Packing and Conformational Polymorphism in 1,2-Bis(aminocarbonyl(1-tert-butyl-1H-pyrazol-(3)5-yl))ethanes: Illuminating Examples of Highly Flexible Molecules

• DOI: 10.1021/acs.cgd.1c00541
• Publication Date: 2021-07-07T18:11:27Z
• Authors: Geórgia C. Zimmer; Anderson B. Pagliari; Vanessa B. Solner; Manfredo Hörner; Helio G. Bonacorso; Nilo Zanatta; Marcos A. P. Martins
• Keywords: Anhydrous; Pyrazole; Amide

Insights into the occurrence of packing and conformational polymorphs anhydrous/hydrate forms 1,2-bis(aminocarbonyl(1-tert-butyl-1H-pyrazol-[3]5-yl))ethanes with substituents R = Me (a), F-4-Ph (b), Cl-4-Ph (c), Br-4-Ph (d) in positions 5 (1) 3 (2) pyrazole rings are presented. In this series, two molecular were observed, linear folded. Compound 1a revealed an illuminating rare example a highly flexible molecule polymorphism. The stacking absence NH···O═C interactions promoted polymorph growth. Structure 2a showed chains driven by bonds anhydrous form closed dimers water binding molecules (NHamide···OHwt···C═Oamide) hydrate form. Two different observed for 2d (linear folded). folded was about −10 kcal mol–1 more stable than form, showing significant crystalline differences. This is attributed to rotation amide groups through bonds. shape higher stabilization energy cluster −6 2dI. Compounds 1b–d 2b-c also had their crystal growth proposed features highlighted.