Intra-Solid and Inter-Solid Reactions of Molecular Crystals: a Green Route to Crystal Engineering

2005 ◽  
pp. 71-94 ◽  
Author(s):  
Dario Braga ◽  
Daniela D’Addario ◽  
Stefano L. Giaffreda ◽  
Lucia Maini ◽  
Marco Polito ◽  
...  
Keyword(s):  
Crystal Engineering ◽  
Molecular Crystals ◽  
Green Route

Midway between Energetic Molecular Crystals and High-Density Energetic Salts: Crystal Engineering with Hydrogen Bonded Chains of Polynitro Bipyrazoles

2020 ◽  
Vol 20 (2) ◽  
pp. 755-764 ◽  
Author(s):  
Ivan Gospodinov ◽  
Kostiantyn V. Domasevitch ◽  
Cornelia C. Unger ◽  
Thomas M. Klapötke ◽  
Jörg Stierstorfer
Keyword(s):  
Crystal Engineering ◽  
Molecular Crystals ◽  
High Density ◽  
Energetic Salts ◽  
Hydrogen Bonded

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.

scholarly journals Origin and structure of polar domains in doped molecular crystals

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
E. Meirzadeh ◽  
I. Azuri ◽  
Y. Qi ◽  
D. Ehre ◽  
A. M. Rappe ◽  
...  
Keyword(s):  
Crystal Engineering ◽  
Density Functional ◽  
Molecular Crystals ◽  
Strong Support ◽  
Functional Theory ◽  
Guest Molecules ◽  
Molecular Dynamics Calculations ◽  
Different Temperatures ◽  
Global Understanding

Abstract Doping is a primary tool for the modification of the properties of materials. Occlusion of guest molecules in crystals generally reduces their symmetry by the creation of polar domains, which engender polarization and pyroelectricity in the doped crystals. Here we describe a molecular-level determination of the structure of such polar domains, as created by low dopant concentrations (<0.5%). The approach comprises crystal engineering and pyroelectric measurements, together with dispersion-corrected density functional theory and classical molecular dynamics calculations of the doped crystals, using neutron diffraction data of the host at different temperatures. This approach is illustrated using centrosymmetric α-glycine crystals doped with minute amounts of different L-amino acids. The experimentally determined pyroelectric coefficients are explained by the structure and polarization calculations, thus providing strong support for the local and global understanding of how different dopants influence the properties of molecular crystals.

scholarly journals Plasticity in zwitterionic drugs: the bending properties of Pregabalin and Gabapentin and their hydrates

IUCrJ ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 630-634 ◽  
Author(s):  
U. B. Rao Khandavilli ◽  
Matteo Lusi ◽  
Patrick J. Frawley
Keyword(s):  
Mechanical Properties ◽  
Crystal Engineering ◽  
Weak Interactions ◽  
Molecular Crystals ◽  
Structural Features ◽  
Microscopic Structure ◽  
Bending Properties ◽  
Crystalline Materials ◽  
Area Of Interest ◽  
Macroscopic Plasticity

The investigation of mechanical properties in molecular crystals is emerging as a novel area of interest in crystal engineering. Indeed, good mechanical properties are required to manufacture pharmaceutical and technologically relevant substances into usable products. In such endeavour, bendable single crystals help to correlate microscopic structure to macroscopic properties for potential design. The hydrate forms of two anticonvulsant zwitterionic drugs, Pregabalin and Gabapentin, are two examples of crystalline materials that show macroscopic plasticity. The direct comparison of these structures with those of their anhydrous counterparts, which are brittle, suggests that the presence of water is critical for plasticity. In contrast, structural features such as molecular packing and anisotropic distribution of strong and weak interactions seem less important.

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...

Hydrogen-bonded assemblies in the molecular crystals of 2,2′-thiodiacetic acid with ethylenediamine ando-phenylenediamine

2017 ◽  
Vol 73 (2) ◽  
pp. 97-103 ◽  
Author(s):  
V. Gomathi ◽  
C. Theivarasu
Keyword(s):  
Crystal Engineering ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
Molecular Crystals ◽  
Charge Transfer Complexes ◽  
Supramolecular Network ◽  
One Dimensional ◽  
Supramolecular Networks ◽  
Supramolecular Chains ◽  
Hydrogen Bonded

Carboxylate molecular crystals have been of interest due to the presence of hydrogen bonding, which plays a significant role in chemical and crystal engineering, as well as in supramolecular chemistry. Acid–base adducts possess hydrogen bonds which increase the thermal and mechanical stability of the crystal. 2,2′-Thiodiacetic acid (Tda) is a versatile ligand that has been widely explored, employing its multidendate and chelating coordination abilities with many metals; however, charge-transfer complexes of thiodiacetic acid have not been reported. Two salts, namely ethylenediaminium 2,2′-thiodiacetate, C2H10N22+·C4H4O4S22−, denoted Tdaen, and 2-aminoanilinium 2-(carboxymethylsulfanyl)acetate, C6H9N2+·C4H5O4S−, denoted Tdaophen, were synthesized and characterized by IR,1H and13C NMR spectroscopies, and single-crystal X-ray diffraction. In these salts, Tda reacts with the aliphatic (ethylenediamine) and aromatic (o-phenylenediamine) diamines, and deprotonates them to form anions with different valencies and different supramolecular networks. In Tdaen, the divalent Tda2−anions form one-dimensional linear supramolecular chains and these are extended into a three-dimensional sandwich-type supramolecular network by interaction with the ethylenediaminium cations. However, in Tdaophen, the monovalent Tda−anions form one-dimensional zigzag supramolecular chains, which are extended into a three-dimensional supramolecular network by interaction with the 2-aminoanilinium cations. Thus, both three-dimensional structures display different ring motifs. The structures of these diamines, which are influenced by hydrogen-bonded assemblies in the molecular crystals, are discussed in detail.

Engineering crystals built from molecules containing boron

2006 ◽  
Vol 78 (7) ◽  
pp. 1305-1321 ◽  
Author(s):  
Kenneth E. Maly ◽  
Nadia Malek ◽  
Jean-Hugues Fournier ◽  
Patricia Rodríguez-Cuamatzi ◽  
Thierry Maris ◽  
...  
Keyword(s):  
Crystal Engineering ◽  
Molecular Crystals ◽  
Molecular Geometry ◽  
Molecular Networks ◽  
Structure And Properties ◽  
Structures And Properties ◽  
Structural Preferences ◽  
Direct Association ◽  
The Individual ◽  
Molecular Components

The study of compounds containing boron continues to have an important impact on virtually every area of chemistry. One of the few areas in which compounds of boron have been neglected is crystal engineering, which seeks to develop and exploit an understanding of how the structure and properties of crystals are related to the individual atomic or molecular components. Although detailed predictions of crystal structures are not yet reliable, crystal engineers have developed a sound qualitative strategy for anticipating and controlling structural preferences. This strategy is based on the design of special molecules, called tectons, which feature carefully selected cores and multiple peripheral functional groups that can direct association and thereby place neighboring molecules in predetermined positions. Recent work has demonstrated that molecular crystals with unique properties can be constructed logically from tectons with boron in their cores or sticky sites of association. In particular, the -B(OH)2 group of boronic acids engages in reliable patterns of hydrogen bonding, and its use as a sticky site in tectons has emerged as an effective tool for controlling association predictably. In addition, replacement of tetraphenylsilyl or tetraphenylmethyl cores in tectons by tetraphenylborate leaves the overall molecular geometry little changed, but it has the profound effect of introducing charge. Tectons derived from tetraphenylborate can be used rationally to construct porous charged molecular networks that resemble zeolites and undergo selective ion exchange. In such ways, boron offers chemists exciting new ways to engineer molecular crystals with predetermined structures and properties.

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.

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