Syntheses and Structural Characterization of Vanadium and Aluminum Thiolates

Abstract

Stoichiometric reaction of [VCl(DIPP)2(THF)2] (DIPP = 2,6-diisopropylphenoxide) with 2,2‘-oxydiethanethiol O(CH2CH2SH)2 in CH3CN yields two products: [VIV{O(CH2CH2S)2}2], 1, and [VII(CH3CN)6][VIIICl2{O(CH2CH2S)2}]2, 2. Compounds 1 and 2 were identified by conventional methods, including single-crystal X-ray diffraction for 2. Compound 2 reacts with Li(DIPP) and Na(PyT) (PyT = pyridine-2-thiolate) in the presence of TMEN (TMEN = N,N,N‘,N‘‘-tetramethylethylenediamine) to give [VII(μ-DIPP)4Li2(THF)4], 3, [VIII(μ-DIPP)2{O(CH2CH2S)2}Li4(THF)2], 4, [VII(PyT)2(TMEN)], 5, and [VIII(μ-PyT)2{O(CH2CH2S)2}Na(THF)2], 6. When combined with an aluminum activator and MgCl2, compound 2 forms an active catalyst for ethylene polymerization. The interaction of 2 with an excess of Al(CH3)3 causes {O(CH2CH2S)2}2- ligand abstraction from the vanadium center to give [V2(μ-O)Cl4(THF)6], 7, and the organoaluminum compound [Al2{μ,η3-(OCH2CH2SCH2CH2S)}2(CH3)2], 8. The crystal structure of 8 showed it to be a dimer with aluminum atoms bridged by two alkoxo oxygen atoms from the ligand {OCH2CH2SCH2CH2S}2-, formed by transformation of the starting {O(CH2CH2S)2}2- ligand under the influence of Al(CH3)3.