Synthesis, crystal structure, property research, and DFT calculation of 2,3-diphenylfuro[3,2-b]quinoxaline

The title compound is obtained via the intramolecular condensation of 3-(2-oxo-1,2-diphenylethyl)quinoxalin-2(1H)-one in the presence of excessive boron trifluoride etherate and characterized by 1H NMR, 13C NMR, IR, and EI-MS. The solution-based and solid-state fluorescence along with the electrochemical property are studied in detail. The unique herring-bone arrangement which is revealed by the X-ray crystallography should account for the intense solid-state fluorescence. The theoretic calculations are employed to clarify the origin of the large Stokes shift and the positive solvatochromism in view of the geometric relaxation and the transition feature.