Polymorphism and phase transformations in 2,6-disubstituted N-phenylformamides: the influence of hydrogen bonding, chloro-methyl exchange, intermolecular interactions and disorder

Omondi, Bernard; Fernandes, Manuel A.; Layh, Marcus; Levendis, Demetrius C.; Look, Jennifer; Mkwizu, Tumaini S.

doi:10.1039/b513882e

Cited by 24 publications

(41 citation statements)

References 26 publications

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“…The structures of (I)-(V) and (VII) have been reported previously by us (Omondi et al, 2005;Omondi, Lemmerer et al, 2009;Omondi & Levendis, 2012). The structure of (VI) has been reported previously by Chitanda et al (2008).…”

Section: Crystal Structures Of the Starting Materials (I)-(vii)supporting

confidence: 70%

“…2,6-Disubstituted N-phenylformamides and N-phenylthioamides were synthesized using methods reported previously (Omondi et al, 2005Omondi, Lemmerer et al, 2009;Fernandes & Reid, 2003;Ugi et al, 1965). The starting materials, in a 1:1 stoichiometric ratio of the following: 1 (Ia) and (IIa) for (1), (IIa) and (III) for (2), (IV) and (V) for (3), and (VI) and (VII) for (4), were then dissolved in an appropriate solvent (a single solvent or a mixture that dissolved both ground compounds equally well), The two conformations commonly adopted by the hydrogen-bonded functional group for the formamides and thioamides, in this case shown for the formamide case only.…”

Section: Preparation Of Solid Solutions (1)-(4)mentioning

confidence: 99%

“…S and O atoms or methyl and ethyl groups) can replace each other without affecting the overall crystal structures of these compounds (Nayak et al, 2012). In earlier work, we have observed that replacement of Cl and methyl groups in a series of 2,6-disubstituted N-phenylformamides result in isostructural crystal structures, some of which undergo reversible thermal phase transformations (Omondi et al, 2005;. When similar exchanges of substituents were carried out using the analogous thioamides, isostructural crystals could also be isolated (Omondi, Lemmerer et al, 2009).…”

Section: Introductionmentioning

confidence: 98%

“…Importantly, the compounds can exist as either cis or trans isomers, depending on their physical state (liquid or solid; Fig. 2), and have been observed to exist as a mixture of cis and trans isomers in solution (Gowda et al, 2000;Omondi, Lemmerer et al, 2009;Omondi et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Formation of isostructural solid solutions in 2,6-disubstitutedN-phenylformamides andN-phenylthioamides

Omondi¹,

Lemmerer²,

Fernandes³

et al. 2013

Acta Crystallogr Sect B

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In order to investigate possible isostructural solid solutions of disubstituted N-phenylformamides and thioamides, we have studied the re-crystallization of pairs of compounds selected from 2,6-difluoro-N-phenylformamide (I), 2,6-dichloro-N-phenylformamide (II), 2,6-dimethyl-N-phenylformamide (III), 2,6-dichloro-N-phenylthioamide (IV), 2,6-dimethyl-N-phenylthioamide (V), 2,6-diisopropyl-N-phenylformamide (VI) and 2,6-diisopropyl-N-phenylthioamide (VII). For single-component 2,6-disubstituted-N-phenylformamides only the trans form occurs in the pure crystal, while for thioamides the cis form occurs, with only one exception. By forming solid solutions of pairs of these molecules the resulting structures all adopt similar N-H...O/S chains in the crystals. Solid solutions (1), (2) and (3), resulting from the mixing of (I) and (II), (II) and (III), and (IV) and (V), respectively, are all isostructural with each other (space group Pbca). Only co-crystal (1) is isostructural to both starting materials, while (2) is isostructural to only one of the starting pair, (II). Solid solution (3), which adopts the same Pbca structure as (1) and (2), is different to the monoclinic structures of both the reactants. Solid solution (4) is monoclinic, with similar hydrogen-bonded chains, and isostructural to the two components, resulting from the composition from the mixing of (VI) and (VII). Isostructural indices were used to quantify crystal-packing similarities and differences. Occupancy factors of the reactants in each co-crystal differ widely.

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Section: Crystal Structures Of the Starting Materials (I)-(vii)supporting

confidence: 70%

Section: Preparation Of Solid Solutions (1)-(4)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Formation of isostructural solid solutions in 2,6-disubstitutedN-phenylformamides andN-phenylthioamides

Omondi¹,

Lemmerer²,

Fernandes³

et al. 2013

Acta Crystallogr Sect B

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show abstract

“…

In the crystal structure of the title compound, C 7 H 5 Br 2 NO, molecules related by translation are linked through N-HÁ Á ÁO hydrogen bonds to form chains in the crystallographic a direction, with the aryl rings stacked parallel to each other along the chain. Previous reports showed the effect of different interactions (N-HÁ Á ÁO hydrogen bonds and C-HÁ Á ÁO, ClÁ Á ÁCl andintermolecular interactions) on the phase transitions of 2-chloro-6-methyl-N-phenylformamide (Omondi et al, 2005). 1), is of interest as part of a study on polymorphism and phase transformations in 2,6-disubstituted N-phenylformamides.

…”

mentioning

confidence: 99%

N-(2,6-Dibromophenyl)formamide

Omondi¹,

Levendis²,

Layh³

et al. 2009

Acta Crystallogr C

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In the crystal structure of the title compound, C(7)H(5)Br(2)NO, molecules related by translation are linked through N-H...O hydrogen bonds to form chains in the crystallographic a direction, with the aryl rings stacked parallel to each other along the chain. Besides the N-H...O hydrogen bonds, Br...O and Br...Br intermolecular interactions complete the packing of molecules in the crystal structure.

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Magnetic phase transition in valence tautomers as polymorphs of 3-iodolawsone: Single crystal X-ray structure, DSC and EPR studies

Zaware

Dagade-Waghmode

Gonnade

et al. 2009

Journal of Molecular Structure

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Polymorphism and phase transformations in 2,6-disubstituted N-phenylformamides: the influence of hydrogen bonding, chloro-methyl exchange, intermolecular interactions and disorder

Cited by 24 publications

References 26 publications

Formation of isostructural solid solutions in 2,6-disubstitutedN-phenylformamides andN-phenylthioamides

Formation of isostructural solid solutions in 2,6-disubstitutedN-phenylformamides andN-phenylthioamides

N-(2,6-Dibromophenyl)formamide

Magnetic phase transition in valence tautomers as polymorphs of 3-iodolawsone: Single crystal X-ray structure, DSC and EPR studies

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