New Polymorphic Modifications of 6-Methyluracil: An Experimental and Quantum Chemical Study.

Polymorphism of 6-methyluracil, which affects the regulation of lipid peroxidation and wound healing, has been studied by experimental and quantum chemical methods. Two known polymorphic modifications and two new crystalline forms were crystallized and characterized by single crystal and powder X-ray diffraction (XRD) methods as well as by the differential scanning calorimetry (DSC) method and infrared (IR) spectroscopy. The calculations of pairwise interaction energies between molecules and lattice energies in periodic boundary conditions have shown that the polymorphic form used in the pharmaceutical industry and two new forms and , which can be formed due to temperature violations, may be considered as metastable.

4-[(Benzyl-amino)-carbon-yl]-1-methyl-pyridinium bromide hemihydrate: X-ray diffraction study and Hirshfeld surface analysis.

The hemihydrate of 4-[(benzyl-amino)-carbon-yl]-1-methyl-pyridinium bromide, CHNO·Br·0.5HO, was studied by single-crystal and powder X-ray diffraction methods. In the asymmetric unit, two organic cations of similar conformation, two bromide anions and one water mol-ecule are present.

4-[(Benzyl-amino)-carbon-yl]-1-methyl-pyridinium halogenide salts: X-ray diffraction study and Hirshfeld surface analysis.

Two salts of 4-[(benzyl-amino)-carbon-yl]-1-methyl-pyridinium () with chloride (CHNO·Cl) and bromide (CHNO·Br) anions were studied and compared with the iodide salt. crystallizes in the centrosymmetric space group 2/ while and form crystals in the Sohncke space group 222. Crystals of are isostructural to those of .

Salts of 4-[(benzyl-amino)-carbon-yl]-1-methyl-pyridinium and iodide anions with different cation:iodine stoichiometric ratios.

The two iodide salts, 4-[(benzyl-amino)-carbon-yl]-1-methyl-pyridinium iodide-iodine (2/1), CHNO·I·0.5I, , and 4-[(benzyl-amino)-carbon-yl]-1-methyl-pyridinium triiodide, CHNO·I , , with different cation:iodine atoms ratios were studied. Salt contains one cation, one iodide anion and half of the neutral I mol-ecule in the asymmetric unit (cation:iodine atoms ratio is 1:2).