Synthesis of technetium complexes with a P,N bidentate phosphine amine ligand. Crystal structure of bis[(o-amidophenyl)diphenylphosphine-κN,P][(o-aminophenyl)diphenylphosphine-κN,P]technetium(III) perchlorate

Abstract

The reactions of (o-aminophenyl)diphenylphosphine (HL) with ammonium pertechnetate have been investigated. The complexes [TcL₃]1 and [TcL₂(HL)]⁺2, with [TcO₄]^–, [ClO₄]^– and [CF₃CO₂]^– as counter anions, were isolated from the reaction mixture depending on the pH. The transformation of 1 into 2, and vice versa, was identified as an acid–base equilibrium by UV/VIS spectrophotometric measurements. The products have been characterized by means of the usual physicochemical determinations. Compound 2, as its perchlorate salt, has been studied by means of X-ray analysis. It exhibits a distorted-octahedral configuration in a monoclinic crystal system: space group P2₁/n, a= 11.009(2), b= 19.361(3), c= 24.473(3)Å, β= 100.76(1)° and Z= 4. The structure was solved by patterson and Fourier methods and refined by least-squares methods to R= 0.052 using 5096 observed reflections. Relevant bond lengths and angles are: Tc–P(1) 2.483(2), Tc–P(2) 2.430(2), Tc–P(3) 2.436(2), Tc–N(1) 2.048(5), Tc–N(2) 1.948(5), Tc–N(3) 1.979(5)Å; P(2)–Tc–P(3) 160.2(1), P(1)–Tc–N(3) 164.3(2), N(1)–Tc–N(2) 163.6(2)°.