110-51-0Relevant articles and documents
Substitution of the laser borane: Anti -B18H22 with pyridine: A structural and photophysical study of some unusually structured macropolyhedral boron hydrides
Londesborough, Michael G. S.,Dolansky, Ji?í,Jelínek, Tomá?,Kennedy, John D.,Císa?ová, Ivana,Kennedy, Robert D.,Roca-Sanjuán, Daniel,Francés-Monerris, Antonio,Lang, Kamil,Clegg, William
, p. 1709 - 1725 (2018)
Reaction of anti-B18H221 with pyridine in neutral solvents gives sparingly soluble B16H18-3′,8′-Py23a as the major product (ca. 53%) and B18H20-6′,9′-Py22 (ca. 15%) as the minor product, with small quantities of B18H20-8′-Py 4 (ca. 1%) also being formed. The three new compounds 2, 3a and 4 are characterized by single-crystal X-ray diffraction analyses and by multinuclear multiple-resonance NMR spectroscopy. Compound 2 is of ten-vertex nido:ten-vertex arachno two-atoms-in-common architecture, long postulated for a species with borons-only cluster constitution, but previously elusive. Compound 3a is of unprecedented ten-vertex nido:eight-vertex arachno two-atoms-in-common architecture. The single-crystal X-ray diffraction analysis for the picoline derivative B16H18(NC5H4Me)23b, similarly obtained, is also presented. B18H20Py 4 is also previously unreported but is of known ten-vertex nido:ten-vertex nido two-atoms-in-common architecture of anti configuration, but now with the pyridine ligand positioned differently to other reported examples of B18H20L compounds. Factors behind the remarkably low solubility of 3a and 3b are elucidated in terms of electrostatic potential (ESP) calculations, polarity, and van der Waals complementarities. In view of contemporary developing high interest in the fluorescent properties of macropolyhedral boron-containing species, a detailed assessment of the photophysical characteristics of 3a and 4 is also presented. In contrast to the thermochromic fluorescence of 2 (from 620 nm brick-red at room temperature to 585 nm yellow at 8 K, quantum yield 0.15), compound 3a is only weakly phosphorescent in the yellow region (590 nm, quantum yield 0.01), whereas compound 4 exhibits no luminescence. The far more photoactive nature of compound 2 is associated with S1 excited-state minima structures that differ from each other only by the relative rotational positions of the pyridine substituents on its disubstituted ten-vertex {arachno-B10Py2}-subcluster. The wavelength and relative intensity of fluorescence from these structures depends on the rotational positions of the pyridine ligands, which in turn are influenced by temperature and/or rotational inhibition in the solid-state.
Reactions of the Octahydrotriborate(1-) Anion, -, with Some Complexes of Cobalt(I), Cobalt(II), Rhodium(I), and Iridium(I), and the Characterization of the 'Borallyl' Complex III(η3-B3H7)(CO)H(PPh3)2>
Greenwood, Norman N.,Kennedy, John D.,Reed, David
, p. 196 - 200 (1980)
The octahydrotriborate(1-) anion, -, reacts with amine and tertiary phosphine complexes of cobalt(I) and cobalt(II) halides to give arachno-triborane-ligand adducts, B3H7L, together with B2H4L2 and BH3L (where L = pyridine or tertiary phosphine).A similar reaction occurs with trans-I(CO)Cl(PPh3)2> and with I(CO)Cl(PPh3)2>.The latter complex also yields the novel 'borallyl' compound III(η3-B3H7)(CO)H(PPh3)2> which may also be described as a nido-iridatetraborane, .The spectroscopic properties and structure of this compound are discussed.The - ion does not react with I(CO)(dppe)2>+ but I(dppe)2>+ is converted into IIIH2(dppe)2>+ (dppe = Ph2PCH2CH2PPh2).
Chemistry of boranes. XV. Synthesis of diborane from boric oxide
Ford,Kalb,Mcclelland,Muetterties
, p. 1032 - 1035 (1964)
A direct synthesis of diborane from boric oxide has been achieved by hydrogenation of the oxide in the presence of aluminum and aluminum trichloride. Very pure diborane is obtained from this reaction in 40-50% conversions at temperatures above 150° and hydrogen pressures of 750 atm. This hydrogenation is believed to proceed through an aluminum chlorohydride intermediate. Amine boranes, aminoboranes, and borazines were obtained directly from boric oxide when the hydrogenation was effected in the presence of secondary or tertiary alkylamines.
Crown-ether-catalysed synthesis of amine borane and amine trideuterioborane adducts from NaBH4-NaBD4 in ether
Kampel, V.,Warshawsky, A.
, p. 15 - 18 (1994)
Amine borane and amine trideuterioborane adducts have been obtained in good yield by the crown-ether-catalysed reaction of R3N*HCl with NaBH4 and NaBD4 in ether.The absence of isotopic exchange in the reaction with NaBD4 is demonstrated by IR and 11B and
Matrix Isolation Study of the Reactions of B2H6 with Pyridine, Pyrrole, and Pyrrolidine: Spectroscopic Characterization of C4H9N*BH3 and C4H8N=BH2
Carpenter, John D.,Ault, Bruce S.
, p. 11397 - 11401 (1993)
The products of the pyrolytic reaction of B2H6 with pyrrole, pyrrolidine, and pyridine have been isolated in argon matrices at 14 K and characterized by infrared spectroscopy.For the B2H6/C4H9N system, complex formation was observed at temperatures between ambient and 200 deg C and the subsequent H2 elimination product H2B=NC4H8 at pyrolysis temperatures above 50 deg C.The B=N stretching frequency (1486 cm-1) and local density functional calculations done in upport of the experiments both support substantial double-bond character for the boron-nitrogen bond.The reaction of B2H6 with pyridine led to formation of the H3B*NC5H5 complex only, while copyrolysis of B2H6 with pyrrole led to no reaction even when a pyrolysis temperature of 380 deg C was employed.This result is best understood in terms of the role of thenitrogen lone pair in the aromaticity of the pyrrole ring.
Catalytic Reactions of Metalloporphyrins. 1. Catalytic Modifikation of Borane Reduction of Ketone with Rhodium(III) Porphyrin as Catalyst
Aoyama, Yasuhiro,Fujisawa, Takeshi,Watanabe, Takamichi,Toi, Hiroo,Ogoshi, Hisanobu
, p. 943 - 947 (1986)
(Octaethyl- or tetraphenylporphyrinato)rhodium(III) chloride shows an efficient catalysis in the aerobic reduction of ketone with NaBH4 in THF, BH4- + 2R1R2C=O + O2 ->2R1R2CHOH + BO2-.The initial step in the catalytic cycle is the rate-determining complexation of BH4- with RhIII porphyrin (RhIII + BH4- -> RhIII-BH4) followed by a rapid borane transfer from the adduct to ketone to give dialkoxyborane and hydridorhodium species (RhIII-BH4 + 2R1R2C=O -> Rh-H + HB(O-CHR1R2)2).In the subsequent step, the Rh-H species undergoes oxidation with O2 back to RhIII with concomitant "hydrolisis" of dialkoxyborane to alcohol (Rh-H + O2 + HB(O-CHR1R2)2 -> RhIII + 2R1R2CHOH + BO2-).Essentially, autorecycling RhIII and Rh-H act as a "borane" generator and proton source, respectively, in a catalytic manner.Furthermore, the RhIII-BH4 complex capable of transferring borane to ketone lacks what is characteristic of free borane, i.e., facile oxidation with O2 and ready hydrolysis with H2O.Thus, the present system provedes a highly efficient, catalytic modification of synthetic reactions of borane in the presence of oxygen.
Amine-boranes bearing borane-incompatible functionalities: Application to selective amine protection and surface functionalization
Veeraraghavan Ramachandran,Kulkarni, Ameya S.,Zhao, Yan,Mei, Jianguo
, p. 11885 - 11888 (2016)
The first general open-flask synthesis of amine-boranes with inexpensive and readily available reagents, such as sodium borohydride, sodium bicarbonate, water, and the desired amines is described. Even amines bearing borane-reactive functionalities, such as alkene, alkyne, hydroxyl, thiol, ester, amide, nitrile, and nitro are well tolerated. Some of these novel amine-boranes represent stable molecules containing potentially incompatible electrophilic and nucleophilic centers in proximity. This convenient scalable synthesis provides a novel class of organic ligands for surface functionalization, as demonstrated by the formation of self-assembled layers of thiol- and alkoxysilane-bearing amine-boranes on gold and silica surfaces, respectively.
Reactivity of Decaborane(14) with Pyridine: Synthesis and Characterization of the First 6,6-Substituted Isomer of nido-B10H14, 6,6-(C5H5N)2B10H12, and Application of (11)B-(11)B Double-Quantum NMR Spectroscopy
Cendrowski-Guillaume, Sophie M.,O'Loughlin, Jennifer L.,Pelczer, Istvan,Spencer, James T.
, p. 3935 - 3941 (1995)
In the low-temperature reaction of B10H14 with C5H5N, a new product, identified as arachno-6,6-(C5H5N)2B10H12, was formed in high yield and purity. The proposed 6,6-L2B10H12 compound represents the first known report of this decaborane substitution pattern. The formation of an asymmetric 6,6-(C5H5N)2B10H12 isomer was unexpected on the basis of literature precedent describing the synthesis and structural elucidation of numerous 6,9-L2B10H12 species (where L = Lewis base). The observed reaction sequence in the formation of the 6,6-(C5H5N)2B10H12 compound proceeded through an initially observed (H.C5H5N](1+)[B10H13](1-) intermediate. In addition to the formation of the 6,6-isomer, the synthesis of the 6,9-(C5H5N)2B10H12 isomer is also reported from the reflux of nido-B10H14 in pyridine. Refluxing the 6,6-(pyridine)2B10H12 isomer in pyridine was also found to convert this isomer into the 6,9-isomer. Both isomers were characterized by (11)B NMR, FTIR, UV-vis, mass spectroscopic, and elemental analyses. The structure of the 6,6-isomer was established by 2D (11)B-(11)B COSY NMR data and by the first application of a pure phase (11)B-(11)B 2Q correlation NMR (double-quantum) experiment to the elucidation of a borane cluster framework. This latter NMR technique was very successful ingreatly simplifying the NMR assignments of the 6,6-substituted decaborane cluster species and should be a very powerful tool in cluster structure elucidation in general.
Coordination Chemistry of Borane in Solution: Application to a STING Agonist
Lemaire, Sébastien,Zhdanko, Alexander,van der Worp, Boris A.
, (2022/04/09)
Equilibrium constants were determined for ligand exchange reactions of borane complexes with various oxygen, sulfur, nitrogen, and phosphorus nucleophiles in solution, and a binding affinity scale was built spanning a range of 12 orders of magnitude. While the Keq are minimally dependent on the solvent, the rate of ligand exchange varies significantly. The fastest and slowest rates were observed in THF and CDCl3, respectively. Moreover, the ligand exchange rate differs in a very broad range depending on stability of the starting complex. Binding of BH3 was found to be much more sensitive to steric factors than protonation. Comparing nitrogen bases having equal steric properties, a linear correlation of BH3 binding affinity vs. Br?nsted acidity was found. This correlation can be used to quickly estimate the BH3 binding affinity of a substrate if pKa is known. Kinetic studies suggest the ligand exchange to occur as a bimolecular SN2 reaction unless other nucleophilic species were present in the reaction mixture.
Activation of sodium borohydride via carbonyl reduction for the synthesis of amine- And phosphine-boranes
Hamann, Henry J.,Lin, Randy,Veeraraghavan Ramachandran, P.
supporting information, p. 16770 - 16774 (2021/12/08)
A highly versatile synthesis of amine-boranes via carbonyl reduction by sodium borohydride is described. Unlike the prior bicarbonate-mediated protocol, which proceeds via a salt metathesis reaction, the carbon dioxide-mediated synthesis proceeds via reduction to a monoformatoborohydride intermediate. This has been verified by spectroscopic analysis, and by using aldehydes and ketones as the carbonyl source for the activation of sodium borohydride. This process has been used to produce borane complexes with 1°-, 2°-, and 3°-amines, including those with borane reactive functionalities, heteroarylamines, and a series of phosphines.
