Applied Chemistry

The novel ligand complexes of Cu(II),Fe(II),Co(II) and Bi(V) with biological active streptomycin and oxime were prepared and characterized by spectral techniques. The cell parameters was determined by X-ray powder pattern and the molecular models represents a better understanding of the arrangement of the atoms in the molecules in three dimensions.

The title compound has been prepared in high yield from 9-benzyl-purine derivative by reaction with diethoxymethyl acetate (DEMA). The structure of the tricyclic compound, 7-(2-chlorobenzyl-3H-[1,2,4]triazolo[3,1-i]purine 2, was confirmed by X-ray analysis. Semiempirical calculations for predicting geometrical parameters are in excellent agreement with the X-ray crystal structure.

Mn(II), Co(II), Ni(II), Cu(II) and Pd(II) complexes of the Schiff base, 6-methyl-3-[[4-(methylsulfanyl)phenyl]imino}methyl]-3,4-dihydro-2H-chromen-4-ol are synthesized and characterized by microanalysis, conductance, 1H NMR, infrared and electronic spectral measurements. The ligand coordinates through the chromenol O and imine N atoms to the metal ions, and the Co(II) and Ni(II) complexes are in the trans-isomeric form as shown by IR measurements. All the complexes form as [ML2]xH2O with the exception of the Mn(II) complex which analyzed as [MLNO3]H2O. Electronic measurements are indicative of a four coordinate, tetrahedral /square-planar geometry for the complexes and none is an electrolyte in nitromethane. The antibacterial studies reveal that the Schiff base and its Cu(II) complex exhibit broad-spectrum antibacterial activity against Proteus mirabilis, Escherichia coli and Staphylococcus aureus with inhibitory zones range of 11.0-13.0 mm and 10.0-16.0 mm respectively. The cytotoxic study shows that the Cu(II) complex has the best in-vitro anticancer activity against both HT-29 (colon carcinoma) and MCF-7(human breast adenocarcinoma) cells with activities of about a half (17.02 ?M), and a fifth(9.78 ?M ) that of Cis-platin respectively.

A copper (II) complex, [cu(phen)(L-Ala)U](ClO4) (phen=1,10- phenanthroline, L-Ala =L-alanine,U =urea ), has been synthesized and characterized by Infra-red, EPR spectral and elemental analysis methods. The interaction with calf-thymus DNA has been studied by means of electronic absorption spectroscopy, emission spectroscopy, viscosity and cyclic voltammetry has been conducted to assess their interaction between their complex and DNA. A sample of copper II complex was tested for its Antimicrobial Activities and it was found to have good antimicrobial activities.

Studies on synthesis, characterization, antimicrobial and antioxidant properties of some metal(II) complexes of the mixed ligands, Vitamins B2 (Riboflavin, HL) and Benzoic acid (HL2), where M = Mn, Fe, Co, Ni, Cu and Zn were carried out. The conductivity measurements and percentage metal analysis confirmed that the metal complexes were covalent in DMS with the formulations [M(HL)(HL1)Cl2] and [M(HL)(HL1)SO4]. The room temperature magnetic moments and electronic spectra measurements were corroborative of 6-coordinate, octahedral geometry for all the metal complexes. In addition, the Fe(II), Co(II) and Ni(II) complexes exhibited spin-crossover, the Mn(II) and Cu(II) complexes were dimeric and the Zn(II) complex was mononuclear. The infrared spectra data showed that the coordination in the metal complexes occurred through the hydroxy oxygen atoms in Riboflavin, and the carboxylate oxygen atoms in Benzoic acid. The antimicrobial screening of the metal complexes against Escherichia coli, Proteus spp, Streptococcus pyogenes, Candida albicans, Salmonella sp, Streptococcus sp, Bacillus spp, Staphylococcus sp and Pseudomonas spp revealed that the Co(II) complex had the best activity with inhibitory zones range of 7.0-20.0 mm. The antioxidant screening of the metal complexes showed that [Cu(HL)(HL2)Cl2] had the best activity with percentage inhibition of about 50.0 which was about twice that of the standards, Ascorbic acid and ?-tocopherol, proving its potentials as an anticancer agent.

The mixed-ligand complexes, [Cu(bipy)2 (4-methylimidazole-5-carboxaldehyde)(ClO4)2 1 and Cu(bipy)2(indole-3-carboxaldehyde)](ClO4)2 2 were synthesized and characterized by employing elemental analyses, metal analyses, infrared and UV-Vis spectroscopy, room temperature magnetic susceptibility measurements, conductivity measurements and theoretical studies. The elemental and metal analyses show good agreement which support the formulation for the prepared complexes while the infrared spectroscopy revealed the coordination through both the nitrogen atom of the imidazole ring and the oxygen atom of the aldehyde group for 1. In complex 2, the coordination was through the oxygen atom only. The electronic transitions observed in the UV-Vis region show the various intraligand transitions and the d-d transitions at 14,347cm-1 with a shoulder at 11,115 cm-1 for 1 and for 2 the bands are 13,642 cm-1 and 11,494 cm-1. The magnetic moments 1.44B.M (1) and 1.34B.M (2) show antiferromagnetic properties of the complexes. From the theoretical studies, the Binding energies (Stabilization Energies) are found to be -33.85 (-466.46) kcal/mol and -32.73 ( -465.17) kcal/mol for 1 and 2 respectively. Therefore, the theoretical calculations corroborated the formation of a six –coordinate complex in 1 and a five –coordinate geometry around the Cu ion in 2. The conductivity measurement revealed that the complexes are 1:2 electrolytes.

1-[2’-Chloro-5’-Sulphophenyl]-3-Methyl-4-Azo–[2”-Carboxy-5”-Sulphonic acid]-5-Pyrazolone was prepared by diazotization of 4-sulphoanthranilic acid and then coupling with 1-[2’-Chloro-5’-Sulphophenyl]-3-Methyl-5-Pyrazolone in alkaline medium. It was characterized by elemental analysis and spectral studies. The transition metal chelates of the same were prepared with Cu2+, Ni2+ , Co2+ , Mn2+ and Fe3+ and characterized by IR spectral studies and physico chemical studies. The antimicrobial activity of ligand and its metal chelates were screened against various gram-positive (+) and gram-negative (?) organism. The results show that all these samples are more or less active agents against various organisms.

The metal complexes of Co²⁺ and Ni²⁺ 1,2,3-triazole mixed ligand have been synthesized. The synthesized complexes in different ratios have been characterized by element chemical analysis, molar conductance and Uv-visible and FTIR spectroscopic studies. IR spectra data suggests the involvement of sulphur and nitrogen in coordination to the central metal ions. On the basis of spectral studies and elemental analysis, a tetrahedral geometry was assigned for the nickel complexes while dimerization was suspected for cobalt(II) complexes. The free ligand and metal complexes were tested in vitro against a number of microorganisms (fungi and bacteria) in order to assess their microbial properties. They are found to be proactive against fungi and bacteria upon the metal complexes, nickel complexes performed better than the cobalt complees.

Hydrazone compounds derived from 2–Amino –5–chlorobenzophenone. The structures of the compounds are purified and characterized by means of TLC, melting point, IR, 1H NMR spectral data. The antimicrobial activity against bacteria and fungi was studied. The result of preliminary biological tests showed that of these compounds possess biological activaties.

Some metal(II) complexes of mixed ligands-dimethydithiocarbamic and p-aminobenzoic acids were synthesized (M = Mn, Fe, Co, Ni, Cu and Zn) and characterized by solubility, percentage metal, conductivity, infrared and electronic spectra measurements. Infrared data showed that the dimethydithiocarbamic and p-aminobenzoic acids coordinated through the sulphur atoms, and the carboxylate oxygen atoms to the metal atoms respectively. Electronic spectra and room temperature magnetic moments corroborated equilibrium between high spin and low spin octahedral geometry (spin-crossover) for the Mn(II), Fe(II), Ni(II) and Co(II) complexes, while the Cu(II) and Zn(II) complexes were octahedral and mononuclear. The antimicrobial activities of the metal complexes against Escherichia spp, Streptococcus spp, Proteus sp, Candida sp, Salmonella sp, Bacillus spp, Staphylococcus sp and Pseudomonas spp showed that the Mn(II), Fe(II) and Zn(II) complexes had very good antimicrobial activities against these microbes with inhibitory zones range of 7.0-20.0, 7.0-20.0 and 9.0-27.0 mm respectively, just like Streptomycin (7.0-29.0 mm) proving their potentials as broad-spectrum antimicrobial agents in-vitro.