Comparative Analysis of Crystal Structures between 2,2′-Bipyridine and 6,6′-Dimethyl-2,2′-Bipyridine Supported CuSCF3 Complexes: An Unusual Coordination Transition from Mononuclear to Binuclear Mode

Abstract

We report herein the synthesis of CuSCF3 complex supported by 6,6′-dimethyl-2,2′-bipyridine via the strategy of triphenylphosphine-mediated deoxygenation of CF3SO2Na in the presence of cuprous chloride. The molecular structure of this new cuprous complex was characterized by elemental analysis, 1H (13C, 19F) NMR spectra and verified by X-ray crystallography. Unlike the classical [(2,2′- bipyridine)Cu(SCF3)] complex, 6,6′-dimethyl-2,2′-bipyridine supported cuprous trifluoromethylthiolate complex was dimerized in the form of [{(6,6′-dimethyl-2,2′-bipyridine)Cu(SCF3)}2]. The X-ray crystal structure revealed the Cu2S2 cyclic pattern and sulfur atoms serving as the bridge. The Cu-Cu distance was equal to 3.083 Å which was remarkably longer than the analogous [{(1,10-phenanthroline)Cu(SCF3)}2] (2.5781(9) Å). This interesting phenomenon demonstrated that the substituents on the ligand scaffolds have profound influence on the coordination modes of these N,N-ligand coordinated CuSCF3 complexes.