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

2017 ◽  
Vol 203 ◽  
pp. 93-112 ◽  
Author(s):  
Alison J. Edwards ◽  
Campbell F. Mackenzie ◽  
Peter R. Spackman ◽  
Dylan Jayatilaka ◽  
Mark A. Spackman
Keyword(s):  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Crystal Engineering ◽  
Molecular Electrostatic Potential ◽  
Molecular Crystals ◽  
Interaction Energies ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Crystal Properties ◽  
Tetrel Bonds

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.

scholarly journals Direct evidence for 2-fold to 3-fold change of interpenetration in a MOF

2014 ◽  
Vol 70 (a1) ◽  
pp. C636-C636
Author(s):  
Himanshu Aggarwal ◽  
Prashant Bhatt ◽  
Charl Benzuidenhout ◽  
Leonard Barbour
Keyword(s):  
Single Crystal ◽  
Crystal Engineering ◽  
Molecular Level ◽  
Metal Organic Framework ◽  
Structural Rearrangement ◽  
Structure Property ◽  
Ambient Conditions ◽  
Physical Conditions ◽  
Structure Property Relationships ◽  
Metal Organic

Single-crystal to single-crystal transformations has recently received much attention in the field of crystal engineering. Such transformations not only provide insight into the changes taking place within the crystal at the molecular level, but they also aid our understanding of the structure-property relationships. Discrete crystals have been shown to tolerate considerable dynamic behavior at the molecular level while maintaining their single-crystal character. Examples that are common in the literature include bond formation/cleavage,[1] guest uptake,[2] release or exchange as well as polymorphic phase transformations. However, there are rare examples of the structural transformations on the host framework initiated by removal of guest or change in physical conditions such as temperature or pressure. We have investigated a known doubly-interpenetrated metal organic framework with the formula [Zn2(ndc)2(bpy)] which possesses minimal porosity when activated. We have shown not only that the material converts to its triply-interpenetrated analogue upon desolvation, but that the transformation occurs in a single-crystal to single-crystal manner under ambient conditions.[3] This contribution probes the limits to which a single-crystal material can undergo structural rearrangement while still maintaining the macroscopic integrity of the crystal as a discrete entity.

Directional Weak Intermolecular Interactions: σ-Hole Bonding

2010 ◽  
Vol 63 (12) ◽  
pp. 1598 ◽  
Author(s):  
Jane S. Murray ◽  
Kevin E. Riley ◽  
Peter Politzer ◽  
Timothy Clark
Keyword(s):  
Hydrogen Bonding ◽  
Intermolecular Interactions ◽  
Electrostatic Potential ◽  
Crystal Engineering ◽  
Molecular Electrostatic Potential ◽  
Weak Interactions ◽  
Halogen Bonding ◽  
Donor Atom ◽  
Weak Intermolecular Interactions ◽  
Special Case

The prototypical directional weak interactions, hydrogen bonding and σ-hole bonding (including the special case of halogen bonding) are reviewed in a united picture that depends on the anisotropic nature of the molecular electrostatic potential around the donor atom. Qualitative descriptions of the effects that lead to these anisotropic distributions are given and examples of the importance of σ-hole bonding in crystal engineering and biological systems are discussed.

Associations of squaric acid and its anions as multiform building blocks of hydrogen-bonded molecular crystals

2001 ◽  
Vol 57 (6) ◽  
pp. 859-865 ◽  
Author(s):  
Gastone Gilli ◽  
Valerio Bertolasi ◽  
Paola Gilli ◽  
Valeria Ferretti
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Engineering ◽  
Negative Charge ◽  
Three Dimensional ◽  
Molecular Crystals ◽  
Building Blocks ◽  
Squaric Acid ◽  
Orthosilicic Acid ◽  
Molecular Plane ◽  
Dimensional Crystal

Squaric acid, H2C4O4 (H2SQ), is a completely flat diprotic acid that can crystallize as such, as well as in three different anionic forms, i.e. H2SQ·HSQ−, HSQ− and SQ2−. Its interest for crystal engineering studies arises from three notable factors: (i) its ability of donating and accepting hydrogen bonds strictly confined to the molecular plane; (ii) the remarkable strength of the O—H...O bonds it may form with itself which are either of resonance-assisted (RAHB) or negative-charge-assisted [(−)CAHB] types; (iii) the ease with which it may donate a proton to an aromatic base which, in turn, back-links to the anion by strong low-barrier N—H+...O1/2− charge-assisted hydrogen bonds. Analysis of all the structures so far known shows that, while H2SQ can only crystallize in an extended RAHB-linked planar arrangement and SQ2− tends to behave much as a monomeric dianion, the monoanion HSQ− displays a number of different supramolecular patterns that are classifiable as β-chains, α-chains, α-dimers and α-tetramers. Partial protonation of these motifs leads to H2SQ·HSQ− anions whose supramolecular patterns include ribbons of dimerized β-chains and chains of emiprotonated α-dimers. The topological similarities between the three-dimensional crystal chemistry of orthosilicic acid, H4SiO4, and the two-dimensional one of squaric acid, H2C4O4, are finally stressed.

Bases, solvates and salts: new benzimidazole- and pyridine-scaffolded ligands

2020 ◽  
Vol 76 (4) ◽  
pp. 367-374
Author(s):  
Aleksandra Bocian ◽  
Adam Gorczyński ◽  
Dawid Marcinkowski ◽  
Grzegorz Dutkiewicz ◽  
Violetta Patroniak ◽  
...  
Keyword(s):  
Schiff Base ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Stabilization Energy ◽  
Interaction Energies ◽  
Free Base ◽  
Schiff Base Ligands ◽  
Π Interactions ◽  
Charged Ligands

The intermolecular interactions in the structures of a series of Schiff base ligands have been thoroughly studied. These ligands can be obtained in different forms, namely, as the free base 2-[(2E)-2-(1H-imidazol-4-ylmethylidene)-1-methylhydrazinyl]pyridine, C10H11N5, 1, the hydrates 2-[(2E)-2-(1H-imidazol-2-ylmethylidene)-1-methylhydrazinyl]-1H-benzimidazole monohydrate, C12H12N6·H2O, 2, and 2-{(2E)-1-methyl-2-[(1-methyl-1H-imidazol-2-yl)methylidene]hydrazinyl}-1H-benzimidazole 1.25-hydrate, C13H14N6·1.25H2O, 3, the monocationic hydrate 5-{(1E)-[2-(1H-1,3-benzodiazol-2-yl)-2-methylhydrazinylidene]methyl}-1H-imidazol-3-ium trifluoromethanesulfonate monohydrate, C12H13N6 +·CF3O3S−·H2O, 5, and the dicationic 2-{(2E)-1-methyl-2-[(1H-imidazol-3-ium-2-yl)methylidene]hydrazinyl}pyridinium bis(trifluoromethanesulfonate), C10H13N5 2+·2CF3O3S−, 6. The connection between the forms and the preferred intermolecular interactions is described and further studied by means of the calculation of the interaction energies between the neutral and charged components of the crystal structures. These studies show that, in general, the most important contribution to the stabilization energy of the crystal is provided by π–π interactions, especially between charged ligands, while the details of the crystal architecture are influenced by directional interactions, especially relatively strong hydrogen bonds. In one of the structures, a very interesting example of the nontypical F...O interaction was found and its length, 2.859 (2) Å, is one of the shortest ever reported.

Self-trapping DCM by the host deformation in flexible host-guest molecules

CrystEngComm ◽  
2021 ◽  
Author(s):  
Le-Ping Miao ◽  
Qi Qi ◽  
Xiang-Bin Han ◽  
Wen Zhang
Keyword(s):  
Intermolecular Interactions ◽  
Crystal Engineering ◽  
Molecular Crystals ◽  
Fluorescent Sensors ◽  
Classical Type ◽  
Molecular Materials ◽  
Guest Molecules ◽  
Self Trapping

Host-guest molecular crystals are a classical type of molecular materials widely applied for fluorescent sensors, absorption, separation, etc. Their significance is deciphering intermolecular interactions in crystal engineering and expanding the...

scholarly journals Structure–property relationships in protic ionic liquids: a thermochemical study

2017 ◽  
Vol 19 (30) ◽  
pp. 19928-19936 ◽  
Author(s):  
Joshua E. S. J. Reid ◽  
Filipe Agapito ◽  
Carlos E. S. Bernardes ◽  
Filomena Martins ◽  
Adam J. Walker ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Intermolecular Interactions ◽  
Fundamental Question ◽  
Thermochemical Study ◽  
Structure Property ◽  
Protic Ionic Liquids ◽  
Structure Property Relationships ◽  
Invaluable Tool

How does cation functionality influence the strength of intermolecular interactions in protic ionic liquids (PILs)? Quantifying the energetics of PILs can be an invaluable tool to answer this fundamental question.

New Second-Order Nonlinear Optical Organic Crystals

1989 ◽  
Vol 173 ◽  
Author(s):  
D.S. Donald ◽  
L.-T. Cheng ◽  
G. Desiraju ◽  
G. R. Meredith ◽  
F. C. Zumsteg
Keyword(s):  
Nonlinear Optical ◽  
Near Infrared ◽  
Crystal Packing ◽  
Screening Program ◽  
Molecular Crystals ◽  
Molecular Properties ◽  
Organic Crystals ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Near Ultraviolet

ABSTRACTThe design of molecular crystals with specific optical properties, which are thought to arise from constituent molecules’ polarizability properties, is a desirable but currently unachievable goal. One can partially achieve this goal by choosing compounds with specific molecular attributes and empirically determining the manner in which these are translated into crystal properties. Besides the fact that there are no certain rules for prediction of crystal packing arrangements, there is also a problem in specifying molecular properties from what are today incomplete polarizability structure-property relationships. We have, realizing these limitations, identified new molecular crystals by a nonlinear optical (powder-SHG) scouting-screening program from lists of compounds chosen because of desirable molecular properties. Examination of successful materials has revealed interesting, new alignment motifs. Some of these materials, a set of halogen and cyano derivatives of aromatic compounds, are described relating properties and structures of molecules and crystals. In particular, the orientation directing influence of intermolecular halogen-cyano interactions and the use of heterocyclic compounds to improve transparency in the near infrared and in the blue and near ultraviolet spectral regions are demonstrated.

scholarly journals Hierarchical model of molecular crystals

2014 ◽  
Vol 70 (a1) ◽  
pp. C549-C549
Author(s):  
Izabela Madura
Keyword(s):  
Intermolecular Interactions ◽  
Crystal Engineering ◽  
3D Structure ◽  
Molecular Crystals ◽  
Spatial Arrangement ◽  
Close Packing ◽  
Hierarchical Organization ◽  
Van Der Waals Interactions ◽  
Hierarchical Architecture ◽  
Identification Analysis

Spatial arrangement of molecules in molecular crystals depends on properties of molecules building up the crystal, and in particular on the nature of interactions occurring between them. The knowledge about primary and subsequent interactions building up the 3D structure seems to be important in many aspects, just to mention crystal engineering and crystallization processes. If the only interactions between molecules are isotropic van der Waals interactions, the observed structure will resemble a close-packing arrangement. The presence of any directional interactions leads, in accordance to Kitaigorodsky's principles,[1] to the symmetry breaking of the close-packing structure, and resulting crystal exhibits hierarchical organization. The presentation will discuss consequences of directional intermolecular interactions and their impact on generation and organization of successive levels of the hierarchical architecture in crystals. The strategy for identification, analysis and hierarchization of weak intermolecular interactions will also be presented. Selected examples will serve to illustrate usefulness of the proposed model for the discussion on molecular symmetry, supramolecular synthons' equivalency, polymorphism, isomorphism or packing.

scholarly journals Synthesis, liquid crystalline behaviour and structure–property relationships of 1,3-bis(5-substituted-1,3,4-oxadiazol-2-yl)benzenes

2020 ◽  
Vol 16 ◽  
pp. 149-158
Author(s):  
Afef Mabrouki ◽  
Malek Fouzai ◽  
Armand Soldera ◽  
Abdelkader Kriaa ◽  
Ahmed Hedhli
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystalline ◽  
Dipole Moments ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rigid Core ◽  
X Ray ◽  
Structure Property Relationships ◽  
Crystal Properties

Two series containing 1,3-bis(1,3,4-oxadiazol-2-yl)benzene as a rigid core (RC) and alkyl or perfluoroalkyl as terminal chains were synthesized and characterized. Liquid crystal properties of the synthesized compounds have been investigated by polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction techniques. Conformation effects of the synthesized products on the dipole moments were also investigated.

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