Efficient asymmetric catalysis of chiral organoaluminum complex for enantioselective ene reactions of aldehydes

Chiral organoaluminum complex 1 efficiently catalyzed the asymmetric hetero-ene reaction of commercially available 2-methoxypropene (2) with aldehydes under mild conditions to give the corresponding β-hydroxymethyl ketones 3 in good to excellent chemical yields with high enantiomeric excesses. The asymmetric catalysis of 1 was further applied to the carbonyl addition of methallylsilanes, where exclusive formation of the optically active allylic silanes 5 was achieved.     

Unprecedented Encapsulation of Carbonyl Guest with Designer Lewis Acid Receptor

A reaction chamber is formed by a cage compound in which a dicarbonyl guest molecule is encapsulated by two bowl-shaped aluminum tris(2,6-diphenylphenoxide) molecules through Lewis acid–base interactions (structure of complex with 1,4-dimethylpiperazine-2,5-dione depicted). The carbonyl compound held inside the molecular capsule is effectively protected against the approach of external nucleophiles. On the other hand, the chamber is large enough to allow Diels–Alder cycloadditions to take place under mild conditions and with high selectivity.     

Visualization of interacting crossing vortex lattices in the presence of quenched disorder

We have imaged interacting crossing pancake vortex (PV) and Josephson vortex (JV) lattices in highly anisotropic Bi2Sr2CaCu2O(8+delta) single crystals under tilted magnetic fields. The dependence of vortex structures on in-plane field is in good quantitative agreement with theoretical predictions, yielding an almost temperature-independent anisotropy parameter of gamma=640+/-25. We directly confirm that the PV/JV attraction arises from small PV displacements in the presence of JV supercurrents and demonstrate how the existence of quenched disorder leads to indirect JV pinning and dynamic vortex fragmentation.     

Adaptive H∞ Chaos Anti-synchronization

A new adaptive H∞ anti-synchronization （AHAS） method is proposed for chaotic systems in the presence of unknown parameters and external disturbances. Based on the Lyapunov theory and linear matrix inequality formulation, the AHAS controller with adaptive laws of unknown parameters is derived to not only guarantee adaptive anti-synchronization but also reduce the effect of external disturbances to an H∞ norm constraint. As an application of the proposed AHAS method, the H∞anti-synchronization problem for Genesio-Tesi chaotic systems is investigated.     

Digital Imaging-based Colourimetry for Enzymatic Processes in Transparent Liquid Marbles

Liquid marbles are a promising microreactor platform that recently attracts significant research interest owing to their ability to accommodate a wide range of micro reactions. However, the use of destructive and ex-situ methods to monitor reactions impairs the potential of liquid-marble-based microreactors. This paper proposes a non-destructive, in situ, and cost-effective digital-imaging-based colourimetric monitoring method for transparent liquid marbles, using the enzymatic hydrolysis of starch as an illustrative example. The colourimetric reaction between starch and iodine produces a complex that exhibits a dark blue colour. We found that the absorbance of red channel of digital images showed a linear relationship with starch concentration with high sensitivity and repeatability. This digital-imaging-based colourimetric method was used to study the hydrolysis of starch by α-amylase. The results show high accuracy and applicability of first-order kinetics for this reaction. The demonstration of digital-imaging-based colourimetry indicates the potential of liquid marble-based microreactors.     

Intercalation of cobaltammine complex ions into layered manganese oxide

The intercalation of Co(2+), [Co(NH(3))(6)](3+), and [Co(NH(3))(5)Cl](2+) ions into layered manganese oxide (birnessite) was studied by chemical, XRD, SEM, IR, and DTA-TG analyses. The intercalation reaction progressed by a 2:1 or 3:1 ion-exchange mechanism depending on the valence of the starting ions. The oxidation state of cobalt did not change with the intercalation reaction. The intercalation of [Co(NH(3))(6)](3+) ions resulted in an increase of basal spacing from 0.716 to 0.956 nm, giving a layered structure material consisting mainly of platelike particles. The chemical analysis results showed that the structure of [Co(NH(3))(6)](3+) ions was maintained in the interlayer. On the other hand, an H(2)O/NH(3) ligand exchange reaction progressed for the intercalation of [Co(NH(3))(5)Cl](2+) ions, resulting in an increase in the basal spacing from 0.716 to 0.956 nm.     

Synthesis and characterization of thieno[3,2‐b]thiophene‐isoindigo‐based copolymers as electron donor and hole transport materials for bulk‐heterojunction polymer solar cells

A novel class of thieno[3,2‐b]thiophene (TT) and isoindigo based copolymers were synthesized and evaluated as electron donor and hole transport materials in bulk‐heterojunction polymer solar cells (BHJ PSCs). These π‐conjugated donor‐acceptor polymers were derived from fused TT and isoindigo structures bridged by thiophene units. The band‐gaps and the highest occupied molecular orbital (HOMO) levels of the polymers were tuned using different conjugating lengths of thiophene units on the main chains, providing band‐gaps from 1.55 to 1.91 eV and HOMO levels from ?5.34 to ?5.71 eV, respectively. The corresponding lowest unoccupied molecular orbital (LUMO) levels were appropriately adjusted with the isoindigo units. Conventional BHJ PSCs (ITO/PEDOT:PSS/active layer/interlayer/Al) with an active layer composed of the polymer and PC₇₁BM were fabricated for evaluation. Power conversion efficiency from a low of 1.25% to a high of 4.69% were achieved with the best performing device provided by the D?π?A polymer with a relatively board absorption spectrum, high absorption coefficient, and more uniform blend morphology. These results demonstrate the potential of this class of thieno[3,2‐b]thiophene‐isoindigo‐based polymers as efficient electron donor and hole transport polymers for BHJ PSCs. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013