Experimental and theoretical studies of the effect of molecular conformation on the photophysical properties in the pyrene system

Disordered motion is an intrinsic property of molecules. The use of controllable molecular motion can not only achieve interesting molecular geometry, but can also induce novel opto-electronic behaviour. Herein, a set of pyrene-based compounds were synthesized to realize an observable molecular motion. 2,5-Dimethoxyphenyl unit (s) were introduced at the pyrene core, which lead to different molecular conformations. Furthermore, the detailed molecular geometries of the compounds were investigated by NMR spectroscopy and DFT calculations. In addition, the photophysical properties of these compounds were investigated in order to understand the relationship between the molecular conformations and the photophysical properties. The diversiform of molecular conformations can cause a broadened FWHM emission in organic luminescence materials.