bluuebunny/crossref_metadata_2025_split huggingface dataset:
NMR
Spectroscopy in Solution
Authors: García Jesús , Martins Lucas G. , Pons Miquel 
Published: February 2012

Abstract
Solution NMR provides valuable structural information on supramolecular complexes, the dynamics of their formation, and possible rearrangement between isomeric forms or the interplay between hosts and guests in supramolecular cavities. The atomic resolution of NMR provides direct access to the symmetry properties of supramolecular species. Line shapes in NMR spectra are sensitive to the time scale of dynamic processes. NOESY and ROESY experiments are among the most powerful tools to characterize supramolecular structures, although the dynamics of supramolecular complexes is inextricably mixed in these experiments.
Transient supramolecular interactions between low‐molecular‐weight‐guests and macromolecular hosts detected by solution NMR enable the use of low‐molecular‐weight spies to report on large, NMR invisible, structures. This concept extends the interfaces between supramolecular chemistry, biomolecular structure, and material sciences.
Computational Techniques (DFT,MM,TD‐DFT,PCM)
Authors: Sheehan Rosemary , Cragg Peter J. 
Published: February 2012

AbstractComputational techniques can be used to simulate molecular and atomic behavior based on fundamental descriptions of atomic and molecular orbitals (ab initioquantum mechanics), experimental data (a priorimolecular mechanics), or a combination of both (semiempirical methods). The choice of method depends on the task in hand and the computational resources available. Low‐level molecular mechanics, molecular dynamics, conformational analysis, and periodic boundary simulations are described along with quantum mechanical approaches (Hartree‐Fock, density functional theory, and other post‐Hartree‐Fock methods) and intermediate semiempirical methods. Keys to the success of any computational method are the adoption of an appropriate model and the methods used to generate that model. By constructing models that reflect both the correct structures of the complex and its components together with changes in experimental parameters, supramolecular phenomena, such as host–guest binding, can be studied in detail using theoretical models. Applications of these methods in the field of supramolecular chemistry are illustrated with examples drawn from crown ether, cyclodextrin, and calixarene complexes.
Diffusion Ordered
NMR
Spectroscopy (
DOSY
)
Authors: Macchioni Alceo , Ciancaleoni Gianluca , Zuccaccia Cristiano , Zuccaccia Daniele 
Published: February 2012

Abstract

This chapter deals with the applications of diffusion NMR spectroscopy to investigate supramolecular compounds in solution. It is organized in three main sections: (i) brief description of the basic concepts underlying self‐diffusion in solution and measurement of the self‐diffusion translational coefficient (
D
t
) by NMR experiments; (ii) critical discussion on the determination of accurate hydrodynamic dimensions (molecular weights) of supramolecular compounds by
D
t
through the Stokes–Einstein equation; (iii) deduction of thermodynamic self‐aggregation parameters using models of indefinite association. Emphasis is given to applications of diffusion NMR spectroscopy to supramolecular chemistry rather than to technical and theoretical aspects. Efforts are made to introduce new, potentially difficult concepts with suitable practical examples in order to facilitate the understanding to nonspecialist readers.
Mass Spectrometry and Gas‐Phase Chemistry of Supermolecules: A Primer
Authors: Dzyuba Egor V. , Poppenberg Johannes , Richter Sebastian , Troff Ralf W. , Schalley Christoph A. 
Published: February 2012

AbstractMass spectrometry offers unique tools to examine supermolecules in the gas phase. In this chapter, gas‐phase experiments that aim at determining the structures of supermolecules in solution and the gas phase, their reactivity in condensed phase and under environment‐free conditions, and their thermochemistry in the gas phase are discussed. A comparison of the gas‐phase properties with solution properties provides insight into the effects of solvation.
Supramolecular Electrochemistry
Authors: Flood Amar H. , Kaifer Angel E. 
Published: February 2012

Abstract
Electron transfer reactions afford a very powerful method to introduce controlled changes in supramolecular structures. This chapter provides a brief introduction to electrochemical parameters and voltammetric techniques that are commonly used to investigate supramolecular systems containing redox‐active groups. A discussion of redox‐active host–guest complexes is presented, alongside their corresponding diagnostic cyclic voltammetry titrations. Then we move on to describe the electrochemistry of redox‐switchable, mechanically interlocked molecules, such as rotaxanes and catenanes. The discussion includes thermodynamic considerations, as well as kinetic effects. We have strived to provide a number of selected examples that illustrate the power of electrochemical techniques, not only for characterization purposes but also as a versatile methodology to stimulate supramolecular systems and to control their structure and other chemical and physical properties.
Transport Experiments in Membranes
Authors: Matile Stefan , Sakai Naomi , Hennig Andreas 
Published: February 2012

Abstract
In this chapter, we describe methods to characterize the activity of synthetic transport systems in translocating molecules across otherwise impermeable membranes. The first two sections introduce methods with bulk membranes (U‐tube experiments) and planar or “black” lipid membranes (BLMs), and close with a more comprehensive overview of methods involving liposomes, in particular, large unilamellar vesicles (LUVs). The fourth section focuses on the application of these methods to the elucidation of the functional characteristics of synthetic transport systems. This includes sensitivity toward membrane composition, membrane potential, pH, anions, cations, molecular recognition (sensing), molecular transformation (catalysis), or light (photosynthesis).
Vesicles in Supramolecular Chemistry
Authors: Ravoo Bart Jan 
Published: February 2012

AbstractVesicles are self‐assembled nanoscale capsules consisting of a molecular layer enclosing an inner solvent compartment. Vesicles have been a versatile topic in supramolecular chemistry ever since the discovery that, besides phospholipids, also synthetic amphiphiles can form vesicles in aqueous solution. Vesicles are highly dynamic supramolecular structures that have been subject of investigation by many chemists over the last three decades. In particular, the range of building blocks for vesicles has expanded from “conventional” (i.e., phospholipid‐like) amphiphiles to block copolymers, giant amphiphiles, and supramolecular amphiphiles. Increasingly, vesicles are also assembled from nonconventional (i.e., non‐amphiphilic) components in aqueous as well as organic solvents. Vesicles can be tailor‐made to respond to external stimuli. Vesicles are also highly interesting biomimetic structures: molecular recognition of vesicles is a powerful model system for molecular recognition of biological membranes.
Hetero‐Crown Ethers—Synthesis and Metal‐Binding Properties of Macrocyclic Ligands Bearing Group 16 (S,Se,Te) Donor Atoms
Authors: Levason William , Reid Gillian 
Published: February 2012

AbstractThe development of hetero‐crown ethers containing neutral thio‐, seleno‐ and/or telluro‐ether donor atoms over the past 10 years is reviewed with the aim of providing a survey of the most significant advances in their preparations and metal‐binding properties (especially toward d‐block and p‐block acceptors).
Cryptands and Spherands
Authors: Lindoy Leonard F. , Park Ki‐Min , Sung Lee Shim 
Published: February 2012

AbstractThe cryptands and spherand are both categories of ligands exhibiting significant degrees of preorganization of their donor atom sets. The design, synthesis, and host–guest binding properties of representative examples of each ligand category are discussed, with emphasis on structure‐function relationships. A characteristic feature of both of these categories is their tendency to exhibit selective complexation behavior toward individual metal cations, especially alkali metal cations. Individual species from each category that bind ammonium and/or alkylammonium cations are also presented. Examples of spherand and cryptand derivatives, including “intermediate” ligand species of the hemispherand and cryptaspherands type, as well as chromoionophoric derivatives of each category, are also discussed. Spherand derivatives in which some or all of the anisyl groups of the “classical” spherands have been replaced by fluoro, cyano, or urea functions are described. Examples of both bicyclic and tricyclic cryptands and their cryptate derivatives, including anion‐binding systems and ones that yield binuclear metal complexes, are also discussed.
Calixarenes in Molecular Recognition
Authors: Baldini Laura , Sansone Francesco , Casnati Alessandro , Ungaro Rocco 
Published: February 2012

AbstractThis chapter summarizes the most important aspects of the chemistry of calixarenes and their applications in supramolecular chemistry. The first section gives a short summary of the synthesis and conformational properties of calixarenes and of their functionalization at the phenolic OH groups (lower rim) and at the para‐position of the aromatic nuclei (upper rim). The second section covers the properties of native and functionalized calixarenes (including chiral compounds) as receptors for the selective recognition of neutral molecules, cations, anions, and ion‐pairs in the solid state, organic media, and water solution. In the third section, the calixarenes are viewed as scaffolds for the construction of multivalent ligands able to target biomacromolecules eliciting or inhibiting a biological process. Calixarene glycoclusters, operating as efficient and selective multivalent inhibitors of vegetal and mammalian lectins; peptidocalixarenes, capable of disrupting protein–protein interactions; and guanidino‐calixarenes, able to target proteins or to condense DNA, acting, in this case, as efficient nonviral vectors for cell transfection, are discussed. When relevant, the use of calixarene receptors and multivalent ligands as active components of sensor devices for the detection of various analytes is also reported. Perspectives for future developments of calixarenes in supramolecular chemistry and bionanotechnology are indicated.
Cyclotriveratrylene and Cryptophanes
Authors: Hardie Michaele J. 
Published: February 2012

Abstract
A review of the chemistry and applications of cyclotriveratrylenes (CTVs) and cryptophanes is given. Synthetic approaches to CTVs and cryptophanes are discussed, including the recently reported mild cyclization conditions and strategies for the synthesis of lower symmetry cryptophanes. Host– guest and inclusion chemistry is surveyed, including binding of neutral and organic cations by cryptophanes in solution, clathrate structures of CTVs, the anion‐binding abilities of metalled CTVs and cryptophanes, the fullerene‐binding abilities of CTVs, and xenon binding by cryptophanes and their potential applications in xenon biosensors for imaging applications. The uses of CTVs and crytophanes as molecular platforms for other supramolecular chemistry applications are also discussed. These include development of coordination polymers with CTVs and cryptophanes; organic and metallo‐supramolecular prism‐like assemblies, some of which show unusual molecular topologies; and self‐organized systems such as liquid crystals and gels.
Carcerands and Hemicarcerands
Authors: Warmuth Ralf 
Published: February 2012

Abstract

Carcerands and hemicarcerands are spherical, hollow host molecules with inner cavities that are large enough to accommodate smaller organic guest molecules. Since the first synthesis of a carcerand in the mid‐1980s, a large variety of different hemicarcerands and carcerands have been prepared and their properties investigated. In this review, mechanism and scope of (hemi)carcerand synthesis, which is a templated reaction, is discussed. This includes recent work on dynamic hemicarcerands, in which building blocks are connected via dynamic covalent bonds, and gated hemicarcerands, which open and/or close in response to an external trigger such as irradiation or the addition of acid, base, or thiols. In the second part of this chapter, the molecular recognition properties of hemicarcerands are reviewed. As part of this, binding properties of chiral hemicarcerands and water‐soluble hosts are discussed. In the last part, applications of hemicarcerands as molecular reaction flasks are reviewed. Through‐shell reactions between an encapsulated reactant and a bulk‐phase reactant include amine protonation, oxidation/reduction, H/D exchange, and nucleophilic substitutions and additions. In most of these reactions, bond formation/breaking takes place in a size‐restricted portal in the host shell. Thus, scope and reaction rate depend on guest orientation in the inner phase as well as size and shape of the bulk‐phase reactant relative to those of the hemicarcerand's portal. Hemicarcerands have also been used extensively for the inner‐phase stabilization of reactive intermediates. If a reactive intermediate is generated photochemically or thermally in the inner phase of the hemicarcerand, the surrounding host prevents dimerization of the intermediate or reactions with bulk‐phase reactants that cannot pass through an opening in the host shell. Many otherwise fleeting intermediates gain longevity through this extrinsic stabilization, making possible their observation, for example, by NMR spectroscopy. Examples that are discussed include cyclobutadiene, benzyne,
anti
‐Bredt olefins, cyclic allenes and ketenimines, carbenes, and nitrenes. Furthermore, investigations of photoelectron transfer and energy transfer across the shell of hemicarcerands have improved our understanding of these important photophysical processes. Recent advances in this area are discussed.
Cucurbituril Receptors and Drug Delivery
Authors: Day Anthony Ivan , Collins J. Grant 
Published: February 2012

AbstractThe relatively new family of molecular host–guest macrocycles known as cucurbit[n]uril is discussed in the context of a drug delivery system. In less than a decade, cucurbit[n]uril and cucurbit[n]uril‐based supramolecular structures have emerged as promising vehicles for drug delivery. For the first time, this review brings together the results of cucurbit[n]uril‐drug studies and provides a general understanding of the relationship between drugs and this new type of molecular host.Numerous examples are discussed that highlight the advantages and disadvantages that cucurbit[n]uril can offer, these include improvements in bioavailability and protection, increased stability, reduction in toxicity, and targeted delivery. The current knowledge of toxicology and pharmokinetics of cucurbit[n]uril is also evaluated. Finally, as a drug delivery vehicle, a number of mechanisms are discussed as to the release of the drug. Drug activity results are presented that indicate that there are generally minimal negative effects and there are significant advantages to drug encapsulation involving cucurbit[n]uril. General methods for the preparation of encapsulated drugs are provided, together with a convenient method of characterization using1H NMR.
Anion Receptors Containing Heterocyclic Rings
Authors: Gale Philip A. , Haynes Cally J. E. 
Published: February 2012

Abstract
Heterocyclic groups can play key roles as hydrogen bond donors and charged components in a wide range of anion receptors. This chapter reviews the roles the heterocycles play in anion recognition, covering pyrrole‐based systems (both macrocyclic and acyclic, including synthetic systems and natural products such as prodigiosin), indole‐based receptors, and foldamers‐ and charged‐imidazolium‐based hosts. The chemistry of pyridine‐ and quinoline‐based receptors, including metal‐templated systems that employ transition metals to assemble simple organic components, and the role of bipyridinium in anion complexation and sensing are also reviewed. Finally, the chemistry of 1,2,3‐triazoles as components of hosts that use CH· · ·anion hydrogen bonds to complex anionic guests is examined.
Amide and Urea‐Based Receptors
Authors: Hossain Md. Alamgir , Begum Rowshan A. , Day Victor W. , Bowman‐James Kristin 
Published: February 2012

AbstractThe chemistry, binding, and structure of amide‐ and urea‐based receptors, as well as its thioamide‐ and thiourea‐based corollaries are described. The chapter begins with a short historical introduction of these hosts as ligands for anions, followed by a description of their chemical properties, including similarities and differences in bonding. The remainder of the chapter provides examples of the two types of receptors, the monodentate amides/thioamides, and the chelating ureas/thioureas, in order of increasing dimensionality, that is, acyclic, monocyclic, and bicyclic and higher order hosts. Features such as common (and different) structural motifs, preorganization, and the unique chemistry of some of these hosts and their guests are described.
Receptors for Nucleotides
Authors: García‐España Enrique , Belda Raquel , González Jorge , Pitarch Javier , Bianchi Antonio 
Published: February 2012

AbstractRecognition and activation of nucleotides by polyammonium receptors constitute an important target in supramolecular chemistry since the very beginning of this field. Nucleotides have three components: (i) the polyphosphate chain, (ii) the sugar moiety, and (iii) the nucleobase, which permit their multipoint binding through attractions between opposite charges, hydrogen bonding, π‐stacking, CH–π interactions, and so on. In this chapter, different receptors for nucleotides, most but not all of them consisting polyamines, are examined, focusing on their molecular structure that enables different binding modes to be operated. Also, a number of examples of nucleotide binding through metal complex formation are presented and discussed. The ATPase and/or kinase activity of abiotic molecules, in particular, of the macrocycle O‐BISDIEN, is briefly introduced. In the last part of the chapter, examples of receptors that are able to selectively sense nucleotides through different operational mechanisms are presented.
Metal Complexes as Receptors
Authors: Loeb Stephen J. 
Published: February 2012

Abstract

The incorporation of hydrogen‐bond donor or acceptor groups into ligands followed by their coordination to inert transition metals has proven to be a successful methodology for creating unique metal complex receptors for a wide variety of anions, some neutral molecules, and a limited number of cations. The metal ion can participate in binding a guest indirectly via second‐sphere coordination or directly via simultaneous first‐ and second‐sphere coordination. This chapter contains two major sections that outline the design strategies and describe a variety of metal complexes that function as receptors for (i) neutral molecules, (ii) cations, and (iii) anions. Under the heading of receptors for neutral molecules, the focus is on increasing complexity with respect to the targeted guest beginning with simple species such as H
2
O and NH
3
and featuring biologically important molecules such as DNA nucleobases. The section on metal complexes as anion receptors is structured to shed light on the different avenues used to design receptors and the structural features of these systems. A common theme is the idea that host–guest assemblies may have complicated structures, but the ligands themselves do not require tedious synthetic routes to prepare and coordination to the metal center is facile. Thus, the combination of coordination chemistry and noncovalent interactions such as hydrogen bonding and π‐stacking can be viewed as a powerful tool for molecular and ion recognition. The state of the art is advanced enough to allow targeting of specific guests by tailoring both the metal–ligand and host–guest interactions.
Hydrogen‐Bonding Receptors for Molecular Guests
Authors: Wilson Andrew J. 
Published: February 2012

Abstract
Hydrogen bonding is considered by many to be the “masterkey” of molecular recognition — owing to its strength and directionality — playing a key role in the assembly of biological supramolecular ensembles and architectures. Consequently, its study and exploitation within the context of host–guest chemistry has been a cornerstone of modern supramolecular chemistry, resulting in implementation within numerous applied settings such as catalysis and materials assembly. This chapter outlines the core concepts used to elaborate receptors that employ hydrogen bonding through modern efforts to recognize challenging targets in competitive media alongside a brief introduction covering the areas where such receptors are exploited.
Synthesis of Supramolecular Nanotubes
Authors: García‐Fandiño Rebeca , Amorín Manuel , Granja Juan R. 
Published: February 2012

AbstractIn the last few years, interest on nanotubes have induced the development of programs for the preparation of noncovalently bonded self‐organizing nanotubes from a variety of different methods, in most cases inspired by nature. These strategies include helically folded linear species, hollow bundles of rod‐like units, rolled‐up sheets, helically juxtapositioned truncated wedges, and stacked rings.
Self‐Assembly of Macromolecular Threaded Systems
Authors: Tachibana Yuya , Nakazono Kazuko , Takata Toshikazu 
Published: February 2012

Abstract
Recently, a polyrotaxane network material has been practically used, for the first time, as a coating material for mobile phones in Japan. This is an epoch‐making event in the science and technology of interlocked molecules, macromolecules, and related materials. Polymers possessing interlocked structures as key skeletons are, therefore, the most promising and intriguing materials, especially in the application fields. Polyrotaxanes and polycatenanes are characterized by the specific features based on the unique mobility of the noncovalently bonded components in their special polymer structures, such as molecular rotaxanes and catenanes, leading to the construction of a variety of sophisticated systems. In particular, when wheel components and a chain polymer form a macromolecular threaded system (i.e., polyrotaxane), combining the wheel components of different molecules results in producing the cross‐linked points that can move on the chain. Such a type of “topological cross‐linking” of polyrotaxane network can provide special mobility to the polymer chains, as de Gennes suggested in his paper entitled “Sliding Gels.” The topological cross‐linking is clearly distinguished from both physical and chemical cross‐linkings with little mobility of polymer chains. Thus, the research area of interlocked polymer systems has collected much attention from the fields of both supramolecular and polymer sciences, and the active investigation on them must be continued in the future, judging from the enthusiastic activity in materials science fields today.
In a whole research trend of interlocked polymers, being parallel to the development of the synthetic methods of interlocked polymers, various applications of them have been studied simultaneously. This chapter overviews the development of synthetic methods and applications of interlocked polymers such as polyrotaxane, polycatenane, and their networks that have been reported in these two decades. The works introduced are mainly the original ones. Owing to the limited space for this chapter, the authors cannot refer to the details of each work, although most works are very interesting. The detailed explanation of the important works published up to 2009 can be found in many reviews, including two comprehensive articles of Gibson and Stoddart on polyrotaxanes and polycatenanes in addition to a lot of review articles and books on the rotaxanes and catenanes that devote a small space for the polymers.