Synthesis and Structure of Di(1,2,4,6-tetraphenylpyridinium) Octachlorodirhenate(III)

The (NC₅H₂(C₆H₅)₄)₂Re₂Cl₈] · 2CH₃CN compound was prepared by the reaction of (n-Bu₄N)₂Re₂Cl₈] with the 1,2,4,6-tetraphenylpyridinium tosylate in the acetonitrile; it crystallizes upon cooling of the solution at –15°C. The structure consists of the ((C₆H₅)₄C₅H₂N)⁺ cation and Re₂Cl ₈ ^2? anion with virtual D_4h symmetry. The average Re–Re and Re–Cl bond distances are 2.2205 and 2.3431 Å, respectively. In the structure, the Re₂Cl ₈ ^2? anions are disordered, such that 71.34% of the Re–Re units are aligned in one direction while 28.66% are aligned orthogonal to it. The principal crystallographic data are as follows: sp. gr. R?3; a = 26.554(1) Å, c = 23.666(1) Å; V = 14451.6(1) ų; Z = 9; D_x = 1.643 g cm^–3.