Syntheses and crystal structures of dichlorobis[tetramethyl(phenyl)cyclopentadienyl]titanium(IV) and chlorobis[tetramethyl(phenyl)cyclopentadienyl]-titanium(III)

Dichlorobis[eta(5)-tetramethyl(phenyl)cyclopentadienyl]titanium(IV) (1) and chlorobis[eta(5)-tetramethyl(phenyl)cyclopentadienyl]titanium(III) (2) wer e prepared by the generally known procedures. The X-ray crystal structures of 1 and 2 showed nearly identical Ti-CE (CE - centroid of the cyclopentadi enyl ring) and Ti-Cl distances, the CE-Ti-CE angles and dihedral angles bet ween least-squares planes of the cyclopentadienyl rings to those in [(C5Me5 )(2)TiCl2] and [(C5Me5)(2)TiCl], respectively. ESR spectra of 2 in 2-methyl tetrahydrofuran (MTHF) solutions and glasses revealed that 2 coordinates MT HF to give [(C5Me4Ph)(2)Ti(Cl) (MTHF)] (2a). The formation of 2a in MTHF so lution is completed by lowering temperature to 205 K. A comparison with the known data gives the following order of affinity of [(C5Me4R)(2)TiCl] towa rds MTHF: Ph > SiMe3 > H > Me.