Formic acid adsorption on ruthenium nanoparticles of different sizes allows differentiation of differently bound formate species by solution 13C NMR spectroscopy (see picture). The chemical shifts are comparable to those of organometallic analogues, thus indicating that formate can act as a probe to distinguish surface features of metallic nanoparticles in solution with good quantification and resolution.
One‐nucleotide differences in microRNAs (miRNAs) can be discriminated in an assay based on a branched rolling‐circle amplification (BRCA) reaction and fluorescence quantification. With the proposed method miRNA can be detected at concentrations as low as 10 fM , and the miRNA in a total RNA sample of a few nanograms can be determined.
Supramolecular chirality and liquid crystalline OFET : Achiral end‐capped oligothiophenes can be tuned to exhibit supramolecular chirality with unique striped textures showing distinct circular dichroism signals as well as a highly ordered SmE phase that leads to high hole carrier mobility.
Donor1+donor2→acceptor : The second‐order NLO molecular properties of a class of dipolar chromophores that incorporate the following design elements are investigated: 1) a substituted hydrazono moiety as a strong donor; 2) a pyrrole ring as an auxiliary donor; 3) strong acceptor groups (see figure). Their first hyperpolarisabilities show good promise for use in electro‐optical devices.
Meeting the challenge : The zinc/amino alcohol catalyzed enantioselective addition of terminal alkynes to aldehydes is effective with both phenylacetylene and methyl propiolate, leading to chiral secondary propargyl alcohols with very high enantioselectivity (see scheme).
Tracking down potential killers : Strong host–guest interactions enable the facile combination of polycationic cyclodextrin binding motifs (blue) with fluorescent reporters (orange) tethered to a hydrophobic guest molecule (dark green). An array of supramolecular fluorescent receptors prepared by this modular approach was used for the pattern‐based recognition of negatively charged contaminants in the anticoagulant drug heparin.
Showing their true colors? Full emission color tuning in the visible region can be achieved with salen–aluminum complexes that are electronically modulated at C5 of the phenoxide ring in the salen moiety. Emission spectra for various substituents R5 are shown (EWG: electron‐withdrawing group, EDG: electron‐donating group).
Phased out: A combination of electrochemical and optical techniques is used to study the interaction of hydrogen with palladium nanoclusters. Hydrogen pressure‐composition isotherms reveal the reduced presence of the β phase in palladium nanoclusters. Hydrogen extraction transients relate the reduced miscibility gap to a core‐shell phase transformation in the palladium nanoclusters (see picture).
Making connections : A hydroxy‐centered trinuclear nickel cluster has been employed to construct a highly connected, highly symmetric framework with a uninodal nine‐connected topology. An array of triakis tetrahedra leads to a biporous intersecting‐channel system (see picture).
Borenes and boranes : Silylaminoiminoborenes, such as depicted, were isolated after treatment of halogen triels with silylaminofluoroboranes. In addition, novel aryl‐ and silyl‐substituted diaminofluoroboranes were also prepared in order to substantiate this reaction route.
Catalytic rivals : Both CO2‐protected tetrahydropyrimidin‐2‐ylidene‐based N‐heterocyclic carbenes (NHCs) and SnII‐1,3‐dimesitylimidazol‐2‐ylidene, as well as SnII‐1,3‐dimesitylimidazolin‐2‐ylidene complexes (example displayed), have been identified as truly latent catalysts for polyurethane (PUR) synthesis rivaling all existing systems both in activity and latency.
