3230-38-4Relevant articles and documents
Effect of substituents on the UV spectra of supermolecular system: Silver nanoparticles with bi-aryl Schiff bases containing hydroxyl
Cao, Chao-Tun,Cheng, Shimao,Zhang, Jingyuan,Cao, Chenzhong
, (2018/11/25)
Effect of substituents on the ultraviolet (UV) spectra of supermolecular system involving silver nanoparticles (AgNPs) and Schiff bases was investigated. AgNPs and 49 samples of model compounds (MC), bi-aryl Schiff bases containing hydroxyl (XBAY, involving 4-OHArCH?NArY, 2-OHArCH?NArY, XArCH?NAr-4′-OH, and XArCH?NAr-2′-OH), were synthesized. The size of AgNPs was characterized by transmission electron microscopy (TEM), and the UV absorption spectra of AgNPs, XBAYs, and MC-AgNPs mixed solutions were measured, respectively. The results show that (1) the size of AgNPs is larger in MC-AgNPs solutions than that in AgNPs solution due to the distribution of MC molecules on the surface of AgNPs; (2) the UV absorption wavelength of XBAYs changes in the action of AgNPs and their wavelength shift exists limitation between XBAY and MC-AgNPs solutions; and (3) the wavelength shift limit of MC-AgNPs (λWSL) is influenced by the substituents X and Y and the position of hydroxyl OH. The wavenumber ΔνWSL of λWSL can be quantified by employing the excited-state substituent constant σexCC and Hammett constant σ of substituents X and Y. Comparing with the 4-OH, the 4′-OH makes the ΔνWSL a red shift, whereas the 2′-OH, comparing with the 2-OH, makes the ΔνWSL a blue shift.
Antioxidant activities and transition metal ion chelating studies of some hydroxyl Schiff base derivatives
Zhang, Ye,Zou, Biqun,Wang, Kai,Pan, Yingming,Liang, Hong,Yi, Xianghui,Wang, Hengshan
experimental part, p. 1341 - 1346 (2012/08/27)
Several hydroxyl Schiff base (HSB) compounds (1-10) with good radical scavenging activity (RSA) were designed. Compounds 6, 7, and 10 showed better RSAs than the common synthetic antioxidant 2,6-diterbutyl- 4-methylphenol (BHT) in DPPH and ABTS assays. To probe whether these HSB compounds may exert their antioxidant effect through transition metal ion chelation, the copper and ferrous chelating abilities of them were investigated. It was found by fluorescence quenching spectra that the binding constants Ka were in the range of 0.85×103-7.30×104 M-1. Further study was carried out by the complexation of a representative compound 5 with ferrous ion in mass spectrum. A 2:1 5-ferrous complex was readily formed in a methanol-water solution (v:v, 8:2), which confirmed that the chelation happened when the HSB compounds were treated with transition metal ions. The above results indicated that the transition metal ion chelation play an important role in their antioxidant abilities. Springer Science+Business Media, LLC 2011.
Microwave-assisted, solvent-free and parallel synthesis of some novel substituted imidazoles of biological interest
Sharma, Gyanendra Kumar,Pathak, Devender
experimental part, p. 375 - 380 (2011/02/25)
Solvent free microwave assisted synthesis of some novel substituted imidazoles of biological interest is reported. First, primary aromatic or heteryl amine was condensed with aryl or heteryl aldehydes to afford corresponding Schiff's base. The Schiff's base further on treatment with ammonium acetate (NH4OAC) and isatin using silica gel as the solid support, yielded the corresponding aryl imidazoles. In this paper a comparative study between the developed microwave method and conventional method is described. The synthesized compounds were analyzed by physical and analytical data. The synthesized compounds were evaluated for their antibacterial, anthelmintic, short-term anticancer and antitubercular activity. All the synthesized substituted imidazoles have shown good antibacterial activity against gram negative bacterial strains Klebsiella pneumoniae and Escherichia coli and moderate to good anthelmintic activity. The synthesized imidazole derivative possessed signifi-cant cytotoxic activity against Ehrlich's ascites carcinoma (EAC) cell lines. None of the compounds exhibited prominent antitubercular activity.
