Highly Emissive (PPh)₃CuBr by Trace (BINAP)₂Cu₂Br₂ Doping and Their Application in Dichloromethane Detection

A trace (BINAP)(2)Cu2Br2-doped TPP3CuBr complex TPP3CuBr:x(BINAP)(2)Cu2Br2 (complex 1) was synthesized, which exhibits strong phosphorescence with a yellow-green emission peak at 525 nm and a shoulder peak at 560 nm. Nevertheless, no emissions were observed for either pure (BINAP)(2)Cu2Br2 or pure TPP3CuBr. The plausible mechanism is that the incorporation of (BINAP)(2)Cu2Br2 into the rigid environment provided by the TPP3CuBr matrix effectively restricts the variation of (BINAP)(2)Cu2Br2 molecules, thus reducing nonradiative transitions. On the other hand, pi-pi stacking and hydrogen bond interactions may influence the conformation of (BINAP)(2)Cu2Br2, potentially leading to more efficient phosphorescence. Interestingly, complex 1 was found to have a sensitive response to dichloromethane (DCM) solvent. An obvious blue shift in emission was observed when complex 1 was exposed to a DCM atmosphere. Moreover, after removal from the DCM atmosphere, complex 1 can be restored to its initial state. Additionally, complex 1 demonstrated remarkable attributes, including high sensitivity, selectivity, and stability. Incorporating (BINAP)(2)Cu2Br2 into the TPP3CuBr matrix leads to highly efficient emission. The resulting emitter exhibits reversible vapochromism in response to dichloromethane with excellent sensitivity and selectivity.