- Oxothiomolybdenum derivatives of the superlacunary crown heteropolyanion {P8W48}: Structure of [K4{Mo4O 4S4(H2O)3(OH)2} 2-(WO2)(P8W48O184)] 30- and studies in solution
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Reaction of the cyclic lacunary [H7P8W 48O184]30- anion (noted P8W 48)with the [Mo2S2O2(H2O)6]2+ oxothiocation led to two compounds, namely, [K4{Mo4O 4S4(H2O)3-(OH)2} 2(WO2)(P8W48O184)] 30- (denoted 1)and [{Mo4O4S4(H 2O)3(OH)2}2(P8W 48O184)]36-(denoted 2), which were characterized in the solid state and solution. In the solid state, the structure of [K 4{Mo4O4S4(H2O) 3(OH)2}2-(WO2)(P8W 48O184)]30- reveals the presence of two disordered {Mo4O4S4(H2O) 3(OH)2}2+ "handles" connected on both sides of the P8W48 ring. Such a disorder is consistent with the presence of two geometrical isomers where the relative disposition of the two {Mo4O4S4(H2O) 3(OH)2}2+ handles are arranged in a perpendicular or parallel mode. Such an interpretation is fully supported by 31P and 183W NMR solution studies. The relative stability of both geometrical isomers appears to be dependent upon the nature of the internal alkali cations, i.e., Na+ vs K+, and increased lability of the two {Mo4O 4S4(H2O)3(OH)2} 2+ handles, compared to the oxo analogous, was clearly identified by significant broadening of the 31P and 183W NMR lines. Solution studies carried out by UV-vis spectroscopy showed that formation of the adduct [{Mo 4O4S4(H2O)3(OH) 2}2(P8W48O184)]36-occurs in the 1.5-4.7 pH range and corresponds to a fast and quantitative condensation process. Furthermore, 31P NMR titrations in solution reveal formation of the "monohandle" derivative [{Mo4O4S 4(H2O)3(OH)2}(P8W 48O184)]38-as an intermediate prior to formation of the "bishandle" derivatives. Furthermore, the electrochemical behavior of [{Mo4O4S4(H2O)3(OH) 2}2(P8W48O184)]36-was studied in aqueous medium and compared with the parent anion P8W 48.
- Korenev, Vladimir S.,Floquet, Sebastien,Marrot, Jerome,Haouas, Mohamed,Mbomekalle, Israel-Martyr,Taulelle, Francis,Sokolov, Maxim N.,Fedin, Vladimir P.,Cadot, Emmanuel
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- A solid-state NMR and computational study of sodium and potassium tetraphenylborates:23Na and39K NMR signatures for systems containing cation-π interactions
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Sodium and potassium tetraphenylborates were examined by solid-state 23Na and 39K NMR spectroscopy. Analyses of solid-state NMR spectra obtained at 4.70, 11.75, and 19.60 T yielded the following 23Na and 39K NMR parameters: Na[BPh4], |C Q| = 1.24 ± 0.05 MHz, ηQ = 0.0 ± 0.1, δiso = -45.6 ± 0.5 ppm, and Ω = 14 ± 2 ppm; K[BPh4], |CQ| = 1.32 ± 0.05 MHz, ηQ = 0.0 ± 0.1, and δiso = -92 ± 1 ppm. In both Na[BPh4] and K[BPh4], the electric field gradient and chemical shift tensors at the metal site are axially symmetric, in agreement with the crystallographic symmetry. Extensive quantum mechanical calculations were performed for Na[BPh4] and K[BPh4] as well as for a large number of model cation-π systems containing Na+ and K + ions and common aromatic compounds. Experimental and theoretical studies confirm that a highly shielded environment at the metal cation site is a characteristic feature for cation-π interactions, making it useful as a NMR signature for identifying cation-π interactions in proteins and nucleic acids. In this study, powder X-ray diffraction spectra for Na[BPh4] and K[BPh4] were also reported.
- Wong, Alan,Whitehead, Robert D.,Gan, Zhehong,Wu, Gang
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- METHOD FOR PRODUCING BORATE SALT
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PROBLEM TO BE SOLVED: To provide a method for producing borate salt which makes it possible to obtain borate salt with different groups bound to boron atoms in high yield. SOLUTION: The present invention provides a method for producing borate salt (A) represented by general formula (1), including the steps for making a reaction occur between borate salt (B) represented by general formula (2) and organic metal compound (C) represented by general formula (3) or general formula (4). SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0099; 0105
(2018/09/02)
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- Highly nucleophilic dipropanolamine chelated boron reagents for aryl-transmetallation to iron complexes
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New aryl- and heteroarylboronate esters chelated by dipropanolamine are synthesised directly from boronic acids. The corresponding anionic borates are readily accessible by deprotonation and demonstrate an increase in hydrocarbyl nucleophilicity in comparison to other common borates. The new borates proved competent for magnesium or zinc additive-free, direct boron-to-iron hydrocarbyl transmetallations with well-defined iron(ii) (pre)catalysts. The application of the new borate reagents in representative Csp2-Csp3 cross-coupling led to almost exclusive homocoupling unless coupling is performed in the presence of a zinc additive.
- Dunsford, Jay J.,Clark, Ewan R.,Ingleson, Michael J.
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supporting information
p. 20577 - 20583
(2015/12/04)
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- Reactions of Bis(dihydrogen)hydridoiron(1+) with Alkynes
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The compounds BPh4 and BPh4 (dmpe = Me2PCH2CH2PMe2 and depe = Et2PCH2CH2PEt2) reacted with terminal alkynes R'CCH (R = Me, i-Pr or Ph) to yield a variety of structures, apparently formed in sequence, bis(alkynyl), alkynyl(vinylidene) and substituted butenynyl complexes of iron(II), which also contain bis(diphosphines).The structures of trans-BF4, trans-BF4, and have been determined and the interconversions of the complexes are discussed.
- Hughes, David L.,Jimenez-Tenorio, Manuel,Leigh, G. Jeffery,Rowley, Adrian T.
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p. 3151 - 3162
(2007/10/02)
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- Alkali metal salt solvation study in 1,1,3,3-tetramethylurea using nuclear magnetic resonance spectroscopy
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The solution behavior of a series of alkali metal tetraphenylborates, perchlorates, and iodides in 1,1,3,3-tetramethylurea (TMU) has been studied by proton nuclear magnetic resonance (NMR) spectroscopy.TMU has a simple proton NMR spectrum consisting of one singlet at 2.75 ppm.Alkali metyl tetraphenylborates and perchloates were observed to be dissociated in TMU.Sodium iodide, however, was observed to be associated in TMU.Present results are compared with those from other NMR investigations in TMU and related nonaqueous solvents.Key words: alkali metal salt solvation, tetramethylurea; nuclear magnetic resonance, solute-solvent interactions
- Ciolino, Laura Ann,Barker, Barbara Jane
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p. 2206 - 2208
(2007/10/02)
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- Electron Transfer and Ion Pairing, 7. Contact Ion Pairs of Sulfur-Containing Radical Anions
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The structurally different radical anions M(-) of peralkylated 1-sila-2,5-diazacyclopentane-3,4-dithione and of tetrakis(isopropylthio)-p-benzoquinone are generated by reduction with potassium/2.2.2-cryptand under aprotic conditions in THF solution.On addition of Li(+)B(C6H5)4(-), both form hitherto elusive sulfur-containing contact ion pairs, which are characterized by their ESR/ENDOR spectra. - Keywords: Contact Ion Pairs, ESR, ENDOR and Triple Spectra, Reduction of 1-Sila-2,5-diazacyclopentane-3,4-dithione and of Tetrakis(isopropylthio)-p-benzoquinone
- Bock, Hans,Haenel, Peter,Herrmann, H.-F.,Dieck, Heindirk tom
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p. 1240 - 1246
(2007/10/02)
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