Novel triangulo Copper(I) Complexes Containing μ3-η1-Alkynyl, μ3-Chloride, and μ-η1-Isocyanide Ligands: X-ray Crystal Structure of [Cu3(μ3-η1-C⋮CC6H4CH3-4) (μ-η1-C⋮NC6H4CH3-4)(μ-dppm)3][BF4]2·3CH2Cl2

Abstract

Trinuclear copper(I) isocyanide complexes [Cu3(μ3-η1-C≡CR1)(μ-η1-C≡NR2)(μ-dppm)3][BF4]2 (dppm = bis(diphenylphosphino)methane; R1 = C6H5, R2 = CH2C6H5 (1), C6H11 (2), 4-CH3C6H4 (3); R1 = 4-CH3C6H4, R2 = CH2C6H5 (4), C6H11 (5), 4-CH3C6H4 (6)) have been prepared by reaction of the complexes [Cu3(μ3-η1-C⋮CR1)(μ-dppm)3][BF4]2 with isocyanides in CH2Cl2 at room temperature. Similarly, the treatment of the complex [Cu3(μ3-Cl)2(μ-dppm)3][BF4] with isocyanides in CH2Cl2 and in the presence of AgBF4 affords the complexes [Cu3(μ3-Cl)(μ-η1-C⋮NR)(μ-dppm)3][BF4]2 (R = CH2C6H5 (7), C6H11 (8), 4-CH3C6H4 (9)). Crystal structure of the complex 6 has been determined by X-ray diffraction methods. The cationic complex consists of a scalene triangle arrangement of the copper atoms bridged by three dppm ligands, with the p-tolyl isocyanide ligand bridging the shortest edge and the p-tolylethynyl ligand showing an asymmetric μ3-η1 bridging mode. The isocyanide group shows an unusual linearity (C−N−C = 171.13(9)°). 1H and 31P{1H...