DFT calculation and X-ray structure of the [ReCl3(pzH)3] complex

The [ReCl3(pzH)3] · H2O · HCl complex has been obtained in the reaction of [ReOCl3(PPh3)2] with an excess of pzH in wet benzene under argon atmosphere. The well-known capacity of PPh3 to interact with the ReO bond in rhenium(V) oxo-complexes explains the course of the reaction. The rhenium atom of [ReCl3(pzH)3] is in a distorted octahedral environment and the two groups of ligands (halide ions and pyrazole molecules) are arranged in a meridional fashion. The geometric parameters of [ReCl3(pzH)3] have been examined using the density functional theory (DFT) method. The UV-Vis spectrum of [ReCl3(pzH)3] has been discussed on the basis of the electronic transitions calculated with the time-dependent DFT method (TDDFT).