Application of the method for visualization of noncovalent interactions in conformational polymorphs of four organic acids

Abstract

A method for the visualization of noncovalent interactions using examples of the conformational polymorphs of four organic compounds: 2-(phenylamino)nicotinic, 2-(3-chloro-2-methylphenylamino)nicotinic, N-(3-chloro-2-methylphenyl)anthranilic and 2-(methylphenylamino)nicotinic acids is examined. The changes in noncovalent contacts are plotted against the angle between the planes of aromatic rings allowing a visual representation of conformational adjustment of molecules as well as packing features of crystal structures. According to the k–Φ criterion, the studied structures represent conformational polymorphs. Different types of hydrogen bonding are discussed within the framework of the method of visualization and molecular Voronoi–Dirichlet polyhedra. Good correlations are found between calculated and experimental data for several cases, such as the agreement between π stacking and polymorphic transition temperatures as well as between the area of a contact and the energy of conjugation. Also, an attempt has been made to assess the relative contributions of conformational and packing polymorphism in the formation of polymorphs.

Features of noncovalent interactions in the group of highly polymorphic benzenesulfonamide derivatives

“…These values are very similar to those for polymorphic crystal structures of several organic acids 23 and for other compounds mentioned in the articles in ref. [16][17][18][19][20][21][22]24 and 25.…”

“…Later in the article in ref. 23 on the example of polymorphs of the 2-(phenylamino)-nicotinic acid (CSD refcode family {TOKSAO}) it has been found that the sums of the face area corresponding to intermolecular H⋯C and C⋯C contacts are in good correlation with the temperatures of polymorphic transitions. A similar correlation was found in this work on the example of sulfamethoxazole, which is logical, as the structure of sulfamethoxazole crystals should be largely determined by π stacking (Fig.…”

“…Despite having some obvious shortcomings, for example, the inability to obtain interaction energies, the MVDP method has repeatedly proved its effectiveness in the study of highly polymorphic compounds. In particular, a complete analysis of noncovalent interactions in 8 polymorphic modifications of flufenamic acid, 19 9 polymorphic modifications of aripiprazole, 20 10 polymorphic modifications of galunisertib 21 and 11 of its solvates, 22 as well as in a series of other compounds, [16][17][18]23,24 has been previously performed. Also, 12 polymorphs of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (known as 'ROY'), which is currently the champion in the number of structurally characterized modifications, have already been subjected to similar studies.…”

New Polymorphic Structures of Uranyl Butyrate and Crotonate

“…Analysis of non-covalent interactions was performed within the framework of the method of molecular VDP. [46,47] The molecular complexes of diaquadicarboxylatodioxidouraium(VI) in the polymorphic structures interact with each other preferentially by H/ H and H/O contacts (Figure 3). Partial contribution Δ (calculated as the sum of face area of intermolecular H/H or H/O contacts divided by the whole surface of molecular VDP and multiplied by 100 %) of H/H contacts is higher for uranyl butyrates due to the saturated carboxylate ion alkyl chain.…”