The goal of this thesis was to produce co-crystals of pyridine-N-oxide with benzoic acid and co-crystals of 4-nitropyridine N-oxide with the following derivatives of benzoic acid: salicylic acid, 2,6-dihydroxybenzoic acid and 2-fluoro benzoic acid. Syntheses were performed with crystallization. The reactants were at first grinded and after that solvent was added. This mixture was then heated until 70 °C while also mixed. After that we tried to grow co-crystals by cooling and slow evaporation of the solvent. These products were analysed by X-ray diffraction and in some cases with IR spectroscopy and CHN analysis. According to the literature data, we managed to repeat the synthesis of co-crystals of 4-nitropyridine N-oxide and salicylic acid (co-crystal 1). By the same synthetic procedure (using 2,6-dihydroxybenzoic instead of salicylic acid) new co-crystals, which haven’t been reported in the literature yet, that is co-crystals of 4-nitropyridine N-oxide and 2,6-dihydroxybenzoic acid (co-crystal 2), were prepared. Their crystal structure was determined by X-ray single crystal diffraction. In co-crystals 2 acid molecules are bonded via carboxylic group to O atom of nitroso group of 4-nitropyridine N-oxide with a strong hydrogen bond, which is probably the main driving force for the existence of these co-crystals. The product was characterized also by X-ray powder diffraction, IR spectroscopy and CHN analysis. The results of these analyses were in the agreement with the results of structure analysis.
Other syntheses were not successful. When we wanted to produce co-crystals of 4-nitropyridine N-oxide with 2-fluoro benzoic acid, we got a mixture of crystals of starting solids instead of co-crystals. The experiments of producing of co-crystals of pyridine-N-oxide with benzoic acid were also unsuccessful because of high hygroscopicity of pyridine-N-oxide and air’s moisture. That was the reason why pyridine-N-oxide did not percipitate neither itself nor in the form of co-crystals.
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