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While hydrogen plays an ever-increasing role in modern society, nature has utilized hydrogen since a very long time as an energy carrier and storage molecule. Among the enzymatic systems that metabolise hydrogen, [FeFe]-hydrogenases are one of the most powerful systems to perform this conversion. In this light, we will herein present an overview on developments in [FeFe]-hydrogenase research with a strong focus on synthetic mimics and their application within the native enzymatic environment. This review spans from the biological assembly of the natural enzyme and the highly controversial discussed mechanism for the hydrogen generation to the synthesis of multiple mimic platforms as well as their electrochemical behaviour.

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An ideal therapeutic agent for bone diseases should act solely on bone tissue with no pharmacological activity at other anatomical sites. Current therapeutic agents, however, do not usually display a preferential affinity to bones and non-specifically distribute throughout the body after administration. Attempts to design bone-specific agents have relied on engineering a desired therapeutic agent with bone-seeking molecules so that the latter delivers the therapeutic agents specifically to bones. In this critical review , we summarize the latest attempts to engineer bone-seeking therapeutic agents based on formulating therapeutic agents with bisphosphonates, a class of compounds with high affinity to biological apatite. We first provide a relevant summary of the structure of bone mineral and bisphosphonates, highlighting the mode of interaction between these two entities. The use of bisphosphonates in the diagnosis of bone diseases is then presented, since this application helps us to understand the bone-carrier properties of bisphosphonates under physiological conditions. A summary of recent attempts to formulate bisphosphonates with traditional therapeutic agents to restrict their activities to bone tissues is then provided, with special emphasis on the structure–function relationships of the engineered compounds. Finally, attempts to use bisphosphonates to deliver macromolecular therapeutics ( i.e. , proteins) are summarized, based on recent data from the authors' lab. The collective research into bone-seeking medicinal agents is progressively laying the foundation for next-generation ‘magic bullets’ that display desirable activities at the disease sites with no undesirable activity on other organ systems. (164 references.)

This article reviews the state of the art in the development of strategies for generating supramolecular systems for dynamic cell studies. Dynamic systems are crucial to further our understanding of cell biology and are consequently at the heart of many medical applications. Increasing interest has therefore been focused recently on rendering systems bioactive and dynamic that can subsequently be employed to engage with cells. Different approaches using supramolecular chemistry are reviewed with particular emphasis on their application in cell studies. We conclude with an outlook on future challenges for dynamic cell research and applications.

Cycloaddition reactions have been employed in polymer synthesis since the mid-nineteen sixties. This critical review will highlight recent notable advances in this field. For example, [2 + 2] cycloaddition reactions have been utilized in numerous polymerizations to enable the construction of strained polymer systems such as poly(2-azetidinone)s that can, in turn, afford polyfunctional β-amino acid derived polymers. Polymers have also been synthesized successfully via (3 + 2) cycloaddition methods utilizing both thermal and high-pressure conditions. ‘Click chemistry’ – a process involving the reaction of azides with olefins, has also been adopted to generate linear and hyperbranched polymer architectures in a very efficient manner. [4 + 2] Cycloadditions have also been utilized under thermal and high-pressure conditions to produce rigid polymers such as polyimides and polyphenylenes. These cycloaddition polymerization methods afford polymers with potential for use in high performance polymers applications such as high temperature resistant coatings and polymeric organic light emitting diodes.

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Alkoxyallenes are unusually versatile C3 building blocks in organic synthesis. Hence this tutorial review summarizes the most important transformations, including subsequent reactions and their applications in the synthesis of relevant compounds, e.g. natural products. The reactivity patterns involved and the synthons derived from alkoxyallenes are presented. Often alkoxyallenes can serve as substitutes of acrolein or acrolein acetals, utilisation of which has already led to interesting products. Most important is the use of lithiated alkoxyallenes which smoothly react with a variety of electrophiles and lead to products with unique substitution patterns. The heterocycles or carbocycles formed are intermediates for the stereoselective synthesis of natural products or for the preparation of other structurally relevant compounds. The different synthons being put into practice by the use of lithiated alkoxyallenes in these variations will be discussed.

The purpose of this review is to demonstrate advances, challenges and perspectives of quantum chemical approaches in molecular spectroscopy of the condensed phase. Molecular spectroscopy, particularly vibrational spectroscopy and electronic spectroscopy, has been used extensively for a wide range of areas of chemical sciences and materials science as well as nano- and biosciences because it provides valuable information about structure, functions, and reactions of molecules. In the meantime, quantum chemical approaches play crucial roles in the spectral analysis. They also yield important knowledge about molecular and electronic structures as well as electronic transitions. The combination of spectroscopic approaches and quantum chemical calculations is a powerful tool for science, in general. Thus, our article, which treats various spectroscopy and quantum chemical approaches, should have strong implications in the wider scientific community. This review covers a wide area of molecular spectroscopy from far-ultraviolet (FUV, 120–200 nm) to far-infrared (FIR, 400–10 cm ?1 )/terahertz and Raman spectroscopy. As quantum chemical approaches, we introduce several anharmonic approaches such as vibrational self-consistent field (VSCF) and the combination of periodic harmonic calculations with anharmonic corrections based on finite models, grid-based techniques like the Numerov approach, the Cartesian coordinate tensor transfer (CCT) method, Symmetry-Adapted Cluster Configuration-Interaction (SAC-CI), and the ZINDO (Semi-empirical calculations at Zerner's Intermediate Neglect of Differential Overlap). One can use anharmonic approaches and grid-based approaches for both infrared (IR) and near-infrared (NIR) spectroscopy, while CCT methods are employed for Raman, Raman optical activity (ROA), FIR/terahertz and low-frequency Raman spectroscopy. Therefore, this review overviews cross relations between molecular spectroscopy and quantum chemical approaches, and provides various kinds of close-reality advanced spectral simulation for condensed phases.

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BACE1 (β-secretase, memapsin 2, Asp2) has emerged as a promising target for the treatment of Alzheimer's disease. BACE1 is an aspartic protease which functions in the first step of the pathway leading to the production and deposition of amyloid-β peptide (Aβ). Its gene deletion showed only mild phenotypes. BACE1 inhibition has direct implications in the Alzheimer's disease pathology without largely affecting viability. However, inhibiting BACE1 selectively in vivo has presented many challenges to medicinal chemists. Since its identification in 2000, inhibitors covering many different structural classes have been designed and developed. These inhibitors can be largely classified as either peptidomimetic or non-peptidic inhibitors. Progress in these fields resulted in inhibitors that contain many targeted drug-like characteristics. In this review, we describe structure-based design strategies and evolution of a wide range of BACE1 inhibitors including compounds that have been shown to reduce brain Aβ, rescue the cognitive decline in transgenic AD mice and inhibitor drug candidates that are currently in clinical trials.