Configuration interaction study on the conformational and optical properties of excited furan oligomers

Conformational and optical properties of bifuran (BFU) and terfuran (TFU) in their ground states (S0) and the first singlet excited states (S1) were investigated by using configuration interaction/singles (CIS), TD-B3LYP and ZINDO approaches. The results show BFU and TFU have both planar and distorted stable conformers in their S0 states, whereas have planar structure in the S1 states; BFU and TFU have high inter-ring torsional flexibilities in both the ground-states and the S1 states; the cis-conformers show different optical properties compared to the trans-conformers. These results should be helpful in further research on oligofurans as molecular electronics.