Syntheses and structural characterization of vanadium and aluminum thiolates

Stoichiometric reaction of [VCl(DIPP)(2)(THF)(2)] (DIPP = 2,6-diisopropylphenoxide) with 2,2'-oxydiethanethiol O(CH2CH2SH)(2) in CH3CN yields two products. [V-IV{O(CH2CH2S)(2)}(2)], 1, and [V-II(CH3CN)(6)][(VCl2)-Cl-III{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)(mu -DIPP)(4)Li-2(THF)(4)], 3, [V-III(mu -DIPP)(2){O(CH2CH2S)(2)}Li-4(THF)(2)], 4, [V-II(PyT)(2)(TMEN)], 5, and [V-III(mu -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 [V-2(mu -O)( (THF)(6)], 7, and the organoaluminum compound [Al-2{mu,eta (3)-(OCH2CH2SCH2CH2S)}(2)(CH3)(2)], 8. The crystal structure of 8 showed it to he 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).