The Experts below are selected from a list of 10314 Experts worldwide ranked by ideXlab platform
Ryo Shintani - One of the best experts on this subject based on the ideXlab platform.
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recent advances in the transition metal catalyzed enantioselective synthesis of silicon stereogenic Organosilanes
Asian Journal of Organic Chemistry, 2015Co-Authors: Ryo ShintaniAbstract:Asymmetric catalysis is one of the most attractive and efficient ways of synthesizing chiral enantioenriched compounds from achiral precursors. Compared with the well-investigated enantioselective preparation of carbon-stereogenic compounds, the corresponding preparation of silicon-stereogenic compounds is much less established. In particular, the available methods typically rely on the use of stoichiometric amounts of chiral reagents, and little progress has been made on catalytic enantioselective synthesis using prochiral Organosilanes until recently. This Focus Review highlights recent advances in the catalytic enantioselective preparation of silicon-stereogenic Organosilanes under transition-metal catalysis through desymmetrization of prochiral Organosilanes including diorganodihydrosilanes and tetraOrganosilanes.
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Recent Advances in the Transition‐Metal‐Catalyzed Enantioselective Synthesis of Silicon‐Stereogenic Organosilanes
Asian Journal of Organic Chemistry, 2015Co-Authors: Ryo ShintaniAbstract:Asymmetric catalysis is one of the most attractive and efficient ways of synthesizing chiral enantioenriched compounds from achiral precursors. Compared with the well-investigated enantioselective preparation of carbon-stereogenic compounds, the corresponding preparation of silicon-stereogenic compounds is much less established. In particular, the available methods typically rely on the use of stoichiometric amounts of chiral reagents, and little progress has been made on catalytic enantioselective synthesis using prochiral Organosilanes until recently. This Focus Review highlights recent advances in the catalytic enantioselective preparation of silicon-stereogenic Organosilanes under transition-metal catalysis through desymmetrization of prochiral Organosilanes including diorganodihydrosilanes and tetraOrganosilanes.
Weikang Yuan - One of the best experts on this subject based on the ideXlab platform.
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synthesis of hierarchically porous zsm 5 zeolites by steam assisted crystallization of dry gels silanized with short chain Organosilanes
New Journal of Chemistry, 2014Co-Authors: Yicheng Zhang, Kake Zhu, Xinggui Zhou, Weikang YuanAbstract:Three short-chain Organosilanes, i.e., 3-aminopropyltrimethoxy-silane (APTMS), [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEAPTMS) and phenylaminopropyltrimethoxysilane (PHAPTMS), were used for the synthesis of hierarchically micro-/mesoporous ZSM-5 zeolites by steam-assisted crystallization of silanized dry gels. Corresponding to the different moieties of Organosilanes, the obtained hierarchically porous ZSM-5 zeolites have different degrees of mesoporosity and exhibit spherical morphology composed of small nanounits. Among the three Organosilanes, PHAPTMS with a bulky cross-section is the most excellent mesopore directing agent. Tracking the structural evolution of PHAPTMS-ZSM-5 during crystallization shows that a large number of mesopores are produced in the initial steaming, but it is confirmed that it does not occur due to the presence of PHAPTMS. This initial mesoporosity is mostly preserved by the PHAPTMS molecules which inhibit the growth of the crystalline phase and suppress the high mobility of aluminosilicate species under the steam atmosphere.
Jayne C. Garno - One of the best experts on this subject based on the ideXlab platform.
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Surface-directed synthesis of erbium-doped yttrium oxide nanoparticles within organosilane zeptoliter containers.
ACS applied materials & interfaces, 2014Co-Authors: Lauren E. Englade-franklin, Gregory Morrison, Susan D. Verberne-sutton, Asenath L. Francis, Julia Y. Chan, Jayne C. GarnoAbstract:We introduce an approach to synthesize rare earth oxide nanoparticles using high temperature without aggregation of the nanoparticles. The dispersity of the nanoparticles is controlled at the nanoscale by using small organosilane molds as reaction containers. Zeptoliter reaction vessels prepared from organosilane self-assembled monolayers (SAMs) were used for the surface-directed synthesis of rare earth oxide (REO) nanoparticles. Nanopores of octadecyltrichlorosilane were prepared on Si(111) using particle lithography with immersion steps. The nanopores were filled with a precursor solution of erbium and yttrium salts to confine the crystallization step to occur within individual zeptoliter-sized organosilane reaction vessels. Areas between the nanopores were separated by a matrix film of octadecyltrichlorosilane. With heating, the organosilane template was removed by calcination to generate a surface array of erbium-doped yttria nanoparticles. Nanoparticles synthesized by the surface-directed approach re...
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Nanostructures of functionalized gold nanoparticles prepared by particle lithography with Organosilanes.
Langmuir : the ACS journal of surfaces and colloids, 2011Co-Authors: Kathie L. Lusker, Jayne C. GarnoAbstract:Periodic arrays of organosilane nanostructures were prepared with particle lithography to define sites for selective adsorption of functionalized gold nanoparticles. Essentially, the approach for nanoparticle lithography consists of procedures with two masks. First, latex mesospheres were used as a surface mask for deposition of an organosilane vapor, to produce an array of holes within a covalently bonded, organic thin film. The latex particles were readily removed with solvent rinses to expose discrete patterns of nanosized holes of uncovered substrate. The nanostructured film of Organosilanes was then used as a surface mask for a second patterning step, with immersion in a solution of functionalized nanoparticles. Patterned substrates were fully submerged in a solution of surface-active gold nanoparticles coated with 3-mercaptopropyltrimethoxysilane. Regularly shaped, nanoscopic areas of bare substrate produced by removal of the latex mask provided sites to bind silanol-terminated gold nanoparticles, a...
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Particle lithography with vapor deposition of Organosilanes: A molecular toolkit for studying confined surface reactions in nanoscale liquid volumes
Thin Solid Films, 2011Co-Authors: Kathie L. Lusker, Jayne C. GarnoAbstract:Combining particle lithography with molecular self-assembly provides a practical approach for producing 2D arrays of organosilane nanostructures with well-defined geometries and designated surface coverage. By combining heated chemical vapor deposition with particle lithography, the binding of Organosilanes on substrates is narrowly confined to the locations of water residues surrounding the base of latex spheres. Localized meniscus sites of water designate specific locations for the hydrolysis and condensation reactions of Organosilanes. With particle lithography, billions of regular nanopatterns can be generated with high throughput to provide exquisite nanoscale control of the geometry, density and surface coverage of organosilane nanostructures. In this report, examples of organosilane nanopatterns presenting different terminal groups and chain lengths are demonstrated with atomic force microscopy images. The effect of the terminal moieties of Organosilanes was investigated for nanostructures prepared by particle lithography by evaluating parameters of the number density, surface coverage and thickness of layers formed.
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engineering the spatial selectivity of surfaces at the nanoscale using particle lithography combined with vapor deposition of Organosilanes
ACS Nano, 2009Co-Authors: Kathie L. Lusker, Jayne C. GarnoAbstract:Particle lithography is a practical approach to generate millions of organosilane nanostructures on various surfaces, without the need for vacuum environments or expensive instrumentation. This report describes a stepwise chemistry route to prepare organosilane nanostructures and then apply the patterns as a spatially selective foundation to attach gold nanoparticles. Sites with thiol terminal groups were sufficiently small to localize the attachment of clusters of 2−5 nanoparticles. Basic steps such as centrifuging, drying, heating, and rinsing were used to generate arrays of regular nanopatterns. Close-packed films of monodisperse latex spheres can be used as an evaporative mask to spatially direct the placement of nanoscopic amounts of water on surfaces. Vapor phase Organosilanes deposit selectively at areas of the surface containing water residues to generate nanostructures with regular thickness, geometry, and periodicity as revealed in atomic force microscopy images. The area of contact underneath t...
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Elucidating the Role of Surface Hydrolysis in Preparing Organosilane Nanostructures via Particle Lithography
Nano letters, 2008Co-Authors: Jayne C. GarnoAbstract:A new method of particle lithography is described for preparing rings or nanoporous films of Organosilanes. Millions of exquisitely uniform and precisely spaced nanostructures with designed surface chemistry can be rapidly produced using vapor deposition through mesoparticle masks. Nanoscopic amounts of water are essential for initiating surface hydrosilation. Thus, the key step for preparing covalently bonded nanostructures of Organosilanes is to control drying parameters to spatially direct the placement of water on surfaces.
Yicheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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synthesis of hierarchically porous zsm 5 zeolites by steam assisted crystallization of dry gels silanized with short chain Organosilanes
New Journal of Chemistry, 2014Co-Authors: Yicheng Zhang, Kake Zhu, Xinggui Zhou, Weikang YuanAbstract:Three short-chain Organosilanes, i.e., 3-aminopropyltrimethoxy-silane (APTMS), [3-(2-aminoethyl)aminopropyl]trimethoxysilane (AEAPTMS) and phenylaminopropyltrimethoxysilane (PHAPTMS), were used for the synthesis of hierarchically micro-/mesoporous ZSM-5 zeolites by steam-assisted crystallization of silanized dry gels. Corresponding to the different moieties of Organosilanes, the obtained hierarchically porous ZSM-5 zeolites have different degrees of mesoporosity and exhibit spherical morphology composed of small nanounits. Among the three Organosilanes, PHAPTMS with a bulky cross-section is the most excellent mesopore directing agent. Tracking the structural evolution of PHAPTMS-ZSM-5 during crystallization shows that a large number of mesopores are produced in the initial steaming, but it is confirmed that it does not occur due to the presence of PHAPTMS. This initial mesoporosity is mostly preserved by the PHAPTMS molecules which inhibit the growth of the crystalline phase and suppress the high mobility of aluminosilicate species under the steam atmosphere.
Wenbo Liu - One of the best experts on this subject based on the ideXlab platform.
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iron catalyzed highly enantioselective hydrosilylation of unactivated terminal alkenes
Journal of the American Chemical Society, 2018Co-Authors: Biao Cheng, Wenbo LiuAbstract:The iron-catalyzed highly Markovnikov-type selective and enantioselective hydrosilylation of terminal aliphatic alkenes with good functional group tolerance is developed. This operationally simple protocol uses earth-abundant transition metal catalyst, readily available aliphatic alkenes and hydrosilanes to construct valuable chiral Organosilanes with better than 99% ee in most cases. The chiral aliphatic alkan-2-ol and chiral dihydroxysilane as an analogue of ketone could be efficiently synthesized via further derivatization of chiral Organosilanes without any racemization.
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Iron-Catalyzed Highly Enantioselective Hydrosilylation of Unactivated Terminal Alkenes
2018Co-Authors: Biao Cheng, Wenbo LiuAbstract:The iron-catalyzed highly Markovnikov-type selective and enantioselective hydrosilylation of terminal aliphatic alkenes with good functional group tolerance is developed. This operationally simple protocol uses earth-abundant transition metal catalyst, readily available aliphatic alkenes and hydrosilanes to construct valuable chiral Organosilanes with better than 99% ee in most cases. The chiral aliphatic alkan-2-ol and chiral dihydroxysilane as an analogue of ketone could be efficiently synthesized via further derivatization of chiral Organosilanes without any racemization
