UV-VISIBLE ABSORPTION AND EMISSION SPECTROSCOPIC STUDIES OF THE COMPLEXES -[RU(NH3)(4)P(III)H2O](2+),P(III)=P(OR)(3),P(R)(3)

The studied complexes show a strong absorption band at about 315 nm as signed to the (1)A(1)-->(1)E(1) electronic transition. Spectral deconv olution analysis of the absorption spectra shows the existence of a we ak absorption band in the range 380-390 nm which has been assigned to the symmetry forbidden (1)A(1)-->(1)A(2) electronic transition. The co mplexes trans-[Ru(NH3)(4)P(III)(3)H2O](2+) are luminescent at room tem peratura (298 K) with emission quantum yields in the 1.0 x 10(-3) (P(I II) = P((OC3H7)-C-i)(3)) to 8.4 x 10(-2) (P(III) = P(OC4H9)(3)) range, and emission maximum around 408 nm for most of the complexes studied. The luminescence decay of the complex trans-[Ru(NH3)(4)P(OC4H9)(3)H2O ](2+) exhibits biexponential character, such behavior being ascribed t o an interconversion process between the (1)E(1) and (1)A(2) singlet e xcited states prior to the deactivation to the ground state. Analysis of temperature dependence of the decay parameters indicates that the e nergy difference between these excited states in trans-[Ru(NH3)(4)P(OC 4H9)(3)H2O](2+) should lie between 17 and 25 kJ mol(-1).