Role of organic fluorine in crystal engineering

Chopra, Deepak; Row, Tayur N. Guru

doi:10.1039/c0ce00538j

Cited by 303 publications

(215 citation statements)

References 138 publications

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“…The effects of fluorination on molecular properties are well established, and their use in compound property optimisation in many fields like material 1, 2 and medicinal chemistry, [3][4][5][6] as well as crystal engineering 7,8 and agrochemistry 9,10 benefit from this strong influence. After the debate about the effective ability of fluorine to act as a hydrogen-bond (H-bond, HB) acceptor, [11][12][13][14][15] the occurrence of intermolecular OHF H-bonding is now clearly established through experimental and theoretical evidences.…”

Section: Introductionmentioning

confidence: 99%

α‐Fluoro‐o‐cresols: The Key Role of Intramolecular Hydrogen Bonding in Conformational Preference and Hydrogen‐Bond Acidity

et al. 2016

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The conformational preferences of o-cresols driven by fluorination have been thoroughly investigated from a theoretical point of view with quantum chemical methods and compared to those recently reported for benzyl alcohols. Key conformers of both families exhibit a 6-membered intramolecular hydrogen-bond (IMHB) interaction. A significant enhancement of IMHB strength is observed in -fluoro-o-cresols, owing to the simultaneous increase of the aliphatic fluorine hydrogen-bond (HB) basicity and of the aromatic hydroxyl HB acidity, compared to o-fluorobenzyl alcohols, which are characterized by aromatic fluorine atoms and aliphatic hydroxyl groups. In the case of di-and trifluorinated derivatives, the occurrence of a three-centre hydrogen-bond is emphasised and its features discussed. The impact of these structural predilections on ocresol HB properties has been characterised from the estimation of the HB acidity parameter, pKAHY, weighted according to their conformational populations. We find that -fluorination leads to an HB acidity decrease of the hydroxyl group (in contrast with o-fluorination of benzyl alcohols), whereas ,-difluorination results in no significant variation of pKAHY. Finally, an increase of HB acidity is predicted upon methyl perfluorination, which has been confirmed experimentally. Theoretical descriptors based on AIM, NCI and NBO analyses allows rationalizing the predicted trends, and reveal a relationship with the strength of the established OHF IMHB.

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Section: Introductionmentioning

confidence: 99%

α‐Fluoro‐o‐cresols: The Key Role of Intramolecular Hydrogen Bonding in Conformational Preference and Hydrogen‐Bond Acidity

et al. 2016

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“…This is mainly due to the absence of any naturally occurring Tc isotopes and the radioactivity of those available [1]. Tc oxides are important since 99 Tc is found in nuclear waste and has a long halflife (2.13 × 10 5 yr).…”

Section: N-salicylideneanilinesmentioning

confidence: 99%

“…High selectivity for the desired isomer of the aldehyde can be kinetically manipulated by variation of the ligands and process conditions. In rhodium systems, it is known that the presence of phosphine ligands give way to more active, highly selective catalysts reacting under milder reaction conditions [1].…”

Section: N-salicylideneanilinesmentioning

confidence: 99%

“…2, was analyzed by X-ray using two-photon excitation, and showed pedal-like structural change around the -C=N-bond during the reaction. [1] This reaction begins with a hydrogen atom transfer from hydroxyl group to the nitrogen of the imine, and followed to the pedal motion. Previous X-ray study cannot fi nd the hydrogen atom of the trans-keto form because the population of the photoproduct is only 10% in the single crystal.…”

Section: N-salicylideneanilinesmentioning

confidence: 99%

“…The "organic fluorine" in action in the construction of organometallic molecular materials Alessandra Crispini, a Iolinda Aiello, Mauro Ghedini Fluorine containing organic substituents are currently used to gain control on the solid state supramolecular organization of both organic and inorganic materials [1]. The introduction of CF 3 groups adequately positioned on the rigid core of a molecule, could be sufficient to provide fluorine-fluorine interactions able to modify, in absence of other strong interactions like hydrogen bonding, the packing motifs in the structure of crystalline materials.…”

Section: N-salicylideneanilinesmentioning

confidence: 99%

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