Synthesis and structure of trinuclear methoxy-bridged titanium(III)-magnesium complexes: [(C(5)H(5-n)Me(n))(2)Ti(mu-OMe)(2)](2)Mg (n=4 and 5)

The hydride complexes [(C(5)Me(5))(2)Ti(mu-H)(2)]Mg-2 (1) and [(C(5)HMe(4))(2)Ti(mu-H)(2)]Mg-2 (2) smoothly react with four equivalents of methanol to give the methoxy complexes [(C(5)Me(5))(2)Ti(mu-OMe)(2)]Mg-2 (3) and [(C(5)HMe(4))(2)Ti(mu-OMe)(2)]Mg-2 (4), The X-ray crystal analysis of 4 revealed a nearly linear arrangement of the metal atoms in an unsymmetrical molecule, The EPR spectra of the frozen toluene glass of 3 and 4 showed the triplet state spectra with very similar zero field splitting of rhombic symmetry. The distance between the unpaired electrons in 4 was estimated from the value of D = 0.00958 cm(-1) to be 6.43 Angstrom, in good agreement with the crystallographic Ti-III-Ti-III distance of 6.329(1) Angstrom. Complex 4 reacts with excess dibutyl magnesium to give a mixture of 2 and [(C(5)HMe(4))(2)Ti(mu-H])(2)Mg(mu-OMe)](2) (6). A mixture of 4 and methylalumoxane (1:100) did not induce the polymerization of ethylene.