Applied Chemistry

Nickel (II) mixed chelates of Schiff base derived from salicylaldehyde and aniline with various dithiocarbamate ligands have been characterized by metal analysis, microbial activity, solubility, infrared and electronic spectral measurements. The compounds were generally insoluble in water and soluble in some solvents. The metal analysis gave values close to the expected percentage metal values confirming the coordination of the nickel metal in the complexes. The interpretation of the infrared spectra of the complexes showed that the two uninegative ligands coordinate to the metal ions in their complexes in a bidentate mode, the dithiocarbamate ligands binding through both sulphur atom and the Schiff base through the azomethine nitrogen and phenolic oxygen. The electronic spectra revealed that the nickel complexes are typical of square planar as evidenced by the presence of two d-d absorption bands. The synthesized compounds showed moderate to high antibacterial activity against the test bacteria and can be effective as antibiotics.

A copper complex of the type [Cu(Bipy)(L-Tyr)(TU)](ClO4), where Bipy = 2,2’ Bipyridine, Tyr = L-Tyrosine and TU = Thiourea, was synthesised and characterised by elemental analysis, UV-Visible, IR, conductivity measurement and EPR studies. DNA-binding properties have been studied by electronic absorption, emission, viscosity and cyclic voltammetric methods. The results suggest that the copper(II) complex bind to DNA via different modes. Gel electrophoresis study reveals the fact that the copper(II) complex cleaves super coiled pBR 322 DNA to nicked and slight linear forms in the presence and absence of ascorbic acid. The in vitro antimicrobial study indicates that the complex has good activity against gram positive, gram negative bacteria and fungus.

The interaction of transition metal complexes with DNA has long been a subject of intensive investigation with the perspective of development of newer materials for application in biotechnology and medicine. These investigations have resulted in the synthesis of many new metal complexes, which bind to DNA by non-covalent interactions such as electrostatic binding, groove binding and intercalative binding [1,2]. Hence, the current growing interest in small molecules that are capable of binding and cleaving DNA is related to their utility in the design and development of synthetic restriction enzymes, new drugs, DNA foot-printing agents, etc., and also to their ability to probe the structure of DNA itself [3].

A copper complex of the type [Cu(Phen)(L-Tyr)(TSC)](ClO4), where Phen = 1,10 Phenanthroline, Tyr = Tyrosine and TSC = Thiosemicarbazide, was synthesised and characterised by elemental analysis, IR, conductivity measurement and EPR studies. DNA-binding properties have been studied by electronic absorption, emission, viscosity and cyclic voltametric methods. The results suggest that the copper(II) complex bind to DNA via different modes. Gel electrophoresis study reveals the fact that the copper complex cleaves super coiled pBR 322 DNA to nicked and linear forms in the presence and absence of ascorbic acid. The in vitro antimicrobial study indicates that the complex has good activity against gram positive, gram negative bacteria and fungus.

The Schiff base, 3-(-1-(2-pyrimidinylimino)methyl-2-napthol with NO chromophores have been synthesised and its Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes isolated. The ligand coordinates to the metal ions in the ratio 2L: 1M, through the azomethine N and napthol O atoms, resulting in N2O2 chromophores around the central metal atom. The % metal, infrared (IR) and electronic spectral measurements are consistent with the adoption of a 4-coordinate square planar/ tetrahedral geometry for the metal complexes. The infrared spectra show lone vC=N, vM-N and vM-O bands for the metal complexes in the range 1649-1655 cm-1, 579-599 cm-1 and 410-497 cm-1 respectively, indicative of the existence of geometric isomerism, and the complexes are in the cis-isomeric forms. Further evidence of coordination is the higher melting points of the complexes in the range 237-301oC in comparison with that of the ligand at 92-94oC. The in-vitro antibacterial studies show that the Schiff base and its Zn(II) complex exhibit broad-spectrum antibacterial activities against Bacillus cereus, Pseudomonas aeruginosa, Klebsiella oxytoca, Staphylococcus aureus and Proteus mirabilis like ciprofloxacin (30.0-50.5 mm) with inhibitory zones range of 14.0-20.0 and 12.0-17.5 mm respectively in the same assay.

A Schiff base ligand derived from salicylaldehyde and 2-aminophenol and its complex of Co(II) were synthesized. The ligand and the complex were characterized by elemental analysis, conductivity measurement, FT-IR and melting point or decomposition temperature measurements. The elemental analysis data show the formation of 1:1 metal to ligand ratio. The experimental data show that the ligand act as a tridentate ligand (ONO). The Schiff base and the complex were screened for antibacterial and antifungal activity. The complex shows higher activity than the free ligand.

Chalcone derivatives were synthesized by reaction of some benzaldehyde derivatives with acetophenone , then the products obtained were allowed to react with urea, thiourea and hydroxylamine, to give the heterocyclic derivatives of oxazine, thiazine and isoxazole respectively. The final products have been characterized by elemental analysis, IR and proton NMR spectra. These compounds were also screened for their antibacterial activities.

As a result of one-pot three-component reaction of ketoaziridines with two aromatic aldehydes in presence of ammonium acetate 1,3-diazabicylo[3.1.0]hex-3-ene derivatives were achieved. These compounds exhibit good photochromic behavior in solution and crystalline phase. The photochromic behavior of compounds 4(a-e) was investigated using absorption spectral changes.

Copper (II) phthalocyanine and 2, 9, 16, 23 tetrakis nitro copper (II) phthalocyanine  has been synthesized respectively from phthalonitrile and 4-nitro phthalonitrile under solvent-free condition using two different catalysts. 4-Nitro phthalonitrile synthesized from phthalimide in three steps. The reaction time of ruthenium chloride and HZSM-5 catalysts was very shorter than ammonium molybdate and H? catalysts. The yield while we used ruthenium chloride and HZSM-5 catalysts were very higher than another. The newly prepared compound has been characterized by IR, UV-Vis, ¹HNMR and XRD spectra.

Drugs normally synthesized to use as medication to treat diseases like cancer and microbial infections, these synthesized drugs were interested more than naturally-derived drugs which have been shows low activity or not as efficient against diseases. A new ligand 3-methylbenzyl (2Z)-2-[1-(pyridin-4-yl)ethylidene]hydrazine carbodithioate (PE3MBC) and its Cd(II), Cu(II), Co(II) and Zn(II) metal complexes. The new ligand and metal complexes were characterized via various physico-chemical and spectroscopic techniques. Cd(II) complex show more activity against microbes and against cancer cell line MCF-7, while other complexes does not shows activity like cadmium complex, all the complexes does not shows any activity against MDAMB-231 cell line. The fatal of the cancer and the microbes cell was due to inhibition of DNA synthesis which was probably due to chelating with metals complexes, or could be referred to lipophilicity, presence of hydrophobic moiety in the complex molecule, also could be due to steric effects and electronic effects.