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Crystalline Derivatives of Dipyrazolo-1,5-diazocine and Dipyrazolopyrimidine: A Case of Unexpected Synthesis and Isostructural Polymorphism
- Source :
- Crystals, Vol 12, Iss 5, p 714 (2022)
- Publication Year :
- 2022
- Publisher :
- MDPI AG, 2022.
-
Abstract
- Pyrazole-phenylmethanimines (Shiff bases), Py–N=CH–Ph, form molecular crystals whose supramolecular and self-assembly properties can be tuned according to the substitution made on the aromatic and pyrazole rings. In pursuit of the first pyrazole-pyridinemethanimine member, Py–N=CH–Pyr, by following the well-known synthetic scheme for these Shiff bases, two hitherto unknown crystalline derivatives of dipyrazolo-1,5-diazocine and dipyrazolopyrimidine were obtained instead, this depending on the use or not of acetic acid as the catalyst. 1,5-diazocine crystallizes in a single P-1 triclinic packing system (Z = 2, Z′ = 1), while dipyrazolopyrimidine exhibits isostructural dimorphic behavior by adopting two (pale pink and yellow) alike P21/c monoclinic systems (both Z = 4, Z′ = 1) as a function of the solvent used. Crystal structures were resolved by means of X-ray diffraction technique and their intramolecular, intermolecular, and supramolecular assemblies analyzed with the assistance of decorated Hirshfeld surfaces and the topology study of electron density using the quantum-theory of atoms in molecules (QTAIM). Although both dipyrazolopyrimidine polymorphs are stabilized by the same type of noncovalent motifs, the pale pink crystal has a slightly more compact structure, with more efficient inter- and intramolecular interactions.
Details
- Language :
- English
- ISSN :
- 20734352 and 37834975
- Volume :
- 12
- Issue :
- 5
- Database :
- Directory of Open Access Journals
- Journal :
- Crystals
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.08f4034a50cd4d36b7c3783497549dcb
- Document Type :
- article
- Full Text :
- https://doi.org/10.3390/cryst12050714