Article
Polymer Science
Jian Lin, Peng Wang, Lei Fan, Tian Xiao, Jianhua Cheng, Xia Chen
Summary: Bi- and tetra-lithium quinolyl/pyridyl-amino complexes were synthesized and characterized, showing high catalytic activity in the polymerization of rac-lactice and e-caprolactone. The number of metal centers and ligand structures were found to be crucial factors in determining the reactivity of the catalyst in ring-opening polymerization (ROP).
Article
Chemistry, Inorganic & Nuclear
Xiaowei Xu, Han Lu, Gen Luo, Xiaohui Kang, Yi Luo
Summary: The origin of opposite reactivity in the ring-opening polymerizations of lactide (LA) and cyclohexene oxide (CHO) catalyzed by redox-switchable bis(imino)pyridine iron complexes has been computationally elucidated. Larger geometrical deformation leads to lower activity of the oxidized form (Fe-ox) of the iron catalyst toward LA polymerization compared to the reduced analogue (Fe-red), while the higher activity of Fe-ox toward CHO polymerization is attributed to stronger interaction with CHO moieties due to its higher electrophilicity. This theoretical understanding has led to the computational modeling of various Fe-ox analogues with modified substituents to increase their electrophilicity and lower energy barriers in CHO enchainment.
INORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Multidisciplinary
Phong K. Quach, Jesse H. Hsu, Ivan Keresztes, Brett P. Fors, Tristan H. Lambert
Summary: The ring-opening metathesis polymerization of cyclopropenes using hydrazonium initiators was investigated. The initiators, formed by condensing 2,3-diazabicyclo[2.2.2]octane and an aldehyde, polymerize cyclopropene monomers through a sequence of [3+2] cycloaddition and cycloreversion reactions. The study showed that the monomer to initiator ratio had a positive correlation with the degree of polymerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Jiahao Gao, Wenjuan Zhang, Xing Wang, Rui Wang, Mingyang Han, Furong Cao, Xiang Hao
Summary: A series of potassium amidate complexes were prepared and characterized, and the molecular structures of two complexes were determined by X-ray diffraction. These complexes exhibited high catalytic activity in the ring-opening polymerization of L-lactide and rac-LA, producing linear polylactides with specific end groups. The complexes acted as selective and active catalysts for controlled ring-opening polymerization.
Article
Polymer Science
Zhunxuan Li, Rui Chen, Ying Wang, Linlin Zhu, Wenyi Luo, Zhen Zhang, Nikos Hadjichristidis
Summary: An efficient synthetic methodology was developed for the modification of hyperbranched polyethyleneimines (PEI) using N-sulfonyl aziridines, resulting in materials with unique fluorescence properties and the ability to remove hazardous metals.
Review
Chemistry, Multidisciplinary
Mathieu J. -L. Tschan, Regis M. Gauvin, Christophe M. Thomas
Summary: This review summarizes the recent developments in biodegradable polymeric materials over the past decade, with a focus on the stereoselective ring-opening polymerization of cyclic esters and the emergence of metal-free stereocontrolled ROP technology. The study emphasizes the synthesis of new stereoselective polymerization catalysts and chiral monomers, while also highlighting the quantification and mechanisms of stereocontrol.
CHEMICAL SOCIETY REVIEWS
(2021)
Review
Chemistry, Applied
Nina Guy, Olivia Giani, Sebastien Blanquer, Julien Pinaud, Jean-Jacques Robin
Summary: Photopolymerization is gaining interest in both industrial and academic fields due to its high reaction kinetics, low emissions of organic solvents, and reduced shrinking stress. This method has mainly been developed for radical polymerization of vinyl monomers and to a lesser extent for ring-opening polymerization (ROP). With the emergence of new initiating systems, the photopolymerization of various cyclic monomers has expanded beyond epoxides, which were the first monomers polymerized by cationic ring-opening polymerization (CROP).
PROGRESS IN ORGANIC COATINGS
(2021)
Article
Chemistry, Inorganic & Nuclear
Tian Xing, Timothy J. Prior, Kai Chen, Carl Redshaw
Summary: A variety of complexes based on calixarene structures were synthesized and evaluated for their potential as catalysts in the ring opening polymerization of epsilon-caprolactone, delta-valerolactone, and rac-lactide. The complexes bearing oxacalixarene structures exhibited better activities compared to azacalixarene-based pre-catalysts.
DALTON TRANSACTIONS
(2021)
Article
Polymer Science
Masato Suzuki, Aya Watanabe, Raimu Kawai, Ryo Sato, Shin-ichi Matsuoka, Susumu Kawauchi
Summary: This study reports the ring-opening polymerization of thiolactide, where thiolactic acid undergoes cyclic condensation to form rac-thiolactide, which is then polymerized using a combination of thiol as initiator and DBU as catalyst. The polymerization process was found to be in equilibrium and displayed different structural characteristics and degradability compared to polylactide.
Review
Chemistry, Multidisciplinary
Xiaoqian Wang, Ziyu Huo, Xiaoyu Xie, Narasimhamurthy Shanaiah, Rong Tong
Summary: The demand to replace unsustainable polyolefins drives the transformation of renewable resources into functional and degradable polymers. However, the properties of many degradable homopolymers are inferior to commodity polyolefins, limiting their utility. One-pot synthesis of sequence-defined copolymers from cyclic monomer mixtures is attractive in terms of concept and economics, as it maximizes materials usage and improves polymer performance. Recent advances in one-pot, sequence-controlled polymerizations of cyclic monomer mixtures using a single catalytic system that combines multiple catalytic cycles are highlighted, including the scopes of cyclic monomers, catalysts, and polymerization mechanisms.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Polymer Science
U. L. D. Inush Kalana, Partha P. Datta, Rukshika S. Hewawasam, Elizabeth T. Kiesewetter, Matthew K. Kiesewetter
Summary: This study discusses the H-bond mediated organocatalytic ring-opening polymerizations of four new thionolactone monomers, emphasizing the importance of organocatalysts in synthesizing thionolactone polymers and copolymers, as well as exploring the application of thionoester as a chemical handle in polymer backbone.
Review
Polymer Science
Chengjian Zhang, Xiaowei Geng, Xinghong Zhang, Yves Gnanou, Xiaoshuang Feng
Summary: Sensitivity to environmental concerns and the demand for metal-free polymeric materials have driven research towards breakthroughs in organocatalytic polymerizations. Triethyl borane (TEB) has been discovered as an exceptional Lewis acid, serving to generate ate complexes and activate epoxides. Lewis pairs consisting of alkyl boranes combined with onium salts or organic bases have demonstrated unprecedented versatility for (co)polymerizations of oxygenated monomers, producing various oxygenated polymers. This review summarizes the progress made in TEB-mediated polymerization systems and proposes future challenges in organocatalytic synthesis.
PROGRESS IN POLYMER SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Dmitry S. Belov, Logesh Mathivathanan, Melanie J. Beazley, William Blake Martin, Konstantin V. Bukhryakov
Summary: The study explores the capability of an iron-based catalyst in performing ring-opening metathesis polymerization of olefins, demonstrating that the use of in situ prepared heteroleptic iron catalysts significantly enhances polymerization rate and selectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Min Li, Yi Zhong, Yunjie Luo, Meng Deng
Summary: In this study, the ferrocenyl functionalized half-sandwich rare-earth metal complexes were synthesized via salt metathesis and addition reactions. The complexes were well-characterized by various analytical techniques, and the solid state structure of complex 1 was determined by X-ray diffraction. Electrochemical study showed that the Fe(ii/iii) couple in these complexes was reversible. Additionally, complex 2 exhibited good controlled polymerization performance.
NEW JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Federica Tufano, Federica Santulli, Fabia Grisi, Marina Lamberti
Summary: Two zinc complexes with NHC ligands were synthesized and studied for their behavior in the Ring-Opening Polymerization of lactides, showing efficiency as initiators with molecular weights dependent on cocatalysts. Microstructural analysis revealed enriched heterotactic PLA, with kinetic parameters compared between different conditions and reactions showing pseudo-first-order dependence on monomer concentration. Reactivity studies aimed to uncover the active species in polymerization processes with different catalytic systems, including zinc complexes alone or in combination with neutral or ionic cocatalysts.
Article
Chemistry, Multidisciplinary
Torsten Thiess, Moritz Ernst, Thomas Kupfer, Holger Braunschweig
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Christian Saalfrank, Felipe Fantuzzi, Thomas Kupfer, Benedikt Ritschel, Kai Hammond, Ivo Krummenacher, Ruediger Bertermann, Raphael Wirthensohn, Maik Finze, Paul Schmid, Volker Engel, Bernd Engels, Holger Braunschweig
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Dipak Kumar Roy, Tobias Troster, Felipe Fantuzzi, Rian D. Dewhurst, Carsten Lenczyk, Krzysztof Radacki, Conor Pranckevicius, Bernd Engels, Holger Braunschweig
Summary: The research focuses on synthesizing and authenticating a heterocyclic compound containing the alkaline earth metal beryllium that exhibits significant antiaromaticity, and delving into its chemical properties in terms of reduction and Lewis-base-coordination chemistry using spectroscopic, structural, and computational techniques.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Inorganic & Nuclear
Ahmed M. Mansour, Krzysztof Radacki, Ola R. Shehab
Summary: Screening for potential antimicrobial drugs using metal-based compounds has shown unexpectedly high hit rates compared to organic compounds. The influence of the axial ligand on the antimicrobial activity against various pathogens and healthy cells was studied, along with compatibility with red blood cells. The stability of the compounds in the presence of a lysozyme protein was also examined for insight into activation profiles.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Asim Kumar Swain, Krzysztof Radacki, Holger Braunschweig, Prince Ravat
Summary: In this manuscript, a stereospecific synthesis of C-2- and C-1-symmetric pyrene-fused [7]helicene compounds 1 and 2 was portrayed, and their properties and enantiomerization barrier were compared.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Correction
Chemistry, Organic
Asim Kumar Swain, Krzysztof Radacki, Holger Braunschweig, Prince Ravat
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Felix Full, Quentin Woelflick, Krzysztof Radacki, Holger Braunschweig, Agnieszka Nowak-Krol
Summary: This article describes the synthesis and characterization of laterally extended azabora[5]-, [6]- and -[7]helicenes using N-heteroaromatic and dibenzo[g,p]chrysene building blocks. The enlargement of the pi-conjugated systems of azaborole helicenes led to compounds with improved optical properties. The combination of lateral and helical extensions resulted in a compound with a high luminescence quantum yield and dissymmetry factor, superior to its non-extended congener. The study suggests that helical and lateral extensions are viable strategies to enhance the features of azaborole helicenes.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Josina L. Bohlen, Lukas Endres, Regina Drescher, Krzysztof Radacki, Maximilian Dietz, Ivo Krummenacher, Holger Braunschweig
Summary: The rare alkyl-substituted boroles were synthesized through aluminum-boron exchange reaction. Sterically crowded aryl groups prevent dimerization and allow access to monomeric derivatives. The alkyl substituents significantly modify the optical and electronic properties compared to the perarylated boroles.
Article
Chemistry, Inorganic & Nuclear
Ahmed M. Mansour, Rabaa M. Khaled, Krzysztof Radacki, Zeina Younes, Mariam Gamal, Beatrice Guirguis, Gamal A. E. Mostafa, Essam A. Ali, Ola R. Shehab
Summary: Human acute monocytic leukaemia cells were more sensitive to a Ru(ii) carbonyl complex (IC50 = 7.13 ± 0.8 μM) with a diphenyl pyridyl phosphine coligand under dark conditions compared to a Mn(i) analogue (IC50 = 54.58 ± 4.1 μM). Both complexes showed no toxicity to healthy mouse bone marrow cells.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Ahmed M. Mansour, Krzysztof Radacki, Gamal A. E. Mostafa, Essam A. Ali, Ola R. Shehab
Summary: This study reports a new catalyst-free [3 + 2] cycloaddition reaction for the synthesis of triazolate complexes. The structures of the complexes and the properties of the reaction products were revealed through theoretical calculations and natural bond analysis.
Article
Materials Science, Multidisciplinary
J. Ruiz-Fuertes, A. Friedrich, N. Garg, V Monteseguro, K. Radacki, D. Errandonea, E. Cavalli, P. Rodriguez-Hernandez, A. Munoz
Summary: In this study, the structure of the potentially scintillating high-pressure phase of beta-MgMoO4 (gamma-MgMoO4) was solved using high-pressure single-crystal x-ray diffraction. It was found that the phase transition is isosymmetrical and involves changes in Mo coordination and crystal axes stretching. The study also investigated the compressibility and electronic structure differences between different phases of MgMoO4, shedding light on the superior scintillation properties of MgWO4 compared to MgMoO4.
Article
Chemistry, Inorganic & Nuclear
Danira A. Habashy, Rabaa M. Khaled, Amr Y. Ahmed, Krzysztof Radacki, Salma K. Ahmed, Engy K. Tharwat, Hana Magdy, Alaa Zeinhom, Ahmed M. Mansour
Summary: The cytotoxicity of two tricarbonyl Mn(I) complexes towards triple negative breast cancer was reported, with compound B showing dose-dependent cytotoxicity and a significant reduction in cell viability when co-treated with paclitaxel.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Nourhan M. Ibrahim, Rabaa M. Khaled, Mohamed A. Ragheb, Krzysztof Radacki, Ahmad M. Farag, Ahmed M. Mansour
Summary: The study examined the release mechanism of CO molecules, photolysis characteristics, and cytotoxicity of [RuCl2(CO)(2)L-R] compounds on breast cancer cells. Illumination increased the cytotoxicity of the compounds, with released CO and metal fragments potentially being the main causes of cytotoxicity.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
Ahmed M. Mansour, Krzysztof Radacki, Ola R. Shehab
Summary: The introduction of a propyl-sulfonic acid group at N1 of the coordinated ligand gives rise to a water-soluble complex that can bind to lysozyme through non-covalent interactions. This complex shows selective moderate toxicity against Cryptococcus neoformans and exhibits no cytotoxicity to healthy HEK293 cells.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
Ahmed M. Mansour, Krzysztof Radacki, Ola R. Shehab
Summary: The lysozyme binding affinity and electronic properties of [ReX (CO)(3)(terpy-κN-2(1),N-2)] (X = Br− and triazolate(COOCH2CH3,CF3)) were reported, with the triazolate compound showing a red shift of the MLCT band in less polar solvents possibly due to negative solvatochromism. The triazolate complex was prepared through a [3 + 2] cyclo-addition click reaction, while the bromo compound reacted with lysozyme forming adducts with Re(CO)(3)(+) fragments.
DALTON TRANSACTIONS
(2021)
