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Tunable Photophysical Properties of Thiophene Based Chromophores: Conjoined Experimental and Theoretical Investigation
摘要： In this paper we report synthesis and photophysical properties of six novel thiophene derivatives (ThD) with D-π-A structure. The subject of this work are three nitrophenyls (1) BT-Th-NO2 and three benzonitriles (2) BT-Th-CN, substituted at different positions of aromatic ring ((a) ortho-, (b) meta- or (c) para-). Dyes were obtained using simple three-step synthesis and their chemical structures were confirmed by 1H and 13C NMR, IR as well as high resolution mass spectrometry. The influence of positional isomerism on optical properties has been explored experimentally and theoretically. The photophysical properties were investigated using steady-state as well as time-resolved spectroscopy and the obtained results were supported by quantum-chemical calculations. TD-DFT calculations indicated that charge-transfer strength can be correlated with the observed optical properties. In addition, the influence of the acceptor position on photoluminescence spectra, fluorescence quantum yields and emission lifetimes was specified. We show that ThD optical properties can be tuned in wide spectral range by the change made in only single step of synthesis reaction.
关键词： push-pull chromophores,Thiophene derivatives,TD-DFT,quantum yield,charge transfer
更新于2025-11-19 16:46:39
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Dicyanovinyl substituted push–pull chromophores: effect of the central C=C/phenyl spacers, crystal structures and application in hydrazine sensing
摘要： To discern the distinctive effect of C=C bond and phenyl bridge on the photophysical and chemical properties of D?π?A molecular systems, three new dicyanovinyl substituted push–pull chromophores 1-3 containing either a C=C bond or a phenyl ring as the central π?linker, were synthesized by Suzuki-Miyaura and Knoevenagel reactions. Together with the counterpart of 1 developed by Zhang’s group (TPE-z), their optical properties and single crystal structures were systematically and comparatively investigated. Notably, the simple π–extension of a C=C linker to a phenyl ring between electron-donor and -acceptor moieties could greatly affect the photophysical properties of chromophores, particularly leading to significant hypsochromic shifts in both absorption and emission spectra. Meanwhile, as a node of twisted sections in chromophores, the C=C bond was demonstrated to play an important role in the nonradiative relaxation of excited states, as compared to the rigid phenyl spacer. Moreover, the three chromophores were found to display spectral responses to hydrazine with slightly different sensitivities and visual detection of hydrazine in gaseous state was achieved via using readily fabricated paper test strips.
关键词： C=C bond,hydrazine sensing,phenyl bridge,push-pull chromophores,photophysical properties,Dicyanovinyl
更新于2025-09-19 17:15:36
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Combined SERS/DFT studies of push–pull chromophore self-assembled monolayers: insights into their surface orientation
摘要： Having clear and deep information on the surface/interface of deposited molecules is of crucial importance for the development of efficient optoelectronic devices. This paper reports on a joint experimental/theoretical hybrid approach based on Raman spectroscopy in order to provide information on the orientation of push–pull chromophores deposited onto a gold surface. In addition, several parameters can strongly control or impede the orientation of such molecules on the surface such as: the molecular structure, the surface itself, the method of deposition and the solvents used. From this approach, additional information has been highlighted such as perpendicularly depositing the molecule on the surface, the bithiophene compounds displaying more solvent effects compared to terthiophene molecules and so on. According to the results, the joint SERS/DFT study proves to be an effective tool for probing the arrangement of push–pull chromophores and selecting the right experimental conditions to tune the surface properties.
关键词： SERS,DFT,push–pull chromophores,surface orientation,self-assembled monolayers
更新于2025-09-12 10:27:22