Crystal structure, thermal analysis and spectroscopic properties of Tetrabutylammonium 3,5-bis(dicyanomethylene)-cyclopentane-1,2,4-trionate: An intriguing pseudo-oxocarbon and its zinc(II) complex

Abstract

The synthesis, thermal behavior, spectroscopic properties and crystal structure of tetrabutylammonium Croconate Violet, (NBu 4) 2CV, are described. This compound crystallizes in the triclinic space group P 1 ¯ with a=12.440(1), b=19.003(2), c=19.679(2) Å; α=72.809(4), β=77.037(4), γ=84.702(6)° and Z=4. Additionally, from the reaction between (NBu 4) 2CV and ZnCl 2, the first Zn(II) complex containing the CV 2− dianion, (NBu 4) 4[Zn(CV) 3] was obtained. The complex was characterized by infrared and Raman spectroscopic techniques as well as by 1H and 13C NMR analysis. These data show that the coordination of pseudo-oxocarbon to the metal center occurs through the vicinal oxygen atoms in a chelating fashion while the nitrile groups are not involved in the formation of the complex.