A series of phosphorescent Cu(I) complexes: Synthesis, photophysical feature and optical oxygen sensing performance in MCM-41 silica matrix

This paper synthesized four Cu(I) complexes with different conjugation chains in their diamine ligands for oxygen sensing purpose. The correlation between sensing performance and probe structure was discussed tentatively. Long emission lifetime and large conjugation plane were proved positive to improve sensing performance. [Display omitted] •Four Cu(I) complexes with different diamine conjugation planes were designed.•Their molecular structures and photophysical parameters were discussed.•Small conjugation planes and electron-withdrawing groups increased band gaps.•Their oxygen sensing performance was discussed using a silica matrix MCM-41.•Long lifetime and large conjugation plane improved sensing performance. In this paper, a class of [Cu(N-N)(PPh3)2]BF4 complexes were designed and discussed, where N-N and PPh3 stood for a diamine ligand and triphenylphosphane, respectively. Their molecular structures were confirmed and analyzed by single crystal analysis and density functional theory calculation. Photophysical measurement on these complexes suggested that their energy band gaps were increased by electron-pulling groups. In addition, it was found that their emission was sensitive towards molecular O2, making them potential oxygen sensors. Their oxygen sensing performance was tentatively discussed by doping them into a silica matrix MCM-41. Long emission lifetime and large conjugation plane were proved positive to improve sensing performance. High sensitivity, short response time and good photostability were observed.