Novel results on thiodiacetate zinc(II) complexes: Synthesis and structure of [Zn(tda)(phen)]2 · 5H2O

Novel zinc thiodiacetate complex [Zn(tda)(H2O)]n (1) image was obtained from the reaction of aqueous solutions of zinc dichloride with a 1:1 mixture of Na2CO3 and thiodiacetic acid. Complex 1 is a different hydrate compound with respect to the known species [Zn(tda)(H2O)3] · H2O. The selective formation of 1 or [Zn(tda)(H2O)3] · H2O can be achieved by controlling the crystallization conditions and it is even possible to interconvert the two hydrate compounds by fast or slow crystallization processes. The reaction of 1 with o-phenanthroline (phen) gave the dinuclear compound [Zn(tda)(phen)]2 · 5H2O (2), which was identified by X-ray analysis. The water crystallization molecules are interconnected by hydrogen bonds and they are aligned inside channels, which are parallel to the c-axis.