Electron spin resonance studies of the oxidation of [TcVNCl2(EPh3)2](E = P or As) to [TcVINCl4]– by thionyl chloride: structure of dichloronitridobis(triphenylarsine)-technetium(V)

Abstract

The complexes [Tc^VNCl₂(EPh₃)₂](E = P or As) are oxidized to [Tc^VINCl₄]^– in thionyl chloride solution at room temperature. ESR spectroscopy has established the presence of technetium(VI) intermediates, [TcNCl₃(EPh₃)]: E = P, g_∥= 2.0316, g_⊥= 2.0026, A_∥= 0.0267 cm^–1, A_⊥= 0.0119 cm^–1, Q= 0.000 35 cm^–1, a_x=a_y= 0.0017 cm^–1, a_x= 0.00185 cm^–1; E = As, g_∥= 2.0246, g_⊥= 1.9986, A_∥= 0.0271 cm^–1, A_⊥= 0.0125 cm^–1, Q= 0.0003 cm^–1, a_x=a_y= 0.00195 cm^–1 and a_z= 0.0021 cm^–1. The crystal structure of [TcNCl₂(AsPh₃)₂]1 has been determined and is compared with those of Re^VN and Tc^VN phosphine complexes. Crystals of 1 are monoclinic, space group I2/a with a= 15.823(4), b= 9.638(2), c= 22.490(7)Å, β= 101.91 (2)° and Z= 4. Molecules of 1 possess C₂ symmetry with NTc–Cl and NTc–As angles of 110.51 (3) and 99.22(1)°, respectively. The TcN bond length is 1.601(5)Å.