Piperazine (and derivatives) platinum(II) complexes : Trans-bis(N-methylpiperazine-N,N')platinum(II) dichloride tetrahydrate

The title compound, trans-[L 2 Pt II ] 2+ .2Cl - .4H 2 O, (L = N-methylpiperazine), [Pt(C 5 H 12 N 2 ) 2 ]Cl 2 .4H 2 O, has been synthesized in the course of our work on complexes formed by the Pt 2+ ion with piperazine derivatives. X-ray diffraction analysis showed that two N-methylpiperazine molecules bind one Pt 2+ ion in such a way that the two methyl groups lie in opposite directions with respect to the Pt atom. The coordination around the Pt atom is square planar with four N atoms occupying the coordination sites, and the coordination plane is perfectly planar because the Pt atom lies on a centre of symmetry. This type of coordination imposes a boat conformation on the six-membered N-methylpiperazine ring. As found in other N-methylpiperazine complexes, the molecule has a local mirror plane coincident with the square-planar coordination plane and nearly bisecting the piperazine six-membered ring.