Mesoporous silica doped with a chemosensor based on phosphorescent copper(I) complex: Synthesis, characterization, photophysical property, and sensing behavior towards molecular oxygen

In this paper, we report the synthesis, crystal structure, photophysical properties, and electronic nature of a phosphorescent Cu(I) complex of [Cu(OP)(PPh3)2]BF4, where OP and PPh3 stand for 2-(5-phenyl-[1,3,4]oxadiazol-2-yl)-pyridine and triphenylphosphine, respectively. [Cu(OP)(PPh3)2]BF4 is a yellow-emitting complex with a phosphorescence peaking at 552 nm and a long excited state lifetime of 83.5 μs under N2 atmosphere. Density functional calculation reveals that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. We dope [Cu(OP)(PPh3)2]BF4 into a mesoporous silica matrix of MCM-41, hoping to explore the possibility of using the doped silica as an oxygen sensing material. The resulted samples exhibit a maximum sensitivity of 4.48 towards oxygen with short response time due to the large surface-area-to-volume ratio of MCM-41 matrix, and no photobleaching is detected in these samples.