Novel rhenium(III) complexes with the picolinate ligand: Synthesis, spectroscopic investigations, X-ray structures and DFT calculations for [ReX2(pic)(PPh3)(2)] complexes

摘要

The paper presents a combined experimental and computational study of novel rhenium(III) complexes with the picolinate ligand - [ReCl2(pic)(PPh3)(2)] (1) and [ReBr2(pic)(PPh3)(2)] (2). Both complexes 1 and 2 have been characterised spectroscopically and structurally (by single-crystal X-ray diffraction). Complex 1 has been additionally studied by magnetic measurement. The magnetic behavior is characteristic of a mononuclear d(4) low-spin octahedral Re(III) complex (T-3(1g) ground state) and arises because of the large spin-orbit coupling (zeta = 2500 cm(-1)), which gives a diamagnetic ground state. DFT and time-dependent (TD)DFT calculations have been carried out for complex 1, and UV-vis spectra of the [ReX2(pic)(PPh3)(2)] compounds have been discussed on this basis.