Preference of High-Nitrogen-Content Compounds to Form Hydrates and the Tandem Contacts of Azide Groups

Abstract

High-pressure isochoric recrystallizations lead to new forms of these compounds. The α-hydrate can be reversibly isothermally compressed to 0.6 GPa at the least and the β-hydrate can be compressed to and from 1 GPa. However, the isochoric recrystallizations above 0.3 GPa favor the α-hydrate. This hydrate occurs as metastable phase, in accordance with the Ostwald rule of stages. Compound C 7 H 7 N 7 could be recrystallized only from aqueous solution in the form of sesquihydrate C 7 H 7 N 7 •1.5H 2 O. The molecular packing in all hydrates is governed by hydrogen bonds OH•••N and tandem contacts between azide groups.

Low-density preference of the ambient and high-pressure polymorphs of DL-menthol

“…The smooth compression of the crystal volume and unit-cell parameters are indications that the crystal remains in the same phase, whereas anomalous compression (discontinuities or changed rate of compression) would indicate phase transitions to other phases. Generally, the absence of detectable anomalies cannot be directly connected with the thermodynamic stability of crystalline or liquid phases, because of the possible effects of supercompressing (Katrusiak et al, 2011;Paliwoda et al, 2012;Anioła & Katrusiak, 2015;Roszak et al, 2016;Fedorov et al, 2017;Sobczak & Katrusiak, 2017;Safari & Katrusiak, 2021;Olejniczak et al, 2022b) or supercooling (Weineerg, 1908) the phases.…”

“…This new polymorph -dl-menthol could not be obtained by compressing the ambient-pressure polymorph up to 3.37 GPa. Such high-pressure polymorphs, accessible via in situ recrystallization under pressure, were found for imidazole ( (4) À 52 (1)p + 18 (2)p 2 À 2.5 (6)p 3 and V (p) = 255 (2) À 21 (6)p À 1(7)p 2 + 1(2)p 3 hydrobromide monohydrate (Anioła & Katrusiak, 2015), 3hydroxy-4,5-dimethyl-1-phenylpyridazin-6-one (Roszak et al, 2016), di-p-tolyl disulfide (Sobczak & Katrusiak, 2017), resorcinol (Safari & Katrusiak, 2021) and other compounds (Fedorov et al, 2017;Olejniczak et al, 2022b). However, the molecular volume of those polymorphs accessible through recrystallization is smaller compared with the compressed ambient-pressure polymorph.…”

Tetrel bonding stabilization of a new coordination polymer constructed from lead(ii) azide and 1-(pyridin-2-yl)ethylidenepicolinohydrazide

“…It is an intriguing outcome in the light of the recent report by Olejniczak and co-workers, where attractive azide–azide interactions in triazolo-pyridazine based crystals are suggested. 30 It shall also be referenced that the N 3 units can in some systems be bonded through a σ-hole to electron donors. 31,32 It is further shown herein that both the Pb–N and weaker tetrel-type Pb⋯N connections are driven by the same prevailing Coulomb-type physical mechanism.…”

High Pressure Study of Pharmaceutical and Energetic Material Hexamethylenetetramine

“…31−36 The transition from phase III to phase I of piracetam has been examined under experimental conditions involving compression of phase III to 0.2 GPa at 443 K. 37 Additionally, the compression of phase II of piracetam within pressure ranges of 0.45−0.70 GPa induced a reversible, single-crystal to singlecrystal transition, resulting in a novel polymorph, phase V. 38 High-pressure isochoric recrystallizations have yielded new forms of 6-azido-7-methyl [1,2,4]triazolo [4,3-b]pyridazine (C 6 H 5 N 7 ). 39 Gao et al confirmed that pressure-induced molecular deformations led to a reduction in molecular symmetry through high-pressure Raman studies. β-RDX first transitioned to ε′-RDX at approximately 0.9 GPa, in proximity to ε-RDX at high temperature and pressure.…”

“…Additionally, the compression of phase II of piracetam within pressure ranges of 0.45–0.70 GPa induced a reversible, single-crystal to single-crystal transition, resulting in a novel polymorph, phase V . High-pressure isochoric recrystallizations have yielded new forms of 6-azido-7-methyl­[1,2,4]­triazolo­[4,3- b ]­pyridazine (C 6 H 5 N 7 ) . Gao et al confirmed that pressure-induced molecular deformations led to a reduction in molecular symmetry through high-pressure Raman studies.…”