98-80-6Relevant articles and documents
Catalytic phenylborylation reaction by iridium(0) nanoparticles produced from hydridoiridium carborane
Yinghuai, Zhu,Chenyan, Koh,Ang, Thiam Peng,Emi,Monalisa, Winata,Louis, Loo Kui-Jin,Hosmane, Narayan S.,Maguire, John A.
, p. 5756 - 5761 (2008)
Well-dispersed iridium(0) nanoparticles stabilized with the ionic liquid, trihexyltetradecylphosphonium methylsulfonate, [THTdP][MS], have been successfully prepared by reduction of the precursor hydridoiridium carborane, (Ph3P)2Ir(H)-(7,8-nido-C2B9H 11). The iridium nanoparticles were found to be active catalysts for arylborylation, forming boric acids. The activity of the catalyst has been investigated as a function of the activating base, and reaction conditions. The highest yield of 91% was achieved in a microwave reactor using the base, tetra-2-pyridinylpyrazine, in the presence of [THTdP][MS]. The catalytic system could be recycled at least six times with less than a 0.5% loss of activity.
Novel biscapped and monocapped tris(dioxime) Mn(II) complexes: X-ray crystal structure of the first cationic tris(dioxime) Mn(II) complex [Mn(CDOH)3BPh]OH (CDOH2 = 1,2-cyclohexanedione dioxime)
Hsieh, Wen-Yuan,Liu, Shuang
, p. 5034 - 5043 (2006)
This report describes the synthesis and characterization of a series of novel biscapped and monocapped tris-(dioxime) Mn(II) complexes [Mn(dioxime) 3(BR)2] and [Mn(dioxime)3BR]+ (dioxime = cyclohexanedione dioxime (CDOH2) and 1,2-dimethylglyoxyl dioxime (DMGH2); R = Me, n-Bu, and Ph). All tris(dioxime) Mn(II) complexes have been characterized by elemental analysis, IR, UV/vis, cyclic voltammetry, ESI-MS, and, in the cases of [Mn(CDOH)3BPh] OH·CHCl3 and [Mn(CDO)(CDOH)2(BBu(OC 2H5))2], X-ray crystallography. It was found that biscapped Mn(II) complexes [Mn(dioxime)3(BR)2] are not stable in the presence of water and readily hydrolyze to form monocapped cationic complexes [M(dioxime)3BR]+. This instability is most likely caused by mismatch between the size of Mn(II) and the coordination cavity of the biscapped tris(dioxime) ligands. In contrast, monocapped cationic complexes [M(dioxime)3BR]+ are very stable in aqueous solution even in the presence of PDTA (1,2-diaminopropane-N,N,N′,N′- tetraacetic acid) because of the kinetic inertness imposed by the monocapped tris(dioxime) chelators that are able to completely wrap Mn(II) into their N6 coordination cavity. [Mn(CDO)3BPh]OH has a distorted trigonal prismatic coordination geometry, with the Mn(II) being bonded by six imine-N donors. The hydroxyl groups from three dioxime chelating arms form very strong intramolecular hydrogen bonds with the hydroxide counterion so that the structure of [Mn(CDOH)3BPh]OH can be considered as being the clathrochelate with the hydroxide counterion as a cap .
Evaluation of borinic acids as new, fast hydrogen peroxide–responsive triggers
Gatin-Fraudet, Blaise,Ottenwelter, Roxane,Le Saux, Thomas,Norsikian, Stéphanie,Pucher, Mathilde,Lombès, Thomas,Baron, Aurélie,Durand, Philippe,Doisneau, Gilles,Bourdreux, Yann,Iorga, Bogdan I.,Erard, Marie,Jullien, Ludovic,Guianvarc’h, Dominique,Urban, Dominique,Vauzeilles, Boris
, (2021/12/23)
Hydrogen peroxide (H2O2) is responsible for numerous damages when overproduced, and its detection is crucial for a better understanding of H2O2-mediated signaling in physiological and pathological processes. For this purpose, various “off–on” small fluorescent probes relying on a boronate trigger have been prepared, and this design has also been involved in the development of H2O2-activated prodrugs or theranostic tools. However, this design suffers from slow kinetics, preventing activation by H2O2 with a short response time. Therefore, faster H2O2-reactive groups are awaited. To address this issue, we have successfully developed and characterized a prototypic borinic-based fluorescent probe containing a coumarin scaffold. We determined its in vitro kinetic constants toward H2O2-promoted oxidation. We measured 1.9 × 104 M-1·S-1 as a second-order rate constant, which is 10,000-fold faster than its well-established boronic counterpart (1.8 M-1·S-1). This improved reactivity was also effective in a cellular context, rendering borinic acids an advantageous trigger for H2O2-mediated release of effectors such as fluorescent moieties.
Fourth subgroup metal complex with rigid annular bridging structure and application of fourth subgroup metal complex
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Paragraph 0058; 0061-0062, (2021/06/23)
The invention belongs to the technical field of olefin polymerization catalysts, and particularly relates to a fourth subgroup metal complex with a rigid annular bridging structure and an application of the fourth subgroup metal complex. The fourth subgroup metal complex provided by the invention has a structure represented by a formula (A) or a formula (B), X is halogen or alkyl; and M is titanium, zirconium or hafnium. On the basis of a non-metallocene catalyst, a bridging structure in catalyst molecules is improved and upgraded, and a brand-new metal complex with excellent catalytic performance and good high-temperature tolerance is designed; when the fourth subgroup metal complex is used as a main catalyst to catalyze olefin polymerization reaction, under the activation action of a small amount of mixed cocatalyst, the fourth subgroup metal complex can efficiently catalyze the copolymerization reaction of ethylene and alpha-olefin to obtain polyolefin with high molecular weight and high comonomer insertion rate.
Detection of hydrogen peroxide using dioxazaborocanes: elucidation of the sensing mechanism at the molecular level by NMR and XPS measurements
Caron, Thomas,Palmas, Pascal,Frénois, Céline,Méthivier, Christophe,Pasquinet, Eric,Pradier, Claire-Marie,Serein-Spirau, Fran?oise,Hairault, Lionel,Montméat, Pierre
, p. 4114 - 4121 (2020/03/19)
A fluorescent dioxazaborocane was synthesised and characterized, in order to study its turn-off sensing process for hydrogen peroxide detection. The exposure of the dioxazaborocane to diluted vapours of H2O2 led to a strong non reversible quenching of the fluorescence. Both NMR and XPS analyses were carried out before and after exposure of dioxazaborocane to H2O2 vapours. They unequivocally show that the boron atom is oxidised in the film with cleavage of the N-B dative bond. Identification of products such as phenol and boric acid by NMR, supported by consistent XPS data, enabled the whole reaction sequence that explains the fluorescence quenching of dioxazaborocane upon H2O2 exposure to be described accurately. Direct hydrolysis of dioxazaborocane to diol, without oxidation, was only marginally observed.
Pd- And Ni-Based Systems for the Catalytic Borylation of Aryl (Pseudo)halides with B2(OH)4
Munteanu, Charissa,Spiller, Taylor E.,Qiu, Jun,Delmonte, Albert J.,Wisniewski, Steven R.,Simmons, Eric M.,Frantz, Doug E.
, p. 10334 - 10349 (2020/09/18)
Despite recent advancements in metal-catalyzed borylations of aryl (pseudo)halides, there is a continuing need to develop robust methods to access both early-stage and late-stage organoboron intermediates amendable for further functionalization. In particular, the development of general catalytic systems that operate under mild reaction conditions across a broad range of electrophilic partners remains elusive. Herein, we report the development and application of three catalytic systems (two Pd-based and one Ni-based) for the direct borylation of aryl (pseudo)halides using tetrahydroxydiboron (B2(OH)4). For the Pd-based catalyst systems, we have identified general reaction conditions that allow for the sequestration of halide ions through simple precipitation that results in catalyst loadings as low as 0.01 mol % (100 ppm) and reaction temperatures as low as room temperature. We also describe a complementary Ni-based catalyst system that employs simple unligated Ni(II) salts as an inexpensive alternative to the Pd-based systems for the borylation of aryl (pseudo)halides. Extrapolation of all three systems to a one-pot tandem borylation/Suzuki-Miyaura cross-coupling is also demonstrated on advanced intermediates and drug substances.
Boronic Ester Based Vitrimers with Enhanced Stability via Internal Boron-Nitrogen Coordination
Zhang, Xiaoting,Wang, Shujuan,Jiang, Zikang,Li, Yu,Jing, Xinli
, p. 21852 - 21860 (2021/01/11)
Boron-containing polymers have many applications resulting from their prominent properties. Organoboron species with reversible B-O bonds have been successfully employed for the fabrication of various self-healing/healable and reprocessable polymers. However, the application of the polymers containing boronic ester or boroxine linkages is limited because of their instability to water. Herein, we report the hydrolytic stability and dynamic covalent chemistry of the nitrogen-coordinating cyclic boronic diester (NCB) linkages, and a new class of vitrimers based on NCB linkages is developed through the chemical reactions of reactive hydrogen with isocyanate. Thermodynamic and kinetic studies demonstrated that NCB linkages exhibit enhanced water and heat resistance, whereas the exchange reactions between NCB linkages can take place upon heating without any catalyst. The model compounds of NCBC-X1 and NCBC-X2 containing a urethane group and urea group, respectively, also showed higher hydrolytic stability compared to that of conventional boronic esters. Polyurethane vitrimers and poly(urea-urethane) vitrimers based on NCB linkages exhibited excellent solvent resistance and mechanical properties like general thermosets, which can be repaired, reprocessed, and recycled via the transesterification of NCB linkages upon heating. Especially, vitrimers based on NCB linkages presented improved stability to water and heat compared to those through conventional boronic esters because of the existence of N → B internal coordination. We anticipate that this work will provide a new strategy for designing the next generation of sustainable materials.
Bimetal complex with aryloxy ether skeleton, and preparation method and application thereof
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Paragraph 0129; 0132; 0136; 0138; 0174-0175; 0177, (2020/11/26)
The invention provides a bimetallic complex with an aryloxy ether skeleton, and a preparation method and application of the bimetallic complex. The bimetallic complex has a structural expression as shown in the specification. A catalytic system of the bimetallic complex shows very good catalytic activity and thermal stability when being used for catalyzing olefin homopolymerization or olefin/alphaolefin copolymerization reactions, and a polymerization product generated by catalysis has relatively high molecular weight and a high alpha-olefin insertion rate and has a very good industrial application prospect.
Linking Molecular Behavior to Macroscopic Properties in Ideal Dynamic Covalent Networks
Marco-Dufort, Bruno,Iten, Ramon,Tibbitt, Mark W.
supporting information, p. 15371 - 15385 (2020/10/20)
Dynamic covalent networks (DCvNs) are increasingly used in advanced materials design with applications ranging from recyclable thermosets to self-healing hydrogels. However, the relationship between the underlying chemistry at the junctions of DCvNs and their macroscopic properties is still not fully understood. In this work, we constructed a robust framework to predict how complex network behavior in DCvNs emerges from the chemical landscape of the dynamic chemistry at the junction. Ideal dynamic covalent boronic ester-based hydrogels were used as model DCvNs. We developed physical models that describe how viscoelastic properties, as measured by shear rheometry, are linked to the molecular behavior of the dynamic junction, quantified via fluorescence and NMR spectroscopy and DFT calculations. Additionally, shear rheometry was combined with Transition State Theory to quantify the kinetics and thermodynamics of network rearrangements, enabling a mechanistic understanding including preferred reaction pathways for dynamic covalent chemistries. We applied this approach to corroborate the "loose-bolt"postulate for the reaction mechanism in Wulff-type boronic acids. These findings, grounded in molecular principles, advance our understanding and rational design of dynamic polymer networks, improving our ability to predict, design, and leverage their unique properties for future applications.
Erratum: Linking molecular behavior to macroscopic properties in ideal dynamic covalent networks (Journal of the American Chemical Society (2020) 142: 36 (15371-15385) DOI: 10.1021/jacs.0c06192)
Iten, Ramon,Marco-Dufort, Bruno,Tibbitt, Mark W.
supporting information, p. 18730 - 18731 (2020/11/19)
The "concentration of functional groups, c,"was defined incorrectly on page S18 of the Supporting Information. The (Table Presented) correct definition is as follows: c is the concentration of functional groups of one of the two network components, assuming that both components are present in equal amounts. Therefore, in a network formed from tetrafunctional macromers (f = 4) and where the total molar concentration of macromers is [PEG], c = f [PEG]/2 = 4[PEG]/2 = 2[PEG]. In the original Supporting Information, we took c as the total concentration of functional groups in the network, resulting in c = 4[PEG]. This formula was incorrect and resulted in erroneous values for select Keq or Gp data reported in Table 1 (page 15374) and Figure 8 (page 15381). The corrected Table 1 and Figure 8 are shown below, and the SI has been corrected accordingly. In addition, some of these data that are quoted in the article should be changed as follows (with the corrected values highlighted in bold). On page 15374: "Keq,c = 37.5 when c = 0.02 M,""Keq was determined to be 540 ± 65. [?] corresponding to Gp = 10.9 ± 2.0 kPa,"and "Keq was quantified as 277 ± 37 from NMR and 323 from DFT, corresponding to Gp = 8.0 ± 0.8 and 9.0 kPa, respectively."On page 15381: "The rheometric data exhibited a similar increase in Keq from 75 at pH 6 to 10750 at pH 9 (Figure 8c)"and "At pH 9, Keq = 1126 ± 108 and 565 (from spectroscopy and rheology, respectively) and then decreased sharply at pH 10 to Keq = 112 and 120 (Figure 8e,f)."On page 15373 (in the Figure 2 caption): "Keq = 540 ± 65."'Table Presented' These corrections do not affect any of the conclusions of the article but only the exact value of select parameters. We apologize for these errors and for any inconvenience caused to the readers. ? Associated Content: ? Supporting Information The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.0c10406. Synthesis, sample preparation, computational and experimental methods, and model descriptions (PDF). (Figure Presented).
