5496-33-3Relevant articles and documents
Synthesis, structures, and two-photon absorption properties of two new heterocycle-based organic chromophores
Yan, Yun-Xing,Fan, Hai-Hua,Lam, Chi-Keung,Huang, Hong,Wang, Jing,Hu, Sheng,Wang, He-Zhou,Chen, Xiao-Ming
, p. 1614 - 1619 (2006)
Two new heterocycle-based two-photon absorption chromophores, 4-[4-(4,5-diphenyl-1H-imidazol-2-yl)styryl]-pyridine (2) and (E)-4-{[2-(1H-benzimidazol-2-yl)vinyl]styryl}-N-methylpyridinium iodide (4), have been synthesized and characterized. The two molecules possess A-π-A′ structures. A π-deficient heteroaromatic ring (benzimidazole, 4,5-diphenyl-1H-imidazole) is used as an acceptor (A), and a pyridine ring is used as another acceptor (A′). One-photon-excited fluorescence, one-photon-fluorescence quantum yields, two-photon-excited fluorescence, and two-photon absorption cross-sections were investigated. Pumped with 740 and 800 nm laser excitation, compounds 2 and 4 had two-photon absorption cross-sections (41 and 38 GM) and two-photon-excited fluorescence (511 and 601 nm) in DMF, respectively. The crystal structure of compound 4 was determined by using X-ray single-crystal diffraction analysis.
Topology-Reset Execution: Repeatable Postcyclization Recyclization of Cyclic Polymers
Honda, Satoshi,Oka, Minami,Takagi, Hideaki,Toyota, Taro
, p. 144 - 148 (2019)
Repeatable topological transformation of polymers for the modulation of material functions is a challenge. We have developed a method for repeatedly resetting a cyclic macromolecular architecture to a linear architecture by photostimulation, namely, topol
Tunable single and dual emission behavior of imidazole fluorophores based on D-π-A architecture
Nagarajan,Velmurugan,Venuvanalingam,Renganathan
, p. 36 - 48 (2014)
A series of three D-π-A molecules containing 4,5-diphenyl-1H-imidazole moiety as the donor (D) with cyanoacetic acid, rhodanine-3-acetic acid and 4-nitrophenyl acetonitrile as the acceptor (A) connected by a biphenyl bridge have been synthesized and characterized. Crystallography of BIC shows C4-phenyl group to be twisted nearly perpendicular to the imidazole unit and the remaining groups are in plane. The absorption spectra of the compounds are dominated by intramolecular charge transitions that arise from the imidazole core to the acceptor groups. The compounds display distinct dual and single emission behavior in different solvent environments, namely locally excited (LE ～ 430 nm) and intramolecular charge transfer (ICT ～ 550 nm). The Lippert-Mataga analysis suggested that the excited state dipole moment of ICT band is higher than the LE band. The influence of general and specific solvent effects on photophysical properties of the fluorophores was discussed with Catala?n four parameter and Kamlet-Taft three parameter solvent scales. These results suggest that the major influence from solvent dipolarity takes part in a prominent role on changing the emission behavior of the compounds. The quantum yield of the compounds ranged between 0.07 and 0.55 in different solvents and it was shown to depend on the substitution pattern most notably that based on acceptor groups. All the compounds exhibit two lifetimes in the singlet excited state corresponding to LE state (short lived) and ICT state (long lived). In addition, the triplet state absorption properties of the compounds are also investigated by transient absorption measurement. The geometric structure and electronic structure of the molecules in the ground state is studied with DFT methods, whereas the energies of the lowest singlet excited states are calculated by employing TD-DFT methods. The results show that most prominent bands in acetonitrile solvent with higher oscillator strength for BIC, BIN and BIR are due to LE.
Synthesis and characterization of a new polymeric catalyst and used for the synthesis of imidazole derivatives
Karimi Zarchi, Mohammad Ali,Behboodi, Kazem,Mirjalili, Bibi Fatemeh
, p. 4929 - 4942 (2021/09/06)
Cross-linked poly (4-vinylpyridine) supported TiCl4 abbreviated as [P4-VP]-Ti(IV) as a new polymeric catalyst was easily prepared and characterized by using the X-ray spectroscopy, EDS, mapping, TGA/DTG and FTIR techniques. This catalyst was used for synthesis of imidazole derivatives via one-pot three-component condensation reaction of benzil, ammonium acetate and aldehydes. This protocol offers advantages such as short reaction time, simple reaction work-up with reusability of catalyst. Graphic abstract: [Figure not available: see fulltext.].
Magnetic horsetail plant ash (Fe3O4@HA): a novel, natural and highly efficient heterogeneous nanocatalyst for the green synthesis of 2,4,5-trisubstituted imidazoles
Hosseini Mohtasham, Nina,Gholizadeh, Mostafa
, p. 2507 - 2525 (2021/03/24)
Horsetail plant ash (HA), as a natural source of mesoporous silica, has been prepared from the exposure of horsetail plant (Equisetum Arvense) to high temperature. In the present study, a new magnetically separable and also recoverable Fe3O4 nanoparticles were synthesized in the presence of natural horsetail plant ash (HA) as a support to result in Fe3O4@HA. FT-IR, XRD, TEM, SEM–EDX and VSM analysis were combined to characterize the morphology and structure of this novel synthesized nanocatalyst. This magnetically solid acid nanocatalyst showed an excellent catalytic activity for the synthesis of 2,4,5-trisubstituted imidazoles at room temperature in aqueous media. The procedure led to corresponding products in high to excellent yields and appropriate times. Additionally, this nanocatalyst can be easily recovered by a magnetic field and reused for six other consecutive reaction runs without noticeable loss of its catalytic efficiency. Based on this study, Fe3O4@HA is found to be an efficient, magnetically separable, recyclable, and green catalyst with natural source. Graphic abstract: In this work, horsetail plant ash was used as a natural source of mesoporous silica for the synthesis of Fe3O4@HA as a highly powerful magnetically solid acid nanocatalyst, which was fully characterized using various techniques. The activity of the newly synthesized nanocatalyst was tested for the synthesis of 2,4,5-trisubstituted imidazole derivatives.[Figure not available: see fulltext.]
Fe3O4@THAM-Pd as a highly efficient magnetically recoverable nanocatalyst for facile one-pot assembly of substituted imidazoles under solvent-free conditions
Sanchooli Tazeh, Kazem,Heydari, Reza,Fatahpour, Maryam
, p. 1464 - 1472 (2021/09/18)
The current work has been explored an expeditious tactic toward one-pot multicomponent synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles using Fe3O4@THAM-Pd MNPs as an effective catalyst. With readily accessible benzil, ammonium acetate, anilines, and aromatic aldehydes as the simple starting materials, the condensation is run under solvent-free conditions to afford the target products in high yields. The other salient features of the present catalytic system are a simple work-up process, shorter reaction times, ease of preparation and handling of the catalyst, and cleaner reaction profiles. In addition, the sustainability of the methodology was checked by the investigation of the stability and reusability of the catalyst using an external magnet. The results showed that Fe3O4 @THAM-Pd MNPs can be reused for successive five runs without an appreciable decline in catalytic efficiency.
Magnetic nanoparticle-supported sulfonic acid as a green catalyst for the one-pot synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions
Amoozadeh, Ali,Kolvari, Eskandar,Sakhdari, Mahnaz
, p. 71 - 78 (2021/10/30)
In this work, magnetic nanoparticle-supported sulfonic acid (γ-Fe2O3-SO3H) is used as an efficient catalyst in the synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles in a short time (40-70 min for trisubstituted imidazoles and 30-40 min for tetrasubstituted imidazoles) and high-purity products were obtained (92-98% for trisubstituted imidazoles and 94-98% for tetrasubstituted imidazoles) in simple multicomponent reactions. The structure of these products was confirmed via FT-IR and NMR. Green and recyclable catalysts, eco-friendly and solvent-free conditions, high catalytic activity, shorter reaction time, easy recovery by an external magnet, high purity, and excellent yields are some features of these reactions.
TMSOTf-catalyzed synthesis of trisubstituted imidazoles using hexamethyldisilazane as a nitrogen source under neat and microwave irradiation conditions
Asressu, Kesatebrhan Haile,Chan, Chieh-Kai,Wang, Cheng-Chung
, p. 28061 - 28071 (2021/09/15)
In the process of drug discovery and development, an efficient and expedient synthetic method for imidazole-based small molecules from commercially available and cheap starting materials has great significance. Herein, we developed a TMSOTf-catalyzed synthesis of trisubstituted imidazoles through the reaction of 1,2-diketones and aldehydes using hexamethyldisilazane as a nitrogen source under microwave heating and solvent-free conditions. The chemical structures of representative trisubstituted imidazoles were confirmed using X-ray single-crystal diffraction analysis. This synthetic method has several advantages including the involvement of mild Lewis acid, being metal- and additive-free, wide substrate scope with good to excellent yields and short reaction time. Furthermore, we demonstrate the application of the methodology in the synthesis of biologically active imidazole-based drugs.
Evidence for the Formation of 1,2-Dioxetane as a High-Energy Intermediate and Possible Chemiexcitation Pathways in the Chemiluminescence of Lophine Peroxides
Boaro, Andreia,Reis, Roberta Albino,Silva, Carolina Santana,Melo, Diêgo Ulysses,Pinto, Alexander Garreta Gon?alves Costa,Bartoloni, Fernando Heering
, p. 6633 - 6647 (2021/05/29)
A kinetic study of the chemiluminescent (CL) reaction mechanism of lophine-derived hydroperoxides and silylperoxides induced by a base and fluoride, respectively, provided evidence for the formation of a 1,2-dioxetane as a high-energy intermediate (HEI) o
Catalytic conversion of 2,4,5-trisubstituted imidazole and 5-substituted 1H-tetrazole derivatives using a new series of half-sandwich (η6-p-cymene)Ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazone ligands
Vinoth, Govindasamy,Indira, Sekar,Bharathi, Madheswaran,Archana, Govindhasamy,Alves, Luis G.,Martins, Ana M.,Shanmuga Bharathi, Kuppannan
, (2020/11/16)
A new series of half-sandwich (η6-p-cymene) ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazide derivatives [Ru(η6-p-cymene)(Cl)(L)] [L = N'-(naphthalen-1-ylmethylene)thiophene-2-carbohydrazide (L1), N'-(anthracen-9-ylmethylene)thiophene-2-carbohydrazide (L2) and N'-(pyren-1-ylmethylene)thiophene-2-carbohydrazide (L3)] were synthesized. The ligand precursors and their Ru(II) complexes (1–3) were structurally characterized by spectral (IR, UV–Vis, NMR and mass spectrometry) and elemental analysis. The molecular structures of the ruthenium(II) complexes 1–3 were determined by single-crystal X-ray diffraction. All complexes were used as catalysts for the one-pot three-component syntheses of 2,4,5-trisubstitued imidazole and 5-substituted 1H-tetrazole derivatives. The catalytic studies optimized parameters as solvent, temperature and catalyst. The catalysts revealed very active for a broad range of aromatic aldehydes presenting either electron attractor or electron donor substituents and, although less active, moderate to high activities were observed for alkyl aldehydes.
