Photoreactivity of (HBpyrazolyl(3)) TiCl3 and (C5H5)TiCl3 initiated by ligand-to-metal charge transfer excitation

The isoelectronic complexes LTiiv Cl-3 with L- = C5H5- and HBPz(3)(-) (hydr otrispyrazolylborate) show long-wavelength LMCT absorptions lambda(max) = 3 82 and 314 nm, respectively. LMCT excitation is assumed to generate L radic als and TiCl3 in the primary photochemical step. In CHCl3 solution TiCl3 is reoxidized by the solvent to TiCl4 which is formed with phi = 0.003 at lam bda(irr) = 405 nm (L- = C5H5-) and phi = 0.002 at lambda(irr) = 366 nm (L- = HBPz(3)(-)). (C) 1998 Elsevier Science S.A. All rights reserved.