In-situ photoisomerization for aggregation-induced emission of dibiphenyl fumaronitrile

The synthesis and photochemical characteristics of a fumaronitrile (FN)-based pi-conjugated molecule, dibiphenyl fumaronitrile (BP-FN), comprising two biphenyl aggregation-induced emission (AIE) activators linked by an FN core were investigated. Upon illumination with a UV light, the emission from the Z-isomer, (Z)BP-FN, was more intense than that of the E-isomer, (E)BP-FN, due to conformational restriction of the former. (E)BP-FN exhibited J-aggregation behavior in mixed THF-H2O solvents when the H2O content exceeded 70 vol%, illustrative of typical AIE characteristics. (Z)BP-FN presented significant aggregation causing quenching in emission when the H2O content exceeded 80 vol %. In-situ photoisomerization of (E)BP-FN to (Z)BP-FN proceeded successfully even in the H2O-induced aggregated state in THF solution; however, the emission of the in-situ photoisomerized (Z)BP-FN aggregates was significantly quenched in solutions with high H2O contents of above 80 vol%. (C) 2015 Elsevier B.V. All rights reserved.