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 OTf 2 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 2 e —3 c bonded diarylpropenyl and 4 e —3 c bonded bromine (Vi 2 Cu 4 Br 2 ) or 2 e —3 c bonded aryl (Vi 2 Cu 4 Ar 2 ) ligands positioned on opposite edges of a Cu 4 rectangle is proposed.