research papers
Molecules of 2-ethyl-1-[5-(4-methylphenyl)pyrazol-3-yl]-3-(thiophene-2-carbonyl)isothiourea, formed by reaction of S,S-diethyl 2-thenoylimidodithiocarbonate with 5-amino-3-(4-methylphenyl)-1H-pyrazole, form hydrogen-bonded ribbons in which centrosymmetric (4) and (6) rings alternate.
research papers
In a substituted pyrazolo[1,5-a][1,3,5]triazine, centrosymmetric dimers generated by C-HO hydrogen bonds are linked into chains by a - stacking interaction.