Reply to Réplique: A New Concept for Bonding in Carbodiphosphoranes?

Abstract

Neither is the synthesis of a molecule a mere technical conformation of a theoretical prediction, nor is a quantum chemical investigation a mere supplement to experimental work—the two sides rather complement each other. The theoretical study in question has shown that more compounds of the general formula EL2 with donor–acceptor bonds may exist which await synthesis.

N-Heterocyclic Carbene Adducts of Main Group Elements and Their Use as Ligands in Transition Metal Chemistry

“…Carbodicarbenes (CDC) of the type [(NHC) 2 C] were studied theoretically in several papers by Frenking and co-workers. − The electronic situation resembles that of long-known carbodiphosphoranes, − and these compounds exhibit lone pairs of π and σ symmetry, potentially available for metal coordination. This is illustrated by the mesomeric structures shown above in Chart .…”

Study of Beryllium, Magnesium, and Spodium Bonds to Carbenes and Carbodiphosphoranes

“…Apart from carbenes, an equally important and interesting group of organic compounds is the so-called carbodiphosphoranes (CDPs) and their amine analogues [ 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 ]. Their uniqueness in the electronic structure (see Figure 1 ) is that, unlike the previously described carbenes, in CDPs, none of the four valence electrons of the carbon atom participate in ligand binding, and therefore these electrons remain unbound.…”

Flexibility of the Carbodiphosphorane, (Ph3P)2C: Structural Characterization of a Linear Form

“…Carbodiphosphoranes, (R 3 P) 2 C, − which were first reported in 1961, constitute an interesting class of molecules that feature two-coordinate carbon (Figure ). In this regard, carbodiphosphoranes are structurally related to carbenes but differ by virtue of the fact that the carbon atoms of carbodiphosphoranes are formally zerovalent with two lone pairs, , whereas the carbon atoms of carbenes are divalent with one lone pair. , The presence of the lone pairs is manifested by carbodiphosphoranes being effective ligands for a variety of metals and nonmetals. ,− Furthermore, since there are two lone pairs, carbodiphosphoranes may coordinate to two metals .…”