Naslov
Synthesis and properties of molybdenum complexes with pyridoxal derivatives

Autori
Pisk, Jana

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, doktorska disertacija

Fakultet
Prirodoslovno-matematički fakultet

Mjesto
Zagreb

Datum
12.07

Godina
2012

Stranica
194

Mentor
Vrdoljak, Višnja

Ključne riječi
molybdenum(VI) and (V) complexes ; pyridoxal ; thiosemicarbazones ; hydrazones ; diamines ; OAT ; solvent free epoxidation ; cyclooctene

Sažetak
The work presented herein relates the coordination chemistry of molybdenum(VI) and (V) complexes with pyridoxal based ligands. Coordination abilities of pyridoxal- thiosemicarbazones, hydrazones and Schiff bases obtained from diamines were investigated. Forty novel molybdenum complexes had been prepared and fully characterised. The reactions of [MoO2(acac)2] and tridentate pyridoxal derivates, in methanol, afforded mononuclear molybdenum(VI) complexes [MoO2(L)(MeOH)] or [MoO2(HL)(MeOH)]Cl, while the same reaction in acetonitrile resulted with polynuclear molybdenum(VI) complexes [MoO2(L)]n or [{; ; ; MoO2(HL)}; ; ; Cl]n. Varying ratio of the ligand towards [MoO2(acac)2] created new salts of the formula [{; ; ; MoO2(HL)}; ; ; 2]Mo6O19 or [MoO2(HL)(MeCN)]2Mo6O19 composed of hexamolybdate oxo-clusters and cationic molybdenum(VI) complex. In addition, molybdenum(VI) complexes with ONNO ligands were obtained offering different type of coordination to the molybdenum atom – tetradentate [MoO2(L)] or didentate [{; ; ; MoO2(MeOH)2}; ; ; 2L]. The reactions of molybdenum(V) starting compounds and pyridoxal derivates resulted in the formation of mononuclear [MoOCl2(HL)] (in ethanol) and [MoOCl2(H2L)]Cl (in acetonitrile) or dinuclear oxomolybdenum(V) complexes [Mo2O3(L)2] or [Mo2O3(HL)2]Cl2. Dinuclear molybdenum(V) complexes were also prepared by the reduction of the mononuclear [MoO2(L)(MeOH], [MoO2(HL) (MeOH)]Cl or polynuclear complexes [MoO2(L)]n, [{; ; ; MoO2(HL)}; ; ; Cl]n with PPh3. Molybdenum(VI) complexes with tridentate ligands, as well as, hybrid organic-inorganic polyoxomolybdates were used as (pre)catalysts for olefin epoxidation under solvent-free conditions. All products were identified by means of elemental analysis and characterized by IR, UV-Vis spectroscopy, NMR, TGA, DSC, magnetochemical measurements (VSM, EPR) and X- ray diffraction on polycrystalline and monocrystal samples.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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