18173-64-3Relevant academic research and scientific papers
Surface oxygen-assisted Pd nanoparticle catalysis for selective oxidation of silanes to silanols
Shimizu, Ken-Ichi,Kubo, Takahiro,Satsuma, Atsushi
, p. 2226 - 2229 (2012)
Just add O2: Based on the fact that an oxygen-adsorbed Pd metal surface shows higher reactivity for water dissociation than a clean Pd surface, carbon-supported Pd nanoparticles (NPs) with surface oxygen atoms were developed as a highly effective and reusable heterogeneous catalyst for selective oxidation of silanes to silanols with water as a green oxidant (see figure). Copyright
Highly Functionalized Tricyclic Oxazinanones via Pairwise Oxidative Dearomatization and N-Hydroxycarbamate Dehydrogenation: Molecular Diversity Inspired by Tetrodotoxin
Good, Steffen N.,Sharpe, Robert J.,Johnson, Jeffrey S.
, p. 12422 - 12425 (2017)
Benzenoids in principle represent attractive and abundant starting materials for the preparation of substituted cyclohexanes; however, the synthetic tools available for overcoming the considerable aromatic energies inherent to these building blocks limit the available product types. In this paper, we demonstrate access to heretofore unknown heterotricyclic structures by leveraging oxidative dearomatization of 2-hydroxymethyl phenols with concurrent N-hydroxycarbamate dehydrogenation using a common oxidant. The pairwise-generated, mutually reactive species then participate in a second stage acylnitroso Diels-Alder cycloaddition. The reaction chemistry of the derived [2.2.2]-oxazabicycles, bearing four orthogonal functional groups and three stereogenic centers, is shown to yield considerable diversity in downstream products. The methodology allows for the expeditious synthesis of a functionalized intermediate bearing structural and stereochemical features in common with the complex alkaloid tetrodotoxin.
?-? Interactions and Bandwidths in "Molecular Metals". A Chemical, Structural, Photoelectron Spectroscopic, and Hartree-Fock-Slater Study of Monomeric and Cofacially Joined Dimeric Silicon Phthalocyanines
Ciliberto, E.,Doris, K. A.,Pietro, W. J.,Reisner, G. M.,Ellis, D. E.,et al.
, p. 7748 - 7761 (1984)
This contribution describes an integrated chemical, physical, and quantum chemical approach to understanding ?-? interactions and tight-binding bandwidths in low-dimensional metallomacrocyclic "metals" via the properties of monomeric and dimeric stack fragments.Thus, electronic structure in the cofacially arrayed phtalocyaninato (Pc) polymer n has been explored through the complexes Si(Pc)(OR)2 and ROSi(Pc)OSi(Pc)OR (R=Si(CH3)2).Improved synthetic and purification procedures are described.Vibrational spectroscopy is employed to assign ROSi and Si(Pc)OSi(Pc) modes, and the results are correlated with data on n.The cofacial dimer crystallizes from chloroform in the orthorhombic space group Pbcn (No. 60) with four molecules in a unit cell of dimensions a=21.670(8), b=13.724(5), and c=23.031(9) Angstroem.Least-squares refinement led to a value for the conventional R index (on F) of 0.127 for 1975 independent reflections having 5 degMoKα0>/=3?(F0).The molecular structure consists of a cofacial (Pc)Si-O-Si(Pc) core of C2 symmetry, having virtually planar phtalocyanine rings, an Si-Si distance (interplanar spacing) of 3.32(1) Angstroem, Si-O-Si=179(1) deg, and a ring-ring staggering angle of 36.6 deg.The Si(CH3)2 capping groups are disordered.Electronic structure in the (phthalocyaninato)silicon monomer and dimer has been studied with first principles discrete variational local exchange (DV-Xα) techniques.These results are combined with transition-state calculations to interpret optical and high resolution He I and He II photoelectron spectroscopic data.While the conventional porphyrinic "four-orbital" model is supported for the low-energy optical transitions (excellent agreement between observed and calculated energies is noted), possible disagreements are noted at higher energies.Calculated (6.8 eV) and observed (6.46 eV) Si(Pc)(OR)2 ionization potentials are in good agreement.The lowest energy PES feature in the dimer is split by 0.29(3) eV.The splitting can be assigned to the cofacial HOMO-HOMO interaction and translates to a tight-binding bandwidth in the polymer of 0.58(6) eV.This result is in favorable agreement with a DV-Xα derived bandwidth of 0.76 eV and a value of 0.60 (6)eV previously obtained from a Drude analysis on I1.12>n.These results argue that the principal charge-transport pathway in the n polymer is via the Pc ? systems and that polaronic band-narrowing effects are minimal.
Catalysis by cationic oxorhenium(v): Hydrolysis and alcoholysis of organic silanes
Corbin, Rex A.,Ison, Elon A.,Abu-Omar, Mahdi M.
, p. 2850 - 2855 (2009)
The cationic [2-(2′-hydroxyphenyl)-2-oxazolinato(-2)]oxorhenium(v) complex 1 promotes oxidative dehydrogenation of organosilanes with water and alcohols in a catalytic manner to give excellent yields of silanols and silyl ethers, respectively. The reactions proceed conveniently under ambient and open-flask conditions with low catalyst loading (≤1 mol%). The scope of the reaction with water is quite broad and includes aliphatic, aromatic, tertiary, secondary and primary silanes. The rate of reaction depends on the catalyst and silane concentrations and kinetic isotope effect measurements demonstrate involvement of the Si-H bond in the activated complex. The most influential factor on the silane affecting reactivity is steric hindrance and a quantitative correlation with the Taft steric parameter (E) is presented. A combination of kinetic data and isotope labelling results are used to discuss plausible mechanisms for the oxidative dehydrogenation reaction pathway.
Hydrogenation and Hydrosilylation of Nitrous Oxide Homogeneously Catalyzed by a Metal Complex
Zeng, Rong,Feller, Moran,Ben-David, Yehoshoa,Milstein, David
, p. 5720 - 5723 (2017)
Due to its significant contribution to stratospheric ozone depletion and its potent greenhouse effect, nitrous oxide has stimulated much research interest regarding its reactivity modes and its transformations, which can lead to its abatement. We report the homogeneously catalyzed reaction of nitrous oxide (N2O) with H2. The reaction is catalyzed by a PNP pincer ruthenium complex, generating efficiently only dinitrogen and water, under mild conditions, thus providing a green, mild methodology for removal of nitrous oxide. The reaction proceeds through a sequence of dihydrogen activation, "O"-atom transfer, and dehydration, in which metal-ligand cooperation plays a central role. This approach was further developed to catalytic O-transfer from N2O to Si-H bonds.
Gold nanoparticles supported on the periodic mesoporous organosilica SBA-15 as an efficient and reusable catalyst for selective oxidation of silanes to silanols
Ma, Lina,Leng, Wenguang,Zhao, Yaopeng,Gao, Yanan,Duan, Hongdong
, p. 6807 - 6810 (2014)
Gold nanoparticles are confined and stabilized within the channels of SBA-15 through the poly(ionic liquid) brushes that are anchored onto the pore walls of SBA-15. The supported gold catalyst exhibited remarkably high catalytic activities for selective oxidation of silanes into silanols using water as an oxidant without the use of organic solvents.
The selective catalytic oxidation of silanes to silanols with H2O2 activated by the Ti-beta zeolite
Adam, Waldemar,Garcia, Hermenegildo,Mitchell, Catherine M.,Saha-Moeller, Chantu R.,Weichold, Oliver
, p. 2609 - 2610 (1998)
Ti-beta catalyses the oxidation of small- and medium-sized silanes to the corresponding silanols by aqueous (30%) H2O2 as oxygen donor with high conversions and excellent selectivity (no disiloxane).
Lewis acid-promoted reactions of γ-lactols with silyl enol ethers - Stereoselective formation of functionalized tetrahydrofuran derivatives
Schmitt, Andreas,Reissig, Hans-Ulrich
, p. 1169 - 1174 (2001)
The monosubstituted γ-lactols 1a, 1b, 1c, and 1d and the disubstituted γ-lactol 1e were converted into tetrahydrofuran derivatives by reaction with typical silyl enol ethers in the presence of Lewis acids. Although the most suitable Lewis acid appears to be zinc chloride, BF3·Et2O or diethylaluminium chloride are also suitable under appropriate conditions. The stereoselectivities of these substitution reactions are similar to those observed with other silylated nucleophiles; however, there are several important differences. A comparison of the diastereoselectivities of different γ-lactols and of various silylated nucleophiles and organometallic compounds will also be presented in this paper.
Oxidation of Triorganosilanes and Related Compounds by Chlorine Dioxide
Grabovskiy, S. A.,Kabal’nova, N. N.
, p. 2391 - 2402 (2022/01/22)
Abstract: Oxidation of triethylsilane, tert-butyldimethylsilane, dimethylphenylsilane, triphenylsilane, 1,1,1,2tetramethyl-2-phenyldisilane, tris(trimethylsilyl)silane, hexamethyldisilane, tetrakis(trimethylsilyl)silane, 1,1,3,3tetraisopropyldisiloxane with chlorine dioxide was carried out. The reaction products of studied triorganosilanes with chlorine dioxide in an acetonitrile solution were the corresponding silanols and siloxanes. A mechanism explaining the formation of products and the observed regularities of the oxidation of silanes with chlorine dioxide has been proposed. A thermochemical analysis of some possible pathways in the gas phase using methods G4, G3, M05, and in an acetonitrile solution by the SMD-M05 method was carried out. The oxidation process can occur both with the participation of ionic and radical intermediates, depending on the structure of the oxidized substrate and medium.
Highly Selective Hydroxylation and Alkoxylation of Silanes: One-Pot Silane Oxidation and Reduction of Aldehydes/Ketones
Luo, Nianhua,Liao, Jianhua,Ouyang, Lu,Wen, Huiling,Zhong, Yuhong,Liu, Jitian,Tang, Weiping,Luo, Renshi
, p. 165 - 171 (2020/01/21)
An efficient chemoselective iridium-catalyzed method for the hydroxylation and alkoxylation of organosilanes to generate hydrogen gas and silanols or silyl ethers was developed. A variety of sterically hindered silanes with alkyl, aryl, and ether groups were tolerated. Furthermore, this atom-economical catalytic protocol can be used for the synthesis of silanediols and silanetriols. A one-pot silane oxidation and chemoselective reduction of aldehydes/ketones was also realized.
