Suprapolymers : The synthesis of symmetrically end‐functionalized polymers in a single step has been developed by means of ring‐opening metathesis polymerization by using a bimetallic ruthenium initiator and functional chain terminators. Self‐assembly of the resulting polymers allows for the formation of supramolecular alternating block copolymers (see figure).
Caught in the middle : The ionomycin calcium complex (see structure; O red, Ca green) was the target of an approach featuring the efficient asymmetric synthesis of an allene by a copper(I)‐mediated anti‐selective SN2′ reaction, a highly stereoselective gold(III)‐catalyzed cycloisomerization of an α‐hydroxyallene, and a Rh‐catalyzed rearrangement of an α‐diazo‐β‐hydroxyketone.
For controlled release and targeted delivery of curcumin in an aqueous medium a method of encapsulating curcumin and magnetic nanoparticles inside porous silica matrix has been developed. Curcumin and superparamagnetic nanoparticles are loaded inside porous silica in a single process. The graphic shows the TEM image of microtomed sample of Fe3O4 particles surrounded by a silica matrix.
First insights into the reaction between a Baylis–Hillman adduct and an allene moiety have been obtained from the novel domino heterocyclization/cross‐coupling reaction of α‐allenols and Baylis–Hillman acetates, which furnishes [(2,5‐dihydrofuran‐3‐yl)methyl]acrylate derivatives in moderate to good yields.
Dipolar aggregation : Examples of a novel class of tweezer molecules have been constructed through the tethering of two dipolar merocyanine chromophores. The electrostatic‐interaction‐directed self‐assembly of these tweezers affords centrosymmetric bimolecular complexes with a unique aggregate geometry of four π‐stacked chromophores (see picture) with an alternating arrangement of their dipole moments and very high dimerization constants, even in the good solvating solvent chloroform.
Breaking point: Switchable peptide surfactants are used to demonstrate that the extent of cross‐linking in an interfacial surfactant layer can control the rate of emulsion coalescence. Pictured is the rupture of an aqueous thin film where the peptide layer lacks sufficient strength to prevent hole formation, but nonetheless dramatically slows the rate of hole expansion.
Fundamental properties: The molar absorption coefficients of CdSe quantum rods are determined experimentally as a function of their dimensions (see figure). Far above the band gap a simple dependence on volume is seen. The behavior at the band gap manifests a concentration of oscillator strength with decreased diameter in agreement with strong quantum confinement behavior.
To each his own : An addressable electrochemical device consisting of orthogonally arranged rows and columns of electrodes has been constructed to monitor protein expression in genetically engineered cells at the single‐cell level. The response based on redox cycling reflected the different expression levels of the enzyme from individual HeLa cells transfected with a plasmid vector including secreted alkaline phosphatase.
En route to molecular electronics : As extended, conjugated oligomers are desirable for molecular electronics, their electrical conductance should display a low attenuation factor. Zinc‐complexed oligo(ethynyleneporphyrindiylethynylene)s have been prepared that are distinguished by ultralow attenuation factors in single‐molecule conductance.
Chemical scrabble : Mechanistic studies of complex organocatalytic cascade reactions are challenging owing to the presence of many species involved. Electrospray ionization mass spectrometry provides details about a one‐pot quadruple organocatalytic cascade reaction, and allows detailed characterization of the reaction and its key intermediates.
The missing link : Ferrocene and porphyrin monolayers are tethered on silicon surfaces with short (see picture, left) or long (right) linkers. Electron transfer to the silicon substrate is faster for monolayers with a short linker.
