J. Appl. Cryst.の発刊に際して

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

The Halogen Bond

Halogen bonding is the noncovalent interaction where halogen atoms function as electrophilic species. The energetic and geometrical features of the interaction are described along with the atomic characteristics that confer molecules with the specific ability to interact through this interaction. Halogen bonding has an impact on all research fields where the control of intermolecular recognition and self-assembly processes plays a key role. Some principles are presented for crystal engineering based on halogen-bonding interactions. The potential of the interaction is also shown by applications in liquid crystals, magnetic and conducting materials, and biological systems.

Halogen Bonding in Supramolecular Chemistry

Supramolecular materials, dynamic materials by nature, are defined as materials whose components are bridged via reversible connections and undergo spontaneous and continuous assembly/disassembly processes under specific conditions. On account of the dynamic and reversible nature of noncovalent interactions, supramolecular polymers have the ability to adapt to their environment and possess a wide range of intriguing properties, such as degradability, shape-memory, and self-healing, making them unique candidates for supramolecular materials. In this critical review, we address recent developments in supramolecular polymeric materials, which can respond to appropriate external stimuli at the fundamental level due to the existence of noncovalent interactions of the building blocks.

Stimuli-responsive supramolecular polymeric materials.

Surface-initiated controlled polymerization as a convenient method for designing functional polymer brushes: From self-assembled monolayers to patterned surfaces

Halogenbrucken sind nichtkovalente Wechselwirkungen, in denen Halogenatome als elektrophile Spezies auftreten. Die Energien und geometrischen Charakteristika derartiger Bindungen werden im vorliegenden Kurzaufsatz beschrieben, und es wird diskutiert, welche Voraussetzungen Molekule erfullen mussen, um diese Wechselwirkungen eingehen zu konnen. Die Bildung von Halogenbrucken wirkt sich auf alle Forschungsgebiete aus, die durch molekulare Erkennung und Selbstorganisation bestimmt sind. Es werden einige Prinzipien fur das Kristall-Engineering mithilfe von Halogenbrucken vorgestellt. Das Potenzial derartiger Wechselwirkungen zeigt sich auch in Flussigkristallen, magnetischen und leitfahigen Materialien sowie in biologischen Systemen.

Halogenbrücken in der supramolekularen Chemie

Engineering functional materials endowed with unprecedented properties require the exploitation of new intermolecular interactions, which can determine the characteristics of the bulk materials. The great potential of Halogen Bonding (XB), namely any noncovalent interaction involving halogens as electron acceptors, in the design of new and high-value functional materials is now emerging clearly. This Highlight will give a detailed overview on the energetic and geometric features of XB, showing how some of them are quite constant in most of the formed supramolecular complexes (e.g., the angle formed by the covalent and the noncovalent bonds around the halogen atom), while some others depend strictly on the nature of the interacting partners. Then, several specific examples of halogen-bonded supramolecular architectures, whose structural aspects as well as applications in fields as diverse as enantiomers' separation, crystal engineering, liquid crystals, natural, and synthetic receptors, will be fully described. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: PolymChem 45: 1–15, 2007

https://onlinelibrary.wiley.com/doi/pdf/10.1002/pola.21725

Engineering functional materials by halogen bonding

Halogen bonding has recently entered the arena of reliable and valuable non-covalent interactions for the construction of supramolecular complexes. A step further, this highlight provides some new insights related to the design of advanced functional materials encompassing halogen bonded mesomorphic and electronic components. Other recent applications have been extended to various aspects of solution phase recognition (catalysis, ion sensing and resolution) and macromolecular organizations (porous, polymeric and hybrid systems).

Franck Meyer

Papers

Halogen Bonding in Supramolecular Chemistry

Surface-initiated controlled polymerization as a convenient method for designing functional polymer brushes: From self-assembled monolayers to patterned surfaces

Halogenbrücken in der supramolekularen Chemie

Engineering functional materials by halogen bonding

Halogen bonding at work: recent applications in synthetic chemistry and materials science