Vladislav M. Korshunov , Timofey N. Chmovzh , Ivan V. Shlykov , Mikhail E. Minyaev , Ilya V. Taydakov , Oleg A. Rakitin
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引用次数: 0
Abstract
The Twisted Intramolecular Charge Transfer (TICT) phenomenon can, in some cases, lead to the formation of highly luminescent molecules. Such emitters require donor and acceptor units to be rotationally displaced in the ground state. However, the impact of molecular rotation in the excited state on the photophysical properties of compounds remains insufficiently understood. To bridge this gap, we synthesized and studied a series of donor-acceptor-acceptor (D-A-A1) organic dyes incorporating various chalcogenadiazole acceptors (A) and a cyanoacrylic acid acceptor (A1). Using spectroscopic analysis and TD-DFT calculations, we examined changes in electronic and geometric structures induced by subtle modifications in the acceptor units. Our findings reveal that compounds featuring an additional nitrogen atom in the ortho-position adopt a planar geometry in the first excited singlet state, leading to a blue shift in the emission spectrum while maintaining a high luminescence quantum yield of up to 63 % in cyclohexane. The results demonstrate that a planar excited-state geometry enhances ICT emission efficiency compared to a twisted configuration. Additionally, we identified a distinct solvatochromic behavior in the studied dyes. These insights contribute to a deeper understanding of the TICT mechanism and provide a new strategy for designing highly luminescent organic dyes.
期刊介绍:
Dyes and Pigments covers the scientific and technical aspects of the chemistry and physics of dyes, pigments and their intermediates. Emphasis is placed on the properties of the colouring matters themselves rather than on their applications or the system in which they may be applied.
Thus the journal accepts research and review papers on the synthesis of dyes, pigments and intermediates, their physical or chemical properties, e.g. spectroscopic, surface, solution or solid state characteristics, the physical aspects of their preparation, e.g. precipitation, nucleation and growth, crystal formation, liquid crystalline characteristics, their photochemical, ecological or biological properties and the relationship between colour and chemical constitution. However, papers are considered which deal with the more fundamental aspects of colourant application and of the interactions of colourants with substrates or media.
The journal will interest a wide variety of workers in a range of disciplines whose work involves dyes, pigments and their intermediates, and provides a platform for investigators with common interests but diverse fields of activity such as cosmetics, reprographics, dye and pigment synthesis, medical research, polymers, etc.