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 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)2C6H3BiCh, which can be formulated as containing terminal As[double bond, length as m-dash]Ch, Sb[double bond, length as m-dash]Ch and Bi[double bond, length as m-dash]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).