- Photoinduced Dearomatizing Three-Component Coupling of Arylphosphines, Alkenes, and Water
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A unique photoinduced reaction that couples a triarylphosphine, an alkene, and water to produce 2-(cyclohexa-2,5-dienyl)ethylphosphine oxide is reported herein. The alkene inserts into a C(aryl)?P bond of the arylphosphine, the aryl ring is dearomatized into the cyclohexadienyl ring, and the phosphorus is oxidized. The three components are all readily available, and their intermolecular coupling significantly increases molecular complexity. The products formed are applicable to the Wittig olefination.
- Masuda, Yusuke,Tsuda, Hiromu,Murakami, Masahiro
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- The Trityl-Cation Mediated Phosphine Oxides Reduction
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Reduction of phosphine oxides into the corresponding phosphines using PhSiH3 as a reducing agent and Ph3C+[B(C6F5)4]? as an initiator is described. The process is highly efficient, reducing a broad range of secondary and tertiary alkyl and arylphosphines, bearing various functional groups in generally good yields. The reaction is believed to proceed through the generation of a silyl cation, which reaction with the phosphine oxide provides a phosphonium salt, further reduced by the silane to afford the desired phosphine along with siloxanes. (Figure presented.).
- Landais, Yannick,Laye, Claire,Lusseau, Jonathan,Robert, Frédéric
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supporting information
p. 3035 - 3043
(2021/05/10)
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- Self-assembly of Amphiphilic Porphyrins To Construct Nanoparticles for Highly Efficient Photodynamic Therapy
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Hydrophobic photosensitizers greatly affect cell permeability and enrichment in tumors, but they cannot be used directly for clinical applications because they always aggregate in water, preventing their circulation in the blood and accumulation in tumor
- Jiang, Meiyu,Wu, Jiasheng,Liu, Weimin,Ren, Haohui,Zhang, Wenjun,Lee, Chun-Sing,Wang, Pengfei
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p. 11195 - 11204
(2021/06/01)
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- Microwave assisted P–C coupling reactions without directly added P-ligands
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Our group introduced a green protocol for the Pd(OAc)2- or NiCl2-catalyzed P–C coupling reaction of aryl halides and various > P(O)H-compounds under MW conditions without directly added P-ligands. The reactivity of a few aryl derivatives in the Pd(OAc)2-catalyzed Hirao reaction was also studied. An induction period was observed in the reaction of bromobenzene and diphenylphosphine oxide. Finally, the less known copper(I)-promoted P–C coupling reactions were investigated experimentally. The mechanism was explored by quantum chemical calculations.
- Henyecz, Réka,Huszár, Bianka,Keglevich, Gy?rgy,Mucsi, Zoltán
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- Synthesis of Azaylide-Based Amphiphiles by the Staudinger Reaction
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Catalyst- and reagent-free reactions are powerful tools creating various functional molecules and materials. However, such chemical bonds are usually hydrolysable or require specific functional groups, which limits their use in aqueous media. Herein, we report the development of new amphiphiles through the Staudinger reaction. Simple mixing of chlorinated aryl azide with a hydrophilic moiety and various triarylphosphines (PAr3) gave rise to azaylide-based amphiphiles NPAr3, rapidly and quantitatively. The obtained NPAr3 formed ca. 2 nm-sized spherical aggregates (NPAr3)n in water. The hydrolysis of NPAr3 was significantly suppressed as compared with those of non-chlorinated amphiphiles nNPAr3. Computational studies revealed that the stability is mainly governed by the decrease in LUMO around the phosphorus atom owing to the o-substituted halogen groups. Furthermore, hydrophobic dyes such as Nile red and BODIPY were encapsulated by the spherical aggregates (NPAr3)n in water.
- Kishida, Natsuki,Suzuki, Hayate,Toyota, Shinji,Yamashina, Masahiro,Yoshizawa, Michito
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supporting information
p. 17915 - 17919
(2021/07/09)
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- Molecular Vises for Precisely Positioning Ligands near Catalytic Metal Centers in Metal-Organic Frameworks
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We report the construction of a molecular vise by pairing a tritopic phenylphosphorus(III) linker and a monotopic linker in opposite positions within a metal-organic framework. The angle between these linkers at metal sites is fixed upon changing the functionality in the monotopic linker, while the distance between them is precisely tuned. This distance within the molecular vise is accurately measured by 1H-31P solid-state nuclear magnetic resonance spectroscopy. This unveils the impact of the distance on catalytic performance without interference from electrostatic effects or changes in the angle of the ligand, which is unprecedented in classic organometallic complexes.
- Yan, Wei,Li, Shenhui,Yang, Tao,Xia, Yucong,Zhang, Xinrui,Wang, Chao,Yan, Zier,Deng, Feng,Zhou, Qianghui,Deng, Hexiang
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supporting information
p. 16182 - 16187
(2020/10/26)
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- Preparation method of high-reproducibility tris(4-carboxybiphenyl)phosphine
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The invention relates to the technical field of organic methodology, and relates to a preparation method of high-reproducibility tris(4-carboxybiphenyl)phosphine. The preparation method comprises thefollowing steps: reacting a hydroxyl-substituted phosphorus precursor with p-toluenesulfonyl chloride to form a compound, and carrying out a Suzuki coupling reaction on the compound to obtain anmethylester compound of a pentavalent phosphorus ligand; and carrying out chlorosilane reduction and hydrolysis to obtain the high-purity tris(4-carboxylbiphenyl)phosphine. The preparation method of tris(4-carboxyl biphenyl)phosphine has high reproducibility, and avoids using of butyl lithium and other high-risk organic reagents to synthesize brominated precursors. The preparation method of tris(4-carboxyl biphenyl)phosphine is high in yield and suitable for large-scale production.
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Paragraph 0024; 0032; 0034
(2020/11/23)
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- Air-stable phosphine organocatalysts for the hydroarsination reaction
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Readily-available triarylphosphines are explored as organocatalysts for the hydroarsination reaction. When compared to transition metal catalysis, phosphine organocatalysis greatly improved solvent compatibility of the hydroarsination of nitrostyrenes. Upon complete conversion, arsine products were isolated in up to 99% yield while up to 48% of the phosphine catalyst was still active. A mechanism was proposed and structure-activity analysis regarding catalyst activity concluded that sterically-bulkier catalysts were effective at minimizing catalyst deactivation.
- Leung, Pak-Hing,Li, Yongxin,Pullarkat, Sumod A.,Tay, Wee Shan,Yang, Xiang-Yuan
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supporting information
(2020/03/18)
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- Organic long afterglow material with photoactivation characteristic as well as preparation method and application thereof
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The invention discloses an organic long afterglow material with photoactivation characteristic, and a preparation method and application thereof. The chemical structure of the material has a general formula; and R in the formula is H, F, OCH3. According to the invention, the series of compounds are prepared by taking a triphenylphosphine oxide derivative as a research object and connecting different substituents to three benzene ring para-positions of triphenylphosphine oxide. after controlling of the ultraviolet irradiation time, the phosphorescence service life and the intensity of the series of materials are obviously improved. And in combination with different dynamic adjustability, multiple information encryption applications are realized.
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Paragraph 0056-0059
(2020/09/09)
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- Molecular tweezers based on trivalent phosphine, preparation method of molecular tweezers, metal-molecular tweezers catalyst, and preparation method and application of metal-molecular tweezers catalyst
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The invention relates to the technical field of inorganic-metal organic crossing and relates to the technical field of molecular tweezers, in particular to molecular tweezers based on trivalent phosphine, a preparation method of the molecular tweezers, a metal-molecular tweezer catalyst, a preparation method of the metal-molecular tweezer catalyst and an application of the metal-molecular tweezercatalyst, the molecular tweezer based on trivalent phosphine is named as P-MV-PCN-521-R, and R is any one of benzoic acid, p-nitrobenzoic acid, formic acid, p-methylbenzoic acid and dichloroacetic acid. The molecular tweezers based on the trivalent phosphine have distance adjustability. The trivalent phosphine-based metal-molecular tweezer catalyst provided by the invention has a high crystallinesurface area and a high specific surface area. The trivalent phosphine-based metal-molecular tweezer catalyst has good chemical stability and thermal stability, and is a primary condition for applyingthe trivalent phosphine-based metal-molecular tweezer catalyst to the actual field. The trivalent phosphine-based metal-molecular tweezer catalyst with adjustable distance provided by the invention has good selectivity for bromination of aromatic compounds.
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Paragraph 0033; 0041-0042
(2020/12/14)
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- Photooxidation of triarylphosphines under aerobic conditions in the presence of a gold(iii) complex on cellulose extracted from Carthamus tinctorius immobilized on nanofibrous phosphosilicate
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Triarylphosphines were converted to the corresponding oxides via photooxidation as a novel method. In this study, cellulose was extracted from the Carthamus tinctorius plant and then oxidized by sodium metaperiodate. A gold complex was supported on this natural cellulose. Then, a gold complex on natural cellulose supported on FPS (FPS/Au(iii)) was synthesized for the reduction of phosphine oxides to corresponding phosphines with remarkable chemoselectivity. The morphology of FPS led to higher catalytic activity. FPS/Au(iii) NPs were thoroughly characterized using TEM, FESEM, FTIR, TGA, and BET.
- Sadeghzadeh, Seyed Mohsen,Zhiani, Rahele
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p. 1509 - 1516
(2019/01/24)
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- Multifunctional crosslinking agent, crosslinked polymer, and method of making same
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A multifunctional crosslinking agent, a crosslinked polymer, and a method of making the same are disclosed. The multifunctional crosslinking agent, which may be used to crosslink amine-terminated polyamides, polyimides, or poly(amide-imide)s, includes thr
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Page/Page column 15
(2019/06/27)
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- Synthesis of novel thioxanthone-containing macromolecular photosensitizer and its photocatalytic property
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Aiming to overcome the disadvantages of small molecule photosensitizers, a novel macromolecular photosensitizer was designed and synthesized in this work. Firstly, the functional small molecule photosensitizer 9-oxo-9H-thioxanthene-2-carboxylic acid (TX-C
- Ding, Aishun,Chen, Yang,Wang, Guowei,Zhang, Yaopeng,Hu, Jianhua,Guo, Hao
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p. 101 - 108
(2019/05/16)
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- Visible light-induced 4-phenylthioxanthone-catalyzed aerobic oxidation of triarylphosphines
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We report herein a visible light-induced oxidation of triarylphosphines under aerobic condition with excellent functional group tolerance. In this transformation, the photo catalyst 4-phenylthioxanthone acted as a photosensitizer for the in situ generation of singlet oxygen. This new approach provided a cheaper and greener method for the preparation of phosphine oxide, showing great advantages in environmental protocols.
- Ding, Aishun,Li, Shijie,Chen, Yang,Jin, Ruiwen,Ye, Cong,Hu, Jianhua,Guo, Hao
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supporting information
p. 3880 - 3883
(2018/09/27)
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- Lewis-Base-Catalyzed Reductive Aldol Reaction to Access Quaternary Carbons
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A synthetic method for the efficient construction of β-hydroxylactones and lactams bearing α-quaternary carbon centers is described. This transformation relies on an electronically differentiated Lewis base catalyst, which is uniquely capable of promoting
- Deporre, Yvonne C.,Annand, James R.,Bar, Sukanta,Schindler, Corinna S.
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supporting information
p. 2580 - 2584
(2018/05/22)
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- Phosphine Oxidation with Water and Ferrocenium(III) Cation Induced by Visible-Light Irradiation
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Stoichiometric oxidation of phosphines with water and ferrocenium(III) cation as the oxygen atom source and the oxidizing reagent, respectively, was achieved in acetonitrile under visible-light irradiation by using 2,6-lutidine as the proton acceptor. The reaction required light irradiation, under which fluorescence was observed for the acetonitrile solution of the ferrocenium(III) cation.
- Tanabe, Yoshiaki,Nakajima, Kazunari,Nishibayashi, Yoshiaki
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supporting information
p. 18618 - 18622
(2018/11/30)
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- Eosin Y-catalyzed photooxidation of triarylphosphines under visible light irradiation and aerobic conditions
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We report herein a novel method for Eosin Y-catalyzed photooxidation of triarylphosphines under visible light irradiation and aerobic conditions. This new approach employed visible light as the energy source and air as the oxidant, showing great advantages in environmental benignness and operational easiness with a wide functional group tolerance.
- Zhang, Yanbin,Ye, Cong,Li, Shijie,Ding, Aishun,Gu, Guangxin,Guo, Hao
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p. 13240 - 13243
(2017/03/09)
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- Reversible Covalent and Supramolecular Functionalization of Water-Soluble Gold(I) Complexes
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The ligation of gold(I) metalloamphiphiles with biomolecules is reported, using water-soluble AuI-N-alkynyl substituted maleimide complexes. For this purpose, two different polar ligands were applied: 1) a neutral, dendritic tetraethylene glycol-functionalized phosphane and 2) a charged, sulfonated N-heterocyclic carbene (NHC). The retro Diels–Alder reaction of a furan-protected maleimide gold(I) complex, followed by cycloaddition with a diene-functionalized biotin under mild conditions leads to a novel gold(I) metalloamphiphile. The strong streptavidin–biotin binding affinity in buffered aqueous solution of the resulting biotin alkynyl gold(I) phosphane conjugate remains intact. The cytotoxicity of the biotinylated gold(I) complex against a T47D human breast cancer cell line is higher than for cisplatin.
- Kemper, Benedict,von Gr?ning, Maximilian,Lewe, Vanessa,Spitzer, Daniel,Otremba, Tobias,Stergiou, Natascha,Schollmeyer, Dieter,Schmitt, Edgar,Ravoo, Bart Jan,Besenius, Pol
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supporting information
p. 6048 - 6055
(2017/05/08)
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- Ir(III)-catalyzed direct C-H functionalization of arylphosphine oxides: A strategy for MOP-type ligands synthesis
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Diazo compounds as coupling partners are efficiently applied to Ir(III)-catalyzed direct C-H functionalization of arylphos-phine oxides. Involving C-H activation, carbene insertion, and tautomerism, this reaction proceeds under mild conditions, thus proving an approach to the synthesis of MOP-type ligand precursor in a single step. The utility of this transformation has been further demonstrated in ligand synthesis as well as in the construction of phosphole framework.
- Liu, Zhong,Wu, Ji-Qiang,Yang, Shang-Dong
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supporting information
p. 5434 - 5437
(2017/11/06)
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- The Influence of Peripheral Substituent Modification on PV, MnIII, and MnV(O) Corrolazines: X-ray Crystallography, Electrochemical and Spectroscopic Properties, and HAT and OAT Reactivities
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The influence of remote peripheral substitution on the physicochemical properties and reactivity of phosphorus and manganese corrolazine (Cz) complexes was examined. The substitution of p-MeO for p-t-Bu groups on the eight phenyl substituents of the β-car
- Joslin, Evan E.,Zaragoza, Jan Paulo T.,Baglia, Regina A.,Siegler, Maxime A.,Goldberg, David P.
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p. 8646 - 8660
(2016/11/09)
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- From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores
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New clustomesogens (i.e., metal atom clusters containing liquid crystalline (LC) materials) have been obtained by grafting neutral cyanobiphenyl (CB)- or cholesteryl-containing tailor-made dendritic mesomorphic triphenylphosphine oxide ligands on luminesc
- C?rcu, Viorel,Molard, Yann,Amela-Cortes, Maria,Bentaleb, Ahmed,Barois, Philippe,Dorcet, Vincent,Cordier, Stéphane
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supporting information
p. 10921 - 10925
(2015/09/15)
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- Iridium(III)-Catalyzed C H Amidation of Arylphosphoryls Leading to a P-Stereogenic Center
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Direct C H amidation of arylphosphoryl compounds has been developed by using an IrIIIcatalyst system under mild conditions. A wide range of substrates could be employed with high functional-group tolerance. This procedure was successfully applied for the first time to the asymmetric reaction giving rise to a P-chirogenic center with a high diastereomeric ratio of up to 19:1 (90 % de).
- Gwon, Donghyeon,Lee, Donggun,Kim, Jiyu,Park, Sehoon,Chang, Sukbok
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supporting information
p. 12421 - 12425
(2016/08/25)
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- Multifunctional crosslinkers for shape-memory polyimides, polyamides and poly(amide-imides) and methods of making the same
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Multifunctional amine crosslinkers that may be used to create crosslinked polyimide, polyamide, and poly(amide-imide) polymers and films having shape memory properties at elevated temperatures and methods of making the same.
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Page/Page column 7-8
(2013/10/08)
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- Phosphine-ligand decoration toward active and robust iron catalysts in LRP
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Phosphine ligands were designed to enhance the catalytic activity of iron(II) complexes [FeBr2(PR3)2] for metal-catalyzed living radical polymerization (LRP), and special efforts were directed to the improvement in catalyt
- Nishizawa, Keita,Ouchi, Makoto,Sawamoto, Mitsuo
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p. 3342 - 3349
(2013/07/11)
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- Ruthenium-catalyzed ortho -alkenylation of phenylphosphine oxides through regio- and stereoselective alkyne insertion into C-H bonds
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Direct ortho-substitution took place efficiently upon treatment of tri-, di-, and monoarylphosphine oxides with internal alkynes in the presence of a ruthenium catalyst to produce (o-alkenylphenyl)phosphine oxides regio- and stereoselectively. Chemoselective reduction of a product gave the corresponding (o-alkenylphenyl)phosphine, which may be useful as a ligand for transition metals.
- Itoh, Masaki,Hashimoto, Yuto,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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p. 8098 - 8104
(2013/09/12)
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- Redox properties of a mononuclear copper(II)-superoxide complex
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Redox properties of a mononuclear copper(II) superoxide complex, (L)Cu II-OO?, supported by a tridentate ligand (L = 1-(2-phenethyl)-5-[2-(2-pyridyl)ethyl]-1,5-diazacyclooctane) have been examined as a model compound of the putative reactive intermediate of peptidylglycine α-hydroxylating monooxygenase (PHM) and dopamine β-monooxygenase (DβM) (Kunishita et al. J. Am. Chem. Soc. 2009, 131, 2788-2789; Inorg. Chem. 2012, 51, 9465-9480). On the basis of the reactivity toward a series of one-electron reductants, the reduction potential of (L)CuII-OO ? was estimated to be 0.19 ± 0.07 V vs SCE in acetone at 298 K (cf. Tahsini et al. Chem. - Eur. J. 2012, 18, 1084-1093). In the reaction of TEMPO-H (2,2,6,6-tetramethylpiperidine-N-hydroxide), a simple HAT (hydrogen atom transfer) reaction took place to give the corresponding hydroperoxide complex LCuII-OOH, whereas the reaction with phenol derivatives (XArOH) gave the corresponding phenolate adducts, LCu II-OXAr, presumably via an acid-base reaction between the superoxide ligand and the phenols. The reaction of (L)CuII-OO ? with a series of triphenylphosphine derivatives gave the corresponding triphenylphosphine oxides via an electrophilic ionic substitution mechanism with a Hammett ρ value as -4.3, whereas the reaction with thioanisole (sulfide) only gave a copper(I) complex. These reactivities of (L)CuII-OO? are different from those of a similar end-on superoxide copper(II) complex supported by a tetradentate TMG 3tren ligand (1,1,1-Tris{2-[N2-(1,1,3,3- tetramethylguanidino)]ethyl}amine (Maiti et al. Angew. Chem., Int. Ed. 2008, 47, 82-85).
- Tano, Tetsuro,Okubo, Yuri,Kunishita, Atsushi,Kubo, Minoru,Sugimoto, Hideki,Fujieda, Nobutaka,Ogura, Takashi,Itoh, Shinobu
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p. 10431 - 10437
(2013/10/01)
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- Catalytic phosphorus(V)-mediated nucleophilic substitution reactions: Development of a catalytic appel reaction
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Catalytic phosphorus(V)-mediated chlorination and bromination reactions of alcohols have been developed. The new reactions constitute a catalytic version of the classical Appel halogenation reaction. In these new reactions oxalyl chloride is used as a consumable stoichiometric reagent to generate the halophosphonium salts responsible for halogenation from catalytic phosphine oxides. Thus, phosphine oxides have been transformed from stoichiometric waste products into catalysts and a new concept for catalytic phosphorus-based activation and nucleophilic substitution of alcohols has been validated. The present study has focused on a full exploration of the scope and limitations of phosphine oxide catalyzed chlorination reactions as well as the development of the analogous bromination reactions. Further mechanistic studies, including density functional theory calculations on proposed intermediates of the catalytic cycle, are consistent with a catalytic cycle involving halo- and alkoxyphosphonium salts as intermediates.
- Denton, Ross M.,An, Jie,Adeniran, Beatrice,Blake, Alexander J.,Lewis, William,Poulton, Andrew M.
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experimental part
p. 6749 - 6767
(2011/10/02)
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- Mechanistic study on photooxidation of triarylphosphines by time-resolved infrared spectroscopy
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Upon laser flash photolysis on a solution of triarylphosphine Ar 3P in acetonitrile or dichloromethane using a YAG laser at 266 nm, transient absorption was observed by time-resolved infrared spectroscopy. Rate constants were determined for the formation step of the absorption. Dependency of the rate on [Ar3P] and atmosphere, along with independent observation in laser flash photolysis/UV-Vis spectroscopy of the Ar3P solutions, suggeststhat electron transfer occurs from Ar3P to the singlet photoexcited state of Ar3P, generating triarylphosphine radical cation Ar3P .+, which reacts with a trace amount of H2O in the solvent to give the final product Ar3P O, which has been observed in steady-state photolysis. Copyright Taylor & Francis Group, LLC.
- Yasui, Shinro,Mishima, Masaaki
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experimental part
p. 838 - 840
(2011/06/25)
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- N,N-Dimethyl-S-difluoromethyl-S-phenylsulfoximinium tetrafluoroborate: A versatile electrophilic difluoromethylating reagent
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Over the past decade, sulfur-based fluoromethyl containing compounds have been exhaustively investigated as versatile fluoroalkylating reagents by our research laboratory as well as many others. Lately, we have designed a novel electrophilic difluoromethylating protocol employing in situ prepared N,N-dimethyl-S-difluoromethyl-S-phenylsulfoximinium salt. The present reagent provides excellent reactivity toward a broad spectrum of nucleophilic species (N-, P-, S-, and O-nucleophiles) to yield the corresponding difluoromethylated products with high efficacy under mild conditions. Additional studies have been performed to elucidate the mechanistic fundamentals of the reactions.
- Prakash, G.K. Surya,Zhang, Zhe,Wang, Fang,Ni, Chuanfa,Olah, George A.
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experimental part
p. 792 - 798
(2011/10/09)
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- A flash photolysis and theoretical study of the reaction of arylnitroso oxides with phosphorus(III) compounds
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The kinetic features of the reaction of aromatic nitroso oxides (ArNOO) with tri-n-butyl phosphite and substituted phosphines were studied by flash photolysis. It was shown that the trans-isomers of nitroso oxides enter into the reaction. The mechanism of the reaction was studied by theoretical methods, and the inertness of the cis-form of ArNOO was explained.
- Khursan,Kovaleva,Chainikova,Talipov,Safiullin
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experimental part
p. 284 - 289
(2011/11/12)
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- Synthesis of cationic rhenium(VII) oxo imido complexes and their tunability towards oxygen atom transfer
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A facile method is described for the synthesis of cationic Re(VII) cis oxo imido complexes of the form [Re(O)(NAr)(salpd)+] (salpd = N,N′-propane-1,3-diylbis(salicylideneimine)), 4, [Re(O)(NAr)(saldach) +] (saldach = N,N′-cyclohexane-1,3-diylbis(salicylideneimine)), 5, and [Re(O)(NAr)(hoz)2+] (hoz = 2-(2′- hydroxyphenyl)-2-oxazoline) (Ar = 2,4,6,-(Me)C6H2; 4-(CF3)C6H4; 4-(Me)C6H4; 4-(CF3)C6H4; 4-MeC6H 4SO2), 6, from the reaction of oxorhenium(V) [(L)Re(O)(Solv)+] (1-3) and aryl azides under ambient conditions. Unlike previously reported cationic Re(VII) dioxo complexes, these cationic oxo imido complexes can be obtained on a preparative scale, and an X-ray crystal structure of [Re(O)(NMes)(saldach)+], 5a, has been obtained. Despite the multiple stereoisomers that could arise from tetradentate ligation of salen ligands to rhenium, one major isomer is observed and isolated in each instant. The electronic rationalization for stereoselectivity is discussed. Investigation of the mechanism suggests that the reactions of Re(V) with aryl azides proceed through an azido adduct similar to the group 5 complexes of Bergman and Cummins. Treatment of the cationic oxo imido complexes with a reductant (PAr 3, PhSMe, or PhSH) results in oxygen atom transfer (OAT) and the formation of cationic Re(V) imido complexes. [(salpd)Re(NMes)(PPh 3)+] (7) and [(hoz)2Re(NAr)(PPh 3)+] (Ar = m-OMe phenyl) (9) have been isolated on a preparative scale and fully characterized including an X-ray single-crystal structure of 7. The kinetics of OAT, monitored by stopped-flow spectroscopy, has revealed rate saturation for substrate dependences. The different plateau values for different oxygen acceptors (Y) provide direct support for a previously suggested mechanism in which the reductant forms a prior-equilibrium adduct with the rhenium oxo (ReVII = O←Y). The second-order rate constants of OAT, which span more than 3 orders of magnitude for a given substrate, are significantly affected by the electronics of the imido ancillary ligand with electron-withdrawing imidos being most effective. However, the rate constant for the most active oxo imido rhenium(VII) is 2 orders of magnitude slower than that observed for the known cationic dioxo Re(VII) [(hoz) 2Re(O)2+].
- Ison, Elon A.,Cessarich, Jeanette E.,Travia, Nicholas E.,Fanwick, Phillip E.,Abu-Omar, Mahdi M.
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p. 1167 - 1178
(2008/04/18)
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- Efficient aerobic oxidation of phosphines, phosphites, and sulfides by using trialkylborane
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Treatment of phosphines, phosphites, or sulfides with trialkylborane under air afforded the corresponding oxides in good yields.
- Motoshima, Kosuke,Sato, Akinori,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 2229 - 2231
(2009/08/08)
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- Chemistry of singlet oxygen with arylphosphines
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The chemistry of singlet oxygen with a variety of arylphosphines has been studied. Rates of singlet oxygen removal by para-substituted arylphosphines show good correlation with the Hammett σ parameter (ρ=-1.53 in CDCl3), and with the Tolman electronic parameter. The only products for the reactions of these phosphines with singlet oxygen are the corresponding phosphine oxides. Conversely, for ortho-substituted phosphines with electron-donating substituents, there are two products, namely a phosphinate formed by intramolecular insertion and phosphine oxide. Kinetic analyses demonstrate that both products are formed from the same intermediate, and this allows determination of the rate ratios for the competing pathways. Increasing the steric bulk of the phosphine leads to an increase in the amount of insertion product. VT NMR experiments show that peroxidic intermediates can only be detected for very hindered and very electron-rich arylphosphines.
- Zhang, Dong,Ye, Bin,Ho, David G.,Gao, Ruomei,Selke, Matthias
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p. 10729 - 10733
(2007/10/03)
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- Effects of substituents on aryl groups during the reaction of triarylphosphine radical cation and oxygen
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In a previous report (S. Yasui, S. Tojo and T. Majima, J. Org. Chem., 2005, 70, 1276), we presented the results from the laser flash photolysis (LFP) and product analysis of the 9,10-dicyanoanthracene (DCA)-photosensitized oxidation of triarylphosphine (Ar3P) in acetonitrile under air, which showed that the photoreaction results in the oxidation of Ar3P to give the corresponding phosphine oxide (Ar3PO) in a nearly quantitative yield, and that the reaction is initiated by the electron transfer (ET) from Ar 3P to DCA in the singlet excited state (1DCA*), producing the triarylphosphine radical cation Ar3P+. This radical cation decays through radical coupling with O2 to afford the peroxy radical cation Ar3P+-O-O, which we proposed to be the intermediate leading to the product Ar3PO. We now examined this photoreaction in more detail using ten kinds of Ar3P with various electronic and steric characteristics. The decay rate of Ar3P + measured by the LFP was only slightly affected by the substituents on the aryl groups of Ar3P. During the photolysis of trimesitylphosphine (Mes3P), the peroxy radical cation intermediate (Mes3P+-O-O) had a lifetime long enough to be spectrophotometrically detected. The quantum yields of Ar3PO increased with either electron-withdrawing or -releasing substituents on the aryl groups, suggesting that a radical center is developed on the phosphorus atom during the step when the quantum yield is determined. In addition, the o-methyl substituents in Ar3P decreased the quantum yield. These results clearly indicated that Ar3P+-O-O undergoes radical attack upon the parent phosphine Ar3P that eventually produces the final product, Ar3PO. The Royal Society of Chemistry 2006.
- Yasui, Shinro,Tojo, Sachiko,Majima, Tetsuro
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p. 2969 - 2973
(2008/02/11)
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- Reaction of triarylphosphine radical cations generated from photoinduced electron transfer in the presence of oxygen
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(Chemical Equation Presented) The 9,10-dicyanoanthracene (DCA)-sensitized photoreaction of triarylphosphines (1) was carried out in acetonitrile under aerobic conditions. Phosphine 1 was oxidized to the corresponding phosphine oxide with no appreciable side reactions. Product analysis and laser flash photolysis experiments suggest that the radical cation of 1 formed by the electron transfer from 1 to DCA in the singlet excited state ( 1DCA*) reacts with O2 to eventually afford the phosphine oxide.
- Yasui, Shinro,Tojo, Sachiko,Majima, Tetsuro
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p. 1276 - 1280
(2007/10/03)
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- Catalytic asymmetric cyano-ethoxycarbonylation reaction of aldehydes using a YLi3tris(binaphthoxide) (YLB) complex: Mechanism and roles of achiral additives
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Full details of a catalytic asymmetric cyano-ethoxycarbonylation reaction promoted by a heterobimetallic YLi3tris(binaphthoxide) complex (YLB 1), especially mechanistic studies, are described. In the cyanation reaction of aldehydes with ethyl c
- Yamagiwa, Noriyuki,Tian, Jun,Matsunaga, Shigeki,Shibasaki, Masakatsu
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p. 3413 - 3422
(2007/10/03)
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- Mechanisms of hydrogen-, oxygen-, and electron-transfer reactions of cumylperoxyl radical
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Rates of hydrogen-transfer reactions from a series of para-substituted N,N-dimethylanilines to cumylperoxyl radical and oxygen-transfer reactions from cumylperoxyl radical to a series of sulfides and phosphines have been determined in propionitrile (EtCN) and pentane at low temperatures by use of ESR. The observed rate constants exhibit first-order and second-order dependence with respect to concentrations of N,N-dimethylanilines. This indicates that the hydrogen- and oxygen-transfer reactions proceed via 1:1 charge-transfer (CT) complexes formed between the substrates and cumylperoxyl radical. The primary kinetic isotope effects are determined by comparing the rates of N,N-dimethylanilines and the corresponding N,N-bis(trideuteriomethyl)anilines. The isotope effect profiles are quite different from those reported for the P-450 model oxidation of the same series of substrates. Rates of electron-transfer reactions from ferrocene derivatives to cumylperoxyl radical have also been determined by use of ESR. The catalytic effects of Sc(OTf)3 (OTf = triflate) on the electron-transfer reactions are compared with those of Sc(OTf)3 on the hydrogen- and oxygen-transfer reactions. Such comparison provides strong evidence that the hydrogen- and oxygen- transfer reactions of cumylperoxyl radical proceed via a one-step hydrogen atom and oxygen atom transfer rather than via an electron transfer from substrates to cumylperoxyl radical.
- Fukuzumi, Shunichi,Shimoosako, Kanji,Suenobu, Tomoyoshi,Watanabe, Yoshihito
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p. 9074 - 9082
(2007/10/03)
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- Synthesis of a family of triarylphosphanes with fluorous phase affinity
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A very efficient synthesis of new perfluoro-functionalized triarylphosphanes using an oxygen substituent as the branching point for the introduction of the perfluoro chain has been developed. This approach enabled the introduction of the perfluoro tail at the para, meta, and oitho position, giving highly perfluorinated analogues of triphenylphosphane con-taining between 54 and 59 wt% fluorine. This methodology has been extended to the synthesis of a perfluoro analogue of l,2-bis(diphenylphosphanyl)ethane. Fluorous/organic partition coefficients of some of the perfluorophosphanes have been measured, as well as their rates of oxidation. WILEY-VCH Verlag GmbH, 2002.
- Sinou, Denis,Maillard, David,Pozzi, Gianluca
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p. 269 - 275
(2007/10/03)
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- Stoichiometric and catalytic oxygen activation by trimesityliridium(III)
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Trimesityliridium(III) (mesityl = 2,4,6-trimethylphenyl) reacts with O2 to form oxotrimesityliridium(V), (mes)3Ir=O, in a reaction that is cleanly second order in iridium. In contrast to initial reports by Wilkinson, there is no evidence for substantial accumulation of an intermediate in this reaction. The oxo complex (mes)3Ir=O oxidizes triphenylphosphine to triphenylphosphine oxide in a second-order reaction with ΔH? = 10.04 ± 0.16 kcal/mol and ΔS? = -21.6 ± 0.5 cal/(mol·K) in 1,2-dichloroethane. Triphenylarsine is also oxidized, though over an order of magnitude more slowly. Ir(mes)3 binds PPh3 reversibly (Kassoc = 84 ± 3 M-1 in toluene at 20°C) to form an unsymmetrical, sawhorse-shaped four-coordinate complex, whose temperature-dependent NMR spectra reveal a variety of dynamic processes. Oxygen atom transfer from (mes)3Ir=O and dioxygen activation by (mes)3Ir can be combined to allow catalytic aerobic oxidations of triphenylphosphine at room temperature and atmospheric pressure with overall activity (~60 turnovers/h) comparable to the fastest reported catalysts. A kinetic model that uses the rates measured for dioxygen activation, atom transfer, and phosphine binding describes the observed catalytic behavior well. Oxotrimesityliridium does not react with sulfides, sulfoxides, alcohols, or alkenes, apparently for kinetic reasons.
- Jacobi, Bridey Grant,Laitar, David S.,Pu, Lihung,Wargocki, Michael F.,DiPasquale, Antonio G.,Fortner, Kevin C.,Schuck, Stephany M.,Brown, Seth N.
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p. 4815 - 4823
(2008/10/08)
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- Reaction of arylphosphines with singlet oxygen: intra- vs intermolecular oxidation.
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[reaction--see text] The chemistry of singlet oxygen with all three isomers of tris(methoxyphenyl)phosphine has been studied. For the severely hindered ortho isomer, intramolecular rearrangement to form phenyl diphenyl phosphinate is preferred to formatio
- Gao,Ho,Dong,Khuu,Franco,Sezer,Selke
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p. 3719 - 3722
(2007/10/03)
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- A convenient access to triarylphosphines with fluorous phase affinity
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Perfluorocarbon-soluble triarylphosphines with electronic properties similar to those of tris(p-methoxyphenyl)phosphine can be easily prepared through O-alkylation of tris(p-hydroxyphenyl)phosphine oxide and subsequent reduction with trichlorosilane.
- Sinou, Denis,Pozzi, Gianluca,Hope, Eric G.,Stuart, Alison M.
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p. 849 - 852
(2007/10/03)
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- synthesis and Solid-State Structure of Substituted Arylphosphine Oxides
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We described the preparation and characterization of several new arylphosphine oxides, which are of interest as second-order nonlinear optical materials. (4-Aminophenyl)diphenylphosphine oxide (1a), bis(4-aminophenyl)phenylphosphine oxide (2a), and (4-aminophenyl)bisphosphine oxide (5) were prepared by addition of aryl Grignard and organolithium reagents containing protected amines to phosphorus oxyhalides.Alternatively, 1a was prepared by treatment of (4-bromophenyl)diphenylphosphine oxide with azidomethyl phenyl sulfide, followed by hydrolysis. (4-Aminophenyl)(4'-nitrophenyl)phenylphosphine oxide (6) was prepared by nucleophilic aromatic substitution of bis(4-fluorophenyl)phenylphosphine oxide to give the corresponding dinitro compound, followed by selective mono-reduction.The X-ray crystal structure of (4-aminophenyl)diphenylphosphine oxide (1a), along with those of mono-, di-, and trihydroxy triphenylphosphine oxides 1b, 2b, and 3b, exhibit extensive intermolecular hydrogen bonding.The hydrogen bonding in 1a and 1b produces chains of arylphosphine oxide molecules with a head-to-tail alignment; the chains pack in an antiparallel manner to produce solid-state structures that display only slight deviations from centrosymmetry.
- Whitaker, Craig M.,Kott, Kevin L.,McMahon, Robert J.
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p. 3499 - 3508
(2007/10/02)
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- N-Phenyl-P,P,P-triarylphospha-λ5-azenes, Triarylphosphines, and Triarylphosphine Oxides. Substituent Effects on 15N, 31P, and 13C NMR Spectra
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The syntheses and 15N, 31P, and 13C NMR spectra of a series of N-phenyl-P,P,P-triarylphospha-λ5-azenes 4 and the 31P and 13C NMR spectra of the corresponding series of triarylphosphines 5 and triarylphosphine oxides 6 are reported.The substituent effects on the chemical shifts can be best accommodated and rationalized by use of a model for system 4 whereby the dipole of the aryl group and its pendant R group polarizes the rest of the molecule.This includes the P and N atoms and phenyl ring, where an electron-withdrawing R group increases the electron density of the P, N, and ipso C-1 while decreasing the electron density on C-3 and C-4 of the N-phenyl ring (Figure 3).A similar polarization pattern for the phosphine oxide series 6 is suggested.In the phosphine series 5, the chemical shift data is consistent with the lone electron pair on the phosphorus atom delocalizing into the aryl rings.The coupling constant data, in particular 1JPN for series 4 and 1JPC for series 4-6, were examined with use of the Hammett monosubstituent parameter (MSP) and the Taft dual-substituent parameter (DSP) approaches.For systems 4 and 6, without a lone electron pair on the phosphorus atom, a better electron-donating substituent increases the one-bond P-C(Ar) coupling constant.On the contrary, in the phosphine series 5, where there is a lone electron pair on the phosphorus, a better electron-withdrawing substituent increases the one-bond P-C(Ar) coupling constant.DSP treatment of 1JPC, and comparing to the few related systems in the literature,shows three types of systems.One, which includes 4 and 6, has an atom, phosphorus in these cases, that does not have a lone pair of electrons attached to the ring to which is attached an atom with a lone pair of electrons.Here, the resonance effect on 1JPC predominates.A second series, which includes phosphines 5, has a lone pair on the atom attached to the aryl ring.In these cases, the resonance effect is ca. 50percent greater than the inductive effect.Finally, the third series, exemplified by two examples from the literature, has a tetrahedral atom (without a lone pair) attached to the aryl ring and this in turn is attached to tetrahedral atoms without lone electron pairs.In these case, the resonance and inductive effects are fairly comparable.
- Chou, Whe-Narn,Pomerantz, Martin
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p. 2762 - 2769
(2007/10/02)
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- Sterically encumbered functional groups: An investigation of endo versus exo phosphoryl complexation using 1H and 31P NMR
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The synthesis of phosphine oxide bifunctional macrocycles 1-4 is reported. Additionally, the X-ray crystal structures for exo-exo diyne 1 and endo-exo hosts 2 and 4 are presented. Assignment of the two phosphorus signals in the 31P NMR spectra of 2 and 4 and the aromatic proton signals in the 1H NMR spectra of 2 and 4 is reported. The complexation behavior of macrocycles 1-4 and precyclophane 8 with a variety of neutral organic guests and Ph2SnCl2 is investigated by using 1H and 31P NMR as investigative instrumental probes. Initial endo complexation is the preferred mechanism in the 1:2 complexation of 2 with guests, while initial exo complexation is preferred for the complexation of 4 with guests. 2 forms 1:2 complexes with pentafluorophenol, 2,6-dimethyl-4-nitrophenol, and acetic acid via initial exo complexation. Association constants determined from these experiments reveal that the exo phosphoryl binding site in 4 is higher than those in the other reported phosphine oxides. An X-ray crystal structure of the 1:1 complex of 4 with diphenyltin dichloride was obtained to explore this anomaly, and it is reported.
- Friedrichsen, Bernard P.,Powell, Douglas R.,Whitlock, Howard W.
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p. 8931 - 8941
(2007/10/02)
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- The Mechanisms of the Conversion of Thiophosphoryl Compounds into their Phosphoryl Analogues by Photochemically Excited 3-Methylpyridazine 2-Oxide and by 2-Methyl-3-p-nitrophenyloxaziridine; a Comparison
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Reactions of tri-p-substituted triarylphosphine sulphides with 3-methylpyridazine 2-oxide, under photolysis, and with 2-methyl-3-p-nitrophenyloxaziridine both give the corresponding phosphine oxides.A detailed study and comparison of the two reactions shows that they are mechanistically quite distinct and that it is unlikely that the active oxygenating species generated by photolysis of the N-oxide, which attacks the phosphine sulphides, is an oxaziridine.The evidence presented suggests that this species may in fact be 'oxene'.
- Rowley, Alan G.,Steedman, John R. F.
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p. 1113 - 1120
(2007/10/02)
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- Reaction of Tetramethyl-1,2-dioxetane with Triphenylphosphine: Activation Parameters for the Formation of 2,2-Dihydro-4,4,5,5-tetramethyl-2,2,2-triphenyl-1,3,2-dioxaphospholane
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The reaction of tetramethyl-1,2-dioxetane (1) and triphenylphosphine (2) in benzene-d6 produced 2,2-dihydro-4,4,5,5-tetramethyl-2,2,2-triphenyl-1,3,2-dioxaphospholane (3) in about 90percent yield over the temperature range 6-60 deg C.Pinacolone and triphenylphosphine oxide (4) were the major side products .Thermal decomposition of 3 produced only 4 and 5.Kinetic studies were carried out by the chemiluminescence method.The rate of phosphorane was found to be first order with respect to each reagent.The activation parameters for the reaction of 1 and 2 were: Ea = 9.8+/-0.6 kcal/mole; ΔS = -28 eu; k30 deg C = 1.8 m-1sec-1 (range = 10-60 deg C).Preliminary results for the reaction of 1 and tris(p-chlorophenyl)phosphine were Ea about 11 kcal/mol, ΔS = -24 eu, k30 deg C = 1.3 M-1sec-1 while those for the reaction of 1 and tris(p-anisyl)phosphine were: Ea about 8.6 kcal/mol, ΔS = -29 eu k30 deg C = 4.9 M-1sec-1.
- Baumstark, Alfons L.,Barrett, Morgan,Kral, Kathleen M.
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p. 201 - 203
(2007/10/02)
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- Reaction of Triarylphosphines with Tetramethyl-1,2-dioxetane: Kinetics of Formation and Decomposition of 2,2-Dihydro-4,4,5,5-tetramethyl-2,2,2-triaryl-1,3,2-dioxaphospholanes
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The reaction of a series of triarylphosphines with tetramethyl-1,2-dioxetane (1) in C6D6 produced a series of 2,2-dihydro-4,4,5,5-tetramethyl-2,2,2-triaryl-1,3,2-dioxaphospholanes in high yield.Thermal decomposition of the phosphoranes produced tetramethylethylene oxide and the corresponding triarylphosphine oxides in all cases.The kinetics of phosphorane formation and decomposition in benzene was investigated.The rate data for phosphorane formation showed a reasonable correlation with ?+ constants (correlation coefficient ca 0.98: ρ = -0.82).Theresults are not consistent with nucleophilic attack on oxygen by phosphorus but rather with a concerted (biphilic) insertion into the peroxy bond of the dioxetane.Phosphorane decomposition (at 38 deg C) was found to be substantially more sensitive to substituent effects than phosphorane formation.A good correlation of phosphorane decomposition with Hammett ? constants was obtained (correlation coefficient = 0.997, ρ = -3.51 +/- 0.24).This result is consistent with a mechanism that involves heterolytic cleavage of a phosphorus-oxygen bond followed by the irreversible internal displacement of triarylphosphine oxide.
- Baumstark, Alfons L.,McCloskey, Candice J.,Williams, Timothy E.,Chrisope, Douglas R.
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p. 3593 - 3597
(2007/10/02)
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