Heavy Group 15 Element Compounds of a Sterically Demanding Bis(iminophosphorane)methanide and -methanediide

Complexes of the heavy pnictogen elements Sb and Bi of monoanionic (C,N-chelated: Sb, Bi) and dianionic (N,C,N-pincer type: Bi) bulky substituted bis­(diphenyl­(arylimino)­phosphorano)­methane H2C­(Ph2PNR)2 (R = 2,6-diisopropylphenyl (dipp)) have been prepared via metathetical reactions, and tautomerism within the monoanionic ligand backbone has been observed. The complexes have been characterized by means of X-ray analysis and NMR studies. The dianionic complex was found to feature the rare structural motif of a formal carbon–bismuth­(III) double bond. The molecular structure of the solvate-free potassium salt K­[HC­(Ph2PNdipp)2] is reported.