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Phosphine boran

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https://www.readbyqxmd.com/read/29938294/frustrated-lewis-pairs-in-ionic-liquids-and-molecular-solvents-a-neutron-scattering-and-nmr-study-of-encounter-complexes
#1
Lucy C Brown, James M Hogg, Mark Gilmore, Leila Moura, Silvia Imberti, Sabrina Gärtner, H Q Nimal Gunaratne, Ruairi J O'Donnell, Nancy Artioli, John D Holbrey, Małgorzata Swadźba-Kwaśny
The presence of the weakly-associated encounter complex in the model frustrated Lewis pair solution (FLP): tris(tert-butyl)phosphine (P(tBu)3) and tris(pentafluorophenyl)borane (BCF) in benzene, was confirmed via PB correlation analysis from neutron scattering data. On average, ca. 5% of dissolved FLP components were in the associated state. NMR spectra of the FLP in benzene gave no evidence of such association, in agreement with earlier reports and the transient nature of the encounter complex. In contrast, the corresponding FLP solution in the ionic liquid, 1-decyl-3-methylimidazolium bistriflamide, [C10mim][NTf2], generated NMR signals that can be attributed to formation of encounter complexes involving over 20% of the dissolved species...
June 25, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29927388/investigation-of-interactions-in-lewis-pairs-between-phosphines-and-boranes-by-analyzing-crystal-structures-from-the-cambridge-structural-database
#2
Milan R Milovanović, Jelena M Andrić, Vesna B Medaković, Jean Pierre Djukic, Sneǽana D Zarić
The interactions between phosphines and boranes in crystal structures have been investigated by analyzing data from the Cambridge Structural Database (CSD). The interactions between phosphines and boranes were classified into three types; two types depend on groups on the boron atom, whereas the third one involves frustrated Lewis pairs (FLPs). The data enabled geometric parameters in structures to be compared with phosphine-borane FLPs with classical Lewis pairs. Most of the crystal structures (78.1%) contain BH3 as the borane group...
June 1, 2018: Acta Crystallographica Section B, Structural Science, Crystal Engineering and Materials
https://www.readbyqxmd.com/read/29922796/interception-of-intermediates-in-phosphine-oxidation-by-mesityl-nitrile-n-oxide-using-frustrated-lewis-pairs
#3
Kevin M Szkop, Diya Zhu, Lauren E Longobardi, Julian Heck, Douglas W Stephan
Phosphine oxidation by MesCNO is rapid; however, an FLP strategy intercepts the 1,3 addition products including [MesC(R3P)NOB(C6F5)3] (R = Ph 1, p-tol 2), [MesC(Mes2PH)NOB(C6F5)3] 3 (MesC(NOB(C6F5)3)Ph2P)2(CH2)n (n = 2: 4, 3: 5) and [MesC(Ph3P)NOB(C6F4H)3] 6. These species are shown to react with tBuOK or [Bu4N]F permitting the oxidation to proceed via a process involving borane dissociation. Similarly, the equilibrium established by 1 with B(C6F4H)3 and 6 with B(C6F5)3 provides experimental support for the "Cummins mechanism" for these phosphine oxidations...
June 20, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29901244/polymer-meets-frustrated-lewis-pair-second-generation-co-2-responsive-nanosystem-for-sustainable-co-2-conversion
#4
Liang Chen, Renjie Liu, Qiang Yan
Frustrated Lewis pairs (FLP), a couple comprising a sterically encumbered Lewis acid and Lewis base, can offer latent reactivity for activating inert gas molecules. However, their use as a platform for fabricating gas-responsive materials has not yet developed. Merging the FLP concept with polymers, we report a new generation CO2 -responsive system, differing from the first-generation ones based on an acid-base equilibrium mechanism. Two complementary Lewis acidic and basic block copolymers, installing bulky borane- and phosphine-containing blocks, were built as the macromolecular FLP...
June 14, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29901042/access-to-a-pair-of-ambiphilic-phosphine-borane-regioisomers-by-rhodium-catalyzed-hydroboration
#5
Brian R Nichols, Novruz G Akhmedov, Jeffrey L Petersen, Brian V Popp
Lewis basic substrates, such as vinylphosphines and enamines, can be problematic for transition-metal catalysed hydrofunctionalization reactions due to their propensity to ligate and deactivate transition-metal catalysts as well as form direct Lewis adducts with reaction partners. While exploring rhodium-catalyzed hydroboration of diphenylvinylphosphine with pinacolborane, we found that a high degree of regiocontrol could be achieved without the need to diminish the Lewis basicity of the phosphine by oxidation or prior-protection...
June 25, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29882283/ring-opening-of-epoxides-mediated-by-frustrated-lewis-pairs
#6
Chris Slootweg, Tania Krachko, Emmanuel Nicolas, Andreas Ehlers, Martin Nieger
Treatment of the preorganized frustrated Lewis pairs (FLPs) tBu2PCH2BPh2 (1) and o-Ph2P(C6H4)BCat (Cat = catechol) (4) with 2-methyloxirane, 2-phenyloxirane and 2-(trifluoromethyl)oxirane resulted in epoxide ring-opening to yield the six- and seven-membered heterocycles 2a-c and 5a-c, respectively. These zwitterionic products were characterized spectroscopically, and compounds 2a, 2b, 5a and 5c were structurally characterized by single-crystal X-ray structure analyses. Based on computational and kinetic studies, the mechanism of these reactions was found to proceed via activation of the epoxide by the Lewis acidic borane moiety followed by nucleophilic attack of the phosphine of a second FLP molecule...
June 7, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29786906/reversible-c-h-activation-facile-c-b-b-h-metathesis-and-apparent-hydroboration-catalysis-by-a-dimethylxanthene-based-frustrated-lewis-pair
#7
Petra Vasko, Ili A Zulkifly, M Ángeles Fuentes, Zhenbo Mo, Jamie Hicks, Paul C J Kamer, Simon Aldridge
A dimethylxanthene-based phosphine/borane frustrated Lewis pair (FLP) is shown to effect reversible C-H activation, cleaving phenylacetylene, PhCCH, to give an equilibrium mixture of the free FLP and phosphonium acetylide in CD2 Cl2 solution at room temperature. This system also reacts with B-H bonds although in a different fashion: reactions with HBpin and HBcat proceed via C-B/B-H metathesis, leading to replacement of the -B(C6 F5 )2 Lewis acid component by -Bpin/-Bcat, and transfer of HB(C6 F5 )2 to the phosphine Lewis base...
May 22, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29669205/fe-mediated-nitrogen-fixation-with-a-metallocene-mediator-exploring-p-k-a-effects-and-demonstrating-electrocatalysis
#8
Matthew J Chalkley, Trevor J Del Castillo, Benjamin D Matson, Jonas C Peters
Substrate selectivity in reductive multielectron/proton catalysis with small molecules such as N2 , CO2 , and O2 is a major challenge for catalyst design, especially where the competing hydrogen evolution reaction (HER) is thermodynamically and kinetically competent. In this study, we investigate how the selectivity of a tris(phosphine)borane iron(I) catalyst, P3 B Fe+ , for catalyzing the nitrogen reduction reaction (N2 RR, N2 -to-NH3 conversion) versus HER changes as a function of acid p Ka . We find that there is a strong correlation between p Ka and N2 RR efficiency...
May 16, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29589633/synthesis-and-coordination-chemistry-of-enantiopure-t-bumep-o-h
#9
Albert Gallen, Sílvia Orgué, Guillermo Muller, Eduardo C Escudero-Adán, Antoni Riera, Xavier Verdaguer, Arnald Grabulosa
Both enantiomers of the optically pure Secondary Phosphine Oxide (SPO) t-BuMeP(O)H (1) have been obtained by deboronation of phosphinous acid-borane t-BuMeP(O)H·BH3 (3) with HBF4 followed by hydrolysis of the intermediate adduct t-BuMeP(O)H·BF3 (1·BF3), which has been isolated and crystallographically characterised. Complexes [MCl(COD)(κP-(R)-1)] (M = Ir, Rh; 4 and 7 respectively) have been detected in solution but could not be isolated while trans-[RhCl(CO)(κP-(S)-1)2] (9) has been successfully obtained in good yield...
April 17, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29533492/synthesis-and-identification-of-aryl-and-alkyl-gem-dilithium-phosphido-boranes-a-boost-to-the-chemistry-of-phosphandiides
#10
Jie Guang, Romain Duwald, Jacques Maddaluno, Hassan Oulyadi, Sami Lakhdar, Annie-Claude Gaumont, Anne Harrison-Marchand
The synthesis and identification of unprecedented gem-dianionic phosphorus compounds, that is, gem-dilithium phosphido-boranes Li2 [RP⋅BH3 ], with R=Ph or Cy, are reported in THF solution. These were obtained by double deprotonation of the corresponding primary phosphine-borane precursors RPH2 ⋅BH3 . Their in-depth structural study, based on multinuclear (1 H, 6 Li, 7 Li, 11 B, 13 C, 31 P) mono- and bi-dimensional NMR analyses, indicates a strong influence of the phosphorus substituent on the structure of the gem-dianionic phosphorus structure; a monomeric arrangement was obtained when R=phenyl, whereas a cyclic oligomer was observed for R=cyclohexyl...
May 7, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29504739/controllable-carrier-type-in-boron-phosphide-nanowires-toward-homostructural-optoelectronic-devices
#11
Nan Ding, Junqi Xu, Qi Zhang, Jianwei Su, Yu Gao, Xing Zhou, Tianyou Zhai
The p-n junction is one important and fundamental building block of the optoelectronic age. However, electrons and holes will be severely scattered in heterostructures led by the grain boundary at the alloy interface between two dissimilar semiconductors. In this work, we present boron phosphide (BP) nanowires with artificially controllable carrier type for the fabrication of homojunctions via adjusting borane/phosphine ratio during the deposition process, both prove high crystallization with fewer impurities...
March 28, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29497210/iron-catalyzed-dehydrocoupling-of-amine-and-phosphine-boranes
#12
REVIEW
Nathan T Coles, Ruth L Webster
Catalytic dehydrocoupling methodologies, whereby dihydrogen is released from a substrate (or intermolecularly from two substrates) is a mild and efficient method to construct main group element-main group element bonds, the products of which can be used in advanced materials, and also for the development of hydrogen storage materials. With growing interest in the potential of compounds such as ammonia-borane to act as hydrogen storage materials which contain a high weight% of H2 , along with the current heightened interest in base metal catalyzed processes, this review covers recent developments in amine and phosphine dehydrocoupling catalyzed by iron complexes...
December 2017: Israel Journal of Chemistry
https://www.readbyqxmd.com/read/29389052/umpolung-at-boron-ancillary-ligand-induced-formation-of-boron-based-donor-ligands-from-phosphine-boranes
#13
Lisa Vondung, Lukas Alig, Monika Ballmann, Robert Langer
Easy-to-prepare η2 -coordinated phosphine-borane ligands are demonstrated to liberate hydrogen upon treatment with different σ-donor/π-acceptor ligands (CO, tBuNC, CN- ). Depending on the utilized ancillary ligand, different reaction pathways are observed, ranging from simple hydride protonation to iron-boron bond formation and subsequent rearrangement to pincer-type ligands based on a tricoordinate boron centre. The last-named reactivity is in line with a formal umpolung at the boron centre from a Lewis acidic borane to a Lewis basic boron-based donor ligand...
February 1, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29243918/frustrated-lewis-pairs-catalyzed-asymmetric-metal-free-hydrogenations-and-hydrosilylations
#14
Wei Meng, Xiangqing Feng, Haifeng Du
The use of frustrated Lewis pairs is an extremely important approach to metal-free hydrogenations. In contrast to the rapid growth of catalytic reactions, asymmetric hydrogenations are far less developed due to a severe shortage of readily available chiral frustrated Lewis pair catalysts with high catalytic activities and selectivities. Unlike the stable Lewis base component of frustrated Lewis pairs, the moisture-sensitive boron Lewis acid component is difficult to prepare. The development of convenient methods for the quick construction of chiral boron Lewis acids is therefore of great interest...
January 16, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29181109/synthesis-and-photophysical-properties-of-novel-benzophospholo-3-2-b-indole-derivatives
#15
Mio Matsumura, Mizuki Yamada, Atsuya Muranaka, Misae Kanai, Naoki Kakusawa, Daisuke Hashizume, Masanobu Uchiyama, Shuji Yasuike
The parent benzophospholo[3,2- b ]indole was prepared by the reaction of dichlorophenylphosphine with a dilithium intermediate, which was prepared in two steps from 2-ethynyl- N , N -dimethylaniline. Using the obtained benzophosphole-fused indole as a common starting material, simple modifications were carried out at the phosphorus center of the phosphole, synthesizing various functionalized analogs. The X-ray structure analysis of trivalent phosphole and phosphine oxide showed that the fused tetracyclic moieties are planar...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29095634/direct-allylic-amination-of-allylic-alcohol-catalyzed-by-palladium-complex-bearing-phosphine-borane-ligand
#16
Goki Hirata, Hideaki Satomura, Hidenobu Kumagae, Aika Shimizu, Gen Onodera, Masanari Kimura
The direct electrophilic, nucleophilic, and amphiphilic allylations of allylic alcohol by use of a palladium catalyst and organometallic reagents such as organoborane and organozinc has been developed. The phosphine-borane compound works as the effective ligand for palladium-catalyzed direct allylic amination of allylic alcohol. Thus, with secondary amines, the reaction was completed in only 1 h, even at room temperature.
November 17, 2017: Organic Letters
https://www.readbyqxmd.com/read/28956926/-60-fullerene-l-amino-acids-and-peptides-synthesis-under-phase-transfer-catalysis-using-a-phosphine-borane-linker-electrochemical-behavior
#17
Pauline Minois, Jérôme Bayardon, Rita Meunier-Prest, Sylvain Jugé
A new method to link amino acid and peptide derivatives to [60]fullerene is described. It uses hydrophosphination with a secondary phosphine borane. First, the stereoselective synthesis of secondary phosphine borane amino acid derivatives was achieved by alkylation of phenylphosphine borane with γ-iodo-α-amino ester reagents under phase-transfer catalysis (PTC). Second, a sec-phosphine borane amino ester was saponified and coupled with α,γ-diamino esters to afford the corresponding dipeptide derivatives in good yields...
November 3, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28932423/crystal-structure-of-triphenylphosphonium-meth-yl-enetrifluoroborate
#18
Christopher M Bateman, Lev N Zakharov, Eric R Abbey
The title compound, C19H17BF3P {alternative name: triphen-yl[(tri-fluoro-boran-yl)meth-yl]phosphanium}, was formed by the reaction of tri-phenyl-phosphine with potassium iodo-methyl-tri-fluoro-borate. The mol-ecule features a nearly staggered conformation along the P-C bond and a less than staggered conformation along the C-B bond. In the crystal, weak C-H⋯F hydrogen bonds between the meta-phenyl C-H groups and the tri-fluoro-borate B-F groups form chains of R2(2)(16) rings along [100]. These chains are are further stabilized by weak C-H⋯π inter-actions...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28813606/nonepimerizing-alkylation-of-h-p-species-to-stereospecifically-generate-p-stereogenic-phosphine-oxides-a-shortcut-to-bidentate-tertiary-phosphine-ligands
#19
Shao-Zhen Nie, Zhong-Yang Zhou, Ji-Ping Wang, Hui Yan, Jing-Hong Wen, Jing-Jing Ye, Yun-Yao Cui, Chang-Qiu Zhao
The secondary RP -(-)-menthyl alkylphosphine oxide was confirmed as configurationally stable toward base and was used in base-promoted alkylation, stereospecifically affording P-retained bis or functional tertiary phosphine oxides in excellent yields. The alkylated products were deoxygenated using oxalyl chloride followed by ZnCl2 -NaBH4 to form P-inversed bidentate phosphine boranes in high stereoselectivities.
September 15, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28577325/borylenes-an-emerging-class-of-compounds
#20
REVIEW
Michele Soleilhavoup, Guy Bertrand
Free borylenes (R-B:) have only been spectroscopically characterized in the gas phase or in matrices at very low temperatures. However, in recent years, a few mono- and bis(Lewis base)-stabilized borylenes have been isolated. In both of these compounds the boron atom is in the formal oxidation state +I which contrasts with classical organoboron derivatives wherein the element is in the +III oxidation state. Mono(Lewis base)-stabilized borylenes are isoelectronic with singlet carbenes, and their reactivity mimics to some extent that of transition metals...
August 21, 2017: Angewandte Chemie
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