ChemPlusChem

The cover picture shows a new colorimetric thin film assembly for studying bacterial biofilms as described by R. Jelinek and co-workers in their Full Paper on page 752 ff. The white background corresponds to a transparent sol-gel layer constructed through a dip-coating technique. Within the sol-gel are domains of polydiacetylene—a unique chromatic polymer which undergoes dramatic color (and fluorescence) transformations. Initially, the polydiacetylene domains appear blue (and nonfluorescent), however, after specific accumulation of bacterial biofilms, the polydiacetylene regions turn intense red (and fluorescent). The polydiacetylene/sol-gel film assembly constitutes a powerful platform for monitoring biofilm formation in situ.

MOF for effective stabilizer for “Pd” and selective host for CO₂: A porous, layered MOF system {[Zn(Himdc)(bipy)].DMF} (1; Himdc=4,5-imidazoledicarboxylate, bipy=4,4'-bipyridine) shows selective gas-storage properties, while the polar nanochannels serve as functional scaffold for the stabilization of highly dispersed Pd nanoparticles. The Pd@MOF1 a hybrid is a highly active and recyclable catalyst for the synthesis of propargylamine derivatives through A³ coupling reactions.

Good egg: A unique yolk–shell Fe₃O₄@C composite with high loading ratio of 90 wt % has been prepared (see figure). As an anode material for lithium-ion batteries, this composite exhibits a high capacity of 680 mAh g⁻¹ even at a large current density of 5 A g⁻¹, and makes it a promising anode material for next-generation lithium-ion batteries.

The red and the blue: Chromatic sol-gel/polydiacetylene (PDA) thin films, assembled through a dip-coating technique, enable in situ colorimetric and fluorescent detection of bacterial biofilm formation (see figure). Interestingly, the gel-embedded PDA domains promote biofilm accumulation. The sol-gel/PDA assembly can be also employed for high-throughput screening of biofilm inhibitors.

High relaxivity contrast agents for targeted MRI: Two biotinylated contrast agents (CAs), [Gd.L^1–2], have been synthesized and characterized for magnetic resonance imaging (see figure). On binding to avidin, the transverse proton relaxivity (r_2p) of [Gd.L¹] undergoes a 906 % increase compared with 225 % for [Gd.L²]. The longitudinal proton relaxivity (r_1p) shows strong field dependence. [Gd.L¹]–avidin allows access of two H₂O molecules to Gd whereas [Gd.L²]–avidin allows one.

The kinetics of the title cycloaddition has been evaluated through differential scanning calorimetry (DSC; see scheme, Bn=benzyl).The application of known kinetic models and mathematical multiple non-linear regressions allow the determination and comparison of E_a, lnA, reaction orders, and reaction enthalpy values. Finally a rate equation for each temperature studied can be established for this particular thermal cycloaddition.

Color films: A new spectroscopic tunability in poly(3,4-ethylenedioxythiophene) (PEDOT) with switching between brown and bright blue hues represents a new design paradigm for the creation of electrodes for use in organic electronic, photovoltaic, and electrochromic devices.

Asymmetric performance boost: A new asymmetric supercapacitor made of poly(N-methylpyrrole)/Au and poly(m-aminobenzene sulfonic acid)-fuctionalized multiwalled carbon nanotubes delivers an extraordinarily high capacitance of 967 F g⁻¹ (see figure).

O dimer, where art thou? Structures of chiral lithium N,P-amides in coordinating solvents are elucidated by using NMR spectroscopy (see figure). Experimental equilibria between different lithium amide dimers are reproduced by using finely tuned dispersion-corrected density functional theory.

Growth management: The morphology, size, and dispersion of Ni(OH)₂ nanocrystals, which are grown on reduced graphene oxide (RGO) sheets from amorphous precursors, can be controlled by temperature-dependent Ostwald ripening processes (see figure), and are critical to electrochemical capacitor performance.

Short is better: The advantages of using mesoporous supports for drug supply depend on the feasibility of mass transfer through confined spaces, which is clearly improved by short-length mesopores insofar as the undesirable effects associated with blocking phenomena are greatly reduced (see figure).

Catch the sun: Seven new donor–spacer–acceptor metal-free organic dyes containing a fluorene and/or thiophene unit as a conjugated spacer have been prepared and their photovoltaic performance studied (see a selection of structures). Theoretical calculations suggest that the small difference in the efficiency of these sensitizers is attributable partly to the degree of effective charge transfer upon excitation, not totally to the absorption profile of the dye molecules.

Bridging the gap: Using 3,4,9,10-perylene tetracarboxylic acid as a bridge to connect mono(6-ethanediamine-6-deoxy)-β-cyclodextrin to the surface of graphene, the nanohybrid material had been synthesized and used as sensing material for electrochemical detection of persistent organic pollutants (see figure, GC=glassy carbon). The limit of detection is 1.0 nM (S/N=3), and is at least eight times lower than for other electrochemical sensors.