Hirshfeld Surfaces Identify Inadequacies in Computations of Intermolecular Interactions in Crystals: Pentamorphic 1,8-Dihydroxyanthraquinone

Abstract

Fingerprint plots of Hirshfeld surfaces were used to locate and analyze the deficiencies in various methodologies employed in the determination of the relative energies of five polymorphs of 1,8-dihydroxyanthraquinone. Nine crystallographically independent molecules were characterized by X-ray crystallography and Hirshfeld surfaces were derived from the X-ray structures. The space groups and number of independent molecules (Z′) for each of the polymorphs (1-5) is as follows: (1) P4 1 (or P4 3 ), Z′ ) 1; (2) Pca2 1 , Z′ ) 2; (3) P1 j , Z′ ) 4; (4) P2 1 /n, Z′ ) 1; (5) P4 1 2 1 2 (or P4 3 2 1 2), Z′ ) 0.5. Form 1 is the most thermodynamically stable among the reproducible structures, as established by competitive solubility tests, followed by 2 and then 4. The unrestrained structures of the five polymorphs were computed using the CVFF and COMPASS force fields as well as with the density functional code, SIESTA.

Structural and Hirshfeld Surface Analyses of a Novel Hetero-Tetranuclear CuII-NaI Bis(Salamo)-Based Coordination Compound

“…The Hirshfeld surfaces [86] of the coordination compound 1 are illustrated in Figure 6, indicating that the surfaces have been mapped over d norm and the corresponding location in shape index exists the complementary region of red concave surface surrounded by receptors and the blue convex surface surrounding receptors, further proving that such hydrogen bonding exists. The large and deep red spots on the three-dimensional (3D) Hirshfeld surfaces indicate the close-contact interactions, mainly responsible for the corresponding hydrogen bond contacts.…”

A polynuclear and two dinuclear copper(II) Schiff base complexes: Synthesis, characterization, self-assembly, magnetic property and DFT study

“…Hirshfeld surfaces [71][72][73] and the associated 2D-fingerprint [74][75][76] Waals separation, and blue regions were devoid of close contacts. For a given crystal structure and set of spherical atomic electron densities, the Hirshfeld surface was unique [78] and it was this property that suggested the possibility of gaining additional insight into the intermolecular interaction of molecular crystals.…”

Analysis of supramolecular interactions in alendroniate alkali metal salts: synthesis, structure, and properties of novel sodium alendronate polymorph

“…The size and shape of Hirshfeld surface characterize the interactions between atoms in a crystal, and hence reflect different intermolecular interactions [19][20][21][22][23]. The normalized contact distance, d norm , is a ratio including the distances of any surface point to the nearest nucleus internal to the surface, d i , and the nearest nucleus external to the surface, d e , and the van der Waals radii of the atoms, r vdW , presented by equation.…”

“…Noteworthy, there is a high variability of coordination spheres in all analyzed crystals. Furthermore, the HS study [19][20][21][22][23] was employed to gain insight into intermolecular interactions responsible for crystal packing. Additional features for new anhydrous sodium alendronate polymorph were revealed by powder X-ray diffraction (PXRD), differential scanning calor i m e t r y ( D S C ) , t h e r m o g r a v i m e t r y / d e r i v a t i v e thermogravimetry (TG/DTG), and Fourier transform infrared spectroscopy (FT-IR).…”