Reactions of Heteroallenes with Salan-based Ti(IV) Complexes: A Joint Experimental and Computational Study.

The reaction of Ti(NMe 2 ) 4 with the salan ligand precursor H 2 N 2 O 2 H 2 led to the formation of [(L*)Ti(NHMe 2 ) 2 ] (L*=N 2 O 2 4- ) that forms [(H 2 N 2 O 2 )TiCl 2 ] upon reaction with two equiv. of Me 3 SiCl. [(L*)Ti(py) 2 ] was obtained from the reaction of [Ti(N t Bu)Cl 2 (py) 3 ] with the sodium salt H 2 N 2 O 2 Na 2 . Treatment of [(L*)Ti(NHMe 2 ) 2 ] with two equiv. of t BuNCO led to the insertion of the isocyanate molecules into the Ti-N salan bonds with the formation of [{L*(N( t Bu)CO) 2 }Ti]. Conversely, the reaction of [(H 2 N 2 O 2 )Ti(O i Pr) 2 ] with two equiv. of t BuNCO led to the insertion of one isocyanate molecule into a Ti-N salan bond with the formation of [{(HN 2 O 2 )(N( t Bu)CO)}Ti(O i Pr)]. Computational studies were performed to gain insight into the reactivity of isocyanates with salan-based Ti(IV) complexes.