Binuclear half-sandwich cobalt(iii) and rhodium(iii) ortho-carboranedichalocogenolato complexes with ether chain-bridged bis(cyclopentadienyl) ligand

Abstract

1, 1′-(3-Oxapentamethylene)dicyclopentadiene [O(CH₂CH₂C₅H₅)₂] (1), containing a flexible chain-bridged group, was synthesized by the reaction of sodium cyclopentadienide with bis(2-chloroethyl) ether through a slightly modified literature procedure. Furthermore, the binuclear cobalt(III) complex O[CH₂CH₂(η⁵-C₅H₄)Co(CO)I₂]₂ (3) and insoluble polynuclear rhodium(III) complex {O[CH₂CH₂(η⁵-C₅H₄)RhI₂]₂}_n (8) were obtained from reactions of 1 with the corresponding metal fragments and they react easily with PPh₃ to give binuclear metal complexes, O[CH₂CH₂(η⁵-C₅H₄)Co(PPh₃)I₂]₂ (4) and O[CH₂CH₂(η⁵-C₅H₄)Rh(PPh₃)I₂]₂ (9), respectively. Complexes 3, 4 and 9 react with bidentate dilithium dichalcogenolato ortho-carborane to give eight binuclear half-sandwich ortho-carboranedichalcogenolato cobalt(III) and rhodium(III) complexes O[CH₂CH₂(η⁵-C₅H₄)Co(PPh₃)(E₂C₂B₁₀H₁₀)]₂ (E = S (5a) and Se (5b)), O[CH₂CH₂(η⁵-C₅H₄)]₂Co₂(E₂C₂B₁₀H₁₀) (E = S (6a) and Se (6b)), O[CH₂CH₂(η⁵-C₅H₄)Co(E₂C₂B₁₀H₁₀)]₂ (E = S (7a) and Se (7b)) and O[CH₂CH₂(η⁵-C₅H₄)Rh(PPh₃)(E₂C₂B₁₀H₁₀)]₂ (E = S (10a) and Se (10b)). All complexes have been characterized by elemental analyses, NMR spectra (¹H, ¹³C, ³¹P and ¹¹B NMR) and IR spectroscopy. The molecular structures of 3, 5a, 6a, 6b, 9 and 10b were determined by X-ray diffractometry.