Revisiting 2-chloro-4-nitroaniline: analysis of intricate supramolecular ordering of a triclinic polymorph featuring a high <i>Z</i> value and strong second harmonic generation

Medviediev, Volodymyr V.; Shishkina, Svitlana V.; Ribalka, Andrii; Zarȩba, Jan K.; Drozd, M.; Daszkiewicz, Marek

doi:10.1039/d0ce00582g

Cited by 6 publications

(3 citation statements)

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“…Polymorphism, by definition, is the occurrence of multiple crystalline forms of the same compound . It is one of the important research themes in the crystal engineering community and finds practical applications in the pharmaceutical industry. , Polymorphic crystal systems which crystallize as both high- Z ′ and low- Z ′ forms are particularly useful, as they are directly comparable at the structural level to provide insights on structural stability and molecular reorganization aspects during phase transformations. ,,,,,,− According to Desiraju, , high- Z ′ forms can provide important clues as to how low- Z ′ forms evolve from high- Z ′ forms during the late stage events of crystallization. Phase transitions induced by temperature, − pressure, − force, and oil have been reported, and the studies emphasized that small structural variations between the parent and daughter structures are very important to facilitate a single-crystal to single-crystal phase transformation.…”

Section: Introductionmentioning

confidence: 99%

Conformational Polymorphism in Safinamide Acid Hydrochloride (Z′ = 3 and Z′ = 1) and Observation of a Temperature-Dependent Reversible Single-Crystal to Single-Crystal Phase Transformation of High-Z′ form (Z′ = 3 ↔ Z′ = 2 via an Intermediate Z′ = 4)

Nanubolu

2020

Crystal Growth & Design

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Two concomitant polymorphs of safinamide acid hydrochloride were obtained in an attempt to prepare the O-protonated amide salt of safinamide from ethanolic HCl solution. Polymorph I crystallized in the triclinic space group P1 with three molecules in the asymmetric unit (Z′ = 3) while polymorph II crystallized in the orthorhombic space group P2 1 2 1 2 1 with a single molecule in the asymmetric unit (Z′ = 1). Structural differences at the conformational level and their influence on intermolecular interactions in the crystals led to the occurrence of polymorphism in the title compound. Both Z′ = 1 and Z′ = 3 polymorphic forms of safinamide acid hydrochloride were sustained by similar strong O−H••• Cl − and N + −H•••Cl − hydrogen-bonded interactions but differed significantly in the molecular conformations and hence their molecular arrangements in the crystal lattice. The C−H•••O and C−H•••F hydrogen bonds along with the strong hydrogen bonds facilitated one-dimensional supramolecular aggregates and caused the occurrence of the Z′ > 1 situation. The high-Z′ polymorph showed an interesting phase transition behavior during variable-temperature single-crystal X-ray diffraction studies (VT-SCXRD). When the sample was rapidly cooled from 293 K (room temperature) to 100 K (low temperature), the Z′ = 3 polymorph was stable; however, when the same crystal was subjected to gradual cooling from room temperature to 100 K, the Z′ = 3 polymorph transformed to a novel Z′ = 2 structure (in the transition temperature range 260−265 K). When the sample was warmed from 100 K to RT, the phase transition was found to be reversible from Z′ = 2 to Z′ = 3 (in the transition temperature range 270−275 K). Differential scanning calorimetry studies were conducted to confirm the reversible phase transition nature (Z′ = 3 ↔ Z′ = 2). An intermediate short-lived crystal form with four molecules in the asymmetric unit (Z′ = 4) was captured at 272 K during the VT-SCXRD warming cycle, which facilitated a better understanding of the structural reorganization process during the phase transition. The Z′ = 4 structure can be referred as a "crystal on the way" in the Z′ = 2 to Z′ = 3 phase transition. The close structural similarities among Z′ = 3, 2, and 4 accounted for the phase transformation in a single-crystal to single-crystal manner.

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Section: Introductionmentioning

confidence: 99%

Conformational Polymorphism in Safinamide Acid Hydrochloride (Z′ = 3 and Z′ = 1) and Observation of a Temperature-Dependent Reversible Single-Crystal to Single-Crystal Phase Transformation of High-Z′ form (Z′ = 3 ↔ Z′ = 2 via an Intermediate Z′ = 4)

Nanubolu

2020

Crystal Growth & Design

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“…An overview of high- Z ′ crystal structures, where Z ′ > 1 is the result of a modulation of the molecular geometry, has been given by Brock and Taylor . Furthermore, a Z ′ = 8 modulated structure has been discovered for 2-chloro-4-nitroaniline, however, without information on a possible low- Z ′ phase.…”

Section: Resultsmentioning

confidence: 99%

Toward Understanding High-Z′ Organic Molecular Crystals through the Superspace Method: The Example of Glycyl-l-valine

Rekis

Schönleber

Noohinejad

et al. 2021

Crystal Growth & Design

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The high-Z′ (Z′ = 7) structure of glycyl-l-valine has been redetermined at 298 K, using synchrotron radiation and exploiting the superspace approach. The analysis of the diffraction data reveals that the structure can be described as a commensurately modulated crystal structure with superspace group P212121(0σ20)000 and modulation wave vector q = (0, 2/7, 0). A new Z′ = 1 phase has been discovered for this compound at 323 K that is related to the known Z′ = 7 phase. The origin of the modulated phase has been explored by analyzing intermolecular interactions and molecular conformations in terms of t-plots and through a comparison to (1) the newly discovered high-temperature phase, (2) a hypothetical Z′ = 1 structure at 298 K, and (3) a similar Z′ = 1 structure of the related compound glycyl-l-leucine. The results show that the conformational flexibility of the glycyl-l-valine molecule ensures optimization of the hydrogen-bond network which causes the modulation and thus a high Z′ value of the supercell. This study highlights the elegance and convenience of the superspace approach to explain the occurrence of at least part of the rarely occurring high-Z′ structures of molecular compounds.

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“…2Cl4na is an analogue of 2m4na, where the methyl group was substituted by the Cl atom and the position of the nitro group with respect to the NH 2 group is preserved, whereas 2m6na is a constitutional isomer of 2m4na. The crystal structure of 2Cl4na was reported a long time ago (McPhail & Sim, 1965), but a new polymorph was discovered recently (Medviediev et al, 2020b). Both polymorphs of 2Cl4na are surprisingly noncentrosymmetric, i.e.…”

Section: Introductionmentioning

confidence: 99%

Structural and theoretical analysis of 2-chloro-4-nitroaniline and 2-methyl-6-nitroaniline salts

Medviediev

Daszkiewicz

2021

Acta Crystallogr C

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The crystal structures of five new salts of 2-chloro-4-nitroaniline (2Cl4na) and 2-methyl-6-nitroaniline (2m6na) with inorganic acids, namely, 2-chloro-4-nitroanilinium bromide, C6H6ClN2O2 +·Br− (1), 2-chloro-4-nitroanilinium hydrogen sulfate, C6H6ClN2O2 +·HSO4 − (2), 2-methyl-6-nitroanilinium bromide, C7H9N2O2 +·Br− (3), 2-methyl-6-nitroanilinium triiodide, C7H9N2O2 +·I3 − (4), and 2-methyl-6-nitroanilinium hydrogen sulfate, C7H9N2O2 +·HSO4 − (5), were determined by single-crystal X-ray diffraction. Theoretical calculations of the relaxed potential energy surface (rPES) revealed that the energy barriers for the rotation of the nitro group for isolated H2Cl4na+ and H2m6na+ cations are 4.6 and 11.6 kcal mol−1, respectively. The ammonium group and respective anions form hydrogen bonds which are the most important interactions and are arranged in zero- (in 3), one- (in 1 and 4) or two-dimensional (in 2 and 5) networks. Hydrogen-bonding patterns were analyzed by means of mathematical relationships between graph-set descriptors and compared with previously reported nitroaniline salts. Hirshfeld surface analysis indicates that the nitro group plays a dominant role among the weak interactions, i.e. C—H...O(NO2), NO2...π(Ar) and O(NO2)...π(NO2). The frequency of the νsNO2 vibration is correlated with the type of interaction in which the NO2 group is involved. Analysis of the νsNO2 band observed in the IR and Raman spectra allowed an assessment of its shift in the sequence (H2m6na)I3 (4) < (H2m6na)HSO4 (5) < (H2m6na)Br (3) < (H2Cl4na)Br (1) < (H2Cl4na)HSO4 (2).

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Revisiting 2-chloro-4-nitroaniline: analysis of intricate supramolecular ordering of a triclinic polymorph featuring a high Z value and strong second harmonic generation

Abstract:
Polymorphism represents an expanding area of crystal engineering and an opportunity for discovery of materials with interesting properties, thus giving a new perspectives for “old”, well-known compounds known by chemists...

Cited by 6 publications

References 58 publications

Conformational Polymorphism in Safinamide Acid Hydrochloride (Z′ = 3 and Z′ = 1) and Observation of a Temperature-Dependent Reversible Single-Crystal to Single-Crystal Phase Transformation of High-Z′ form (Z′ = 3 ↔ Z′ = 2 via an Intermediate Z′ = 4)

Conformational Polymorphism in Safinamide Acid Hydrochloride (Z′ = 3 and Z′ = 1) and Observation of a Temperature-Dependent Reversible Single-Crystal to Single-Crystal Phase Transformation of High-Z′ form (Z′ = 3 ↔ Z′ = 2 via an Intermediate Z′ = 4)

Toward Understanding High-Z′ Organic Molecular Crystals through the Superspace Method: The Example of Glycyl-l-valine

Structural and theoretical analysis of 2-chloro-4-nitroaniline and 2-methyl-6-nitroaniline salts

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Revisiting 2-chloro-4-nitroaniline: analysis of intricate supramolecular ordering of a triclinic polymorph featuring a high Z value and strong second harmonic generation

Abstract: Polymorphism represents an expanding area of crystal engineering and an opportunity for discovery of materials with interesting properties, thus giving a new perspectives for “old”, well-known compounds known by chemists...

Cited by 6 publications

References 58 publications

Conformational Polymorphism in Safinamide Acid Hydrochloride (Z′ = 3 and Z′ = 1) and Observation of a Temperature-Dependent Reversible Single-Crystal to Single-Crystal Phase Transformation of High-Z′ form (Z′ = 3 ↔ Z′ = 2 via an Intermediate Z′ = 4)

Conformational Polymorphism in Safinamide Acid Hydrochloride (Z′ = 3 and Z′ = 1) and Observation of a Temperature-Dependent Reversible Single-Crystal to Single-Crystal Phase Transformation of High-Z′ form (Z′ = 3 ↔ Z′ = 2 via an Intermediate Z′ = 4)

Toward Understanding High-Z′ Organic Molecular Crystals through the Superspace Method: The Example of Glycyl-l-valine

Structural and theoretical analysis of 2-chloro-4-nitroaniline and 2-methyl-6-nitroaniline salts

Contact Info

Product

Resources

About

Abstract:
Polymorphism represents an expanding area of crystal engineering and an opportunity for discovery of materials with interesting properties, thus giving a new perspectives for “old”, well-known compounds known by chemists...