A Monoclinic Form of Tetrakis(1-methylimidazole-N³)platinum(II) Diperchlorate

The monoclinic polymorph of the title compound, [Pt(C₄H₆N₂)₄](ClO₄)₂, is reported. The two main differences between this form and the triclinic form reported previously lie in the conformation of the [Pt(C₄H₆N₂)₄]²⁺ cation and in the crystal packing. In both forms, the cation lies on an inversion center, but the orientations of the 1-methylimidazole (MeIm) ligands are different. In the present study, two trans-MeIm ligands are oriented perpendicular to the Pt-coordination plane, while the other two are approximately coplanar with this plane. This is the first reported instance of coplanarity in an N-alkylimidazole–platinum(II) complex. The packing of the molecular cations in the monoclinic form involves no π-stacking, in contrast with the packing observed in the triclinic form.

-1