Year: 1996
Type: article
Abstract: The excited state properties and reactivity of Rh(phi)2(phen)3+ (phi = 9,10-phenanthrenequinone diimine, phen = 1,10-phenanthroline) were investigated and compared to those of related rhodium(III) and zinc(II) complexes. At 77 K Rh(phi)2(phen)3+ exhibits LC 3ππ∗ dual emission from both phi and phen ligands, whose energies are 2.8 eV and 3.0 eV, respectively, with a biexponential decay that can be fit to 5 ns (98%) and 60 ns (2%) lifetime components. A longer-lived transient is observed by transient absorption both at 77 K and 298 K, which decays monoexponentially with a time constant of 900 ns and 235 ns at each temperature, respectively, in ethanol. The transient can be attained with visible excitation (420 nm to 532 nm) and it is assigned to be intra-ligand charge transfer (ILCT) in nature. It was determined from transient absorption experiments that the ILCT excited state of Rh(phi)2(phen)3+ lies approximately 2.0 eV above the ground state and that it is a powerful oxidizing agent with E12([Rh]3+∗/2+)≈2.0 V versus NHE. The transient absorption experiments with electron donors reveal that the one-electron reduced Rh(phi)2(phen)2+ absorbs at 540 nm with ε ≈ 3300 M−1cm−1.
Source: Inorganica Chimica Acta
Institutions: Columbia University, California Institute of Technology
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,830
OpenAlex ID: W2083693471