Synthesis and structural characterization of copper(II) bishexafluoroacetylacetonate complexes with N-donor ligands

Abstract

The reactions of Cu(hfac) 2 with different N-donor ligands such as 2-ethynylpyridine and imidazole give copper complexes Cu(hfac) 2(ethynylpyridine) ( 1) and Cu(hfac) 2(ImH) 2 ( 2), respectively. The reaction of Cu(hfac) 2 · (ethynylpyridine) ( 1) and ethynylpyridine with oxygen in tmeda (tmeda = N, N, N′, N′-tetramethylethylenediamine) in the presence of copper(I) chloride gives Cu(hfac) 2(tmeda) ( 3). Finally, [Cu(hfac) 2(H 2O)] 2(μ-TCNE) ( 4) was prepared by reaction of Cu 2O on the free acid β-diketone in the presence of TCNE (TCNE = tetracyanoethylene) (ratio 1.5:1:1), under an atmosphere of oxygen-free Ar. The previously synthesized Cu(hfac)TCNE proceeded further reaction by disproportionation, yielding [Cu(hfac) 2(H 2O)] 2(μ-TCNE). All new compounds have been structurally characterized and their thermal properties were examined by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC).