Papers by Keyword: Schiff-Base

Abstract: A Cd (II) complex with Schiff base ligand, 1-acetyl-2-naphthol-4, 4’-diaminodiphenylmethane (L), has been prepared. The photoluminescent properties of ligand and its Cd (II) complex have been investigated. The results show that the ligand and Cd (II) complex have stronger fluorescence in DMSO, however, their fluorescence are very weak in solid, in methanol and in ethanol, indicating that DMSO solvent could enhance the fluorescence of ligand and its Cd (II) complex. The Cd (II) complex is stable either in air or in organic solvents.

Abstract: (S,S)-N,N’- bi-(benzal)-1,2-cyclohexanediamine Schiff base (1) was synthesized and characterized by ¹ H NMR spectra, MS spectra and IR spectra. And the coordination reaction of 1 with chlorate of Ni(II) was studied. The reaction of 1 with Ni^II salt [NiCl₂] generates a new compound (2). 2 was characterized using IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. Crystal data for 2: space group Coca, with a = 24.580(4)Å, b = 9.5829(13)Å, c = 7.6836(11)Å, α=90.00º, β=90.00º, γ=90.00º, Z=4, V= 1809.8(5)ų, Dc=1.446 mg.m^-3, µ=1.376 mm^-1, F(000)=840. There are 6 coordination sites around Ni²⁺ of 2, which are respectively occupied by two oxygen atoms (all from two H₂O molecules) and four nitrogen atoms [all from two 1,2-cyclohexanediamine molecule]. The Ni atom and four chelating nitrogen atoms are coplanar. There exist intra-molecular H-bond and intermolecular H-bond. The mechanism of metal-assisted decomposition of 1 was also discussed briefly.

Abstract: Some 4-substituted-2-aminothiazoles were prepared starting from aromatic ketones and thiourea in the presence of powered iodine. Then treating 4-substituted-2-aminothiazole with substituted benzaldehyde gave corresponding 2-aminothiazole derives Schiff bases in good yield.

Abstract: A series of novel Schiff base containing diacetylferrocene and 5-alkyl-2-amino-1,3,4 -thiodizoles were reported in this paper. Diacetylferrocene(Ⅱ) was synthesised with ferrocene(Ⅰ) and acetyl chloride with AlCl3 as catalyst in CH2Cl2. In the presence of diacetylferrocene and 5-alkyl-2-amino-1,3,4-thiodizole reacted under solvent and catalyst condition to furnish Schiff base containing diacetylferrocene and 5-alkyl-2-amino-1,3,4-thiadiazoles(Ⅲ). Chemical structures have been confirmed by elemental annalysis and the spectral techniques of FTIR,1H NMR. Antimicrobial activity (in vitro) was evaluated against the two pathogenic bacterial strains. The compounds have shown better activity.

Abstract: Three bis-acetylferrocene schiff bases have been synthesized and characterized by IR, 1H NMR, and elemental analysis, the results conformed well with expected structures. The synthesized compounds were screened in vitro for their antimicrobial 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 these compounds are show excellent antimicrobia activities against Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi ,Bacillus subtilis,Staphylococcus aureus.

Abstract: In order to investigate the intermolecular hydrogen bonding of special amphiphiles, two bolaform amphiphilic Schiff bases (GN1 and GN2) with different hydrophilic spacers were designed, and their interaction with barbituric acid were tested by liquid chromatography. The chromatographic properties showed that both the Schiff bases showed hydrogen bonding interaction with barbituric acid. In addition, the influence of various detectors was also studied on both cases. Experimental results show that the test with FLD showed better determination than other detectors. It is proposed that due to the directionality and strong matching of hydrogen bond, one barbituric acid molecule can be encapsulated into the intramolecular area of GN1, while two barbituric acid molecules were trapped into the GN2 molecule through intermolecular H-bonds for GN2 due to the long spacer and flexible structure. A rational complex mode was proposed.

Abstract: Novel Schiff base-functionalized SBA-15 mesoporous silica is prepared, characterized and used as an adsorbent for heavy metal ion, Cu (II). The organic-inorganic hybrid mesoporous materials have been synthesized by two post-graftings of tetraethoxysilane (TEOS) with 3-aminopropyltrimethoxy-silane (APTES) and salicylaldehyde in sequence. The functionalized mesoporous materials are characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and nitrogen (N₂) adsorption-desorption analysis. The result indicates that, after sequent chemical modifications of aminopropyl and schiff base, the primary hexagonally ordered mesoporous structure of SBA-15 is not affected. The mesoporous silica, which has a BET surface area of 573.263 m² g^-1, a high pore diameter (centered at 5.24 nm) and pore volume of 0.847 cm3 g-1, exhibits the excellent adsorption capacity. The removal rate of Cu²⁺ in aqueous media is high and the adsorbent can be regenerated by EDTA and acid treatments without changing its properties.

Abstract: A series of metal complexes have been synthesized by the reaction of Schiff base with metal (II) salt solution. The complexes were characterized by UV and FT- IR studies. The study reveals that the geometry of the complexes were octahedral. The electronic spectra of these complexes show a strong absorption band in 550 – 580 nm region. This confirms the coordination of ligand with metal. The FT-IR shows a very strong band at 1606cm^-1 assigned to C=N stretching vibration. It is shifted to lower wave number because of the complex formation, suggesting that coordination of the Schiff base groups through N- atoms with the metal ion. The band at 3056cm^-1 is due to aromatic O-H stretching, the sharp peak at 750 cm^-1 and 688 cm^-1 are due to halogens substituted in the para position.

Abstract: A series of metal complexes have been synthesized by the reaction of Schiff base with metal (II) salt solution. The complexes were characterized by UV and FT- IR studies. The study reveals that the geometry of the complexes were octahedral. The electronic spectra of these complexes show a strong absorption band in 550 - 580nm region. This confirms the coordination of ligand with metal. The FT-IR shows a very strong band at 1616cm^-1 assigned to C=N stretching vibration. It is shifted to lower wave number because of the complex formation, suggesting that coordination of the Schiff base groups through N- atoms with the metal ion. The band at 3496 cm^-1 is due to aromatic N-H stretching, It is noted that a broad band of the asymmetric and symmetric O-H stretching mode around the region 3400 cm^-1 presumably due to H-O-H bending vibrations are not observed in the spectrum of complexes, which are indicating of the absence of the water molecule.