Bis(triisopropylsilyl)-o-phenylenediamido Complexes of Titanium and Zirconium:  Investigation of a New Ancillary Ligand

From the dilithio reagent o -C 6 H 4 (NLiSi i Pr 3 ) 2 ( 2 ), the new complexes [ o -C 6 H 4 (NSi i Pr 3 ) 2 ] 2 Zr ( 3 ), [ o -C 6 H 4 (NSi i Pr 3 ) 2 ]Zr(O t Bu) 2 ( 4 ), [ o -C 6 H 4 (NSi i Pr 3 ) 2 ]TiCl 2 ( 5 ), and [ o -C 6 H 4 (NSi i Pr 3 ) 2 ]TiMe 2 ( 6 ) have been prepared. X-ray crystallographic and variable-temperature NMR studies characterize these complexes as possessing η 4 -C 6 H 4 (NSi i Pr 3 ) 2 ligands (bonded to the metal via two carbon atoms in the phenylene group), which undergo a η 4 −η 2 fluxional process in solution.