Intramolecular charge transfer induced emission from triphenylamine-o-carborane dyads

Two novel triphenylamine-o-carborane dyads with donor-acceptor architectures were designed and synthesized. The photophysical properties were thoroughly investigated. The results demonstrated that triphenylamine-o-carborane dyads presented locally excited (LE) emission and twisted intramolecular charge transfer (TICT) induced emission in various polar solvents, in which LE emission was not dependent on the solvent polarities and TICT emission was consistent with the solvent polarities. The solvent-dependent TICT emission with a large bathochromic shift exhibited a dramatic decrease in emissive efficiency with increasing the solvent polarity. More importantly, the triphenylamine-o-carborane dyads in solid states exhibited highly efficient ICT emissions, in which the ICT characteristics were confirmed by the experimental data and the density function theory (DFT) calculation results.