Synthesis and Structural Characterization of Cu(I) and Ni(II) Complexes that Contain the Bis[2-(diphenylphosphino)phenyl]ether Ligand. Novel Emission Properties for the Cu(I) Species

• Published in: Inorganic chemistry Vol. 41; no. 12; pp. 3313 - 3322
• Main Authors: Kuang, Shan-Ming, Cuttell, Douglas G, McMillin, David R, Fanwick, Phillip E, Walton, Richard A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 17.06.2002
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic0201809

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), or two dimethylcyanamides (4), and NiCl2(DPEphos) (5) have been synthesized and structurally characterized by X-ray crystallography and their solution properties examined by use of a combination of cyclic voltammetry, NMR spectroscopy, and electronic absorption spectroscopy. Complexes 1−4 possess a reversible Cu(II)/Cu(I) couple at potentials upward of +1.2 V versus Ag/AgCl. Compounds 1−3 exhibit extraordinary photophysical properties. In room-temperature dichloromethane solution, the charge-transfer excited state of the dmp (dbp) derivative exhibits an emission quantum yield of 0.15 (0.16) and an excited-state lifetime of 14.3 μs (16.1 μs). Coordinating solvents quench the charge-transfer emission to a degree, but the photoexcited dmp complex 2 retains a lifetime of over a microsecond in acetone, methanol, and acetonitrile.