Crystal and Molecular Structure of Triaqua-tri-μ-chloro-hexachloro-triangulo-trirhenium(III)-Bis[4,6-dimetylpyrimidine-2(1H)-thione hydrochloride]-Dihydrate

Abstract

Reaction between rhenium(III) chloride and 4,6-dimethylpyrimidine-2(1H)- thione hydrochloride in concentrated HCl solution results in the formation of [Re₃C1₉(H₂O)₃].2(C₆H₇N₂S.HCl).-2H₂O. The compound crystallizes in the orthorhombic space group Pnma with cell dimensions a 16.797(4), b 21.917(4), c 9.514(1) Å and Z 4. The structure was solved by the heavy-atom method and refined by least-squares calculations to a final R value of 0.0517 (R' 0.0602). The structure consists of discrete [Re₃Cl₉(H₂O)₃] units, protonated organic molecules, chloride ions, and water molecules. In the cluster three rhenium atoms are linked to form a triangle, with chlorine atoms bridging each pair of rheniums which present short Re-Re bonds [2.440(1), 2.433(1) and 2.444(1) Å]. Three water molecules in the equatorial plane and six chlorine atoms perpendicular to it (three above and three below) make the coordination around each rhenium distorted pentagonal bipyramidal.