Synthesis and Structure of [(CO)₄Mn{(PPh₂)₂C−S₆−C(PPh₂)₂}Mn(CO)₄]: A Unique Tetraphosphinobis(methanide) Complex of Manganese(I) with a Hexasulfur Bridge

Nucleophilic degradation of cyclo-octasulfur by the diphosphinomethanide derivative [Mn(CO)₄{(PPh₂)₂CH}] (2) yields [(CO)₄Mn{(PPh₂)₂C−S₆−C(PPh₂)₂}Mn(CO)₄] (3), a complex containing the first example of a hexasulfur-bridged tetraphosphinobis(methanide) ligand. In the molecular structure of 3, determined by a single-crystal X-ray structural analysis, the conformation of the C−S₆−C chain may be regarded as arising from an opened S₆ ring, with terminal groups attached in trans positions.