GROUP-IB ORGANOMETALLIC CHEMISTRY .31. SYNTHESIS AND CHARACTERIZATION OF TETRANUCLEAR ME2N-SUBSTITUTED AND ME2NCH2-SUBSTITUTED DIARYLPROPENYLCOPPER-COPPER ANION COMPOUNDS (VI2CU4X2) CONTAINING BRIDGING PROPENYL LIGANDS - ISOLATION OF A THERMALLY STABLE MIXED DIARYLPROPENYL-ARYLCOPPER COMPOUND (VI2CU4AR2)

Thermally stable 1,2-diarylpropenylcopper compounds (ViCu2X)n (Vi = (2-Me2NC6H4)CC(Me)(C6H4Me-4), X = Br (n = 2) or OTf2 2 OTf = trifluoromethanesulphonate = triflate. and Vi = (2-Me2NCH2C6H4)CC(Me)(C6H4Me-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 Vi2Cu4Br2 (Vi = (2-Me2NC6H4) CC(Me)- (C6H4Me-4)) with RLi (R = 4-MeC6H4CC or 4-MeOC6H4CC) mixed alkenyl/ alkynylcopper compounds (ViCu2R)n were obtained. Reaction of Vi2Cu4Br2 with 2-dimethylaminophenyllithium (ArLi) yielded Vi2Cu4Ar2, the first representative of the class of mixed alkenyl/arylcopper compounds. This compound was also prepared via reaction of Ar4Cu6Br2 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 (Vi2Cu4Br2) or 2e-3c bonded aryl (Vi2Cu4Ar2) ligands positioned on opposite edges of a Cu4 rectangle is proposed. © 1979.