Structural and computational understanding of weak interactions in “bridge-flipped” isomeric tetrafluoro-bis-benzylideneanilines

Dhingra, Shallu; Barman, Dibya Jyoti; Yadav, Hare Ram; Eyyathiyil, Jusaina; Bhowmik, Pradip K.; Kaur, Parmeet; Adhikari, Debashis; Choudhury, Angshuman Roy

doi:10.1039/c7ce01872j

Cited by 5 publications

(3 citation statements)

References 49 publications

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“…In principle, there are three basic stacking geometries between two aromatic rings: cofacial, parallel‐displaced and edge‐to‐face . Recently, investigation of the crystal packing involving fluorinated organic compounds confirmed that the molecular packing mode could be controlled or tuned via the formation of weak H ··· F, F ··· F and F ··· π contacts . It is well known that the trifluoromethyl group possesses a strong electron‐withdrawing character.…”

mentioning

confidence: 99%

Stacking of Sterically Congested Trifluoromethylated Aromatics in their Crystals – The Role of Weak F···π or F···F Contacts

Albrecht

Pan

et al. 2020

Eur J Org Chem

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confidence: 99%

Stacking of Sterically Congested Trifluoromethylated Aromatics in their Crystals – The Role of Weak F···π or F···F Contacts

Albrecht

Pan

et al. 2020

Eur J Org Chem

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“…We have recently analysed the role of organic fluorine systematically in various series of molecules (Chopra, 2012;Chopra & Guru Row, 2011;Kaur et al, 2012Kaur et al, , 2016Kaur & Choudhury, 2014. In our recent studies, we have demonstrated the significance of fluorine-mediated interactions (C-HÁ Á ÁF, C-FÁ Á ÁF, and C-FÁ Á Á) in a series of fluorinated benzylideneanilines (Chopra, 2012;Chopra & Guru Row, 2011;Kaur et al, 2012Kaur et al, , 2016Kaur & Choudhury, 2014, azobenzenes (Karanam & Choudhury, 2013) and bis-benzylideneanilines (Dhingra et al, 2018). All the molecules studied earlier by us were nearly planar and conformationally less flexible.…”

Section: Introductionmentioning

confidence: 82%

Evaluation of fluorine-mediated intermolecular interactions in tetrafluorinated tetrahydroisoquinoline derivatives: synthesis and computational studies

Singla¹,

Yadav²,

Choudhury³

2020

Acta Crystallogr B Struct Sci Cryst Eng Mater

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Intermolecular interactions involving the aromatic C—F group in the absence of other strong hydrogen bond acceptors is the theme of this article. Weak interactions involving fluorine are known to generate various supramolecular synthons, thereby altering the crystal structures of small organic molecules. It is demonstrated that the weak interactions involving organic fluorine play a major role in directing crystal packing of highly flexible organic molecules like diphenyl tetrahydroisoquinolines reported herein. The intramolecular C—H...F hydrogen bonds are found to be significant in controlling the molecular conformation in specific cases wheras the intermolecular interactions involving the C—F groups result in a wide range of supramolecular synthons involving C—H...F and C—F...F—C interactions. The interactions are studied computationally to provide insight into their energies and the topology of the interactions is studied using Atoms in Molecules. C—H...F—C interactions are found to be quite stabilizing in nature with the stabilization energy of −13.9 kcal mol−1.

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“…At the same time, bridge-flipped isomeric pairs that are not isomorphous may serve as seeds for the preparation of new polymorphs of their formerly non-isomorphous counterparts, providing yet another means for obtaining new solid materials. Isomorphism among bridge-flipped isomers is rare, commonly being prevented by differences in structural features such as preferred molecular conformations and favored intermolecular interactions that include hydrogen bonding and Lewis acid–base contacts. − On the other hand, several examples of isomorphous pairs are known. − Our search for isomorphous bridge-flipped isomers has employed the premise that similar intermolecular interactions occurring in the two isomers would promote their isomorphism. This strategy has been pursued successfully by previous workers who used strong hydrogen-bonding interactions between carboxylic acids and amides to obtain isomorphous crystals in a chloro/methyl exchange .…”

Section: Introductionmentioning

confidence: 99%

Bridge-Flipped Isomers: Searching for Isomorphous Benzylideneanilines and Phenylhydrazones Reveals Unexpected Structures

Kassekert

Smith

Fermanich

et al. 2019

Crystal Growth & Design

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Examination of a series of "bridge-flipped" halogen-and nitrile-substituted benzylideneanilines for isomorphism by single-crystal X-ray diffraction has resulted in the identification of three non-isomorphous pairs:Their crystal structures are rendered unique by differences in solid-state molecular conformation and intermolecular interactions. The crystal structures of N-(4-cyanobenzylidene)-2-bromoaniline (2Bran) and N-(4-cyanobenzylidene)-2-iodoaniline (2Ian) were determined, but upon attempts to prepare their bridge-flipped isomers the unexpected dianilines 1-(2-bromophenyl)-N,N′-bis(4-cyanophenyl)methanediamine (2Brdian) and 1-(2-iodophenyl)-N,N′-bis(4-cyanophenyl)methanediamine (2Idian) were obtained. The crystal structures of 2Brdian and 2Idian were found to be isomorphous, as were the crystal structures of the three pairs 2Clan/2Bran, 2Ian/2CH 3 an (N-(4-cyanobenzylidene)-2methylaniline), and 2CNan/XOXLOM (N-(4-methylbenzylidene)-2-cyanoaniline). Isomorphism involving iodine/methyl and nitrile/methyl exchanges is rare in the Cambridge Structural Database (CSD). The unexpected product meso-(E,E)-1,1′-[1,2bis(4-methylphenyl)ethane-1,2-diyl]-bis [(2-trifluoromethyl)phenyldiazene] (2CF 3 azo) was obtained in an attempt to prepare the phenylhydrazone, and its crystal structure is reported here. Only one other example of this type of compound currently appears in the CSD. Examples of isomorphous bridge-flipped isomers among benzylideneanilines and phenylhydrazones remain rare in spite of their conformational flexibility and steric similarity.

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Structural and computational understanding of weak interactions in “bridge-flipped” isomeric tetrafluoro-bis-benzylideneanilines

Abstract: Structural and computational insights into inter-molecular interactions in isomeric bridge-flipped tetrafluoro-bis-benzylideneanilines.

Cited by 5 publications

References 49 publications

Stacking of Sterically Congested Trifluoromethylated Aromatics in their Crystals – The Role of Weak F···π or F···F Contacts

Stacking of Sterically Congested Trifluoromethylated Aromatics in their Crystals – The Role of Weak F···π or F···F Contacts

Evaluation of fluorine-mediated intermolecular interactions in tetrafluorinated tetrahydroisoquinoline derivatives: synthesis and computational studies

Bridge-Flipped Isomers: Searching for Isomorphous Benzylideneanilines and Phenylhydrazones Reveals Unexpected Structures

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