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Au−Pd Selectivity-switchable Alcohol-oxidation Catalyst: Controlling the Duality of the Mechanism using a Multivariate Approach

Articles from Wiley - 12 giugno, 2019 - 00:00

All about the nano: We have proposed a catalyst comprised of an Au−Pd nanoalloy supported on SrCO3 that can modify the benzyl alcohol selectivity by just changing the pressure of the system. At 5 bar, the chemoselectivity was demonstrated to be for the benzyl benzoate, and at 1 bar, high yields of benzaldehyde were obtained. We were able to prepare a catalyst that is a real selectivity-switchable material.

[Full Papers]
Itaciara E. M. da S. Melo, Dr. Samuel A. A. de Sousa, Laíse N. dos S. Pereira, Jefferson M. Oliveira, Karla P. R. Castro, Dr. Jean C. S. Costa, Dr. Edmilson M. de Moura, Dr. Carla V. R. de Moura, Dr. Marco A. S. Garcia
doi.org/10.1002/cctc.201900512

A Manganese N-Heterocyclic Carbene Catalyst for Reduction of Sulfoxides with Silanes

Articles from Wiley - 12 giugno, 2019 - 00:00

Cheap and safe: An air-stable manganese NHC complex displayed excellent catalytic activity in the reduction of a variety of sulfoxides to sulfides using cheap and safe tetramethyldisiloxane as reducing agent.

[Full Papers]
Dr. Sara C. A. Sousa, Dr. Carlos J. Carrasco, Mara F. Pinto, Dr. Beatriz Royo
doi.org/10.1002/cctc.201900662

Gold-Silver Catalysts: Ruling Factors for Establishing Synergism

Articles from Wiley - 12 giugno, 2019 - 00:00

Silver and Gold! Au−Ag catalysts by DPU and SOL immobilisation have been studied as fresh, calcined in air or reduced in H2, for glycerol oxidation. TEM-EDS, XPS, UV-Vis and CO-DRIFT provided particle size and composition, exposure and oxidation state of metals. Morphological features were correlated to the catalytic behaviour, concluding that Au-rich catalysts show a positive synergistic effect enhancing the catalytic behaviour toward the glycerol oxidation. DPU and SOL techniques creates different structure.

[Full Papers]
Dr. Marta Stucchi, Andrea Jouve, Dr. Alberto Villa, Gergely Nagy, Miklòs Németh, Dr. Claudio Evangelisti, Prof. Rodolfo Zanella, Prof. Laura Prati
doi.org/10.1002/cctc.201900591

Unprecedented Bifunctional Chemistry of Bis(acyl)phosphane Oxides in Aqueous and Alcoholic Media

Articles from Wiley - 12 giugno, 2019 - 00:00

Tailor-made photoinitiators play an important role for efficient radical polymerizations in aqueous media, especially in hydrogel manufacturing. Bis(acyl)phosphane oxides (BAPOs) are among the most active initiators. Herein, we show that they display a remarkable photochemistry in aqueous and alcoholic media (see figure)

[Communications]
Max Schmallegger, Anna Eibel, Jan P. Menzel, Anne-Marie Kelterer, Michal Zalibera, Christopher Barner-Kowollik, Hansjörg Grützmacher, Georg Gescheidt
doi.org/10.1002/chem.201900935

Near-Infrared Circularly Polarized Luminescence through Intramolecular Excimer Formation of Oligo(<i>p</i>-phenyleneethynylene)-Based Double Helicates

Articles from Wiley - 12 giugno, 2019 - 00:00

a “flexible” carbon-based double helicate, that dynamically forms an intramolecular excimer under photoirradiation, has been developed. Furthermore, the intramolecular excimer emits strong near-infrared circularly polarized luminescence. This report offers the new approach to prepare near-infrared CPL emitters.” Read more about the story behind the cover in the Cover Profile and about the research itself on page ▪▪ ff. (DOI: 10.1002/chem.201901467).

[Cover Profile]
Prof. Dr. Koji Miki, Takeru Noda, Prof. Dr. Masayuki Gon, Prof. Dr. Kazuo Tanaka, Prof. Dr. Yoshiki Chujo, Prof. Dr. Yoshiyuki Mizuhata, Prof. Dr. Norihiro Tokitoh, Prof. Dr. Kouichi Ohe
doi.org/10.1002/chem.201902253

Luciferin Regeneration in Firefly Bioluminescence via Proton-Transfer-Facilitated Hydrolysis, Condensation and Chiral Inversion

Articles from Wiley - 12 giugno, 2019 - 00:00

Luciferin Regeneration: A smart biological cycle is established by the conjunction of luciferin regeneration and the bioluminescence process. The detailed process and mechanism of luciferin regeneration in firefly bioluminescence are investigated. Proton transfer processes are suggested to be the key to facilitating the intermolecular and intramolecular nucleophilic attacks in the hydrolysis and condensation steps.

[Articles]
Yuan-Yuan Cheng, Dr. Ya-Jun Liu
doi.org/10.1002/cphc.201900306

Influence of Perfluorohexane-Enriched Atmosphere on Viscoelasticity and Structural Order of Self-Assembled Semifluorinated Alkanes at the Air-Water Interface

Articles from Wiley - 12 giugno, 2019 - 00:00

Atmospheric change: The influence of the atmosphere enriched with perfluorohexane (PFH) on the viscoelasticity and structural order of self-assembled nanodomains of semi-fluorinated diblocks was investigated by the combination of interfacial dilational rheology and grazing-incidence small-angle X-ray scattering. The presence of PFH resulted in an increase in the lateral compressibility and a decrease in the elastic modulus without altering the size and shape of domains.

[Articles]
Salomé Mielke, Dr. Wasim Abuillan, Dr. Mariam Veschgini, Dr. Xianhe Liu, Dr. Oleg Konovalov, Prof. Dr. Marie Pierre Krafft, Prof. Dr. Motomu Tanaka
doi.org/10.1002/cphc.201900316

Surface Confined Synthesis of Hydroxy Functionalized Two-Dimensional Polymer: The Effect of the Position of Hydroxy Groups

Articles from Wiley - 12 giugno, 2019 - 00:00

Small change! Covalently linked nanostructures from oligomers to well-ordered 2DPs or discrete macrocycles were synthesized through surface confined Schiff base reaction. A small change in the monomer structure-exchange of the position of hydroxyl and aldehyde group-induces striking changes in the reaction outcome: from extended 2DPs to discrete macrocycles or catenular structures.

[Articles]
Lili Cao, Dr. Yanxia Yu, Prof. Dr. Xin Zhou, Prof. Dr. Shengbin Lei
doi.org/10.1002/cphc.201900360

5 nm Ordered Structures Self-Assembled by C<sub>2</sub>-Symmetric Hybrids with Polyhedral Oligomeric Silsesquioxane and Hexa-<i>peri</i>-Hexabenzocoronene.

Articles from Wiley - 12 giugno, 2019 - 00:00

Nanotemplates: Dumbbell-shaped, C2-symmetric hybrids consisting of polyhedral oligomeric silsesquioxane and hexa-peri-hexabenzocoronene were designed and synthesized. The 5 nm lamellar structure of p-HBC-2POSS can be transferred from bulk to thin film with a parallel orientation. For p-HBC-4POSS, the increased steric effect is found to stabilize the square columnar phase.

[Articles]
Wei Zhang, Hongbing Pan, Xiaolin Lyu, Dr. Kehua Gu, Anqi Xiao, Prof. Zhihao Shen, Prof. Xing-he Fan
doi.org/10.1002/cphc.201900196

CO<sub>2</sub> Reduction by Hydrogen Pre-Reduced Acceptor-Doped Ceria

Articles from Wiley - 12 giugno, 2019 - 00:00

Reducing CO2: We show that pre-reduced acceptor-doped ceria is capable of CO2 adsorption and reduction to CO. Dissolved hydrogen shows only limited reactivity for the reduction of CO2, but both oxygen vacancies and stored hydrogen participate in the CO2 reduction. CO2 adsorption on ceria leads to various carbonate species with different reactivity, whereby highly stable polydentate carbonates were observed at temperatures as high as 1000 °C.

[Articles]
Matthias Grünbacher, Prof. Dr. Bernhard Klötzer, Dr. Simon Penner
doi.org/10.1002/cphc.201900314

Dependence of the Properties of 2D Nanocomposites Generated by Covalent Crosslinking of Nanosheets on the Interlayer Separation: A Combined Experimental and Theoretical Study

Articles from Wiley - 12 giugno, 2019 - 00:00

Separation matters! Covalently cross-linked 2D-materials are a new class of materials with unique properties. Changing their interlayer separation affects the hydrogen evolution reaction activity of these materials, mainly through altering the magnitude of charge transfer between layers.

[Articles]
Reetendra Singh, Dr. Uttam Gupta, Dr. V. Sampath Kumar, Mohd Monis Ayyub, Prof. Umesh V. Waghmare, Prof. C. N. R. Rao
doi.org/10.1002/cphc.201900292

Monitoring Conformational Changes in an Enzyme Conversion Inhibitor Using Pure Shift Exchange NMR Spectroscopy

Articles from Wiley - 12 giugno, 2019 - 00:00

Simplify 2D EXSY: We show that pure shift methods can be implemented to simplify crowded 2D EXSY spectra, hereby paving the way to an ultra-high-resolution analysis of chemical exchange for processes in the slow regime timescale. The robustness of this approach is demonstrated using the PSYCHE method on a pharmaceutical compound undergoing slow conformational exchange. The resolution enhancement achieved on a broad range of temperatures (40 K) allows for determining exchange rates and activation energies of this interconversion process on several proton sites.

[Articles]
G. Aloui, S. Bouabdallah, J. P. Baltaze, J. E. H. Pucheta, S. Touil, J. Farjon, N. Giraud
doi.org/10.1002/cphc.201900244

Diphenylene-Tetracyanoquinodimethane Cocrystals as Stable Organic Rectifiers

Articles from Wiley - 12 giugno, 2019 - 00:00

The right direction: (E)-1,2-diphenylethene (STB) and 7,7′,8,8′-tetracyanoquinodimethane (TCNQ) act as donor and acceptor respectively in 1 : 1 STB/TCNQ mixed-stacked cocrystals formed by solution volatilization. The strong charge-transfer interaction between the donor and acceptor is the main driving force for the self-assembly process. The cocrystals show rectifying behaviour with a rectification ratio of 26.

[Communications]
Rui Li, Jinfeng Li, Yajing Sun, Dr. Xiaotao Zhang, Prof. Wenping Hu
doi.org/10.1002/cplu.201900197

Donor-/Acceptor-Substituted Tetrakis(arylethynyl)benzenes: The Influence of Donor Group on Optoelectronic Properties

Articles from Wiley - 12 giugno, 2019 - 00:00

Subtle but important: Nine tetrakis(arylethynyl)benzene chromophores possessing 4-butoxyphenyl and pyridyl units as the respective donor and acceptor groups have been synthesized, and their steady-state spectroscopic parameters investigated to learn the effects of small structural variations on the electronic absorption and emission spectra.

[Full Papers]
Wataru Nojo, Prof. I. David Reingold, Jeremy P. Bard, Dr. Daniel T. Chase, Dr. Chun-Lin Deng, Prof. Michael M. Haley
doi.org/10.1002/cplu.201900266

Poly(sodium 4-styrenesulfonate) Assisted Room-Temperature Synthesis for the Mass Production of Bismuth Oxychloride Ultrathin Nanoplates with Enhanced Photocatalytic Activity

Articles from Wiley - 12 giugno, 2019 - 00:00

Thin but strong: 3-5 nm ultrathin BiOCl nanoplates (BiOCl-UTNs) were prepared in large-scale at room-temperature in the solution of ethylene glycol and water with the assistance of poly(sodium 4-styrenesulfonate) (PSS). The strong electrostatic interaction between PSS and [Bi2O2]2+ layers inhibited the typical growth rate of BiOCl nanoplates along <001> direction resulted in the BiOCl-UTNs with high photocatalytic activity.

[Full Papers]
Malik Zeeshan Shahid, Yunwei Wei, Junnuan Wang, Prof. Dr. Guozhu Chen, Dr. Daowei Gao, Dr. Chen Ye, Prof. Dr. Yiqiang Sun, Prof. Dr. Guang-Ning Liu, Prof. Dr. Cuncheng Li
doi.org/10.1002/cplu.201900211

Preparation of Naphthalene Dianhydride Bithiophene Copolymers by Direct Arylation Polycondensation and the Latent Pigment Approach

Articles from Wiley - 12 giugno, 2019 - 00:00

Hidden talents: The combination of direct arylation polymerization and the latent pigment approach enables the synthesis of an n-type naphthalene dianhydride bithiophene copolymer: PNDAT2. The material can be prepared in situ by thermal treatment of the soluble corresponding tetraester precursor PNTET2. The electrochemical LUMO of PNDAT2 is −3.9 eV, consistent with similar naphthalenedimide-containing polymers.

[Full Papers]
Dr. Alessandro Sanzone, Dr. Simone Cimò, Dr. Sara Mattiello, Prof. Riccardo Ruffo, Dr. Irene Facchinetti, Dr. Giorgio E. Bonacchini, Dr. Mario Caironi, Dr. Mauro Sassi, Prof. Dr. Michael Sommer, Prof. Dr. Luca Beverina
doi.org/10.1002/cplu.201900210

Multivalency in Heteroternary Complexes on Cucurbit[8]uril-Functionalized Surfaces: Self-assembly, Patterning, and Exchange Processes

Articles from Wiley - 12 giugno, 2019 - 00:00

Micro/nano-patterning of surfaces using supramolecular chemistry provides additional ways to control pattern formation and selectivity. Dye molecules equipped with different numbers of linker groups can anchor to cucurbituril (CB[8])-functionalized surfaces by formation of ternary host−guest complexes (see figure). The surface patterning of metal and polymer substrates allows the formation of cross-patterns determined by the valency of the dye molecules.

[Full Papers]
Dr. Virginia Valderrey, Dr. Maike Wiemann, Prof. Pascal Jonkheijm, Prof. Stefan Hecht, Prof. Jurriaan Huskens
doi.org/10.1002/cplu.201900181

Hydroxyl Radical Addition to Thymine and Cytosine and Photochemistry of the Adducts at the C6 Position

Articles from Wiley - 12 giugno, 2019 - 00:00

That's radical! Hydroxyl radical (.OH) thermal additions to the C5 and C6 positions of DNA nucleobases cytosine and thymine are investigated. In addition, the different photoinduced processes initiated by visible light taking place in the formed adducts have been determined using multiconfigurational methods.

[Articles]
Vicent J. Borràs, Dr. Antonio Francés-Monerris, Dr. Daniel Roca-Sanjuán
doi.org/10.1002/cptc.201900087

All-Optical Temperature Sensing in Organogel Matrices via Annihilation Upconversion

Articles from Wiley - 12 giugno, 2019 - 00:00

Modified organogels, based on natural oils/waxes and incorporating well-solvated organic dyes sensitive to minor microenvironmental changes, are employed as minimally invasive and ratiometric all-optical temperature sensors. A temperature sensitivity of better than 100 mK centered at 36 °C is obtained by using triplet-triplet annihilation upconversion as a sensing tool. The sensing materials operate in ambient environments, with their excitation and emission spectra fitting advantageously with the tissue transparency window.

[Articles]
Nadzeya Nazarova, Dr. Yuri Avlasevich, Prof. Katharina Landfester, Dr. Stanislav Baluschev
doi.org/10.1002/cptc.201900093

Potential-Energy Surface and Dynamics Simulation of THBDBA: An Annulated Tetraphenylethene Derivative Combining Aggregation-Induced Emission and Switch Behavior

Articles from Wiley - 12 giugno, 2019 - 00:00

Restricted access: An energetically available S1/S0 conical intersection seam allows for non-radiative decay of the aggregation-induced emission active molecule THBDBA to an S0 state in solution (THBDBA=10,10′,11,11′-tetrahydro-5,5′-bidibenzo[a,d][7]annulenylidene). The motion leading from the Franck-Condon structure to the seam is a cyclization, which must be blocked in the aggregate phase.

[Articles]
Dr. Wei-Lu Ding, Dr. Xing-Liang Peng, Prof. Gang-Long Cui, Prof. Ze-Sheng Li, Prof. Lluís Blancafort, Prof. Quan-Song Li
doi.org/10.1002/cptc.201900112

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