Transition metal complexes with sulfur ligands Part CVII. Complexes of the [Mo(NO)(‘S 4’)] fragment with 16, 17 and 18 valence electrons (‘S 4’ 2−=1,2-bis(2-mercaptophenylthio)ethane(2−))

Abstract

Redox-substitution reactions of [Mo III(SPh)(NO)(‘S 4’)] ( 4) with phosphines yielded the mononuclear and paramagnetic 17-electron complexes [Mo II(PR 3)(NO)(‘S 4’)] (PR 3=PMe 3 ( 5), PEt 3 ( 6), PPr 3 ( 7) and PMe 2Ph ( 8)), exhibiting weil resolved EPR spectra. The molecular structure of 5 was determined by X-ray structure analysis. 5 crystallizes in space group R 3 with a=2586.6(5), c=1756.4(4) pm, Z=18, shows pseudo-octahedral coordination of the Mo center, and exhibits no anomalies in distances and angles in comparison with other [Mo(L)(NO)(‘S 4’)] complexes. The ability of all 17-electron [Mo(PR 3)(NO)(‘S 4’)] complexes to take up or release one electron to give 18- or 16-electron species was proved by cyclovoltammetry. Attempts to generate the resulting [Mo(PMe 3)(NO)(‘S 4’)] −/+ anions or cations by chemical redox reagents led to products which could not be characterized unambiguously. Isolable 16-electron species which could be fully characterized were obtained by oxidation of 5 with Cl 2, Br 2 and I 2 yielding [Mo III(X)(NO)(‘S 4’)] (X=Cl ( 3), Br ( 10), I ( 11)). 10 and 11 were also obtained by treatment of either the chloro complex [Mo(Cl)(NO)(‘S 4’)] ( 3) or the hydroxylaminyl complex [Mo(NH 2O)(NO)(‘S 4’)] ( 2) with HBr and HI. Reaction of 5 with NO gave the 18-electron complex [Mo(NO) 2(‘S 4’)] (1).