Green means go : A polyelectrolyte diode on a microchip exhibits well‐defined nonlinear rectifying behavior. This system visualizes the dynamic distribution of ions in a charged polymer phase under an electric field on a real‐time basis using fluorescence images (see picture). Multiple polyelectrolyte diodes are integrated on a microchip to produce a variety of logic gates based on ionic circuits.
Selecting the ring : tert‐Butyldimethylsilyltriflate (TBSOTf)/NEt3 treatment of alkynyl esters tethered to bicycloalkanones leads to the formation of tricyclic allenoates with total diasteroselectivity at the ring junction. An intramolecular alkynylogous Mukaiyama aldol reaction promoted by a TBSOTf/NEt3 dual activation is involved. This novel methodology was illustrated by a formal total synthesis of (±)‐hamigeran B.
Constructing α‐stereogenic amides and ketones : The highly regioselective and enantioselective conjugate addition of 1,3‐dicarbonyl compounds to 1,4‐dicarbonyl but‐2‐enes has been developed with the chiral bicyclic guanidine as catalyst (ee values up to 97 %; see scheme).
Copper clusters : Two high‐nuclearity copper cages, tricorne Cu21 and saddlelike cyclic Cu16 (see pictures), were synthesized. Magnetic studies and Monte Carlo calculations were also performed to show the overall antiferromagnetic properties of the two compounds.
Spinning wheels : The presented highly resolved multifrequency continuous wave EPR spectra (e.g., see figure) of the heterooctametalic “wheels” Cr7M provide rare examples of high nuclearity polymetallic systems where detailed information on the spin‐Hamiltonian parameters of the ground and excited spin states is observed.
The fiveway junction : The synthesis of ligands with five symmetrically diverging binding sites is described and their assembly into large spherical structures (such as that shown here) investigated.
Up and down: Differential sensing of serine and tyrosine is achieved with aligned CdS nanowire arrays by exploring the pH‐dependent PL behavior of the nanowire arrays toward exposure to the two amino acid solutions (see picture).
Gold caps on silicon nanowires are selectively coated with silver by autometallography (electroless deposition). Changing the conditions of silver deposition, a variety of different coating morphologies can be produced (see figure). The different silver coating morphologies are investigated in terms of their capabilities for surface enhanced Raman scattering (SERS) experiments.
Catalyze this! Detailed study of the mechanism of asymmetric cyanohydrin synthesis catalyzed by VO(salen)X complexes (see figure) led to the development of VO(salen)NCS, as the most active vanadium‐based catalyst yet developed for this reaction.
Deep‐water scrolls: It is demonstrated that amphiphilic rods containing lateral flexible chains self‐assemble into two‐dimensional sheets in aqueous solution (see picture). Remarkably, the sheets roll up reversibly into tubular scrolls upon heating, as confirmed by cryo‐transmission electron microscopy and fluorescence microscopy.
Longer switching wavelengths and good photochemical yields and stabilities of the cis isomers in reducing aqueous environments are achieved by introducing 2,2′‐aminoalkyl substituents into 4,4′‐diamido‐substituted azobenzenes. The products are thus suitable for photocontrol of biomolecular structures in intracellular environments, such as switching between two peptide configurations (see picture).
Calorimetry and signal processing : Vibrational spectroscopies, heat‐flow microcalorimetry, and multivariate analysis are combined to decouple the reaction enthalpies of parallel reactions (see picture). This methodology allows the evaluation of reaction enthalpy from complex systems without recourse to conventional kinetic modeling.
'Onium rings : Incorporation of the trivalent oxygen atom as a structural element within the tricyclic core of 1 – 3 imparts unprecedented stability to this “extraordinary” class of tertiary oxonium ions. Cation 1 is the least reactive and can be refluxed in water for 72 hours with no noticeable decomposition.
Let it shine! The impact of the anchoring group on photovoltaic performance by a series of phthalocyanine sensitisers (see figure) has been demonstrated.
