754 Organometallics, Vol. 18, No. 4, 1999
Vicente et al.
The brown-red suspension formed was stirred at room tem-
perature for 2 h and then concentrated to dryness. The residue
was extracted with dichloromethane (3 × 15 mL), and the
extracts were filtered through Celite. The solution was con-
centrated (5 mL) and diethyl ether (20 mL) added to precipitate
Na[AuBr4] (485 mg, 0.9 mmol) as a brown-red solid that was
filtered, washed with diethyl ether (2 × 5 mL), and suction
dried. Yield: 76%.
Ch a r t 1
Wa r n in g: Perchlorate salts with organic cations can be
explosive and should be prepared in small amounts.
The ligands py{SCH2C(O)R}-2 (R ) Me, OMe) have been
prepared following the procedure used for py{SCH2C(O)Ph}-
2.1
p y{SCH2C(O)Me}-2. 1H NMR (CDCl3, δ): 2.32 (s, 3 H, Me),
3.99 (s, 2 H, CH2), 6.96 [m, 1 H, H4 (py)], 7.21 [m, 1 H, H3
(py)], 7.49 (m, 1H, H5 (py)], 8.37 (m, 1H, H6 (py)]. IR (cm-1):
[AuBr{PPh2{C6H4(CH2CHdCH2)-2}}], respectively, while
[Au{N2C10H7(CH2CMe2)-6}Cl]17 results from the reac-
tion of Na[AuCl4] with 6-tert-butyl-2,2′-bipyridine. Very
ν
CO, 1706.
recently, the first auracyclobutan-3-one [Au{CH(CO2-
Me)C(O)CH(CO2Me)}L] and aurathietane-3,3-dioxide
p y{SCH2CO2Me}-2. 1H NMR (CDCl3, δ): 3.61 (s, 3 H,
OMe), 3.88 (s, 2 H, CH2), 6.86 [m, 1 H, H4 (py)], 7.09 [m, 1 H,
H3 (py)], 7.34 (m, 1H, H5 (py)], 8.26 (m, 1H, H6 (py)]. IR (cm-1):
[Au{CH{C(O)Ph}SO2CH{C(O)Ph}}L] [L ) C6H3CH2-
NMe2-2-OMe-5] complexes have been reported.11 They
are obtained by reacting the dichlorocomplex [Au(L)-
Cl2] with dimethyl-1,3-acetonedicarboxilate or diphen-
acyl sulfone, respectively, in the presence of silver oxide.
All cycloauration reactions described so far require
the refluxing of a solution of a gold(III) complex contain-
ing the substrate to be metalated as a ligand (usually
[AuCl3(LH)]) or the use of some additional basic reagent
to promote the metalation (usually a silver salt). Some-
times, both these reaction conditions are required. Here,
we describe the first cycloauration reactions that occur
at room temperature and without the need of any basic
promoter. In addition, we also show that better results
are obtained by using a different basic reagent, Na2-
CO3. This paper reports new cycloaurated complexes
ν
CO, 1738.
Syn th eses of [Au Cl2{p y{SCHC(O)R}-2}] [R ) P h (1a ),
Me(1b), OMe (1c)]. py{SCH2C(O)R}-2 (ca. 1 mmol), Na-
[AuCl4], and Na2CO3 were reacted in acetone (25 mL) in 2:2:1
molar ratio for 2.5 (1a ), 7 (1b), or 22 (1c) h, respectively. The
resulting suspension was concentrated to dryness, and the
residue was extracted with dichloromethane (5 × 50 mL) and
filtered through anhydrous MgSO4. Complexes 1a -c precipi-
tated as orange solids upon concentration of the solution (to
ca. 5 mL) and addition of diethyl ether (20 mL).
1a . Yield: 72%. Mp: 112 °C (decomp). ΛM: 12 Ω-1 cm2
mol-1. IR (cm-1): νCO, 1679; νAuCl, 358, 312. H NMR (CDCl3,
δ): 5.86 (s, 1 H, CHAu), 7.44-7.53 [m, 3 H, m-H (COPh) +
p-H (Ph)], 7.63 [m, 1 H, H5 (py)], 7.85 [m, 1 H, H3 (py)], 7.95
1
3
[m, 1 H, H4 (py)], 8.07 [d, 2 H, o-H (COPh), J HH ) 7.5 Hz],
9.26 [d, 1 H, H6 (py), J HH ) 6 Hz]. 13C{1H}: 59.17 (s, CHS),
3
98.56 [s, ipso-C (COPh)], 121.99, 123.06 [s, C4 (py) + p-C′
(COPh)], 128.75, 129.77 [s, o-C + m-C (COPh)], 134.48 [s, C5
(py)], 141.37 (s, C3 (py)], 150.26 [s, C6 (py)], 172.27 [s, C2 (py)],
191.2 (s, COPh). Anal. Calcd for C13H10AuCl2NOS: C, 31.47;
H, 2.03; N, 2.82; S, 6.46. Found: C, 31.32; H, 2.07; N, 3.05; S,
6.63.
involving a C(sp3)-Au(III) bond, [Au{py{SCHC(O)R}-
2}], and is a part of a series dedicated to the study of a
family of ligands that can coordinate through nitrogen,
sulfur, or oxygen and, after a C-H bond activation,
through the methylene carbon atom or a carbon atom
of the group R (see Chart 1). We call these multidonor
ligands. We have previously reported1 some mono-, di-,
and trinuclear silver(I) and gold(I) derivatives of 2-phen-
acylthiopyridine showing the different coordination
affinity of these cations toward the sulfur and nitrogen
atoms.1
1b. Yield: 58%. Mp: 120 °C (decomp). ΛM: 0 Ω-1 cm2 mol-1
.
IR (cm-1): νCO, 1697; νAuCl 354, 305. 1H NMR (CDCl3, δ): 2.47
(s, 3 H, Me), 5.05 (s, 1 H, CHAu), 7.40 [t, 1 H, H4 (py)], 7.81-
7.99 [m, 2 H, H3 + H5 (py)], 9.21 [d, 1 H, H6 (py), J HH ) 8.6
Hz]. Anal. Calcd for C8H8AuCl2NOS: C, 22.13; H, 1.86; N, 3.23;
S, 7.39. Found: C, 22.33; H, 1.71; N, 3.22; S, 7.63.
3
1c. Yield: 49%. Mp: 105 °C. ΛM 6 Ω-1 cm2 mol-1. IR (cm-1):
1
νCO, 1733; νAuCl, 362, 273. H NMR (CDCl3, δ): 3.78 (s, 3 H,
Me) 3.96 (s, 1 H, CH), 7.57 [t, 1 H, H4 (py)] 7.95-8.06 [m, 2
Exp er im en ta l Section
3
H, H3 + H5 (py)], 8.58 [d 1 H, H6 (py), J HH ) 6.3 Hz]. Anal.
Calcd for C8H8AuCl2NO2S: C, 21.35; H, 1.79; N, 3.11; S, 7.12.
Found: C, 21.10; H, 1.89; N, 2.92; S, 6.50.
The IR spectra, elemental analyses, conductance measure-
ments in acetone, and melting-point determinations were
carried out as described earlier.38 A Varian Unity-300 spec-
trometer was used to record 1H, 13C{1H}, and 31P{1H} NMR
spectra. Chemical shifts are referred to TMS [1H, 13C{1H}] or
H3PO4 [31P{1H}]. Otherwise stated the reactions were carried
out at room temperature without special precautions against
moisture. 2-Mercaptopyridine (HSpy) and chloroacetone were
purchased from Fluka, 2-bromoacetophenone [BrCH2C(O)Ph]
from Aldrich, methylchloroacetate from Merck, and Na[AuCl4]
from Sociedad Espan˜ola de Metales Preciosos (SEMPSA). Na-
[AuBr4] was prepared by reacting Na[AuCl4] (450 mg, 1.18
mmol) in acetone (15 mL) with NaBr (731 mg, 7.11 mmol).
Syn th esis of [Au Br 2{py{SCHC(O)P h }-2}] (2a). py{SCH2C-
(O)Ph}-2 (425 mg, 1.85 mmol), Na[AuBr4] (1 g, 1.85 mmol),
and Na2CO3 (265 mg, 0.93 mmol) were reacted in acetone (10
mL) in 2:2:1 molar ratio for 1.5 h, and the resulting suspension
was concentrated to dryness. The oily residue was dried in
vacuo for 1 h and vigorously stirred with cold n-pentane (5
mL, 0 °C) for 0.5 h to give a solid that was filtered and dried
under a nitrogen stream to give 2a as a brick-red solid. Yield:
478 mg, 46%. Mp: 123 °C. ΛM: 0 Ω-1 cm2 mol-1. IR (cm-1):
ν
CO, 1651; νAuBr, 251, 219. 1H NMR (CDCl3, δ): 5.99 (s, 1 H,
CHAu), 7.41-7.54 [m, 3 H, m-H + p-H (COPh), 7.62 [m, 1 H,
H5 (py)], 7.86 [m, 1 H, H3 (py)], 7.96 [m, 1 H, H4 (py)], 8.06
3
(37) Bennett, M. A.; Hoskins, K.; Kneen, W. R.; Nyholm, R. S.;
Hitchcock, P. B.; Mason, R.; Robertson, G. B.; Towl, A. D. C. J . Am.
Chem. Soc. 1971, 93, 4591.
(38) Vicente, J .; Chicote, M. T.; Lagunas, M. C.; J ones, P. G. J . Chem.
Soc., Dalton Trans. 1991, 2579.
[d, 2 H, o-H (COPh), J HH ) 8.1 Hz], 9.41 [d, 1 H, H6 (py),
3J HH ) 6.1 Hz]. Anal. Calcd for C13H10AuBr2NOS: C, 26.69;
H, 1.72; N, 2.39; S, 5.48. Found: C, 26.82; H, 1.76; N, 2.46; S,
5.47.