keyword
https://read.qxmd.com/read/38415944/a-powerful-strategy-for-synthesizing-block-copolymers-via-bimetallic-synergistic-catalysis
#21
JOURNAL ARTICLE
Xiang-Yu Fu, Tian-Jun Yue, Bai-Hao Ren, Hai Wang, Wei-Min Ren, Xiao-Bing Lu
Block copolymers, comprising polyether and polyolefin segments, are an important and promising category of functional materials. However, the lack of efficient strategies for the construction of polyether-b-polyolefin block copolymers have hindered the development of these materials. Herein, we propose a simple and efficient method to obtain various block copolymers through the copolymerization of epoxides and acrylates via bimetallic synergistic catalysis. The copolymerization of epoxides and acrylates proceeds in a sequence-controlled manner, where the epoxides-involved homo- or copolymerization occurs first, followed by the homopolymerization of acrylates initiated by the alkoxide species from the propagating polymer chain, thus yielding copolymers with a block structure...
February 28, 2024: Angewandte Chemie
https://read.qxmd.com/read/38400593/bis-alkoxide-dysprosium-iii-crown-ether-complexes-exhibit-tunable-air-stability-and-record-energy-barrier
#22
JOURNAL ARTICLE
Wen-Jie Xu, Qian-Cheng Luo, Zi-Han Li, Yuan-Qi Zhai, Yan-Zhen Zheng
High-performance and air-stable single-molecule magnets (SMMs) can offer great convenience for the fabrication of information storage devices. However, the controversial requisition of high stability and magnetic axiality is hard to balance for lanthanide-based SMMs. Here, a family of dysprosium(III) crown ether complexes possessing hexagonal-bipyramidal (pseudo-D6h symmetry) local coordination geometry with tunable air stability and effective energy barrier for magnetization reversal (Ueff ) are shown. The three complexes share the common formula of [Dy(18-C-6)L2 ][I3 ] (18-C-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane; L = I, 1; L = Ot Bu 2 and L = 1-AdO 3)...
February 23, 2024: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
https://read.qxmd.com/read/38391463/design-of-nickel-containing-nanocomposites-based-on-ordered-mesoporous-silica-synthesis-structure-and-methylene-blue-adsorption
#23
JOURNAL ARTICLE
Tatyana Kouznetsova, Andrei Ivanets, Vladimir Prozorovich, Polina Shornikova, Lizaveta Kapysh, Qiang Tian, László Péter, László Trif, László Almásy
Mesoporous materials containing heteroelements have a huge potential for use as catalysts, exchangers, and adsorbents due to their tunable nanometer-sized pores and exceptionally large internal surfaces accessible to bulky organic molecules. In the present work, ordered mesoporous silica containing Ni atoms as active sites was synthesized by a new low-temperature method of condensation of silica precursors on a micellar template from aqueous solutions in the presence of nickel salt. The homogeneity of the resulting product was achieved by introducing ammonia and ammonium salt as a buffer to maintain a constant pH value...
February 6, 2024: Gels
https://read.qxmd.com/read/38381590/synthesis-and-insecticidal-evaluation-of-3-5-dicyanopyridines-against-cotton-aphids-via-microwave-assisted-multicomponent-reactions
#24
JOURNAL ARTICLE
Mohamed Ahmed Gad, Hany M Abd El-Lateef, Mai M Khalaf, Mohamed Gouda, Antar Ahmed Abdelhamid, Amer Anwar Amer, Ali Moustafa Drar, Abdelrahim Fathy Ismail
Certain 2-amino-6-alkoxy-4-arylpyridine-3,5-dicyanide 1a-e were prepared via a straightforward process using microwave technology rather than conventional methods. This involved reaction of arylidenemalononitrile thru propanedinitrile in the occurrence of sodium alkoxide under MW. While, their positional isomer 4-amino-6-alkoxy-2-arylpyridine-3,5-dicyanide 3a-j have been separated from the reaction of aryl aldehydes with 2-aminoprop-1-ene-1,1,3-tricarbonitrile 2 in the presence of sodium alkoxide using microwave technic...
February 21, 2024: Chemistry & Biodiversity
https://read.qxmd.com/read/38372037/dial-a-base-mechanochemical-synthesis-of-n-heterocyclic-carbene-copper-complexes
#25
JOURNAL ARTICLE
Dawid J Babula, Rex S C Charman, Josie A Hobson, Mary F Mahon, David J Liptrot
Liquid assisted ball milling of [NHC]HBr (NHC = N-heterocyclic carbene) salts with copper(I) chloride, and a range of alkali metal complexes was shown to efficiently produce (NHC)CuX (NHC = normal or RE-NHC, X = halide, alkoxide, amide, alkyl, aryl; RE-NHC = ring-expanded NHC).
February 19, 2024: Dalton Transactions: An International Journal of Inorganic Chemistry
https://read.qxmd.com/read/38367253/direct-synthesis-of-tertiary-phosphines-via-alkoxide-mediated-deborylative-phosphination-of-organoboronates
#26
JOURNAL ARTICLE
Huaxing Sun, Jing Wang, Zihang Du, Kun Zhang, Jiefeng Hu, Su Jing
The direct transformation of alkylboron has emerged as a versatile and powerful methodology for creating carbon-carbon and carbon-heteroatom bonds. However, its potential application in the formation of carbon and phosphorus remains unexplored. In this study, we present an alkoxide base-promoted reaction system that enables deborylative phosphination of benzylic organoboronates and geminal bis(boronates) via selective C-B bond cleavage. This approach allows for the synthesis of valuable tertiary phosphines in good yields under mild conditions...
February 17, 2024: Organic Letters
https://read.qxmd.com/read/38364313/preparation-x-ray-characterization-and-reactivity-of-the-rod-like-and-angular-germanium-and-titanium-iv-capped-iron-ii-bis-clathrochelates-and-their-mono-and-bis-capped-semi-clathrochelate-precursors
#27
JOURNAL ARTICLE
Alexander S Chuprin, Svetlana A Belova, Anna V Vologzhanina, Pavel V Dorovatovskii, Yan Z Voloshin
Transmetalation of the bis{triethylantimony(V)}-capped iron(II) tris-α-dioximate with n -butylboronic acid afforded the mixed antimony, boron cross-linked clathrochelate with single reactive antimony(V)-based apical fragment. This macrobicyclic precursor easily underwent the transmetalation reactions with germanium and titanium(IV) alkoxides to give the rod-like and angular FeII 2 MIV -trinuclear bis-clathrochelates. Those of the aforementioned diantimony(V)-capped complex with 3- and 4-carboxyphenylboronic acids afforded the monoboron-capped iron(II) semiclathrochelates, undergoing a double-cyclization (macrobicyclization) with germanium- and titanium(IV)-based capping agents...
February 16, 2024: Inorganic Chemistry
https://read.qxmd.com/read/38359082/room-temperature-copper-catalyzed-etherification-of-aryl-bromides
#28
JOURNAL ARTICLE
Michael Joseph Strauss, Megan E Greaves, Seoung-Tae Kim, Christiana N Teijaro, Michael A Schmidt, Paul M Scola, Stephen L Buchwald
We disclose the development of a Cu-catalyzed C-O coupling method utilizing a new N1,N2-diarylbenzene-1,2-diamine ligand, L8.  Under optimized reaction conditions, structurally diverse aryl and heteroaryl bromides underwent efficient coupling with a variety of alcohols at room temperature using an L8-based catalyst. Notably, the L8-derived catalyst exhibited enhanced activity when compared to the L4-based system previously disclosed for C-N coupling, namely the ability to functionalize aryl bromides containing acidic functional groups...
February 15, 2024: Angewandte Chemie
https://read.qxmd.com/read/38343953/a-spin-frustrated-azide-and-alkoxide-bridged-heterobimetallic-mixed-valence-mn-ii-mn-iii-2-ni-ii-4-disc-with-s-17-2-or-19-2
#29
JOURNAL ARTICLE
Jayasree Kumar, Ibtesham Tarannum, Saurabh Kumar Singh, Kartik Chandra Mondal
Seven-membered homometallic FeIII 7 , MnIII 3 MnII 4 coordination clusters were previously reported to be spin-frustrated molecular discs. Herein, a mixed bimetallic and mixed-valence dicationic [MnII MnIII 2 NiII 4 (N3 )4 (hmp)10 ](NO3 )2 ( 1 2+ (NO 3 ) 2 ) was isolated in pure form without scrambling of Ni/Mn ions. It was structurally characterized by single-crystal X-ray single-crystal diffraction. The presence of MnII ions at the center of the disc has been confirmed by EPR measurements. The magnetic studies suggest that complex 1 2+ (NO 3 ) 2 possesses spin frustration with spin ground states S = 17/2 and 19/2, which has been studied and supported by DFT calculation...
February 6, 2024: ACS Omega
https://read.qxmd.com/read/38259134/spectroscopic-and-theoretical-investigation-of-high-spin-square-planar-and-trigonal-fe-ii-complexes-supported-by-fluorinated-alkoxides
#30
JOURNAL ARTICLE
Léa A Toubiana, Adam Valaydon-Pillay, Jessica K Elinburg, Jeffrey W Bacon, Andrew Ozarowski, Linda H Doerrer, Sebastian A Stoian
The electronic structures and spectroscopic behavior of three high-spin FeII complexes of fluorinated alkoxides were studied: square-planar {K(DME)2 }2 [Fe(pinF )2 ] ( S ) and quasi square-planar {K( C 222)}2 [Fe(pinF )2 ] ( S' ) and trigonal-planar {K(18C6)}[Fe(OC4 F9 )3 ] ( T ) where pinF = perfluoropinacolate and OC4 F9 = tris -perfluoro- t -butoxide. The zero-field splitting (ZFS) and hyperfine structure parameters of the S = 2 ground states were determined using field-dependent 57 Fe Mössbauer and high-field and -frequency electron paramagnetic resonance (HFEPR) spectroscopies...
January 23, 2024: Inorganic Chemistry
https://read.qxmd.com/read/38258160/ultrathin-flexible-encapsulation-materials-based-on-al-2-o-3-alucone-nanolaminates-for-improved-electrical-stability-of-silicon-nanomembrane-based-mos-capacitors
#31
JOURNAL ARTICLE
Zhuofan Wang, Hongliang Lu, Yuming Zhang, Chen Liu, Haonan Zhang, Yanhao Yu
Ultrathin flexible encapsulation (UFE) using multilayered films has prospects for practical applications, such as implantable and wearable electronics. However, existing investigations of the effect of mechanical bending strains on electrical properties after the encapsulation procedure provide insufficient information for improving the electrical stability of ultrathin silicon nanomembrane (Si NM)-based metal oxide semiconductor capacitors (MOSCAPs). Here, we used atomic layer deposition and molecular layer deposition to generate 3...
December 24, 2023: Micromachines
https://read.qxmd.com/read/38241170/heterometal-dopant-changes-the-mechanism-of-proton-coupled-electron-transfer-at-the-polyoxovanadate-alkoxide-surface
#32
JOURNAL ARTICLE
Shannon E Cooney, M Rebecca A Walls, Eric Schreiber, William W Brennessel, Ellen M Matson
The transfer of two H-atom equivalents to the titanium-doped polyoxovanadate-alkoxide, [TiV5 O6 (OCH3 )13 ], results in the formation of a V(III)-OH2 site at the surface of the assembly. Incorporation of the group (IV) metal ion results in a weakening of the O-H bonds of [TiV5 O5 (OH2 )(OCH3 )13 ] in comparison to its homometallic congener, [V6 O6 (OH2 )(OCH3 )12 ], resembling more closely the thermodynamics reported for the one-electron reduced derivative, [V6 O6 (OH2 )(OCH3 )12 ]1- . An analysis of early time points of the reaction of [TiV5 O6 (OCH3 )13 ] and 5,10-dihydrophenazine reveals the formation of an oxidized substrate, suggesting that proton-coupled electron transfer proceeds via initial electron transfer from substrate to cluster prior to proton transfer...
January 19, 2024: Journal of the American Chemical Society
https://read.qxmd.com/read/38237297/a-dual-mode-fluorescence-and-colorimetric-sensing-platform-for-efficient-detection-of-ofloxacin-in-aquatic-products-using-iron-alkoxide-nanozyme
#33
JOURNAL ARTICLE
Xiaodan Ding, Waqas Ahmad, Yawen Rong, Jizhong Wu, Qin Ouyang, Quansheng Chen
Trace detection of ofloxacin (OFL) with high sensitivity, reliability, and visual clarity is challenging. To address this, a novel dual-modal aptasensor with fluorescence-colorimetric capabilities was designed that exploit the target-induced release of 3,3',5,5'-tetramethylbenzidine (TMB) molecules from aptamer-gated mesoporous silica nanoparticles (MSNs), the oxidase-like activity of iron alkoxide (IA) nanozyme, and the fluorescence attributes of core-shell upconversion nanoparticles. Therefore, the study reports a dual mode detection, with a fluorescence detection range for OFL spanning from 0...
January 13, 2024: Food Chemistry
https://read.qxmd.com/read/38189606/role-of-a-cyclopentadienyl-ligand-in-a-heteroleptic-alkoxide-precursor-in-atomic-layer-deposition
#34
JOURNAL ARTICLE
Hwi Yoon, Yujin Lee, Ga Yeon Lee, Seunggi Seo, Bo Keun Park, Taek-Mo Chung, Il-Kwon Oh, Hyungjun Kim
Alkoxide precursors have been highlighted for depositing carbon-free films, but their use in Atomic Layer Deposition (ALD) often exhibits a non-saturated growth. This indicates no self-limiting growth due to the chain reaction of hydrolysis or ligand decomposition caused by β-hydride elimination. In the previous study, we demonstrated that self-limiting growth of ALD can be achieved using our newly developed precursor, hafnium cyclopentadienyl tris(N-ethoxy-2,2-dimethyl propanamido) [HfCp(edpa)3]. To elucidate the growth mechanism and the role of cyclopentadienyl (Cp) ligand in a heteroleptic alkoxide precursor, herein, we compare homoleptic and heteroleptic Hf precursors consisting of N-ethoxy-2,2-dimethyl propanamido (edpa) ligands with and without cyclopentadienyl ligand-hafnium tetrakis(N-ethoxy-2,2-dimethyl propanamido) [Hf(edpa)4] and HfCp(edpa)3...
January 14, 2024: Journal of Chemical Physics
https://read.qxmd.com/read/38179511/the-structures-and-reactivity-of-nhc-supported-copper-i-triphenylgermyls
#35
JOURNAL ARTICLE
Rex S C Charman, Nick J Evans, Laura E English, Samuel E Neale, Petra Vasko, Mary F Mahon, David J Liptrot
Deprotonation of triphenyl germane with NHC-supported copper alkoxides afforded four novel (NHC)CuGePh3 complexes. Of these, (IPr)CuGePh3 (IPr = :C{N(2,6-iPr2 C6 H3 )CH}2 ) was selected for further investigation. Analysis by EDA-NOCV indicates it to be a germyl nucleophile and its σ-bond metathesis reaction with a range of p-block halides confirmed it to be a convenient source of [Ph3 Ge]- . The Cu-Ge bond of (IPr)CuGePh3 underwent π-bond insertions with t BuNCS, CS2 , and PhNCO to furnish a series of germyl substituted carboxylate derivatives, (IPr)CuXC(Y)GePh3 (X = S, NPh; Y = S, N t Bu, O), which were structurally characterised...
January 3, 2024: Chemical Science
https://read.qxmd.com/read/38148254/visible-light-promoted-reduction-of-epoxides-hydroxysulfonates-and-halohydrines-with-alkyltitanium-alkoxides
#36
JOURNAL ARTICLE
Artyom Mikhaliov, Aliaksei Flerko, Dziyana Atroshchanka, Aliaksei Harakhouski, Arsenii Budko, Kirill Stasko, Andrei Bialkevich, Siarhei Shepialevich, Yahor Rusakovich, Alaksiej Hurski
Alkyltitanium alkoxides generally serve as nucleophiles in reactions with carbonyl compounds and cross-coupling. Their application as reductants is known but remains underdeveloped. Here, we report that irradiation with visible light makes these organometallic compounds efficient reducing agents for the dehalogenation of 1,2- and 1,3-haloalcohols. This reaction was utilized for the reduction of epoxides and sulfonates, which proceeded through a sequence of the in situ halohydrin formation and photochemical dehalogenation...
December 26, 2023: Organic Letters
https://read.qxmd.com/read/38134677/ball-in-ball-nis-2-cos-2-heterojunction-driven-by-kirkendall-effect-for-high-performance-mg-2-li-hybrid-batteries
#37
JOURNAL ARTICLE
Ximin Ling, Wutao Wei, Changwei Shan, Xuyan Qin, Mingjie Song, Zhao Liu, Liwei Mi
Mg2+ /Li+ hybrid batteries (MLHBs), which support the rapid insertion and removal of Mg2+ /Li+ bimetallic ions, are promising energy storage systems. Inspired by the Kirkendall effect, ball-in-ball bimetallic sulfides with heterostructures were prepared as cathode materials for the MLHBs. First, a nickel-cobalt precursor (NiCo-X precursor) with three-dimensional (3D) nanosheets on its surface was prepared using a solvothermal method based on the association reaction between alkoxide molecules. Subsequently, the NiCo-X precursor was vulcanized at high temperature using the potential energy difference as the driving force to successfully prepare NiS2 @CoS2 core-shell hollow spheres...
December 13, 2023: Journal of Colloid and Interface Science
https://read.qxmd.com/read/38125977/evaluating-heterodinuclear-mg-ii-m-ii-m-mn-fe-ni-cu-and-zn-catalysts-for-the-chemical-recycling-of-poly-cyclohexene-carbonate
#38
JOURNAL ARTICLE
Madeleine L Smith, Thomas M McGuire, Antoine Buchard, Charlotte K Williams
Polymer chemical recycling to monomers (CRM) is important to help achieve a circular plastic economy, but the "rules" governing catalyst design for such processes remain unclear. Here, carbon dioxide-derived polycarbonates undergo CRM to produce epoxides and carbon dioxide. A series of dinuclear catalysts, Mg(II)M(II) where M(II) = Mg, Mn, Fe, Co, Ni, Cu, and Zn, are compared for poly(cyclohexene carbonate) depolymerizations. The recycling is conducted in the solid state, at 140 °C monitored using thermal gravimetric analyses, or performed at larger-scale using laboratory glassware...
December 15, 2023: ACS Catalysis
https://read.qxmd.com/read/38118120/unexpected-periodicity-in-cationic-group-5-initiators-for-the-ring-opening-polymerization-of-lactones
#39
JOURNAL ARTICLE
Antoine Buchard, Matthew G Davidson, Gerrit Gobius du Sart, Matthew D Jones, Gabriele Kociok-Köhn, Strachan N McCormick, Paul McKeown
ε-Caprolactone (ε-CL) adducts of cationic, amine tris(phenolate)-supported niobium(V) and tantalum(V) ethoxides initiate the ring-opening polymerization of lactones. The Ta(V) species prepared and applied catalytically herein exhibits higher activity in the ring-opening polymerization (ROP) of ε-caprolactone than the previously reported, isostructural Nb(V) complex, contradicting literature comparisons of Nb(V)- and Ta(V)-based protocols. Both systems also initiate the ROP of δ-valerolactone and rac -β-butyrolactone, kinetic studies confirming retention of higher activity by the Nb congener...
December 20, 2023: Inorganic Chemistry
https://read.qxmd.com/read/38117662/selective-1-2-hydroarylation-alkenylation-of-gem-difluoroalkenes-to-access-cf2h-motifs
#40
JOURNAL ARTICLE
Leroy Qi Hao Lin, Ángel Rentería-Gómez, Robert T Martin, Ying-Qi Zhang, Kelvin Zhi Wei Ong, Adam B Parris, Osvaldo Gutierrez, Ming Joo Koh
An emerging class of C-C coupling transformations that furnish drug-like building blocks involves catalytic hydrocarbonation of alkenes. However, despite notable advances in the field, hydrocarbon addition to gem-difluoroalkenes without additional electronic activation remains largely unsuccessful. This owes partly to poor reactivity and the propensity of difluoroalkenes to undergo defluorinative side reactions. Here, we report a nickel catalytic system that promotes efficient 1,2-selective hydroarylation and hydroalkenylation, suppressing defluorination and providing straightforward access to a diverse assortment of prized organofluorides bearing difluoromethyl-substituted carbon centers...
December 20, 2023: Angewandte Chemie
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