The synthesis of new group 9 metal complexes containing the P
,S-chelate ligands
P,S-[SC
2B
10H
10(CH
2)
nPPh
2] (
n = 0, Cab
P,S (
2a);
n = 1, Cab
CH2P,S (
2b)) is described. Two newphosphinothiolato complexes of the type [M(Cab
P,S)(cod)] (M = Rh (
3a), Ir (
3b); cod = 1,5-cyclooctadiene) have been synthesized by the reaction of chloride-bridged dimers [M(
-Cl)(cod)]
2 with 2 mol equiv of the corresponding lithium phosphinothiolato ligand LiCab
P,S (
2a).The X-ray crystal structure determination of
3 shows a mononuclear, square-planar
cis-P
,Smetal complex with a cod ligand. Carbonylation of the cod complexes
3 yields the dinuclearcomplexes [M(
-
S-Cab
P,S)(CO)]
2 (where M = Rh (
4a), Ir (
4b)). The molecular structures revealthat the two metal atoms are bridged by the two thiolato ligands, and the carbonyls completethe coordination of the metal atoms. Dinuclear complexes
4 were also formed upon reactionof carbonyl dimers [M(
-Cl)(CO)
2]
2 with 2 equiv of
2a. Addition reactions of the dinuclearcomplexes
4 with triethylphosphine give the monosubstituted mononuclear metal complexes[M(Cab
P,S)(CO)(PEt
3)] (where M = Rh (
5a), Ir (
5b)), which are obtained as trans isomers.The molecular structure of complex
5a has been determined by X-ray diffraction methods.In an analogous manner, reaction of
2b with [Rh(CO)
2(acac)] (acac = acetylacetone) producesa dinuclear thiolato-bridged complex, [Rh(
-
S-Cab
CH2P,S)(CO)]
2 (
6). Complex
6 was characterized by single-crystal X-ray analysis. Reacting
6 with 2 equiv of PEt
3 gave the trans-phosphinoP,S-chelate complex [Rh(Cab
CH2P,S)(CO)(PEt
3)] (
7), analogous to
5. The mono- and dinuclearP,S-chelates
4 and
5 catalyze the carbonylation of methanol to acetic acid. In particular,the dinuclear rhodium carbonyl complex
4a is much more effective in catalyzing thecarbonylation of methanol to acetic acid than the previously known catalyst [RhI
2(CO)
2]
-.