Nitrosyl complexes of rhenium. Part 3. Crystal and molecular structure of tetraethylammonium tetrachioronitrosyl(pyridine)rhenate-(1–)

Abstract

The crystal and molecular structure of the title compound has been established by Patterson and Fourier methods based on three-dimensional X-ray counter data. The salt gives monoclinic crystals, space group C2/c, with unit-cell constants a= 22.28(2), b= 10.67(1), c= 16.98(2)Å, β= 94.15(8)°, and Z= 8. The structure has been refined by least-squares methods to R 0.030 for 2 697 independent reflections. The anion [ReCl₄(NO)(py)]^–shows a distorted-octahedral geometry, with the four chlorine atoms lying in an equatorial plane and the other two ligands in axial directions. The Re–Cl bond lengths are in the range 2.353–2.379(2)Å. The nitrosyl group is linked linearly to the rhenium atom, as [NO]⁺, with Re–N and N–O bonds of 1.749(6) and 1.171 (9)Å. The Re–N(pyridine) bond distance [2.218(6)Å] is rather long, probably because of steric interactions involving the chlorine atoms and the ortho-hydrogen atoms of the pyridine.