Intermolecular interactions in molecular crystals: what’s in a name?

Abstract

Structure-property relationships are the key to modern crystal engineering, and for molecular crystals this requires both a thorough understanding of intermolecular interactions, and the subsequent use of this to create solids with desired properties. There has been a rapid increase in publications aimed at furthering this understanding, especially the importance of non-canonical interactions such as halogen, chalcogen, pnicogen, and tetrel bonds. Here we show how all of these interactions - and hydrogen bonds - can be readily understood through their common origin in the redistribution of electron density that results from chemical bonding. This redistribution is directly linked to the molecular electrostatic potential, to qualitative concepts such as electrostatic complementarity, and to the calculation of quantitative intermolecular interaction energies. Visualization of these energies, along with their electrostatic and dispersion components, sheds light on the architecture of molecular crystals, in turn providing a link to actual crystal properties.

Crystal Structure and Computational Study on Methyl-3-Aminothiophene-2-Carboxylate

“…The percentage contributions of each interaction to the Hirshfeld surface are depicted in Figure 4. In order to understand the nature of the intermolecular interaction, energy-framework computational analysis can be used to quantitatively characterize the calculated interaction energy between the molecular pairs in molecular crystals [33,34]. The total interaction energy was calculated by generating the molecular cluster of radius 3.8 Å around the selected three different molecules in the asymmetric unit.…”

Molecular Structure, DFT, Vibrational Spectra with Fluorescence Effect, Hirshfeld Surface, Docking Simulation and Antioxidant Activity of Thiazole Derivative

“…CrystalExplorer17.5 has been adopted to calculate and visualize the energy frameworks of the molecular system by using B3LYP function under 6–31G (d,p) bases set level. This technique provides us deep information about the type of energies responsible for supramolecular architecture of crystal packing in the molecular system, by analyzing the nature of different types of interactions between the molecular pairs such as dispersion, electrostatic, repulsion, and polarization (see Table 9 in supporting information (SI)) . The molecular environment has been constructed by taking one molecule at its center and around with the maximum distance of 3.8 Å.…”

“…The molecular environment has been constructed by taking one molecule at its center and around with the maximum distance of 3.8 Å. The benchmarked energies used to construct the energy framework in the calculation were scaled according to Mackenzie et al While the scale factors of others energies are 1.057, 0.740, 0.871 and 0.618 for electrostatic, dispersion, polarization, and repulsion interactions, respectively . In Figure the cylinders indicate the relative strengths in energy framework of molecular packing in all directions.…”

SBA15–Fluconazole as a Protective Approach Against Mild Steel Corrosion: Synthesis, Characterization, and Computational Studies

“…These interactions were classified into two groups: F⋅⋅⋅O, O⋅⋅⋅O, N⋅⋅⋅⋅O, and C⋅⋅⋅O, belonging to non‐canonical weak interactions; and O−H⋅⋅⋅O, O−H⋅⋅⋅N, and O−H⋅⋅⋅F, categorized as hydrogen bonds. Although it is not clear that the four contacts of the former group could be in the bond categories of halogen, chalcogen, pnicogen, or tetrel, which have been explained mainly in electrostatic terms because of the presence of sigma holes, it is recognized that these contribute to the stability of molecular clusters and crystals and, therefore, must have an attractive nature. C−H⋅⋅⋅O can be considered a hydrogen bond, albeit a weaker and non‐classical type .…”

“…These interactions were classified into two groups:F ···O, O···O, N····O, and C···O, belonging to non-canonical weaki nteractions;a nd OÀH···O, OÀH···N, and OÀH···F,c ategorized as hydrogen bonds. Althoughi ti sn ot clear that the four contacts of the former group could be in the bond categories of halogen, chalcogen, pnicogen, or tetrel, [65][66][67][68][69][70][71][72][73] which have been explained mainly in electrostatic terms because of the presence of sigma holes, [74] it is recognized that thesec ontributet ot he stabilityo fm olecular clusters andc rystalsa nd, therefore, must have an attractive nature.C ÀH···O can be considered ah ydrogen bond, [72] albeit aw eaker and non-classical type. [75] For both groups of interactions, low values of the electron density were searched, with the Laplacian (positive in each case) and the virial field at the bond critical points (BCPs).…”