Abstract
Co-crystallization from methanol of 3-amino-1H-pyrazole with 3,5-di-nitro-benzoic acid produces 3-amino-1H-pyrazol-2-ium 3,5-di-nitro-benzoate monohydrate, C3H6N3 +·C7H3N2O6 -·H2O, (I), while similar co-crystallization of this pyrazole with an equimolar qu-antity of fumaric acid produces bis-(3-amino-1H-pyrazol-2-ium) fumarate-fumaric acid (1/1), 2C3H6N3 +·C4H2O4 2-·C4H4O4, (II). The reaction of 3-amino-1H-pyrazole with a dilute solution of nitric acid in methanol yields a second, ortho-rhom-bic polymorph of 3-amino-1H-pyrazol-2-ium nitrate, C3H6N3 +·NO3 -, (III). In each of (I)-(III), the bond distances in the cation provide evidence for extensive delocalization of the positive charge. In each of (I) and (II), an extensive series of O-H⋯O and N-H⋯O hydrogen bonds links the components into complex sheets, while in the structure of (III), the ions are linked by multiple N-H⋯O hydrogen bonds into a three-dimensional arrangement. Comparisons are made with the structures of some related compounds.
Highlights
Co-crystallization from methanol of 3-amino-1H-pyrazole with 3,5-dinitrobenzoic acid produces 3-amino-1H-pyrazol-2-ium 3,5-dinitrobenzoate monohydrate, C3H6N3+ÁC7H3N2O6ÀÁH2O, (I), while similar co-crystallization of this pyrazole with an equimolar quantity of fumaric acid produces bis(3-amino-1Hpyrazol-2-ium) fumarate–fumaric acid (1/1), 2C3H6N3+ÁC4H2O42ÀÁC4H4O4, (II)
In each of (I) and (II), an extensive series of O—HÁ Á ÁO and N—HÁ Á ÁO hydrogen bonds links the components into complex sheets, while in the structure of (III), the ions are linked by multiple N—HÁ Á ÁO hydrogen bonds into a threedimensional arrangement
As part of a general study of novel pyrazole derivatives (Asma et al, 2018; Kiran Kumar et al, 2020; Shaibah et al, 2020a,b; Shreekanth et al, 2020), we have synthesized two organic salts derived from 3-amino-1Hpyrazole, namely 3-amino-1-pyrazol-2-ium 3,5-dinitrobenzoate monohydrate (I) (Fig. 1 and Scheme) and bis(3-amino-1pyrazol-2-ium) fumarate fumaric acid (II) (Fig. 2), whose molecular and supramolecular structures are reported here
Summary
Pyrazoles exhibit a very wide range of pharmacological and other biological activities, which have recently been extensively reviewed (Ansari et al, 2017; Karrouchi et al, 2018). As part of a general study of novel pyrazole derivatives (Asma et al, 2018; Kiran Kumar et al, 2020; Shaibah et al, 2020a,b; Shreekanth et al, 2020), we have synthesized two organic salts derived from 3-amino-1Hpyrazole, namely 3-amino-1-pyrazol-2-ium 3,5-dinitrobenzoate monohydrate (I) (Fig. 1 and Scheme) and bis(3-amino-1pyrazol-2-ium) fumarate fumaric acid (II) (Fig. 2), whose molecular and supramolecular structures are reported here. We have isolated a second polymorph of 3-amino-1-pyrazol-2-ium nitrate (III). When crystallized from methanol, this compound forms an orthorhombic polymorph in space group Pna; a monoclinic polymorph in space group P21/c, isolated from aqueous solution has recently been reported (Yamuna et al, 2020). E77, 34–41 discuss the molecular and supramolecular structures of both polymorphs of the nitrate salt
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