About C Ligands in Transition Metal Complexes

MORE ABOUT C LIGANDS IN TRANSITION METAL COMPLEXES 

A tricoordinated carbon center acting as a ligand to a transition metal is a powerful a donor because of the high energy of its valence (spn) orbital, and it is not a n acceptor. 

A dicoordinated carbon atom bonded to a metal may vary greatly in its n acceptor ability. If the atom is formally bonded by bond to another atom, the n acceptor ability ranges from poor to moderate depending upon whether the other atom is C (i.e., 

---

The borole ring and various 1,3-diborolyl anions have been extensively employed as ligands to prepare a huge array of transition metal complexes and multidecker sandwich compounds.96 97 Inevitably, the electronic character of the borole is profoundly changed upon complexation, so a study of such complexes can reveal nothing certain about B—C multiple bonding in the isolated ligand. 

Insertion of CSj in metal-hydride bonds gives metal dithioformates. Bonding of the ligands to the metal can take place in several ways (a) ionic in alkali and alkaline earth metal compounds (b) symmetric bidentate in most of the transition metal complexes and (c) as a positive symmetrically bonded ligand to (25), in which the HC(S)S has donated two electrons to the two electron-deficient dicarbanonaborane groups.36 Little is known about monothioformic acid and its complexes. 

---