Boron carbon oxyphosphide heterostructured nanodots with phosphate tunable emission for switchable dual detection channels of 6-mercaptopurine assay.

The preparation of boron-carbon-oxygen (BCO)-based heterostructure needs commonly high temperature, high pressure and/or auxiliary strong oxidant. And the BCO-based probe for the sensing application is still rare owing to their few active groups, low quantum yield or missing specificity. Exploring BCO-based heterostructured probe via simple routes and application in sensing, therefore, is highly challenging. Herein, we proposed a novel boron-carbon-phosphorus-oxygen (BCPO) nanodot with phosphate tunable near-ultraviolet emission performance and narrow full width at half maximum by a facile, green and gentle synthesis process. The BCPO not only exhibits a distinctive colorimetric response to 6-mercaptopurine (6-MP), but also displays 6-MP-sensitive photoluminescence quenching. Thus, dual detection channels for 6-MP based on BCPO probe have been developed, and the mechanism has been speculated. Enrichment-electron of the 6-MP can be adsorbed at the boron vacancy orbits of the BCPO by the chemical action. The formation of 6-MP/BCPO complexes trigger the efficient photoluminescence quenching and light-absorbing enhancing of the BCPO, owing to the synergistic effect of the acceptor-excited photo-induced electron/energy transfer, inner filter effect and p/π-π conjugated stacking. Furthermore, the presence of ClO anion efficaciously sparks the release of the 6-MP molecule from the 6-MP/BCPO complexes, thereby a rapid photo-switch of the BCPO for the 6-MP has been developed. Thus, this study can not only guide the further rational design of the BCPO probe, but also inspire the in-depth application of the BCPO and other nanomaterial-based probes.