Structural studies of Technetium Complexes. VIII. The Crystal Structure of Tetraphenylarsonium Tetrabromonitridotechnetate(VI)

Abstract

The crystal structure of [AsPh₄] [TcNBr₄] has been determined by single- crystal X-ray diffraction methods at 20±1°C. Crystals are tetragonal, space group P4/n, with a 12.875(2), c 7.992(1)Ǻ, and Z 2. Full-matrix least-squares refinement gave a final R value of 0.039 for 1263 independent reflections. The compound is isostructural with the series [AsPh₄] [MNBr₄] (M = Mo, Ru , Re or Os) and [AsPh⁴] [MNCl₄](M = Mo, Tc , Ru, Re or Os), and with [AsPh₄] [OsNI₄] and [AsPh₄]- [MOCl₄](M = Mo or Re). The [TcNBr₄]^- anion in [AsPh₄] [TcNBr₄] possesses C_4v symmetry with Br- Tc -Br bond angles of 87.08(1) and 153.91(4)°, and N= Tc -Br bond angles of 103.04(2)°. The Tc≡N bond distance is 1.596(6)Ǻ, and the Tc - Br distances are 2.4816(5)Ǻ.