The Experts below are selected from a list of 471 Experts worldwide ranked by ideXlab platform
Do T Tilley - One of the best experts on this subject based on the ideXlab platform.
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lewis acidity of bis perfluorocatecholato silane aldehyde hydrosilylation catalyzed by a neutral silicon compound
Journal of the American Chemical Society, 2015Co-Authors: Allegra L Libermanmarti, Robe G Ergma, Do T TilleyAbstract:Bis(perfluorocatecholato)silane Si(catF)2 was prepared, and stoichiometric binding to Lewis bases was demonstrated with fluoride, Triethylphosphine oxide, and N,N′-diisopropylbenzamide. The potent Lewis acidity of Si(catF)2 was suggested from catalytic hydrosilylation and silylcyanation reactions with aldehydes. Mechanistic studies of hydrosilylation using an optically active silane substrate, R-(+)-methyl-(1-naphthyl)phenylsilane, proceeded with predominant stereochemical retention at silicon, consistent with a carbonyl activation pathway. The enantiospecificity was dependent on solvent and salt effects, with increasing solvent polarity or addition of NBu4BArF4 leading to a diminished enantiomeric ratio. The medium effects are consistent with an ionic mechanism, wherein hydride transfer occurs prior to silicon–oxygen bond formation.
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Lewis Acidity of Bis(perfluorocatecholato)silane: Aldehyde Hydrosilylation Catalyzed by a Neutral Silicon Compound
2015Co-Authors: Allegra L. Liberman-martin, Robert G. Bergman, Do T TilleyAbstract:Bis(perfluorocatecholato)silane Si(catF)2 was prepared, and stoichiometric binding to Lewis bases was demonstrated with fluoride, Triethylphosphine oxide, and N,N′-diisopropylbenzamide. The potent Lewis acidity of Si(catF)2 was suggested from catalytic hydrosilylation and silylcyanation reactions with aldehydes. Mechanistic studies of hydrosilylation using an optically active silane substrate, R-(+)-methyl-(1-naphthyl)phenylsilane, proceeded with predominant stereochemical retention at silicon, consistent with a carbonyl activation pathway. The enantiospecificity was dependent on solvent and salt effects, with increasing solvent polarity or addition of NBu4BArF4 leading to a diminished enantiomeric ratio. The medium effects are consistent with an ionic mechanism, wherein hydride transfer occurs prior to silicon–oxygen bond formation
Nour-eddine Aouf - One of the best experts on this subject based on the ideXlab platform.
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a greener procedure for the synthesis of α ureidophosphonates under ultrasound irradiation an x ray crystallographic study
RSC Advances, 2015Co-Authors: Abdeslem Bouzina, Malika Berredjem, Sofiane Bouacida, Hocine Merazig, Nour-eddine AoufAbstract:An efficient, eco-sustainable and greener procedure for the synthesis of α-ureidophosphonates via a one-pot three-component reaction of aldehydes, urea/thiourea and triethylphosphite or diethylphosphite using ultrasonic irradiation under solvent- and catalyst-free conditions at 75°, is developed. The desired products were obtained in excellent yields within short reaction times (15–30 min). Crystals of diethyl[α-ureido-(4-methylphenyl)]methyl phosphonate suitable for X-ray study have been obtained after recrystallization in a mixture of diethyl ether and n-hexane. The detailed analysis of the molecular and crystal structure is presented.
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a novel rapid and green method of phosphorylation under ultrasound irradiation and catalyst free conditions
RSC Advances, 2015Co-Authors: Abdeslem Bouzina, Nour-eddine Aouf, Billel Belhani, Malika BerredjemAbstract:The phosphorylation reaction of various N-acylamines, N-acylaminoesters N-acylaminoalcohols and N-acylsulfonamides with trimethylphosphite or triethylphosphite was effectively promoted under ultrasound irradiation, solvent and catalyst free conditions to produce the corresponding amidophosponate. This rapid method produced the products in short reaction times (5–15 min) and excellent yields (75–90%). This technique at a frequency of 40 kHz, strongly accelerates the process of formation of P–C bonds compared to the classic Arbuzov reaction.
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a one pot three component synthesis of novel α sulfamidophosphonates under ultrasound irradiation and catalyst free conditions
RSC Advances, 2015Co-Authors: Billel Belhani, Malika Berredjem, Marc Le Borgne, Zouhair Bouaziz, Jacques Lebreton, Nour-eddine AoufAbstract:An efficient and convenient one-pot synthesis of novel α-sulfamidophosphonates is described via a three-component reaction. This reaction was carried out through a three component condensation reaction of sulfonamide, an aromatic aldehyde and triethylphosphite under conventional/ultrasonic techniques, catalyst-free and solvent-free conditions. This methodology was established with many advantages, including mild reaction conditions, short reaction times, good yields, simple work-up procedures, and environmental friendliness.
Wei Jun Jin - One of the best experts on this subject based on the ideXlab platform.
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the competition of c x o p halogen bond and π hole o p bond between halopentafluorobenzenes c 6 f 5 x x f cl br i and Triethylphosphine oxide
Journal of Molecular Modeling, 2013Co-Authors: Xiao Ran Zhao, Hui Wang, Wei Jun JinAbstract:Calculation predicted the interacting forms of halopentafluorobenzene C6F5X (X=F, Cl, Br, I) with Triethylphosphine oxide which is biologically interested and easily detected by 31P NMR. The interaction energy and geometric parameters of resultant halogen or π-hole bonding complexes were estimated and compared. Moreover, the bonding constants were determined by 31P NMR. Both theory and experiments indicated the C6F6 and C6F5Cl interact with Triethylphosphine oxide by π-hole bonding pattern, while C6F5I by halogen/σ-hole bonding form. For C6F5Br, two interactions are comparative and should coexist competitively. The calculated interaction energies of σ-hole bonding complexes, −5.07 kcal mol−1 for C6F5Br⋯O=P and −8.25 kcal mol−1 for C6F5I⋯O=P, and π-hole bonding complexes, −7.29 kcal mol−1 for C6F6⋯O=P and −7.24 kcal mol−1 for C6F5Cl⋯O=P, are consistent with the changing tendency of bonding constants measured by 31P NMR, 4.37, 19.7, 2.42 and 2.23 M−1, respectively.
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acceptor number of halogenated solvents and its potential as a criterion for the ability of halogen bonding as a specific solvent effect using the 31p nmr chemical shift of Triethylphosphine oxide as a probe
Chemical Physics Letters, 2013Co-Authors: Xiao Ran Zhao, Qian Jin Shen, Wei Jun JinAbstract:Abstract Acceptor numbers ( AN ) of several halogenated and perfluorohalogenated solvents were determined using 31 P NMR of Triethylphosphine oxide (Et 3 P O) as a probe. The halogen and/or hydrogen bonding complex, C–X⋯O PEt 3 or C–H⋯O PEt 3 , between the probe and solvent molecules was simulated by MP2 and DFT methods. The halogen bonding energies of perfluorohalogenated solvents and iodobenzene with the probe show a good linear correlation to the AN . The results indicate that the AN can act as a possible criterion for the ability of halogen bonding as a specific solvent effect.
Allegra L Libermanmarti - One of the best experts on this subject based on the ideXlab platform.
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lewis acidity of bis perfluorocatecholato silane aldehyde hydrosilylation catalyzed by a neutral silicon compound
Journal of the American Chemical Society, 2015Co-Authors: Allegra L Libermanmarti, Robe G Ergma, Do T TilleyAbstract:Bis(perfluorocatecholato)silane Si(catF)2 was prepared, and stoichiometric binding to Lewis bases was demonstrated with fluoride, Triethylphosphine oxide, and N,N′-diisopropylbenzamide. The potent Lewis acidity of Si(catF)2 was suggested from catalytic hydrosilylation and silylcyanation reactions with aldehydes. Mechanistic studies of hydrosilylation using an optically active silane substrate, R-(+)-methyl-(1-naphthyl)phenylsilane, proceeded with predominant stereochemical retention at silicon, consistent with a carbonyl activation pathway. The enantiospecificity was dependent on solvent and salt effects, with increasing solvent polarity or addition of NBu4BArF4 leading to a diminished enantiomeric ratio. The medium effects are consistent with an ionic mechanism, wherein hydride transfer occurs prior to silicon–oxygen bond formation.
Malika Berredjem - One of the best experts on this subject based on the ideXlab platform.
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a greener procedure for the synthesis of α ureidophosphonates under ultrasound irradiation an x ray crystallographic study
RSC Advances, 2015Co-Authors: Abdeslem Bouzina, Malika Berredjem, Sofiane Bouacida, Hocine Merazig, Nour-eddine AoufAbstract:An efficient, eco-sustainable and greener procedure for the synthesis of α-ureidophosphonates via a one-pot three-component reaction of aldehydes, urea/thiourea and triethylphosphite or diethylphosphite using ultrasonic irradiation under solvent- and catalyst-free conditions at 75°, is developed. The desired products were obtained in excellent yields within short reaction times (15–30 min). Crystals of diethyl[α-ureido-(4-methylphenyl)]methyl phosphonate suitable for X-ray study have been obtained after recrystallization in a mixture of diethyl ether and n-hexane. The detailed analysis of the molecular and crystal structure is presented.
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a novel rapid and green method of phosphorylation under ultrasound irradiation and catalyst free conditions
RSC Advances, 2015Co-Authors: Abdeslem Bouzina, Nour-eddine Aouf, Billel Belhani, Malika BerredjemAbstract:The phosphorylation reaction of various N-acylamines, N-acylaminoesters N-acylaminoalcohols and N-acylsulfonamides with trimethylphosphite or triethylphosphite was effectively promoted under ultrasound irradiation, solvent and catalyst free conditions to produce the corresponding amidophosponate. This rapid method produced the products in short reaction times (5–15 min) and excellent yields (75–90%). This technique at a frequency of 40 kHz, strongly accelerates the process of formation of P–C bonds compared to the classic Arbuzov reaction.
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a one pot three component synthesis of novel α sulfamidophosphonates under ultrasound irradiation and catalyst free conditions
RSC Advances, 2015Co-Authors: Billel Belhani, Malika Berredjem, Marc Le Borgne, Zouhair Bouaziz, Jacques Lebreton, Nour-eddine AoufAbstract:An efficient and convenient one-pot synthesis of novel α-sulfamidophosphonates is described via a three-component reaction. This reaction was carried out through a three component condensation reaction of sulfonamide, an aromatic aldehyde and triethylphosphite under conventional/ultrasonic techniques, catalyst-free and solvent-free conditions. This methodology was established with many advantages, including mild reaction conditions, short reaction times, good yields, simple work-up procedures, and environmental friendliness.
