Benzimidazole-functionalized PEPPSI type Pd(II)NHC complexes bearing nitrophenylethyl and hidroxyphenylethyl group: Synthesis, characterization, crystal structure and it's catalytic activity on direct arylation reaction

Abstract

This study contains synthesis, characterization, crystal structure, and catalytic activity of the new two series PEPPSI (Pyridine Enhanced Precatalyst Preparation, Stabilization and Initiation) type Pd(II)NHC complexes nitrophenylethyl and hidroxyphenylethyl groups. All complexes were prepared from the nitrophenylethyl and hidroxyphenylethyl substitute benzimidazolium salts, palladium chloride (PdCl2) and 3-chloropyridine. The structures of all PEPPSI type Pd(II)NHC complexes have been fully characterized by using NMR (1H and 13C), FTIR spectroscopic method, and elemental analysis techniques. Also, the single-crystals of four of these complexes were examined by utilizing by the X-ray diffraction method. Also, the catalytic activity of the nitrophenylethyl and hidroxyphenylethyl substituted benzimidazole-functionalized PEPPSI type Pd(II)NHC complexes on the direct arylation reaction were examined. It has been observed that among these complexes, those bearing electron-donor groups (hydroxyphenylethyl) are more active catalysts than those bearing electron-withdrawing groups (nitrophenylethyl) for direct arylation reactions.