Volume 3, Issue 12 -

Changing demands on the energy landscape are causing the need for sustainable approaches. The shift toward alternative, renewable energy sources is closely associated with new demands for energy storage and transportation. Besides storage of electrical energy, also storage of energy by generating and consuming hydrogen (H 2 ) is possible and highly attractive. Notably, both secondary energy vectors, electric energy and hydrogen, have practical advantages so that one should not ask “which one is better?” but “which one fits better the specific application?” Molecular hydrogen can be stored reversibly in form of formic acid (FA, HCOOH). In the presence of suitable catalysts, FA can be selectively decomposed to hydrogen and carbon dioxide (CO 2 ). A CO 2 -neutral hydrogen storage cycle can be achieved when carbon dioxide serves as starting material for the production of the FA. Examples of CO 2 hydrogenation to FA are known in the literature. Herein, the formal reverse reaction, the decomposition of FA to H 2 and CO 2 by different catalyst systems is reviewed and selected examples for reversible storage applications based on FA as hydrogen storage compound are discussed.

The biological pre-validation of natural products (NPs) and their underlying frameworks ensures an unrivaled source of inspiration for chemical probe and drug design. However, the poor knowledge of their drug target counterparts critically hinders the broader exploration of NPs in chemical biology and molecular medicine. Cutting-edge algorithms now provide powerful means for the target deconvolution of phenotypic screen hits and generate motivated research hypotheses. Herein, we present recent progress in artificial intelligence applied to target identification that may accelerate future NP-inspired molecular medicine.

In its simplest form, green chemistry may be defined as the design of chemical products and processes that reduce or eliminate the generation of hazardous substances. The brief history of green chemistry is marked with extraordinary creativity and accomplishments in meeting the “triple bottom line” of sustainability in economic, social, and environmental performance. Green chemistry is about redesigning chemical processes from the ground up, and it goes hand in hand with the sustainable practice of chemistry. We need to start at the undergraduate level, and to provide a better foundation in green chemistry and systems thinking if we are to prepare a generation of chemists able to respond to the grand challenges of sustainability.

Organoselenolates, due to the high polarizability of the chalcogen atoms, are generally weak bases and soft nucleophiles used to introduce in stereoselective and mild way a selenium functionality through substitution or addition reactions. Among several methods reported for their preparation, recently the reduction of Se-Se or Se-Halogen bond mediated by elemental zinc becomes particularly attractive for the simplicity and the efficiency of the protocols. An overview on the most recent developments in the field is here reported.

An O 2 -electrode was fabricated using a metal ion implanted SrTiO 3 single crystal. The time resolved oxygen exchange rate of ion implanted strontium titanate (SrTiO 3 ) single crystals was studied by means of oxygen solid electrolyte coulometry (OSEC). Transmission electron microscopy (TEM) was performed in order to determine structural changes after ion implantation. Moreover, theoretical modelling based on defect chemistry under equilibrium conditions was applied for determining of effective rate constants. OSEC measurements turn out to be a damage and calibration free method, which was used for the first time in order to characterize kinetic parameters of oxygen exchange on single crystalline surfaces.

Mastery over the size/shape of nanocrystals (NCs) enables control of their properties and enhancement of their usefulness for a given application. Within the past decades, the development of wet-chemistry methods leads to the blossom of research in noble metal nanomaterials with tunable sizes and shapes. We herein would prefer to devote this chapter to introduce the solution-based methods for size and shape-controlled synthesis of ruthenium (Ru) NCs, which can be summarized into five categories: (i) Synthesis of spherical Ru NCs; (ii) synthesis of one-dimensional (1D) Ru NCs, e.g. wires and rods; (iii) synthesis of two-dimensional (2D) Ru NCs, e.g. nanoplates; (iv) synthesis of Ru NCs with hollow interiors and (v) synthesis of Ru NCs with other morphologies, e.g. chains, dendrites and branches. We aim at highlighting the synthetic approaches and growth mechanisms of these types of Ru NCs. We also introduce the detailed characterization tools for analysis of Ru NCs with different sizes/shapes. With respect to the creation of great opportunities and tremendous challenges due to the accumulation in noble metal nanomaterials, we briefly make some perspectives for the future development of Ru NCs so as to provide the readers a systematic and coherent picture of this promising field. We hope this reviewing effort can provide for technical bases for effectively designing and producing Ru NCs with enhanced physical/chemical properties. Graphical Abstract : The solution-based methods for size and shape-controlled synthesis of ruthenium nanocrystals as well as the mechanisms behind them are extensively reviewed.

Selenium and tellurium form binary halides in which the chalcogen can be in formal oxidation states (IV), (II) or (I). They are versatile reagents for the preparation of a wide range of inorganic and organic selenium and tellurium compounds taking advantage of the reactivity of the chalcogen–halogen bond. With the exception of the tetrafluorides, the tetrahalides are either commercially available or readily prepared. On the other hand, the low-valent species, EX 2 (E = Se, Te; X = Cl, Br) and E 2 X 2 (E = Se, Te; X = Cl, Br) are unstable with respect to disproportionation and must be used as in situ reagents. Organoselenium and tellurium halides are well-known in oxidation states (IV) and (II), as exemplified by REX 3 , R 2 EX 2 and REX (R = alkyl, aryl; E = Se, Te; X = F, Cl, Br, I); mixed-valent (IV/II) compounds of the type RTeX 2 TeR are also known. This chapter surveys the availability and/or preparative methods for these widely used reagents followed by examples of their applications in synthetic inorganic and organic selenium and tellurium chemistry. For both the binary halides and their organic derivatives, the discussion is subdivided according to the formal oxidation state of the chalcogen.