EFFECT OF THE LIGAND-FIELD STRENGTH ON THE RADIATIVE PROPERTIES OF THE LIGAND-LOCALIZED (3)PI-PI(ASTERISK) STATE OF RHODIUM COMPLEXES WITH 1,10-PHENANTHROLINE - PROPOSED ROLE OF DD STATES

In order to quantify the effect of metal d-orbitals on the radiative properties of the triplet spin sublevels of the ligand-localized 3pipi* State, we have studied the phosphorescence from the ligand-localized 3pipi* state of cis-Rh(CN)2(phen)2Cl and Rh(phen)3Cl3 in the crystalline state at 1.3 K by optical detection of magnetic resonance (ODMR). The ODMR experiments show that only the T(x)-spin sublevel is emissive for cis-Rh(CN)2(phen)2Cl, whereas the T(x) and T(z) sublevels are both emissive for Rh(phen)3Cl3. These experimental results are satisfactorily interpreted in terms of the modulation of the configurational mixing of singlet and triplet dpi* and dd states with the phen-localized pipi* and sigmapi* states induced by changes in ligand-field strength.