Driven round the twist by DNA : One‐dimensional helical J‐aggregates are formed by the self‐assembly of thymidylic acid appended anthracene dye (shown in red and yellow) in the presence of complementary single‐stranded oligoadenylic acid (shown in green and blue) in an aqueous solution.
A new way to make a bang : Several functionalized 1‐ethyl‐5‐aminotetrazoles, 1‐ethyl‐5‐nitrimino‐tetrazoles, and copper complexes have been synthesized and their chemical and energetic properties have been comprehensively characterized. The compounds belong to all classes of “energetic materials”: explosives, propellants, and pyrotechnics.
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.
Mild reaction conditions are the advantage of the title reaction, which allows straightforward entry to a variety of ynamides starting from readily available 1,1‐dibromo‐1‐alkenes, which act as attractive alkynylating agents (see scheme; EWG=electron‐withdrawing group, DMF=N,N‐dimethylformamide).
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.
Don't get trapped : The effect of conjugating electron‐withdrawing groups and α‐anion‐stabilizing heteroatom substituents on configurational stability of chiral carbanions through a double bond was examined on the basis of extent of chirality transfer in intramolecular trapping in [2,3]‐Wittig rearrangement of chiral 3‐substituted 1‐propenyloxy‐1‐phenyl‐2‐propen‐1‐yl carbanions (see scheme).
A polymeric thermosensor composed of the thermo‐responsive block copolymer Pluronic F127 (PF127) and the near‐infrared (NIR) dye Cy5.5 can simply monitor, image, and analyze temperature changes. The thermoprobe exhibited linear NIR fluorescent emission changes (see figure) over a broad temperature range (0–80 °C).
A convenient route with high stereo control to γ‐acetoxy dienoates is provided by the reaction of methyl propiolate with aldehydes in the presence of ZnEt2 and N‐methylimidazole at room temperature, followed by the catalytic conversion of the resulting γ‐hydroxy‐α,β‐acetylenic esters with p‐N,N‐dimethylaminopyridine (DMAP) in acetic anhydride (see scheme).
Pressing the configurational switch : Use of enantiomeric Ir catalysts allows the vinylpiperidine building blocks 2 a and 2 b to be synthesized with high selectivity. Total syntheses of the dendrobate alkaloid (+)‐241 D, its C6‐epimer, and a spruce alkaloid are presented as applications.
Easily disrupted : Micelles of a new amphiphilic block copolymer that bear coumarin groups are sensitive to near infrared light by two‐photon absorption of the chromophore. Disruption of the micelles under irradiation at 794 nm results in release of both photocleaved coumarin and encapsulated nile red from the hydrophobic core of micelle into aqueous solution, which results in opposing changes in fluorescence emission intensity.
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.
Molecular versatility : Unusual reactivities such as hydrolysis, nucleophilic aromatic substitution, and addition reactions of human orotidine‐5′‐monophosphate decarboxylase are explained by crystal structures and involve a nucleophilic lysine residue that normally is expected to act solely as a general base (RP=phosphoribosyl, R=CO2H, CN, acetyl, N3, I; R′=OH, SH, acetyl, hydroxymethyl).
