Structural studies of nitrido-complexes: X-ray crystal structure of tetraphenylarsonium pentakis(isothiocyanato)nitridorhenate(VI)

Abstract

The crystal structure of the title complex [AsPh₄]₂[ReN(NCS)₅] has been determined from single-crystal X-ray data. The crystals are monoclinic, with unit-cell dimensions a= 12330(1), b= 18.600(1), c= 13.385(1)Å, β= 118.74(1), space group Pc, and Z= 2. Least-squares. refinement has reached R 0.029 for 4 074 independent reflections. The structure consists of tetrahedral tetraphenylarsonium cations, and octahedral [ReN(NCS)₅]^2– anions which contain a terminal nitride ligand and NCS groups bonded through the nitrogen atoms. Approximate 4mm(C_4v) point symmetry is found for the anion, with the rhenium atom displaced 0.21 Å out of the plane of four equatorial nitrogens and N (nitride)-Re–N (isothiocyanate) angles of ca. 96 °. The triply bonded Re–N (nitride) distance is 1.657 Å. The mean Re–N(equatorial) bond length is 2.021 Å, while the Re–N(axial) bond trans to the nitride ligand is appreciably longer at 2.307 Å. In the tetraphenylarsonium cations the mean As–C bond length is 1.910 Å.