34312-77-1Relevant articles and documents
Nonlinear optical properties of novel thiophene derivatives: Experimental and ab initio time-dependent coupled perturbed Hartree-Fock studies
Karna, Shashi P.,Zhang, Yue,Samoc, Marek,Prasad, P. N.,Reinhardt, Bruce A.,Dillard, Ann G.
, p. 9984 - 9993 (1993)
We report in this paper experimental and theoretical studies of the nonlinear optical properties of a new class of compounds which differ from traditional second-order molecules in the sense that a commonly used electron donor chromophore is replaced by a thiophene ring.The molecular second-order nonlinear optical coefficients, β, is determined by the electric field-induced second-harmonic generation technique, for 2-nitro-1-(2-thienyl)ethene and 4-nitro-1-(2-thienyl)-1,3-butadiene are, respectively, 1 and 3 times that of para-nitroaniline.Ab initio time-dependent coupled perturbed Hartree-Fock results are in agreement with the experimental findings.A Mulliken population analysis indicates that the sulfur atom in the thiophene ring acts as an electron donor.Both the experimental and the theoretical results confirm that a thiophene ring acts as an efficient donor, giving rise to highly efficient second-order nonlinear optical properties.We also show that with this type of chromophore one can use a thiophene oligomer, in place of a thiophene monomer, to amplify the nonlinearity.
Exploiting the chiral ligands of bis(Imidazolinyl)-and bis(oxazolinyl)thiophenes—Synthesis and application in Cu-catalyzed friedel–crafts asymmetric alkylation
Al-Majid, Abdullah Mohammed,Alammari, Abdullah Saleh,Alshahrani, Saeed,Barakat, Assem,Haukka, Matti,Islam, Mohammad Shahidul
, (2021/12/17)
Five new C2-symmetric chiral ligands of 2,5-bis(imidazolinyl)thiophene (L1–L3) and 2,5-bis(oxazolinyl)thiophene (L4 and L5) were synthesized from thiophene-2,5-dicarboxylic acid (1) with enantiopure amino alcohols (4a–c) in excellent optical purity and chemical yield. The util-ity of these new chiral ligands for Friedel–Crafts asymmetric alkylation was explored. Subse-quently, the optimized tridentate ligand L5 and Cu(OTf)2 catalyst (15 mol%) in toluene for 48 h promoted Friedel–Crafts asymmetric alkylation in moderate to good yields (up to 76%) and with good enantioselectivity (up to 81% ee). The bis(oxazolinyl)thiophene ligands were more potent than bis(imidazolinyl)thiophene analogues for the asymmetric induction of the Friedel–Crafts asymmetric alkylation.
Palladium-Catalyzed Formal (3 + 2) Cycloaddition Reactions of 2-Nitro-1,3-enynes with Vinylaziridines, -epoxides, and -cyclopropanes
Drew, Melanie A.,Tague, Andrew J.,Richardson, Christopher,Pyne, Stephen G.,Hyland, Christopher J. T.
supporting information, p. 4635 - 4639 (2021/06/28)
A two-step Pd-catalyzed (3 + 2) cycloaddition/HNO2 elimination reaction sequence has been developed to give novel cyclic 1,3-dien-5-yne systems from Pd-stabilized zwitterionic 1,3-dipoles and 2-nitro-1,3-enyne substrates. The process is highly atom-efficient and tolerates the reaction of 2-vinyloxirane, 1-tosyl-2-vinylaziridine, and diethyl 2-vinylcyclopropane-1,1-dicarboxylate derived 1,3-dipoles with a variety of 2-nitro-1,3-enyne substrates. The stereochemistry of the intermediate (3 + 2) cycloadducts was determined by single crystal X-ray analysis. Furthermore, a selective kinetic elimination of the cycloadduct with an antiperiplanar relationship between the NO2 group and the participating hydrogen was demonstrated, allowing for efficient isolation of a single diastereoisomer of the cycloadduct.