Effects of substituents on the enrichment of the optical limiting action of novel imidazo[2,1-: B] [1,3,4]thiadiazole fused thiophene-based small molecules

Kakekochi, V.Udayakumar, D.Nikhil, P.P.Chandrasekharan, K.2026-02-052019New Journal of Chemistry, 2019, 43, 23, pp. 9232-924211440546https://doi.org/10.1039/c9nj01100ehttps://idr.nitk.ac.in/handle/123456789/24815The imidazo[2,1-b][1,3,4]thiadiazole (ITD) ring is a fused, planar aromatic heterocyclic system consisting of four heteroatoms with a bridgehead nitrogen atom. In this study, three new donor-acceptor-donor (D-A-D)-type organic molecules (ThITD1-ThITD3) were designed and synthesized, wherein ITD was an electron acceptor unit and the thiophene/phenyl moieties were electron donor units that produced a D-A-D configuration. The thiophene-ITD core structure comprises three different groups viz., thiophene-2-acetonitrile (ThITD1), phenylacetonitrile (ThITD2) and rhodanine-3-acetic acid (ThITD3), and the effect of substituents on the optical and electrochemical properties have been discussed based on structural modifications. The third-order nonlinear optical (NLO) properties analyzed by the Z-scan technique reveal that the molecules exhibit effective two photon absorption (TPA) with ThITD3 possessing substantially higher effective TPA coefficient (?<inf>eff</inf>) than ThITD1 and ThITD2, which is comparable to the reported ?<inf>eff</inf> values. The results unravel that ITD as an acceptor with an appropriate ?-linker will be a promising candidate for application in the field of optoelectronics/photonics. Herein, the thiophene-ITD ring system was explored for NLO applications and reported for the first time. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.imidazo[2,1 b]thiazole derivativeimidazo[2,1 b][1,3,4]thiazole derivativephenylacetonitrilerhodanine 3 acetic acidthiophene 2 acetonitrilethiophene 2 carboxylic acidthiophene derivativethiosemicarbazideunclassified drugArticlecarbon nuclear magnetic resonancechemical structurecolumn chromatographycritical valuecrystallizationdensity functional theoryelectrochemical analysiselectronelectrospray mass spectrometryKnoevenagel condensationlaser safetylight absorptionluminescencemoleculenonlinear systemopticspriority journalproton nuclear magnetic resonancerefraction indexsoftwaresynthesistheoretical modelthermostabilitythin layer chromatographythird order nonlinear opticalEffects of substituents on the enrichment of the optical limiting action of novel imidazo[2,1-: B] [1,3,4]thiadiazole fused thiophene-based small molecules