Photoluminescent Phosphinine Cu(I) Halide Complexes: Temperature Dependence of the Photophysical Properties and Applications as a Molecular Thermometer.

Luminescent thermometers have attracted much attention, because of their fast response, high sensitivity, and noninvasive operation, relative to other traditional thermometers. The extensive studies on the temperature-dependent luminescent properties of Cu(I) complexes make this low-cost metal source a promising candidate as a component of thermometers. Herein, we prepared three luminescent phosphinine Cu(I) complexes whose emission lifetimes are precisely dependent on the temperature variations. For practical utilization, sensor films have been fabricated by doping these Cu(I) complexes into the matrices of polyacrylamide. These films not only exhibit excellent linear correlations between the temperature and emission lifetime over the wide range of 77-337 K, but also show high sensitivity (with the best one to -6.99 μs K). These are essential factors for the application in luminescent molecular thermometers. Moreover, the emission mechanism for these Cu(I) complexes are rationalized by the combination of experimental and theoretical results.