Study of the Intersystem Crossing in Ir and Rh Complexes with the Use of Subpicosecond Laser Pulse
There is currently great interest in the photochemical and luminescent properties of transition metal complexes. Because of the interest, Tn←Tl absorption spectra  and the formation time constant  of the lowest triplet state (Tl) for dichlorobis (1,10-phenanthroline) iridium (III) chloride in 95% v/v DMF-H2O or in pure H2O solution were measured with the use of a N2 laser and a mode-locked ruby laser [1,2]. The smaller intersystem crossing rate constant of cis-Ir[Cl2(phen)2]Cl in 45% v/v DMF-H2O mixed solvent (37 ps) than in 95% v/v DMF-H2O mixed solvent (26 ps) was interpreted in terms of the increase crease in 3(π π *) character and the simultaneous decrease in 3(ππ*) character in the lowest triplet state of the model . Presiously the rise times of the luminescence of cis-[RhX2(bpy)2]X (X = CI, Br) where bpy = 2,2’-bipyridine were reported to be 350–630 ns in solution at room and liquid nitrogen temperatures . The authors of the present paper and DEMAS independently noticed that the rise times reported are not the intrinsic ones but are the time constants of the detection photomultiplier system which are determined by the stray capacitance of the detection system and output resistance.
KeywordsLower Triplet State Rise Curve Subpicosecond Pulse Intersystem Crossing Triplet Manifold
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