4158 Organometallics, Vol. 20, No. 20, 2001
Persson et al.
Syn th esis of [Os3(CO)11(P H2P CH2CH2SMe)] (1). In a
typical reaction, the cluster [Os3(CO)11(NCMe)] (92 mg, 0.100
mmol) and Ph2PCH2CH2SMe (1; 26 mg, 0.100 mmol) were
dissolved in CH2Cl2 (10 mL) and stirred at room temperature
for ca. 2 h. The solvent was then removed under reduced
pressure at 40 °C. Ensuing purification by TLC (hexane/CH2-
Cl2, 1:1 v/v) afforded yellow [Os3(CO)11(Ph2PCH2CH2SMe)] (2;
72 mg, 63%). IR (hexane): (νCO) 2107 (m), 2055 (s), 2035 (m),
2020 (vs), 2002 (w), 1990 (m), 1976 (w), 1956 (vw). 1H NMR
(CDCl3, 300 MHz, 20 °C): δ 7.46-7.50 (m, 10H, Ph): 2.89 (m,
2H, PCH2), 2.29 (m, 2H, CH2S), 2.04 (s, 3H). 13C{1H} NMR
(CD2Cl2, 213K) 192.3 (d, 1C, J C-P ) 9.1 Hz), 184.7 (s, 1C), 183.3
(s, 1C), 175.9 (s, 1C), 175.6 (s, 1C), 172.1 (s, 1C), 171.7 (s, 1C),
169.4 (s, 1C). 31P{1H} NMR (CDCl3, 121 MHz, 293 K): -11.17
(s, 1P). FAB+ m/z 1140 (M+).
Syn t h esis of 1,2-[Os3(CO)10(µ-P h 2P CH2CH 2SMe)] (2).
Meth od I. The cluster [Os3(CO)10(NCMe)2] (93 mg, 0.100
mmol) and Ph2PCH2CH2SMe (26 mg, 0.100 mmol) were
dissolved in CH2Cl2 (10 mL) and stirred at room temperature
for 2 min. The solution was concentrated under reduced
pressure. Recrystallization of the crude product in a mixture
of CH2Cl2/n-hexane at -5 °C yielded orange crystals of 1,2-
[Os3(CO)10(µ-Ph2PCH2CH2SMe)], 2 (62 mg, 56%).
Con clu sion
The ligand Ph2PCH2CH2SMe coordinates to trinucle-
ar clusters as a monodentate phosphine or a bidentate
P,S ligand; in no case could coordination through only
the thioether moiety of the ligand be detected. When 2
equiv of Ph2PCH2CH2SMe are reacted with [Os3(CO)10-
(NCMe)2], both 1,2-[Os3(CO)10(µ-Ph2PCH2CH2SMe)] (2)
and [Os3(CO)10(Ph2PCH2CH2SMe)2] (3) were formed,
while only 2 could be detected when 1 equiv of the ligand
was used. 1,2-[Os3(CO)10(µ-Ph2PCH2CH2SMe)] is con-
verted into 1,1-[Os3(CO)10(Ph2PCH2CH2SMe)] (4) in an
isomerization reaction with low activation barrier;
kinetic studies indicate that the isomerization occurs
via an associative mechanism which is proposed to
involve a nucleophilic attack on an osmium atom by the
coordinated sulfur in 2. While both concerted and
nonconcerted thioether/carbonyl migration processes are
possible, we favor a concerted mechanism, as it will not
violate the EAN rule.
Meth od II. The oxidative reagent Me3NO (1.36 mg, 0.0181
mmol) was added as a solid to a solution of [Os3(CO)11(Ph2-
PCH2CH2SMe)] (20.6 mg, 0.0181 mmol) in CH2Cl2 (20 mL).
The reaction mixture was stirred at room temperature for
approximately 2 min and then concentrated under reduced
pressure. Recrystallization of the crude product in a mixture
of CH2Cl2/n-hexane yielded orange crystals of 2 (13 mg, 65%).
The compound was stable as a solid and could be stored for
several days at room temperature. Crystals of 2 suitable for
an X-ray diffraction study were grown from a CH2Cl2/n-hexane
solution at 4 °C. IR (hexane): ν(CO) 2093 m, 2060 w, 2055
vw, 2029 m-w, 2011 vs, 2006 vs, 1979 w, 1957 w cm-1. 1H NMR
(CDCl3, 300 MHz, 20 °C): 7.25-7.58 (m, 10H), 2.90 (m, 2H),
2.79 (s, 3H), 2.73 (m, 2H), 2.30 (m). 13C{1H} NMR (CD2Cl2,
213 K): 196.3 (s, 1C), 194.5 (s, 1C), 193.5 (s, 1C), 193.2 (s,
1C), 184.0 (s, 2C), 179.0 (s, 1C), 176.9 (s, 1C), 172.5 (s, 2C).
31P{1H} NMR (CDCl3, 121 MHz, 20 °C): -0.597 (s, 1P). Anal.
cf. compound 4.
P r ep a r a tion of [Os3(CO)10(P h 2P CH2CH2SMe)2] (3). The
cluster [Os3(CO)10(NCMe)2] (100 mg, 0.107 mmol) and Ph2-
PCH2CH2SMe (57 mg, 0.214 mmol) were dissolved in CH2Cl2
(20 mL) and stirred at room temperature for appproximately
2 h. The solution was concentrated under reduced pressure
and ensuing purification by TLC (hexane/CH2Cl2, 3:2 v/v)
yielded two fractions; they were, in order of increasing elution
rate, yellow [Os3(CO)11(Ph2PCH2CH2SMe)] (1; 61 mg, 55%) and
a second crude fraction. A second purification of the crude
fraction by TLC (thf/n-hexane 2:3) yielded two compounds;
they were, in order of increasing elution rate, red [Os3(CO)10(Ph2-
PCH2CH2SMe)2] and 1,1-[Os3(CO)10(Ph2PCH2CH2SMe)] (4, 23
mg, 0.021 mmol 20%). Data for 3: 37 mg, 0.027 mmol, 25%.
IR (CH2Cl2): ν(CO)/cm-1 2083 m, 2026 s, 1998 vs, 1964 s(br).
1H NMR (CDCl3, 300 MHz, 20 °C): 7.43-7.69 (m, 20H), 2.87-
2.89 (m, 4H), 2.27-2.29 (m, 4H), 2.02 (s, 3H). 31P{1H} NMR
(CDCl3, 121 MHz, 20 °C): -16.1 (s, 1P (br)), -12.8 (s, 1P (br)),
-11.8 s(br), 2P). FAB MS (m/z): obsd 1373 calcd 1372.
Syn t h esis of 1,1-[Os3(CO)10(P h 2P CH2CH 2SMe)] (4).
Meth od I. The cluster [Os3(CO)10(NCMe)2] (93 mg, 0.100
mmol) and Ph2PCH2CH2SMe (1; 26 mg, 0.100 mmol) were
dissolved in CH2Cl2 (10 mL) and stirred at room temperature
for appproximately 24 h. The solution was concentrated under
reduced pressure, and ensuing purification by TLC (hexane/
CH2Cl2, 3:2 v/v) yielded orange 1,1-[Os3(CO)10(Ph2PCH2CH2-
SMe)] (4; 61 mg, 55%).
Exp er im en ta l Section
Gen er a l P r oced u r es. Unless otherwise stated, purification
of solvents, reactions, and manipulation of compounds were
carried out under a nitrogen atmosphere with use of standard
Schlenk techniques. All solvents were dried by distillation over
the appropriate drying agents. The starting materials [Os3-
(CO)12- (NCMe)n] (n ) 1, 2)38 were prepared by literature
n
methods. All chromatographic separations and ensuing work-
up were carried out in open air. Thin-layer chromatography
was carried out on Merck 60 0.5 mm. Columns were packed
with Merck 60 (70-230 mesh ASTM) silica gel. Infrared
spectra were recorded as solutions in 0.5 mm NaCl cells on a
Nicolet 20SXC FT-IR spectrometer with carbon monoxide as
calibrant. Fast atom bombardment (FAB) mass spectra were
obtained on a J EOL SX-102 spectrometer using 3-nitrobenzyl
alcohol as matrix and CsI as calibrant. Proton and 31P NMR
spectra were recorded on a Varian Unity 300 MHz NMR
spectrometer. The 13C NMR spectra were recorded on a J EOL
EX400 spectrometer operating at 100.25 MHz. Microanalyses
were performed by Mikrokemi AB, Uppsala, Sweden.
Syn th esis of P P h 2CH2CH2SMe. Lithium wire (306 mg,
44 mmol) was added to a stirred solution of diphenylphosphine
chloride (3.7 mL, 20 mmol) in THF (100 mL). The solution was
then stirred at room temperature for ca. 20 h. The deep-red
mixture was transferred to a flask equipped with a dropping
funnel and cooled to -40 °C, and ethylene sulfide (1.18 mL,
20 mmol) in THF (10 mL) was added dropwise to the stirred
mixture. The reaction mixture became transparent and was
allowed to warm to room temperature over a period of 1 h. To
this solution, iodomethane (1.24 mL, 20 mmol) was added
dropwise during a period of ca. 5 min. After 2 h, the solvent
was removed in vacuo. The crude product was obtained as a
gray, semitransparent oil (5.12 g). A small fraction of the
substance (500 mg) was subjected to column chromatography
using a 4:3 hexane/dichloromethane mixture as eluent. Two
fractions were isolated; they were, in order of increasing
retention time, an unidentified colorless compound (48 mg) and
Ph2PCH2CH2SMe, (181 mg, 35%). The P,S ligand precipitated
as a white solid after storage at 5 °C for approximately 48 h.
1H NMR (CDCl3, 300 MHz, 20 °C): δ 7.35-7.45 (m, 10H, Ph),
2.57 (m, 2H, CH2), 2.35 (m, 2H, CH2), 2.12 (s, 3H, CH3). 31P-
{1H} NMR (CDCl3, 121 MHz, 20 °C): δ -16.7 (s, 1P). C, H, S,
P Anal. (Calcd): C, 69.20 (69.21); H, 6.40 (6.58); S, 12.20
(12.31); P, 12.20 (11.9).
Meth od II. The oxidative reagent Me3NO (1.36 mg, 0.0181
mmol) was added as a solid to a solution of [Os3(CO)11(Ph2-
PCH2CH2SMe)] (20.6 mg, 0.0181 mmol) in CH2Cl2 (20 mL).
The reaction mixture was stirred at room temperature until
(38) J ohnson, B. F. G.; Lewis, J .; Pippard, D. A. J . Chem. Soc.,
Dalton Trans. 1981, 407.