- Dimetalla-heterocyclic carbenes: The interconversion of chalcocarbonyl and carbido ligands
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The l-carbido complexes [Rh2(l-C)Cl2(PPh3)4] and [Rh2(l-C)Cl2(dppm)2] cleave CS2 to afford themonothiocarbonyl complexes [RhCl(CS)(PPh3)2] and [Rh2(l-CS)Cl2(dppm)2]. The latter reacts with dimethyl acetylenedicarboxylate (DMAD) to afford [Rh(l-CS)(l-DMAD)
- Barnett, Harrison J.,Hill, Anthony F.
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- Sulfur-based redox reactions in Mo3S74+ and Mo3S44+ clusters bearing halide and 1,2-dithiolene ligands: A mass spectrometric and density functional theory study
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The gas phase fragmentation reactions of sulfur-rich [Mo3S 7Br6]2- (12-), [Mo3S 7(bdt)3]2- (22-), and [Mo 3S4(bdt)3]2- (32-) (bdt = benzenedithiolate) complexes have been investigated by electrospray ionization (ESI) tandem mass spectrometry and theoretical calculations at the density functional theory level. Upon collision induced dissociation (CID) conditions, the brominated 12- dianion dissociates through two sequential steps that involves a heterolytic Mo-Br cleavage to give [Mo3S 7Br5]- plus Br- followed by a two-electron redox process that affords [Mo3S5Br 5]- and diatomic S2 sulfur. Dianion [Mo 3S7(bdt)3]2- (22-) dissociates through two sequential redox processes evolving diatomic S 2 sulfur and neutral bdt to yield [Mo3S 5(bdt)3]2- and [Mo3S 5(bdt)2]2-, respectively. Conversely, dianion [Mo3S4(bdt)3]2- (32-), with sulfide instead of disulfide S22- bridged ligands, remains intact under identical fragmentation conditions, thus highlighting the importance of disulfide ligands (S22-) as electron reservoirs to trigger redox reactions. Regioselective incorporation of 34S and Se at the equatorial position of the Mo3S 7 cluster core in 12- and 22- have been used to identify the product ions along the fragmentation pathways. Reaction mechanisms for the gas-phase dissociation pathways have been elucidated by means of B3LYP calculations, and a comparison with the solution reactivity of Mo 3S7 and Mo3S4 clusters as well as closely related Mo/S/dithiolene systems is also discussed.
- Llusar, Rosa,Polo, Victor,Velez, Ederley,Vicent, Cristian
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- Chemistry of [CpCr(CO)3]2. Synthesis of Cp2Cr2(CO)4S, Cp2Cr2(CO)4S2, and Cp2Cr2(CO)5S2. Crystal structure and reactivity of Cp2Cr2(CO)4S2 and Cp2Cr2(CO)5S2
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The instantaneous reaction of [CpCr(CO)3]2 (Cp = η5-C5H5) in tetrahydrofuran or toluene with stoichiometric amounts of elemental sulfur produced Cp2Cr2(CO)4S (1) and Cp2Cr2(CO)5S2 (2) in near quantitative yields. A solution of 2 on standing 1 h at ambient temperature gave a mixture of Cp2Cr2(CO)4S2 (3) (76%) and 1. The transformation of the very labile complex 2 to 3 with the cleavage of a CO ligand thence to the linear multiple bonded Cr-S-Cr complex 1 with extrusion of a S atom and finally to Cp4Cr4S4 was demonstrated by a time-dependent NMR study at 30°C. When 2 was treated with CF3SO3CH3, one of the S atoms was immediately methylated, giving [Cp2Cr2(CO)5S2(CH 3)](SO3CF3) (4) as a fine black unstable solid, which decomposed in solution to give 1 and [Cp4Cr4S4(CH3)](SO 3CF3) (5). Complexes 1-3 have been characterized by elemental, spectral, and crystal structure analyses. The structure of 1 has been reported previously. Crystals of 2 are monoclinic, P21/n, with a = 11.638 (4) A?, b = 15.508 (5) A?, c = 9.825 (3) A?, β = 111.56 (2)°, and Z = 4. Crystals of 3 are monoclinic, P21/c, with a = 8.214 (1) A?, b = 11.464 (2) A?, c = 16.182 (3) A?, β = 92.44 (1)°, and Z = 4. The disulfur ligand bridges the two chromium centers asymmetrically μ-η1,η2 in 2 and symmetrically μ-η2 in 3. S-S distances [2.010 (4) A?, 2; 1.990 (1) A?, 3] are similar to those found in other transition-metal μ-S2 complexes. Metal atoms in both complexes exhibit 4:3, 7-coordination.
- Goh, Lai Yoong,Hambley, Trevor W.,Robertson, Glen B.
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- Crystal Structure of a Novel Tetranuclear Dithiocarboxylato Copper(I) Complex, 4(PPh3)2
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The complex 4(PPh3)2> (1) was obtained by reaction of 4> with PPh3 in toluene in a ratio Cu:P=1:1.5.Its structure, determined by X-ray diffraction methods, shows a distorted trigonal-pyramidal arrangement of four copper atoms, with four surrounding dithiocarboxylate groups acting as triply bridging ligands.Three of the ligands bridge the apical and two basal metal atoms, the fourth bridges the three basal copper atoms.Crystals of (1) are triclinic, space group P, with Z=2 in a unit cell of dimensions a=12.995(3), b=15.783(4), c=16.002(5) Angstroem, α=83.66(2), β=102.97(3), and γ=93.38(2) deg.The structure has been solved by direct and Fourier methods and refined by block-matrix least squares to R=0.073 for 3978 observed reflections.
- Lanfredi, Anna Maria Manotti,Tiripicchio, Antonio,Camus, Annamaria,Marsich, Nazario
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- New Macrocyclic Complexes of Titanum(IV): Synthesis, Reactivity, and X-Ray Crystal Structure of the Trigonal Prismatic Ti(C22H22N4)Cl2, and Synthesis and Reactivity of its Peroxo, Disulphido, and Pyrocatecholato Derivatives
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The new macrocyclic complex of titanum(IV), Ti(C22H22N4)Cl2 has been shown by X-ray crystallography to have a trigonal prismatic co-ordination geometry; the synthesis and reactivities of the peroxo, disulphido, and pyrocatecholato derivatives are discussed.
- Goedken, Virgil L.,Ladd, Judith A.
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- Formation of a methine carbon-to-rhenium σ bond in an oxorhenium(V)-benzothiazole complex
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The reaction of trans-[ReOCl3(PPh3)2] with 1-(1,3-benzothiazol-2-yl)-3-benzoylthiourea (Hbbt) in methanol led to the isolation of the complex [ReOCl2(cbt)(PPh3)] (1). It contains the monoanionic bidentate chelate N-((benzothiazol-2-ylamino)methylene)benzamide (cbt). The new ligand cbt is coordinated via a neutral ketonic oxygen and an anionic imino-acyl carbon atom, and was formed by the abstraction of the thionyl sulfur of Hbbt by a triphenylphosphine of the starting complex, with S = PPh3 also been formed as by-product. Compound 1 was characterized by elemental analysis, FTIR, proton NMR and single crystal X-ray diffraction.
- Schoultz,Gerber,Hosten
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- Tungsten Ligand-Based Sulfur-Atom-Transfer Catalysts: Synthesis, Characterization, Sustained Anaerobic Catalysis, and Mode of Aerial Deactivation
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The synthesis, properties, X-ray structures, and catalytic sulfur-atom-transfer (SAT) reactions of W2(μ-S)(μ-S2)(dtc)2(dped)2 [1; dtc = S2CNR2-, where R = Me, Et, iBu, and Bn; dped = S2C2Ph22-] and W2(μ-S)2(dtc)2(dped)2 (2) are reported. These complexes represent the oxidized (1) and reduced (2) forms of anaerobic SAT catalysts operating through the bidirectional, ligand-based half-reaction (μ-S)(μ-S2) ? (μ-S)2 + S0. The catalysts are deactivated in air through the formation of catalytically inactive oxo complexes, (dtc)WO(μ-S)(μ-dped)W(dtc)(dped) (3), prompting us to recommend that group 6 SAT activity be assessed under strictly anaerobic conditions.
- Ward, James P.,Lim, Patrick J.,Evans, David J.,White, Jonathan M.,Young, Charles G.
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- Reactions of triphenylphosphine with S4N3Cl
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It has been shown that S4N3Cl gives a complex series of reactions in which [(C6H5)3P=NP(C6H5) 3]Cl (I), [(C6H5)3PNH2]Cl (II), and [{(C6H5)3PN}3S]Cl3 (III) are produced. Compound III reacts with two molecules of triphenylphosphine giving [{(C6H5)3PN}3S]Cl 3·2P(C6H5)3 (IV), which crystallizes out of acetone with 2 moles of acetone. N-Chlorotriphenylphosphinimine is suggested as a probable intermediate in these reactions.
- Prakash, Hari,Sisler, Harry H.
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- Reversible chalcogen-atom transfer to a terminal uranium sulfide
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The reaction of elemental S or Se with [K(18-crown-6)][U(S)(NR2)3] (1) results in the formation of the new uranium(IV) dichalcogenides [K(18-crown-6)][U(η2-S2)(NR2)3] (2) and [K(18-crown-6)][U(η2-SSe)(NR2)3] (5). The further addition of elemental S to 2 results in the formation of [K(18-crown-6)][U(η3-S3)(NR2)3] (3). Complexes 2, 3, and 5 can be reconverted into 1 via the addition of R3P (R = Et, Ph), concomitant with the formation of R3P=E (E = S, Se).
- Smiles, Danil E.,Wu, Guang,Hayton, Trevor W.
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- Evidence for the formation of isothiocyanate during sulfurisation of phosphines and phosphites using xanthane hydride
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Contrary to a previous report, the sulfurisation of triphenylphosphines and trialkyl phosphites by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products but unstable thiocarbamoyl isothiocyanate which has been trapped with nucleophiles.
- Hanusek, Ji?í,Russell, Mark A.,Laws, Andrew P.,Page, Michael I.
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- Terminal Uranium(V/VI) Nitride Activation of Carbon Dioxide and Carbon Disulfide: Factors Governing Diverse and Well-Defined Cleavage and Redox Reactions
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The reactivity of terminal uranium(V/VI) nitrides with CE2(E=O, S) is presented. Well-defined C=E cleavage followed by zero-, one-, and two-electron redox events is observed. The uranium(V) nitride [U(TrenTIPS)(N)][K(B15C5)2] (1, TrenTIPS=N(CH2CH2NSiiPr3)3; B15C5=benzo-15-crown-5) reacts with CO2to give [U(TrenTIPS)(O)(NCO)][K(B15C5)2] (3), whereas the uranium(VI) nitride [U(TrenTIPS)(N)] (2) reacts with CO2to give isolable [U(TrenTIPS)(O)(NCO)] (4); complex 4 rapidly decomposes to known [U(TrenTIPS)(O)] (5) with concomitant formation of N2and CO proposed, with the latter trapped as a vanadocene adduct. In contrast, 1 reacts with CS2to give [U(TrenTIPS)(κ2-CS3)][K(B15C5)2] (6), 2, and [K(B15C5)2][NCS] (7), whereas 2 reacts with CS2to give [U(TrenTIPS)(NCS)] (8) and “S”, with the latter trapped as Ph3PS. Calculated reaction profiles reveal outer-sphere reactivity for uranium(V) but inner-sphere mechanisms for uranium(VI); despite the wide divergence of products the initial activation of CE2follows mechanistically related pathways, providing insight into the factors of uranium oxidation state, chalcogen, and NCE groups that govern the subsequent divergent redox reactions that include common one-electron reactions and a less-common two-electron redox event. Caution, we suggest, is warranted when utilising CS2as a reactivity surrogate for CO2.
- Cleaves, Peter A.,Kefalidis, Christos E.,Gardner, Benedict M.,Tuna, Floriana,McInnes, Eric J. L.,Lewis, William,Maron, Laurent,Liddle, Stephen T.
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- Reactivity of a Nickel Sulfide with Carbon Monoxide and Nitric Oxide
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The reactivity of the "masked" terminal nickel sulfide complex, [K(18-crown-6)][(LtBu)NiII(S)] (LtBu = {(2,6-iPr2C6H3)NC(tBu)}2CH), with the biologically important small molecules CO and NO, was surveyed. [K(18-crown-6)][(LtBu)NiII(S)] reacts with carbon monoxide (CO) via addition across the Ni-S bond to give a carbonyl sulfide complex, [K(18-crown-6)][(LtBu)NiII(S,C:β2-COS)] (1). Additionally, [K(18-crown-6)][(LtBu)NiII(S)] reacts with nitric oxide (NO) to yield a nickel nitrosyl, [(LtBu)Ni(NO)] (2), and a perthionitrite anion, [K(18-crown-6)][SSNO] (3). The isolation of 3 from this reaction confirms, for the first time, that transition metal sulfides can react with NO to form the biologically important [SSNO]· anion.
- Hartmann, Nathaniel J.,Wu, Guang,Hayton, Trevor W.
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- Synthesis and stability of sulfur-35 labelled 4-ethylbicyclothiophosphate
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Different synthetic routes to the preparation of 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2,2,2]octane-1-thioxide labelled with sulfur-35 have been investigated since it is of considerable interest as radioligand for neurochemistry. The thiophosphate was successfully synthesized by sulfuration of the corresponding bicyclophosphite by elemental sulfur-3 5, however the radiochemical purity of the material obtained in this way proves to be low. Convenient methods for synthesis of the thioxide from [35S] thiourea, based on the results of the autoradiolysis of the starting [35S] thiourea, has been discovered giving rise to thioxide with high radiochemical purity. The autoradiolytic stability of the labelled thiophosphate has been studied. 1999 KluwerAcademic/Plenum Publishers.
- Tkachenko,Trofimova,Fedoseev
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- Site-Specific Incorporation of a Photoactivatable Fluorescent Amino Acid
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Photoactivatable fluorophores are emerging optical probes for biological applications. Most photoactivatable fluorophores are relatively large in size and need to be activated by ultraviolet light; this dramatically limits their applications. To introduce photoactivatable fluorophores into proteins, recent investigations have explored several protein-labeling technologies, including fluorescein arsenical hairpin (FlAsH) Tag, HaloTag labeling, SNAPTag labeling, and other bioorthogonal chemistry-based methods. However, these technologies require a multistep labeling process. Here, by using genetic code expansion and a single sulfur-for-oxygen atom replacement within an existing fluorescent amino acid, we have site-specifically incorporated the photoactivatable fluorescent amino acid thioacridonylalanine (SAcd) into proteins in a single step. Moreover, upon exposure to visible light, SAcd can be efficiently desulfurized to its oxo derivatives, thus restoring the strong fluorescence of labeled proteins.
- Tang, Juan,Yu, Chenfei,Loredo, Axel,Chen, Yuda,Xiao, Han
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p. 501 - 504
(2020/11/03)
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- Synthesis of Glycosyl Fluorides by Photochemical Fluorination with Sulfur(VI) Hexafluoride
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This study describes a new convenient method for the photocatalytic generation of glycosyl fluorides using sulfur(VI) hexafluoride as an inexpensive and safe fluorinating agent and 4,4′-dimethoxybenzophenone as a readily available organic photocatalyst. This mild method was employed to generate 16 different glycosyl fluorides, including the substrates with acid and base labile functionalities, in yields of 43%-97%, and it was applied in continuous flow to accomplish fluorination on an 7.7 g scale and 93% yield.
- Bannykh, Anton,Khomutnyk, Yaroslav,Kim, Sungjin,Nagorny, Pavel
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supporting information
p. 190 - 194
(2021/01/13)
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- Heteroleptic Samarium(III) Chalcogenide Complexes: Opportunities for Giant Exchange Coupling in Bridging σ- And π-Radical Lanthanide Dichalcogenides
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The introduction of (N2)3-? radicals into multinuclear lanthanide molecular magnets raised hysteresis temperatures by stimulating strong exchange coupling between spin centers. Radical ligands with larger donor atoms could promote more efficient magnetic coupling between lanthanides to provide superior magnetic properties. Here, we show that heavy chalcogens (S, Se, Te) are primed to fulfill these criteria. The moderately reducing Sm(II) complex, [Sm(N??)2], where N?? is the bulky bis(triisopropylsilyl)amide ligand, can be oxidized (i) by diphenyldichalcogenides E2Ph2 (E = S, Se, Te) to form the mononuclear series [Sm(N??)2(EPh)] (E = S, 1-S; Se, 1-Se, Te, 1-Te); (ii) S8 or Se8 to give dinuclear [{Sm(N??)2}2(μ-η2:η2-E2)] (E = S, 2-S2; Se, 2-Se2); or (iii) with Te=PEt3 to yield [{Sm(N??)2}(μ-Te)] (3). These complexes have been characterized by single crystal X-ray diffraction, multinuclear NMR, FTIR, and electronic spectroscopy; the steric bulk of N?? dictates the formation of mononuclear complexes with chalcogenate ligands and dinuclear species with the chalcogenides. The Lα1 fluorescence-detected X-ray absorption spectra at the Sm L3-edge yielded resolved pre-edge and white-line peaks for 1-S and 2-E2, which served to calibrate our computational protocol in the successful reproduction of the spectral features. This method was employed to elucidate the ground state electronic structures for proposed oxidized and reduced variants of 2-E2. Reactivity is ligand-based, forming species with bridging superchalcogenide (E2)-? and subchalcogenide (E2)3-? radical ligands. The extraordinarily large exchange couplings provided by these dichalcogenide radicals reveal their suitability as potential successors to the benchmark (N2)3-? complexes in molecular magnets.
- Dimucci, Ida M.,Giansiracusa, Marcus J.,Goodwin, Conrad A. P.,Kragskow, Jon G. C.,Lancaster, Kyle M.,Mills, David P.,Réant, Benjamin L. L.,Sproules, Stephen,Vettese, Gianni F.
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supporting information
(2020/06/08)
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- Nitrosonium reactivity of (NHC)Copper(I) sulfide complexes
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This study examines the reactivity of a series of copper(I) sulfide complexes stabilized by the expanded-ring N-heterocyclic carbene (NHC) 1,3-bis(2,6-diisopropylphenyl)-4,5,6,7-tetrahydro-1,3-diazepin-2-ylidene (7Dipp) toward the nitrosonium ion (NO+). 7Dipp is shown to support neutral sulfide- and disulfide-bridged dicopper(I) complexes, as well as mononuclear copper(I) hydrosulfide. The addition of NO+ to each of these results in the formation of NHC-supported copper(I) cations and elemental sulfur. Reduction of copper(I) to copper(0) is observed upon reaction of NO+ with dicopper(I) sulfide or disulfide, whereas ammonium ion formation is observed upon reaction of copper(I) hydrosulfide with NO+. Ammonium ion formation is likewise observed upon reaction of NO+ with (7Dipp)copper(I) hydride.
- Jordan, Abraham J.,Walde, Rebecca K.,Schultz, Kelly M.,Bacsa, John,Sadighi, Joseph P.
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supporting information
p. 9592 - 9596
(2019/08/22)
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- Synthesis of Phosphine Chalcogenides Under Solvent-Free Conditions Using a Rotary Ball Mill
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The mechanochemical technique of ball milling has been applied to the solventless and eco-friendly synthesis of chalcogenides (sulfide and selenide) of a variety of tertiary and aminophosphines. In most of the cases, the products are obtained in almost quantitative yields with high purity by applying a simple workup procedure without using chromatographic techniques or any other purification methods. The scope of this methodology was explored by using a range of phosphines (mono, di and tetra) to synthesize partial as well as mixed chalcogenides. The use of almost equimolar amounts of starting materials and the absence of any byproducts significantly simplifies the product isolation compared with the standard solution state reactions, thus providing a highly atom economic (100 %) method with an ideal E-factor (E = 0). The solid-state reactions were monitored by 31P{1H} NMR spectroscopy. The structures of some of the products are also confirmed by single-crystal X-ray analyses. Although most of the reactions were carried out on ca. 100-mg scale, the scaling up of the reaction did not affect the course of the reaction.
- Kumar, Rajnish,Kumar, Saurabh,Pandey, Madhusudan K.,Kashid, Vitthalrao S.,Radhakrishna, Latchupatula,Balakrishna, Maravanji S.
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p. 1028 - 1037
(2018/02/26)
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- Assessing the Activity of Lewis Bases Organocatalysts in Halonium-Induced Carbocyclization Reactions
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Lewis bases were evaluated as catalysts for halocarbocyclization reactions of alkynylstyrenes and a cinnamylaniline derivative. Phosphines and phosphorus chalcogenides exhibited high activity for the conversion of alkynylstyrenes in the presence of N -halosuccinimides with up to a 30-fold increase of the initial reaction rate with respect to the background reaction. Phosphorus sulfides and selenides showed the best catalytic activity for the iodocarbocyclization of a cinnamylaniline derivative in the presence of diiodohydantoin. An asymmetric variant of the iodocarbocyclization reaction of an alkynylstyrene using a chiral phosphorus selenide resulted in a modest enantioselectivity.
- Grandclaudon, Charlotte,Ruamps, Mirko,Duboc, Rapha?l,Michelet, Véronique,Toullec, Patrick Y.
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supporting information
p. 1181 - 1186
(2018/04/16)
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- Pd-Catalyzed P–C Cross-Coupling of Aryl Bromides and Triflates with Hydroxymethylphosphine Sulfide Derivatives
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The development of a versatile process for phosphine synthesis has attracted considerable interest because organophosphines are indispensable for organic synthesis. Previously, we developed a Pd-catalyzed P–C coupling reaction for hydroxymethylphosphine s
- Ohta, Hidetoshi,Xue, Qian,Hayashi, Minoru
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supporting information
p. 735 - 738
(2018/02/21)
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- Diphosphination of Arynes with Diphosphines
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A diphosphination of arynes with diphosphines has been developed. The reaction of stable aryne precursors, 2-(trimethylsilyl)aryl triflates, with tetraaryldiphosphines proceeds in the presence of fluorine- or carbonate-based activators to deliver the corresponding diphosphinated products, sterically and electronically tuned 1,2-bis(diphenylphosphino)benzene (dppbz) derivatives, which can find wide application in transition metal catalysis and material science. Additionally, preliminary computational studies on the reaction mechanism are also reported.
- Okugawa, Yuto,Hayashi, Yoshihiro,Kawauchi, Susumu,Hirano, Koji,Miura, Masahiro
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supporting information
p. 3670 - 3673
(2018/06/26)
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- PHOSPHINE COMPOUND HAVING PERFLUORO GROUP, AND COMPLEX BETWEEN METAL AND PHOSPHINE HAVING PERFLUORO GROUP
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PROBLEM TO BE SOLVED: To provide a perfluoroalkylphosphine compound, and a complex between a metal and the perfluoroalkylphosphine. SOLUTION: A perfluoroalkylphosphine compound is a phosphine compound represented by the general formula Rf-PR1R2. In the formula, R1 and R2 are each independently a substituted or unsubstituted hydrocarbon group; Rf is a perfluorinated hydrocarbon group. Also provided is a complex between the perfluoroalkylphosphine and a phosphine coordination metal. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0293-0294
(2018/10/16)
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- METHODS OF PRODUCING PHOSPHINE COMPOUND HAVING PERFLUORO GROUP AND COMPLEX BETWEEN METAL AND PHOSPHINE HAVING PERFLUORO GROUP
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PROBLEM TO BE SOLVED: To provide methods of producing a perfluoroalkylphosphine compound improved in a phosphorus element yield and a chemical yield. SOLUTION: A method of producing a perfluoroalkylphosphine compound comprises either reacting a perfluoroalkyl iodide with, e.g., 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TMDPO) or a triarylphosphine such as triphenylphosphine, which are easily available, in the presence of a radical generator such as azobis(isobutyronitrile) or light irradiation, or reacting TMDPO or the like with perfluoroalkyl iodide in the presence of diphenylphosphine, diethylphosphine, dicyclohexylphosphine or the like. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0245-0246
(2018/10/19)
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- Catalytic Degradation of Sulfur Hexafluoride by Rhodium Complexes
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The development of a safe and efficient method for the degradation of SF6 is of current environmental interest, because SF6 is one of the most potent greenhouse gases. SF6 is thermally and chemically extremely inert, and therefore, it has been used in various industrial applications. However, this inertness results in a major challenge for its depletion. We report on a process for a catalytic degradation of SF6 in the homogeneous phase by using rhodium complexes as precatalysts. The SF6 activation reactions feature mild reaction conditions, low catalyst loadings, and a high selectivity. The employment of phosphines and hydrosilanes for scavenging the sulfur and fluorine atoms of the SF6 molecule allows the selective transformation of SF6 into nongaseous and nontoxic compounds.
- Zámostná, Lada,Braun, Thomas
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supporting information
p. 10652 - 10656
(2015/09/02)
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- Frustrated Lewis pair activation of an N-sulfinylamine: A source of sulfur monoxide
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Inter- and intramolecular P/B frustrated Lewis pairs are shown to react with an N-sulfinylamine to form PNSOB linakages. These species can be regarded as phosphinimine- borane-stabilized sulfur monoxide complexes, and indeed these species act as sources of SO, effecting the oxidation of PPh3 and delivering SO to [RhCl(PPh3)3] and an N-heterocyclic carbene.
- Longobardi, Lauren E.,Wolter, Vanessa,Stephan, Douglas W.
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supporting information
p. 809 - 812
(2015/02/05)
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- The Reaction of Bunsen's Cacodyl Disulfide, Me2As(S)-S-AsMe2, with Iodine: Preparation and Properties of Dimethylarsinosulfenyl Iodide, Me2As-S-I
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Bunsen's cacodyl disulfide, Me2As(S)-S-AsMe2 (1), reacted with iodine giving the novel dimethylarsinosulfenyl iodide, Me2As-S-I (3) although theoretical calculations indicated that the AsV compound Me2As(S)-I (4) was more stable in the gas phase. The oily product was stable neat and as a solution in CDCl3 at +4 °C and -20 °C for at least 15 d. Light, H2O, H2O2, and Zn dust, but not NaI or Ag, decomposed it. Compound 3 did not interact with Ph3N, with Ph2NH and PhNH2 it interacted but not reacted. 3 was decomposed by piperidine, with pyridine and 4-dimethylaminopyridine it interacted and produced Me2As-SS-AsMe2 (2) and I2 that formed charge transfer complexes Base·I2, whereas Et3N decomposed 3, and 3Et3N·2I2 was isolated. 3 was desulfurized by Ph3P and (Me2N)3P completely, and by (PhO)3P and (PhS)3P partially. The reactions of 3 with (Me2N)3P, (PhS)3P, and (EtO)3P were complicated. From the AsIII nucleophiles, only Ph3As was bound, while (PhS)3As reacted slowly in a complicated manner with 3. No interaction of 3 with MeOH or PhOH was observed but NaOH, Ag2O, and PhONa decomposed it. Thiophenol produced traces of Me2As-SPh (10) and sodium thiophenolate attacked mainly at AsIII of 3. Thus, externally stabilized sulfenium ions of the type Me2As-S-Nu+I- were not obtained.
- Ioannou, Panayiotis V.,Vachliotis, Dimitris G.,Chrissanthopoulos, Athanassios
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p. 1340 - 1346
(2015/06/30)
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- Difluorocarbene-Derived Trifluoromethylthiolation and [18F]Trifluoromethylthiolation of Aliphatic Electrophiles
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The first trifluoromethylthiolation and [18F]trifluoromethylthiolation of alkyl electrophiles with in situ generated difluorocarbene in the presence of elemental sulfur and external (radioactive) fluoride ion is described. This transition-metal-free approach is high yielding, compatible with a variety of functional groups, and operated under mild reaction conditions. The conceptual advantage of this exogenous-fluoride-mediated transformation enables unprecedented syntheses of [18F]CF3S-labeled molecules from most commonly used [18F]fluoride ions. The rapid radiochemical reaction time (≤1 min) and high functional-group tolerance allow access to a variety of aliphatic [18F]CF3S compounds in high yields.
- Zheng, Jian,Wang, Lu,Lin, Jin-Hong,Xiao, Ji-Chang,Liang, Steven H.
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supporting information
p. 13236 - 13240
(2015/11/09)
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- Ruthenium chalcogenonitrosyl and bridged nitrido complexes containing chelating sulfur and oxygen ligands
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Ruthenium thio- and seleno-nitrosyl complexes containing chelating sulfur and oxygen ligands have been synthesised and their de-chalcogenation reactions have been studied. The reaction of mer-[Ru(N)Cl3(AsPh3)2] with elemental sulfur and selenium in tetrahydrofuran at reflux afforded the chalcogenonitrosyl complexes mer-[Ru(NX)Cl3(AsPh3)2] [X = S (1), Se (2)]. Treatment of 1 with KN(R2PS)2 afforded trans-[Ru(NS)Cl{N(R2PS)2}2] [R = Ph (3), Pri (4), But (5)]. Alternatively, the thionitrosyl complex 5 was obtained from [Bun4N][Ru(N)Cl4] and KN(But2PS)2, presumably via sulfur atom transfer from [N(But2PS)2]- to the nitride. Reactions of 1 and 2 with NaLOEt (LOEt- = [Co(η5-C5H5){P(O)(LOEt)2}3]-) gave [Ru(NX)LOEtCl2] (X = S (8), Se (9)). Treatment of [Bun4N][Ru(N)Cl4] with KN(R2PS)2 produced RuIV-RuIV μ-nitrido complexes [Ru2(μ-N){N(R2PS)2}4Cl] [R = Ph (6), Pri (7)]. Reactions of 3 and 9 with PPh3 afforded 6 and [Ru(NPPh3)LOEtCl2], respectively. The desulfurisation of 5 with [Ni(cod)2] (cod = 1,5-cyclooctadiene) gave the mixed valance RuIII-RuIV μ-nitrido complex [Ru2(μ-N){N(But2PS)2}4] (10) that was oxidised by [Cp2Fe](PF6) to give the RuIV-RuIV complex [Ru2(μ-N){N(But2PS)2}4](PF6) ([10]PF6). The crystal structures of 1, 2, 3, 7, 9 and 10 have been determined.
- Ng, Ho-Yuen,Cheung, Wai-Man,Kwan Huang, Enrique,Wong, Kang-Long,Sung, Herman H.-Y.,Williams, Ian D.,Leung, Wa-Hung
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p. 18459 - 18468
(2015/11/09)
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- Copper-catalyzed oxidative olefination of thiols using sulfones and phosphorous ylides
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Copper-catalyzed one-pot conversion of thiols to olefins was conducted under aerobic conditions. Thiols were oxidized to generate thioaldehydes, which reacted with sulfones or phosphorous ylides to form the corresponding olefins. The formation of thiosulfonates and phosphorous sulfides confirms that these olefination protocols proceed via thioaldehyde-sulfone and thioaldehyde-ylide adducts.
- Shyam, Pranab K.,Lee, Chan,Jang, Hye-Young
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supporting information
p. 1824 - 1827
(2015/07/15)
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- Nitric oxide reactivity of [2Fe-2S] clusters leading to H2S generation
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The crosstalk between two biologically important signaling molecules, nitric oxide (NO) and hydrogen sulfide (H2S), proceeds via elusive mechanism(s). Herein we report the formation of H2S by the action of NO on synthetic [2Fe-2S] clusters when the reaction environment is capable of providing a formal H? (e-/H+). Nitrosylation of (NEt4)2[Fe2S 2(SPh)4] (1) in the presence of PhSH or tBu3PhOH results in the formation of (NEt 4)[Fe(NO)2(SPh)2] (2) and H2S with the concomitant generation of PhSSPh or tBu3PhO ?. The amount of H2S generated is dependent on the electronic environment of the [2Fe-2S] cluster as well as the type of H ? donor. Employment of clusters with electron-donating groups or H? donors from thiols leads to a larger amount of H 2S evolution. The 1/NO reaction in the presence of PhSH exhibits biphasic decay kinetics with no deuterium kinetic isotope effect upon PhSD substitution. However, the rates of decay increase significantly with the use of 4-MeO-PhSH or 4-Me-PhSH in place of PhSH. These results provide the first chemical evidence to suggest that [Fe-S] clusters are likely to be a site for the crosstalk between NO and H2S in biology.
- Tran, Camly T.,Williard, Paul G.,Kim, Eunsuk
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supporting information
p. 11874 - 11877
(2014/12/10)
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- Understanding hydrogen sulfide storage: Probing conditions for sulfide release from hydrodisulfides
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Hydrogen sulfide (H2S) is an important biological signaling agent that exerts action on numerous (patho)physiological processes. Once generated, H2S can be oxidized to generate reductant-labile sulfane sulfur pools, which include hydrodisulfides/persulfides. Despite the importance of hydrodisulfides in H2S storage and signaling, little is known about the physical properties or chemical reactivity of these compounds. We report here the synthesis, isolation, and characterization (NMR, IR, Raman, HRMS, X-ray) of a small-molecule hydrodisulfide and highlight its reactivity with reductants, nucleophiles, electrophiles, acids, and bases. Our experimental results establish that hydrodisulfides release H2S upon reduction and that deprotonation results in disproportionation to the parent thiol and S0, thus providing a mechanism for transsulfuration in the sulfane sulfur pool.
- Bailey, T. Spencer,Zakharov, Lev N.,Pluth, Michael D.
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supporting information
p. 10573 - 10576
(2014/08/18)
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- Oxo-sulfido- and oxo-selenido-molybdenum(vi) complexes possessing a dithiolene ligand related to the active sites of hydroxylases of molybdoenzymes: Low temperature preparation and characterisation
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Oxo-sulfido- and oxo-selenido-molybdenum(vi) complexes with an ene-1,2-dithiolate ligand are generated as models of the active sites of molybdenum hydroxylases. The sulfide and selenide groups are highly reactive toward triphenylphosphine in the order of Se > S.
- Sugimoto, Hideki,Tatemoto, Susumu,Toyota, Kazuo,Ashikari, Kenji,Kubo, Minoru,Ogura, Takashi,Itoh, Shinobu
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supporting information
p. 4358 - 4360
(2013/06/05)
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- Synthesis of phosphorus(V)-stabilized geminal dianions. the cases of mixed P=X/PBH3 (X = S, O) and P=S/SiMe3 derivatives
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The monodeprotonation of [CH2(PPh2BH 3)(PPh2=E)] (E = S (6), O (7)) afforded [CH(PPh 2BH3)(PPh2=E)]- (E = S (6 -), O (7-)), whose structures were confirmed by X-ray crystallography. The kinetics of the second deprotonation appeared to be crucial in efficient synthesis of the corresponding dianions. Thus, the double deprotonation of 6 only led to 62-; the analogous reaction with 7 was slower and resulted only in the partial formation of 72-. Double deprotonation of the compound [CH2(SiMe3)(PPh 2=S)] (8) also resulted in the partial formation of [C(SiMe 3)(PPh2=S)]2- (82-), whose structure was confirmed by X-ray crystallography. The rare monomeric Mg carbene compound [MgC(PPh2BH3)(PPh2=S)] (9) was obtained by the reaction of 6 with Mg(nBu)2. The X-ray structure of 9 is presented.
- Heuclin, Hadrien,Fustier-Boutignon, Marie,Ho, Samuel Ying-Fu,Goff, Xavier-Frederic Le,Carenco, Sophie,So, Cheuk-Wai,Mezailles, Nicolas
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p. 498 - 508
(2013/03/14)
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- Pd-catalyzed P-C cross-coupling reactions for versatile triarylphosphine synthesis
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Practical and versatile syntheses of tertiary phosphine derivatives have been achieved by palladium-catalyzed deformylative P-C cross-coupling reactions of hydroxymethylphosphine derivatives. Sequential couplings of orthogonally protected precursors provide a simple and practical route toward a variety of tertiary phosphine derivatives having aryl substituents in any combination.
- Hayashi, Minoru,Matsuura, Takashi,Tanaka, Ippei,Ohta, Hidetoshi,Watanabe, Yutaka
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supporting information
p. 628 - 631
(2013/04/11)
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- Studies on iodination reactions of phosphiniminocyclotrithiazenes
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Iodination reactions of various phosphiniminocyclotrithiazenes [R 3PNS3N3; R = (i) phenyl-, (ii) morpholino-, and (iii) p-chlorophenyl-] have been studied under different experimental conditions. Iodination of Ph3PNS3N3 yields interesting products such as [(Ph3PN)2S3N 3]I3, ((Ph3PN)3S)2I 4, (Ph3PNH2)I3, ((Ph 3PSI2)2I2, and [(Ph 3PN)3SO]2I6 depending on the experimental conditions. All the products have been isolated and characterized by the spectroscopic and analytical techniques. Copyright Taylor & Francis Group, LLC.
- Sivaramakrishna, Akella,Swarnalatha,Sudheendra Rao
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p. 1349 - 1354
(2013/09/23)
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- Room-temperature carbon-sulfur bond formation from Ni(II) σ-aryl complex via cleavage of the S-S bond of disulfide moieties
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The formation of ArSY (Y: C(= S)NMe2, Ph, P(= O)(OEt) 2) by reductive elimination from σ-aryl complexes (M(PPh 3)2PhBr, M = Ni, Pd), associated with disulfides (YS-SY, Y: C(=S)NMe2 (1), Ph (2), P(=O)(OEt)2 (3)), at ambient temperature, has been investigated. Various mechanistic features of disulfide bond (S-S) cleavage have been elucidated using disulfide 1 by 31P NMR spectroscopy and matrix-assisted laser desorption/ionization-time of flight mass spectrometric investigations. Based upon the results of nucleophilic cleavage of the S-S bond by PPh3, studies of the reductive elimination process show that when M(PPh3)2PhBr is mixed with disulfide 1, competitive reactions occur between the PPh3 ligand, disulfide 1 and a trace amount of water, leading to low C-S coupling yields; an oxidation reaction of PPh3 with disulfide and water occur prior to C-S cross-coupling, and phosphonium ion intermediates are likely involved. However, when the disulfide 1 is pretreated with PPh3, the Ni(II) σ-aryl complex affords the C-S coupling product nearly quantitatively at room temperature. The pretreatment method is also effective for the coupling reaction of disulfide 2 and Ni(II) σ-aryl complex. The difference between Ni(II) and Pd(II) σ-aryl complexes on C-S bond formation by reductive elimination can be explained by the affinity of metal for the thiolate ligands derived from the cleaved disulfide. Copyright 2013 John Wiley & Sons, Ltd. The formation of ArSY (Y: C(= S)NMe2, Ph, P(= O)(OEt)2) by reductive elimination from σ-aryl complexes (M(PPh3)2PhBr, M = Ni, Pd) at ambient temperature, has been investigated, a result that shows an effective C-S cross-coupling reaction. Copyright
- Okamoto, Ken,Housekeeper, Jeremy B.,Luscombe, Christine K.
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p. 639 - 643
(2013/11/19)
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- Mechanism of sulfur transfer from 1,2,4-dithiazolidine-3,5-diones to triphenylphosphines
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The mechanism of sulfurization of substituted triphenylphosphines with 4-(3- and 4-substituted)-1,2,4-dithiazolidine-3,5-diones in acetonitrile, dichloromethane, tetrahydrofuran and toluene at 25°C was studied. The reaction pathway involves rate-limiting initial nucleophilic attack of the phosphorus at sulfur followed by fast decomposition of the phosphonium intermediate to the corresponding phosphine sulfide, phenylisocyanate and carbonylsulfide. From the Hammett correlations and from the solvent dependency, it was concluded that the transition-state structure is very polar and resembles the zwitter-ionic intermediate. The extent of P-S bond formation and S-S bond cleavage is very similar in the solvents series, but the latter gradually decreases with the decreasing polarity of the solvent. Copyright 2013 John Wiley & Sons, Ltd. The mechanism of sulfurization of substituted triphenylphosphines with 4-(3- and 4-substituted)-1,2,4-dithiazolidine-3,5- diones in acetonitrile, dichloromethane, tetrahydrofuran and toluene at 25°C was studied. The reaction pathway involves rate-limiting initial nucleophilic attack of the phosphorus at sulfur followed by fast decomposition of the phosphonium intermediate to the corresponding phosphine sulfide, phenylisocyanate and carbonylsulfide. The transition-state structure is very polar and resembles the zwitter-ionic phosphonium intermediate. Copyright
- Ponomarov, Oleksandr,Padelkova, Zdenka,Hanusek, Jiri
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supporting information
p. 560 - 564
(2013/07/26)
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- Synthetic applications of 3H-1,2,4-dithiazoles: Structure and reactivity studies
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Synthetic applications of 3H-1,2,4-dithiazoles have been studied extensively. The facile synthesis of hitherto unknown 3H-1,2,4-dithiazole S-oxides was realized by the mCPBA oxidation of 3H-1,2,4-dithiazoles. The structural information of the 1,2,4-dichalcogenazole ring system was revealed by the ORTEP analysis of 3-tert-butyl-5-4-chloro-phenyl-3H-1,2,4-dithiazole S-oxide. The reactivities of 3H-1,2,4-dithiazoles are also discussed.
- Islam, Md. Rafiqul,Takikawa, Yuji,Lim, Kwon Taek
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scheme or table
p. 154 - 159
(2012/07/01)
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- Rhodium-catalyzed synthesis of diaryl sulfides using aryl fluorides and sulfur/organopolysulfides
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Substituted pentafluorobenzenes react with sulfur to give bis(4-substituted 2,3,5,6-tetrafluorophenyl) sulfides in the presence of RhH(PPh 3)4, 1,2-bis(diphenylphosphino)benzene (dppBz), and tributylsilane. The reaction proceeds efficiently between room temperature and 80 °C. A comparative study of the reactivities of an organic trisulfide and a tetrasulfide showed notable substrate specificity. Di-tert-butyl tetrasulfide reacted with reactive aryl monofluorides and substituted pentafluorobenzenes. Di-tert-butyl trisulfide reacted with aryl monofluorides. The reactivity was explained on the basis of the difference in S-S bond energy.
- Arisawa, Mieko,Ichikawa, Takuya,Yamaguchi, Masahiko
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p. 5318 - 5321
(2013/01/15)
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- On the reaction of triphenylphosphane with thionyl chloride
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Triphenylphosphine reacts with thionyl chloride to give [Ph 3PCl]Cl, Ph3PO and Ph3PS the formation of the anions S(O)Cl and SCl being discussed; the crystal structure of [Ph 3PCl]Cl·S(O)Cl2 is reporte
- Klein, Hans-Friedrich,Kuhn, Annette,Kuhn, Norbert,Laufer, Stefan,Stroebele, Markus
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p. 1784 - 1786
(2013/01/14)
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- Reactivity of 3H-1,2,4-dithiazole-3-thiones and 3H-1,2-dithiole-3-thiones as sulfurizing agents for oligonucleotide synthesis
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The reactivity of 5-amino-3H-1,2,4-dithiazole-3-thiones substituted at their amino group and 5-amino-3H-1,2-dithiole-3-thiones substituted at their amino group and C4 toward compounds containing P(III) atoms has been studied. N,N-Disubstituted-N′-(3-thioxo-3H-1,2,4-dithiazol-5-yl)methanimidamides were selected as novel efficient sulfur transfer reagents suitable for DNA and RNA synthesis.
- Guzaev, Andrei P.
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body text
p. 434 - 437
(2011/02/28)
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- Kinetics and mechanism of gas-phase pyrolysis of ylides. Part 3. 1 Thermal reactivity of α-carbonyl- and thiocarbonyl-stabilized methylenetriphenylphosphoranes
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Fourteen ketone/thione-stabilized triphenylphosphonium methylides were subjected to conventional gas-phase and flash vacuum pyrolysis (FVP). The kinetics of the first-order thermal gas-phase reactions of all these compounds were investigated over 360-653K temperature range. The values of the Arrhenius logA and energy of activation of these ylides averaged 11.52±0.34s -1 and 133.20±3.14kJmol-1, respectively. The products of sealed-tube (static) and FVP were analyzed and compared. A mechanism is proposed to account for the products of reaction. The rate constants [k (s-1)] of the substrates at 500K were calculated and used to substantiate the proposed mechanism of pyrolysis, and to rationalize the thermal gas-phase reactivities of the ylides under study.
- Al-Bashir, Rasha F.,Al-Awadi, Nouria A.,El-Dusouqui, Osman M. E.
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scheme or table
p. 311 - 319
(2012/04/17)
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- Sulfur monoxide transfer from peri -substituted trisulfide-2-oxides to dienes: Substituent effects, mechanistic studies and application in thiophene synthesis
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Three peri-substituted trisulfide-2-oxides are prepared by treatment of 1,8-naphthalene dithiols with thionyl chloride and pyridine. The 1,2,3-trithiane-2-oxide ring adopts a sofa conformation in the solid state, with a pseudoaxial oxygen and evidence of ring strain (peri-interaction). Heating the trisulfide-2-oxides in the presence of a diene results in formal sulfur monoxide (SO) transfer to form unsaturated cyclic sulfoxides, along with a recyclable 1,8-naphthalene disulfide. The presence of o-methoxy or o-tert-butyl substituents on the naphthalene ring lowers the temperature and increases the rate at which SO transfer occurs. Trapping experiments and kinetic studies are consistent with the generation of triplet SO, followed by in situ trapping by diene. Transfer of SO also occurs upon irradiation at room temperature, but yields of sulfoxide are lower. Dehydration of the sulfoxides under Pummerer conditions gives thiophenes, including the naturally occurring thioperillene. Two dienes form thiophenes directly under the SO transfer conditions. The methodology is applied in a formal synthesis of the antiplatelet medication Plavix.
- Grainger, Richard S.,Patel, Bhaven,Kariuki, Benson M.,Male, Louise,Spencer, Neil
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supporting information; experimental part
p. 5843 - 5852
(2011/06/22)
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- Preparative and mechanistic studies toward the rational development of catalytic, enantioselective selenoetherification reactions
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A systematic investigation into the Lewis base catalyzed, asymmetric, intramolecular selenoetherification of olefins is described. A critical challenge for the development of this process was the identification and suppression of racemization pathways available to arylseleniranium ion intermediates. This report details a thorough study of the influences of the steric and electronic modulation of the arylselenenyl group on the configurational stability of enantioenriched seleniranium ions. These studies show that the 2-nitrophenyl group attached to the selenium atom significantly attenuates the racemization of seleniranium ions. A variety of achiral Lewis bases catalyze the intramolecular selenoetherification of alkenes using N-(2-nitrophenylselenenyl)succinimide as the electrophile along with a Bronsted acid. Preliminary mechanistic studies suggest the intermediacy of ionic Lewis base-selenium(II) adducts. Most importantly, a broad survey of chiral Lewis bases revealed that 1,1′-binaphthalene-2,2′-diamine (BINAM)-derived thiophosphoramides catalyze the cyclization of unsaturated alcohols in the presence of N-(2-nitrophenylselenenyl)succinimide and methanesulfonic acid. A variety of cyclic seleno ethers were produced in good chemical yields and in moderate to good enantioselectivities, which constitutes the first catalytic, enantioselective selenofunctionalization of unactivated olefins.
- Denmark, Scott E.,Kalyani, Dipannita,Collins, William R.
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supporting information; experimental part
p. 15752 - 15765
(2011/02/22)
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- X-ray crystal structures of ethoxycarbonyl-, diethyl-2-triphenyl- λ5-phosphoranylidene-N-phenylimide derivatives
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Phenylisothiocyanate reacts with ethyltriphenylphosphanylideneacetate at room temperature to yield 2-(ethoxycarbonyl)-2-(triphenyl-λ5- phosphanylidene)-N'-phenylethane thioimidic acid and diethyl-2-(triphenyl- λ5-phosphanylidene)-3-(phenylimlno)pentanedioate. The formation of phosphoranes are explained according to mechanism of the Wittig type reaction. The X-ray analysis structures of phosphorane adducts were studied.
- Arsanious, Mona H. N.
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experimental part
p. 710 - 713
(2011/04/24)
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- Mechanism of catalytic chalcogen atom replacement of phosphine chalcogenides and separation of the intermediate phosphine
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The reaction mechanism of the chalcogen atom replacement of phosphine chalcogenides has been revealed to be dissociative from a kinetic investigation for the reaction of phosphine selenide with sulfur. The dissociation is enthalpically promoted by the catalysis of Pd0. For a bidentate phosphine chalcogenide, the intermediate phosphine was separated as the Pd II complex by the catalysis and oxidative addition of Pd0 complex. The novel catalytic replacement and dissociation of chalcogen atom are applicable to regeneration of phosphines from their oxides via the phosphine sulfides. Copyright
- Aizawa, Sen-Ichi,Majumder, Arpi,Maeda, Daisuke,Kitamura, Akina
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body text
p. 18 - 19
(2009/12/02)
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- Thermal rearrangement of thiocarbonyl-stabilised triphenylphosphonium ylides leading to (Z)-1-diphenylphosphino-2-phenylsulfenylalkenes
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While thermolysis of thiocarbonyl-stabilised phosphonium ylides generally results in extrusion of Ph3PS to give alkynes, those with a PCH function instead undergo a novel P to S transfer of a phenyl group to give (Z)-configured 1-phosphino-2-su
- Alan Aitken,Dawson, Graham,Keddie, Neil S.,Kraus, Helmut,Slawin, Alexandra M. Z.,Wheatley, Joanne,Woollins, J. Derek
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body text
p. 7381 - 7383
(2010/06/13)
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- REACTIONS OF ISOTOPICALLY ENRICHED ELEMENTS
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Reactions of isotopically enriched samples of elements selected from phosphorus, sulfur, selenium and/or tellurium involving the addition of atoms of the isotope to organic or inorganic molecules comprising use of an ionic liquid as a reaction medium.
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Page/Page column 18
(2008/12/08)
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- Copper(I)/S8 reversible reactions leading to an end-on bound dicopper(II) disulfide complex: Nucleophilic reactivity and analogies to copper-dioxygen chemistry
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Elemental sulfur (S8) reacts reversibly with the copper(I) complex [(TMPA′)CuI]+ (1), where TMPA′ is a TMPA (tris(2-pyridylmethyl)amine) analogue with a 6-CH2OCH 3 substituent on one pyridyl ligand arm, affording a spectroscopically pure end-on bound disulfido-dicopper(II) complex [{(TMPA′)CuII}2(μ-1,2-S2 2-)]2+ (2) {ν(S-S) = 492 cm-1; ν(Cu-S)sym = 309 cm-1}; by contrast, [(TMPA)Cu I(CH3CN)]+ (3)/S8 chemistry produces an equilibrium mixture of at least three complexes. The reaction of excess PPh3 with 2 leads to formal "release" of zerovalent sulfur and reduction of copper ion to give the corresponding complex [(TMPA′)-CuI(PPh3)]+ (11) along with S=PPh3 as products. Dioxygen displaces the disulfur moiety from 2 to produce the end-on Cu2O2 complex, [{(TMPA′)Cu II}2(μ-1,2-O22-)]2+ (9). Addition of the tetradentate ligand TMPA to 2 generates the apparently more thermodynamically stable [{(TMPA)CuII}2(μ-1,2-S 22-)]2+ (4) and expected mixture of other species. Bubbling 2 with CO leads to the formation of the carbonyl adduct [(TMPA′)CuI-(CO)]+ (8). Carbonylation/sulfur- release/CO-removal cycles can be repeated several times. Sulfur atom transfer from 2 also occurs in a near quantitative manner when it is treated with 2,6-dimethylphenyl isocyanide (ArNC), leading to the corresponding isothiocyanate (ArNCS) and [(TMPA′)CuI(CNAr)]+ (12). Complex 2 readily reacts with PhCH2Br: [{(TMPA′)Cu II}2(μ-1,2-S22-)]2+ (2) + 2 PhCH2Br → [{(TMPA′)-CuII(Br)} 2]2+ (6) + PhCH2SSCH2Ph. The unprecedented substrate reactivity studies reveal that end-on bound μ-1,2-disulfide-dicopper(II) complex 2 provides a nucleophilic S 22- moiety, in striking contrast to the electrophilic behavior of a recently described side-on bound μ-η2: η2-disulfido-dicopper(II) complex, [{(N3)Cu II}2(μ-η2:η2-S 22-)]2+ (5) with tridentate N3 ligand. The investigation thus reveals striking analogies of copper/sulfur and copper/dioxygen chemistries, with regard to structure type formation and specific substrate reactivity patterns.
- Maiti, Debabrata,Woertink, Julia S.,Vance, Michael A.,Milligan, Ashley E.,Narducci Sarjeant, Amy A.,Solomon, Edward I.,Karlin, Kenneth D.
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p. 8882 - 8892
(2008/02/09)
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- Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride)
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Contrary to a previous report, the sulfurisation of phosphorus(iii) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett ρ-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are ～ -1.0. The entropies of activation are very negative (-114 ± 15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of ΔS ≠ and ρ values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations. The Royal Society of Chemistry 2007.
- Hanusek, Jiri,Russell, Mark A.,Laws, Andrew P.,Jansa, Petr,Atherton, John H.,Fettes, Kevin,Page, Michael I.
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p. 478 - 484
(2008/03/27)
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- Kinetic and mechanistic study on the thermal reactivity of stabilized phosphorus ylides, part 3: [(Acetyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and [(alkoxy-carbonyl) (arylcarbamoyl)-methylene] triphenylphosphoranes and their thiocarbamoyl analogues
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A series of five [(acety])(arylcarbabmoyl)methylene]triphenyl-phosphoranes 1a-e and their thiocarbamoyl analogues 2a-e, |(alkoxycarbonyl)(arylcarbamoyl) methylene]triphenylphosphoranes 3a-e and thiocarbamoyl analogues 4a-e were prepared and fully characterized. All ylides are found under conditions of flash vacuum pyrolysis to fragment giving arylisocyanate or isothiocyanate and acetyl ylides or alkoxy ylides which undergo thermal extrusion of Ph3PO. A kinetic study shows that these reactions are unimolecular and are of first-order nature with no significant substituent effect. The thiocarbamoyl ylides 2 react from 4.6 to 42 times faster than their carbamoyl ylides 1, while the thiocarbamoyl ylides 4 react from 6.6 to 20.9 times faster than their carbamoyl ylides 3.
- Aitken, R. Alan,Al-Awadi, Nouria A.,Dawson, Graham,El-Dusouqui, Osman,Kaul, Kamini,Kumar, Ajith
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- REACTIONS OF GROUP 16 ELEMENTS
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Reactions of Group 16 elements involving the addition of atoms such as sulfur, selenium or tellurium to organic or inorganic molecules comprising use of an ionic liquid as a reaction medium.
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Page/Page column 16
(2008/06/13)
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- Synthesis, thermal reactivity, and kinetics of stabilized phosphorus ylides, part 2: [(Arylcarbamoyl) (cyano)-methylene] triphenylphos-phoranes and their thiocarbamoyl analogues
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A series of five cyano(arylcarbamoyl) phosphorus ylides 2 and five cyano-(arylthiocarbamoyl) phosphorus ylides 3 are prepared and fully characterized. Pyrolytic reaction products of a representative example of each type obtained by flash vacuum pyrolysis technique show that they undergo thermal extrusion of Ph3PO or Ph3PS. Kinetic study of the gas-phase pyrolysis of each ylide by static method shows that these reactions are unimolecular and first order with no significant substituent effect, but the thiocarbamoyl ylides 3 react 40-65 times more rapidly than their carbamoyl analogues 2.
- Aitken, R. Alan,Al-Awadi, Nouria A.,El-Dusouqui, Osman M.E.,Farrell, Dorcas M.M.,Kumar, Ajith
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p. 496 - 502
(2008/02/09)
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- Synthesis of 1,4-dithiins from pentathiepins
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Fused aromatic and heterocyclic 1,2,3,4,5-pentathiepins react with triphenylphosphine and alkynes bearing electron-withdrawing groups to give the corresponding 1,4-dithiins in high yields. Unsymmetrical alkynes add regioselectively to afford products in agreement with the electron distribution in a proposed reaction intermediate. A mechanism for these reactions is proposed.
- Amelichev, Stanislav A.,Konstantinova, Lidia S.,Obruchnikova, Natalia V.,Rakitin, Oleg A.,Rees, Charles W.
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p. 4529 - 4532
(2007/10/03)
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- Radical phosphination of organic halides and alkyl imidazole-1- carbothioates
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Taking advantage of a radical-based methodology, mild and chemoselective phosphination reactions of organic halide and alkyl imidazole-1-carbothioates have been developed. The mild reaction conditions allow labile functional groups to survive during the reaction. Copyright
- Sato, Akinori,Yorimitsu, Hideki,Oshima, Koichiro
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p. 4240 - 4241
(2007/10/03)
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