Dichlorotitanium complex

The selective S3mthesis of tri- and dichlorotitanium complexes 140-142 bearing chiral tridentate Schiff base ligands derived from (lf ,25)-( )-l-aminoindanol (Fig. 20) has been recently reported. X-ray structural studies of these complexes revealed a mononuclear feature with an octahedral coordination sphere at the metal center, and a meridional occupation of the Schiff base. Surprisingly, though these complexes lack the typical ROP-initiating units such as aUcoxides or amides, they are effective catalysts for the controlled ROP of L-lactide, as evidenced by the linearity of the molecular weight versus [l-LA] [Ti] ratio as well as the narrow PDIs (1.17-1.33) [127]. 

Titanacyclopropenes 31 reacts smoothly with dichlorophosphines or phosphorus trichloride with extrusion of the titanium fragment and formation of the phosphirenes 32 or 33, respectively. The transition metal complexes themselves are generated in situ from either a dichlorotitanium complex (Equation 26) or tetraisopropoxytitanium (Equation 27) by reactions with alkynes <19980M2677>. Analogous chemistry can be carried out with zircona-cyclopropenes <1998CC1177>. 

In addition to the chiral BINOL-Iigated dichlorotitanium complex, the variants using diisopropoxytitanium and oxotitanium species are shown to be effective to different degrees. 

A new ansa-complex rac-ethylldene( 1 -n -indenvD-(1-n -tetramethyl Cp) dichlorotitanium was synthe-... 

Gueta-Neyroud T, Tumanskii B, Kapon M, Risen MS. Synthesis and characterization of dichlorotitanium alkoxide complex and its activity in the polymerization of a-olefms. Macromolecules 2007 40 5261-5270. 

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