Preparation and characterization of dirhenium complex anions of the type [Re 2Cl 7(dithioether)] − with ReRe quadruple bonds

Abstract

Two dirhenate(III) anions containing dithioether ligands and ReRe quadruple bonds have been synthesized and characterized by X-ray crystallography. Under mild reaction conditions, both 3,6-dithiaoctane (Ch 3CH 2SCH 2CH 2SCH 2CH 3 or dto) and 2,5-dithiahexane (CH 3SCH 2CH 2SCH 3 or dth) displace a single chloride ligand from [Re 2Cl 8] 2− to yield [Re 2Cl 7(dto)] − and [Re 2Cl 7(dth)] −, respectively. The tetra-n-butylammonium (Bu 4N) salts of these complex ions have been isolated and found to react with additional dithioether to produce the unsymmetrical compounds Re 2Cl 5(dto) 2 and Re 2Cl 5(dth) 2 with ReRe triple bonds. The complex (Bu 4N[Re 2Cl 7(dto)] crystallizes in the triclinic space group P 1 ̄ with a = 11299(3), b = 11.552(4), c = 14.654(4)Å, a = 108.19(2), β = 104.07(2), γ = 88.65(3)° and Z = 2, while (Bu 4N)[Re 2Cl 7(dth)] crystalline in the monoclinic space group P2 1 with a = 10.361(2), b = 15.567(4), c = 11.663(3) A ̊ , β = 117.01(2)° and Z = 2. The ReRe bond distances are 2.248(1) and 2.257(1) Å for the dto and dth complexes, respectively.