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

The stability of two-dimensional (2D) layers and membranes is subject of a long standing theoretical debate. According to the so called Mermin-Wagner theorem, long wavelength fluctuations destroy the long-range order for 2D crystals. Similarly, 2D membranes embedded in a 3D space have a tendency to be crumpled. These dangerous fluctuations can, however, be suppressed by anharmonic coupling between bending and stretching modes making that a two-dimensional membrane can exist but should present strong height fluctuations. The discovery of graphene, the first truly 2D crystal and the recent experimental observation of ripples in freely hanging graphene makes these issues especially important. Beside the academic interest, understanding the mechanisms of stability of graphene is crucial for understanding electronic transport in this material that is attracting so much interest for its unusual Dirac spectrum and electronic properties. Here we address the nature of these height fluctuations by means of straightforward atomistic Monte Carlo simulations based on a very accurate many-body interatomic potential for carbon. We find that ripples spontaneously appear due to thermal fluctuations with a size distribution peaked around 70 \AA which is compatible with experimental findings (50-100 \AA) but not with the current understanding of stability of flexible membranes. This unexpected result seems to be due to the multiplicity of chemical bonding in carbon.

Intrinsic ripples in graphene

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in ...

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine.

Kinetic of crystallization from the melt and chain folding in polyethylene fractions revisited: theory and experiment

Crystallization behavior of nylon 6 nanocomposites

High-performance nanocomposites based on polyetherketones

Development and characterization of PEEK/carbon nanotube composites

Opportunities and challenges in the use of inorganic fullerene-like nanoparticles to produce advanced polymer nanocomposites

Structure and thermal properties of blends of nylon 6 and a liquid crystal copolyester

The nucleation activity of the sorbitol derivatives 1,2,3,4-bis(3,4-dimethylbenzylidene sorbitol) and methyldibenzylidene sorbitol are compared with that of talc, a conventional nucleating agent for the monoclinic crystalline phase of isotactic polypropylene. The thermal parameters associated with the dynamic crystallization process are studied as a function of the cooling rate by differential scanning calorimetry, and the nucleating efficiency is assessed by comparison with self-nucleation, the highest values being observed for 1,2,3,4-bis(3,4-dimethylbenzylidene sorbitol) over the whole concentration range. The nature of the polymer crystals formed in the nucleated polymer was studied by X-ray diffraction, and the data show an increase in a preferred orientation of the polymer crystallites with increasing concentration of nucleating agent. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2440–2450, 2002

Carlos Marco

Papers

High-performance nanocomposites based on polyetherketones

Development and characterization of PEEK/carbon nanotube composites

Opportunities and challenges in the use of inorganic fullerene-like nanoparticles to produce advanced polymer nanocomposites

Structure and thermal properties of blends of nylon 6 and a liquid crystal copolyester

Comparative study of the nucleation activity of third‐generation sorbitol‐based nucleating agents for isotactic polypropylene