Complexes of [(dadi)Ti(L/X)]m That Reveal Redox Non-Innocence and a Stepwise Carbene Insertion into a Carbon–Carbon Bond

The addition of donors to (dadi)­Ti­(THF) (1-THF, dadi = [{−CH═N­(1,2-C6H4)­N­(2,6-iPr2–C6H3)}2]n) afforded the adducts [(dadi)­Ti­(L/X)]m (1-L, m = 0, N2CPh2; m = −1, X = Cl–, N3–, OiPr–, CH3–, neoPe–, CH═CH2–, CCPh–, CCTMS–, H­(D)−). In all adducts, the chelate was in the (dadi)4– redox state. For certain anions, evidence for intimate binding of the Li+ counterion was explored spectroscopically. Treatment of 1-THF with PhHCN2, yielded {PhC3H3(-NC6H4-2-NAr)2}­Ti­(THF) (3, Ar = 2,6-iPr2–C6H3), which contains a cyclopropanated dadi ligand. The mechanism was explored by calculations, and the addition of Ph2CN2 to 3 produced a nacnac derivative, {PhC­(CHNC6H4-2-NAr)2}­Ti­(η2-HNNCPh2) (4, Ar = 2,6-iPr2–C6H3), generated via hydrogen transfer from the cyclopropane.