New ligand substitution modes of M2(μ-SR)2(CO)8 (M=Mo, W; R=alkyl, aryl): synthesis, structure and properties of new di-nuclear metal(I) carbonyl thiolates, [M2(μ-SPh)2(CO)xLy]n− (M=Mo, W; x=6, 8; y=0, 1; L=PhS, (Ph)2PCH2P(Ph)2 and S2CNEt2; n=1, 0) and a

Reaction of [M2(SC6H5)2(CO)8] (M=Mo, W) with NaSR (SR=SC6H5, S2CNEt2) in the presence of tetra-alkylammonium halide, or with diphenylphosphinemethane (DPPM=(C6H5)2P CH2P (C6H5)2) in certain solvents affords new dinuclear metal(I)-carbonyl thiolates, [W2(SC6H5)2(CO)8] (1), [Et4N][Mo2(SC6H5)3(CO)6] (2), [Bu4N][Mo2(SC6 H5)2(CO)6(S2CNEt2)] (3), [W2(SC6H5)2(CO)6DPPM] (4) and polymer [W2(SC6H5)2(CO)6 DPPM]m (5). The crystal structures of 1, 2, 3 and 4 reveal that 1 contained a planar [W2S2] unit, 2 had a [Mo2S3] core with a planar Mo2S2 unit coordinated by a third SC6H5 bridging ligand and 3 and 4 possessed a planar [M2S2] (M=Mo, W) core with two M atoms in different coordination environments. Three ligand substitution modes in the complexes were found: (i) substitution took place on the two M atoms in cis-direction resulting in three bridging ligand compound (for 2); (ii) substitution occurred on one metal atom leading to unsymmetrical M2S2 unit (for 3 and 4); and (iii) substitution occurred on the two M atoms in trans-direction to form a polymer (for 5). IR, NMR and CV of these complexes were measured. An existence of mixed valence metal atoms leading to charge transfer and alteration of electrochemical behavior for the complexes were discussed and the possible structure of polymer compound 5 was proposed.