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

Abstract

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-ocarborane 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.

Weak interactions but potent effect: tunable mechanoluminescence by adjusting intermolecular C–H⋯π interactions

“…7b – d and diphenylamine derivatives are typical TICT donor moieties. 19 Therefore, a mechanoluminescent material with tunable emission bands might be achieved in an asymmetrical diphenylketone (acceptor) cored molecule flanked either side by triphenylphosphine (aiding ML properties) and diphenylamine (aiding TICT properties) moieties in a donor–acceptor type molecular system (CDpP). To satisfy this, herein we describe the synthesis of CDpP ( Fig.…”

Recent Progress in the Development of Solid‐State Luminescent o‐Carboranes with Stimuli Responsivity

“…It is noteworthy that ICT involving the o ‐carborane unit and the aryl moiety should play an important role in AIE. Other types of TPA‐substituted carboranes, 10 and 11 , were reported by Lai et al . meta ‐Substituted 10 and para ‐substituted 11 demonstrated AIE behavior similar to those of the above compounds.…”

Effect of Planarity of Aromatic Rings Appended to o-Carborane on Photophysical Properties: A Series of o-Carboranyl Compounds Based on 2-Phenylpyridine- and 2-(Benzo[b]thiophen-2-yl)pyridine

“…Introduction of this unit to an aryl group leads to the formation of a donor-acceptor conjugated system owing to the strongly electron-withdrawing C atoms and highly delocalized 3D aromaticity of the o -carborane cage. Such a good conjugated system results in intramolecular charge transfer (ICT) transition between the two components [29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51]. Thus, the unprecedented luminescent properties of numerous o -carboranyl compounds emerge from the ICT-based emissive features [29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57].…”

“…This phenomenon depends on the dihedral angle between the diazaboryl moiety and C–C bond of o -carborane. In addition, various fluorophores possessing o -carboranyl groups have exhibited multiple photoluminescence (PL) originating from the alternation of the twisted ICT state [43,44,45,46,47,48,49,50,51]. These results clearly indicate that structural features can play an important role in controlling the intrinsic photophysical and electronic characteristics of o -carboranyl compounds.…”