A Series of Cu I Complexes Containing 1,10‐Phenanthroline Derivative Ligands: Synthesis, Characterization, Photophysical, and Oxygen‐Sensing Properties

Five novel copper(I) complexes with the general formula [Cu(dpephos)(NN)]BF 4 {dpephos = bis[2‐(diphenylphosphanyl)phenyl] ether, NN = 2‐phenyl‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (pip, 1 ), 1‐ethyl‐2‐phenyl‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (epip, 2 ), 2‐(naphthalen‐1‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (nip, 3 ), 1‐ethyl‐2‐(naphthalen‐1‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (enip, 4 ), 2‐(anthracen‐9‐yl)‐1‐ethyl‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline (aeip, 5 )} were rationally designed and synthesized, and these complexes were characterized by 1 H NMR and IR spectroscopy and elemental analysis. X‐ray crystal‐structure analysis of 3 and 4 are also presented. Their photophysical properties at room temperature were examined by using a combination of cyclic voltammetry and electronic absorption spectroscopy. It was found that 1 – 4 display broad‐band emission in the solid state upon excitation at λ = 400 nm, and the emission maxima are located in the range 530–558 nm; the excited‐state lifetimes of these complexes are 8.24, 1.97, 6.99, and 2.43 μs, respectively. As a result, the emission intensity of complexes 1 – 4 is sensitive to oxygen concentration, and they display oxygen‐sensing properties after they are encapsulated into mesoporous silica MCM‐41 or SBA‐15.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)