Synthesis, structural determination, and ethylene polymerization chemistry of mono(salicylaldiminato) complexes of titanium(IV)

Abstract

Titanium(IV)mono(salicylaldiminato) complexes [L 1 Ti(NMe2)3 ]( 1) and [L 1 TiCl3 ]( 2 )h ave been synthesized by treatment of Ti(NMe2)4 or TiCl4 with one equivalent of [4; 6-Bu t -2-(CHNBu t )C 6 H 3 OH] (L 1 H )o r[4; 6-Bu t -2-(CHNBu t )C 6 H 3 OSiMe 3 ] (L 1 SiMe3), respectively. The compounds are monomeric in solution and in the solid-state. Reactions of TiCl4 with one equivalent of [4; 6-Bu t -2-(CHNCH2Ph)C6H3OH] (L 2 H) and [4; 6-Bu t -2-fCHN(2-C6H4OH)gC6H3OH] (L 3 H2) produced [L 2 TiCl2(m-Cl)]2 (3) and [L 3 TiCl2]2 (4), respectively. [L 3 TiCl2(THF)] (5) was also produced in quantitative yield when 4 was stirred in THF for 16 h. The reaction of TiCl4 with L 3 H2 (Two equivalents) in toluene gave [(L 3 )2Ti] (6). The molecular structures of 2/4 and 6 were established by single-crystal X-ray diffraction studies; and 4 displayed a rare face to face p/p stacking interaction in its structure. Compounds 1 and 2 showed modest ethylene polymerization activities at 25 8C with 900 molar equivalents of methylalumoxane (MAO) as cocatalyst.