SPIN CHEMISTRY OF RU(II)-TRISDIIMINE COMPLEX PHOTOOXIDATION IN MAGNETIC-FIELDS UP TO 17.5 TESLA

The magnetic field dependence of the efficiency of cage escape eta(ce) , which is due to the magnetic field and spin control of the effective rate of electron backtransfer in geminate pairs of photogenerated Ru( III) complexes and electron acceptor radicals, has been measured for R u(bpy)32+ and Ru(phen)32+ over the entire field range from 0 to 17.5 T . These magnetic field dependent data on eta(ce), together with the ex perimental values of the g-tensor components of the Ru(III) complex, a llow us to evaluate unambiguously and without recourse to supplementar y information, the absolute values of the rate constants of cage escap e (k(ce)), (spin-conserving) backward electron transfer (k(bet)) and e lectron spin relaxation time tau(s) of the Ru(III) complex.