Photophysics and photochemistry of biphenylyl triphenylphosphine gold(I) complexes

Biphenylyl triphenylphosphine gold(I) complexes (4-biphenylyl, 4B; 2-biphenylyl, 2B) having the Au–C bond are synthesized. The 4B complex is found to exhibit intense blue phosphorescence (Φp = 0.24 and τT = 117 μs) at room temperature originated from the locally excited triplet of the biphenyl moiety (3LE) in both solid states and a degassed 2-methyltetrahydrofuran solution. 2B, however, is nonluminescent. The homolytic cleavage of the Au–C bond in dichloromethane solution of 4B upon UV irradiation is also reported.