Papers by Keyword: Schiff-Base

Abstract: A series of Ferrocene Schiff bases derived from glycine and their cobalt (II), copper (II), nickel (II), and zinc (II) metal complexes have been synthesized and characterized by IR, 1H NMR, MS and elemental analysis, the results conformed well with expected structures. The synthesized ligands, along with their metal (II) complexes, were screened in vitro for their antibacterial activity against three Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains. The results showed that the metal (II) complexes are more potent in antibacterial activity against one or more species in comparison with those of uncomplexed ligands.

Abstract: Some Schiff base compounds with aromatic substituted groups and their Cu-complexes have been designed and synthesized from the reaction of aromatic amines with salicylaldehyde. It has been found that depending on the molecular structures and substituted groups, the formed Schiff base compounds showed different properties, indicating distinct regulation of molecular design. UV and IR data confirmed commonly the formation of Schiff base and coordination with Cu(II) ions, as well as aromatic segment in molecular structures. In addition, the process of ex situ coordination seemed to change differently along with adding time, which could be ascribable to the presence of distinct substituted group and change of reaction activity. The spectral difference is mainly attributed to molecular structures, formation of Schiff base group and different substituted groups. The present results have showed that the special properties of Schiff base compounds could be turned by modifying molecular structures and substituted groups, which show potential application in fields of functional material fields such as liquid crystal and catalysts.

Abstract: Two Schiff bases of chitosan (CTS) were synthesized from 4-methoxylbenzylaldehyde (CH₃O-CTS) and 4-methylbenzylaldehyde(CH₃-CTS). The Schiff bases were characterized by FTIR, DSC-TGA, solid ¹³C CP-Mas NMR, and elemental analysis. Antibacterial activities of the Schiff bases against Escherichia coli and Staphylococcus aureus were measured by the optical density method. The antibacterial activity of the Schiff bases is better than that of the original CTS. The IC₅₀ of CH₃O-CTS and CH₃-CTS against Escherichia coli is respectively 40.3 ppm and 43 ppm, which being 38.5 ppm and 39.5 ppm against Staphylococcus aureus, lower than IC₅₀ of chitosan, being 59.5 ppm and 52 ppm against Escherichia coli and Staphylococcus aureus, respectively.

Abstract: A series of novel copolymers poly (AOBDA-co-DNMMA)s containing 2-Allyloxy-N-benzyl- idene dodecylamine (AOBDA) and 1.4-dioxaspiro[4.4] nonane-2-methyl methacrylate (DNMMA) were synthesized. The copolymers could form stable condensed monolayer at air/water interface and be transformed onto solid substrates successively. Positive-tone patterns with the resolution of 0.75 μm of the copolymers Langmuir-Blodgett (LB) films with 40 layers were obtained by deep UV irradiation, followed by developing in acetone. The etched gold patterns with resolution of 0.75 μm were also obtained, showing that the copolymer has enough resistance to wet etching suitable for fabricating photomask. The mechanism of photolysis was also investigated by UV, IR and GPC.

Abstract: The title complex, [(C₅H₅N)Ni(C₁₅H₁₁N₂O₂Br)], was synthesized by the reaction of the 5-bromo-2-hydroxyphenyl ethyl ketone benzoyl hydrazone, pyridine ligand and nickel chloride in acetone. The crystal structure was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a = 29.507(4) Ǻ, b = 7.7738(11) Ǻ, c = 20.205(3) Ǻ, β = 126.614(2)º, Z = 8, V = 3720.1(9) Ǻ³. Its crystal structure was determined and refined to a final R= 0.0304 for 8902 independent reflections. The center nickel atom is four-coordinated. The antibacterial activity of the ligand and its complex was also studied.The antibacterial experiments indicate that they have antibacterial activity to P.aeruginosa, S.aureus, E.coli and the complex has higher activity than the ligand.

Abstract: In this study, 1-phenyl-3-(1-aniline)-1-propene (PAP) was synthesized by aniline and Cinnamaldehyde, and its inhibitive effect on N80 steel in 15% HCl solution was investigated by using weight loss and electrochemical techniques (such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization). The chemical structure of PAP was confirmed by Fourier transform infrared spectroscopy (FTIR). The results were shown that, the inhibition efficiency of PAP could exceed 99%. Polarization measurements indicated that, the inhibitor acted as mixed type.

Abstract: In this paper, a new kind of chitosan schiff base and its zinc complexes were prepared. Chitosan schiff base (CS-DBSB) was obtained when 3, 5-Di-tert-butyl salicylaldehyde was introduced to the C-2 nitrogen position of chitosan. Its zinc complex of CS-DBSB (CS-DBSB-Zn) was also prepared. The structure and performance of physicochemical characteristics of CS-DBSB and CS-DBSB-Zn were examined by FT-IR, elemental analysis, thermogravimetric (TG). The thermal behaviors of CS-DBSB and CS-DBSB-Zn were described. TG curves presented three events including water loss, decomposition of the polysaccharide generating a carbonaceous residue that burns at higher temperatures.

Abstract: Some novel L-glutamate-based Schiff base compounds with glutamate segment and different substituted groups have been designed and synthesized from the reaction of aromatic L-glutamate amine with different aldehydes. It has been found that depending on the molecular structures and substituted groups, the formed Schiff base compounds showed different properties, indicating distinct regulation of molecular design. UV and IR data confirmed commonly the formation of Schiff base as well as aromatic substituted groups in molecular structures. Thermal analysis also clarified the structural influence of these compounds in different temperature ranges. The difference of thermal stability is mainly attributed to molecular structures, formation of Schiff base group and different substituted groups. These results indicated that the the special properties of Schiff base compounds could be regulated through the design of molecular structures and substituted groups, which leads to potential application in fields of functional material as well as catalyst.

Abstract: Two aromatic Schiff base derivatives and the corresponding metal complexes with different substituted groups were synthesized and characterized by many methods. The products were characterized by UV-Vis spectra, FT-IR spectra and thermal analysis, while the thermal stability was measured by TG-DTA instrument. FT-IR analysis indicated that the nitrogen atom in imino group and oxygen atom in phenolic hydroxyl group participated in coordinating with transition metal ion in different bridged mode. UV spectra also verified that different coordination modes can be performed between metal ions and ligands. In addition, the thermal stability of metal complexes had been obviously superior to that of the ligands. All results give a useful clue to obtain Schiff base derivatives with versatile property by regulating intramolecular substituted group and species of metal ion. The present results have showed potential application in fields of functional material and catalyst.

Abstract: A novel glycine-based Schiff base derivative (abbreviated as C16GlySb) containing long alkyl chain was synthesized from glycine reacted with 4-cetyloxy-2-hydroxybenzaldehyde and sequentially coordinated with various metal ions to give the corresponding metal complexes (abbreviated as G-M). The products were characterized by UV-Vis spectra and FT-IR spectra. At the same time, the thermal stability was measured by TG-DTA instrument. FT-IR analysis indicated that the nitrogen atom in imino group, oxygen atom in phenolic hydroxyl group, and carboxylic ion participated in coordinating with transition metal ion in doubly-bridged mode. UV spectra showed that compared with ethanol solution, the cast film on quartz plate showed H-type or J-type aggregate structure. In addition, the thermal stability of G-M had been obviously superior to that of the ligand C16GlySb. The present results have showed potential application in fields of functional material and catalyst.