Characterization of Halogen Bonds with Multinuclear Magnetic Resonance in the Solid-State, X-ray Crystallography, and Quantum Chemical Calculations PDF Download

Author: Jasmine Viger-Gravel
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ISBN:
Category :
Languages : en
Pages :

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Author: Patrick Szell
Publisher:
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Category :
Languages : en
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The halogen bond has recently risen in prominence as a non-covalent interaction for use in supramolecular chemistry, allowing for the rational design of materials, pharmaceuticals, and functional molecules. The occurrence of the ?-hole opposite to the C-X covalent bond (X = F, Cl, Br, I) renders the halogen bond a highly directional and tuneable interaction, offering desirable features to crystal engineers. The halogen bond can be divided into its two components: the halogen bond donor bearing the halogen atom, and the electron-rich halogen bond acceptor. In this thesis, we investigate the nature of the halogen bond, its role in supramolecular assembly and impact on the local dynamics, along with developing synthetic methods to prepare this class of materials. We begin by fully characterizing the halogen bond donor by using 35Cl ultra-wideline solid-state nuclear magnetic resonance (NMR) spectroscopy on a series of single-component chloronitriles exhibiting the C-Cl···N halogen bond. We then perform the first modern nuclear quadrupole resonance (NQR) investigations of the halogen bond, observing the 79/81Br and 127I nuclei in a series of cocrystals exhibiting the C-Br···N and C-I···N halogen bond, respectively. Computational results attribute the observed increases in the quadrupolar coupling constants (CQ) to a reduction in the carbon-halogen ?-bonding contribution to V33 and an increase in the lone-pair and core orbital contributions, providing the first model of the electronic changes occurring on the halogen bond donor upon the formation of the halogen bond. Attention is then turned on characterizing the halogen bond acceptor and its surrounding environment, beginning by investigating a solid-state NMR approach relying on the 19F nucleus to characterize perfluorinated cocrystals. This strategy has reduced analysis times from hours to minutes while providing higher sensitivity and resolution, with the resulting chemical shifts permitting the unambiguous identification of the halogen bond and allowing for the refinement of X-ray crystal structures. The halogen bond acceptor is then investigated in a series of isomorphous dimers exhibiting both the halogen bond and hydrogen bond in the C≡C-I···X-···H-N+ motif, revealing the halogen bond's relative contribution to the electric field gradient increasing in the order of Cl- > Br- > I-, contrasting the contributions of the hydrogen bond. We then explore the impact of the halogen bond on the surrounding environment, using the rotating methyl groups of 2,3,5,6-tetramethylpyrazine as a model. Upon the introduction of a halogen bond, we observe a reduction in the rotational energy barrier of 56% on average, overshadowing the 36% reduction observed in the hydrogen bonded cocrystals. This is the first instance of the halogen bond directly catalyzing the local dynamics, coining the term "dynamics catalyst". These results provide an effective strategy of enhancing the dynamics in molecular systems, such as molecular machines, supramolecular catalyst, as well as correcting the faulty dynamics encountered in diseased proteins. The role of halogen bonding in crystal engineering is then explored, reporting the first supramolecular triangle, a series of discrete charged dimers, and supramolecular architectures built from 1,3,5-tri(iodoethynyl)-2,4,6-trifluorobenzene, with the potential of creating fully organic porous structures for gas absorption. Mechanochemistry is then investigated as a synthetic method, allowing for the preparation of cocrystals featuring 3-iodoethynylbenzoic acid as the donor, with the resulting structures exhibiting concurrent halogen and hydrogen bonding. Mechanochemical ball milling is shown to reduce preparation times of powdered cocrystals from days to a single hour, while using a fraction of the organic solvent. Lastly, we pioneer cosublimation as a solvent-free synthetic technique for rapidly preparing halogen bonded cocrystals, yielding quality single crystals within a few hours, and a microcrystalline product within 15 minutes. Among its advantages, cosublimation offers a significant acceleration of discovery, while eliminating the environmental footprint associated with conventional synthetic methods.

Author: Yijue Xu
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Category :
Languages : en
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The nature and potential application of halogen bonding are currently topics of great interest among various research fields, including biochemistry, functional materials, organocatalysis, etc. Solid-state nuclear magnetic resonance (SSNMR) has been recognized as one of the important tools for characterizing different types of non-covalent interactions. This dissertation demonstrates how different SSNMR methods can be used to characterize the changes in electronic structure associated with halogen bonding interactions and investigates the processes leading to the formation of halogen bonds. A series of cocrystals featuring halogen bonds between phosphine oxides and different diiodoperfluorobenzenes (1,4-diiodotetrafluorobenzene, 1,2-diiodotetrafluorobenzene, and 1,3,5-trifluoro-2,4,6-triiodobenzene) have been synthesized through slow evaporation from solvent or by mechanochemistry. We began by characterizing the naturally abundant and 17O-labeled phosphine oxides and their halogen-bonded cocrystals by a combination of theoretical and experimental multinuclear magnetic resonance spectroscopy (31P and 17O), and X-ray diffraction (XRD) methods. This first study of 17O NMR parameters in halogen-bonded solids has provided key insights into the correlation between NMR observables and the nature of the halogen bond. Then a rare example of a cocrystal featuring a phosphine as a halogen bond acceptor was synthesized and characterized by both solution and solid-state NMR experiments, and the 31P NMR experiment acted as a direct probe for the formation of halogen bonds in both solution and solid states. In addition to the conventional polycrystalline solid-state NMR experiments, single-crystal NMR studies were performed on 17O labeled triphenylphosphine oxide and its halogen-bonded cocrystals with diiodoperfluorobenzenes, which allowed for the measurement of not only the magnitude but also the orientation of the NMR tensors. The work helped investigate the changes in NMR tensor orientation caused by the formation of halogen bonds and thereby provides a novel connection between the electronic structure and the NMR interactions. Novel single-crystal NMR analysis software was developed to fit the data in two ways: either through an unconstrained fitting process or through a constrained fitting process, which can improve the precision of the resulting tensor orientations in some cases. The mechanochemical production of halogen bonds inspired us to investigate the mechanism and kinetics behind this solid-state reaction process in situ. In situ 31P solid-state NMR studies of halogen bond formation between triphenylphosphine oxide and 1,4-diiodotetrafluorobenzene were carried out under different conditions (temperature, spinning speed, and different amounts of liquid added) to provide insight into the crystallization process and provide an estimation of the activation energy. Overall, this thesis provides several new applications of NMR spectroscopy to the study of halogen bonds and provides various novel insights into the connection between the NMR observables and the nature of this non-covalent interaction.

Author:
Publisher: Academic Press
ISBN: 0128023325
Category : Science
Languages : en
Pages : 311

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Nuclear magnetic resonance (NMR) is an analytical tool used by chemists and physicists to study the structure and dynamics of molecules. In recent years, no other technique has gained such significance as NMR spectroscopy. It is used in all branches of science in which precise structural determination is required and in which the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a premier means for the specialist and non-specialist alike to become familiar with new techniques and applications of NMR spectroscopy. - This volume of Annual Reports on NMR Spectroscopy focuses on the analytical tools used by chemists and physicists, taken together with other volumes of this series, an excellent account of progress in NMR and its many applications is provided and anyone using NMR will find interest in this Serial

Author: Anna V. Vologzhanina
Publisher: MDPI
ISBN: 3039361708
Category : Science
Languages : en
Pages : 144

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Unravelling an intricate network of interatomic interactions and their relations to different behaviors of chemical compounds is key to the successful design of new materials for both existing and novel applications, from medicine to innovative concepts of molecular electronics and spintronics. X-ray crystallography has proven to be very helpful in addressing many important chemical problems in modern materials science and biosciences. Intertwined with computational techniques, it provides insights into the nature of chemical bonding and the physicochemical properties (including optical, magnetic, electrical, mechanical, and others) of crystalline materials, otherwise accessible by experimental techniques that are not so readily available to chemists. In addition to the advanced approaches in charge density analysis made possible by X-ray diffraction, the information collected over the years through this technique (which is easily mined from huge databases) has tremendous use in the design of new materials for medicine, gas storage, and separation applications as well as for electronic devices. This Special Issue contains two reviews and five articles that cover very different aspects of ‘composition–structure’ and ‘structure–property’ relations identified by X-ray diffraction and complementary techniques (from conventional IR and Raman spectroscopies to cutting-edge quantum chemical calculations) and their use in crystal engineering and materials science.

Author: Pierangelo Metrangolo
Publisher: Springer
ISBN: 3319140574
Category : Science
Languages : en
Pages : 286

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The nature and directionality of halogen bonding; the sigma hole, by Timothy Clark, Peter Politzer, Jane S. Murray Solid-state NMR study of halogen-bonded adducts, by David Bryce Infrared and Raman measurements of halogen bonding in cryogenic solutions, by Wouter Herrebout Halogen bonding in the gas phase, by Anthony C. Legon Halogen bonding in solution, Mate Erdelyi Unconventional motifs for halogen bonding, by Kari Rissanen Halogen bonding in supramolecular synthesis, Christer Aakeröy Halogen bond in synthetic organic chemistry, Stefan M. Huber Anion recognition in solution via halogen bonding, Mark S. Taylor Anion transport with halogen bonds, by Stefan Matile Halogen bonding in silico drug design, by Pavel Hobza, Kevin Riley Biological halogen bonds: An old dog with new tricks, by P. Shing Ho Principles and applications of halogen bonding in medicinal chemistry, by Frank M. Boeckler Halogen bond in molecular conductors and magnets, by Marc Foumigué Halogen bonding towards design of organic phosphors, by Wei Jun Jin Halogen bond in photoresponsive materials, by Pierangelo Metrangolo, Giuseppe Resnati, Arri Priimagi

Author: Sławomir J. Grabowski
Publisher: MDPI
ISBN: 3038422452
Category : Science
Languages : en
Pages : 323

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This book is a printed edition of the Special Issue "Analysis of Hydrogen Bonds in Crystals" that was published in Crystals

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Publisher: Faraday Discussions
ISBN: 9781782629559
Category : Science
Languages : en
Pages : 512

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The halogen bond may be considered as a special case of sigma-hole bonding, wherein an electron donor interacts with the electrophilic region of a halogen atom. Within this broader picture, sigma-hole bonding can encompass a range of non-covalent interactions which are named after the atom bearing the electrophilic region, also known as the sigma-hole. This Faraday Discussion unites experimentalists and theoreticians, who are pushing the applicability of this broad class of interactions far beyond only the halogens. The book develops a fundamental understanding of key aspects of non-covalent interactions in solid-state materials, solution chemistry, biochemistry and the gas phase.

Author: Robin K. Harris
Publisher: John Wiley & Sons
ISBN: 0470699612
Category : Science
Languages : en
Pages : 523

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The content of this volume has been added to eMagRes (formerly Encyclopedia of Magnetic Resonance) - the ultimate online resource for NMR and MRI. The term "NMR Crystallography" has only recently come into common usage, and even now causes raised eyebrows within some parts of the diffraction community. The power of solid-state NMR to give crystallographic information has considerably increased since the CPMAS suite of techniques was introduced in 1976. In the first years of the 21st century, the ability of NMR to provide information to support and facilitate the analysis of single-crystal and powder diffraction patterns has become widely accepted. Indeed, NMR can now be used to refine diffraction results and, in favorable cases, to solve crystal structures with minimal (or even no) diffraction data. The increasing ability to relate chemical shifts (including the tensor components) to the crystallographic location of relevant atoms in the unit cell via computational methods has added significantly to the practice of NMR crystallography. Diffraction experts will increasingly welcome NMR as an allied technique in their structural analyses. Indeed, it may be that in the future crystal structures will be determined by simultaneously fitting diffraction patterns and NMR spectra. This Handbook is organised into six sections. The first contains an overview and some articles on fundamental NMR topics, followed by a section concentrating on chemical shifts, and one on coupling interactions. The fourth section contains articles describing how NMR results relate to fundamental crystallography concepts and to diffraction methods. The fifth section concerns specific aspects of structure, such as hydrogen bonding. Finally, four articles in the sixth section give applications of NMR crystallography to structural biology, organic & pharmaceutical chemistry, inorganic & materials chemistry, and geochemistry. About EMR Handbooks / eMagRes Handbooks The Encyclopedia of Magnetic Resonance (up to 2012) and eMagRes (from 2013 onward) publish a wide range of online articles on all aspects of magnetic resonance in physics, chemistry, biology and medicine. The existence of this large number of articles, written by experts in various fields, is enabling the publication of a series of EMR Handbooks / eMagRes Handbooks on specific areas of NMR and MRI. The chapters of each of these handbooks will comprise a carefully chosen selection of articles from eMagRes. In consultation with the eMagRes Editorial Board, the EMR Handbooks / eMagRes Handbooks are coherently planned in advance by specially-selected Editors, and new articles are written (together with updates of some already existing articles) to give appropriate complete coverage. The handbooks are intended to be of value and interest to research students, postdoctoral fellows and other researchers learning about the scientific area in question and undertaking relevant experiments, whether in academia or industry. Have the content of this Handbook and the complete content of eMagRes at your fingertips! Visit: www.wileyonlinelibrary.com/ref/eMagRes View other eMagRes publications here

Author: Lisa Kirchner
Publisher:
ISBN:
Category : Crystal growth
Languages : en
Pages : 202

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This research was to design and successfully engineer crystals using the non-covalent halogen bonding interaction. A halogen bond is an attractive interaction between a positive electrostatic potential on a halogen atom and a negative site on another molecule. Halogen bonds are increasingly recognized as an effective force for the self-assembly of molecules in predictable patterns to produce new materials with certain desirable properties. The research focused on the formation of large planar polyaromatic assemblies of molecules containing halogen bond donor and acceptor sites. The planar polyaromatic compounds were synthesized using multiple Sonogashira Coupling reactions. This is a cross-coupling reaction that forms carbon-carbon bonds between a terminal alkyne and an aryl halide using palladium catalysts. The X-ray crystal structures of the series of iodo- and bromo-phenylethynylphenylethynylpyridines were shown to form self-complementary dimers in the solid state. The perfluoroiodo- and perfluorobromophenylethynylphenylethynyl derivatives, 3-[{4-[(2-bromo-3, 4, 5, 6- tetrafluorophenyl)ethynyl]phenyl}ethynyl]pyridine, 3-[{4-[(2, 3, 4, 5-tetrafluoro-6-iodophenyl)ethynyl]phenyl}ethynyl]pyridine and 2-[{4-[(3-bromo-2, 4, 5, 6-tetrafluoro- phenyl)ethynyl]phenyl}ethynyl]pyridine, formed self-complementary halogen-bonded dimeric units in the solid state. In contrast, 3-[{4-[(2-bromo-4, 5-difluorophenyl)ethynyl]phenyl}ethynyl]pyridine formed a C-H···N hydrogen- bonded dimer.