Group IB Organometallic Chemistry XXXI. Synthesis and characterization of tetranuclear Me2N- and Me2NCH2-substituted diarylpropenylcopper-copper anion compounds (Vi2Cu4X2) containing bridging propenyl ligands. Isolation of a thermally stable mixed diarylpropenyl/arylcopper compound (Vi2Cu4Ar2)

Abstract

Thermally stable 1, 2-diarylpropenylcopper compounds (ViCu{2}X){n} (Vi = (2-Me{2}NC{6}H{4})C@?C(Me)(C{6}H{4}Me-4), X = Br (n = 2) or OTf2OTf = trifluoromethanesulphonate = triflate. and Vi = (2-Me{2}NCH{2}C{6}H{4})C@?C(Me)(C{6}H{4}Me-4), X = Br (n = 2)) have been prepared by reaction of configurationally pure E-ViLi compounds with copper(I) salts. Via ligand substitution reactions of Vi{2}Cu{4}Br{2} (Vi = (2-Me{2}NC{6}H{4}) C@?C(Me)- (C{6}H{4}Me-4)) with RLi (R = 4-MeC{6}H{4}C@?C or 4-MeOC{6}H{4}C@?C) mixed alkenyl/ alkynylcopper compounds (ViCu{2}R){n} were obtained. Reaction of Vi{2}Cu{4}Br{2} with 2-dimethylaminophenyllithium (ArLi) yielded Vi{2}Cu{4}Ar{2}, the first representative of the class of mixed alkenyl/arylcopper compounds. This compound was also prepared via reaction of Ar{4}Cu{6}Br{2} with ViLi. Based on molecular weight data and dynamic NMR spectral evidence a tetranuclear structure with 2e-3c bonded diarylpropenyl and 4e-3c bonded bromine (Vi{2}Cu{4}Br{2}) or 2e-3c bonded aryl (Vi{2}Cu{4}Ar{2}) ligands positioned on opposite edges of a Cu{4} rectangle is proposed.