Synthesis, crystal, molecular and electronic structure of rhenium nitrosyl with pyrazole in the coordination sphere

The reaction of [ReBr3(NO)(PPh3)2] complex with pyrazole (pzH) has been examined and a new rhenium nitrosyl - [ReBr3(NO)(PPh3)(pzH)] - has been obtained. The X-ray structure of the [ReBr3(NO)(PPh3)(pzH)] complex has been determined and its electronic structure has been calculated with the density functional theory (DFT) method with the use of B3LYP functional. Additional information about binding in the [ReBr3(NO)(PPh3)(pzH)] complex has been obtained by NBO analysis. The [ReBr3(NO)(PPh3)2] complex has also been investigated by IR and UV-Vis spectroscopy. The spin-allowed doublet-doublet electronic transitions of [ReBr3(NO)(PPh3)(pzH)] have been calculated with the time-dependent DFT method (TDDFT method) and the UV-Vis spectrum of the title complex has been discussed on this basis.