Hexachlororhenate(IV) salts of ruthenium(III) cations: X-ray structure and magnetic properties

Two novel rhenium(IV)–ruthenium(III) compounds of formulae [RuCl(NH3)5]2[ReCl6]Cl2 (1) and [RuCl2(en)2]2[ReCl6]·2CH3CN (2) (en = 1,2-ethylenediamine) have been prepared and characterized. Their crystal structures were determined by single-crystal X-ray diffraction. 1 crystallizes in the monoclinic system with C2/m as space group, whereas 2 crystallizes in the triclinic system with space group P(−1). The crystal structures of 1 and 2 are made up of discrete [ReCl6]2− anions and [RuCl(NH3)5]2+ (1) or [RuCl2(en)2]+ (2) cations held together by N–H···Cl hydrogen bonds, van der Waals and electrostatic forces. The magnetic properties were investigated from susceptibility measurements performed on polycrystalline samples of 1 and 2 in the temperature range 1.9–300 K. In both compounds, the variation of χMT in the high-temperature range reveals an antiferromagnetic coupling whereas they exhibit behaviour typical of spin-canted systems with magnetic ordering below ca. 11.0 (1) and ca. 4.5 K (2).