bluuebunny/crossref_metadata_2025_split huggingface dataset:
Self‐Assembled Links: Catenanes
Authors: Evans Nicholas H. , Beer Paul D. 
Published: February 2012

Abstract
Catenanes are molecules consisting of two or more rings that are mechanically interlocked requiring the cleavage of a chemical bond to separate the macrocyclic components. Initial attempts to synthesize these aesthetically pleasing molecules via nontemplated methods were blighted by low yields and lengthy syntheses, and it took Sauvage's use of the copper(I) cation as a template for the synthesis of a [2]catenane to ignite intense research activity in this field. This chapter summarizes this groundbreaking work and the array of template interactions such as metal cation, charge transfer π‐π stacking, hydrogen bonding, and anion coordination that have since been utilized to produce catenanes. Attention is then turned toward the progress that has been made in the practical applications of these mechanically chain linked structures, such as the control of their molecular motion, immobilization onto surfaces, and efforts to incorporate them into extended structures such as polymers and metal organic frameworks.
Viruses as Self‐Assembled Templates
Authors: Rego Jennifer M. , Yi Hyunmin 
Published: February 2012

Abstract
Research endeavors in employing viruses and virus‐like protein assemblies as biologically derived nanotemplates for nanomaterials synthesis and device fabrication have recently experienced significant growth. Materials and applications arising from this novel bottom‐up assembly approach vary widely from metal and metal oxide nanoparticles and nanowires for catalysis and nanoelectronics, high surface area electrodes for energy applications, to sensing or tissue engineering scaffolds for biomedical applications. By harnessing and manipulating the exquisite control that Nature has provided, the overarching goal for this emerging field of nanobiotechnology has been to achieve features and performances that transcend what is possible from inorganic, man‐made methods. In this review, we describe the chemical aspects from a selected number of exciting studies based on three viral shape categories: rod, icosahedral, and filamentous. Increasing the understanding and better manipulation of the unique advantages that each category of viruses offers has led to distinct nanomaterials and applications; polymeric conducting nanofibers from rod‐shaped tobacco mosaic virus (TMV), catalytically active nanoparticles with highly controlled sizes from cowpea chlorotic mosaic virus (CCMV), and biopanning‐based affinity selection from M13 bacteriophage libraries, to name a few. Such novel materials from these bottom‐up assembly approaches are starting to show performances and capabilities beyond or impossible to be achieved via traditional materials, top‐down approaches, and inorganic devices.
Molecular Devices: Molecular Machinery
Authors: Zhang Mingming , Zhu Kelong , Huang Feihe 
Published: February 2012

Abstract
According to the driving forces, molecular machines can be easily divided into chemically driven molecular machines, electrochemically driven molecular machines, photo‐driven molecular machines and molecular machines driven by combination of two or more of them. In this chapter, we will demonstrate these four types of molecular machines in detail.
Photoswitching Materials
Authors: Ko Chi‐Chiu , Wing‐Wah Yam Vivian 
Published: February 2012

Abstract
Photoswitchable materials are mainly engineered from molecules that are capable of undergoing reversible changes in their intrinsic properties through the use of light as an external stimulus. As the absorption properties of most of these molecules change reversibly with photoexcitation, most of them are also photochromic materials. Many of these photoswitching processes operate through reversible chemical transformations, such as trans‐cis isomerization, ionization, pericyclic ring‐opening and ring‐closing reaction, and intramolecular group transfer reaction. Through systematic investigations and subsequent rational designs on the photochromic frameworks using the state‐of‐the‐art organic synthetic methodologies, the photochromic properties could be modified, tuned, and tailored for molecular switching. In this chapter, different photochromic families and selected recent works dealing with the functionalization of different families of photochromic molecules for the photoswitching of luminescent behavior, electronic communication, optical properties, molecular shuttling, and host‐guest interaction are described.
Magnetic Resonance Imaging Contrast Agents
Authors: Bonnet Célia S. , Tóth Éva 
Published: February 2012

AbstractMagnetic resonance imaging is one of the most efficient diagnostic modalities in clinical radiology and biomedical research. To enhance image contrast, paramagnetic complexes, mainly Gd3+chelates, are used. In recent years, molecular imaging has emerged as a new area aiming at noninvasive visualization of expression and function of bioactive molecules at the cellular level. This chapter is devoted to the description of supramolecular approaches in the development of highly efficient and smart contrast agents. We demonstrate via representative examples (micellar systems, liposomes, protein‐bound chelates, etc.) how supramolecular approaches are applied to increase the efficacy of Gd3+‐based contrast agents. We also include an introduction to chemical exchange saturation transfer (CEST) agents and show how supramolecular systems, such as liposomes, can be beneficial to decrease the sensitivity limit of CEST detection. Supramolecular assemblies offer an important advantage regarding the metabolic fate. While covalent polymers are excreted slowly from the body, supramolecular systems facilitate the body elimination via the excretion pathway of the small constituents. Finally, we discuss molecular imaging probes that provide an MRI response mainly through the modulation of supramolecular interactions to various biochemical variables, such as pH, temperature, metal ions, and enzymes.
Concepts and Nomenclature in Chemical Crystallography
Authors: Barbour Leonard J. , Das Dinabandhu , Jacobs Tia , Lloyd Gareth O. , Smith Vincent J. 
Published: February 2012

AbstractThe concepts relating to the structures and properties of crystals involve numerous terms that might be especially bewildering to the nonspecialist. Many of these terms have been borrowed and/or adapted from mineralogy, a much older branch of crystallography and involving a different community of researchers, while others have been coined at will to describe either new concepts or concepts for which suitable terms did not exist before. As a result, crystallographic nomenclature is far from systematic and the lexicon of modern crystallography has evolved as a haphazard collection of terms. This contribution presents a survey of the concepts that arise during the crystallographic studies of crystals, with the rather ambitious goal of achieving disambiguation regarding nomenclature. The authors specifically discuss terms that they have identified as being highly relevant to modern chemical crystallography.
The Cambridge Structural Database System and Its Applications in Supramolecular Chemistry and Materials Design
Authors: Pidcock Elna , Chisholm James A. , Wood Peter A. , Galek Peter T.A. , Fábián László , Korb Oliver , Cruz‐Cabeza Aurora J. , Liebeschuetz John W. , Groom Colin R. , Allen Frank H. 
Published: February 2012

AbstractThe Cambridge Structural Database (CSD) now records data from more than half a million small‐molecule organic and metal‐organic crystal structures. Together with the database, the complete CSD System comprises (i) software for interrogating all information fields, including 2D and 3D substructure searching, (ii) structure visualization, (iii) analysis of retrieved geometrical information, and (iv) knowledge‐based libraries of intramolecular and intermolecular information. An Internet portal to the CSD is also available. The Mercury structure visualizer is now being onwardly developed with functionality that will aid crystal engineers, supramolecular chemists, and drug development and formulation scientists. The Materials module of Mercury incorporates tools for motif topology searches and crystal packing feature searches, as well as for evaluating crystal packing similarity and for H‐bond propensity analysis, all of which are described and illustrated. It is also shown that CSD‐related software developed for drug discovery has important applications in supramolecular chemistry and crystal engineering and, conversely, that the materials development tools can benefit drug designers. Two final sections illustrate how the CSD can be used to derive predictive descriptors of cocrystal formation, and stress the importance of CSD information in the various stages of computational crystal structure prediction.
Synthetic Clathrate Systems
Authors: Bishop Roger 
Published: February 2012

AbstractClathrate compounds traditionally were discovered by happy accident because of the considerable difficulty in predicting and controlling weak intermolecular forces in crystal engineering. This chapter surveys and analyzes the various approaches taken to obtain synthetic organic clathrates, ranging from modification of a known lead compound to the design of an entirely new host from first principles. The clathrate literature has been categorized into a series of recognizable families. The individual members of these families have certain structural characteristics that define their membership. These common features are described and their functions are analyzed in supramolecular terms. Once identified, these key characteristics can then be retained during the synthesis of new family members. A number of clathrand hosts are known that contain structural features associated with two or more of the basic clathrate families. These compounds are described and their relationship with multiple host families is delineated. Finally, the chapter examines the current state of play in this research area. Recent advances and current difficulties are highlighted.
Network and Graph Set Analysis
Authors: Öhrström Lars R. 
Published: February 2012

AbstractIn this chapter, it is first shown how a number of steps in the scientific process in this field of chemistry can be improved by naming and understanding the topology of three‐dimensional networks and can be the coordination polymers, metal–organic frameworks, or hydrogen bonded systems. Specifically, the discussion is centered on the use of network analysis and graph set analysis to (i) understand the products we get, (ii) compare these materials to what others have made, (iii) communicate our results to colleagues, and (iv) truly make something new by design. The topology symbols by O'Keeffe, Wells, and others are introduced, and the reader is given a step‐by‐step guide on how to obtain the topology of a 3D net. Finally, graph set analysis is introduced, and its utility in supramolecular chemistry and network analysis discussed.
Zeolitelike Metal–Organic Frameworks (
ZMOFs
): Design, Structure, and Properties
Authors: Alkordi Mohamed H. , Eddaoudi Mohamed 
Published: February 2012

Abstract

The quest for functional materials targeted at specific applications is ever increasing as societal needs and demands mount with advancing technology. One class of inorganic‐organic hybrid materials, metal‐organic materials (MOMs), has burgeoned in recent years due, in part, to effective design strategies (e.g., reticular chemistry) for their synthesis and their inherent (and readily interchangeable) hybrid, highly functional character. The molecular building block (MBB) approach introduces the ability to generate rigid and directional building blocks, mostly
in situ
, for the construction of MOMs having specific underlying networks and/or targeted functions/properties. Various MBBs can be targeted and utilized in the assembly of functional MOMs: (i) single‐metal‐ion‐based MBBs, which promote rational construction, by forcing rigidity and directionality through control of the metal coordination sphere and judicious selection of suitable heterofunctional (N‐, O‐coordination) organic ligands, of porous MOMs with extralarge cavities, including zeolitelike metal‐organic frameworks (ZMOFs); (ii) multinuclear metal‐cluster‐based MBBs, where, for example, simple metal‐carboxylate clusters possess multiple metal‐oxygen coordination bonds that result in the generation of rigid nodes with fixed geometry that, when combined with organic ligands of specific geometry, lead to the construction of desired MOMs; and (iii) supermolecular building blocks (SBBs), which involve enhanced built‐in directional and structural information (e.g., high degree of symmetry and connectivity) compared to simple MBBs and allow the construction of high‐connectivity nets (e.g., rht‐MOFs). The MBB approach and associated strategies, as well as physical properties of some corresponding MOMs, are presented.
Supramolecular Isomerism
Authors: Bourne Susan A. 
Published: February 2012

AbstractSupramolecular isomers comprise network structures that have identical chemical compositions but differ from one another in their structure. In some instances, the term is also used to describe identical frameworks that contain different counterions, solvent, or guest molecules. Supramolecular isomerism can be observed in both molecular and coordination compounds. Like polymorphism, it results when different, but energetically similar, packing interactions can operate during crystallization.Gaining control on crystallization of a particular isomer remains challenging as both thermodynamic and kinetic factors play a role, and as understanding the full energy profile of a self‐assembly process is extremely difficult. Some important variables within the crystallization system have been identified, including chemical and physical factors, which are described in this chapter.Supramolecular isomers may be considered in four categories: structural, conformational, interpenetrated, and chiral networks. Examples of each are provided. A number of topological approaches have been described over the years, which aid in the description of extended structures. Both graph set and network analyses are useful for this purpose.Crystal engineering aims to control structural characteristics of crystalline materials, with the aim of having greater control over their physical properties. Although hydrogen‐bonded supramolecular synthons have been studied in depth for more than a decade and although coordination bonds are stronger and more directional than other supramolecular interactions, structural uncertainty is still a characteristic of self‐assembled systems. Some structure‐property relationships are emerging, including luminescence and porosity.
Interpenetration
Authors: Batten Stuart R. 
Published: February 2012

Abstract

Interpenetration of multiple polymeric networks is an important and widespread phenomenon in crystal engineering. A thorough understanding of not just network topology but also interpenetration topology (i.e., the way networks interpenetrate) is therefore vital. 1D and 2D networks can interpenetrate in either a parallel or an inclined manner, leading to overall entanglements of the same or higher dimensions. This can be summarized using the notation
m
D(/
n
D) →
p
D parallel/inclined interpenetration. For example, parallel interpenetration of 2D nets leading to an overall 3D entanglement is 2D → 3D parallel interpenetration. Within each of these subclasses, there are also many different possible interpenetration topologies, as there are for the interpenetration of 3D networks. Interpenetration of networks that are chemically, topologically, and even dimensionally different is rare but possible. Self‐penetration occurs when the smallest topological rings of a network are penetrated by rods from the same network.
Crystal Growth and Molecular Crystal Growth Modification
Authors: Jones Franca , Ogden Mark I. 
Published: February 2012

Abstract

Crystals have been described as the supermolecule
par excellence
, and hence it is important to have an understanding of how crystals grow and how to control the growth processes. The fundamentals of crystal growth are discussed, including recent developments such as two‐step nucleation theory and the concept of mesocrystals. The mesocrystals are formed by the aligned assembly of nanoparticles, and lead to products that are difficult, in some cases, to differentiate from genuine single crystals. The many different mechanisms by which impurities and additives can influence crystal growth are given, with an emphasis on the complexity associated with studying these systems. The control of crystal growth using tailor‐made additives is described, with particular application to molecular crystal systems. Examples focus on glycine, and include morphology control, determination of absolute configuration of a molecule, determination of crystal polarity, and polymorph control.
Multicomponent Self‐Assembled Polymers Based on π‐Conjugated Systems
Authors: Kaeser Adrien , Wolffs Martin , Schenning Albertus P. H. J. 
Published: February 2012

Abstract
The present chapter focuses on the most significant developments in the organization of multicomponent π‐conjugated molecules into supramolecular polymers. The different approaches to prepare these structures are presented and classified into the different types of supramolecular organizations that are obtained by simple mixing or by using a multistep methodology.
Self‐Healing and Mendable Supramolecular Polymers
Authors: Burattini Stefano , Colquhoun Howard M. , Greenland Barnaby W. , Hayes Wayne 
Published: February 2012

Abstract
This chapter reviews the recent development of self‐healing and easily mendable polymeric materials in which designed supramolecular interactions—notably hydrogen bonding, metal–ligand coordination, and complementary aromatic π−π‐stacking—play key roles. Factors such as molecular weight, association constants for key binding motifs, kinetic lability of binding interactions, compatibility of blended materials, extent of microphase separation, and degree of crystallinity are discussed with reference to the balance of polymer properties and achievement of healable characteristics. Supramolecular polymer systems that undergo spontaneous healing under specific damage conditions (e.g., projectile‐impact) are described, as are those which require some form of stimulus to initiate the healing process.
Molecularly Imprinted Polymers
Authors: Sellergren Börje , Hall Andrew J. 
Published: February 2012

AbstractMolecular imprinting—or templating at a molecular level—allows the preparation of synthetic polymers featuring receptor or catalytically active sites. The most common form of imprinting comprises the synthesis of reticulated polymers in the presence of templates which, widely defined, may range from ions and small molecules to biological macromolecules and ultimately microorganisms. Functional monomers act as anchors interacting with the template and holding it in place during the polymerization. Removal of the template from the formed polymer liberates binding sites complementary in shape and binding groups to the template structure. This review starts by outlining the main synthetic concepts underlying the design of imprinted polymers and thereafter highlights key contributions devoted to various molecular recognition‐based applications.
Supramolecular Chemistry in Polymer Networks
Authors: Besenius Pol , Cormack Peter A. G. 
Published: February 2012

AbstractCross‐linked organic materials or polymer networks have found numerous applications and technologies that are indispensable in everyday life. Networks formed via molecular recognition events that act as noncovalent cross‐linkers exhibit rather unusual properties due to the dynamic character and tunable strength of the supramolecular interactions. In the first instance, we aim to introduce and discuss complementary functional groups that have been developed to allow for reversible network formation in bulk supramolecular materials. Thereafter, this chapter deals mainly with network formation in macroscopic and particulate gels. In both parts, we highlight how material properties at the meso‐ and macroscopic scales are governed by noncovalent forces on the molecular level, and how supramolecular interactions can offer opportunities in the fabrication of stimuli‐responsive materials. Lead examples and applications are highlighted throughout, for example, in the development of thermoplastic elastomers, coatings, tissue engineering, and drug delivery technologies.
Physisorption for Self‐Assembly of Supramolecular Systems: A Scanning Tunneling Microscopy Perspective
Authors: Mali Kunal S. , Adisoejoso Jinne , De Cat Inge , Balandina Tanya , Ghijsens Elke , Guo Zongxia , Li Min , Sankara Pillai Mahesh , Vanderlinden Willem , Xu Hong , De Feyter Steven 
Published: February 2012

Abstract
The objective of this chapter is to provide a brief account of the progress in the understanding of physisorbed monolayers through illustration of some key examples from contemporary literature. The discussion is limited to the self‐assembly of weakly adsorbed molecules at the liquid–solid interface as studied by scanning probe microscopy methods, especially scanning tunneling microscopy (STM). The fundamental aspects governing the formation and stabilization of physisorbed monolayers at the liquid–solid interface, such as influence of substrate, solvent, and temperature are highlighted. Special attention is also given to template‐directed self‐assembly, nanoporous and multicomponent surface networks, as well as surface chirality. Apart from its utility as a valuable tool to visualize matter down to atomic scale, the role of STM in comprehending fundamental physical and chemical phenomena such as molecular dynamics, electronics, and reactivity is also reviewed. This chapter could be equally appealing to both industry as well as academia since physisorbed monolayers at liquid–solid interfaces play a very important role in a number of industrially relevant processes and are also of intense academic interest due to the possibilities in surface nanoengineering and functionalization.
Chemisorbed Self‐Assembled Monolayers
Authors: Azzaroni Omar , Salvarezza Roberto C. 
Published: February 2012

Abstract
A review of the fundamental aspects of chemisorbed self‐assembled monolayers (SAMs), as a tool for building complex molecular systems on solid surfaces, is presented. Using alkanethiols, SAMs, as model systems the self‐assembly, surface structures, and SAM stability under different experimental conditions are discussed. We also point out the characteristics of SAMs that make them suitable especially for building active micro‐ and nanostructured molecular systems on surfaces, and stress their limitations resulting from defects, contaminants, and disorder. Finally, we show examples of interfacial architectures drawn from supramolecular and covalent systems to illustrate the potential of SAMs as robust platforms for building functional 3D structures on solid substrates.