bluuebunny/crossref_metadata_2025_split huggingface dataset:
Noncovalent Interactions in Crystals
Authors: Gilli Paola , Gilli Gastone 
Published: February 2012

AbstractThe over 500 000 structures collected in current crystallographic databases represent the greatest archive of noncovalent molecular interactions ever conceived by man. Their analysis provides an invaluable basis for understanding these interactions in the crystalline state and for transferring this knowledge to gas phase and condensed phases, such as pure liquids or solutions in polar and nonpolar solvents. This chapter is intended to review the different classes of noncovalent interactions and to supply the mathematical background for their description.For the sake of clarity, the treatment distinguishes betweenphysicalandchemicalinteractions. Physical interactions are considered essentially independent of molecular constitution and deriving from (i)van der Waals forces(atomic repulsion/exchange and attraction/dispersion terms); (ii)electrostatic multipolar forces(mostly monopolar and dipolar terms); and (iii)hydrophobic forces, a kind of interaction that develops in crystal clathrates and water solutions. Conversely, interactions of chemical nature are strictly related to the physicochemical properties of molecules with particular concern for (iv) groups that are either Brønsted acids (proton donors, DH) or Brønsted bases (proton acceptors, :A) and may interact by formingDH⋯:A hydrogen bondsand (v) groups that are either Lewis bases (electron donors, D:) or Lewis acids (electron acceptors, :A) and may interact by formingD: → Aelectron donor–acceptor (EDA) orcharge‐transfer(CT)interactions.Special emphasis is given to interactions that play a determinant structure‐directing role in molecular interaction and recognition phenomena, such as hydrogen and halogen bonding.
Cocrystals: Synthesis, Structure, and Applications
Authors: Aakeröy Christer B. , Chopade Prashant D. 
Published: February 2012

Abstract
The crystal structure of a compound, the 3D orientation and organization of molecules in a highly regular manner, ultimately determines most of the fundamental physical properties of that particular material, for example, thermal stability, hygroscopicity, conductivity, and mechanical strength. Consequently, an ability to control and change the crystalline environment of a material without altering the molecular properties would be of enormous significance to both manufacturers and consumers of solid specialty chemicals such as pharmaceuticals, pigments, energetic materials, toxins, foodstuff, and detergents.
Preparation of cocrystals—homogeneous crystalline solids composed of different molecular building blocks—offers an additional path for incorporating functional molecules, active ingredients, within a crystalline casing, but the synthetic challenges associated with supramolecular synthesis are numerous and nontrivial.
This chapter describes several strategies for the assembly of cocrystals using hydrogen bonds and halogen bonds and provides a more in‐depth examination of how the electrostatic charge on individual attempts can be used to control efficiency and selectivity of supramolecular synthesis. Finally, a few examples of applications of cocrystals in pharmaceutical sciences are discussed.
Polymorphism: Fundamentals and Applications
Authors: Aitipamula Srinivasulu , Nangia Ashwini 
Published: February 2012

AbstractPolymorphism is the ability of a compound to exist in more than one crystalline modification through different arrangements of the molecules in the solid state. Polymorphism has enormous economic and practical implications because of its ability to alter the physical and chemical properties of active pharmaceutical ingredients. The identification and complete characterization of polymorphs in the early stages of drug development is a necessary step to avoid serious financial setback in drug development and manufacturing. Thanks to new techniques such as high‐throughput screening and advances in analytical methods it has become possible to explore solid‐form diversity even with a small amount of sample in a short time. This chapter attempts to provide an overview of the fundamentals of polymorphism and the factors that control the crystallization of polymorphs. The potential implications of polymorphism in the pharmaceutical industry are highlighted with some recent examples.
Mechanical Preparation of Crystalline Materials. An Oxymoron?
Authors: Braga Dario , Dichiarante Elena , Grepioni Fabrizia , Lampronti Giulio I. , Maini Lucia , Mazzeo Paolo P. , D'Agostino Simone 
Published: February 2012

AbstractThe thesis developed in this chapter is that reactions taking place between molecular materials (intersolid) or within a molecular material (intrasolid) can be used to produce new crystalline materials in solvent‐free conditions and often with quantitative yields. The most common approach to intersolid and, to lesser extent, intrasolid processes is based on the mechanical cogrinding of the solid reactants, which implies comminution of the reactants. The implicit consequence of this is the lack of crystals of the product suitable for single‐crystal X‐ray diffraction. The mechanical process yields a polycrystalline or amorphous product, with structure and composition that often differ from that obtained from solution crystallization.
Physico‐Chemical Aspects of Inclusion Compounds
Authors: Báthori Nikoletta B. , Nassimbeni Luigi R. 
Published: February 2012

AbstractWe summarize the macro properties of organic inclusion compounds in terms of their kinetics of desorption and enclathration, their thermal stability, and the selectivity that host compounds exhibit toward a given guest from a guest mixture. We note the importance of the mechanism of enantiomeric resolution and correlate the various phenomena with the structure of the inclusion compounds.
Templated [2+2] Photodimerizations in the Solid State
Authors: Elacqua Elizabeth , Laird Rebecca C. , MacGillivray Leonard R. 
Published: February 2012

AbstractThis chapter describes how principles of supramolecular chemistry based on the use of small‐molecule and metal‐organic templates can be used to direct intermolecular [2+2] photodimerizations in the organic solid state. The approach provides a general means to gain control of reactivity so as to provide access to molecules difficult to achieve in solution stereospecifically, in quantitative yield, and in gram amounts.
Soft Matter Science—a Historical Overview with a Supramolecular Perspective
Authors: Smith David K. 
Published: February 2012

AbstractSoft matter science is one of the most active interdisciplinary fields of research, sitting at the interface between chemistry, biology, and condensed matter physics. One of the reasons for the intense interest in soft matter systems is that they are highly dynamic and responsive to a range of different stimuli, making them of interest for a wide range of smart applications. This article provides an introductory overview of the topic of soft matter science and attempts to place it in a historical context, tracing the genesis of the field from its disparate roots in colloid science, liquid crystals, and polymer chemistry. In particular, the article demonstrates how soft matter systems relate to the area of supramolecular science, and it attempts to connect the genesis of the supramolecular approach to soft matter nanoscience with the disparate areas of research that underpin it. In this way, it is possible to achieve a holistic approach to the development of soft matter systems with applications in nanoscience and technology.
Supramolecular Dendrimer Chemistry
Authors: Soler Monica , Newkome George R. 
Published: February 2012

AbstractThe field of dendrimers and dendrons has grown over the past one score and five years in both academic and industrial areas, becoming an interdisciplinary field between chemistry, physics, and medicine, leading specifically to nanoscience, and inspiring chemists to develop new materials and to explore their imbedded technological applications. Dendrimers are well‐defined highly branched three‐dimensional macromolecules with nanoscale scope and globular hollow structures with increased generation. One reason for their rapid growth is due to their precise structures and prearranged physical and functional properties such as the ability to encapsulate guests as well as polyfunctional surface constructs, control over structural unit positioning during synthesis, solubility, ease of construction, and limitless structural modifications. Owing to their macromolecular distinctiveness, this short overview will introduce the general properties of dendrimers and dendrons, with specific focus on their structure and host–guest chemistry where molecular recognition may occur within the interior of the dendrimer or at its surface, as well as consider their interactions between themselves or with other nano‐objects.
Stimuli‐Responsive and Motile Supramolecular Soft Materials
Authors: Topham Paul D. , Ryan Anthony J. 
Published: February 2012

AbstractMotility is achieved by energy conversion. In nature, motility is linked to stimuli‐responsive behavior occurring at the nanometer length scale, the operation of molecular machines. Nature's molecular machines all comprise of actuator material; where an actuator is a device that converts one source of energy into another to generate a force or motion. Such stimuli‐responsive materials are often referred to assmartbecause they respond to changes in their surrounding environment. The ability of a substance to react to an external trigger is the key step in actuation. However, the fabrication of these devices relies on a set of strict design rules concerning physics at the molecular level. This chapter discusses these design rules and highlights advances in the field of smart polymers that are powered by changes in magnetic field, light, and chemical surroundings. In each case, the reader will be guided through the basic operation (i.e., how they work), common manufacturing strategies, characterization procedures, and potential applications.
Self‐Assembly of Facial Amphiphiles in Water
Authors: Boekhoven Job , van Rijn Patrick , van Esch Jan H. 
Published: February 2012

Abstract
In this article, an overview is given concerning facial amphiphiles in nature, bio‐, and supramolecular chemistry. In facial amphiphiles, the hydrophilic and hydrophobic parts are separated by the longitudinal axis of molecule, this in contrast to head‐tail amphiphiles in which the hydrophilic and hydrophobic groups each occupy one end of an elongated molecule. This different distribution of hydrophilic and hydrophobic groups with respect to the overall molecular shape leads to a variety of functions which are unique for facial amphiphiles, including emulsification and solubilization of hydrophobic compounds, as antibiotics and pore‐forming agents in bilayer membranes, and as membrane curvature sensing and regulating agents. In nature facial amphiphiles occur mainly as low molecular weight compounds such as the bile acids, and as a variety of peptides, alone or as part of larger proteins. Synthetic facial amphiphiles have been synthesized ranging from low molecular weight to polymers and dendrimers for the purpose of novel building blocks for supramolecular architectures and to mimic the natural functions of facial amphiphiles. In this article, we gave an overview of the self‐assembly and interfacial behavior of both natural as well as synthetic facial amphiphiles and discuss their most important biological functions and applications.
Self‐Assembly of Surfactants at Solid Surfaces
Authors: Ferrari Michele 
Published: February 2012

Abstract
Recent studies have shown how surfactants, well beyond their huge impact in our everyday life, have become the key tool to manipulate surface properties in order to fulfill new research and industrial requirements ranging from fluids to disperse systems management, bio and nanotechnologies naming but a few.
In this work, the author has focused on self‐assembly of surfactants at solid surfaces discussing both theoretical and simulation aspects, and conventional and more advanced experimental techniques to assess morphological, chemical, or physicochemical features of these phenomena from the nano to the macroscale.
A wide range of examples has been shown to evaluate their application potential.
Self‐Organization and Self‐Assembly in Liquid‐Crystalline Materials
Authors: Goodby John W. , Saez Isabel M. , Cowling Stephen J. 
Published: February 2012

AbstractLiquid crystals comprise a number of thermodynamically stable states, which occur between the melting of a material and the formation of an amorphous liquid. Liquid crystals are the quintessential molecular materials of the modern era, being found in many types of display device, from watches and calculators to laptop computers and TVs, in high yield strength polymeric materials such as Kevlar®, and in soft materials such as soaps and detergents. Control of the self‐organizing and self‐assembling properties of liquid crystals makes these applications possible. In the following text, we describe many types of interactions at various levels of molecular complexity in the formation and stabilization of liquid crystal mesophases. The discussion ranges from covalently bound materials through to ionic‐ and charge‐transfer systems, and from molecular materials to super‐ and supramolecular systems.
Covalent Capture of Self‐Assembled Soft Materials
Authors: Gong Bing 
Published: February 2012

Abstract
This chapter describes the covalent capture of soft materials with examples from covalently captured liquid crystals as well as gels of small molecules and polymers. The interplay of self‐assembly and the incorporation of various covalent bonds, including irreversible and covalent reversible bonds, are discussed. The development of basic, tunable association units allowing the systematic control of molecular assembly and covalent capture is speculated.
Designing Peptide‐Based Supramolecular Biomaterials
Authors: Jayawarna Vineetha , Ulijn Rein V. 
Published: February 2012

Abstract
One rapidly emerging area where supramolecular chemistry can have a significant impact is in biomaterials science, and specifically in the design of cell‐contacting biomaterials. Aspects that are known to influence cell behavior at any particular time include chemical signals, mechanical properties (i.e., gel stiffness), and topographical signals related to fiber sizes and alignment. In this chapter, we provide an overview of current supramolecular chemistry strategies in the design of cell scaffolds based on peptides and their derivatives. The approaches discussed include those inspired by secondary or quaternary structures (α‐helix, β‐sheet, collagen triple helix) found in natural proteins as well as synthetic sequences such as aromatic and aliphatic peptide amphiphiles. We then discuss how supramolecular fibers based on peptides can be designed to control and direct (stem) cell behavior by engineering stiffness and chemical presentation of bioactive ligands.
Supramolecular Organocatalysis
Authors: Woods Philip A. , Smith Andrew D. 
Published: February 2012

Abstract
The use of small organic molecules as catalysts for a wide range of asymmetric transformations has blossomed into a remarkably diverse field under the global heading of organocatalysis. A key central theme of organocatalysis is molecular recognition, which relies on established patterns of reactivity and interactions common to traditional “supramolecular chemistry” such as hydrogen bonding, π‐stacking, cation–π, ionic, and hydrophobic interactions. This chapter presents selected highlights of these approaches in organocatalysis and also compares the way in which Nature's enzymatic supramolecular catalysts have inspired synthetic strategies and modes of action of many organocatalytic approaches to chemical reactivity.
Reactions in Solid‐State Inclusion Compounds
Authors: Harris Kenneth D.M. , Palmer Benjamin A. , Edwards‐Gau Gregory R. 
Published: February 2012

AbstractThis chapter focuses on chemical reactions occurring within solid organic inclusion compounds, encompassing a broad range of inclusion compounds and a wide variety of different reaction types, including reactions of the guest molecules (such as dimerization, polymerization, cyclization, isomerization, and decomposition), reactions involving the host molecules, and guest exchange processes. In many cases, chemical transformations of guest molecules confined within solid host structures proceed with a high degree of selectivity toward a single product, and often with a high degree of stereoselectivity and/or enantioselectivity, as a consequence of the geometrical constraints imposed on the reacting molecules by the host structure. For this reason, the products obtained from such reactions are often significantly different from those obtained from the corresponding reactions in the solution state or in the “pure” crystalline phase of the guest molecules. Through the examples highlighted in this chapter, general issues relating to reactions in solid organic inclusion compounds are rationalized and discussed.
Functional Polymers
Authors: Chappell David , Greenland Barnaby W. , Hayes Wayne 
Published: February 2012

Abstract
This chapter outlines key developments of the combination of key supramolecular principles and polymer chemistry, notably in the realization of novel catalyst systems. Novel catalysts have been produced that offer reactivity under conditions that more traditional hetero‐ or homogeneous catalysts do not tolerate. In particular, molecularly imprinted polymer networks have been used successfully and notable examples are described in this chapter. In addition to cross‐linked polymer networks, the combination of hyperbranched polymer architectures with molecular recognition has also afforded novel catalyst systems, and recent developments in this area are outlined. Finally, the application of sonochemistry to self‐assembled latent catalysts is reviewed.
Nucleic Acid Mimetics
Authors: Coppock Matthew B. , Williams Mary Elizabeth 
Published: February 2012

AbstractThe naturally occurring nucleic acids have the ability to selectively recognize complementary partners, and by self‐assembly create supramolecular structures capable of storage of genetic information. Chemists are interested in mimicking the makeup and properties of nucleic acids to aid in the understanding of the natural systems, and to create functional nanomaterials for a broad range of potential applications. Nucleobase analogs, including fluorescent, hydrophobic, and inorganic bases, have been successfully incorporated into modified DNA and RNA strands. Analogs of the sugar‐phosphate backbone have been constructed to increase the strength of binding between strands, and to create alternative scaffolds for both natural and synthetic nucleobases. Synthetic analogs with a combination of nucleobase and backbone mimics provide routes toward materials with tuned physical properties geared toward specific functions. This review first describes the properties of nucleic acids that serve as models for creation of synthetic analogs before presenting recent research in each of these categories of mimics.
Supramolecular Approaches to the Study of Glycobiology
Authors: Lindhorst Thisbe K. , Kubik Stefan 
Published: February 2012

AbstractEvery mammalian cell is surrounded by carbohydrate conjugates forming a nano‐dimensioned layer termed “glycocalyx,” a name derived from the Greek words “glykos” for “sugar” and “kalyx” for “coat.” A cell's glycocalyx might expand to a width of 100 nanometers and more, with glycoconjugate structures of vast complexity projecting from the cell surface into an aqueous environment. Lectins are able to probe this environment by selectively binding to certain carbohydrate epitopes, and the concert of the corresponding recognition events is essential in cell‐cell communication. Because of the extremely high constitutional complexity of the glycocalyx and the sensitivity of its supramolecular characteristics to, for example, the presence of ions and many other entities, it has been difficult to unravel the secrets of glycobiology, in particular how carbohydrate‐carbohydrate and carbohydrate‐protein interactions are governed and fine‐tuned. Nevertheless, a number of important aspects of carbohydrate recognition have been identified, such as critical factors for carbohydrate complexation in water, the importance of multivalency in carbohydrate‐protein interactions, and the potential of the biosynthetic machinery that makes and delivers complex glycoconjugates. In this chapter, current knowledge about how Nature achieves carbohydrate recognition is summarized. On this basis, different approaches are presented, most of which are firmly rooted in supramolecular chemistry, that aim at elucidating the molecular basis of glycobiology. These approaches comprise the development of low‐molecular weight mimics for lectins, so‐called synthetic carbohydrate receptors, on the one hand and of multivalent and highly complex glycomimetics on the other.
Porphyrinoids: Highly Versatile, Redox‐Active Scaffolds for Supramolecular Design and Biomimetic Applications
Authors: Hill Jonathan P. , D'Souza Francis , Ariga Katsuhiko 
Published: February 2012

AbstractPorphyrinoids are a growing class of oligopyrrole macrocycles that have structural and physical properties additional to those of the traditional tetrapyrrolic porphyrin macrocycles. In this chapter, after an initial description of how the porphyrins have been adapted for self‐assembly and supramolecular synthesis, we describe several aspects of porphyrinoid supramolecular systems, finally focusing on the use of an oxoporphyrinogen core as a scaffold for assembling complex oligochromophoric manifolds by using a combination of synthetic and coordination chemistries. An important feature of porphyrinoids is their increasing amenability to core functionalization, unlike the porphyrins in which peripheral derivatization has been the usual method for augmentation. Core functionalization introduces different molecular morphological possibilities for the porphyrinoids complementary to those available for the porphyrins. In fact, porphyrins and porphyrinoids can be agglomerated in supramolecular assemblies to exploit the functional and synthetic properties of both sets of compounds.
The Role of Supramolecular Chemistry in Responsive Vectors for Gene Delivery
Authors: LaManna Caroline M. , Grinstaff Mark W. 
Published: February 2012

Abstract
The investigation of the self‐assembly between nucleic acids and cationic molecules, such as lipids, polymers, or dendrimers, has guided and will continue to guide the development of nonviral vectors for gene delivery. By engineering these types of supramolecular complexes to facilitate the transport, protection, and release of DNA, scientists are working to overcome the barriers that have limited transfection efficiencies. Understanding the self‐assembly of cationic lipids into liposomes or micelles, as well as studying the structure of their resulting complexes with DNA, is key to enhancing gene delivery research. This chapter discusses cationic lipid–DNA supramolecular structures, their role in gene transfection, and the synthesis and evaluation of new responsive cationic lipids which aim to control both the complexation and release of DNA.