One-dimensional coordination FeII polymers constructed through triple N1,N2-1,2,4-triazole bridges form a unique class of spin-crossover materials, the synthetic versatility of which allows tuning the spin-crossover properties, the design of gels, films, liquid crystals, and nanoparticles and single-particle addressing. This Minireview provides the first complete overview of these very attractive switchable materials and their most recent developments.

Angewandte Chemie hot paper on Smart Materials. Complex alignment of the nematic director in liquid crystalline polymeric films has been achieved using a novel processing methodology on photoalignment layers. Free standing polymeric films with this complex director patterns deform into exotic shapes like cones and saddle-like shapes when exposed to an external stimulus like heat. This work, carried out in collaboration with the group of Prof. Dirk J. Broer (Eindhoven University of Technology, The Netherlands), experimentally corroborates the theoretical predictions from Prof. Mark Warner (University of Cambridge, United Kingdom) on Disclination-mediated stimuli response in nematic glass sheets.

Star gazing: The six-coordinate organoniobium(V) compound [NBu4]2[NbO(C6F5)5] has been found to exhibit a pentagonal-pyramidal (PPY-6) structure, which is unprecedented in organotransition-metal chemistry (see picture: complex as viewed down the O–Nb axis; C in gray, O in red, F in yellow, and Nb in blue).

Hot Article! One pot syntheses may seem like an attractive option for syntheses with multiple reaction steps but reagents are not always compatible, leading to serious reductions in yields. An alternative sequential approach has been adopted that allows several different heterogeneous catalysts to be used, producing the target compound in much higher yields than the classical approach. Three reactions are conducted in sequence by simply filtering the catalyst after each step and proceeding with the crude mixture.

N-Heterocyclic carbene (NHC) ligands have found widespread application in transition-metal catalysis and organometallic chemistry, as they offer an extraordinarily wide range of stereoelectronic possibilities. These may be further increased by combining NHCs with themselves or other donor moieties to form bi- or multidentate ligands. This work shows that one of the most commonly employed NHC ligands, 1,3- bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes), is susceptible to double cyclometalation at the coordination sphere of iridium to form the k3-C fac-coordinating ligand IMes. In addition to this stabilizing coordination mode, the new ligand offers strong trans-labilizing capabilities and can be demetalated in a stepwise fashion or functionalized using a variety of reagents.

The Kondo effect underpins a broad range of correlated electron behaviour, but is unexpected in materials with well-localized f levels. However, Kondo-like features are experimentally reported to occur for Nd impurities in LaB6 and are interpreted as the result of 4f quadrupolar degrees of freedom of the Nd crystal-field, ground-state quartet. This surprising discovery has been made in ICMA together with collaborators from the University of California, Florida State University and National High Magnetic Field Laboratory in Tallahassee.

Micropillar compression tests have become a popular research topic in recent years to study the effect of specimen size (in the range of micron and sub-micron pillar diameter) on the mechanical properties of single-crystals. The flow stress was generally found to scale with an inverse power of specimen diameter. The precise mechanisms responsible for this behavior are still a matter of debate. Usually the pillars are prepared by FIB milling, creating defects that can affect to their mechanical properties. In the paper by J. Soler et al, directional solidification of LiF-NaCl and LiF-KCl eutectics and subsequent controlled etching or the matrix (chloride) has been used to prepare forest of LiF micropillars (diameter of 1 to 5 microns). Their deformation upon uniaxial compression was studied. The flow stress increases by 30% in Ar+-irradiated micropillars. No size-effect was observed when compression was done along the [111] crystallographic direction, where there is strong resistance to dislocation motion.

New and more efficient energy conversion systems are required in the near future, due in part to the increase of oil prices and demand and also in addition due to global warming. Fuel cells and hybrid systems present a promising future but in order to cover the demand, high amounts of hydrogen will be required. Probably, the cleanest method when combined with a renewable energy source to produce hydrogen up to date is water electrolysis. In this field, Solid Oxide Electrolysis Cells (SOEC) have attracted a great interest in the last few years, as they offer significant power and higher efficiencies in comparison with conventional low temperature electrolysers. Their applications, performances and material issues will be reviewed.

Eliminating restraints: A trigonal-bipyramidal structure has been found to be the energetically favored geometry of the hypervalent AX5 molecule Sb(C6F5)5 in the solid state and also in fluid solution, where molecules move freely and no crystal packing effects operate (see picture).