1829-41-0Relevant articles and documents
MODIFICATION OF OLEFIN POLYMERIZATION CATALYSTS II. A 29Si NMR STUDY ON THE COMPLEXATION OF SILYL ETHERS WITH TRIETHYLALUMINIUM
Sormunen, Pekka,Iiskola, Eero,Vaehaesarja, Eila,Pakkanen, Tuula T.,Pakkanen, Tapani A.
, p. 327 - 332 (1987)
The effect of complexation with a Lewis acid, AlEt3, and alkylation on the chemical shift of silyl ethers has been studied using 29Si NMR spectroscopy.The substitution of a methoxy group for an ethyl group shifts the 29Si signal on an average by 36.9 ppm to lower field, and the signal for the complexed silyl ether is usually shifted to lower field compared with that for the uncomplexed ether, the shift varying between -1.4 and 18.1 ppm.Dynamic processes have been observed for some of the spectra; this is interpreted in terms of competition of Al acceptors for the several silyl ethers simultaneous present.
Metal-free hydrogen evolution cross-coupling enabled by synergistic photoredox and polarity reversal catalysis
Cao, Jilei,Lu, Kanghui,Ma, Lishuang,Yang, Xiaona,Zhou, Rong
supporting information, p. 8988 - 8994 (2021/11/23)
A synergistic combination of photoredox and polarity reversal catalysis enabled a hydrogen evolution cross-coupling of silanes with H2O, alcohols, phenols, and silanols, which afforded the corresponding silanols, monosilyl ethers, and disilyl ethers, respectively, in moderate to excellent yields. The dehydrogenative cross-coupling of Si-H and O-H proceeded smoothly with broad substrate scope and good functional group compatibility in the presence of only an organophotocatalyst 4-CzIPN and a thiol HAT catalyst, without the requirement of any metals, external oxidants and proton reductants, which is distinct from the previously reported photocatalytic hydrogen evolution cross-coupling reactions where a proton reduction cocatalyst such as a cobalt complex is generally required. Mechanistically, a silyl cation intermediate is generated to facilitate the cross-coupling reaction, which therefore represents an unprecedented approach for the generation of silyl cationviavisible-light photoredox catalysis.
Selective Electrochemical Hydrolysis of Hydrosilanes to Silanols via Anodically Generated Silyl Cations
Liang, Hao,Wang, Lu-Jun,Ji, Yun-Xing,Wang, Han,Zhang, Bo
supporting information, p. 1839 - 1844 (2020/12/01)
The first electrochemical hydrolysis of hydrosilanes to silanols under mild and neutral reaction conditions is reported. The practical protocol employs commercially available and cheap NHPI as a hydrogen-atom transfer (HAT) mediator and operates at room temperature with high selectivity, leading to various valuable silanols in moderate to good yields. Notably, this electrochemical method exhibits a broad substrate scope and high functional-group compatibility, and it is applicable to late-stage functionalization of complex molecules. Preliminary mechanistic studies suggest that the reaction appears to proceed through a nucleophilic substitution reaction of an electrogenerated silyl cation with H2O.
Self-Assembled Open Porous Nanoparticle Superstructures
Liu, Rongjuan,Wei, Jingjing,Wei, Yanze,Yang, Zhijie,Zhang, Fenghua
supporting information, (2021/08/20)
Imparting porosity to inorganic nanoparticle assemblies to build up self-assembled open porous nanoparticle superstructures represents one of the most challenging issues and will reshape the property and application scope of traditional inorganic nanoparticle solids. Herein, we discovered how to engineer open pores into diverse ordered nanoparticle superstructures via their inclusion-induced assembly within 1D nanotubes, akin to the molecular host-guest complexation. The open porous structure of self-assembled composites is generated from nonclose-packing of nanoparticles in 1D confined space. Tuning the size ratios of the tube-to-nanoparticle enables the structural modulation of these porous nanoparticle superstructures, with symmetries such as C1, zigzag, C2, C4, and C5. Moreover, when the internal surface of the nanotubes is blocked by molecular additives, the nanoparticles would switch their assembly pathway and self-assemble on the external surface of the nanotubes without the formation of porous nanoparticle assemblies. We also show that the open porous nanoparticle superstructures can be ideal candidate for catalysis with accelerated reaction rates.
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.
Half-sandwich ruthenium(ii) complexes with tethered arene-phosphinite ligands: Synthesis, structure and application in catalytic cross dehydrogenative coupling reactions of silanes and alcohols
González-Fernández, Rebeca,Crochet, Pascale,Cadierno, Victorio
, p. 210 - 222 (2019/12/28)
The preparation of the tethered arene-ruthenium(ii) complexes [RuCl2{η6:κ1(P)-C6H5(CH2)nOPR2}] (R = Ph, n = 1 (9a), 2 (9b), 3 (9c); R = iPr, n = 1 (10a), 2 (10b), 3 (10c)) from the corresponding phosphinite ligands R2PO(CH2)nPh (R = Ph, n = 1 (1a), 2 (1b), 3 (1c); R = iPr, n = 1 (2a), 2 (2b), 3 (2c)) is presented. Thus, in a first step, the treatment at room temperature of tetrahydrofuran solutions of dimers [{RuCl(μ-Cl)(η6-arene)}2] (arene = p-cymene (3), benzene (4)) with 1-2a-c led to the clean formation of the corresponding mononuclear derivatives [RuCl2(η6-p-cymene){R2PO(CH2)nPh}] (5-6a-c) and [RuCl2(η6-benzene){R2PO(CH2)nPh}] (7-8a-c), which were isolated in 66-99% yield. The subsequent heating of 1,2-dichloroethane solutions of these compounds at 120 °C allowed the exchange of the coordinated arene. The substitution process proceeded faster with the benzene derivatives 7-8a-c, from which complexes 9-10a-c were generated in 61-82% yield after 0.5-10 h of heating. The molecular structures of [RuCl2(η6-p-cymene){iPr2PO(CH2)3Ph}] (6c) and [RuCl2{η6:κ1(P)-C6H5(CH2)nOPiPr2}] (n = 1 (10a), 2 (10b), 3 (10c)) were unequivocally confirmed by X-ray diffraction methods. In addition, complexes [RuCl2{η6:κ1(P)-C6H5(CH2)nOPR2}] (9-10a-c) proved to be active catalysts for the dehydrogenative coupling of hydrosilanes and alcohols under mild conditions (r.t.). The best results were obtained with [RuCl2{η6:κ1(P)-C6H5(CH2)3OPiPr2}] (10c), which reached TOF and TON values up to 117 600 h-1 and 57 000, respectively.
Metal-free visible-light-mediated aerobic oxidation of silanes to silanols
Wang, Jing,Li, Bin,Liu, Li-Chuan,Jiang, Chenran,He, Tao,He, Wei
, p. 1594 - 1599 (2018/08/22)
Oxidation of silanes into silanols using water/air has attracted considerable attention. The known methods with no exception required a metal catalyst. Herein we report the first metal-free method: 2 mol% Rose Bengal as the catalyst, air (O2) as the oxidant, water as the additive and under visible light irradiation. While this method produces various silanols in a simple, cost-effective, efficient (92%–99% yields) and scalable fashion, its reaction mechanism is very different than the reported ones associated with metal catalysis.
Platinum Complexes with a Phosphino-Oxime/Oximate Ligand
Francos, Javier,Borge, Javier,Conejero, Salvador,Cadierno, Victorio
, p. 3176 - 3186 (2018/07/31)
The platinum(II) complex [PtCl2(COD)] (2; COD = 1,5-cyclooctadiene) reacted with 1 and 2 equiv. of 2-(diphenylphosphanyl)benzaldehyde oxime (1) to generate [PtCl2{κ2-(P,N)-2-Ph2PC6H4CH=NOH}] (3) and [Pt{κ2-(P,N)-2-Ph2PC6H4CH=NOH}2][Cl]2 (4), respectively. Deprotonation of the oxime hydroxyl group of 3 with Na2CO3 led to the selective formation of the dinuclear species (μ-O)-[PtCl{κ2-(P,N)-2-Ph2PC6H4CH=NO}]2 (5), while the related methylated derivative (μ-O)-[PtMe{κ2-(P,N)-2-Ph2PC6H4CH=NO}]2 (7) could be obtained from the direct reaction of [PtMe2(COD)] (6) with the phosphino-oxime ligand 1. In the case of 4, its treatment with Na2CO3 yielded complex [Pt({κ2-(P,N)-2-Ph2PC6H4CH=NO}2H)][Cl] (8), as a result of the deprotonation of only one of the OH groups of 4. On the other hand, contrary to what was observed with 6, no deprotonation of the oxime occurred in the reaction of [PtMe3I]4 (9) with 1, from which the mononuclear PtIV derivative fac-[PtIMe3{κ2-(P,N)-2-Ph2PC6H4CH=NOH}] (10) was isolated. The solid-state structures of compounds 3, 4, 7 and 10 were determined by X-ray crystallography. In addition, the potential of all the synthesized complexes as catalysts for the dehydrogenative coupling of hydrosilanes with alcohols is also briefly discussed.
Dehydrogenative Coupling of Hydrosilanes and Alcohols by Alkali Metal Catalysts for Facile Synthesis of Silyl Ethers
Harinath, Adimulam,Bhattacharjee, Jayeeta,Anga, Srinivas,Panda, Tarun K.
, p. 724 - 730 (2017/05/31)
Cross-dehydrogenative coupling (CDC) of hydrosilanes with hydroxyl groups, using alkali metal hexamethyldisilazide as a single-component catalyst for the formation of Si-O bonds under mild condition, is reported. The potassium salt [KN(SiMe3)2] is highly efficient and chemoselective for a wide range of functionalized alcohols (99% conversion) under solvent-free conditions. The CDC reaction of alcohols with silanes exhibits first-order kinetics with respect to both catalyst and substrate concentrations. The most plausible mechanism for this reaction suggests that the initial step most likely involves the formation of an alkoxide followed by the formation of metal hydride as active species.
Metal-Free Ammonium Iodide Catalyzed Oxidative Dehydrocoupling of Silanes with Alcohols
Yuan, Yan-Qin,Kumar, Pailla Santhosh,Guo, Sheng-Rong
supporting information, p. 1620 - 1623 (2017/08/11)
An ammonium iodide catalyzed direct oxidative coupling of silanes with alcohols to give various alkoxysilane derivatives was discovered. tert -Butyl hydroperoxide proved to be an efficient oxidant for this transformation. Attractive features of this protocol include its transition-metal-free nature and the mild reaction conditions.
