Polarised single-crystal electronic absorption spectra of tetraphenylarsonium tetrahalogenonitridoruthenate(VI) compounds and the crystal and molecular structures of tetraphenylarsonium tetrabromonitrido-ruthenate(VI)

Abstract

The polarised single-crystal electronic absorption spectra of [AsPh₄][RuNX₄](X = Cl or Br) at room temperature and 5 K are reported in the range 10 000–40 000 cm^–1. The spectra have been interpreted using the observed polarisation data in conjunction with a parameterised ligand-field model. The single-crystal structure of [AsPh₄][RuNBr₄] has been determined by X-ray crystallography. The compound crystallises in the tetragonal space group P4/n, a=b= 12.691 (3), c= 8.035(3)Å, Z= 2. The [RuNBr₄]^– ion has 4mm(C_4v) symmetry with Ru–N 1.580(11), Ru–Br 2.453(1)Å, N–Ru–Br 104.25(3)°. The [AsPh₄]⁺ cation has crystallographic (S₄) symmetry, As–C 1.897(6)Å, C–As–C 104.64(40) and 111.95(21)°.