Theoretical study on geometrical structure and electronic spectrum properties of two stable conformers of boron hydroxyphenylpyridine excimers

Geometrical structures of boron hydroxyphenylpyridine (dppyBF) excimers have been optimized at the B3LYP/6-31G* levels of theory. Two stable excimer conformers, crossed and parallel-displaced configuration, were obtained with similar energies. Electronic spectrum properties of two conformers were studied by TD-DFT methods. It is shown that both excimer present red-shifted emission peaks relative to that of monomer (dppy)BF, which mainly originate from the lowest unoccupied molecular orbital (LUMO) of excited (dppy)BF* segment to the highest occupied molecular orbital (HOMO) of ground (dppy)BF segment in excimer.