoline to a solution of
LiPPh2, prepared from n-butyllithium and diphenylphos-
phane. For the preparation of the tert-butyl-substituted
phosphanes,
2-(6-tert-butylpyridyl)diphenylphosphane
(Ph2P-tert-Bupy) and 2-(6-tert-butylpyridyl)dimethylpho-
sphane (Me2P-tert-Bupy), the starting material 2-tert-butyl-
6-chloropyridine was synthesized according to a method
described by Mariella for analogous compounds.[19]
[a]
Anorganisch-chemisches Institut der Universität Zürich,
Winterthurerstrasse 190, 8057 Zürich, Switzerland
Fax: (internat.) ϩ 41-1/635-46802
E-mail: hberke@unizh.ch
Preparation of the Cationic Complexes
[b]
Institut für Anorganische Chemie der Friedrich-Alexander-
With the exception of the bulkiest phosphane, Ph2P-tert-
Bupy, the best yields of the cationic metal complexes were
Universität Erlangen-Nürnberg,
Egerlandstraße 1, 91058 Erlangen, Germany
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
1434Ϫ1948/00/0707Ϫ1411 $ 17.50ϩ.50/0
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H. Berke et al.
FULL PAPER
obtained by using [W(CH3CN)3(CO)2(NO)][BF4][20] as the
starting material. Thus, the addition of two equivalents of
Ph2Ppy or Ph2Ppic to [W(CH3CN)3(CO)2(NO)][BF4] in
dichloromethane resulted in substitution of the three ace-
tonitrile ligands by two phosphanes, one of which coordin-
ated in a monodentate fashion and the other in a bidentate
mode, thereby affording complexes 9a and 11, respectively
[Equation (1)]. Spectroscopic studies showed that no fur-
ther phosphane coordination occurred, even in the presence
of an excess of the ligand.
Figure 1. Energy profile for the pyridyl exchange reaction; the solid
line refers to the left ordinate axis, the dashed line to the right
ordinate axis
concerted fashion and one may envisage the exchange pro-
cess as follows. The N2 atom of the free pyridyl unit first
approaches the metal centre, which requires about two-
The variable-temperature (VT) NMR spectra of com- thirds of the energy of activation. Bond cleavage then oc-
pound 9a reveal dynamic behaviour. At room temperature, curs, and in the transition state the two N atoms are only
two broad resonances are observed in the 31P-NMR spec- weakly coordinated to the tungsten centre. The formerly
trum at δ ϭ 24.8 and δ ϭ Ϫ18.3, which sharpen into two bound pyridyl unit rotates away to relieve steric hindrance,
doublets below Ϫ15 °C. The energy of activation for the allowing formation of the bond between N2 and W. The
exchange process was estimated to be 57(2) kJ/mol by line- calculated activation energy of 62 kJ/mol is in good agree-
shape analysis. When the pyridyl groups in 9a are replaced ment with the experimentally determined value of 57(2) kJ/
by picolyl groups as in complex 11, no dynamic behaviour mol. This result can thus be taken as strong evidence in
is observed, even at 70 °C. In order to obtain more informa- favour of the suggested reaction mechanism.
tion regarding the mechanism of the pyridyl exchange pro-
Furthermore, it is noteworthy that the two pyridyl groups
cess, DFT calculations were performed on the model com- in complex 11 do not exchange. Taking the geometry of the
pound [W(CO)2(NO)(H2Ppy)(η2-H2Ppy)]ϩ. The energy transition state for 9, replacing the H atoms in the positions
profile of the exchange reaction, together with a systematic α to N by methyl groups, and assuming a CϪC bond length
sketch of the reaction coordinate, is presented in Figure 1. of 153 pm, it can be calculated that the two CH3 carbon
The distance dN1ϪW was allowed to vary from 225 pm to centres are separated by just 213 pm. This is within the
395 pm; it can be seen that the energy rises smoothly from range of the effective van der Waals radius of a methyl
0 kJ/mol (the reference value for the ground state) to 62 kJ/ group (200 pm). It seems likely that the transition-state geo-
mol (the transition state) and then decreases again (see Fig- metry of the intramolecular rearrangement of 11 does not
ure 1, solid line).
More interesting still are the changes in dN2ϪW as a func- exchange process is hindered for steric reasons.
tion of the value of dN1ϪW (Figure 1, dashed line). We ana- When a solution of 9a in chloroform was set aside for
allow the two pyridyl rings to pass each other. Thus, the
lysed this by following the actual linear transit mode, i.e. by several hours at room temperature, the formation of small
bringing the uncoordinated atom N1 in towards the dis- amounts of decarbonylated complex isomers with both
tance for binding to the metal centre. As the N1 atom ap- phosphane ligands coordinated in a bidentate fashion was
proaches (dN1ϪW in the range from 395 pm to 325 pm), the observed. On warming the solution to 70 °C, however, de-
four-membered metallacycle remains essentially intact and composition was observed by NMR spectroscopy. In order
dN2ϪW does not change significantly. At the transition state, to confirm the structures of the isomers, a specific synthesis
two equally long dNϪW distances are present. If N1 is now was developed [Equation (2)]. The monocarbonyl complex
brought closer to the metal centre, dN2ϪW immediately 20 with the phosphorus donors coordinated in a cis ar-
takes on values around 380 pm, the distance corresponding rangement was prepared by heating a suspension of 9b in
to the uncoordinated ring. From this, it might be concluded toluene to 100 °C with slow removal of the solvent under
that bond cleavage and bond formation do not occur in a slightly reduced pressure. A similar procedure was em-
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Eur. J. Inorg. Chem. 2000, 1411Ϫ1422

New Nitrosyltungsten Complexes
FULL PAPER
ployed to synthesize the trans isomer 21. In order to in- as well as uncoordinated phosphane (5%). The collected
crease the solubility of the cationic species, it was necessary solid was washed several times with diethyl ether and then
to replace the BF4 anion of 9a by BPh4, thereby affording taken up in a mixture of diethyl ether/dichloromethane.
the analogous complex 9b. Dissolution of 9b with a few Slow evaporation of the solvents afforded bright-yellow
drops of acetonitrile in toluene, heating to 95 °C, removal crystals of the desired product.
of the solvent under reduced pressure, and repeating of this
procedure afforded a red powder. Recrystallization from Me2Ppy
In contrast, the reaction of the more basic phosphanes
or Me2P-tert-Bupy with [W(CH3CN)3-
dichloromethane at Ϫ30 °C gave 21 as dark-red crystals. (CO)2(NO)][BF4] in dichloromethane resulted in the substi-
The 31P-NMR spectrum of the product featured an AB sys- tution of three acetonitrile ligands by P-coordinated phos-
tem (2JAB ϭ 121 Hz) along with the respective tungsten sat- phanes [Equation (4)]. The formation of the trisubstituted
ellites and characteristic JPW values of 277 Hz and 299 Hz complexes 16 and 18 could be observed by 31P-NMR spec-
for the two P atoms located in trans positions.
troscopy even after the addition of just one equivalent of
the phosphane ligand to the acetonitrile complex.
Complexes 16 and 18 were found to be very stable in
air in the solid state, and only slightly moisture-sensitive in
solution. When the former reaction was carried out in THF
using exactly two equivalents of the phosphane, the 31P-
NMR spectra of the reaction mixtures showed one singlet
with a JPW of 254 Hz for the Me2Ppy derivative and 257 Hz
for the Me2P-tert-Bupy derivative, indicating a cis arrange-
ment of the two phosphanes coordinated to the tungsten
centre. A further resonance of lower intensity was observed
in each case, which disappeared upon addition of acetonitr-
ile to the THF solution [Equation (5)]. Removal of the solv-
ents in vacuo (10Ϫ1 mbar) afforded complex 22 with one
Me2Ppy ligand coordinated to the metal centre in a monod-
entate fashion and the second coordinated in a bidentate
fashion, akin to the situation in complexes 9a and 11. With
Me2P-tert-Bupy ligands, however, the sterically demanding
tert-butyl substituent prevents coordination of the pyridine
ring and so complex 23a, with one acetonitrile ligand re-
maining coordinated to the metal centre, is formed. In con-
trast to the complexes bearing less bulky phosphanes, the
remaining acetonitrile ligand could not be removed from
the metal coordination sphere, even at elevated temper-
atures. Exchange of the BF4 anion by the more inert tetra-
A suitable reaction for preparing the cationic complex
14 bearing the bulky Ph2P-tert-Bupy ligands that avoided
coordination of the pyridine substituents, was found to be
nitrosylation of the neutral tetracarbonyl compound 12,
Equation (3).
A 20% excess of NOPF6 was found to be essential to kis[3,5-bis(trifluoromethyl)phenyl]borate (TFPB) 23b and
achieve complete transformation of 13. The crude product subsequent heating in vacuo (10Ϫ4 mbar) led only to slow
consisted of 14 (70%) and unidentified impurities (ca. 25%), decomposition of the complex.
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422
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H. Berke et al.
FULL PAPER
Preparation of the Tungsten Hydrides
Depending on the nature of the cationic nitrosyltungsten
complexes, three different hydride reagents were used to ob-
tain the corresponding tungsten hydride compounds. For
the cationic complexes 9a and 11, which have pyridine sub-
stituents coordinated at their metal centres, sodium bis(2-
methoxyethyloxy)aluminium hydride (RedAl) was found to
give the best yields, whereas for complex 14 sodium tetrahy-
droborate proved to be most efficient in displacing the car-
bonyl ligand. The resulting tungsten hydride complexes 10,
12, and 15 bearing diphenyl-substituted phosphanes were
readily precipitated by rapid addition of ethanol to the reac-
tion mixtures. The tert-butyl-substituted derivative 15 was
found to be slightly more soluble than 10 and 12 and there-
fore had to be precipitated at low temperature to prevent
further reaction of the hydride with the alcohol [Equa-
tion (6)].
Sodium hydrotrimethoxyborate was chosen for the reac-
tions with the trisubstituted phosphane cations 16 and 18,
which afforded the tungsten hydride complexes 17 and 19.
The phosphane ligands abstracted during these reactions
could not easily be removed from the products due to sim-
ilar solubility properties. However, in both cases
[W(CH3CN)3(CO)2(NO)][BF4] proved to be an efficient
phosphane scavanger affording the cationic starting com-
plex, from which the product could simply be separated by
extraction with pentane [Equation (7)].
Reactivity Studies
In order to assess the influence of the pyridyl substitu-
ents, complexes 10 and 12 were compared with the analog-
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Eur. J. Inorg. Chem. 2000, 1411Ϫ1422

New Nitrosyltungsten Complexes
FULL PAPER
ous compound trans-HW(CO)2(NO)(PPh3)2 prepared by logous P(OiPr)3 derivative.[24] The carbonyl intensity pat-
Hillhouse.[21] The NMR chemical shifts and coupling con- terns [2050 (w), 1962 (s) cmϪ1] in the infrared spectra are
stants of the carbonyl and hydride resonances, as well as characteristic of a trans-dicarbonyl geometry by analogy
the IR stretching vibrations for NO and CO, were found with the PPh3 derivative.
to be essentially identical for the three hydride complexes.
A further insertion experiment was performed by treating
Therefore, one can also expect a similar hydridic behaviour, 12 with dimethyl acetylenedicarboxylate in THF. The re-
as discussed previously by Berke et al.[22,23] for related com- sulting IR spectrum featured one carbonyl band at 1935
pounds.
cmϪ1 indicating the loss of a single carbonyl ligand. The
The reaction of 10 with HI (0.75  in CHCl3) led to the 1H- and 13C-NMR data of the resulting complex 27 were
immediate evolution of hydrogen affording trans- compared with those of the PMe3 derivative.[22] However, it
IW(CO)2(NO)(PPh2py)2 (25) [Equation (8)], as described could not be unambiguously established which of the two
for the PPh3 derivative.
isomers with regard to the positions of the NO and CO
ligands had been formed [Equation (11)].
Hydrogen was also evolved when 10 was treated with gla-
cial acetic acid in a mixture of dichloromethane and 2-pro-
panol. Subsequent loss of one carbonyl ligand resulted in
the formation of a four-membered metallacycle with the
formula trans-W(CO)(NO)(Ph2Ppy)2(η2-CH3CO2) (24)
[Equation (9)].
The above reactions displayed approximately the same
characteristics irrespective of whether a PPh2py or a PPh3
ligand was coordinated to the tungsten centre. According
to the spectroscopic data and the reactivities of the tungsten
hydride complexes, the pyridyl substituents seemingly have
no influence on the electronic character of the hydride li-
gand.
Nevertheless, an H/D exchange experiment was per-
formed in order to assess whether the basic pyridine N
atom had any effect on the reactivities of the hydride com-
plexes. The interaction of a protic alcohol function with the
pyridyl substituents located in the ligand sphere could facil-
itate proton transfer to the hydride. In order to compare
the H/D exchange rates of HW(CO)2(NO)(PPh3)2 and
HW(CO)2(NO)(PPh2py)2 (10) with [D4]methanol, a 1:1
mixture of the two complexes in CD2Cl2 was prepared and
then a 150-fold excess of [D4]methanol was added at 0 °C.
Higher temperatures (ϩ5 °C) led to rapid decomposition of
the complexes with evolution of HD. By monitoring the
The same decarbonylation reaction was also observed by
Hillhouse and afforded the analogous complex bearing
PPh3 ligands.
The insertion of carbon dioxide into the metal hydride
bond yielding the formato complex 26 was achieved by
slowly bubbling a stream of CO2 gas through a solution of
10 in THF [Equation (10)].
1
reaction by H-NMR spectroscopy for 25 min at 0 °C, it
was observed that the hydride resonance of 9 at δ ϭ Ϫ0.07
completely disappeared while in the 31P{1H}-NMR spectra
a triplet due to deuterated 9 with a PD coupling constant
of J ϭ 3 Hz appeared. In contrast, the analogous reson-
ances due to HW(CO)2(NO)(PPh3)2 did not change. After
22 hours, 10 had been completely consumed while only 30%
of the PPh3 complex had been transformed to the deuteride
with partial decomposition through ligand abstraction
[Equation (12)]. After a reaction time of one hour under
the same conditions and further addition of [D1]methanol
to the mixture, the deuteride complex 28 readily precipit-
The 1H-NMR resonance of the formate proton in 26 ap- ated and could be fully characterized.
pears at δ ϭ 7.06 (δ ϭ 7.08 for the PPh3 derivative). The
Although no spectroscopic evidence was found to sup-
oxo carbonyl resonance is seen at δ ϭ 166.4 in the 13C- port the concerted mechanism proposed in Equation (12),
NMR spectrum. Identical shifts have been observed for it could be concluded from these experiments that the inter-
other phosphane complexes incorporating monodentate action of the protic alcohol with the pyridyl substituent is
formate ligands prepared in our laboratory, such as the ana- responsible for the accelerated H/D exchange.
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422
1415

H. Berke et al.
FULL PAPER
We also carried out exploratory catalytic experiments
with the hydride complexes 10 and 19 in order to investigate
their activities in the ionic hydrogenation of imines. This
type of catalysis has been reported for a variety of Ru, Ir,
Rh, and Ti complexes. With compound 10, we obtained the
most promising results when a 5:1 mixture of isopropyliso-
propylideneamine and its corresponding BPh4 salt were dis-
solved in a 2:1 mixture of THF/CH2Cl2. The amount of
tungsten hydride catalyst used was 10 mol-% with respect
to the imine. Stirring the reaction mixture at 70 °C for 14
hours under 60 atm of hydrogen resulted in the conversion
of 35% of the imine and iminium salt to the corresponding
amine and ammonium salt, respectively. The 31P-NMR
spectra showed one resonance corresponding to the free
phosphane ligand. We conclude that about 3Ϫ4 turnovers
were reached before decomposition of the catalyst occurred.
Addition of the BPh4 salt was found to be essential to initi-
ate the reaction; no hydrogenation was observed if only the
pure imine was present in solution.
Figure 2. View of the structure of the cation of 9a; selected bond
˚
lengths (A) and angles (°): W(1)ϪN(1) 2.240, W(1)ϪP(1) 2.537,
W(1)ϪP(2) 2.536, W(1)ϪC(36) 2.046, W(1)ϪN(3) 1.809,
W(1)ϪC(35) 2.051; N(3)ϪW1ϪC(36) 95.11, N(3)ϪW1ϪC(35)
92.08,
N(3)ϪW1ϪN(1)
170.70,
N(3)ϪW1ϪP(2)
87.89,
N(3)ϪW1ϪP(1) 106.24, C(36)ϪW1ϪC(35) 89.41, C(36)Ϫ
W1ϪN(1) 94.12, C(36)ϪW1ϪP(2) 86.15, C(35)ϪW1ϪN(1) 86.95,
C(35)ϪW1ϪP(1) 86.70, N(1)ϪW1ϪP(2) 93.80, N(1)ϪW1ϪP(1)
64.48, P(2)ϪW1ϪP(1) 97.59
When the same experiment was performed using 19 as
the catalyst, an additional product could be observed in the
1H-NMR spectrum. Reference spectra and GC-MS analysis
confirmed the formation of both mono- and diisopropyl-
amine. Further investigations using hydrogen pressures up
to 100 atm and temperatures up to 90 °C led to changes in
the isopropylamine/diisopropylamine ratio from 1:2 (60 °C/
60 atm) up to 3:1 (90 °C/100 atm). The mechanisms of these
reactions have not yet been clarified and are currently under
investigation in our laboratory.
Figure 3. View of the structure of the cation of 11; selected bond
˚
lengths (A) and angles (°): W(1)ϪN(2) 2.259(5), W(1)ϪP(1)
2.539(2), W(1)ϪP(2) 2.564(1), W(1)ϪC(1) 2.046(7), W(1)ϪN(1)
1.810(5), W(1)ϪC(2) 2.047(6); P(1)ϪW(1)ϪP(2) 94.08(5),
P(1)ϪW(1)ϪN(1) 104.1(2), P(2)ϪW(1)ϪN(1) 91.5(2), P(1)Ϫ
W(1)ϪN(2) 64.5(1), P(2)ϪW(1)ϪN(2) 94.8(1), N(1)ϪW(1)ϪN(2)
167.3(2), P(2)ϪW(1)ϪC(1) 87.9(2), N(1)ϪW(1)ϪC(1) 89.8(2),
X-ray Crystal Structure Determinations
The following complexes were characterized by X-ray
analysis: cis,cis-[W(CO)2(NO)(Ph2Ppy)(η2-Ph2Ppy)][BF4]
(9a), cis,cis-[W(CO)2(NO)(Ph2Ppic)(η2-Ph2Ppic)][BF4] (11),
cis,mer-[W(CO)3(NO)(Ph2P-tert-Bupy)2][PF6] (14), and
cis,cis-[W(CO)(NO)(η2-Ph2Ppy)2][BF4] (20). In the Figures
the anions of all the structures have been omitted for the
sake of clarity.
N(2)ϪW(1)ϪC(1)
N(1)ϪW(1)ϪC(2)
101.4(2),
90.9(2),
P(1)ϪW(1)ϪC(2)
N(2)ϪW(1)ϪC(2)
88.2(2),
83.4(2),
C(1)ϪW(1)ϪC(2) 89.2(3), W(1)ϪP(1)ϪC(3) 83.6(2)
The WϪN(pyridyl) bond lengths in the monocarbonyl
˚
complex 20 (Figure 4) are 2.258(3) A for N(2) and 2.210(3)
˚
Compounds 9a (Figure 2) and 11 (Figure 3) show A for N(1). The longer WϪN(2) bond length can be attrib-
strongly distorted octahedra due to the formation of the uted to the strong trans influence of the nitrosyl ligand.
four-membered metallacycle with PϪWϪN bond angles of This effect is also manifested in the bond angles in the less
approximately 64.5° in each case. The WϪN(pyridyl) bond strained metallacycle, 65.50(9)° for N(2)ϪW(1)ϪC(2) [cf.
˚
length in 11 is only slightly lengthened to 2.259(5) A com- 64.12(9)° for N(1)ϪW(1)ϪC(1)].
˚
pared to 2.240 A in 9a. However, the steric influence of the
In compound 14 (Figure 5), the trans influence of the
methyl substituent in 11 is clearly apparent from the open- nitrosyl ligand is also reflected in the longer
˚
ing of the corresponding equatorial bond angles, phosphorusϪtungsten bond length, which is 2.640(2) A for
˚
N(1)ϪW(1)ϪC(36) in 9a and N(2)ϪW(1)ϪC(1) in 11, from W(1)ϪP(30), as compared to 2.591(2) A for W(1)ϪP(10)
94.12° to 101.4(2)°.
with a carbonyl ligand coordinated in a trans orientation.
1416
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422

New Nitrosyltungsten Complexes
FULL PAPER
automatic iteration mode. Sodium bis(2-methoxyethyloxy)alumin-
ium hydride (RedAl, 3.5  in toluene) was purchased from Aldrich
Chemical Co.
Sodium 3,3-Dimethyl-2-oxobutoxide (1): Sodium ribbon (15.2 g,
0.66 mol) was added to 350 mL of dry diethyl ether. A mixture of
ethyl formate (48.9 g, 0.66 mol) and pinacoline (66.1 g, 0.66 mol)
was then added dropwise to the reaction mixture over a period of
2 h at Ϫ30 °C. When the addition was complete, the solution was
allowed to warm to room temperature and stirring was continued
for a further 1 h. After evaporation of the solvent, the residual
brown slurry was washed with small amounts of diethyl ether and
hexane. The crude product was used in the next step without fur-
ther purification. Yield: 92.4 g (0.55 mol, 83%).
6-tert-Butyl-3-cyano-2-pyridone (2): Sodium salt 1 (92.4 g, 0.55 mol)
and cyanoacetamide (46.25 g, 0.55 mol) were dissolved in water
(200 mL). Meanwhile, a solution consisting of glacial acetic acid
(8 mL) and water (20 mL) was adjusted to pH ϭ 8 by the addition
Figure 4. View of the structure of the cation of 20; selected bond
˚
lengths (A) and angles (°): W(1)ϪP(10) 2.591(2), W(1)ϪP(30)
2.640(2), W(1)ϪN(4) 1.896(7), W(1)ϪC(1) 1.977(8), W(1)ϪC(2)
2.080(9), W(1)ϪC(3) 2.06(1); P(1)ϪW(1)ϪP(2) 98.41(3),
P(1)ϪW(1)ϪN(1) 64.12(9), P(2)ϪW(1)ϪN(1) 152.51(9), P(1)Ϫ of piperidine. The two solutions were then mixed and the mixture
W(1)ϪN(2) 84.40(8), P(2)ϪW(1)ϪN(2) 65.50(9), N(1)Ϫ
W(1)ϪN(2) 90.7(1), P(1)ϪW(1)ϪN(3) 96.7(1), P(2)ϪW(1)ϪN(3)
105.3(1), N(1)ϪW(1)ϪN(3) 98.0(1), P(2)ϪW(1)ϪC(1) 95.0(1),
N(1)ϪW(1)ϪC(1) 99.1(1), N(2)ϪW(1)ϪC(1) 90.9(1), N(3)Ϫ
was refluxed for 2 h, cooled, and acidified with glacial acetic acid.
After filtration, the brown residue was washed with water
(200 mL), taken up in ethanol (200 mL), and the resulting solution
W(1)ϪC(1) 90.7(2), W(1)ϪP(1)ϪC(2) 82.5(1), W(1)ϪP(2)ϪC(22) was treated with activated charcoal (5 g). Evaporation of the solv-
84.6(1), W(1)ϪN(1)ϪC(2) 108.9(3), W(1)ϪN(2)ϪC(22) 104.4(2)
ent in vacuo gave the product as a white powder. Yield: 22 g (0.125
mol, 23%); m.p. 194 °C. Ϫ 1H NMR (200 MHz, CDCl3): δ ϭ 12.59
3
3
(br., 1 H), 7.81 (d, JHH ϭ 7.7 Hz, 1 H), 6.26 (d, JHH ϭ 7.7 Hz, 1
H), 1.41 [s, 9 H, C(CH3)3]. Ϫ 13C NMR (200 MHz, CDCl3): δ ϭ
164.3 (s), 162.6 (s), 148.4 (s, CH), 115.6 (s), 102.2 (s, CH), 35.9 (s,
CMe3), 28.7 [s, C(CH3)3]. Ϫ MS (EI); m/z (%): 176 [Mϩ] (22), 161
[Mϩ Ϫ CH3] (100), 134 [Mϩ Ϫ CH3 Ϫ CN Ϫ H] (12). Ϫ
C10H12N2O (176.22): calcd. C 68.16, H 6.86, N 15.90; found C
67.89, H 6.47, N 15.82.
6-tert-Butyl-2-oxo-3-pyridinecarboxylic Acid (3): A solution of 2
(20.0 g, 0.11 mol) in concentrated hydrochloric acid (200 mL) was
refluxed for 5 h, poured onto 200 g of ice, and washed several times
with cold water. Evaporation of the water in vacuo gave the product
as a white solid. Yield: 18.76 g (96 mmol, 84%); m.p. 240 °C. Ϫ 1H
NMR (200 MHz, CDCl3): δ ϭ 13.80 (br., 1 H), 12.40 (br., 1 H),
3
3
8.54 (d, JHH ϭ 8 Hz, 1 H), 6.61 (d, JHH ϭ 8 Hz, 1 H), 1.46 [s, 9
H, C(CH3)3]. Ϫ 13C NMR (200 MHz, CDCl3): δ ϭ 166.1 (s), 165.4
(s), 164.0 (s), 148.1 (s, CH), 115.6 (s), 106.0 (s, CH), 36.4 (s, CMe3),
29.3 [s, C(CH3)3]. Ϫ MS (EI); m/z (%) ϭ 194 [Mϩ] (100), 179 [Mϩ
Ϫ CH3] (76), 177 [Mϩ Ϫ OH], 162 [Mϩ Ϫ CH3 Ϫ OH] (100). Ϫ
C10H13NO3: calcd. C 61.53, H 6.71, N 7.17; found C 61.96, H 6.30,
N 7.33.
Figure 5. View of the structure of the cation of 14; selected bond
˚
lengths (A) and angles (°): W(1)ϪP(10) 2.591(2), W(1)ϪP(30)
2.640(2), W(1)ϪN(4) 1.896(7), W(1)ϪC(1) 1.977(8), W(1)ϪC(2)
2.080(9), W(1)ϪC(3) 2.06(1); P(10)ϪW(1)ϪP(30) 104.39(6),
P(10)ϪW(1)ϪN(4) 82.0(2), P(30)ϪW(1)ϪC(1) 86.7(2), N(4)Ϫ
W(1)ϪC(1) 87.3(3), P(10)ϪW(1)ϪC(2) 91.2(2), P(30)ϪW(1)ϪC(2)
82.5(2), N(4)ϪW(1)ϪC(2) 91.7(3), C(1)ϪW(1)ϪC(2) 93.0(3),
P(10)ϪW(1)ϪC(3) 87.0(2), P(30)ϪW(1)ϪC(3) 91.5(2), N(4)Ϫ
W(1)ϪC(3) 94.7(3), C(1)ϪW(1)ϪC(3) 90.0(4), W(1)ϪP(10)ϪC(4)
113.3(3), W(1)ϪP(10)ϪC(13) 108.3(2), W(1)ϪP(10)ϪC(19)
121.5(3), W(1)ϪP(30)ϪC(34) 108.3(2), W(1)ϪP(30)ϪC(43)
114.7(3), W(1)ϪP(30)ϪC(49) 118.3(2)
6-tert-Butyl-2-pyridol (4): In a 500-mL flask fitted with a cold fin-
ger, 3 (18.0 g, 92.3 mol) was heated to 315 °C for 20 min by means
of a molten-metal bath. When the evolution of carbon dioxide had
ceased, the residual black material was sublimed at 150 °C and a
pressure of 0.1 mbar. The product was obtained in the form of
white crystals. Yield: 9.4 g (62 mmol, 67%); m.p. 141 °C. Ϫ 1H
NMR (300 MHz, CDCl3): δ ϭ 11.76 (br., 1 H), 7.34 (m, 1 H), 6.40
(m, 1 H), 6.09 (m, 1 H), 1.34 [s, 9 H, C(CH3)3]. Ϫ 13C NMR
(300 MHz, CDCl3): δ ϭ 165.0 (s), 157.1 (s), 141.7 (s, CH), 117.3
(s, CH), 101.9 (s, CH), 36.4 (s, CMe3), 29.3 [s, C(CH3)3]. Ϫ MS
(EI); m/z (%): 151 [Mϩ] (100), 136 [Mϩ Ϫ CH3] (100). Ϫ C9H13NO
(151.21): calcd. C 71.49, H 8.67, N 9.26; found C 71.26, H 8.48,
N 9.33.
Experimental Section
General Techniques: All preparations were carried out under dry
nitrogen using conventional Schlenk or glove-box techniques and
dry, air-free solvents. Ϫ IR spectra were recorded with a Bio-Rad
FTS-45 instrument. Ϫ 1H-, 13C-, and 31P-NMR spectra were re-
1
corded with a Varian Gemini 200 (200 MHz for H, 50.3 MHz for
13C), a Varian Gemini 300 (300 MHz for 1H, 121.5 MHz for 31P, 2-tert-Butyl-6-chloropyridine (5): To
a solution of 4 (9.0 g,
75.4 MHz for 13C), or a Bruker Avance 500 (125.8 MHz for 13C). 59.6 mmol) in refluxing phosphorus oxychloride (10 mL), phos-
All 31P-NMR spectra were proton-decoupled. The spectra were
simulated using the program gNMR 4.1 (Cherwell Scientific) in the
phorus pentachloride (13.8 g) was added in small portions over a
period of 30 min. The bath temperature was then increased to 160
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422
1417

H. Berke et al.
FULL PAPER
°C and maintained at this temperature for 1 h. After cooling the
mixture to room temperature and removing the solvent under re-
duced pressure, the residue was poured onto ice. The resulting
black mixture was made strongly basic with sodium hydroxide and
steam distilled to afford a pale oil. The crude product was taken
up in diethyl ether and dried with Na2SO4. Removal of the solvent
and distillation of the oil (b.p. 47 °C, 1 mbar) afforded a colourless
liquid. Yield: 5.4 g (32.3 mmol, 48%), Ϫ 1H NMR (300 MHz,
tained as large white needles. Yield: 460 mg (0.294 mmol, 77%). Ϫ
1H NMR (300 MHz, CDCl3): δ ϭ 7.44 (m, 1 H, py), 7.37 (m, 10
H, Ph), 7.05 (m, 1 H, py), 6.83 (m, 1 H, py), 2.58 (s, 3 H, CH3). Ϫ
31P NMR (300 MHz, CDCl3): δ ϭ Ϫ4.4 (s). Ϫ 13C NMR
3
(300 MHz, CDCl3): δ ϭ 162.9 (d, JCP ϭ 7 Hz, ipso-py), 158.9 (d,
1
1JCP ϭ 15 Hz, ipso-py), 136.5 (d, JCP ϭ 15 Hz, ipso-Ph), 135.8 (d,
JCP ϭ 2 Hz, py), 134.0 (d, JCP ϭ 20 Hz, Ph), 128.8 (s, Ph), 128.4
(d, JCP ϭ 7 Hz, Ph), 124.8 (d, J ϭ 11 Hz, py), 121.9 (s, py), 24.6
CDCl3): δ ϭ 7.55 (m, 1 H, py), 7.22 (m, 1 H, py), 7.10 (m, 1 H, (s, CH3). Ϫ MS (EI); m/z (%): 277 [Mϩ] (100), 200 [Mϩ Ϫ Ph] (30),
py), 1.35 [s, 9 H, C(CH3)3]. Ϫ 13C NMR (300 MHz, CDCl3): δ ϭ 185 [Mϩ Ϫ Ph Ϫ CH3] (12). Ϫ C18H16NP (277.31): calcd. C 77.96,
170.6 (s, α-C, py), 150.2 (s, α-C, py), 138.7 (s, py), 121.1 (s, py),
117.4 (s, py), 37.5 (s, CMe3), 29.9 [s, C(CH3)3]. Ϫ MS (EI); m/z
(%): 169 [Mϩ] (88), 154 [Mϩ Ϫ CH3] (100). Ϫ C9H12NCl (169.66):
calcd. C 63.72, H 7.13, N 8.26; found C 63.94, H 7.08, N 8.18.
H 5.82, N 5.05; found C 78.31, H 5.56, N 4.97.
cis,cis-[W(CO)2(NO)(Ph2Ppy)(η2-Ph2Ppy)][BF4] (9a): To a solution
of [W(CH3CN)3(CO)2(NO)][BF4] (1.5 g, 3.13 mmol) in dichloro-
methane was added tris(2-pyridyl)phosphane (1.65 g, 6.27 mmol).
After stirring the reaction mixture for 1 h at room temperature, it
was concentrated to a volume of 7 mL in vacuo and diethyl ether
2-(6-tert-Butylpyridyl)diphenylphosphane (6): To a solution of di-
phenylphosphane (2.75 g, 14.8 mmol) in THF (50 mL) at room
temperature, 1.6  nBuLi in THF (9.25 mL, 14.8 mmol) was added (5 mL) was slowly added, which induced the formation of a dark-
dropwise over a period of 30 min. The resulting red solution was
stirred for a further 30 min and then a solution of 5 (2.5 g,
14.7 mmol) in THF (10 mL) was slowly added. The reaction mix-
ture was stirred for a further 14 h, then quenched with ethanol
(15 mL), and the solvents were evaporated under reduced pressure.
The resulting pale-yellow solid was redissolved in hexane (200 mL)
yellow oil. The residue was dissolved in dichloromethane and di-
ethyl ether (10 mL) was again slowly added, which led to the depos-
ition of a yellow solid. The precipitate was filtered off and washed
with diethyl ether (2 ϫ 10 mL) to give 9a as a yellow powder. Yield:
2.2 g (2.49 mmol, 80%). Ϫ 1H NMR (200 MHz, Ϫ30 °C, CD2Cl2):
δ ϭ 8.51Ϫ7.55 (m, Ph ϩ py). Ϫ 31P NMR (300 MHz, Ϫ30 °C,
2
and this solution was treated with activated charcoal (5 g). After CD2Cl2): δ ϭ Ϫ25.1 (d, JPP ϭ 22 Hz, JPW ϭ 267 Hz), Ϫ18.6 (d,
filtration and evaporation of the solvent, white crystals were ob-
2JPP ϭ 22 Hz, JPW ϭ 220 Hz). Ϫ 13C NMR (300 MHz, Ϫ30 °C,
tained. Yield: 3.0 g (9.46 mmol, 64%). Ϫ 1H NMR (300 MHz, CD2Cl2): δ ϭ 213.0 (dd, 2JCP ϭ 5 ϫ 36 Hz, CO), 207.9 (dd, 2JCP ϭ
CDCl3): δ ϭ 7.51Ϫ7.35 (m, 10 H, Ph; 1 H, py), 7.21 (m, 1 H, py),
6 ϫ 42 Hz, CO). Ϫ IR (CH2Cl2): ν˜ ϭ 2037 cmϪ1 (s), 1966 (s), 1676
6.97 (m, 1 H, py), 1.34 (s, 9 H, tBu). Ϫ 31P NMR (300 MHz, (m). Ϫ MS (FAB); m/z (%): 796 [Mϩ] (80), 768 [Mϩ Ϫ CO] (75).
CDCl3): δ ϭ Ϫ3.4 (s). Ϫ 13C NMR (200 MHz, CDCl3): δ ϭ 169.3 Ϫ C36H28BF4N3O3P2W (883.24): calcd. C 48.96, H 3.20, N 4.76;
1
3
(d, JCP ϭ 10 Hz, ipso-py), 161.6 (d, JCP ϭ 5 Hz, ipso-py), 137.1
found C 48.78, H 3.02, N 4.51.
1
(d, JCP ϭ 9 Hz, ipso-Ph), 135.6 (d, JCP ϭ 4 Hz, py), 134.2 (d,
cis,cis-[W(CO)2(NO)(Ph2Ppy)(η2-Ph2Ppy)][BPh4] (9b): A mixture
of 9a (300 mg, 0.34 mmol) and sodium tetraphenylborate (116 mg,
0.34 mmol) was stirred in THF (8 mL) for 30 min and then filtered
through Celite. After removing the solvent in vacuo, the yellow oil
was taken up in dichloromethane and filtered through a small pad
of silica gel. The filtrate was then concentrated to a volume of 1 mL
JCP ϭ 20 Hz, Ph), 128.6 (s, Ph), 128.2 (d, JCP ϭ 7 Hz, Ph), 125.0
(d, J ϭ 20 Hz, py), 117.3 (s, py). Ϫ MS (FAB); m/z (%): 319 [Mϩ]
(95), 185 [Mϩ Ϫ tert-Bupy] (10). ؊ C21H22NP (319.39): calcd. C
78.97, H 6.94, N 4.39; found C 78.74, H 6.73, N 4.21.
2-(6-tert-Butylpyridyl)dimethylphosphane (7): To a solution of tetra-
methyldiphosphane (4.4 g, 36 mmol) in THF (300 mL) was added in vacuo and diethyl ether (4 mL) was added to precipitate the
potassium metal (2.82 g, 72.1 mmol). The mixture was stirred for
1 day at 35 °C and then the unchanged potassium metal was re-
moved. To the yellow solution of potassium dimethylphosphide
was added 5 (12.1 g, 71.3 mmol). The resulting dark-red solution
was stirred for 2 h, the solvent was evaporated in vacuo, and the
residue was extracted with diethyl ether (3 ϫ 50 mL). The com-
bined dark-red extracts were distilled under reduced pressure (b.p.
62Ϫ72 °C, 0.1 mbar) to give a colourless oil (9.4 g), which proved
to be an azeotropic mixture of 7 and unchanged 2-tert-butyl-6-
chloropyridine. The ratio of the mixture was estimated from the
product as a yellow solid. The collected product was washed with
pentane (3 ϫ 5 mL) and recrystallized from CH2Cl2/Et2O to give
yellow crystals. Yield: 300 mg (0.25 mmol, 73%). Ϫ 1H NMR
(300 MHz, Ϫ30 °C, CD2Cl2): δ ϭ 8.25Ϫ6.75 (m). Ϫ 31P NMR
(300 MHz, Ϫ30 °C, CD2Cl2): δ ϭ 24.8 (d, JPP ϭ 21 Hz, JPW
ϭ
267 Hz), Ϫ18.3 (d, JPP ϭ 21 Hz, JPW ϭ 219 Hz). Ϫ 13C NMR
2
(300 MHz, Ϫ30 °C, CD2Cl2): δ ϭ 212.9 (dd, JCP ϭ 5 ϫ 36 Hz,
CO), 207.5 (dd, 2JCP ϭ 6 ϫ 43 Hz, CO). Ϫ IR (CH2Cl2): ν˜ ϭ 2037
cmϪ1 (s), 1966 (s), 1677 (m). Ϫ MS (FAB-POS): m/z (%) ϭ 796
[Mϩ] (4), 768 [Mϩ Ϫ CO] (4). Ϫ C60H48BN3O3P2WCH2Cl2
1H-NMR spectrum to be 3:2. Ϫ 1H NMR (300 MHz, CDCl3): δ ϭ (1200.6): calcd. C 61.04, H 4.20, N 3.50; found C 60.97, H 4.17,
2
7.45 (m, py, 2 H), 7.15 (m, py, 1 H), 1.36 [d, 6 H, JPH ϭ 2.2 Hz,
(CH3)2P], 1.35 (s, 9 H, tBu). Ϫ 31P NMR (300 MHz, CDCl3): δ ϭ
Ϫ40.6 (s).
N 3.54.
trans,trans-HW(CO)2(NO)(Ph2Ppy)2 (10): To a solution of 9a
(340 mg, 0.374 mmol) in THF (25 mL), sodium dihydrobis(2-me-
thoxyethyloxy)aluminate (10.8 mL, 0.035  in THF) was slowly ad-
ded at 0 °C. After stirring for 10 min at room temperature, the
2-(6-Methylpyridyl)diphenylphosphane (8): To a solution of di-
phenylphosphane (3.68 g, 19.8 mmol) in THF (70 mL) at room
temperature, 1.6  n-butyllithium (12.4 mL, 20.2 mmol) was added reaction mixture was concentrated to a volume of 3 mL in vacuo
over a period of 30 min. After stirring for a further 30 min at room
temperature, the red reaction mixture was cooled to 0 °C and a
solution of 6-chloro-2-picoline (2.53 g, 19.8 mmol) in THF (20 mL)
was added dropwise. Further stirring for 3 h at room temperature
and subsequent addition of ethanol (20 mL) gave a pale-yellow so-
lution. The solvent was evaporated under reduced pressure and the
residue was extracted with hexane (400 mL). After filtration
through Celite and crystallization at Ϫ30 °C, the product was ob-
and ethanol (8 mL) was added dropwise to precipitate the product.
The mixture was filtered, and the collected yellow solid was sequen-
tially washed with ethanol (2 ϫ 5 mL) and diethyl ether (2 ϫ 3 mL)
to give a bright-yellow powder. Yield: 220 mg (0.276 mmol, 74%).
1
Ϫ H NMR (300 MHz, C6D6): δ ϭ 8.44 (m, 2 H, py), 7.92 (m, 8
H, Ph), 7.64 (m, 2 H, py), 7.08Ϫ6.94 (m, 12 H, Ph), 6.84 (m, 2 H,
py), 6.39 (m, 2 H, py), 0.62 (t, 1 H, JPH ϭ 22.4 Hz, JWH ϭ 31.1 Hz).
؊
31P NMR (300 MHz, C6D6): δ ϭ 30.3 (s, JPW ϭ 289 Hz). Ϫ 13C
1418
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422

New Nitrosyltungsten Complexes
FULL PAPER
2
NMR (300 MHz, C6D6): δ ϭ 217.2 (t, JCP ϭ 7 Hz, CO). Ϫ IR NOPF6 (42 mg, 0.24 mmol). The resulting mixture was vigorously
(CH2Cl2): ν˜ ϭ 1935 cmϪ1 (s), 1689 (m), 1595 (m). Ϫ MS (FAB); stirred, in the course of which it darkened in colour from yellow to
m/z (%): 797 [Mϩ] (4), 769 [Mϩ Ϫ CO] (20), 740 [Mϩ Ϫ 2 CO]
green-orange. When the evolution of CO had ceased, a further por-
(25). Ϫ C36H29N3O3P2W (797.45): calcd. C 54.22, H 3.67, N 5.27; tion of NOPF6 (8.4 mg) was added and stirring was continued for
found C 53.96, H 3.92, N 5.04.
15 h. The reaction mixture was then concentrated to a volume of
ca. 0.5 mL in vacuo and benzene (6 mL) was added. Concentration
of this solution to a volume of 3 mL led to the separation of a
green oil. The pale-yellow solution was decanted and the residue
was washed with diethyl ether (2 ϫ 4 mL). The crude product was
recrystallized from CH2Cl2/Et2O by slow evaporation of the solvent
mixture at atmospheric pressure to give bright-yellow crystals.
Yield: 109 mg (1.01 mmol, 50%). Ϫ 1H NMR (300 MHz, CD2Cl2):
cis,cis-[W(CO)2(NO)(Ph2Ppic)(η2-Ph2Ppic)][BF4] (11): To a solu-
tion of [W(CH3CN)3(CO)2(NO)][BF4] (170 mg, 0.354 mmol) in
dichloromethane (5 mL) was added 2-(6-methylpyridyl)diphenyl-
phosphane (196 mg, 0.71 mmol). After stirring for 90 min at room
temperature, the reaction mixture was concentrated to a volume of
approximately 2.5 mL, whereupon diethyl ether was slowly added.
The resulting yellow precipitate was collected by filtration and
washed with pentane. The product could be conveniently recrystal-
lized from CH2Cl2/Et2O to give yellow crystals. Yield: 320 mg
(249 mmol, 91%). Ϫ 1H NMR (300 MHz, CD2Cl2): δ ϭ 8.20Ϫ6.70
δ ϭ 7.75Ϫ6.80 (m, 26 H, Ph ϩ py), 1.42 (s, 9 H, CH3), 1.32 (s, 9
2
H, CH3). Ϫ 31P NMR (300 MHz, CD2Cl2): δ ϭ 18.7 (d, JPP
ϭ
2
22 Hz, JPW ϭ 263 Hz), 12.5 (d, JPP ϭ 22 Hz, JPW ϭ 178 Hz). Ϫ
13C NMR (300 MHz, CD2Cl2): δ ϭ 200.6 (t, JCP ϭ 8 Hz, CO),
2
(m, 26 H, Ph ϩ py), 2.40 (s, 3 H, CH3), 2.28 (s, 3 H, CH3). Ϫ 31P
2
198.1 (dd, JCP ϭ 8 ϫ 34 Hz, CO), 38.5 (s, 1CMe3), 38.6 (s,
2
NMR (300 MHz, CD2Cl2): δ ϭ 23.6 (d, JPP ϭ 21 Hz, JPW
ϭ
1CMe3), 30.1 [s, 2C(CH3)3]. Ϫ IR (CH2Cl2): ν˜ ϭ 2099 cmϪ1 (w),
2025 (s, sh), 1730 (m). Ϫ MS (FAB); m/z (%): 921 [Mϩ Ϫ CH3]
(27), 852 [Mϩ Ϫ 3 CO] (100), 561 [Mϩ Ϫ 2 CO Ϫ L] (51), 533 [Mϩ
Ϫ 3 CO Ϫ L] (76). Ϫ C45H44F6N3O4P3F6W (1081.63): calcd. C
49.97, H 4.10, N 3.88; found C 49.89, H 3.99, N 3.91.
2
269 Hz), Ϫ22.8 (d, JPP ϭ 21 Hz, JPW ϭ 215 Hz). Ϫ 13C NMR
2
(300 MHz, CD2Cl2): δ ϭ 211.2 (dd, JCP ϭ 7 ϫ 39 Hz, CO), 207.8
2
(dd, JCP ϭ 6 ϫ 42 Hz, CO), 25.4 (s, CH3), 24.2 (s, CH3). Ϫ IR
(CH2Cl2): ν˜ ϭ 2036 cmϪ1 (s), 1967 (s), 1675 (m). Ϫ MS (FAB); m/z
(%): 824 [Mϩ] (38), 796 [Mϩ Ϫ CO] (30), 768 [Mϩ Ϫ 2 CO] (10).
Ϫ C38H32BF4N3O3P2WCH2Cl2 (996.23): calcd. C 47.02, H 3.44, N
4.22; found C 46.83, H 3.15, N 4.42.
trans,trans-HW(CO)2(NO)(Ph2-tert-Bupy)2 (15): To a solution of
14 (109 mg, 0.101 mmol) and 6 (120 mg, 0.379 mmol) in THF
(3 mL) was added sodium tetrahydroborate (15 mg, 0.397 mmol).
Upon addition of the tetrahydroborate, the reaction mixture slowly
evolved carbon monoxide and darkened in colour from yellow to
dark-orange. After stirring for 30 min at 40 °C, the mixture was
concentrated to a volume of 0.5 mL in vacuo and ethanol (4 mL)
was added to induce precipitation of the yellow product. After fil-
tration and washing of the collected solid with ethanol (2 ϫ 2 mL)
and pentane (2 ϫ 2 mL), a yellow powder was obtained. Yield:
25 mg (0.038 mmol, 38%). Ϫ 1H NMR (300 MHz, CD2Cl2): δ ϭ
7.70Ϫ7.25 (m, 26 H, Ph ϩ py), 1.27 (s, 18 H, CH3), Ϫ0.18 (t, 1 H,
trans,trans-HW(CO)2(NO)(Ph2Ppic)2 (12): To a solution of 9
(700 mg, 0.770 mmol) in THF (25 mL), sodium bis(2-methoxy-
ethyloxy)dihydroaluminate (2.2 mL, 0.35  in THF) was slowly ad-
ded at 0 °C. After stirring for 1 h at room temperature, the reaction
mixture was concentrated to a volume of 2 mL in vacuo, where-
upon ethanol (50 mL) was added dropwise to precipitate the prod-
uct. The mixture was filtered, and the collected yellow solid was
sequentially washed with ethanol (2 ϫ 10 mL) and diethyl ether (2
ϫ 10 mL) to give a yellow powder. Yield: 355 mg (0.43 mmol,
1
J
PH ϭ 22.5 Hz, JWH ϭ 31.0 Hz). Ϫ 31P NMR (300 MHz, CD2Cl2):
56%). Ϫ H NMR (300 MHz, CD2Cl2): δ ϭ 7.70Ϫ7.05 (m, 26 H,
δ ϭ 29.4 (s, JPW ϭ 287 Hz). Ϫ 13C NMR (300 MHz, CD2Cl2): δ ϭ
Ph ϩ py), 2.55 (s, 6 H, CH3), Ϫ0.06 (t, 1 H, JPH ϭ 24.2 Hz, JWH ϭ
31.6 Hz). Ϫ 31P NMR (300 MHz, CD2Cl2): δ ϭ 31.1 (s, JPW
ϭ
2
217.0 (t, JCP ϭ 7 Hz, CO), 38.2 (s, CMe3), 30.1 [s, C(CH3)3]. Ϫ
292 Hz). Ϫ 13C NMR (300 MHz, CD2Cl2): δ ϭ 215.6 (t, JCP
ϭ
2
IR (CH2Cl2): ν˜ ϭ 1931 cmϪ1 (s), 1685 (m), 1594 (m). Ϫ MS (FAB);
m/z (%): 797 [Mϩ] (4), 769 [Mϩ Ϫ CO] (20), 740 [Mϩ Ϫ 2CO] (25).
Ϫ C44H45N3O3P2W (909.66): calcd. C 58.10, H 4.99, N 4.62; found
C 58.27, H 5.13, N 4.39.
6 Hz, CO), 24.5 (s, CH3). Ϫ IR (CH2Cl2): ν˜ ϭ 1937 cmϪ1 (s), 1680
(m), 1592 (m). Ϫ MS (FAB); m/z (%): 826 [Mϩ] (12), 797 [Mϩ
Ϫ
CO Ϫ H] (40), 769 [Mϩ Ϫ 2 CO Ϫ H] (25). Ϫ C38H33N3O3P2W
(825.5): calcd. C 55.29, H 4.03, N 5.09; found C 55.49, H 3.98,
N 5.03.
[W(CO)2(NO)(Me2Ppy)3][BF4]
(16):
To
a
solution
of
[W(CH3CN)3(CO)2(NO)][BF4] (960 mg, 1.88 mmol) in dichlorome-
thane (15 mL) was added Me2Ppy (790 mg, 5.68 mmol) and the
reaction mixture was stirred for 1 h at room temperature. It was
then concentrated to a volume of 5 mL in vacuo and carefully
layered with diethyl ether. After 3 d at Ϫ30 °C, orange crystals had
separated. Yield: 1.26 g (1.34 mmol, 90%). Ϫ 1H NMR (300 MHz,
CD2Cl2): δ ϭ 8.73 (m, 3 H, py), 7.83 (m, 3 H, py), 7.51 (m, 3 H,
cis/trans-W(CO)4(Ph2P-tert-Bupy)2 (13): To a solution of Ph2P-tert-
Bupy (390 mg, 1.23 mmol) in toluene (12 mL) was added tetracar-
bonyldi(piperidine)tungsten (280 mg, 0.60 mmol). The resulting
yellow suspension was refluxed and stirred for 90 min, in the course
of which homogeneity was attained. After filtration through a short
pad of silica gel, the solvent was evaporated from the filtrate to
afford the product as a mixture of isomers. Yield: 480 mg
(0.51 mmol, 86%). The pure trans isomer could be isolated by col-
umn chromatography. Ϫ 1H NMR (300 MHz, CDCl3): δ ϭ
7.75Ϫ7.15 (m, 26 H, Ph ϩ py), 1.35 [s, 18 H, C(CH3)3]. Ϫ 31P
NMR (300 MHz, CDCl3): δ ϭ 29.8 (s, JPW ϭ 284 Hz). Ϫ 13C
NMR (300 MHz, CDCl3): δ ϭ 203.3 (t, J ϭ 6 Hz, CO), 38.0 (s,
CMe3), 30.0 (s, CH3). Ϫ IR (CH2Cl2): ν˜ ϭ 1890 cmϪ1 (s). Ϫ MS
(FAB); m/z (%): 920 [Mϩ Ϫ CH3] (18), 850 [Mϩ Ϫ 3 CO] (4), 821
[Mϩ Ϫ 4 CO] (6), 503 [Mϩ Ϫ 4 CO Ϫ L] (25). Ϫ C46H44N2O4P2W
(934.67): calcd. C 59.11, H 4.75, N 3.00; found C 59.09, H 5.05,
N 2.93.
py), 7.40 (m, 3 H, py), 1.89 (m, 12 H, CH3), 1.79 (m, 6 H, CH3).
2
Ϫ
31P NMR (300 MHz, CD2Cl2): δ ϭ Ϫ16.6 (d, JPP ϭ 25 Hz,
JPW ϭ 251 Hz), Ϫ21.9 (t, JPP ϭ 25 Hz, JPW ϭ 165 Hz). Ϫ 13C
NMR (300 MHz, CD2Cl2): δ ϭ 208.2 (m, CO), 15.7 [m, P(CH3)2].
Ϫ IR (CH2Cl2): ν˜ ϭ 2029 cmϪ1 (s), 1955 (s), 1683 (m). Ϫ MS
2
(FAB): m/z (%) ϭ 687 [Mϩ] (82), 548 [Mϩ Ϫ L] (70), 520 [Mϩ
Ϫ
CO
Ϫ
L] (79), 492 [Mϩ
Ϫ
2
CO
Ϫ
L] (22).
Ϫ
C23H30BF4N4O3P3WCH2Cl2 (942.41): calcd. C 33.56, H 3.75, N
6.52; found C 33.78, H 3.57, N 6.92.
cis/trans-HW(CO)2(NO)(Me2Ppy)2 (17): To THF (6 mL) was ad-
ded 16 (225 mg, 0.29 mmol) and sodium hydrotrimethoxyborate.
The resulting mixture was stirred for 30 min at room temperature
[W(CO)3(NO)(Ph2P-tert-Bupy)2][PF6] (14): To a solution of 13
(190 mg, 0.203 mmol) in dichloromethane (5 mL) was added and then the solvent was removed in vacuo. The dark-red residue
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422 1419

H. Berke et al.
was extracted with pentane (3 ϫ 5 mL) and the combined extracts the solvent was pumped off in a vacuum line to about half of the
FULL PAPER
were filtered through Celite. Evaporation of the solvent from the
filtrate afforded an orange oil, which was taken up in dichlorome-
thane (5 mL). To this solution, [W(CH3CN)3(CO)2(NO)][BF4]
(72 mg, 0.15 mmol) was added to trap uncoordinated Me2Ppy. The
reaction mixture was stirred for 30 min and then the solvent was
evaporated in vacuo. The brown residue was extracted with pentane
(3 ϫ 5 mL) and the combined extracts were filtered through Celite
and concentrated to dryness. The product was obtained as a mix-
ture of isomers in the form of a yellow oil (cis/trans ratio, 20:80).
original volume over a period of 20 min. A further 5 mL of toluene
was then added and the procedure was repeated. After cooling to
room temperature, the solvent was decanted from the dark-orange
residue and the latter was washed with THF (3 ϫ 5 mL) and pent-
ane (5 mL). The product could be recrystallized from CH2Cl2/Et2O
to give orange crystals. Yield: 68 mg (0.079 mmol, 71%). Ϫ 1H
NMR (300 MHz, CD3NO2): δ ϭ 9.30 (m, 1 H), 8.36 (m, 1 H), 7.95
(m, 6 H), 7.74 (m, 4 H), 7.56 (m, 9 H), 7.30 (m, 3 H), 7.05 (m, 2
H), 6.48 (m, 2 H). Ϫ 31P NMR (300 MHz, CD3NO2): δ ϭ 2.3 (d,
Yield: 64 mg (0.117 mmol, 40%). Ϫ MS (FAB); m/z (%): 548 [Mϩ] JPP ϭ 16 Hz, JPW ϭ 328 Hz), Ϫ12.8 (d, JPP ϭ 16 Hz, JPW
ϭ
2
(66), 520 [Mϩ Ϫ CO] (100), 505 [Mϩ Ϫ 2 CO Ϫ CH3] (22), 492 180 Hz). Ϫ 13C NMR (300 MHz, CD2Cl2): δ ϭ 232.5 (d, JCP
ϭ
[Mϩ
Ϫ
2CO] (32), 477 [Mϩ
Ϫ
2
CO
Ϫ
CH3] (16).
Ϫ
47 Hz, CO). Ϫ IR (CH2Cl2): ν˜ ϭ 1920 cmϪ1 (s), 1611 (s). Ϫ MS
C16H21N3O3P2W (549.16): calcd. C 34.99, H 3.85, N 7.65; found
(FAB); m/z (%): 768 [Mϩ] (34), 740 [Mϩ
C35H28BF4N3O2P2W (855.23): calcd. C 49.15, H 3.30, N 4.91;
Ϫ CO] (5). Ϫ
C 35.03, H 3.96, N 7.58. Ϫ NMR data (cis isomer): 1H NMR
(300 MHz, C6D6): δ ϭ 8.22 (m, 2 H, py), 7.60 (m, 2 H, py), 6.88 found C 49.32, H 3.20, N 4.83.
(m, 2 H, py), 6.42 (m, 2 H, py), 1.62 (m, 12 H, PCH3), 0.22 (t, 1
trans,trans-[W(CO)(NO)(η2-Ph2Ppy)2][BPh4] (21): To a solution of
H, JPH ϭ 27.2 Hz, JWH ϭ 33.3 Hz). Ϫ 31P NMR (300 MHz, C6D6):
δ ϭ Ϫ15.1 (s, JPW ϭ 251 Hz). Ϫ 13C NMR (500 MHz, C6D6): δ ϭ
217.1 (m, CO), 19.0 [m, P(CH3)2]. Ϫ NMR data (trans isomer): 1H
NMR (300 MHz, C6D6): δ ϭ 8.42 (m, 2 H, py), 7.85 (m, 2 H, py),
7.05 (m, 2 H, py), 6.49 (m, 2 H, py), 1.89 (m, 12 H, PCH3), Ϫ0.81
(t, 1 H, JPH ϭ 25.6 Hz, JWH ϭ 30.2 Hz). Ϫ 31P NMR (300 MHz,
C6D6): δ ϭ Ϫ11.1 (s, JPW ϭ 280 Hz). Ϫ 13C NMR (500 MHz,
9b (60 mg, 0.05 mmol) in acetonitrile (1 mL) was added toluene
(8 mL) and the mixture was slowly concentrated to a volume of
6 mL in vacuo at a bath temperature of 80 °C. The concentrated
solution was then stirred for 2 h at 95 °C under slightly reduced
pressure. After pumping off the solvent, the red residue was redis-
solved in acetonitrile (1 mL) and toluene (8 mL). After stirring for
a further 3 h at 95 °C, the volume was reduced to 2 mL in vacuo.
The mixture was filtered and a red solid was crystallized at Ϫ30
2
C6D6): δ ϭ 216.9 (t, JCP ϭ 7 Hz, CO), 20.1 [m, P(CH3)2].
[W(CO)2(NO)(Me2P-tert-Bupy)3][BF4] (18): To
a
solution of °C by layering a cold dichloromethane solution with diethyl ether
and leaving the system to stand overnight. Yield: 35 mg
[W(CH3CN)3(CO)2(NO)][BF4] (715 mg, 1.49 mmol) in dichlorome-
thane (15 mL) was added an azeotropic mixture of Me2P-tert-Bupy (0.029 mmol, 59%). Ϫ 1H NMR (300 MHz, CD2Cl2): δ ϭ 8.2Ϫ6.7
(1.31 g, ca. 4.5 mmol) and the reaction mixture was stirred for 18 h
at room temperature. The resulting dark-orange solution was then
concentrated to a volume of 2 mL, whereupon diethyl ether was
added dropwise to induce precipitation of the orange product.
After washing with diethyl ether (3 ϫ 5 mL) and pentane (3 ϫ
5 mL), the pure product was obtained as an orange solid. Yield:
1.26 g (1.34 mmol, 90%). Ϫ 1H NMR (300 MHz, CD2Cl2): δ ϭ
7.74 (m, 3 H, py), 7.43 (m, 3 H, py), 7.25 (m, 1 H, py), 7.07 (m, 2
H, py), 1.90 (m, 12 H, CH3), 1.72 (m, 6 H, CH3), 1.37 (s, 18 H,
tBu), 1.36 (s, 9 H, tBu). Ϫ 31P NMR (300 MHz, CD2Cl2): δ ϭ
Ϫ20.8 (d, 2JPP ϭ 22.9 Hz, JPW ϭ 243 Hz), Ϫ21.9 (t, 2JPP ϭ 23 Hz,
JPW ϭ 158 Hz). Ϫ 13C NMR (300 MHz, CD2Cl2): δ ϭ 208.3 (m,
CO), 38.4 [s, C, C(CH3)3], 30.2 [s, C, C(CH3)3], 16.0 [m, P(CH3)2].
Ϫ IR (CH2Cl2): ν˜ ϭ 2026 cmϪ1 (s), 1957 (s), 1687 (m). Ϫ MS
(FAB); m/z (%): 856 [Mϩ] (80), 633 [Mϩ Ϫ CO Ϫ L] (12), 605 [Mϩ
Ϫ 2 CO Ϫ L] (60). Ϫ C35H54BF4N4O3P3W (942.41): calcd. C 44.61,
H 5.78, N 5.94; found C 44.33, H 5.55, N 5.72.
(m, Ph ϩ py). Ϫ 31P NMR (300 MHz, CD2Cl2): δ ϭ Ϫ0.5 (m, 2
P, AB system, JPaPb ϭ 121 Hz, JPaW ϭ 277 Hz, JPbW ϭ 299 Hz).
Ϫ
13C NMR (300 MHz, CD2Cl2): δ ϭ 237.1 (m, CO). Ϫ IR
(CH2Cl2): ν˜ ϭ 1920 cmϪ1 (s), 1625 (s). Ϫ MS (FAB); m/z (%): 768
[Mϩ] (18). Ϫ C59H48BN3O2P2W CH2Cl2 (1172.6): calcd. C 61.46,
H 4.30, N 3.58; found C 61.86, H 4.44, N 3.88.
cis,cis-[W(CO)2(NO)(Me2Ppy)(η2-Me2Ppy)][BF4] (22): To a solu-
tion of [W(CH3CN)3(CO)2(NO)][BF4] (214 mg, 0.447 mmol) in
THF (12 mL) was added Me2Ppy (125 mg, 0.9 mmol). The transi-
ent formation of a yellow suspension could be observed before the
reaction mixture became homogeneous again. After stirring over-
night at room temperature, half of the solvent was evaporated in
vacuo. Toluene (6 mL) was then added, stirring was continued for
a further 5 min, and then the solvent was removed in vacuo. The
resulting dark-yellow oil was taken up in dichloromethane (5 mL)
and the product was precipitated by the slow addition of pentane.
The supernatant was decanted off and the residue was washed sev-
eral times with pentane to afford a yellow oil. Yield: 197 mg
(0.31 mmol, 69%). Ϫ 1H NMR (300 MHz, Ϫ15 °C, C2Cl4D2): δ ϭ
7.49 (m, 1 H, py), 7.29 (m, 1 H, py), 7.14 (m, 1 H, py), 7.00 (m, 2
cis/trans-HW(CO)2(NO)(Me2P-tert-Bupy)2 (19): Compound 19
was prepared in the same manner as described for 17 by using 18
(62 mg, 0.066 mmol) as the starting complex; (cis/trans ratio 20:80)
Yield: 30 mg (0.045 mmol, 69%). Ϫ MS (FAB); m/z (%): 645 [Mϩ H, py), 6.76 (m, 1 H, py), 6.67 (m, 1 H, py), 6.49 (m, 1 H, py),
Ϫ CH3] (35), 632 [Mϩ Ϫ CO] (25), 587 [Mϩ Ϫ 2 CO Ϫ CH3] (22). 1.53 (m, 6 H, PCH3), 1.33 (m, 12 H, PCH3). Ϫ 31P NMR
Ϫ NMR data (cis isomer): 1H NMR (300 MHz, CD2Cl2): δ ϭ
Ϫ0.35 (t, 1 H, JPH ϭ 27.2 Hz, JWH ϭ 33.3 Hz), other resonances
partially obscured by those of the trans isomer. Ϫ 31P NMR
(300 MHz, Ϫ15 °C, C2Cl4D2): δ ϭ Ϫ9.8 (d, JPP ϭ 25 Hz, JPW
ϭ
2
256 Hz), Ϫ48.2 (d, JPP ϭ 25 Hz, JPW ϭ 220 Hz). Ϫ 13C NMR
(300 MHz, Ϫ15 °C, C2D2Cl4): δ ϭ 213.0 (dd, JCP ϭ 5 ϫ 3 Hz,
2
2
2
(300 MHz, CD2Cl2): δ ϭ Ϫ15.3 (s, JPW ϭ 251 Hz). Ϫ NMR data CO), 208.2 (dd, JCP ϭ 5 ϫ 41 Hz, CO), 15.2 [m, P(CH3)2], 11.39
1
(trans isomer): H NMR (300 MHz, CD2Cl2): δ ϭ 7.7Ϫ7.2 (m, 4
[m, P(CH3)2]. Ϫ IR (CH2Cl2): ν˜ ϭ 2035 cmϪ1 (s), 1962 (s), 1635
H, py), 6.67 (m, 2 H, py), 2.00 (m, 12 H, PCH3), 1.35 (s, 18 H, (m). Ϫ MS (FAB); m/z (%): 548 [Mϩ] (50), 520 [Mϩ Ϫ CO] (22),
tBu), Ϫ1.42 (t, 1 H, JPH ϭ 25.4 Hz, JWH ϭ 31.2 Hz). Ϫ 31P NMR 492 [Mϩ Ϫ 2CO] (6).
(300 MHz, CD2Cl2): δ ϭ Ϫ11.4 (s, JPW ϭ 279 Hz). Ϫ 13C NMR
[W(CO)2(CH3CN)(NO)(Me2P-tert-Bupy)2][BF4] (23a): To a solu-
tion of [W(CH3CN)3(CO)2(NO)][BF4] (115 mg, 0.24 mmol) in
THF (5 mL) was added Me2P-tert-Bupy (125 mg, 0.9 mmol). After
stirring the reaction mixture for 3 h at 60 °C, hexane was added to
2
(500 MHz, CD2Cl2): δ ϭ 216.6 (t, JCP ϭ 7 Hz, CO), 38.2 (s,
CMe3), 30.1 [s, C(CH3)3], 15.3 [m, P(CH3)2].
cis,cis-[W(CO)(NO)(η2-Ph2Ppy)2][BF4] (20): A suspension of 9a
(100 mg, 0.11 mmol) in toluene (10 mL) was stirred at 100 °C while
precipitate a yellow oil. The supernatant solution was decanted off
1420
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422

New Nitrosyltungsten Complexes
FULL PAPER
2
and the residue was taken up in acetonitrile (2 mL). This solution
was stirred for 5 min and then the solvent was removed under high
vacuum. The residual yellow oil was taken up in dichloromethane
(2 mL) and precipitated once more by the slow addition of hexane.
The residue was finally taken up in toluene (5 mL), filtered through
Celite, and dried under high vacuum. Yield: 145 mg (0.185 mmol,
77%). Ϫ 1H NMR (300 MHz, [D8]toluene): δ ϭ 7.52 (m, 4 H, py),
6.96 (m, 2 H, py), 2.26 (s, 3 H, CH3CN), 1.70 (m, 12 H, PMe2), 1.26
(s, 18 H, tBu). Ϫ 31P NMR (300 MHz, [D8]toluene): δ ϭ Ϫ12.8 (s,
JPW ϭ 254 Hz). Ϫ 13C NMR (300 MHz, [D8]toluene): δ ϭ 208.9
(m, CO), 38.0 (s, CMe3), 30.1 [s, C(CH3)3], 13.4 [m, P(CH3)2], 2.8
(s, CH3CN). Ϫ IR (CH2Cl2): ν˜ ϭ 2308 cmϪ1 (w), 2040 (s), 1967
13C NMR (300 MHz, CD2Cl2): δ ϭ 205.6 (t, JCP ϭ 6 Hz, CO). Ϫ
IR (CH2Cl2): ν˜ ϭ 2008 cmϪ1 (w), 1961 (s), 1638 (m). Ϫ MS (FAB);
m/z (%): 867 [Mϩ Ϫ 2 CO] (11), 796 [Mϩ Ϫ I] (22), 768 [Mϩ Ϫ I
Ϫ CO] (46). Ϫ C36H28IN3O3P2W (923.34): calcd. C 46.83, H 3.06,
N 4.55; found C 46.42, H 3.13, N 4.52.
trans-W(HCO2)(CO)2(NO)(Ph2Ppy)2 (26): Carbon dioxide was
slowly bubbled through a solution of 9 (50 mg, 0.063 mmol) in
THF (4 mL) at room temperature. The colour of the solution
slowly changed from yellow to orange. After 30 min, it was concen-
trated to a volume of 1 mL and the product was precipitated by
adding diethyl ether. After washing with pentane, an orange pow-
der was obtained. Yield: 32 mg (0.039 mmol, 60%). Ϫ 1H NMR
(300 MHz, CD2Cl2): δ ϭ 8.80 (m, 2 H, py), 7.66Ϫ7.28 (m, 26 H,
Ph), 7.06 [s, 1 H, OC(O)H]. Ϫ 31P NMR (300 MHz, CD2Cl2): δ ϭ
(s), 1682 (m). Ϫ MS (FAB); m/z (%): 701 [Mϩ] (20), 660 [Mϩ
Ϫ
CH3CN] (18), 632 [Mϩ Ϫ CO Ϫ CH3CN] (28), 604 [Mϩ Ϫ 2 CO
Ϫ CH3CN] (87), 544 [Mϩ Ϫ 2 CO Ϫ CH3CN Ϫ NO Ϫ 2 CH3] (16).
Ϫ An unidentified phosphane impurity amounting to 5% could not
be removed; no elemental analysis was attempted (see text).
28.2 (s, JPW ϭ 299 Hz). Ϫ 13C NMR (300 MHz, CD2Cl2): δ ϭ
2
2
210.4 (t, JCP ϭ 5 Hz, CO), 166.39 [s, OC(O)H]. Ϫ IR (CH2Cl2):
ν˜ ϭ 2050 cmϪ1 (w), 1962 (s), 1622 (br.). Ϫ MS (FAB); m/z (%):
796 [Mϩ Ϫ OC(O)H] (18), [Mϩ Ϫ 2 CO] (45), 768 [Mϩ Ϫ CO Ϫ
[W(CO)2(CH3CN)(NO)(Me2P-tert-Bupy)2][TFPB] (23b): A mix-
ture of 23a (276 mg, 0.35 mmol) and Na[TFPB] (336 mg, OC(O)H] (70), [Mϩ Ϫ 2 CO Ϫ OC(O)H] (28).
0.38 mmol) was stirred for 45 min at room temperature. After evap-
trans-W{η2-(Z)-C(CO2Me)؍CH[C(O)OMe]}(CO)(NO)(Ph2Ppic)2
oration of the solvent in vacuo, the residue was extracted with
dichloromethane and the combined extracts were filtered through
Celite. Removal of the solvent from the filtrate left the product as
a yellow oil. Yield: 460 mg (0.294 mmol, 77%). Ϫ 1H NMR
(300 MHz, CD2Cl2): δ ϭ 7.74 (br., 8 H, Ph), 7.58 (br., 4 H, Ph),
7.43 (m, 4 H, py), 7.23 (m, 2 H, py), 2.20 (s, 3 H, CH3CN), 1.80
(m, 12 H, PMe2), 1.35 (s, 18 H, tBu). Ϫ 31P NMR (300 MHz,
CD2Cl2): δ ϭ Ϫ13.6 (s, JPW ϭ 254 Hz). Ϫ 13C NMR (300 MHz,
(27): To a solution of 12 (12 mg, 14.5 µmol) in [D8]THF (0.7 mL)
was added dimethyl acetylenedicarboxylate (2 µL, 15.5 µmol) and
the reaction was monitored by 1H-NMR spectroscopy. After 5 min
at room temperature, the reaction was complete and a dark-red
solution had been obtained. The solvent was evaporated in vacuo
and the residual solid was washed several times with diethyl ether
and pentane. Yield: 10 mg (10.6 µmol, 73%). Ϫ 1H NMR
(300 MHz, [D8]THF): δ ϭ 7.70 (m, 8 H, Ph), 7.47 (m, 2 H, py),
7.28 (m, 12 H, Ph), 7.22 (m, 2 H, py), 7.00 (m, 2 H, py), 6.89 (t, 1
3
CD2Cl2): δ ϭ 207.9 (m, CO), 171.1 (d, JCP ϭ 7 Hz, ipso-C, py),
1
162.3 (q, ipso-C, BPh4), 158.1 (d, JCP ϭ 34 Hz, ipso-C, py), 38.0
4
H, JPH ϭ 3.4 Hz, vinyl H), 2.92 (s, 3 H, OCH3), 2.86 (s, 3 H,
(s, CMe3), 30.1 [s, C(CH3)3], 14.2 [m, P(CH3)2], 4.0 (s, CH3CN). Ϫ
IR (CH2Cl2): ν˜ ϭ 2308 cmϪ1 (w), 2040 (s), 1967 (s), 1682 (m). Ϫ
MS (FAB); m/z (%): 701 [Mϩ] (20), 660 [Mϩ Ϫ CH3CN] (18), 632
[Mϩ Ϫ CO Ϫ CH3CN] (28), 604 [Mϩ Ϫ 2 CO Ϫ CH3CN] (87),
544 [Mϩ Ϫ 2 CO Ϫ CH3CN Ϫ NO Ϫ 2 CH3] (16). Ϫ
C58H51BF24N4O3P2W (1564.3): calcd. C 44.93, H 3.32, N 3.58;
found C 44.42, H 3.31, N 2.94.
OCH3), 2.41 (s, 6 H, pic-CH3). Ϫ 31P NMR (300 MHz, [D8]THF):
δ ϭ 31.7 (s, JPW ϭ 295 Hz). Ϫ 13C NMR (300 MHz, [D8]THF):
δ ϭ 245.8 (t, 2JCP ϭ 5 Hz, CO), 222.4 (t, 2JCP ϭ 10 Hz, α-vinyl C),
183.2 (s, COOMe), 179.3 (s, COOMe), 160.7 (t, 1JCP ϭ 30 Hz, ipso-
C, py), 53.8 (s, OCH3), 50.9 (s, OCH3), 24.5 (s, CH3); the vinylic
carbon signal is obscured by aromatic resonances. Ϫ IR (CH2Cl2):
ν˜ ϭ 1935 cmϪ1 (s), 1689 (m), 1595 (m). Ϫ MS (FAB); m/z (%): 938
[Mϩ] (2), 910 [Mϩ Ϫ CO] (5), 798 [Mϩ Ϫ MeO2CCϭCCO2Me]
trans-W(CO)(NO)(Ph2Ppy)2(η2-CH3CO2) (24): To a solution of 10
(30 mg, 0.038 mmol) in a mixture of dichloromethane (0.5 mL) and (25).
2-propanol (2 mL), acetic acid (0.2 mL) was added at Ϫ30 °C. The
trans,trans-WD(CO)2(NO)(Ph2Ppy)2 (28): To a solution of 10 (40
resulting mixture was allowed to warm to room temperature,
whereupon slow gas evolution was observed. After stirring for 30
min, the mixture was concentrated to a volume of 1 mL and the
product was precipitated by slowly adding pentane. After sub-
sequent washing with pentane, a red powder was obtained. Yield:
21 mg (0.025 mmol, 64%). Ϫ 1H NMR (500 MHz, CD2Cl2): δ ϭ
8.71 (m, 2 H, py), 7.60Ϫ7.20 (m, 26 H, Ph), 0.54 (s, 3 H, CH3). Ϫ
31P NMR (300 MHz, CD2Cl2): δ ϭ 39.3 (s, JPW ϭ 308 Hz). Ϫ 13C
NMR (500 MHz, CD2Cl2): Decomposition was observed when the
sample was left overnight. Ϫ IR (CH2Cl2): ν˜ ϭ 1894 cmϪ1 (s), 1578
(m). Ϫ MS (FAB); m/z (%): 827 [Mϩ] (2), 799 [Mϩ Ϫ CO] (3), 768
[Mϩ Ϫ CO(O)CH3] (18). Ϫ C37H31N3O4P2W (827.47): calcd. C
53.71, H 3.78, N 5.08; found C 52.67, H 3.56, N 5.18.
mg, 0.050 mmol) in dichloromethane, [D1]methanol (0.5 mL) was
added at 0 °C. After stirring for 1 h at exactly 0 °C, the deuterated
product was precipitated from the reaction mixture by adding fur-
ther [D1]methanol (3 mL). The solvents were decanted and the yel-
low solid was dried in vacuo. Yield: 35 mg (44 µmol, 88%). Ϫ 2H
NMR (300 MHz, CH2Cl2): δ ϭ Ϫ0.32 (br. s). Ϫ 31P NMR
(300 MHz, CD2Cl2): δ ϭ 31.0 (t, 2JPD ϭ 3 Hz). Ϫ IR (CH2Cl2): ν˜ ϭ
1921 cmϪ1 (s), 1628 (m); WϪD not observed. Ϫ C36H28DN3O3P2W
(798.45): calcd. C 54.15, H 3.53, N 5.26; found C 53.85, H 3.86,
N 5.27.
X-ray Structural Determinations: Data collection for all structures
was performed in
a cold N2 stream (see Table 1) with a
NicoletϪSiemens P4 diffractometer in the range 2.0° Յ ϕ Յ 25.0°.
The structures of complexes 9, 11, and 20 were solved by Patterson
synthesis (SHELXS-86)[25] and refined using SHELXTL-PLUS[26]
for 11 and 20 or SHELXL-93[27] for 9. The structure of complex
14 was solved by direct methods (SIR-92,[28] SHELXTL-PLUS).
Pertinent crystallographic parameters for the four structures are
listed in Table 1.
trans-IW(CO)2(NO)(Ph2Ppy)2 (25): To a solution of 10 (24 mg,
0.03 mmol) in dichloromethane (0.7 mL), hydroiodic acid
(0.05 mL, 0.75  in chloroform) was added at room temperature.
The colour of the solution changed from yellow to orange and gas
evolution was observed. After 10 min, the solvent was removed
under reduced pressure and the orange product was washed several
1
times with pentane. Yield: 19 mg (0.021 mmol, 69%). Ϫ H NMR
(300 MHz, CD2Cl2): δ ϭ 8.83 (m, 2 H, py), 7.7Ϫ7.2 (m, 26 H, Ph).
Ϫ
Crystallographic data (excluding structure factors) for the struc-
31P NMR (300 MHz, CD2Cl2): δ ϭ 13.0 (s, JPW ϭ 289 Hz). Ϫ tures reported in this paper have been deposited with the Cam-
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422
1421

H. Berke et al.
FULL PAPER
Table 1. Experimental conditions and crystallographic data for 9a, 11, 14, and 20
9a
11
14
20
Empirical formula
Molecular mass
Colour
C36H28BF4N3O3P2W
883.21
C38H32BF4N3O3P2WCH2Cl2
C45H44F6N3O4P3W
1081.62
yellow
0.15 ϫ 0.20 ϫ 0.35
monoclinic
P21/c
C37H32BCl4F4N3O2P2WCH2Cl2
996.23
yellow
0.25 ϫ 0.35 ϫ 0.40
monoclinic
P21/c
1025.7
yellow
red
Cryst. size [mm]
Cryst. system
Space group
0.2 ϫ 0.3 ϫ 0.3
monoclinic
P21/n
0.25 ϫ 0.35 ϫ 0.35
triclinic
¯
P1
˚
a [A]
17.051(6)
11.344(2)
18.515(3)
107.06
12.160(3)
10.521(4)
34.088(8)
96.23(2)
4335(2)
4
18.059(3)
11.760(3)
21.895(5)
96.52(2)
4691.9
12.870(3)
12.938(2)
13.161(3)
85.98(2)
2026.3(6)
2
˚
b [A]
˚
c [A]
β [°]
3
˚
V [A ]
3423.7(15)
4
Z
4
1.56
Dcalcd. [g/cm3]
Radiation
1.713
1.66
1.68
Mo-Kα
203
Mo-Kα
178
Mo-Kα
173
Mo-Kα
183
T [K]
No. of rflns. collected
No. of unique rflns.
wR2
7489
7615
7862
7110
5105
8503
5528
6899
0.101
0.600
0.520
0.360
R1
5.22
4.1
5.0
2.8
goodness-of-fit
1.192
1.153
1.037
1.147
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˚
to 0.006 hartree/A or hartree/radian, respectively. In the transition
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[22]
Acknowledgments
We thank Dr. T. Fox for advice on the NMR investigations and the
Swiss National Science Foundation for financial support.
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Received November 12, 1999
[I99403]
1422
Eur. J. Inorg. Chem. 2000, 1411Ϫ1422