Synthesis and characterization of new chiral octadentate nitrogen ligands and related copper(II) complexes as catalysts for stereoselective oxidation of catechols

摘要: Abstract Three new octadentate ligands, namely (R)-N,N′-dimethyl-N,N′-bis{3-[bis(1-methyl-2-imidazolylmethyl)]aminopropyl}-1,1′-binaphthyl-2,2′-diamine, (R)-DABN-3Im4, (R)-N,N′-dimethyl-N,N′-bis{4-[bis(1-methyl-2-benzimidazolylmethyl)]aminobutyl}-1,1′-binaphthyl-2,2′-diamine, (R)-DABN-4Bz4, and (S)-N2,N6-dimethyl-N2,N6-bis{2′-[bis(1-methyl-2-benzimidazolylmethyl)]aminomethyl}benzyl-2,6-diamino-1-exanol acetate, l -Lys-4Bz4, were employed for the synthesis of dinuclear trinuclear copper(II) complexes. The ligands contain two side arms different nature length which carry tridentate aminobis(benzimidazole) or aminobis(imidazole) residues as metal binding sites (A sites) connected to a central (R)-1,1′-binaphthyl-2,2′-diamine -lysine residue can bind third ion (B site). chiroptical properties complexes have been described. tested catalysts in oxidation 3,5-di-tert-butylcatechol, -, d -Dopa methyl esters by dioxygen give corresponding quinones. catalytic efficiency is moderate, but exhibit significant enantio-differentiating ability towards esters, albeit their lower. spacer (R)-DABN has much stronger recognition power than aliphatic -Lys In addition, highest stereoselectivity obtained with (R)-DABN-3Im4 complexes, containing carbon chains three atoms between groups donor units at A sites. all cases, preferred enantiomeric substrate configuration, dictated chirality residue.