Reaction of Titanocene Alkyls with Pyridines; A Novel Type of Cyclometallation Reaction

Reaction of Cp2TiR (R = alkyl) with 2-substituted-pyridines and with quinolines leads to α-metallation of these ligands with formation of triangular titanocycles containing TiIII. Proof of the metallation at the α-position comes from reactions of the complexes formed with I2 and D2O/DCl which yield the corresponding iodo- and deutero-pyridine and -quinoline derivatives. Reaction of Cp2TiR with the structurally related ligand benzalaniline leads to a side-on coordinated benzalaniline complex of titanocene. Reactions of this diamagnetic complex with I2, CO2 and H2 are described.