A Constitutionally Dynamic Cage Acts as a Convertible and Adaptable Information Manager in Supramolecular Logic

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A Constitutionally Dynamic Cage Acts as a Convertible and Adaptable Information Manager in Supramolecular Logic

A three-component molecular ensemble consisting of a constitutionally dynamic cage, a rotaxane and a luminophore acts as a signal transducer which assimilates three input signals, i. e., Zn2+, H+, and Cu+, to perform two individual logic operations.


Abstract

A three-component molecular ensemble consisting of the constitutionally dynamic cage 1, rotaxane 2 and luminophore 3 acts as a signal transducer which assimilates three input signals, i. e., Zn2+, H+, and Cu+, to perform individual logic operations (e. g. a 3-input NOR gate with catalytic output, 3-input AND gate with optical output) and operates as an unconventional 3-input demultiplexer.

Photo‐Lipids: Light‐Sensitive Nano‐Switches to Control Membrane Properties

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Photo-Lipids: Light-Sensitive Nano-Switches to Control Membrane Properties

An optical control: The structure and organization of eukaryotic plasma membranes has been widely discussed since the introduction of the fluid mosaic model. Light-sensitive lipids were recently introduced in artificial lipid systems and cells to study lipid-lipid and lipid-protein interactions. Here, we review the application of these probes to investigate membrane properties and lateral organization.


Abstract

Biological membranes are described as a complex mixture of lipids and proteins organized according to thermodynamic principles. This chemical and spatial complexity can lead to specialized functional membrane domains enriched with specific lipids and proteins. The interaction between lipids and proteins restricts their lateral diffusion and range of motion, thus altering their function. One approach to investigating these membrane properties is to use chemically accessible probes. In particular, photo-lipids, which contain a light-sensitive azobenzene moiety that changes its configuration from trans- to cis- upon light irradiation, have recently gained popularity for modifying membrane properties. These azobenzene-derived lipids serve as nanotools for manipulating lipid membranes in vitro and in vivo. Here, we will discuss the use of these compounds in artificial and biological membranes as well as their application in drug delivery. We will focus mainly on changes in the membrane's physical properties as well as lipid membrane domains in phase-separated liquid-ordered/liquid-disordered bilayers driven by light, and how these changes in membrane physical properties alter transmembrane protein function.

Direct Electrooxidative Selenylamination of Alkynes: Access to 3‐Selenylindoles

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Direct Electrooxidative Selenylamination of Alkynes: Access to 3-Selenylindoles


Abstract

A novel metal- and oxidant-free electrooxidative selenylamination of o-aminophenacetylenes with diselenides for achieving 3-selenylindoles has been developed with moderate to excellent yield. The reaction proceeded smoothly with a broad substrate scope and highly functional group tolerance. The synthetic practicality of this innovative approach was demonstrated by its easy scalability. Moreover, mechanistic studies revealed that an in-situ generated selenium cation might be the key intermediate for the electrochemical selenocyclization process.

Biotransformations with Imine Reductases: Design of a Practical Process Avoiding an Extractive Work‐Up by Entrapment of Water and Enzymes in an Immobilized Phase

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A process concept for the asymmetric biocatalytic reduction of heterocyclic imines addressing the efficiency of the reaction as well as downstream-processing steps was studied by utilizing a “heterogenized aqueous phase”, which contains the needed enzymes and cofactor within a superabsorber (polyacrylate) network, for the biotransformation. The immobilized biocatalytic system, which comprises an imine reductase IRED, NADPH and an alcohol dehydrogenase for cofactor-recycling, enables to run the reaction in pure organic medium. Thus, instead of an extractive work-up as typical solution for biotransformations in aqueous medium, which, however, can be tedious due formation of emulsions, this type of IRED-catalyzed process leads to a simplified work-up consisting only of a decantation of the liquid organic reaction medium with the product from the heterogenized aqueous biocatalyst system. Exemplified for the (R)-enantioselective reduction of 1-methyl-3,4-dihydroisoquinoline by the IRED of Streptomyces viridochromogenes as a model reaction, a process was developed leading to 98% conversion, 88% yield and >99% ee at a substrate concentration of 40 mM.

Triplet Formation and Triplet‐Triplet Annihilation Upconversion in Iodine Substituted Non‐Orthogonal BODIPY‐Perylene Dyads

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Triplet Formation and Triplet-Triplet Annihilation Upconversion in Iodine Substituted Non-Orthogonal BODIPY-Perylene Dyads

BODIPY-perylene nonorthogonal dyad forms three kinds of triplet species through SOCT-ISC and SO-ISC mechanism. All three kinds of triplet species participate in energy transfer to annihilator molecules. Two annihilator molecules produce one anti-Stokes shifted photon. The presence of iodine on dyad offers 2.6× faster ISC and 8.4× higher upconversion yield.


Abstract

BODIPY-perylene dyads have emerged as useful metal free sensitizers for triplet-triplet annihilation upconversion (TTAUC), these dyads are capable of efficient triplet generation via spin-orbit charge transfer intersystem crossing (SOCT-ISC). This important route to triplet formation requires dyads in which two moieties are oriented perpendicular to each other. In this contribution, we give a deeper insight on the behavior of recently reported BODIPY-perylene dyads, where BODIPY-perylene dihedral exhibits a non-orthogonal dyad geometry. The intersystem crossing of BODIPY-perylene dyads with and without iodine are investigated using femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) spectroscopy. The concurrent decay of the singlet charge transfer state (1CT) and rise of triplet states in both the iodinated and non-iodinated dyads confirms the SOCT-ISC as the main intersystem crossing pathway despite the altered geometry of the dyads. The presence of an iodine atom on the BODIPY-moiety enables intersystem crossing 2.6-times faster and provides a higher triplet yield with respect to dyad without iodine. The upconversion quantum yield ( ) is 8.4-times higher in the sample containing iodinated dyad as sensitizer and perylene as annihilator. The triplet-triplet energy transfer rate (k TTET) is ~8×108 M−1 s−1 for both iodinated and non-iodinated sensitizer containing TTAUC systems in 1,4-dioxane.

Preparation of 3‐D Porous Pure Al Electrode for Al‐Air Battery Anode and Comparison of its Electrochemical Performance with a Smooth Surface Electrode

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Preparation of 3-D Porous Pure Al Electrode for Al-Air Battery Anode and Comparison of its Electrochemical Performance with a Smooth Surface Electrode

3D-porous and smooth surface anodes for the Al-air battery: Al electrodes were produced with smooth and porous surfaces by salt casting. LSV analysis showed that the current density of the porous electrode was three times higher. EIS analysis gives lower charge transfer resistance for the Al-porous electrode. The power density of the Al-porous electrode was approximately 42 % higher than that of the Al-smooth electrode.


Abstract

This study compared the electrochemical performances of porous surface electrodes obtained by the salt casting process against a smooth surface electrode. Potentiodynamic polarization test, linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) tests of porous and smooth Al electrodes were performed using 0.5 M NaOH solution. According to the Tafel analysis, the Jcor value of the Al-porous electrode was measured as 3.23 mA cm−2, which is approximately 55 % higher than the Al-smooth electrode. The Ecor value was more negative for the Al-porous electrode. Results of the low charge transfer resistance (2.2 Ω) of the Al-porous electrode compared to the Al-smooth electrode (2.8 Ω) concluded that the porous surface was increased the current density by increasing charge transport due to higher surface area. The galvanostatic discharge tests of the electrodes were carried out in an Al-air battery test cell using a graphite carbon air cathode. As a result, the power density of the Al-porous electrode was approximately 42 % higher than the Al-smooth surface electrode.

Solid‐state Chromism of Zwitterionic Triarylmethylium Salts

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Solid-state Chromism of Zwitterionic Triarylmethylium Salts

A zwitterionic triarylmethylium salt exhibits solid-state chromism by dissolution & evaporation or evaporation, which shows green, yellow and red. The same color crystalls were obtained from different recrystallization connditions. Correlation between the chromism and molecular structure were studied by using diffuse reflectance measurement, single crystal x-ray analysis and powder x-ray diffraction.


Abstract

Zwitterionic triarylmethylium dyes 1 and 2 were synthesized by using a synthetic unit of a tetraarylborate. The zwitterionic structure of 1 and 2 exhibits varied molecular assembly and induces charge transfer transition. These properties gave them specific optical features such as solvatochromism and mechanochromism in the solid state, that is, the green solid of 2 changes to yellow or red solid by dissolution & evaporation or grinding, respectively. The three colors were reproduced independently in different crystal forms, which were prepared from different recrystallization conditions. The diffuse reflectance measurement and powder X-ray diffraction demonstrated the correlation between the colors and the solid-state structures. The single crystal X-ray analysis revealed face-to-face dimeric assembly in each crystal. Among the crystal structures, the intermolecular distances and packing patterns were notable differences. Based on these results, it can be suggested that unique color change of zwitterionic triarylmethylium dyes originates from the alternation of intermolecular interactions.

In silico end‐capped engineering of 4,4′‐dimethyl‐[2, 2′‐bithiazole] core‐based acceptor materials for high‐performance organic solar cells

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In silico end-capped engineering of 4,4′-dimethyl-[2, 2′-bithiazole] core-based acceptor materials for high-performance organic solar cells

In the present study, five new acceptor molecules were designed by end group modification of previously synthesized reference molecule to obtain better in silico efficiency of solar cell devices. All newly fabricated molecules (D1-D5) displayed smaller energy gap, reasonable electron reorganizational energy values, and open circuit voltage (V oc). D3 being an acceptor when blended with donor polymer portrayed highest charge transfer capability. D5 molecule exhibits higher V oc, greater light harvesting efficiency, and superior fill factor illustrating superior behavior than other molecules.


Abstract

Organic solar cells (OSCs) have grabbed the attention of researchers due to good power conversion efficiency, low cost, and ability to compensate for light deficit. The aim of the present research work is to increase the efficiency of previously synthesized reference (R) molecule 2,2′-((2Z,2′Z)-(((4,4′-dimethyl-[2,2′-bithiazole]-5,5′-diyl)bis(4-(2-butyloctyl)thiophene-5,2-diyl))bis (methaneylylidene))bis(5,6-dichloro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile by improving its photovoltaic properties via end cap engineering. Five new acceptors, namely, E1, E2, E3, E4, and E5, are used to substitute the end group of reference molecule. Several parameters have been analyzed using density functional theory including the absorption maxima, charge transfer analysis, frontier molecular orbital (FMO), open circuit voltage (V oc), density of states (DOS), photochemical characteristics, transition density matrix (TDM), and the electron-hole reorganization energies to evaluate the efficiency of specially engineered molecules. All the engineered molecules (D1-D5) had smaller energy gap (4.50–4.71 eV) compared with reference (4.75 eV) and absorption maxima in the range of 443.37–482.67 nm in solvent phase due to end-cap acceptor modification. Fabricated molecules (D1-D5) showed smaller electron reorganizational energy values (0.18–0.27 eV) and V oc ranging from 1.94 to 2.40 eV. Designed molecule D3 being an acceptor when blended with donor polymer (PTB7-Th) portrayed highest charge transfer capability owing to its smallest energy gap (4.50 eV) among all the engineered molecules. D5 molecule exhibits higher V oc (2.40 eV), greater LHE (0.9988), and superior result of fill factor (94.15%) as compared with R, which leads to improve the efficiency of OSCs. Theoretical findings illustrated the superior behavior of all the designed molecules making them suitable aspirants to construct efficient OSC devices.