- Production and decomposition of (NH4)[BF4] and H3N-BF3
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(NH4)[BF4] is produced as single crystals during the reaction of elemental boron and NH4HF2 (B:NH4HF2 = 1:2) and NH4F (B:NH4F = 1:4), respectively, in sealed copper ampoules at 300°C. The crystal structure (baryte type, orthorhombic, Pnma, Z = 4) was redetermined at ambient temperature (a = 909.73(18), b = 569.77(10), c = 729.47(11) pm, Rall = 0.0361) and at 140 K (a = 887.3(2), b = 574.59(12), c = 717.10(12)pm, Rall = 0.0321). Isolated (NH4)+ and [BF4]- tetrahedra are the important building units. The thermal behaviour of (NH4)[BF4] was investigated under inert (Ar, N2) and reactive conditions (NH3) with the aid of DTA/TG and DSC measurements and with in-situ X-ray powder diffraction as well. Finally, (NH4)[BF4] is decomposed yielding NH3 and BF3, BN is not produced under the current conditions. Colourless single crystals of H3N-BF3 were prepared directly from the components NH3 and BF3. The crystal structure was determined anew at 293 and 170 K (orthorhombic, Pbca, Z = 8, a = 815.12(10), b = 805.91(14), c = 929.03(12) pm, Rall = 0.0367; a = 807.26(13), b = 800.48(10), c = 924.31(11)pm, Rall = 0.0292, T = 170 K). The crystal structure contains isolated molecules H3N-BF3 in staggered conformation with a B-N distance of 158 pm. The thermal behaviour of H3N-BF3 was studied likewise.
- Gbbels, Dirk,Meyer, Gerd
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- Interaction of datolite concentrate with ammonium hydrodifluoride
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The interaction of datolite concentrate with ammonium hydrodifluoride were studied. Under heating, ammonium hydrodifluoride fluorinates datolite to form complex fluoroammonium salts of boron, silicon, and impurity metals. The activation energy and rate constants were calculated for the reaction of datolite concentrate with ammonium hydrodifluoride in the range 100-150°C. The composition of the vola-tiles formed upon the heating of the fluorinated concentrate was studied, the temperature parameters of the evolution of boron and silicon to the gas phase were determined, and a process for separating these elements was proposed. Pleiades Publishing, Ltd., 2010.
- Krysenko,Medkov,Epov
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- Reductive cleavage of the N-N bond of hydrazine induced by a cationic trinuclear ruthenium hexahydride complex, [(Cp'Ru)3(μ-H) 6]X (Cp' = ν5-C5Me5; X = 1/2 SO4, BF4, PF6, BPh4) and dihydrogen
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The reaction of the monocationic triruthenium hexahydride [(Cp'Ru) 3(μ-H)6]X (1; X = 1/2 SO4, BF4, PF6, BPh4) with hydrazine leads to the formation of the mono(μ3-imido) complex (Cp'Ru)3(μ3-NH) (μ-H)3 (3) and the triruthenium pentahydride complex (Cp'Ru) 3(μ3-H)2(μ-H)3 (2). Complex 1 is in equilibrium with 2 in the presence of NH4X or N 2H5X, and complex 1 is regenerated upon treatment of 2 with such a protic salt. Complex 3 further reacts with hydrazine to yield the bis(μ3-imido) complex (Cp'Ru)3(μ3-NH) 2(μ-H) (4) as a result of cleavage of the nitrogen-nitrogen bond, which is formally catalyzed by a proton. Both 3 and 4 undergo hydrogenation to generate 2 together with ammonia. Thus, reductive cleavage of the nitrogen-nitrogen bond of hydrazine leading to ammonia is achieved by the use of the monocationic trinuclear hexahydride complex 1 and dihydrogen under conditions without any added proton source and a reducing agent.
- Nakajima, Yumiko,Inagaki, Akiko,Suzuki, Hiroharu
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- Reaction of arenediazonium tetrafluroborates with N,N-methylenediacryalmide in the presence of thiocyanate anions
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The reactions of arenediazonium tetrafluoroborates with N,N-methylenediacrylamide in H2O-DMF (1:3) and H2O-DMSO (1:4) in the presence of thiocyanate anions involve thiocyanatoarylation by one or two multiple bonds to give [(3-aryl-2-
- Grishchuk,Baranovskii,Gorbovoi,Ganushchak
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p. 957 - 960
(2007/10/03)
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- Reactions of arenediazonium tetrafluoroborates with 1,4-bis(acryloyloxy)butane in the presence of thiocyanate ion
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The first thiocyanatoarylation reaction with an unsaturated compound containing two isolated multiple bonds, 1,4-bis(acryloyloxy)butane, was effected. The reactions of 1,4-bis(acryloyloxy)butane with arenediazonium tetrafluoroborates occur in aqueous acet
- Gorbovoi,Baranovskii,Koval'skii,Grishchuk
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p. 1230 - 1232
(2007/10/03)
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- Reactions of a sulfido-bridged dinuclear molybdenum complex with nitriles and isonitriles under hydrogen: Facile C≡N bond cleavage
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The dinuclear complex [(CpMo)2(S2CH2)(μ-S)(μ-SH)] +X- (X = SO3CF3, BF4; Cp = C5H5; 1(X)) reacted with nitriles RCN under 1-2 atm of H2 at 25-50°C to form the new cationic complex [CpMo(S2CH2)(S2CR)MoCp]+ and ammonia. The reaction has been characterized for HCN as well as for a series of alkyl- and aryl-substituted nitriles. Complex 1 reacted with isonitriles (RNC) and hydrogen under similar conditions to form the cationic complex [CpMo(S2CH2)(S2CH)MoCp]+ and the primary amine RNH2. The reactions were inhibited by excess acid. In order to probe the mechanisms of these reactions, the interactions of nitriles and isonitriles with 1 in the absence and presence of a protic acid and in the absence and presence of hydrogen have been studied. In the absence of hydrogen, 1 reacted with isonitriles to form [(CpMo)2(S2CH2)(S2CNH(R))] + (2), but no reaction of 1 with nitriles was detected spectroscopically. Under similar conditions in the presence of excess protic acid, 1 reacted with n-butyl isocyanide to form [(CpMo)2(S2CH2)(μ-S)(μ-SCH=NHBu)] 2+ (4) and with acetonitrile to form [(CpMo)2(S2CH2)(μ-S)(μ-SC(CH 3)=NH2)]2+ (5). These S-H insertion products were identified by spectroscopic methods. The reaction of 4 and 5 with hydrogen appeared to involve carbon-sulfur bond hydrogenolysis; e.g., in the reaction of 5 with H2, ethylammonium ion was identified as a product. The C-N bond cleavage reactions are proposed to involve the deprotonated forms of the insertion products 4 and 5, [(CpMo)2(S2CH2)(μ-S)(μ-SCH=NBu)] + and [(CpMo)2(S2CH2)(μ-S)(μ-SC(CH 3)=NH)]+. The former complex was tentatively identified by NMR spectroscopy. Reactions of these derivatives with hydrogen are proposed to lead to intramolecular S-H insertion products [(CpMo)2(S2CH2)(S2CH(NH 2Bu))]+ (6) and [(CpMo)2(S2CH2)(S2C(CH 3)NH3)]+ (7). A precedent for this type of reaction has been characterized in a related molybdenum system. Complexes 6 and 7 are expected to eliminate BuNH2 and NH3, respectively, to form the final molybdenum products. The possible relevance of these reactions to the reductions of nitriles and isonitriles effected by the nitrogenase enzymes is discussed.
- Bernatis, Paul,Laurie,DuBois, M. Rakowski
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p. 1607 - 1617
(2008/10/08)
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