Jürg Hulliger

Bio: Jürg Hulliger is an academic researcher from University of Bern. The author has contributed to research in topics: Polarity (physics) & Raman scattering. The author has an hindex of 34, co-authored 211 publications receiving 5243 citations. Previous affiliations of Jürg Hulliger include Ludwig Maximilian University of Munich & Delft University of Technology.

Organic fluorine compounds: a great opportunity for enhanced materials properties.

Abstract: Interactions of “organic fluorine” have gained great interest not only in the context of crystal engineering, but also in the systematic design of functional materials. The first part of this tutorial review presents an overview on interactions known by organic fluorine. This involves π–πF, C–F⋯H, F⋯F, C–F⋯πF, C–F⋯π, C–F⋯M+, C–F⋯CO and anion–πF interactions, as well as other halogen bonds. The effect of the exchange of H vs. F is discussed by means of several examples and a short introduction to the young field of “fluorous” chemistry is given. The second part is dedicated to numerous applications of fluorine and fluorous interactions. It is shown how application of fluorination is used to enable a number of reactions, to improve materials properties and even open up new fields of research.

Fluorine in crystal engineering—“the little atom that could”

Abstract: In the last decade interactions of fluorine substituents in a variety of organic compounds have gained interest in life science and solid state materials. This review provides knowledge on fluorine interactions classified into phenyl–perfluorophenyl-, C–F⋯H, F⋯F and C–F⋯πF interactions. Except for phenyl–perfluorophenyl stacking featuring a stabilising energy of about 30 kJ·mol−1, interactions involving fluorine are generally weak. Although, there is still no concise understanding of fluorine interactions, there are numerous examples showing the influence of weak synthons on chemical, physical and biological properties.

Nanoporous and mesoporous organic structures: new openings for materials research

Abstract: Organic solid state and molecular architectures providing nano- or mesoporous space for the inclusion of guest species open up new opportunities for the synthesis of materials showing designed chemical and physical properties. Porous materials are reviewed by taking into account recent progress in inorganic zeolites, metalloorganic and organic networks including carbon nanotubes and condensed cyclodextrins. Various properties requiring a parallel alignment of close-packed guests are addressed. As a particular example of physical property design, spontaneous polarity formation in channel-type inclusion compounds is discussed.

Chemistry and crystal growth

Abstract: Single-crystal materials, along with other forms of condensed matter (ceramics, polymers, liquid crystals, etc.) are fundamental to modern technology. The basic research and production of new materials with “tailored” solid-state physical properties therefore necessitate not only chemical synthesis but also the production of single crystals of a particular morphology (either bulk or thin layer crystals) and well-defined crystal defects (doping). In this review, an attempt is made to broaden the traditional synthetic concept of chemistry to the process of single-crystal synthesis. The methods of the resulting approach, which takes into account the specific properties of solid materials, are discussed and illustrated by experimental set-ups for the solution of a range of problems in chemical crystallization. Also included is recent work on the growing of single crystals of high-temperature superconductors, organic non-linear optical compounds, and proteins.

Magnetic separation: its application in mining, waste purification, medicine, biochemistry and chemistry

Abstract: The use of strong magnetic field gradients and high magnetic fields generated by permanent magnets or superconducting coils has found applications in many fields such as mining, solid state chemistry, biochemistry and medical research. Lab scale or industrial implementations involve separation of macro- and nanoparticles, cells, proteins, and macromolecules down to small molecules and ions. Most promising are those attempts where the object to be separated is attached to a strong magnetic nanoparticle. Here, all kinds of specific affinity interactions are used to attach magnetic carrier particles to mainly objects of biological interest. Other attempts use a strong paramagnetic suspension for the separation of purely diamagnetic objects, such as bio-macromolecules or heavy metals. The application of magnetic separation to superconducting inorganic phases is of particular interest in combination with ceramic combinatorial chemistry to generate a library of e.g. cuprate superconductors.

Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

Abstract: Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

Upconversion and Anti-Stokes Processes with f and d Ions in Solids

Abstract: Before the 1960s, all anti-Stokes emissions, which were known to exist, involved emission energies in excess of excitation energies by only a few kT. They were linked to thermal population of energy states above excitation states by such an energy amount. It was the well-known case of anti-Stokes emission for the so-called thermal bands or in the Raman effect for the well-known anti-Stokes sidebands. Thermoluminescence, where traps are emptied by excitation energies of the order of kT, also constituted a field of anti-Stokes emission of its own. Superexcitation, i.e., raising an already excited electron to an even higher level by excited-state absorption (ESA), was also known but with very weak emissions. These types of well-known anti-Stokes processes have been reviewed in classical textbooks on luminescence.1 All fluorescence light emitters usually follow the well-known principle of the Stokes law which simply states that excitation photons are at a higher energy than emitted ones or, in other words, that output photon energy is weaker than input photon energy. This, in a sense, is an indirect statement that efficiency cannot be larger than 1. This principle is

Engineering coordination polymers towards applications

Abstract: The development in the field of coordination polymers or metal-organic coordination networks, MOCNs (metal-organic frameworks, MOFs) is assessed in terms of property investigations in the areas of catalysis, chirality, conductivity, luminescence, magnetism, spin-transition (spin-crossover), non-linear optics (NLO) and porosity or zeolitic behavior upon which potential applications could be based.

The Halogen Bond

Abstract: 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.