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.

Directing the Assembly of Molecular Crystals

MRS Bulletin ◽  
2005 ◽  
Vol 30 (10) ◽  
pp. 705-712 ◽  
Author(s):  
Michael D. Ward
Keyword(s):  
Crystal Structure ◽  
Molecular Crystals ◽  
Computational Prediction ◽  
State Structure ◽  
Crystalline Materials ◽  
Current State ◽  
The Individual ◽  
Crystal Design ◽  
Molecular Components ◽  
Selection Of

AbstractCrystalline materials made from molecular components can possess useful properties that can be tailored through judicious selection of their molecular building blocks.The utility of these materials, however, depends on molecular packing in the crystal lattice as well as the properties of the individual molecules themselves. Consequently, further advances hinge on our ability to manipulate solid-state structure in a rational and systematic manner. Although computational prediction of crystal structure remains elusive, empirical guidelines for assembling molecules into preordained crystal architectures are emerging rapidly. This article briefly describes the current state of the field, emphasizing the design of crystalline materials with structures reinforced by a twodimensional hydrogen-bonded network, which serves as a platform for the synthesis of a diverse collection of compounds. These include host frameworks with cavities supported by organic “pillars” that can be interchanged to manipulate the size, shape, and character of the inclusion cavities as well as the overall lattice architecture and metrics. This research has revealed some principles for crystal design that may prove useful in general while enabling exploration of the utility of these compounds.

Hybrid Organic/Inorganic Magnets

MRS Bulletin ◽  
2000 ◽  
Vol 25 (11) ◽  
pp. 52-57 ◽  
Author(s):  
Kunio Awaga ◽  
Eugenio Coronado ◽  
Marc Drillon
Keyword(s):  
Molecular Electronics ◽  
Electronic Conductivity ◽  
Hybrid Approach ◽  
Magnetic Layer ◽  
Building Blocks ◽  
Molecular Networks ◽  
Molecular Materials ◽  
Hybrid Compound ◽  
The Individual ◽  
Molecular Components

The construction of more and more complex systems starting from elemental molecular units used as building blocks is propelling several disciplines of burgeoning interest, such as supramolecular chemistry, molecular electronics, and molecular magnetism. In the particular context of magnetic molecular materials, an attractive possibility for adding complexity to the material is to use a hybrid approach in which an organic component is combined with an inorganic one. Both purely organic and purely inorganic approaches (see the articles in this issue by Veciana and Iwamura and by Miller, respectively) have been used extensively to obtain molecule-based magnets. The combination of these two kinds of magnetic molecular components has also been successfully explored to design polymeric magnets of different dimensionalities (the metal-radical approach). In this last case, both components play a magnetic role. A step forward in achieving multifunctionality is to design hybrid molecular materials formed by two independent molecular networks, such as anion/cation salts or host/guest solids, whereby each network furnishes distinct physical properties to the solid. This novel class of materials is interesting because it can give rise to the development of materials in which two properties in the same crystal lattice coexist, or materials that exhibit improved properties over those of the individual networks, or to new, unexpected properties due to the mutual interactions between them. One can imagine, for example, the combination of an extended inorganic magnetic layer opening the pathway to cooperative magnetism, with an organic or organometallic molecule that acts as a structural component controlling the interlayer separation. If the molecule inserted between the layers has unpaired electrons, a hybrid compound is produced that combines cooperative magnetism and paramagnetism. Other suitable combinations, such as electronic conductivity and magnetism, or nonlinear optics and magnetism, can also be achieved by wisely choosing the constituent molecules. In this article, we report some relevant examples that illustrate the potential of this hybrid approach in the context of molecule-based magnetic materials.

scholarly journals Oak Species Quercus robur L. and Quercus petraea Liebl. Identification Based on UHPLC-HRMS/MS Molecular Networks

Metabolites ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 684
Author(s):  
Gaëlle Buche ◽  
Cyril Colas ◽  
Laëtitia Fougère ◽  
Emilie Destandau
Keyword(s):  
Quercus Robur ◽  
Quercus Petraea ◽  
Molecular Network ◽  
Molecular Networks ◽  
Venn Diagram ◽  
Pedunculate Oak ◽  
Pure Species ◽  
Wide Range ◽  
Fragmentation Patterns ◽  
The Individual

Two species of oak are dominant in French forests: pedunculate oak (Quercus robur L.) and sessile oak (Quercus petraea Liebl.). Their differentiation is not straightforward but is essential to better understand their respective molecular content in order to better valorize them. Thus, to improve oak species identification, an untargeted UHPLC-HRMS/MS method associated with a two-step data treatment was developed to analyze a wide range of specialized metabolites enabling the comparison of both species of oak extracts. Pooled extracts from sessile and pedunculate oaks, composed of extracts from several trees of pure species from various origins, were compared using first the Venn diagram, as a quick way to get an initial idea of how close the extracts are, and then using a molecular network to visualize, on the one hand, the ions shared between the two species and, on the other hand, the compounds specific to one species. The molecular network showed that the two species shared common clusters mainly representative of tannins derivatives and that each species has specific molecules with similar fragmentation patterns, associated in specific clusters. This methodology was then applied to compare these two pooled extracts to unknown individuals in order to determine the species. The Venn diagram allowed for the quick presumption of the species of the individual and then the species could be assigned more precisely with the molecular network, at the level of specific clusters. This method, developed for the first time, has several interests. First, it makes it possible to discriminate the species and to correctly assign the species of unknown samples. Moreover, it gave an overview of the metabolite composition of each sample to better target oak tree utilization and valorization.

scholarly journals Applications of molecular networks in biomedicine

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Monica Chagoyen ◽  
Juan A G Ranea ◽  
Florencio Pazos
Keyword(s):  
Single Gene ◽  
Point Of View ◽  
Molecular Networks ◽  
Large Sets ◽  
Software Packages ◽  
Number Of Genes ◽  
Complex Phenomena ◽  
Network Approaches ◽  
Molecular Components ◽  
Standard Software

Abstract Due to the large interdependence between the molecular components of living systems, many phenomena, including those related to pathologies, cannot be explained in terms of a single gene or a small number of genes. Molecular networks, representing different types of relationships between molecular entities, embody these large sets of interdependences in a framework that allow their mining from a systemic point of view to obtain information. These networks, often generated from high-throughput omics datasets, are used to study the complex phenomena of human pathologies from a systemic point of view. Complementing the reductionist approach of molecular biology, based on the detailed study of a small number of genes, systemic approaches to human diseases consider that these are better reflected in large and intricate networks of relationships between genes. These networks, and not the single genes, provide both better markers for diagnosing diseases and targets for treating them. Network approaches are being used to gain insight into the molecular basis of complex diseases and interpret the large datasets associated with them, such as genomic variants. Network formalism is also suitable for integrating large, heterogeneous and multilevel datasets associated with diseases from the molecular level to organismal and epidemiological scales. Many of these approaches are available to nonexpert users through standard software packages.

Crystal Engineering for Intramolecular π–π Stacking: Effect of Sequential Substitution of F on Molecular Geometry in Conformationally Flexible Sulfonamides

2019 ◽  
Vol 19 (10) ◽  
pp. 5665-5678 ◽  
Author(s):  
Samir R. Shaikh ◽  
Rupesh L. Gawade ◽  
Deepak Kumar ◽  
Amol Kotmale ◽  
Rajesh G. Gonnade ◽  
...  
Keyword(s):  
Crystal Engineering ◽  
Molecular Geometry ◽  
Π Stacking ◽  
Stacking Effect

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.

Controlled gas nitriding of the surfaces of blind holes using the two-component NH3+NH3diss atmospheres during the heating-up stage

2018 ◽  
Vol 23 (1) ◽  
pp. 27-31
Author(s):  
Jan Bujak ◽  
Paweł Hermanowicz
Keyword(s):  
Chemical Composition ◽  
Nitrided Layer ◽  
High Hardness ◽  
Iron Nitrides ◽  
Structure And Properties ◽  
Gas Nitriding ◽  
Structures And Properties ◽  
Two Component ◽  
Preliminary Research ◽  
Heating Up

The paper presents the preliminary research results of the influence of the chemical composition of the two-component nitriding atmospheres on the structure and properties of the nitrided layers in the surfaces of the blind holes. The results showed that the utilization during the heating-up stage of in the controlled gas nitriding process the two-component atmospheres NH3 + NH3diss enables the production of the nitrided layers with a limited thickness of an iron nitrides layer as well as and a sufficiently high hardness on the surfaces of the blind holes. The nitrided layers obtained on the surfaces of the blind holes, depending on the position in the hole, show similar differentiation of the structures and properties, regardless of the dilution rate of ammonia in the atmospheres that were used during the heating-up stage. This differentiation is caused by the weak inflow of the fresh nitriding atmosphere to the interior of the blind holes due to their small diameters, which in turn is manifested as a gradual slowdown of the growth kinetics, a reduction of the thickness and hardness of a nitrided layer along with the increase in the depth of the blind holes.

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