The First Copper(I)-Olefin Complexes Bearing a 1,3,4-Oxadiazole Core : Alternating-Current Electrochemical Crystallization, X-ray Experiment and DFT Study

Abstract

By means of alternating-current electrochemical technique, four new π-complexes, namely [Cu2(C11H10N2OS)2Br1.91Cl0.09] (1), [Cu(C11H10N2OS)NO3] (2), [Cu2(C11H10N2OS)2(H2O)2](BF4)2 (3) and [Cu2(C11H10N2OS)2(H2O)2](ClO4)2 (4), were obtained using copper(II) salts and the 2-(allylthio)-5-phenyl-1,3,4-oxadiazole (C11H10N2OS) ligand. The metal and halogen centers in 1 form Cu2X2 dimers; the N-atom from the oxadiazole ring and the Cdouble bond; length as m-dashC bond of the allyl group from the same ligand complete the copper coordination environment, giving [Cu(C11H10N2OS)X]2 isolated fragments. The ligand plays the same chelating role in 2, whereas the O (NO3) atom occupies the third position in the copper atom’s equatorial plane. Two more elongated Cu–O(NO3) contacts associate the Cu(C11H10N2OS)NO3 fragments into 1D chains. The geometries of the [Cu(C11H10N2OS)]22+ cationic units in 3 and 4 are affected by the position of two water molecules in the coordination spheres of the copper atoms with respect to the plane containing the oxadiazole rings and the copper atoms. The molecular structures and Raman spectra of the compounds were computed using the DFT/B3LYP/cc-pVDZ level of theory. The results are compared with the experimental data obtained and used for vibrational band assignment.