Cationic PCP and PCN NHC Core Pincer-Type Mn(I) Complexes: From Synthesis to Catalysis

The coordination chemistry of NHC core pincer-type PCP and PCN ligands with a Mn(I) center was systematically investigated. reaction [Mn(CO)5Br] free carbenes, conveniently prepared from the corresponding imidazolium salts strong base, leads to initial formation bidentate fac-[MnBr(CO)3(κ2P,C,L)] complexes bearing pending phosphine or pyridine donor extremity (L), which upon bromide abstraction, afford cationic [Mn(CO)3(κ3P,C,L)](OTf) derivatives exhibiting meridional facial coordinating geometry tridentate ligand depending on its relative flexibility. All bi- were characterized by X-ray diffraction analysis. impact structure catalytic performance illustrated in Mn-catalyzed hydrogenation acetophenone revealing fac-[Mn(CO)3(κ3P,C,N)](OTf) based 5,6-membered metallacyclic architecture be most active, thus evidencing role arm lability cycle.