Occurrence of 3D isostructurality in fluorinated phenyl benzamidines

Abstract

In the current study, we report the existence of 3D isostructurality behaviour in pairs of isomeric molecules existing as E-Z isomers. The polymorphic forms E1 and E2 of (E)-2-fluoro-N′-(3-phenyl) benzimidamide are individually isostructural with (E)-2-fluoro-N′-phenylbenzimidamide and (E)-2-fluoro-N′-(2fluorophenyl) benzimidamide, respectively. Furthermore, a similar compound, (Z)-3-fluoro-N′-(4fluorophenyl) benzimidamide, is isostructural with (Z)-4-fluoro-N′-(4-fluorophenyl) benzimidamide. The structural feature has been analyzed in terms of the nature and energetics of the equivalent supramolecular building blocks associated with the presence of various intermolecular interactions in the crystal packing. The crystal packing similarities have been investigated quantitatively via XPac analysis and the energy vector model. It is noteworthy to observe the presence of a rarely observed N-H⋯F interaction which plays an important role in the crystal packing of [(Z)-3-fluoro-N′-(4-fluorophenyl) benzimidamide]/[(Z)-4-fluoro-N′-(4-fluorophenyl) benzimidamide]. The NCI isosurface signifies the "attractive" nature of the N-H⋯F and N-H⋯π interactions and the different types of C-H⋯F dimeric motifs. An analysis of the two-dimensional fingerprint plots also provides a quantitative understanding of the occurrence of isostructurality in these compounds.

Quantitative analysis of solid-state diversity in trifluoromethylated phenylhydrazones

“…The polymorphic forms of a substance provide a unique opportunity to investigate structure-property relationships in molecular crystals (Mondal et al, 2016(Mondal et al, , 2017. On the other hand, the existence of two different crystal structures with one-, two-or threedimensional structural similarities in their molecular arrangements is termed 'isostructurality' (IUCr, 2014; Fá biá n & Ká lmá n, 2004; Dey & Chopra, 2017). Although these two phenomena oppose each other in terms of the behaviour of the molecules towards the crystal structure, on certain occasions both can co-exist together between two crystal structures, defined as isostructural polymorphism (Coles et al, 2014;Nath et al, 2008;Jha et al, 2016).…”

“…Furthermore, two crystal structures which are isostructural can also exhibit the behaviour of isomorphism (Esteves de Castro et al, 2007;Tykarska & Gdaniec, 2013) having a similar space groups with identical unit-cell parameters. Currently, the interchange between the substituents (such as Cl/CH 3 , H/F or H/CF 3 ) in a molecule is an interesting problem in crystal engineering (Dey & Chopra, 2017;Chopra & Row, 2008;Nayak et al, 2011Nayak et al, , 2012Kaur et al, 2012Kaur et al, , 2016Karanam & Choudhury, 2013;Gelbrich et al, 2012) and it is desirable to rationalize whether this chemical replacement can affect supramolecular assemblies in a significant manner (assuming differences in electronic and steric factors). This has implications for the observation of isostructurality for such compounds in solids.…”

Preferential Orientation of Crystals and its Influence on the Emission Wavelength of Acrylonitrile Derivatives Treated with Polar Solvents

“…Displacement ellipsoid plots are given in Figure . The superimposition of three halogenated structures (F, Cl, and Br) shows that the three molecules are almost planar and isostructural . The overlay of I and II molecular structures and the torsion angles for the molecules remain nearly unchanged and consequently, there is no change in the molecular conformation.…”

Supramolecular Similarity in Polymorphs: Use of Similarity Indices (IX)

“…This happens because a different number of molecules in each example is considered and does not allow a range of comparisons, as observed in recent studies. 38,39 In other words, the x values do not provide clear quantitative information regarding complete crystal structure comparisons. 16…”