Direct formation of new water soluble Re and Tc complexes containing PTA (1,3,5-triaza-7-phosphaadamantane) from their permetallated salts. Reactivity and X-ray crystal structures

A new one-pot synthetic procedure to new water-soluble rhenium and technetium complexes, directly from the corresponding permetallated species, is here presented. The new water-soluble M(IV) and M(III), (M = Re, Tc) paramagnetic complexes were obtained by treating [MO4]−with an excess of PTA (1,3,5-triaza-7-phosphaadamantane), in water. In the presence of SnCl2, the complexes [MCl3(PTA)3]Cl, (M = Re, 1; Tc, 3), were obtained in good yield, while in the absence of SnCl2the unexpected species containing methylated PTA, [MCl4(PTA-Me)2]Cl, (M = Re, 2; Tc, 4), were produced. A preliminary study of the reactivity of these products with N,N-diethyldithiocarbamate was also carried out: the diamagnetic binuclear μ-oxo species [M2O3(Et2NCS2)4] (M = Re, 6; Tc, 7) were isolated from the reactions of 1, 2 and 4 with dithiocarbamate. The reaction of 3 gave rise to an unusual epta-coordinated technetium(III) complex [Tc(Et2NCS2)3(PTA)] (5). The X-ray crystal structures of the new PTA complexes 2, 4, 5 and 7 have been determined.