- Photophysical, spectroscopic, and computational studies of a series of Re(I) tricarbonyl complexes containing 2,6-dimethylphenylisocyanide and 5- and 6-derivatized phenanthroline ligands
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The ligand 2,6-dimethylphenylisocyanide (CNx) forms six complexes of the formula [Re(CO)3(CNx)(L)]+, where L = 1,10-phenanthroline (1), 5-chloro-1,10-phenanthroline (2), 5-nitro-1,10-phenarithroline (3), 5-methyl-1,10-phenanthroline (4), 5,6-dimethyl-1,10-phenanthroline (5), and 1,10-phenanthrolinopyrrole (6). The lowest-energy absorption peaks of the complexes red-shift in the order 1 -1 or less from the experimental UV-vis peaks. The complexes undergo reversible reductions and irreversible oxidations. The electronic energy gap increases in the order 33MLLCT energies are within 1100 cm-1 from the experimental emission energies at 77 K. The 77 K emission curve-fitting analysis results agree with the computational assignment of the emitting state as 3MLLCT for 1-5 and 3LC for 6. The experimental 77 K emission energies and the calculated 3MLLCT state energies increase in the order 6 5, 3 2 4, 1. The 77 K emission lifetimes increase upon addition of substituents from 65 μs for 1 to 171 μs for 2, to 230 μs for 4 and 5, and to 322 μs for 3. The emission quantum yields at room temperature in solution are 0.77, 0.78, 0.83, 0.56, and 0.11 for complexes 1, 2, 4, 5, and 6, respectively.
- Villegas, John M.,Stoyanov, Stanislav R.,Huang, Wei,Rillema, D. Paul
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p. 2297 - 2309
(2008/10/09)
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