Synthesis and reactions with alkynes of complexes containing both phosphorus and sulfur bridging ligands: crystal and molecular structures of [Mn2(µ-PPh2)(µ-SPh)(CO)8], [CO3(µ3-S)(µ-PPh2)(CO)6(PPh3)] and [CO3(µ3-S)(µ-PPh2CHCPh)(CO)6(PPh3)]

Abstract

The metal carbonyls [Mn₂(CO)₁₀] and [Co₂(CO)₈] react with the ligand PPh₂(SPh) to give respectively the binuclear complex [Mn₂(µ-PPh₂)(µ-SPh)(CO)₈]2 and a combination of trinuclear complexes [Co₃(µ₃-S)-(µ-PPh₂)(CO)₇]3, [Co₃(µ₃-S)(µ-PPh₂)(CO)₆(PPh₃)]4 and [Co₃(µ₃-S)(µ-PPh₂)(CO)₅(PPh₃)₂]5 in a yield ratio which depends on the reaction conditions. Complex 4 reacts thermally with PhCCH which inserts regiospecifically into the phosphido-bridge to generate [Co₃(µ₃-S)(µ-PPh₂CHCPh)(CO)₆(PPh₃)]6. A similar regiospecific insertion of alkyne to give the complex [Fe₂{µ-PPh₂CHC(CH₂OH)}(µ-SPh)-(CO)₆]7 takes place when [Fe₂(µ-PPh₂)(µ-SPh)(CO)₆]1 is treated with HOCH₂CCH under photolytic conditions. In contrast neither thermal nor photolytic reactions of 2 with alkynes could be induced. The crystal structures of 2, 4 and 6 have been determined.