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Phosphine boran

Petra Vasko, Ili A Zulkifly, M Ángeles Fuentes, Zhenbo Mo, Jamie Hicks, Paul C J Kämer, 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 CD₂Cl₂ 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(C₆F₅)₂ Lewis acid component by -Bpin/-Bcat, and transfer of HB(C₆F₅)₂ to the phosphine Lewis base...
May 22, 2018: Chemistry: a European Journal
Matthew J Chalkley, Trevor J Del Castillo, Benjamin D Matson, Jonas C Peters
Substrate selectivity in reductive multi-electron/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 thermo-dynamically and kinetically competent. In this study, we investigate how the selectivity of a tris(phosphine)borane iron(I) catalyst, P3BFe+, for catalyzing the nitrogen reduction reaction (N2RR, N2-to-NH3 conversion) versus HER changes as a function of acid pKa. We find that there is a strong correlation between pKa and N2RR efficiency...
April 18, 2018: Journal of the American Chemical Society
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...
March 28, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
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
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
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
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
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
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
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
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...
October 12, 2017: Journal of Organic Chemistry
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
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.
August 30, 2017: Journal of Organic Chemistry
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
Micheal Gediga, Christoph M Feil, Simon H Schlindwein, Johannes Bender, Martin Nieger, Dietrich Gudat
A neutral N-heterocyclic phosphenium complex of manganese was synthesised by a metathesis approach and characterised by IR, NMR, and XRD studies. The short P-Mn distance suggests a substantial metal-ligand double bond character. Reaction with a hydride produced an anionic phosphine complex, which was also characterised by IR and NMR spectroscopy and, after anion exchange, a single-crystal XRD study. Protonation of the anion occurs at the metal to yield a neutral phosphine metal carbonyl hydride, which releases dihydrogen upon irradiation with UV light...
August 25, 2017: Chemistry: a European Journal
David A Janus, Christopher J Lieven, Megan E Crowe, Leonard A Levin
Phosphine-borane complexes are recently developed redox-active drugs that are neuroprotective in models of optic nerve injury and radioprotective in endothelial cells. However, a single dose of these compounds is short-lived, necessitating the development of sustained-release formulations of these novel molecules. We screened a library of biodegradable co- and non-block polyester polymer systems for release of incorporated phosphine-borane complexes to evaluate them as drug delivery systems for use in chronic disease...
June 9, 2017: Pharmaceutical Development and Technology
A Telleria, P W N M van Leeuwen, Z Freixa
Eight new ruthenium(ii) half-sandwich complexes containing azobenzene-appended pyridine (1), bipyridine (2-5) and phosphine (6 and 7) ligands have been synthesized and fully characterized. UV-vis spectroscopic studies showed that the trans-to-cis photoisomerization was strongly inhibited upon coordination to the metal centre in azopyridine-derived ligands 1 and 2, but it remained efficient in azobenzene-appended bipyridine (3-5) and phosphine (6 and 7) ligands. The complexes were tested as precatalysts for photo-controlled hydrogen generation by hydrolytic decomposition of ammonia-borane (AB)...
March 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Kevin Rousée, Xavier Pannecoucke, Annie-Claude Gaumont, Jean-François Lohier, Fabrice Morlet-Savary, Jacques Lalevée, Jean-Philippe Bouillon, Samuel Couve-Bonnaire, Sami Lakhdar
This work describes the first transition metal-free stereospecific synthesis of (E)-(1-fluoro-2-arylvinyl)phosphine boranes through the addition of diarylphosphine-boranes to gem-bromofluoroalkenes in the presence of a base at room temperature. The reaction proceeds well under very mild conditions and tolerates a variety of functionalities. Scope and limitations of the reaction are discussed. Mechanistic investigations have been undertaken and revealed that the reaction takes place through an SRN 1 mechanism...
February 7, 2017: Chemical Communications: Chem Comm
Giovanni Bistoni, Alexander A Auer, Frank Neese
The interaction of Lewis acids and bases in both classical Lewis adducts and frustrated Lewis pairs (FLPs) is investigated to elucidate the role that London dispersion plays in different situations. The analysis comprises 14 different adducts between tris(pentafluorophenyl)borane and a series of phosphines, carbenes, and amines with various substituents, differing in both steric and electronic properties. The domain-based local pair natural orbital coupled-cluster (DLPNO-CCSD(T)) method is used in conjunction with the recently introduced local energy decomposition (LED) analysis to obtain state-of-the-art dissociation energies and, at the same time, a clear-cut definition of the London dispersion component of the interaction, with the ultimate goal of aiding in the development of designing principles for acid/base pairs with well-defined bonding features and reactivity...
January 18, 2017: Chemistry: a European Journal
Merle Arrowsmith, Dominic Auerhammer, Rüdiger Bertermann, Holger Braunschweig, Gerhard Bringmann, Mehmet Ali Celik, Rian D Dewhurst, Maik Finze, Matthias Grüne, Michael Hailmann, Thomas Hertle, Ivo Krummenacher
Reduction of carbene-borane adduct [(cAAC)BBr2 (CN)] (cAAC=1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) cleanly yielded the tetra(cyanoborylene) species [(cAAC)B(CN)]4 presenting a 12-membered (BCN)4 ring. The analysis of the Kohn-Sham molecular orbitals showed significant borylene character of the B(I) atoms. [(cAAC)B(CN)]4 was found to reduce two equivalents of AgCN per boron center to yield [(cAAC)B(CN)3 ] and fragmented into two-coordinate boron(I) units upon reaction with IMeMe (1,3,4,5-tetramethylimidazol-2-ylidene) to yield the corresponding tricoordinate mixed cAAC-NHC cyanoborylene...
October 12, 2016: Angewandte Chemie
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