Nature of the Heavy Formal Double Bonds As=Ch, Sb=Ch and Bi=Ch (Ch = S, Se, Te) in NCN-Pincer Supported Arsinidene, Stibinidene and Bismuthinidene Chalcogenides

The synthesis of an arylpnictinidenes 2,6-(Ph2PNMes)2C6H3Pn based upon a novel bis(phosphine imine) NCN-pincer ligand is reported (Pn = As, Sb, Bi). The oxidation of 2,6-(Ph2PNMes)2C6H3Pn with sulfur, selenium and tellurium, respectively, afforded arylarsinidene chalcogenides 2,6-(Ph2PNMes)2C6H3AsCh, arylstibinidene chalcogenides 2,6-(Ph2PNMes)2C6H3SbCh and arylbismuthinidene chalcogenides 2,6-(Ph2PNMes)2C6H3SbCh, which can be formulated as containing terminal Sb=Ch and Bi=Ch double bonds. Based on the complementary bonding analysis, the bonding situation is best described in terms of bipolar +Pn–Ch– single bonds (Ch = S, Se, Te).