The role of weak intermolecular C–H...F interactions in supramolecular assembly: Structural investigations on 3,5- dibenzylidene-piperidin-4-one and database analysis

Abstract

The fluorinated and non-fluorinated dibenzylidene-4-piperidones were synthesized and their structures examined using X-ray crystallography. Interestingly, the para-fluorosubstituted dibenzylidene compound, in contrast to other analogs, is characterized by C-H. . . F bonded one-dimensional packing motif. To evaluate the ability of hydrogen bond donors and acceptors for forming interactions, in general and competitive situation, we have defined statistical descriptors. Analysis of Cambridge Structural Database using these newly defined parameters reveals high propensity of C-H. . . F interactions in organic crystals. The present structural study suggests much larger role of fluorine driven intermolecular interactions that are even though weak, but possess significant ability to direct and alter the packing.

Hückel and Möbius Expanded para‐Benziporphyrins: Synthesis and Aromaticity Switching

“…The distance between the boron atom and the C 5 plane equals 0.164 Å. BN bond lengths equal 1.569(2) and 1.565(2) Å and are similar to distances typically reported for BODIPY complexes 54–56. Distances between the hydrogen atoms H(26) and H(30) and the proximate F atom equal 2.23 and 2.20 Å, respectively, and are slightly shorter than the mean C‐H⋅⋅⋅F distance reported for intermolecular interactions (2.45 Å) 57…”

“…[54][55][56] Distances between the hydrogen atoms H (26) and H(30) and the proximate F atom equal 2.23 and 2.20 , respectively, and are slightly shorter than the mean C-H···F distance reported for intermolecular interactions (2.45 ). [57] The fused pentaphyrin 7 b-H 2…”

Halogen and Hydrogen Bonding Interplay in the Crystal Packing of Halometallocenes

“…Despite their high electronegativity halogens were considered poor acceptors in hydrogen bonds involving strong donors like N or O [ 17 ] due to their low polarizability and very contracted lone pairs (particularly in the case of fluorine) [ 20 , 21 ]. But in the absence of strong donors and acceptors, interactions like C-H⋯X-C were more frequent, even with fluorine [ 20 , 21 , 22 ].…”

4,4′-Difluoro-2,2′-[imidazolidine-1,3-diylbis(methylene)]diphenol

“…Data collection: CrysAlis PRO (Agilent, 2010); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: JANA2006 (Petříček et al, 2006); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: JANA2006. (Rathore et al 2011, Steiner 2002. In recent literature, the importance of interactions involving fluorine as possible tools in crystal engineering has been explored in greater detail (Chopra & Guru Row, 2005).…”

“…For hydrogenbond graph-set nomenclature, see: Bernstein et al (1995). For the involvement of organo halides in hydrogen bonds, see: Rathore et al (2011); Steiner (2002); Chopra & Guru Row (2005). For the extinction correction used, see: Becker & Coppens (1974).…”