Synthesis, crystal, molecular and electronic structure of the [ReCl4(pzH)(PPh3)] and [ReCl4(pyz)(PPh3)] complexes

The reactions of the [ReCl4(PPh3)2] complex with pyrazole (pzH) and pyrazine (pyz) have been examined and two novel Re(IV) compounds – [ReCl4(pzH)(PPh3)] (1) and [ReCl4(pyz)(PPh3)] (2) – have been obtained. The compounds have been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The electronic structures of 1 and 2 have been calculated with the density functional theory (DFT) method. The spin-allowed quartet–quartet electronic transitions of 1 and 2 have been calculated with the time-dependent DFT method, and the UV–Vis spectra of the title compounds have been discussed on this basis. From magnetic studies a small, negative value of J obtained confirms the occurrence of weak antiferromagnetic interactions between the rhenium centers in the crystal lattice.

Graphical abstractThe reactions of the [ReCl4(PPh3)2] complex with pyrazole (pzH) and pyrazine (pyz) have been examined and two novel Re(IV) compounds – [ReCl4(pzH)(PPh3)] (1) and [ReCl4(pyz)(PPh3)] (2) – have been obtained. The compounds have been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The electronic structures of 1 and 2 have been calculated with the density functional theory (DFT) method. The spin-allowed quartet–quartet electronic transitions of 1 and 2 have been calculated with the time-dependent DFT method, and the UV–Vis spectra of the title compounds have been discussed on this basis. From magnetic studies a small, negative value of J obtained confirms the occurrence of weak antiferromagnetic interactions between the rhenium centers in the crystal lattice.Figure optionsDownload full-size imageDownload as PowerPoint slide