Dataset Information

Light-Responsive Oligothiophenes Incorporating Photochromic Torsional Switches.

ABSTRACT: We present a quaterthiophene and sexithiophene that can reversibly change their effective π-conjugation length through photoexcitation. The reported compounds make use of light-responsive molecular actuators consisting of an azobenzene attached to a bithiophene unit by both direct and linker-assisted bonding. Upon exposure to 350 nm light, the azobenzene undergoes trans-to-cis isomerization, thus mechanically inducing the oligothiophene to assume a planar conformation (extended π-conjugation). Exposure to 254 nm wavelength promotes azobenzene cis-to-trans isomerization, forcing the thiophenic backbones to twist out of planarity (confined π-conjugation). Twisted conformations are also reached by cis-to-trans thermal relaxation at a rate that increases proportionally with the conjugation length of the oligothiophene moiety. The molecular conformations of quaterthiophene and sexithiophene were characterized by using steady-state UV-vis spectroscopy, X-ray crystallography and quantum-chemical modeling. Finally, we tested the proposed light-responsive oligothiophenes in field-effect transistors to probe the photo-induced tuning of their electronic properties.

SUBMITTER: Jozeliunaite A

PROVIDER: S-EPMC9828566 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Light-Responsive Oligothiophenes Incorporating Photochromic Torsional Switches.

Jozeliūnaitė Augustina A Rahmanudin Aiman A Gražulis Saulius S Gražulis Saulius S Baudat Emilie E Sivula Kevin K Fazzi Daniele D Orentas Edvinas E Sforazzini Giuseppe G

Chemistry (Weinheim an der Bergstrasse, Germany) 20221031 65

We present a quaterthiophene and sexithiophene that can reversibly change their effective π-conjugation length through photoexcitation. The reported compounds make use of light-responsive molecular actuators consisting of an azobenzene attached to a bithiophene unit by both direct and linker-assisted bonding. Upon exposure to 350 nm light, the azobenzene undergoes trans-to-cis isomerization, thus mechanically inducing the oligothiophene to assume a planar conformation (extended π-conjugation). E ...[more]

PMID: 36136376

Similar Datasets

Project description:Oligothiophenes incorporating MM quadruple bonds have been prepared from the reactions between Mo(2)(TiPB)(4) (TiPB = 2,4,6-triisopropyl benzoate) and 3',4'-dihexyl-2,2'-:5',2''-terthiophene-5,5''-dicarboxylic acid. The oligomers of empirical formula Mo(2)(TiPB)(2)(O(2)C(Th)-C(4)(n-hexyl)(2)S-(Th)CO(2)) are soluble in THF and form thin films with spin-coating (Th = thiophene). The reactions between Mo(2)(TiPB)(4) and 2-thienylcarboxylic acid (Th-H), 2,2'-bithiophene-5-carboxylic acid (BTh-H), and (2,2':5',2''-terthiophene)-5-carboxylic acid (TTh-H) yield compounds of formula trans-Mo(2)(TiPB)(2)L(2), where L = Th, BTh, and TTh (the corresponding thienylcarboxylate), and these compounds are considered as models for the aforementioned oligomers. In all cases, the thienyl groups are substituted or coupled at the 2,5 positions. Based on the x-ray analysis, the molecular structure of trans-Mo(2)(TiPB)(2)(BTh)(2) reveals an extended Lpi-M(2)delta-Lpi conjugation. Calculations of the electronic structures on model compounds, in which the TiPB are substituted by formate ligands, reveal that the HOMO is mainly attributed to the M(2)delta orbital, which is stabilized by back-bonding to one of the thienylcarboxylate pi* combinations, and the LUMO is an in-phase combination of the thienylcarboxylate pi* orbitals. The compounds and the oligomers are intensely colored due to M(2)delta-thienyl carboxylate pi* charge transfer transitions that fall in the visible region of the spectrum. For the molybdenum complexes and their oligomers, the photophysical properties have been studied by steady-state absorption spectroscopy and emission spectroscopy, together with time-resolved emission and transient absorption for the determination of relaxation dynamics. Remarkably, THF solutions the molybdenum complexes show room-temperature dual emission, fluorescence and phosphorescence, originating mainly from (1)MLCT and (3)MM(deltadelta*) states, respectively. With increasing number of thienyl rings from 1 to 3, the observed lifetimes of the (1)MLCT state increase from 4 to 12 ps, while the phosphorescence lifetimes are approximately 80 micros. The oligomers show similar photophysical properties as the corresponding monomers in THF but have notably longer-lived triplet states, approximately 200 micros in thin films. These results, when compared with metallated oligothiophenes of the later transition elements, reveal that M(2)delta-thienyl pi conjugation leads to a very small energy gap between the (1)MLCT and (3)MLCT states of <0.6 eV.

Dataset Information

Light-Responsive Oligothiophenes Incorporating Photochromic Torsional Switches.

Publications

Light-Responsive Oligothiophenes Incorporating Photochromic Torsional Switches.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets