Transition metal complexes with sulfur ligands .114. Alkylation, substitution reactions, electrochemistry and structure of nitrosyl and carbonyl complexes with the [Mo('S-4')]fragment('S-4'(2-)=1,2-bis(2-mercaptophenylthio)ethane(2-))

Alkylation of [Mo(NO)(Cl)('S-4')] (1) ('S-4'(2-)=1,2-bis (2-mercaptophenylthio) ethane(2-)) by R(3)OBF(4) (R=Me, Et) yielded the mono alkyl derivatives [Mo(NO) (Cl) (R-'S-4')]BF4 (R=Me([2]BF4),Et([3]BF4)). NMR spectra indicated that in both cases the isolated species contained only one diastereomer. As indicated by nu(NO) frequencies, [2]BF, and [3]BF4 exhibit a lower electron density at the molybdenum centers, and they are reduced electrochemically at less negative potentials when compared to the parent compound [Mo(NO)(Cl)('S-4')] (1). Replacement of the chloro ligand in [Mo(NO) (Cl) ('S-4')] (1) by o-methylthiobenzenethiolate yielded the six-coordinate complex [Mo(NO)(SC6H4SCH3)('S-4')] (4), in which the CH3S group does not coordinate. When 4 was treated with HCl or PMe(3), the SC6H4SCH3 ligand dissociated and the parent compound 1 or the 17-electron complex [Mo(NO)(PMe(3))('S-4')] formed. Decarbonylation of yellow [Mo(CO)(3)('S-4')] (5) yielded [Mo(CO)(mu-'S-4')](2) (6) as a mixture of diastereomers. A centrosymmetric diastereomer of 6 with trans-coordinated CO ligands was characterized by X-ray structure analysis. Crystal data of [Mo(CO)(mu-'S-4')](2) . 2CH(2)Cl(2): rhombohedral space group R (3) over bar; a=31.138(5), b=31.138(5), c=12.152(5) A; Z=9; R/R(w)=6.1/6.1%. Each Mo center is surrounded by five S donors, one C atom, and the neighboring Mo center. The two enantiomeric [Mo(CO)((S-4')] fragments are linked to each other via an Mo=Mo double bond and two bridging thiolate donors. The thiolate donors within one metal fragment are coordinated trans to each other.