Synthesis and characterization of technetium-(IV) and -(III) complexes with bidentate Schiff bases. X-Ray molecular structure of chloro-(dimethylphenylphosphine)bis(N-phenylsalicylideneiminato)technetium(III)

Abstract

The complexes [TcCl₄(HL)₂] and [TcCl₃L(PPh₃)][HL =N-methylsalicylideneimine or N-phenylsalicylideneimine (Hpsal)] of the long-lived isotope technetium-99 were synthesized from [TcCl₄(PPh₃)₂], while the complexes [TcClL₂(PMe₂Ph)] were obtained through the reduction of the oxotechnetium(V) complexes [TcO(Cl)L₂] with PMe₂Ph. The crystal structure of the complex [TcCl(psal)₂(PMe₂Ph)] has been determined: a= 9.500(4), b= 10.596(4), c= 31.000(9)Å, β= 95.59(5)°, monoclinic, space group P2₁/c, and Z= 4. The co-ordination around Tc is approximately octahedral with the two chelate ligands mutually orthogonal, one ligand bridging two adjacent positions in the plane normal to the Tc–P bond and the other in the plane normal to the Tc–Cl bond. The phosphorus atom of PMe₂Ph is in a position trans to the aldimine nitrogen of one of the psal ligands, while the chlorine atom is trans to the nitrogen atom of the second psal, leaving the two phenolic oxygens in trans positions to each other.