Preparation of the technetium(VI) aquanitrido complexes (NEt 4)[TcNX 4(OH 2)] (X= Cl or Br). Crystal structures of (NEt 4)[TcNBr 4(OH 2)] and Cs 2[TcNCl 5

Abstract

Addition of NEt 4X to a conc. HX solution of [TcNX 4(OH 2)] − (X= Cl or Br) yields crystals of (NEt 4)[TcNX 4(OH 2)] (X=Cl ( 1) or Br ( 2)). Complex 2 crystallises in the orthorhombic space group Pnma with a = 11.366(1), b = 12.930(2), c = 11.540(1) Å and Z = 4. Refinement with 1434 data measured with Cu K α radiation converged with R = 0.047. The complex anion has distorted octahedral geometry with a water molecule trans to the nitrido ligand (TcN 1.599(9) and TcOH 2 2.443(7) Å). Crystals of Cs 2[TcNCl 5] ( 3) belong to the cubic space group Fm 3 m with a = 10.211(1) Å and Z = 4. The ligands of the complex anion are statistically disordered over six octahedral sites as required by the cubic space group. Refinement based on 78 data measured with Cu Kα radiation, and with a fixed TcN distance of 1.6 Å, converged with R = 0.034. In this model Tc is displaced 0.401(3) Å from the plane of the cis ligands towards the nitrido ligand with TcCl cis = 2.373(5), TcCl tras = 2.740(5) Å.