UV–Vis Identification and DFT-Assisted Prediction of Structures of Cu(II)–Alkyl Chlorocomplexes

Abstract

The structures of paramagnetic copper complexes, the products of photolysis of tetrachlorocuprates of quaternary ammonium in frozen solvents, earlier denoted as 1-Cu and 2-Cu, were established on the basis of comparison of experimental and theoretical UV-vis spectra. UV-vis spectra of photolysis products were registered at 77-116 K. Comparison with the EPR data in this temperature range allowed to assign photolysis products bands in the vis spectrum either to 1-Cu or to 2-Cu. Model structures for 1-Cu and 2-Cu were proposed. TD-DFT calculated spectra of model compounds along with CuCl(4)(2-) anion are in excellent agreement with the experiment. The comparison of UV-vis and EPR data and results of TD-DFT calculations evidence that 1-Cu and 2-Cu are paramagnetic organochlorocuprates(II) with general formulas Cu(II)Cl(2)R and Cu(II)Cl(3)R, respectively, where R is (-C(6)H(12))N(+)(C(6)H(13))(3).