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1.
In this study, silica-coated Fe3O4 nanoparticle@silylpropyl triethylammonium polyoxometalate catalyst was fabricated and characterized using atomic absorption, inductively coupled plasma optical emission spectrometry, elemental analysis, thermogravimetric analysis, Fourier-transform infrared, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating sample magnetometry analyses. The activity of this catalyst was examined in the synthesis of tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones. The bonding of the polyoxometalate to the surface of the nanoparticles exhibited excellent catalytic activity in this synthesis. Besides, the catalyst showed good reusability and recovery from the reaction mixture. Tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones were synthesized in high yields in the presence of inexpensive supported solid acid catalysts under classical heating conditions. 相似文献
2.
Chlorophyll b was extracted from Heliotropium europaeum plant, then immobilized on magnetic nanoparticles (Fe3O4@SiO2@Chl-Mg) and found as an efficient and green catalyst for the preparation of a variety of benzimidazoles and spirooxindoles in mild conditions. The catalyst was fully characterized by Fourier-transform infrared (FTIR), ultraviolet–visible (UV–vis) spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric (TGA), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) analyses. To prove the catalytic influence of Mg over the reactions, the catalytic activity of the demetalated chlorophyll b as well as some other control experiments was investigated. High to excellent yields were achieved for all entries, whether benzimidazole or spirooxindole derivatives at short reaction times. The catalyst could be recovered and reused for several consecutive runs by a simple external magnetic field without any considerable reactivity loss. The properties of the recovered catalyst were investigated by various analyses. Finally, the reasonable mechanisms were proposed for the reactions based on the literature. 相似文献
3.
Two new coordination complexes based on benzimidazole dicarboxylic acid, Zn(Hbidc)?H2O ( 1 ) and Cd(Hbidc)(H2O) ( 2 ), have been synthesized under hydrothermal conditions. The complexes were characterized using elemental analysis, infrared and UV–visible spectroscopies, powder X‐ray diffraction, thermogravimetry and single‐crystal X‐ray diffraction. Structural analyses showed that the crystal structures of 1 and 2 are different, due to the various modes of linking of the benzimidazole dicarboxylic acid. Complex 1 has a two‐dimensional network structure and 2 has a three‐dimensional network structure. In addition, we studied the performance of the fluorescence response of two complexes. Results showed that the complexes can be used as chemical sensors for multifunctional testing, such as for UO22+, xanthine and Fe3+ ions. Even if the concentration is very low, they could also be detected, showing that coordination complexes 1 and 2 have very high fluorescence sensitivity. The detection limit for UO22+ is 5.42 nM ( 1 ) and 0.02 nM ( 2 ), that for xanthine is 1.37 nM ( 1 ) and 0.28 nM ( 2 ), and that for Fe3+ ions is 0.76 nM ( 1 ) and 0.62 nM ( 2 ). 相似文献
4.
Ramanjulu Abinaya Selvaraj Elavarasan B. Binish Dr. K. Mani Rahulan Prof. Dr. Kalpattu K. Balasubramanian Dr. Kamaraj Manokaran Dr. Elumalai Varathan Dr. Baburaj Baskar 《European journal of organic chemistry》2023,26(4):e202201098
Herein we report a simple and efficient oxidative coupling of various aryl methyl amines with diverse coupling partners, such as o-phenylenediamine (benzene-1,2-diamine), 2-aminobenzenethiol and 2-aminobenzamide, to synthesize the corresponding heterocycles using scalable and reusable heterogeneous catalysts under visible light irradiation. A systematic investigation led to the synthesis of benzimidazoles, benzothiazoles and quinazolinones under air atmosphere in very good to excellent yields. The strategy is atom economical and found to be tolerance towards different functional groups, and wide range of substrate scope. Furthermore, the methodology was demonstrated for its suitability on scale up and reusability. The density functional theory (DFT) calculations and the analysis of band structures of pristine and Ba doped CoMoO4 systems showed that the doping of Ba in place of Co improved the catalytic performance of the system. 相似文献
5.
A new carbazole functionalized Schiff base CBM was synthesized and characterized. CBM can selectively recognize Cu2+ via UV–vis and fluorescence signal among common biologically relevant metal ions. When Cu2+ was added to CBM, there was a significant enhancement at the maximum absorption wavelength of 393 nm and with a distinct blue shift. The maximum emission peak was significantly attenuated by a factor of about 15 times at 535 nm and the blue shift of emission wavelength was observed. When other metal ions were added, there was no remarkable change at the maximum absorption and emission peak. Under the illumination of 365 nm ultraviolet lamp, the color of the CBM solution changed from light blue to dark blue after the addition of Cu2+. The combination mechanism of CBM with Cu2+ was nicely explored by density functional theory studies. The probe CBM has good cell permeability, fluorescence electron microscopy experiments show that CBM can be used as a fluorescent probe to detect the presence or absence of Cu2+ in Hela cells. Furthermore, the probe CBM can also be used for the detection of copper ions in actual water samples. 相似文献
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《Journal of Coordination Chemistry》2012,65(3):171-180
Abstract 2-(2′-Pyridyl)benzimidazole (pybzim = LH) coordinates to iron(II) as a bidentate and forms the tris-ligated complex, [Fe(pybzim)3]2+ as isolated in the solid. Titration of [Fe(pybzim)3]2+ with base demonstrates the successive deprotonation of the imino hydrogens of the coordinated ligands. Protonation constants for the free ligand, pybzim (Iog10 K H = 11.33) and the complex, [Fe(pybzim)3]2+ (log10 K H 1 = 9.58, log10 K H 2 = 8.13 and log10 K H 3 = 6.97) were measured in 30% (v/v) H2O/EtOH. Results show that coordination to iron(II) increases the acidity of the imino hydrogen of the ligand. Spin-crossover behaviour of the complex were studied in different solvents ME, AC, AN, NM, NB, DMF, DMSO and ANL. The complex shows strong spin-crossover behaviour which is solvent dependent. Values of the spin-equilibrium constant (K sc) and the associated thermodynamic parameters (ΔH sc = 18.1–21.3 kJ mol?1 and δS sc = 69.6–84.4JK?1 mol?1) were calculated. An increase of the enthalpy is observed with increasing donor number (DN) of the solvent. 相似文献
9.
Xiaoye Ma Chuanqing Kang Wenhui Chen Rizhe Jin Haiquan Guo Xuepeng Qiu Lianxun Gao 《Journal of polymer science. Part A, Polymer chemistry》2016,54(4):570-581
To investigate the influence of hydrogen bonding on the properties of polyimides (PIs) containing rigid rod‐like groups, five symmetrical diamines containing benzimidazole, benzoxazole, and hydroxy group were synthesized, and then a series of PIs were prepared. Results showed that hydroxyl‐containing poly(benzoxazole imide)s possess higher glass transition temperature (Tg) and dimensional stabilities than their corresponding poly(benzoxazole imide)s. Moreover, the corresponding poly(benzimidazole imide)s presented the best performances, such as the highest Tg, the highest char yield and the highest dimensional stabilities. The influence of hydrogen bonding of benzimidazole on the properties of PIs was stronger than that of hydroxyl groups. Hydroxyl‐containing poly(benzoxazole imide)s were formed in crosslinking structures after heat treatment at 400 °C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 570–581 相似文献
10.
本文合成了2个新的三元铜(Ⅱ)配合物:[Cu(TBZ)(L-Met)(H2O)]ClO4.H2O(1)和[Cu(HPB)(L-Met)]ClO4(2)[TBZ=2-(4′-噻唑基)苯并咪唑,HPB=2-(2-吡啶)苯并咪唑,L-Met=L-蛋氨酸]。通过元素分析、摩尔电导率、IR、UV-Vis及电喷雾质谱对这些配合物进行了表征。用二倍稀释法研究了配合物的抗菌活性,发现配合物对金黄色葡萄球菌(Staphylococcus aureus,G+),枯草杆菌(Bacillussubtilis,G+),沙门氏杆菌(Salmonella,G-)和大肠杆菌(Escherichia coil,G-)具有良好的抑制作用。采用电子吸收光谱、荧光光谱、粘度测定及琼脂凝胶电泳方法研究了配合物与DNA的相互作用,结果表明,配合物以插入方式与DNA作用,在维生素C存在下通过羟自由基.OH,单线态氧1O2或者1O2类似物如Cu-O2,切割pBR322 DNA双螺旋结构。 相似文献