Article
Organometallics, Vol. 29, No. 23, 2010 6415
degassed water (200 mL) four times, filtered through a pad of
alumina, and concentrated in vacuo to afford a viscous oil that
when taken up in Et2O and concentrated again afforded 7.0 g of
11 as a white powder in 70% yield. NMR analysis reveals a 1:1
mixture of diastereomers. 1H NMR (300 MHz, C6D6):41 δ 5.31
(d, J = 224 Hz, 2H, ArPH(C6H5)), 5.44 (d, J = 223 Hz, 6H,
ArPH(C6H5)), 6.85-7.00 (m, 14H, aryl-, rac/meso), 7.04-7.18
(m, 14H, aryl-H, rac/meso), 7.24-7.34 (m, 6H, aryl-H, rac/
meso), 7.34-7.42 (m, 4H, aryl-H, rac/meso), 7.48-7.59 (m, 4H,
aryl-H, rac/meso). 31P{1H} NMR (121 MHz, C6D6): δ -44.54
(d, J = 227 Hz), -43.85 (d, J = 224 Hz). HRMS (FABþ)
C29H24NP2: calcd mass 448.1384, measured mass 448.1371.
(PNP)K2 (12a). In an oven-dried 50 mL round-bottom flask
equipped with a stir bar and charged with 11 (500 mg, 1.1 mmol,
1.0 equiv) was added THF (5 mL). The clear solution was cooled
to -40 ꢀC, after which KBn (290 mg, 2.2 mmol, 2.0 equiv)
dissolved in cold THF (2 mL) was added dropwise. The dark red
solution was warmed to ambient temperature and concen-
trated in vacuo to approximately 1 mL for growth of red
crystals of 12b by slow evaporation of THF into toluene. For
quantitative isolation, the THF solution is completely evapo-
rated, washed with pentane, and dried in vacuo to afford 0.58 g
of the dipotassium salt as a red powder, which was stored at
Table 2. Crystal and Refinement Data for Complexes 12 and 13
12
13
empirical formula
formula wt
T (K)
C
82H90K4N2O6P4 C33H33N3P2Zr 1/4C6H6
3
1479.84
210(2)
644.31
100(2)
8.1980(9)
33.236(4)
23.311(2)
90
96.280(6)
90
6313.4(12)
8
monoclinic
P21/n
1.356
1.23-25.35
0.477
semiempirical from equiv
2.255
0.0505, 0.0734
˚
a (A)
10.1565(12)
11.1467(11)
17.888(2)
85.015(5)
87.679(5)
77.118(5)
1966.6(4)
1
triclinic
P1
1.250
2.06-26.22
0.360
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
cryst syst
space group
dcalcd (g/cm3)
θ range (deg)
μ (mm-1
abs cor
GOF
)
TWINABS
1.627
R1,a wR2b (I > 2σ(I)) 0.0560, 0.0867
P
P
P
P
a R1 = ||Fo|- |Fc||/ |Fo|. b wR2 = [ [w(Fo2 - Fc2)2]/ [w(Fo2)2]1/2
.
X-ray Crystal Data: General Procedure. Crystals grown from
THF (12a) and toluene (13) were removed quickly from a
scintillation vial to a microscope slide coated with Paratone N
oil. Samples were selected and mounted on a glass fiber with
Paratone N oil. Data collection was carried out on a Bruker
1
-15 ꢀC. H NMR (300 MHz, d8-THF): δ 6.44 (td, J = 7.2,
1.2 Hz, 2H), 6.57-6.73 (m, 6H), 6.85 (t, J = 15.1 Hz, 4H), 7.35
(d, J = 7.6 Hz, 2H), 7.42-7.53 (m, 4H), 7.69 (t, J = 7.6 Hz, 1H),
7.72 (d, J = 7.9 Hz, 2H). 31P{1H} NMR (121 MHz, d8-THF):
δ -14.35 (s).
˚
KAPPA APEX II diffractometer with a 0.710 73 A Mo KR
(PNP)Zr(NMe2)2 (13). An oven-dried 50 mL round-bottom
flask equipped with a stir bar was charged with bis(phosphine)
11 (57 mg, 130 μmol, 1.0 equiv) and Zr(NMe2)4 (34 mg,
130 μmol, 1.0 equiv). Benzene (5 mL) was vacuum-transferred
at 0 ꢀC, and the solution was stirred rapidly while being warmed
to ambient temperature. After 5 min of stirring at room tem-
perature, the dark red solution was concentrated in vacuo to
afford a red oil. Pentane was then vacuum-transferred onto the
oil, and the pink suspension was concentrated in vacuo to afford
80 mg of a pink solid in quantitative yield. Crystals suitable for
source. The structures were solved by direct methods. All non-
hydrogen atoms were refined anisotropically. Some details regard-
ing refined data and cell parameters are available in Table 2 and in
the Supporting Information. Selected bond distances and angles
are supplied in the captions of Figures 3 and 4.
Computational Details. Density functional calculations were
carried out using Gaussian 03 Revision D.01.46 Calculations
were performed using the nonlocal exchange correction by
Becke47,48 and nonlocal correlation corrections by Perdew,49
as implemented using the b3lyp50,51 keyword in Gaussian. The
following basis sets were used: LANL2DZ52-54 for Zr atoms
and 6-31G** for all other atoms. Pseudopotentials were utilized
for Zr atoms using the LANL2DZ ECP. All optimized struc-
tures were verified using frequency calculations and did not
contain any imaginary frequencies. Isosurface plots were made
using the Visual Molecular Dynamics program.55
1
X-ray analysis were obtained in toluene at -35 ꢀC. H NMR
(300 MHz, C6D6): δ 2.64 (s, Zr(N(CH3)2)2, 12H), 6.66 (d, J =
7.9 Hz, 2H), 6.70 (td, J= 7.5, 1.2 Hz, 2H), 6.88 (td, J= 7.7, 1.4 Hz,
2H), 6.95 (ddd, J = 7.5, 2.8, 1.3 Hz, 2H), 7.09-7.01 (m, 3H), 7.18
(t, J = 7.9 Hz, 4H), 7.47 (dd, J = 7.5, 2.8 Hz, 2H), 7.70 (t, J =
6.6 Hz, 4H). 31P{1H} NMR (121 MHz, C6D6): δ 0.00 (br s).
Variable-Temperature NMR Procedure. All variable-tempera-
ture NMR experiments were performed on a Varian INOVA-500
spectrometer. An oven-dried J. Young NMR tube was charged
with 7 mg of 11. On a high-vacuum-line setup, the tube was
evacuated and 1.2 mL of tetrachloroethane-d2 was vacuum-
transferred onto the solid. The solution was then blanketed in
argon and sealed. The desired temperature of the NMR probe
was set, and after reaching said temperature, the temperature
of the tube was allowed to stabilize for 15 min before acquiring
a spectrum.
Acknowledgment. We thank Taylor N. Lenton, Yuxiao
Sun, and Ian A. Tonks for helpful discussions and for
comparisons to their unpublished results. DFT calculations
were carried out using the Molecular Graphics and Com-
putation Facility, College of Chemistry, University of
California, Berkeley, CA, with equipment support from
NSF Grant CHE- 0233882. We gratefully acknowledge the
support of the KAUST Center-In-Development at King
Fahd University of Petroleum and Minerals (Dhahran,
Saudi Arabia) and the USDOE Office of Basic Energy
Sciences (Grant No. DE-FG03-85ER13431). We thank
Lawrence M. Henling and Michael W. Day of Caltech for
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