Article
Chemistry, Physical
Pablo D. Nieres, Victoria A. Vaillard, Juan Zelin, Nicolas I. Neuman, Andres F. Trasarti, Carlos R. Apesteguia, Santiago E. Vaillard
Summary: HG(2) is a reliable and extremely useful catalyst for synthesizing olefins, especially for the self-metathesis reaction of unsaturated fatty acid methyl esters. Silica gel is a promising support for large scale application of HG(2) due to its beneficial characteristics. However, storing the supported catalyst under atmospheric conditions at 298K significantly decreases its activity, which compromises its stability and applicability. Detailed experimental and spectroscopic studies, along with electronic structure calculations, shed light on the catalyst decomposition process.
Article
Chemistry, Physical
Charles Killeen, Jie Liu, Harmen S. S. Zijlstra, Florian Maass, James Piers, Reid Adams, Allen Oliver, J. Scott McIndoe
Summary: Ring-closing metathesis (RCM) is a versatile method for forming cyclic structural elements. Real-time analysis using electrospray ionization mass spectrometry (ESI-MS) was applied to study the RCM reaction, revealing the presence of by-products and the decomposition of the catalyst. Isomerization reactions play a significant role in affecting the yield of the desired product, especially in slow RCM reactions.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Minghang Qiao, Yi Xing, Lei Xie, Biao Kong, Freddy Kleitz, Xiaoyu Li, Xin Du
Summary: This paper presents a temperature-controlled swelling approach for facile synthesis of functional yolk@shell structured nanospheres with tunable inner core and mesoporous shell. The method shows great potential for wide applications in biology and medicine.
Article
Chemistry, Physical
Mona O. Albalawi, Laura Falivene, Abdesslem Jedidi, Osman Osman, Shaaban A. Elroby, Luigi Cavallo
Summary: Ruthenium based catalysts are successful in catalyzing metathesis processes for synthesizing new carbon-carbon bonds. The use of density functional theory (DFT) calculations has significantly contributed to the development of new catalysts by providing fundamental understandings. An in-depth computational study on the binding of anion ligands to the metal has provided key insights on the global properties and reactivity of the catalyst.
MOLECULAR CATALYSIS
(2021)
Article
Multidisciplinary Sciences
Thomas G. Pattison, Shuo Wang, Robert D. Miller, Gang-yu Liu, Greg G. Qiao
Summary: Macroscale additive manufacturing has developed significantly, but nanoscale formation of polymeric features from the bottom-up is not yet achieved. This study demonstrates a rapid crosslinking technique using an atomic force microscope, enabling fast curing of crosslinkable polymers in the presence of catalysts.
NATURE COMMUNICATIONS
(2022)
Article
Polymer Science
Henry L. Cater, Iana Balynska, Marshall J. Allen, Benny D. Freeman, Zachariah A. Page
Summary: This paper presents a systematic study on ROMP with endo-norbornene monomers using stable chelated Ru-alkylidene initiators. The study shows that ROMP with endo-norbornene monomers is versatile and robust, providing access to polymers with excellent molecular weight control, low dispersities, good functional group tolerance, and high chain-end fidelity. The process is oxygen-tolerant and can be performed under ambient conditions, allowing for the synthesis of mechanically robust thermoplastics with high glass transition and decomposition temperatures.
Article
Chemistry, Physical
Andre Both, Thomas Roider, Felix Ziegler, Xiulan Xie, Michael R. Buchmeiser, Ulrich Tallarek
Summary: In this study, a 2(nd)-generation Grubbs-Hoveyda type catalyst was immobilized in mesoporous silica and used in the ring-closing metathesis (RCM) of an alpha,omega-diene to a large macro(mono)cycle. The relationship between substrate concentration, reaction time, and overall experiment time on the rate of isomerization under spatial confinement with continuous-flow microreactors was investigated. The results showed that higher substrate concentrations and longer reaction times increased the isomerization rate, while prolonged overall experiment times led to a decline in the isomerization rate.
Article
Chemistry, Inorganic & Nuclear
Anna Marczyk, Nirmalya Mukherjee, Bartosz Trzaskowski
Summary: This study investigates the initiation rates of ruthenium metathesis catalysts by introducing various modifications. The results show that catalysts with electron-withdrawing substituents in the benzylidene part can achieve very fast initiation, with -SO2C4F9 derivatives being the most effective initiators.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2022)
Article
Pharmacology & Pharmacy
Yongsheng Ji, Shuhui Song, Xinyi Li, Ruihong Lv, Le Wu, Haohao Wang, Mingzhuo Cao
Summary: An innovative magnetic drug delivery system with a yolk-shell structure and targeting function was developed in this study, showing excellent biocompatibility and pharmaceutical effects through sustained release and enhanced cellular uptake.
JOURNAL OF DRUG DELIVERY SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Applied
Louis Monsigny, Jakub Piatkowski, Damian Trzybinski, Krzysztof Wozniak, Tomasz Nienaltowski, Anna Kajetanowicz, Karol Grela
Summary: Two new ruthenium complexes, Sil-II and Sil-II', were synthesized and characterized as catalysts for olefin metathesis reactions. Sil-II' showed better stability and productivity compared to Sil-II, and kinetic experiments revealed differences in initiation mechanisms between the two catalysts.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Physical
Anne V. Le, Biplab Rajbanshi, Raul F. Lobo, Peng Bai
Summary: In this study, DFT calculations were used to investigate the mechanisms of propene metathesis catalyzed by WOx/SiO2. The results showed that there are still many mechanisms of heterogeneous catalyzed metathesis reactions that are not well understood. The pseudo-Wittig mechanism was found to be the most favorable method for generating initial alkylidene active sites. The allylic and vinylic C-H activations are more difficult and require the reduction of surface sites to W(+4).
JOURNAL OF CATALYSIS
(2023)
Article
Food Science & Technology
Ersin Karatas, Ahmet Tulek, Deniz Yildirim, Faruk Tamturk, Baris Binay
Summary: This study prepared highly stable biocatalysts by immobilizing exo-polygalacturonase on mesoporous silica, showing great potential in apple juice clarification. The immobilized enzymes exhibited significantly improved stability and efficiency, making them promising candidates for pectin biodegradation.
Article
Chemistry, Organic
Hui-Qi Ni, Zi-Qi Li, Van T. Tran, Keary M. Engle
Summary: A direct and modular method has been reported to access non-conjugated alkenyl amides containing the directing auxiliary 8-aminoquinoline (AQ) and related groups via cross-metathesis. This method allows the synthesis of internal alkene products that are difficult to prepare, which can participate in various directed alkene functionalization reactions.
Article
Chemistry, Multidisciplinary
Jessica Rodriguez, Maxime Boudjelel, Leonard J. Mueller, Richard R. Schrock, Matthew P. Conley
Summary: This passage describes the reaction of W(NAr) ((C4H8)-C-13) (OSiPh3)(2) (1) with partially dehydroxylated silica at 700 degrees C. The results show that the reaction outcome is highly influenced by the reaction conditions. Different compounds are formed as products, and their formation is affected by light and heating treatment.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Inorganic & Nuclear
Pavel A. Kumandin, Alexandra S. Antonova, Roman A. Novikov, Kirill A. Vasilyev, Marina A. Vinokurova, Mikhail S. Grigoriev, Anton P. Novikov, Daria K. Polianskaia, Kirill B. Polyanskii, Fedor I. Zubkov
Summary: This study investigates the synthesis and catalytic activity of ruthenium chelates with various heteroatoms in a six-membered ring. The researchers successfully prepared second-generation Hoveyda-Grubbs-type catalysts with a sulfur-ruthenium coordinate bond using standard procedures. They found that the trans-isomers of these catalysts showed excellent catalytic activity, outperforming the commercially available HG-II catalyst.
