Carbodicarbenes—divalent carbon(0) compounds exhibiting carbon–carbon donor–acceptor bonds

Theoretical and experimental studies of the recently introduced class of divalent carbon(0) compounds CL 2 , wherein L is a carbene ligand, are described. Carbodicarbenes posses two donor–acceptor bonds between carbene ligands and a bare carbon atom that retains its four valence electrons as two lone pairs. Carbodicarbenes R 2 C → C ← CR 2 are very strong Lewis bases. They are σ‐ and π‐donors and thus may bind to two Lewis bases.