A design strategy has been proposed to utilize structure-driven solution and solid-state fluorescence emission of polynitrogen atoms. The strategy uses benzimidazole as the electron donor and pyridine as the electron acceptor to construct D-A-type cyanopyridine ethylene molecules. Theoretical calculations reveal that compound 1 has energy-close isomers in dilute solutions, with planar conformation in S0 and S1 states, reducing molecular motion and thus enhancing radiation efficiency (quantum yield up to 42.7%). Conversely, the distorted cyanobenzene structure reduces the quenching effect of pi-pi stacking alignment, and hydrogen bonding between molecules limits molecular vibration and rotation, ultimately leading to strong emission in the solid state (quantum yield up to 27.4%). These dual-state luminescence systems have wide-ranging potential applications in information encryption and temperature sensors. Solution and solid-state fluorescence emission achieved through constructing D-A-type cyanopyridine ethylene molecules.
Funding Agencies|Fundamental Research Funds for the Central Universities [2232022A-03, 2232022G-04]; National Natural Science Foundation of China [22375036]; Natural Science Foundation of Shanghai [21ZR1402000]; International Cooperation Fund of Science and Technology Commission of Shanghai Municipality [21130750100]; Swedish Research Council [2020-04600, 2022-06725]; Olle Engkvists Stiftelse (Sweden) [212-0136]