Diphosphanyl‐ and Diarsanyl‐Substituted Carbene Homologues: Germanediyls, Stannanediyls, and Plumbanediyls with Remarkable Electronic Structures

The unusual, deep green color of the crystalline, stable singlet carbene homologues 1–4 reflects the significant destabilization of the HOMOs relative to those of other known homologues. Compounds 1–4 are monomeric both in the solid state and in solution, not least because surprisingly, no donor–acceptor interactions are formed between the F atoms of the sterically demanding groups R1 and the electron-deficient metal centers E. R1 = Si(2,4,6-iPr3C6H2)2F, Si(tBu)(2,4,6-iPr3C6H2)F; R2 = SiiPr3.