Ruthenium complexes of chelating amido-functionalized N-heterocyclic carbene ligands: Synthesis, structure and DFT studies

Abstract

Synthesis, structure and density functional theory (DFT) studies of a series of new ruthenium complexes, [1-(R)-3-N-(benzylacetamido)imidazol-2- ylidene]RuCl(p-cymene) [R = Me (1c), i-Pr (2c), CH2Ph (3c); p-cymene = 4-i-propyltoluene] supported over N/O-functionalized N-heterocyclic carbene (NHC) ligands are reported. In particular, the ruthenium (1-3)c complexes were synthesized from the respective silver complexes, [1-(R)-3-N-(benzylacetamido) imidazol-2-ylidene]2Ag+Cl- [R = Me (1b), i-Pr (2b), CH2Ph (3b)] by the treatment with [Ru(p-cymene)Cl2]2 in 65-76% yields. The molecular structures of (1-3)c revealed the chelation of the N-heterocylic carbene ligand through the carbene center and an amido sidearm of the ligand in all of the three complexes. The density functional theory studies on the ruthenium (1-3)c complexes indicated strong binding of the NHC ligand to the metal center as was observed from the deeply buried NHC-Ru s-bonding molecular orbitals. © Indian Academy of Sciences.