Twist effects on the electronic and photophysical characters of biphenyl and 4,4′-bis(phenylsulfonyl) biphenyl

Sulfonyl groups act as effective breaking points of π-conjugation in 4,4′-bis(phenylsulfonyl) biphenyl. Thereby, a linear relationship between the frontier MOs (HOMOs and LUMOs) energies and twisted angles of the biphenyl core was observed. Moreover, both HOMO and LUMO are stabilized and the triplet transition energy will be increased by the rotation of the central C-C bond in biphenyl core of 4,4′-bis(phenylsulfonyl) biphenyl.117