Synthesis and catalytic activity of molibdenum(VI) complexes with 2,4-dihydroxybenzaldehyde derivatives

U okviru ovog rada pripravljena su dva hidrazonska liganda, derivati 2,4-dihidroksibenzaldehida s 2-aminobenzhidrazidom (H2L1), odnosno 4-aminobenzhidrazidom (H2L2). Reakcijom [MoO2(acac)2] i odgovarajućeg aminobenzhidrazona, H2L1,2, pripravljeni su kompleksni spojevi molibdena(VI). Mononuklearni kompleksni spojevi, [MoO2(L)(MeOH)], su dobiveni iz metanolne otopine, a dinuklearni, [MoO2(L)]2, i polinuklearni, [MoO2(L)]n, iz acetonitrilnih otopina. Kompleksni spojevi su identificirani i analizirani metodom infracrvene spektroskopije, nuklearne magnetske rezonancije, termogravimetrijskom i elementnom analizom. Difrakcijom rentgenskog zračenja na jediničnom kristalu je određena molekulska i kristalna struktura oba liganda i dinuklearnog kompleksnog spoja molibdena(VI), [MoO2(L1)]2. Katalitička aktivnost pripravljenih dinuklearnih i polinuklearnih spojeva ispitana je u reakcijama (ep)oksidacije cikloheksena s različitim oksidansima (vodenom otopinom tert-butil hidroperoksida, tert-butil hidroperoksidom u dekanu i otopinom vodikova peroksida), u uvjetima bez dodataka dodatnih organskih otapala u reakcijsku smjesu. Provedene katalitičke reakcije potpomognute su mikrovalnim zračenjem.As part of this diploma thesis, synthesis of two hydrazine ligands, derivatives of 2,4- dihydroxybenzaldehyde with 2-aminobenzhydrazide (H2L1) or 4-aminobenzhydrazide (H2L2). By the reaction of [MoO2(acac)2] and corresponding aminobenzhydrazone ligand, complexes of molybdenum(VI) were synthesized. Two mononuclear complexes [MoO2(L)(MeOH)] were syntesised from a methanolic solution, whereas two dinuclear ([MoO2(L1,2)]2 and one polynuclear [MoO2(L1)]n complexes have been synthesized from acetonitrilic ones. All complexes were identified by the infrared spectroscopy, nuclear magnethic resonance, thermogravimetric and element analysis. Molecular and crystal structures of both of the hydrazone ligands (H2L1, H2L2) and of dinuclear dioxomolybdenum(VI) complex ([MoO2(L1)]2×MeCN) were determined by the single crystal X-ray diffraction. Catalytic activity of dinuclear and polynuclear complexes was tested in the microwave assisted solvent-free (ep)oxidation of cyclohexene with different oxidants (aqueous tert-butyl hydroperoxide, tertbutyl hydroperoxide in decane and hydrogen peroxide solution)