Organic Chemistry

In this research we synthesized yellow colored salen ligand from the condensation reaction of ethylenediamine and salicylaldehyde in absolute ethanol. After this, we synthesized salen and thiocyanate bridging ligand complexes of transition metals including Co(II), Fe(III), Cu(II) and Mn(II). Synthesized compounds were characterized with application of IR, Uv/Vis spectroscopy and cyclic voltammetry and conductivity. Presence of a sharp pick near to 2000cm^-1 supports coordination of thiocyanate ligand to metal center. Shifts in Ir spectra of complexes compared with free ligand refres to coordination on salen ligand to metals via O and N dentates. As a result of ligand coordination to metals, shifts and absorption magnitude in UV/Vis spectra of complexes in the comparison with ligand can be observed. Conductivity measurements revealed that some complexes are ionic compounds. CV characterizations showed that the compounds have reversible and irreversible behaviors.

Various ethyl-2-(2- substituted phenyl hydrazono)-3-oxobutyrate (2a-h) condensation with isonicotinyl hydrazide (i.e. isoniazide) (3) to 1-isonicotinoyl-3-methyl-4-(2-substituted phenylhydrazono)-1H-pyrazol-5(4H)-one (4a-h). The structures of all these compounds (4a-h) were recognized on basis of analytical and spectral data. The newly synthesized compounds were evaluated for their antimicrobial activity against various bacteria and fungi.

Pulverized fruits (500g) of Lantana camara on hydrodistillation, afforded oil in the yield of 0.4% (v/w). Analysis of the oil using GC and GC-MS showed that the bulk of the oil is characterized by the abundance of sesquiterpenoids (91.9%). The percentage composition of monoterpenoids in the oil was 7.1%, while phenylpropernoids were detected in trace amounts. The principal constituents of the oil were; germacrene D (38.1%), germacrene-D-4-ol (19.6%), ?-caryophyllene (17.7%) and germacrene B (16.5%). The abundance of germacrene D in the oil shows that the oil is of germacrene D chemotype.

The adsorption characteristics of Georgian natural and acid-modified forms of clinoptilolite and laumontite have been studied in order to determine possibilities of their application in treatment of water contaminated by metals. It was found that natural clinoptilolite washed by diluted acid is the most effective adsorbent for barium, cobalt and lithium, while strontium, manganese, nickel and lead can be captured by modified clinoptilolite, but zinc, iron and copper – by modified laumontite. A combined filter (quartz sand + washed clinoptilolite + laumontite + clinoptilolite, both treated with 1.0N HCl solution) is offered.

The fungus X. badia was cultured on 3% aqueous malt enriched with 6% glucose in ten Thompson bottles for eight weeks. Solvent extraction with ethyl acetate and subsequent drying on a rotary evaporator, afforded a dark brown gummy solid (5.0 g). TLC studies indicated that the crude extract was a mixture of four components. The dark brown gum was chromatographed over silica gel in a column of size 80 cm x 2.5 cm. The column was eluted with toluene, ethyl acetate and acetic acid (50:49:1) and the eluent collected in volumes of 3.0 ml. Fraction 3 gave a yellowish oil (150 mg). The oil was triturated with n-hexane to give a white powdery solid (12 mg). The solid was recrystallized from the same solvent system, yielding white crystals (8 mg). Spectroscopic analysis of this compound indicated that it is R- mellein. This is the first report of this secondary metabolite from Xylaria badia.

This work aims to evaluate the effects of current density and plating time on the corrosion resistance of ZnNiSiO2 electroplated coating. For the plating time, the results showed that coating thickness increased with increasing the plating time. The average thickness was 6, 15 and 25 µm, when used plating time of 10, 30 and 50 minutes, respectively.Whereas, when the current density values varied from 1 A/dm2 to 5 A/dm2, the coating thickness was in range of 14.7 - 15.3 µm, with the same plating times. After 900 hours of exposure to salt spray, the surface appearance of coatings indicated that the plating time of 30 minutes provided the highest corrosion resistance. These data were coherent with the findings from polarization curve measurement.

Mangrove plants and their associated micro fauna have been a rich source of bioactive secondary metabolites, though only limited antimicrobial screening of this chemo-diversity source has been reported. In this study, unidentified endophytic fungi BBMS and BBMAV were isolate from the bark of black mangroves obtained from the coastal forest of Ayensu estuary. The endophytes were cultured in static medium made of 3%(w/v) malt concentrate and 6%(w/v) glucose in distilled water. The fungi were cultured for 8 weeks and harvested. Ethyl acetate extraction of the filtrate followed by drying on a rotary evaporator afforded 1.20 g and 1.05 g of BBMS and BBMAS respectively. TLC studies and GC-MS analysis indicated that the extracts contained interesting secondary metabolites. A bioassay of the extracts was carried out on human pathogen and cocoa infesting microbes. The bioassay results indicated that the extracts were active against all the test organisms. ABTS and DDPH free radicals scavenging activities were also tested with the extracts. The results indicate that the extracts of the fungal isolates exhibited high potency of antioxidant activity.

Cytochalasin D is a cytotoxic compound used in cellular research and drug development. Cytochalasin D is produced from molds, often in mixtures which are difficult to purify. Yields from the synthesis of the compound are poor, hence the high cost of the cytotoxic compound. Static cultures of a group of endophytic fungi: were sub-cultured in 250 ml conical flask each for three weeks. Each of the endophyte culture was transferred into ten 2.0 dm3 Thompson bottles and allowed to grow for 8 weeks. TLC studies of the individual crude extracts indicated that the four mangrove endophytes produced the same compounds. The crude extract obtained from RAR 5-6 was dissolved in warm ethyl acetate and left overnight. A white solid (0.90 g) precipitated from the solution. The solid was removed by filtration and recrystallized from the same solvent to give pure cytochalasin D. The resulting filtrate was chromatographed on silica gel. Fraction 5 yielded a yellow viscous liquid (270 mg). This was triturated with alcohol and left to stand for 48 h to give white crystals, Spectroscopic analysis indicated that the compound was 5-carboxymellein. The production of pure cytochalasin D from these endophytic fungi could be a source of commercial production of this important cytotoxic compound.

In this research, phytochemical screening and antibacterial properties of Phyllanthus muellerianus were investigated to confirm the potency of the plant on the basis of ethno medicinal significance. The percentage yield of crude methanolic leave extract of Phyllanthus muellerianus was 12.58% while the phytochemical screening of crude methanolic leave extract of Phyllanthus muellerianus revealed the presence of anthraquinone, carbohydrates, tannins, alkaloids, flavonoids, cardiac glycosides, saponin and lipids. The result of the antibacterial activities showed that the crude methanolic leave extract of the plant exhibits high potency against all the tested organisms. These properties above may be the reason Phyllanthus muellerianus plant has been reported to be useful in the treatment of several ailments.

The FT-Raman and FT-Infrared spectra of Guaiacol have been recorded in the regions 3500?100 cm?1 and 4000?500 cm?1 respectively. The observed frequencies were assigned to various modes of vibrations on the basis of normal coordinate calculations, assuming C1 point group symmetry. The assignment of fundamental vibrations agrees well with the calculated frequencies. Second order perturbation energies and electron density (ED) transfer from filled lone pairs of Lewis base to unfilled Lewis acid sites of Guaiacol are discussed on the basis of NBO analysis. The theoretically calculated harmonic frequencies are scaled by common scale factor. The observed and the calculated frequencies are found to be in good agreement. The thermodynamic functions were obtained for the range of temperature 100–1000 K. The polarizability, first hyperpolarizability, anisotropy polarizability invariant has been computed using quantum chemical calculations. The chemical parameters were calculated from the HOMO and LUMO values. The NMR chemical shielding anisotropy (CSA) parameters were also computed for the title molecule.