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

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 P2(1)/n, a = 11.009(2), b = 19.361 (3), c = 24.473(3) angstrom, beta = 100.76(1)-degrees 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) angstrom; P(2)-Tc-P(3) 160.2(1), P(1)-Tc-N(3) 164.3(2), N(1)-Tc-N(2) 163.6(2)-degrees.