Tuning for visible fluorescence and near-infrared phosphorescence on a unimolecular mechanically sensitive platform via adjustable CH-π interaction

CH-π interaction-assisted alignment of organic conjugated systems has played an important role to regulate molecular electronic and photophysical properties, whereas harnessing such a smart noncovalent interaction into the tuning of unimolecular complex emissive bands covering a wide spectral region remains a challenging research topic. Since the tuning for visible and near-infrared emissive properties in a single π-functional platform relates to its multicolor luminescent behaviors and potential superior application in analysis, bioimaging, and sensing, herein, we report a proportional control of the singlet and triplet emissions that cover visible and near-infrared spectral regions, respectively, can be straightforwardly achieved by CH-π interaction-assisted self-assembly at the unimolecular level. Employing an octathionaphthalene-based single luminophore as a prototype, we find that a strength-adjustable CH-π interaction-assisted self-assembly can be established in mixed DMF/H₂O and in the film state. The hybridization of planar local excited and intramolecular cha transfer transitions occurs on the basis, allowing a competitive inhibition to the intersystem crossing process to generat complex emission composed of visible fluorescence and near-infrared phosphorescence. Furthermore, reversi mechanochromic and mechanoluminescent conversions of the corresponding solid sample can both be observed to rely o corresponding self-assembly alternation. These results can probably provide new visions for the development of future intellig and multifunctional luminescent materials.