Synthesis and crystal structure of the salt of the protonated oxythiamine cation with a platinum(IV) mixed-halide anion [H2OT][Pt(Cl/Br)6

Abstract

The interaction of oxythiamine bromide hydrobromide with H2PtCl6 in a hydrochloric acid solution gives the salt of protonated oxythiamine (oxythiamine is the 4-methyl-3-[(2′-methyl-4′-oxo-3′,4′-dihydropyrimidinyl-5′)methyl]-5-(2-hydroxyethyl)thiazolium cation,C12H16N3O2S+) with a platinum(IV) mixed-ligand anion, (C12H17Br2.32Cl3.68N3O2PtS) (I). The crystals of salt I are monoclinic: a = 12.888(3), b = 10.835(2), c =15.898(4) A, β = 113.03(2)°, Z = 4, space group P21/c. They are built of the [H2OT]2+ cations and [Pt(Cl/Br)6]2− anions joined by hydrogen bonds and electrostatic and π-π stacking interactions. In the cation, the planar thiazolium and pyrimidine rings are bound through the methylene bridge, form a dihedral angle of 90.0°, and exist in the F conformation. The cations are combined into centrosymmetric cyclic dimers flanked on both sides by centrosymmetrically arranged octahedral anions to form short contacts.