Discovering privileged topologies of molecular knots with self-assembling models

Despite the several available strategies to build complex supramolecular constructs, only a handful of different molecular knots have been synthesised so far. Here, in response to the quest for further designable topologies, we use Monte Carlo sampling and molecular dynamics simulations, informed by general principles of supramolecular assembly, as a discovery tool for thermodynamically and kinetically accessible knot types made of helical templates. By combining this approach with the exhaustive enumeration of molecular braiding patterns applicable to more general template geometries, we find that only few selected shapes have the closed, symmetric and quasi-planar character typical of synthetic knots. The corresponding collection of admissible topologies is extremely restricted. It covers all known molecular knots but it especially includes a limited set of novel complex ones that have not yet been obtained experimentally, such as 10124 and 15n41185, making them privileged targets for future self-assembling experiments

Mechanical Bonds and Topological Effects in Radical Dimer Stabilization

While mechanical bonding stabilizes tetrathiafulvalene (TTF) radical dimers, the question arises: what role does topology play in catenanes containing TTF units? Here, we report how topology, together with mechanical bonding, in isomeric [3]- and doubly interlocked [2]catenanes controls the formation of TTF radical dimers within their structural frameworks, including a ring-in-ring complex (formed between an organoplatinum square and a {2+2} macrocyclic polyether containing two 1,5-dioxynaphthalene (DNP) and two TTF units) that is topologically isomeric with the doubly interlocked [2]catenane. The separate TTF units in the two {1+1} macrocycles (each containing also one DNP unit) of the isomeric [3]catenane exhibit slightly different redox properties compared with those in the {2+2} macrocycle present in the [2]catenane, while comparison with its topological isomer reveals substantially different redox behavior. Although the stabilities of the mixed-valence (TTF2)^(•+) dimers are similar in the two catenanes, the radical cationic (TTF^(•+))_2 dimer in the [2]catenane occurs only fleetingly compared with its prominent existence in the [3]catenane, while both dimers are absent altogether in the ring-in-ring complex. The electrochemical behavior of these three radically configurable isomers demonstrates that a fundamental relationship exists between topology and redox properties

Sensory marketing for the organic market : key insights from the EU funded project ECROPOLIS

none13The organic food sector in Europe is growing since several years. However the development of the organic food market varies across European countries. High developed markets (e.g. Germany and Switzerland) coexist with markets in the introduction stage (e.g. Poland). Sensory marketing strategies are not well implemented in the organic sector although this market segment is built on consumers with clear preferences for differentiated sensory properties. Sensory attributes are an important element of organic marketing and a possible tool to create a unique value proposition. The EC funded project Ecropolis investigated the organic market in six European countries (Germany, Poland, The Netherlands, Italy, France and Switzerland). Based on its results the OSIS database was developed and made available on the website. The main results of Ecropolis are summarized for different target groups on different levels: On level 1 a short summary addressed to consumers, retailers and SMEs in English, German, Italian, French, Dutch and Polish is available for different product groups. A concise overview about specific sensory characteristics for the chosen product groups in the six countries is provided, together with information about consumer habits and sensory marketing for those product groups. OSIS offers a sensory journey through the participating countries to learn about country specific preferences. On level 2 more specific guidance for the practical implementation of sensory marketing and sensory analyses in the companies is worked out in form of fact sheets addressed to retailers, SME and SME associations also available in 6 languages. On level 3 all public research reports are available for the interested audience. OSIS is a unique tool that provides support with ready to use information for various questions that occur in organic food production, marketing and communication. Next to OSIS all the Ecropolis project results and dissemination activities are available on the website www.ecropolis.org.mixedM.-L. Cezanne; L. Baumgart; A. Bongartz; K. Buchecker; M. Canavari; T. Gallina Toschi; A. Kole; E. Kostyra; S. Kremer; P. Reichl; A. Spiller; S. Zakowska-Biemans; U. Kretzschmar-Rüger et al.M.-L. Cezanne; L. Baumgart; A. Bongartz; K. Buchecker; M. Canavari; T. Gallina Toschi; A. Kole; E. Kostyra; S. Kremer; P. Reichl; A. Spiller; S. Zakowska-Biemans; U. Kretzschmar-Rüger et al

Multifunctional light beam control device by stimuli-responsive liquid crystal micro-grating structures

There is an increasing need to control light phase with tailored precision via simple means in both fundamental science and industry. One of the best candidates to achieve this goal are electro-optical materials. In this work, a novel technique to modulate the spatial phase profile of a propagating light beam by means of liquid crystals (LC), electro-optically addressed by indium-tin oxide (ITO) grating microstructures, is proposed and experimentally demonstrated. A planar LC cell is assembled between two perpendicularly placed ITO gratings based on microstructured electrodes. By properly selecting only four voltage sources, we modulate the LC-induced phase profile such that non-diffractive Bessel beams, laser stretching, beam steering, and 2D tunable diffraction gratings are generated. In such a way, the proposed LC-tunable component performs as an all-in-one device with unprecedented characteristics and multiple functionalities. The operation voltages are very low and the aperture is large. Moreover, the device operates with a very simple voltage control scheme and it is lightweight and compact. Apart from the demonstrated functionalities, the proposed technique could open further venues of research in optical phase spatial modulation formats based on electro-optical materials.This work was supported by the Comunidad de Madrid and FEDER Program (S2018/NMT-4326), the Ministerio de Economía y Competitividad of Spain (TEC2016-77242-C3-1-R and TEC2016-76021-C2-2-R), the FEDER/Ministerio de Ciencia, Innovación y Universidades and Agencia Estatal de Investigación (RTC2017-6321-1, PID2019-109072RB-C31 and PID2019-107270RB-C21). The authors also acknowledge the support by the Ministry of National Defense of Poland (GBMON/13-995/2018/WAT), Military University of Technology (Grant no. 23-895)

Cryptocapsinepoxide-type Carotenoids from Red Mamey, Pouteria sapota

Three new carotenoids, cryptocapsin-5,6-epoxide, 3ʹ-deoxycapsanthin-5,6-epoxide, and cryptocapsin-5,8-epoxides, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Cryptocapsin-5,6-epoxide was prepared by partial synthesis via epoxidation of cryptocapsin and the (5R,6S)- and (5S,6R)-stereoisomers were identified by HPLC-ECD analysis. Spectroscopic data of the natural (anti) and semisynthetic (syn) derivatives obtained by acid-catalyzed rearrangement of cryptocapsin-5,8-epoxide stereoisomers were compared for structural elucidation. Chiral HPLC separation of natural and semisynthetic samples of cryptocapsin-5,8-epoxides was performed and HPLC-ECD analysis allowed configurational assignment of the separated stereoisomers

Modulation of porosity in a solid material enabled by bulk photoisomerization of an overcrowded alkene

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