Tri- and Tetravalent Titanium Alkyls Supported by Organic Amides

The reactions of both trivalent [(Cy 2 N) 2 Ti(μ-Cl) 2 Li(TMEDA)] ( 1 ) and tetravalent [(Cy 2 N) 2 TiCl 2 ] ( 5 ) with R‘Li in THF or diethyl ether gave Ti(IV) complexes (Cy 2 N) 2 TiR‘ 2 [R‘ = CH 2 CMe 3 ( 7 ), CH 2 CMe 2 Ph ( 8 ), CH 2 SiMe 3 ( 9 )]. Conversely, the reactions of 1, [{( i -Pr) 2 N} 2 TiCl 2 ][Li(TMEDA) 2 ] ( 2 ), and [{(Me 3 Si) 2 N} 2 TiCl 2 ][Li(TMEDA) 2 ] ( 3 ) with R‘Li [R‘ = Me, Ph, CH 2 Ph] gave the corresponding trivalent derivatives [(Cy 2 N) 2 Ti(μ-Bz) 2 Li(TMEDA)] ( 4a ), [(Cy 2 N) 2 Ti(μ-Me) 2 Li(TMEDA)] ( 4b ), [{( i -Pr) 2 N} 2 TiPh 2 ][Li(TMEDA) 2 ] ( 11 ), and [{(Me 3 Si) 2 N} 2 Ti(CH 2 Ph) 2 ][Li(TMEDA) 2 ] ( 12 ) via simple ligand replacement reactions. Oxidation of 12 with diphenylfulvene gave {(Me 3 Si) 2 N} 2 Ti(CH 2 Ph) 2 ( 13 ). All these compounds are thermally labile and yielded intractable materials upon thermolysis. Only in the case of the neophyl derivative (Cy 2 N) 2 Ti(CH 2 CMe 2 C 6 H 5 ) 2 ( 8 ) a cyclometalated compound (Cy 2 N) 2 Ti(CH 2 CMe 2 C 6 H 4 ) ( 10 ) was isolated and crystallized from the thermolyzed solution. The reaction of 1 with styrene oxide provided the Ti−oxo complex [(Cy 2 N) 2 TiCl] 2 O ( 14 ) which gave, upon alkylation with MeLi, the corresponding dinuclear alkyl derivatives [(Cy 2 N) 2 TiMe] 2 O ( 15 ). The molecular structures of 1 and 10−14 were demonstrated by X-ray diffraction analysis.