U okviru ovog rada opisani su uvjeti priprave simetričnih disupstituiranih (tio)karbonohidrazida izvedenih iz 2-hidroksi-3-metoksibenzaldehida, 2-hidroksi-4-metoksibenzaldehida te 2-hidroksi-5- metoksibenzaldehida. Također, opisani su i uvjeti priprave kompleksnih spojeva molibdena(VI) s dobivenim disupstituiranim (tio)karbonohidrazidima kao ligandima. Svi su spojevi pripravljeni ”klasičnom” otopinskom sintezom u metanolu. Ukupno je priređeno petnaest novih spojeva, od čega je sedam organskih te osam kompleksnih spojeva molibdena(VI). Reakcijama disupstituiranih karbonohidrazida (H4L) s [MoO2(acac)2] u metanolu nastali su isključivo dinuklearni kompleksi opće formule [(MoO2)2(L)(D)2], gdje L4– predstavlja tetraanionski oblik karbonohidrazidnog liganda, a D predstavlja pomoćne ligande, molekule metanola odnosno vode. Oba atoma molibdena u kompleksu karakterizira deformirana oktaedarska geometrija. U svim je slučajevima geometrija kompleksa takva da su molekule pomoćnih liganada smještene međusobno u cis položaj uzimajući u obzir ravninu karbonohidrazidnog liganda. Reakcije disupstituiranih tiokarbonohidrazida (H4T) u metanolu dale su bez iznimke mononuklearne kompleksne spojeve tipa [MoO2(H2T)(MeOH)], gdje H2T2– predstavlja dianionski oblik tiokarbonohidrazidnog liganda. U odnosu na karbonohidrazidne komplekse, u ovima samo jedna podjedinica liganda sudjeluje u vezanju na [MoO2]2+ jedinku, dok druga ostaje slobodna. Identifikacija i karakterizacija svih pripravljenih spojeva provedena je na temelju podataka infracrvene spektroskopije, termogravimetrijske analize, u određenim slučajevima spektroskopije nuklearne magnetne rezonancije, difrakcije rentgenskih zraka na praškastim uzorcima, te u slučajevima kada je to bilo moguće, difrakcije rentgenskih zraka na jediničnom kristalu.

Synthesis of symmetrical disubstituted (thio)carbohydrazides derived from 2-hydroxy-3- methoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde and 2-hydroxy-5-methoxybenzaldehyde are described in this thesis. Also, reaction conditions for preparing complex compounds of molybdenum(VI) with the obtained disubstituted (thio)carbohydrazides as ligands are described. All of the compounds were prepared via "classical" solution synthesis in methanol. A total of fifteen new compounds were synthesized, seven of which are organic molecules and the remaining eight are molybdenum(VI) complex compounds. The reactions of disubstituted carbohydrazides(H4L) with dioxobis(pentane-2,4-dionato) molybdenum(VI), [MoO2(acac)2] in methanol generated dinuclear complexes exclusively, with the general formula [(MoO2)2(L)(D)2], wherein L4- represents a tetraanionic form of a carbohydrazide ligand and D represents auxiliary ligands, methanol or water molecules. Both molybdenum atoms in the complex are found in octahedral environment. In all cases, the auxiliary ligand molecules are positioned mutually in the cis position regarding the carbohydrazide ligand plane. The reactions of disubstituted thiocarbohydrazide (H4T) in methanol yielded solely the mononuclear complexes of the type [MoO2(H2T)(MeOH)], where H2T2- represents a dianionic form of thiocarbohydrazide ligand. On contrary to the carbohydrazide complexes, only one subunit of ligand participates in binding to [MoO2]2+, while the other remains uncoordinated. All compounds were identified and characterized by means of infrared spectroscopy, thermal analysis, and in some cases NMR spectroscopy, X-ray powder diffraction and when it was possible single-crystal X-ray diffraction.