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Author: Yijue Xu Publisher: ISBN: Category : Languages : en Pages :
Book Description
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: Yijue Xu Publisher: ISBN: Category : Languages : en Pages :
Book Description
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: Patrick Szell Publisher: ISBN: Category : Languages : en Pages :
Book Description
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: Graham A. Webb Publisher: Springer Science & Business Media ISBN: 1402039107 Category : Technology & Engineering Languages : en Pages : 1889
Book Description
A comprehensive collection of the applications of Nuclear Magnetic Resonance (NMR), Magnetic Resonance Imaging (MRI) and Electron-Spin Resonance (ESR). Covers the wide ranging disciplines in which these techniques are used: * Chemistry; * Biological Sciences; * Pharmaceutical Sciences; * Medical uses; * Marine Science; * Materials Science; * Food Science. Illustrates many techniques through the applications described, e.g.: * High resolution solid and liquid state NMR; * Low resolution NMR, especially important in food science; * Solution State NMR, especially important in pharmaceutical sciences; * Magnetic Resonance Imaging, especially important for medical uses; * Electron Spin Resonance, especially important for spin-labelling in food, marine and medical studies.
Author: Publisher: Academic Press ISBN: 0128209739 Category : Science Languages : en Pages : 380
Book Description
Annual Reports on NMR Spectroscopy, Volume 100, is a premier resource for both specialists and non-specialists who are looking to become familiar with new techniques and applications in NMR spectroscopy. Chapters in this new release cover In Operando NMR Studies, Recent Developments in Automotive Differential Analysis of NMR Results, Applications of SIMPSON to NMR Studies of Peptides and Proteins, Recent Developments in NMR Line Shape Analysis, and more. - Serves as the premier resource for learning the new techniques and applications of NMR spectroscopy - Provides a key reference for chemists and physicists using NMR spectroscopy to study the structure and dynamics of molecules - Covers all aspects of molecular science, including MRI (Magnetic Resonance Imaging)
Author: Teresa Lehmann Publisher: MDPI ISBN: 3038429937 Category : Science Languages : en Pages : 307
Book Description
Nuclear Magnetic Resonance (NMR) spectroscopy is a nondestructive technique that can be used to characterize a wide variety of systems. Sustained development of both methodology and instrumentation have allowed NMR to evolve as a powerful technology, with applications in pure sciences, medicine, drug development, and important branches of industry. NMR provides precise structural information down to each atom and bond in a molecule, and is the only method for the determination of structures of molecules in a solution. This book compiles a series of articles describing the application of NMR in a variety of interesting scientific challenges. The articles illustrate the versatility and flexibility of NMR.
Author: Stefan Huber Publisher: John Wiley & Sons ISBN: 3527347313 Category : Technology & Engineering Languages : en Pages : 418
Book Description
Long-awaited on the importance of halogen bonding in solution, demonstrating the specific advantages in various fields - from synthesis and catalysis to biochemistry and electrochemistry! Halogen bonding (XB) describes the interaction between an electron donor and the electrophilic region of a halogen atom. Its applicability for molecular recognition processes long remained unappreciated and has mostly been studied in solid state until recently. As most physiological processes and chemical reactions take place in solution, investigations in solutions are of highest relevance for its use in organic synthesis and catalysis, pharmaceutical chemistry and drug design, electrochemistry, as well as material synthesis. Halogen Bonding in Solution gives a concise overview of halogen bond interactions in solution. It discusses the history and electronic origin of halogen bonding and summarizes all relevant examples of its application in organocatalysis. It describes the use of molecular iodine in catalysis and industrial applications, as well as recent developments in anion transport and binding. Hot topic: Halogen bonding is an important interaction between molecules or within a molecule. The field has developed considerably in recent years, with numerous different approaches and applications having been published. Unique: There are several books on halogen bonding in solid state available, but this will be the first one focused on halogen bonding in solution. Multi-disciplinary: Summarizes the history and nature of halogen bonding in solution as well as applications in catalysis, anion recognition, biochemistry, and electrochemistry. Aimed at facilitating exciting future developments in the field, Halogen Bonding in Solution is a valuable source of information for researchers and professionals working in the field of supramolecular chemistry, catalysis, biochemistry, drug design, and electrochemistry.
Author: G. A. Webb Publisher: Royal Society of Chemistry ISBN: 1847550606 Category : Medical Languages : en Pages : 512
Book Description
As a spectroscopic method, nuclear magnetic resonance (NMR) has seen spectacular growth, both as a technique and in its applications. Today's applications of NMR span a wide range of scientific disciplines, from physics to biology to medicine. Each volume of Nuclear Magnetic Resonance comprises a combination of annual and biennial reports which together provide comprehensive coverage of the literature on this topic. This Specialist Periodical Report reflects the growing volume of published work involving NMR techniques and applications, in particular NMR of natural macromolecules, which is covered in two reports: NMR of Proteins and Nucleic Acids and NMR of Carbohydrates, Lipids and Membranes. For those wanting to become rapidly aquainted with specific areas of NMR, Nuclear Magnetic Resonance provides unrivalled scope of coverage. Seasoned practitioners of NMR will find this an invaluable source of current methods and applications.
Author: Pierangelo Metrangolo Publisher: Springer ISBN: 3319140574 Category : Science Languages : en Pages : 286
Book Description
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: Paul Hodgkinson Publisher: Royal Society of Chemistry ISBN: 1839163917 Category : Science Languages : en Pages : 299
Book Description
Applications of nuclear magnetic resonance span a wide range of scientific disciplines, from physics to medicine. For those wanting to become acquainted with NMR or seasoned practitioners, this is a valuable source of current methods and applications.
Author: Yijue Xu
Author: Yijue Xu
Author: Jasmine Viger-Gravel
Author: Patrick Szell
Author: Graham A. Webb
Author: 
Author: Teresa Lehmann
Author: Stefan Huber
Author: G. A. Webb
Author: Pierangelo Metrangolo
Author: Paul Hodgkinson