Abstract: The π-conjugated polymers and oligomers containing bridged biphenyl were important luminescent materials with wide gap. The luminescent property of these materials was relative to the twisted angle between two benzene rings of the bridged biphenyl. The crystal structures of a series of seven-member heterocycle bridged biphenyls were determined by X-ray diffraction. The effect of the bridged atom, the substituent groups in 6,6-position and hydrogen bond (between bridged oxygen atom and hydrogen atom in 2,2’-position of the center biphenyl) on conformation of the bridged biphenyls was discussed.When the bridged bond (—CH2—O—CH2—) changed to—CH2—S—CH2—, the twisted angle between two benzene rings increased by about 12°. The twisted angle also could be influenced by 6,6-substitaent groups, and the twisted angle might increase by about 5°. The hydrogen bond between bridged oxygen atom and hydrogen atom in 2,2’-position of the center biphenyl didn’t affect the conformation of the bridged biphenyls. The bridged atom played an important role for the conformation of the bridged biphenyl of seven-member heterocyle, and the twisted angle also could be influenced lightly by 6,6-substituent groups.

Key words: Seven-member heterocycle, Bridged biphenyl, Conformation, Crystal structure, Twisted angle