| Abstract
| - The pseudotetrahedral complexes [Cu(NN)(DPEphos)]BF4, where DPEphos = bis[2-(diphenylphosphino)phenyl]ether and NN = 1,10-phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), 2,9-di-n-butylphenanthroline (3), ortwo dimethylcyanamides (4), and NiCl2(DPEphos) (5) have been synthesized and structurally characterized byX-ray crystallography and their solution properties examined by use of a combination of cyclic voltammetry, NMRspectroscopy, and electronic absorption spectroscopy. Complexes 1−4 possess a reversible Cu(II)/Cu(I) couple atpotentials upward of +1.2 V versus Ag/AgCl. Compounds 1−3 exhibit extraordinary photophysical properties. Inroom-temperature dichloromethane solution, the charge-transfer excited state of the dmp (dbp) derivative exhibitsan emission quantum yield of 0.15 (0.16) and an excited-state lifetime of 14.3 μs (16.1 μs). Coordinating solventsquench the charge-transfer emission to a degree, but the photoexcited dmp complex 2 retains a lifetime of overa microsecond in acetone, methanol, and acetonitrile.
- The structurally characterized pseudotetrahedral complexes [Cu(NN)(DPEphos)]BF4, where DPEphos = bis[2-diphenylphosphino)phenyl]ether and NN = 1,10 phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), or 2,9-di-n-butyl phenanthroline (3), have unusual and contrasting excited-state properties; fluid solutions of 2 and 3 exhibit exceptionally long-lived, high quantum yield emissions that are not quenched in coordinating solvents such as acetone, methanol, and acetonitile, in contradistinction to the behavior of typical copper(I) complexes including 1.
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