ChemPlusChem

The cover picture shows the release of the luminescent rhenium coordination complex (yellow spheres) in solution. This release is triggered by electrochemical stimulus applied through the cable to the metallopolymer, which is represented by the splash of blue paint. The irreversibility of the electrochemical release is highlighted by holes in the graph paper. G. Valenti, F. Paolucci, R. J. Forster, and co-workers outline the photophysical and electrochemical properties of a novel metallopolymer containing [Re(bpy)(CO)3]⁺ moieties coordinated to a poly(4-vinylpyridine) polymer chain in their Full Paper on page 55 ff. Release of the metal complexes can be triggered by oxidation or reduction of the rhenium complex.

“We use electrochemistry as a tool for connecting different disciplines ...” This and more about the colloboration between the groups of F. Faolucci and R. J. Forster can be found on page 2.

The frontispiece shows metal-mediated base pairing, where the hydrogen bonds present in natural base pairs are formally replaced by coordinative bonds to metal ions located along the helical axis. These base pairs can be made by introducing artificial ligand-based nucleosides into the nucleic acid sequence. In the presence of suitable transition-metal ions, these metal ions will site-specifically bind to the nucleic acid. As a result, DNA can be used as a supramolecular scaffold for metal-based functionality, adding new physical properties to this biomacromolecule. The latest developments in this field are highlighted in the Review by Philipp Scharf and Jens Müller on page 20 ff.

The frontispiece shows a bioinspired and solar-powered device for catalytic generation of fuel, the Artificial Leaf, with immobilized catalysts and light harvesting units having donor–acceptor pairs on anodic and cathodic sites separated by a proton exchange membrane. The Minireview by Khurram S. Joya, Huub J. M. de Groot, and co-workers on page 35 ff. outlines progress in the field of electrodriven water oxidation devices in relation to solar energy conversion into clean and renewable fuels. Water oxidation assemblies using single-site, binuclear, or multicenter molecular complexes and future perspective of water splitting catalysis for generation of solar fuel are also presented.

Rise of the machines: This Review presents an overview of metal-mediated base pairs. It also gives an insight into the structures of the resulting metal-modified nucleic acids (see figure). Moreover, applications exploiting the formation of metal-mediated base pairs are summarized. The applications include metal-ion sensors of various types, a protein sensor, and DNA-based molecular machines.

Splitting up: An overview of molecular catalytic assemblies for electrochemical water oxidation and an analysis of recent progress in catalyst design and performance are presented, including systems integration of modules for future stand-alone solar-to-fuel conversion devices (see figure). The thermodynamics of intermediates and the mechanism of OO bond formation are also described.

Biomimetic functionalization: CTAB-covered gold nanorods were functionalized with an engineered GBP-SpA protein through its preferential binding on the gold surface, while colloidal stability was maintained through in situ removal of free CTAB. The functionalized GNRs could be used for plasmonic biosensing after conjugation of antibody through biomolecular recognition (see picture).

Well-oiled machine: Micro and macroscale self-assembled oil droplet structures are viable technologies for drug delivery as well as plausible models for self-replicating materials. When far from equilibrium, droplet systems can become dynamic and effect their own growth and division. Together fusion and division (see figure) demonstrates a droplet replication cycle.

Photophysical and electrochemical properties of a novel metallopolymer containing [Re(bpy)(CO)₃]²⁺ moieties are presented (see figure, ACN=CH₃CN). The electrochemically induce release of the metal centre was proved thought investigation of the mononuclear rhenium complex. This new polymer opens potential applications in the electrochemically induced reaction makes this system highly attractive for delivering a high concentration of luminophore or for imaging.

Stay tuned: New heterobimetallic Sn/Zn single source precursors allowing the controlled preparation of tin-containing ZnO nanocrystals with tunable tin concentrations at low temperatures have been synthesized and characterized. These molecular precursors were suitable for the preparation of highly homogenous tin-containing, ZnO-based TCOs and their application as thin-film FETs lead to very good electrical performance with high electron mobility and on/off ratios.

Attached at the surface: Electroreduction of ferrocene-tailed alkyl iodides at carbon-based cathodes doped with trace amounts of transition metals occurs as a one-electron process providing alkyl radicals. Grafting of these radicals to the graphitized zones of the electrode allows formation of dense alkyl ferrocenyl layers covalently bound to the solid support (see figure; US=ultrasonic).

Biotransformation of odorants and volatiles in humans is essential for understanding their potential roles with regard to physiological action. Eucalyptol, a common odorant, is shown to yield a range of chiral metabolites that are detectable in human urine, thereby revealing information on rarely investigated pathways in human metabolism (see figure).

What a catch! A series of three functionalized metal–organic frameworks have been fabricated by the combination of direct synthesis (template-free) and covalent modification. The resulting frameworks display fairly good thermal stability and moisture resistance. Regardless of the moderate surface area, the grafted carbonyl functionalities enhance the selective CO₂ adsorption capacity (see figure).

In the loop: Combining chemical looping combustion and the calcium looping CO₂ capture scheme allows use of the exothermic reduction reaction of CuO to provide the heat required to calcine CaCO₃. A sol–gel technique has been developed to synthesize new materials containing both CuO and CaO. The addition of Mg²⁺ stabilizes the cyclic CO₂ uptake and minimizes carbon formation (see figure).

Iron catalysis: New iron(II) complexes with polydentate, nitrogen-based ligands were synthesized and applied in the oxidation of benzylic methylene groups and alcohols to the corresponding ketones (see scheme). The impact of the ligand structure and ligand decomposition on the catalytic activity of the iron complexes was investigated.

Enhanced catalytic activity: A Ag/AgBr/Bi₂MoO₆ composite with a hierarchical hollow heterostructure was fabricated (see figure), and was found to exhibit significantly enhanced visible-light photocatalytic activity in the degradation of alizarin red and phenol compared with the Ag/AgBr/Bi₂MoO₆ nanoparticle composite and pure hierarchical Bi₂MoO₆ hollow spheres.