>Magister Scientiae - MSc / In this thesis we describe the synthesis of several carbonyl complexes of molybdenum and tungsten, compounds (Cl-ClO). The compounds Cl- C4 are zero valent carbonyl complexes containing N-base ligands prepared by following a common synthetic procedure. Compounds Cl and C2 were metal pentacarbonyl of 3-(1-methylpyrrolidin-2-yl) pyridine while C3 and C4 are metal tetracarbonyl complexes of 3, 5- dimethylpyrazole, (M=Mo, W). The compounds C5-C10 are divalent metal carbonyl complexes. Compounds CS and C6 were 3,5-dimethylpyrazole dibromotricarbonyl metal complexes prepared from the dibromotetracarbonyl metal dimers at room temperature while the compounds C7 and C8 were cyclopentadienyl halogenoaryltricarbonyl complexes prepared from the cyclopentadienyl metal dimers. Compounds C9 and ClO were prepared from cyclopentadienyl metal dimers by reacting the [CpM(C0)3r anion with CCl4 to obtain [CpM(C0)3Cl] and further reacted with 3-(1- methylpyrrolidin-2-yl) pyridine. All the compounds, Cl-ClO, were characterized by the standard analytical techniques such as FTIR, 1H, 13C NMR; and UV-Vis spectroscopy. Compound C4 was characterized by X-ray crystallography. The structure is depicted as having a distorted octahedral geometry around the metal centre. The compounds Cl-ClO were then tested towards the epoxidation of selected cyclic and straight chain alkenes. The substrates used were cis-cyclooctene (Cyg), 1-octene (C8) cyclohexene (Cy6), 1-hexene (C6) and styrene (Sty). The epoxidation reactions were carried out at a temperature of 55 °C using tertbutylhydroperoxide (TBHP) as the oxidant and dichloroethane (DCE) as the solvent. The metal carbonyl complexes were pre-activated by first reacting them with the oxidant TBHP to obtain the metal-oxo complexes which are the active compounds for epoxidation reactions. The products were analyzed using GC techniques. The compounds, Cl-ClO showed a promising activity towards epoxidation reactions owing to the high conversions obtained by these compounds. For example, conversions of 81% (1-octene), 90% (cis-cyclooctene) were obtained by compound C5, 87% (cis-cyclooctene-compound C3, 95% (cis-cyclooctene-compound · C7) and 69% (ciscyclooctene- compound C4) for an average period of 24 h. The divalent metal carbonyl complexes showed a higher activity but with poor selectivity towards the expected epoxides compared to the zero valent metal carbonyl complexes.

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<p style="text-align: justify; ">Reactions of 3,5-dimethylpyrazole-1-carboxamidinium&nbsp;nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural&nbsp;analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, too.</p> / <p> Reactions of 3,5-dimethylpyrazole-1-carboxamidinium&nbsp;nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural<br /> analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, too</p>