cas 10294-34-5, Boron trichloride | Articles data

Articles about 10294-34-5Total 37 be found

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Reactions of pentaborane(9) and pentaborane derivatives
The preparations of a number of pentaborane derivatives are described and 11B and 1H nmr spectra recorded and correlated. Assessments of alternative preparative schemes are given. An extension of the apex to base rearrangement reaction to polyalkyl pentaboranes reveals the following trends: the rate of rearrangement decreases with increasing number of alkyl substituents on the pentaborane framework; the rate increases with the use of stronger and less sterically hindered bases. Mechanistic inferences are discussed.
Onak, Thomas,Dunks, Gary B.,Searcy, I. William,Spielman
p. 1465 - 1471
(1967)
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A study of boron halide-phosphorus halide complexes
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Armington,Weiner,Moates
p. 483 - 484
(1966)
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On the properties of monochlorodiborane
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Myers, Hulon W.,Putnam, Roy F.
p. 655 - 657
(1963)
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A Novel Graphite-Like Material of Composition BC3, and Nitrogen-Carbon Graphites
Interaction of benzene with boron trichloride at 800 deg C yields a graphite-like metallic solid of composition BC3, and chlorine-pyridine mixtures at 800 deg C give a nitrogen-carbon also having a graphite-like structure.
Kouvetakis, John,Kaner, Richard B.,Sattler, Margaret L.,Bartlett, Neil
p. 1758 - 1759
(1986)
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TiB2 COATINGS ON PHOSPHOR BRONZE PLATES BY CVD AND THEIR PROPERTIES.
A phosphor bronze plate was coated with a thin layer of TiB//2 from a gas mixture of TiCl//4, BCl//3, H//2 and argon at temperatures of 580-850 degree C. The oxidation and corrosion stabilities were examined. Uniform and adherent TiB//2 layers were obtained on the phosphor bronze plate in the temperature range of 600-700 degree C. The deposition rates were 1. 1 mu m H** minus **1 and 2. 2 mu m h** minus **1 at temperatures of 700 degree C and 750 degree C respectively. Tib//2-coated phosphor bronze plates were stable to oxidation at temperatures below 600 degree C and were slightly affected by 3. 2 N HNO//3 at room temperature and concentrated HCl at 60 degree C.
Motojima,Hotta
p. 327 - 333
(1988)
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[(acridine)BCl2]+: A borenium cation that is a strong boron- and carbon-based lewis acid
[(acridine)BCl2][AlCl4] was synthesized by halide abstraction from (acridine)BCl3 with AlCl3. The hydride ion affinity of the C9 position in [(acridine)BCl2]+ was calculated to be 14 kcal mol-1 greater than that at boron. [(acridine)BCl2][AlCl4] reacts with 1 equiv of acridine to form the strained boronium cation [(acridine)2BCl 2][AlCl4] and with P(mesityl)3 by photoinduced one-electron transfer to form the 9,9′-biacridane moiety by radical coupling. A stable frustrated Lewis pair (FLP) was formed on combining [(acridine)BCl2][AlCl4] and 2,4,6-tri-tert-butylpyridine (TBP), which heterolytically activated H2 at 100 C. The ultimate location of the hydride from H2 activation was the C9 position of acridine and not boron. Carbon Lewis acid based reactivity also occurred when thieno[3,2-b]thiophene was added to the [(acridine)BCl2][AlCl 4]/TBP FLP or to [(acridine)2BCl2][AlCl 4], with arylation of acridine at C9 observed for both.
Clark, Ewan R.,Ingleson, Michael J.
p. 6712 - 6717
(2013)
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Lynds,Stern
p. 5006
(1959)
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Jerumanis,S.,Lalancette,J.M.
p. 1531 - 1533
(1966)
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THERMODYNAMIC PROPERTIES OF BHCL2 FROM THE EQUILIBRATION OF BCL3-H2 MIXTURES
In the temperature range 700 to 850 C, BCl//3-H//2 mixtures give BHCl//2 and HCl as the only gaseous products. Analysis of equilibrium gas mixtures gave equilibrium constants from which the standard formation enthalpy and standard entropy of BHCl//2 were
ATTWOOD B,SHELTON RAJ
p. 131 - 134
(1970)
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Dichloroboronation of aromatic hydrocarbons. Mechanistic aspects
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Muetterties,Tebbe
p. 2663 - 2664
(1968)
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Thermodynamic properties of dichloroborane
The disproportionation reaction for HBCl2, 6HBCl2 ? 4BCl3 + B2H6, was followed spectrophotometrically in the infrared region and an equilibrium constant (Kp (298° K.) = 532 ± 15 atm.-1
Lynds, Lahmer,Bass, C. David
p. 1147 - 1149
(1964)
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A self-contained regeneration scheme for spent ammonia borane based on the catalytic hydrodechlorination of BCl3
Recycling: A self-contained procedure for the recycling of BNH-waste, based on the three major steps: polymer break-up, amine supported catalytic hydrodehalogenation of boron halogens, and the base exchange in borane amine adducts, is developed (see picture). Beyond the original task of recycling spent ammonia borane, the process provides a new means to produce borohydride species efficiently, by the direct use of molecular hydrogen. Copyright
Reller, Christian,Mertens, Florian O.R.L.
p. 11731 - 11735
(2013/01/15)

Chelate restrained boron cations for intermolecular electrophilic arene borylation
Highly electrophilic boron species that borylate arenes are generated by halide abstraction from CatBX (Cat = catecholato, C6H 4O22-, X = Cl or Br) by [Et3Si] [CbBr6] (CbBr6 = [closo-1-H-CB11H 5Br6]-). A transient [CatB][CbBr6] related species reacts as a synthetic equivalent of [CatB]+ in intermolecular electrophilic borylation, with reactions proceeding rapidly at 25 °C. The [CatB]+ moiety was shown to be strongly Lewis acidic on the basis of 1H and 31P{1H} NMR spectroscopy of the crotonaldehyde and triethylphosphine oxide adducts, respectively. Catalytic quantities of [Et3Si][CbBr6] and CatBX were effective for the high-yielding borylation of arenes by CatBH in a highly atom efficient cycle with H2 the only byproduct. Successful catalysis was dependent on the robust [CbBr6]- anion and the use of electrophile-resistant borane sources
Del Grosso, Alessandro,Pritchard, Robin G.,Muryn, Chris A.,Ingleson, Michael J.
p. 241 - 249
(2010/04/04)

Silicon-boron-carbon-nitrogen ceramics and precursor compounds, methods for the production and use thereof
The present invention relates to novel processes for preparing borylsilylamines, novel amines, novel borosilazane compounds, novel oligoborosilazane or polyborosilazane compounds which have the structural feature Si—N—B, ceramic material and methods of producing and using them.
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(2010/02/05)

Introduction of ClO4-, NO3-, and C(NO2)3- anions into the coordination sphere of boron by directly reacting salts with boron halides
We established that salts of ClO4-, NO 3-, and C(NO2)3- anions (Y) directly react with boron halides BX3 (X = F, Cl, Br) to yield [X3BA]- complex anions. The [X3BOClO 3]- (X = F, Cl, Br) anions are stable in a CHCl 3 solution. They are isolated as salts of R4N+ cations in the solid state. Their IR and 11B NMR spectra are characterized. The decomposition of R4N[X3BOClO 3] salts starts with the elimination of part of the boron halide and ends by the irreversible decomposition of a solid residue at above 200°C. The enthalpies of dissociation of chloroperchloratoborates R 4N[Cl3BOClO3](cr) - R 4NClO4(cr) + BCl3(gas) are naturally positioned between the enthalpies of dissociation for salts of BCl4- and [B(C1O4)4]-. The donating bond energy of ClO4- to a boron atom is similar to the energy of an ordinary chemical bond. The BCl3 reactions with nitrates and nitroform salts yield low-stability anions [Cl3BONO2] - and [Cl3BC(NO2)3]-. These anions are decomposed directly in the reaction medium (CHCl3). The initial stage is a disproportionation reaction to yield the end-members of the anion series: BCl4- and BF4-. (C2H5)4N[B(NO3)4] was isolated and identified in the reaction of BCl3 with (C 2H5)4N[B(NO3)4]. The possibility of {B[C(NO2)3]4}- formation was proven by counter synthesis: the complex salt (CH 3)4N{B[C(NO2)3]4 was prepared by reacting (CH3)4NBCl4 with excess AgC(NO2)3 at -50°C. The compound is unstable; it decomposes at -30°C with vigorous gas evolution.
Titova
p. 1121 - 1129
(2008/10/08)

Studies on BCl and on the exchange reaction of BCl3 with polyboron flourides
Gaseous BCl has been prepared at low pressure by reaction of BCl3 with boron at 2000 °C or by decomposition of B2Cl4 using either an electric discharge or using flash thermolysis at 1150 °C, and then condensed at - 196 °C. Reasons are discussed why each method gives BCl capable of generating (Cl2B)3BCO when the condensate at - 196 °C is treated with CO, but B4Cl4 is only formed from BCl prepared from B2Cl4. The stepwise conversion of (F2B)3BCO to (Cl2B)3BCO by treatment with BCl3 has been followed by 11B NMR spectroscopy. Evidence from mass spectrometry and 11B NMR spectroscopy suggests that reaction of polyboron fluorides, particularly B8F12 and B10F12, with BCl3 yields a new form of B9Cl9 of, as yet, unknown structure which converts slowly to closo-B9Cl9 or closo-B8Cl8 depending on the solvent.
Pardoe, Jennifer A.J.,Norman, Nicholas C.,Timms, Peter L.
p. 543 - 548
(2008/10/08)

Synthesis of halogenated polyhedral phosphaboranes. Crystal structure of closo-1,7-P2B10Cl10
The 12-vertex closo-phosphaborane 1,7-P2B10Cl10 (1) has been prepared in low yield from the pyrolysis reaction of B2Cl4 with PCl3 at temperatures above 400 °C. A single-crystal X-ray structure determination of 1 (monoclinic space group P21/n with a = 9.239(2) A, b = 16.786(3) A, c = 15.739(3) A, β = 93.25(3)°, and Z = 4) confirmed that, consistent with its 26 skeletal electron count, the phosphaborane adopts a distorted icosahedral structure with the phosphorus atoms in the 1,7-positions. Crystals of 1 contain toluene in a 1:1 molar ratio embedded between each P atom of neighboring cluster molecules. Alteration of the pyrolytic conditions resulted in the formation of the phosphaboranes P4B8Cl6 (2) and P2B8Cl8 (3), which were characterized spectroscopically. Copyrolysis of B2Cl4 with a mixture of PCl3 and AsCl3 at 450 °C generated the six-vertex arsaphosphaborane AsPB4Cl4 (4) and traces of the icosahedral arsaphosphaborane AsPB10Cl10. These compounds are examples of heteroboranes which contain two different group-15 atoms within a single molecule.
Keller, Willi,Sawitzki, Gisela,Haubold, Wolfgang
p. 1282 - 1287
(2008/10/08)

Preparation, Structure and Reactivity of 2-Chloro-, 2-Fluoro- and 2-Iodo-2,3-dihydro-1H-1,3,2-diazaboroles
A series of differently substituted 2-chloro-, 2-fluoro- and 2-iodo-2,3-dihydro-1H-1,3,2-diazaboroles have been prepared by various methods. 1,3-Di-tert-butyl-2-fruoro-2,3-dihydro1H-1,3,2-diazaborole (3a), 1,3-di-tert-butyl-2-chloro-2,3-dihydro-1H-1,3,2-diazaborole (5a), 1,3-bis(2,6-dimethyl-phenyl)-2-chloro-2,3-dihydro-1H-1,3,2-diazaborole (5b), 2-chloro-4,5-dimethyl-1,3-dineopentyl-2,3-dihydro-1H-1,3,2-diazaborole (Sc), and 1,3-di-tert-butyl-2-iodo-2,3-dihydro-1H-1,3,2-diazaborole (6a) were formed from the corresponding lithiated Z-1,2-diaminoethenes, by treatment with BF3·OEt2, BCl3, or BI3 in n-hexane. Compounds 3a, 5a, and 5b are also available by sodium amalgam reduction of the adduct (tBu)(BF3)N=CH-CH=N(BF3)(tBu) (2a), and the borolium salts [RNa=CH-CH=Nb(R)BCl2]X (Na-B) (4a: R = tBu, X = BCl4 and 4b: R = 2,6-Me2C6H2, X = Cl) respectively. The iodo derivative (2,6-Me2C6H2)-Na-CH=CH-N b(2,6-Me2C6H2)BI (Na-B) (6b) was synthesized in a redox reaction between the 1,4-diazabutadiene 1b and Bl3. The novel compounds were characterized by 1H-, 11B- and 13C-NMR spectroscopy, as well as by an X-ray structure analysis of 6b.
Weber, Lothar,Dobbert, Eckhard,Boese, Roland,Kirchner, Michael T.,Blaeser, Dieter
p. 1145 - 1152
(2007/10/03)

A Direct Route to Halogenated Arsaborane Clusters: Crystal Structure of 3,4,5,6-Tetrachloro-1,2-diarsa-closo-hexaborane(4)
Copyrolysis of B2Cl4 and AsCl3 at 330 deg C leads to the formation of closo-1,2-As2B4Cl4 (1) and further products the mass spectral evidence of which suggests that they are perchlorinated arsaboranes As2B5Cl5, As4B8Cl6, and As2B10Cl10.The pyrolysis temperature and the molar ratio of the reactants exert an essential influence on the type and distribution of the products.At temperatures above 400 deg C and higher B2Cl4/AsCl3 ratios the formation of As2B10Cl10 is preferred to that of smaller arsaboranes.A single-crystal X-ray study of 1 confirmed that, consistent with its 14-skeletal electron count, the arsaborane adopts a slightly distorted octahedral structure with the arsenic atoms in adjacent cis positions. - Keywords: 1,2-Diarsa-closo-hexaborane(4); Perchlorinated arsaborane clusters
Schaefer, Ronald,Einholz, Wolfgang,Keller, Willi,Eulenberger, Guenther,Haubold, Wolfgang
p. 735 - 736
(2007/10/03)

Reactivity of the diboron tetrahalides. Diboration of ethylene with diboron tetrabromide and thermal decomposition and ligand exchanges of diboron tetrabromide and diboron tetrachloride in carbon tetrabromide and carbon tetrachloride
In contrast to previous assertions, we find that B2Br4 reacts readily with ethylene to generate BBr2CH2CH2BBr2, which can be isolated in 95% yield. While it has been reported numerous times that the disproportionation of B2Cl4, which eventually yields BCl3 and the polyhedral boron halides BnXn (n = 8-12), is slowed by the addition of haloalkenes, we have found that the disproportionation rate of both B2Cl4 and B2Br4 is also significantly decreased by the addition of the haloalkanes CBr4 and CCl4, For example, in the presence of a 7-fold excess of CBr4, the amount of B2Br4 recovered after 198 h at 96°C corresponded to 65% of that originally present. Although less dramatic, significant retardation of the B2Cl4 and B2Br4 disproportionations has also been observed when CCl4 was added. These results are interpreted in terms of the transient formation of (dihaloboryl)alkanes, a proposal that is buttressed by the observation of C(BBr2)4 and partially chlorinated (dihaloboryl)methanes like C(BBrCl)4 which were identified by mass spectrometry. The reaction between B2Br4 and excess CCl4 generates B2Cl4 in 84% yield, but the interaction of B2Cl4 with excess CBr4 does not appear to be an effective route to B2Br4.
Ahmed,Castillo,Saulys,Morrison
p. 706 - 710
(2008/10/08)

Phosphane-Tetrahalodiborane(4) Adducts: Formation of closo-3,4,5,6-Tetrabromo-1,2-diphosphahexaborane(4)
Tetrabromodiborane(4), B2Br4, forms a 1:2 adduct 1 with PBr3, which reacts at 350 deg C to closo-1,2-P2B4Br4 (4a) in 25percent yield.Compound 4a neither rearranges to the 1,6-isomer nor decomposes to an appreciable extent upon heating to 650 deg C.B2Cl4 reacts with equimolar amounts of either tris(trimethylsilyl)phosphane or 1,2-bis(dichlorophosphanyl)ethane to give B2Cl4*P(SiMe3)3 (2) and B2Cl4*Cl2PCH2CH2PCl2 (3), respectively.Compound 2 represents the first phosphane-diborane(4) monoadduct with two boron atoms in different coordination environment.Key Words: Bis(tribromophosphane)-tetrabromodiborane(4) diadduct / closo-3,4,5,6-Tetrabromo-1,2-phosphahexaborane(4)
Keller, Willi,Sneddon, Larry G.,Einholz, Wolfgang,Gemmler, Armin
p. 2343 - 2346
(2007/10/02)

Reactions of the diboron tetrahalides B2Cl4 and B2Br4 with B5H9: Preparation and properties of the (dihaloboryl)pentaborane derivatives 1-BX2B5H8, (X = Br, Cl, F, OCH3, t-Bu, H) and synthesis of (BCl2)3B5H6
The reactions of B2Cl4 with excess B5H9 yield 1-BCl2B5H8 (73%) while those of B2Br4 generate 1-BBr2B5H8 (80%). Ligand exchange of 1-BCl2B5H8 with excess BBr3 forms 1-BBr2B5H8 (86%), that with Hg(CF3)2 results in 1-BF2B5H8 (96%), that with CH3OH generates 1-B(OCH3)2B5H8 (46%), and that with Li(t-Bu) prepares B(t-Bu)(Cl)B5H8 (23%) and B(t-Bu)2B5H8 (20%). The relative thermal stabilities of these products are BF2B5H8 > BCl2B5H8 > BBr2B5H8 > B(OCH3)2B5H8 > B(t-Bu)2B5H8. All of these BX2B5H8 compounds (X = F, Cl, OCH3, t-Bu) decompose to form BX3 and B5H9 as the volatile products. Reactions of BCl2B5H8 with excess B2Cl4 yield (BCl2)3B5H6, a compound of limited thermal stability, but no evidence for further BCl2 substitution on the pentaborane cage was obtained. Reductions of BCl2B5H8 with LiBH4 in C6H5Cl or C6H4Cl2 form apparent equilibrium mixtures of 1:1′,2′-[B5H8][B2H5] and 1:1′-[B5H8][B2H5]. One or both of these compounds decompose with the evolution of B2H6, B5H9, and coupled pentaborane cages (B5H7)n, where n can be at least as large as 8. The 11B NMR and mass spectrometric evidence from the last reaction is consistent with the initial dimerization of the hexaborane 1-BH2B5H8, which is rapidly followed by the formation of 1:1′-[B5H8][B2H5], the cross product arising from the interaction of B2H6 with (BH2B5H8)2, and then isomerization of this heptaborane to 1:1′,2′-[B5H8][B2H5].
Saulys,Morrison
p. 4174 - 4179
(2008/10/08)

Detection of the Isotopomeric closo-Hydrohexaborates 11Bn10B6-nH6(2-), n = 0-6, by Low Temperature Raman Spectroscopy
The low temperature Raman spectra (10 K) of Cs2B6H6 and its 11B and 10B enriched derivatives prepared for the first time show well resolved signals of the B6-cage vibrations ν1(A1g), ν3(Eg) and ν9(T2g) for all isotopomers 11Bn10B6-nH6(2-), n = 0-6.The intensities of the sharp peaks correlate exactly with the statistical abundance ratio.Whereas the frequency decreases by nearly equidistant steps of 7 cm-1 with increasing n values, the geometric isomers for n = 2, 3 and 4 are separated by only about 2 cm-1.The band assignments are verified by Teller-Redlich calculations. - Keywords: closo-Hydrohexaborate, Isotopom ers, Raman Spectra
Preetz, W.,Thesing, J.
p. 121 - 126
(2007/10/02)

2,4,6,8,9,10-Hexachlor-2,4,6,8,9,10-hexaboradamantan
The pyrolysis of alkyldichloroboranes such as MeBCl2, Cl2BCH=CHBCl2, Cl2BCH2BCl2 or (Cl2B)3CH at 450 deg C leads to the formation of hexachloro-hexaboraadamantane, C4H4B6Cl6 (I).The structure - determined by X-ray diffraction - and the spectroscopic data of 2,4,6,8,9,10-hexachloro-2,4,6,8,9,10-hexaboradamantane are in agreement with the classical description as an organoborane, rather than as a molecule with a carborane framework.Substitution reactions are described.The bromo compound C4H4B6Br6 can be prepared by heating Me2BBr or MeBBr2 to 520 deg C.
Haubold, Wolfgang,Keller, Willi,Sawitzki, Gisela
p. 19 - 26
(2007/10/02)

Ein neuer Zugang zu halogenierten Carboranen
The copyrolysis of tetrahalogenodiborane(4) (B2X4, X = Cl, Br) or the halogenated carbon compounds such as CX4 or C2X4 yields the new carboranes C2B5X7 and C2B7Cl9 in addition to the vinyl compound C2Br3BBr2 as some of the products.
Haubold, Wolfgang,Keller, Willi
p. C54 - C56
(2007/10/02)

Reaction chemistry of tris(trimethylsilyl)amine with monohaloboranes
Reactions of tris(trimethylsilyl)amine, N(SiMe3)3, with several monochloroboranes, CH3NCH2CH2N(CH3)BCl, o-OC6H4OBCl, and SCH2CH2SBCl, have been examined, and the ((trimethylsilyl)amino)boranes o-OC6H4OBN(SiMe3)2, [o-OC6H4OB]2NSiMe3, SCH2CH2SBN(SiMe3)2, and [SCH2CH2SB]2NSiMe3 have been prepared and characterized by spectroscopic methods. The molecular structure of [o-OC6H4OB]2NSiMe3 has been determined by single-crystal X-ray diffraction analysis and found to crystallize in the orthorhombic space group P212121 (No. 19) with a = 7.189 (1) ?, b = 19.387 (4) ?, c = 24.508 (4) ?, Z = 8, V= 3416 (1) ?3, and ρcalcd = 1.26 g cm-3. The structure was solved by direct methods, and blocked least-squares refinement converged with RF = 10.1% and RwF = 9.2% on 3012 unique data with F > 2σ(F). The structure contains two independent molecules in the unit cell, and the central nitrogen atoms have a trigonal-planar geometry. Important bond distances include B-Nav = 1,421 (13) ?, Si-Nav = 1.783 (7) ?, and B-Oav = 1.390 (13) ?. Attempts to prepare the 1,3,2-diazaborolidine CH3NCH2CH2N(CH3)BN(SiMe 3)2 and triborylamine compounds by this synthetic method were unsuccessful.
Janik, Jerzy Fr.,Narula, Chaitanya K.,Gulliver, Eric G.,Duesler,Paine, Robert T.
p. 1222 - 1227
(2008/10/08)

Relative reactivities of the small closo carboranes 1,6-C2B4H6 and 2,4-C2B5H7 and of closo-1,10-C2B8H10 toward electrophilic reagents
The relative reactivities of the closo carboranes C2BnHn+2 (n = 4, 5, 8), and some of their derivatives, toward electrophilic reagents of the type RX/AlCl3 (RX = CH3Cl, C2H5Cl, Cl2, Br2) are reported from competition studies. Among the three parent carborane compounds, closo-2,4-C2B5H7 is the most reactive toward an electrophilic type of substitution. Alkyl substituents on closo-2,4-C2B5H7 enhance the reactivity of the compound toward an electrophilic substitution, whereas halogen substituents decrease the reactivity. However, in the closo-1,6-C2B4H6 system, the reactivity of the chloro-substituted compound, 2-Cl-1,6-C2B4H5, toward an electrophilic substitution is greater, at the 4-position, than that of the parent carborane. The nature (halogen or alkyl) and cage position of a substituent on closo-2,4-C2B5H7 appear to have little or no influence on the site of electrophilic substitution.
Nam, Wonwoo,Onak, Thomas
p. 1581 - 1586
(2008/10/08)

Substituent effects on closo-2,4-C2B5H7 derivative rearrangement rates. Comparison of rearrangement pattern and rate constants of a mixed disubstituted carborane, 5-CH3-6-Cl-2,4-C2B5H5, with those of monosubstituted 5-X-2,4-C2B5H6 and disubstituted 5,6-X2 ...
Full title: Substituent effects on closo-2,4-C2B5H7 derivative rearrangement rates. Comparison of rearrangement pattern and rate constants of a mixed disubstituted carborane, 5-CH3-6-Cl-2,4-C2B5H5, with those of monosubstituted 5-X-2,4-C2B5H6 and disubstituted 5,6-X2-2,4-C2B5H5 (X = CH3, Cl): Mechanistic implications and isomer stability correlations. The rearrangement of 5-CH3-6-Cl-closo-2,4-C2B5H5 to an equilibrium mixture of all eight B-CH3-B′-Cl-closo-2,4-C2B5H5 isomers is carried out at 295°C. The first isomer produced is 1-CH3-5-Cl-2,4-C2B5H5 followed by 3-CH3-5-Cl-2,4-C2B5H5. The order of appearance of the other five isomers is as follows: 5-CH3-1-Cl-2,4-C2B5H5, 5-CH3-3-Cl-2,4-C2B5H5, 3-CH3-1-Cl-2,4-C2B5H5, 1-CH3-3-Cl-2,4-C2B5H5, 1-CH3-7-Cl-2,4-C2B5H5. Rearrangement rate comparisons to those of the related mono- and disubstituted compounds 5-X-closo-2,4-C2B5H6 and 5,6-X2-closo-2,4-C2B5H5 (X = CH3, Cl) indicate that (a) the presence of a second substituent accelerates the apparent rearrangement of the first substituent and (b) the effect of Cl in this regard is greater than that of CH3. The rearrangement pattern for 5-CH3-6-Cl-closo-2,4-C2B5H5 rules out a triangle-face-rotation mechanism in which cage-carbon atoms stay in the low-coordination nonadjacent positions and is consistent with a diamond-square-diamond mechanism. The relative stabilities of the eight B-CH3-B′-Cl-closo-2,4-C2B5H5 isomers, after statistical weighting, are 1-CH3-3-Cl- > 3-CH3-5-Cl-> 3-CH3-1-Cl- > 5-CH3-3-Cl- > 1-CH3-5-Cl- > 5-CH3-6-Cl- > 5-CH3-1-Cl- > 1-CH3-7-Cl-C2B5H5. This order of observed isomer stabilities is forecast, with only minor departures, from additive substituent-positional effects.
Abdou, Zahid J.,Abdou, Gaby,Onak, Thomas,Lee, Sharon
p. 2678 - 2683
(2008/10/08)

2n framework electron clusters: Diamagnetic polyhedral boron chlorides, BnCln (n = 8-12), from the thermal disproportionation of diboron tetrachloride
In the presence of elemental mercury, diboron tetrachloride, B2Cl4, is generated from the radio frequency discharge of BCl3 at the rate of 250-350 mg/h. The disproportionation of undiluted B2Cl4 has been examined at a variety of temperatures and found to occur in five stages. The amounts of the polyhedral diamagnetic products, B8Cl8, B9Cl9, B10Cl10, B11Cl11, B12Cl12, and (B9Cl8)2, formed during the reaction are highly dependent upon the thermal history of the sample. In undiluted B2Cl4 the maximum yield of B9Cl9 (29%) occurs at elevated temperatures, 400-450°C, whereas the most B8Cl8 (38%) is produced at 100°C. At temperatures below 100°C, more B12Cl12 than B10Cl10 is observed whereas the reverse is true above 100°C. At ambient temperature the 11B NMR resonances of the polyhedral boron chlorides BnCln (n = 8-12) are all deshielded singlets, 58-78 ppm from BF3·OEt2. The relative thermal stabilities of these compounds, B9Cl9 > B10Cl10 > B11Cl11 > B12Cl12 > B8Cl8, do not correspond to the relative thermal stabilities of 2n + 2 framework electron clusters, such as the borane dianions.
Davan,Morrison
p. 2366 - 2372
(2008/10/08)

Reactivity and conformation of a phosphine-substituted dihalocarbene complex. X-ray crystal structures of [(η5-C5H5)Fe(CO)(PPh3)(CF 2)][BF4] and [(η5-C5H5)Fe(CO)2(CCl 2)][BCl4]
The difluorocarbene complex [CpFe(CO)(PPh3)(CF2)][BF4] (1) was prepared by halide abstraction from CpFe(CO)(PPh3)(CF3) using BF3. The structures of this compound and [CpFe(CO)2(CCl2)][BCl4], 2, determined by single-crystal X-ray diffraction, show the effect of ligand asymmetry on the dihalocarbene orientation. For 1 the plane of the CF2 ligand is tilted 18° away from coplanarity with the CO. Complex 2 adopts a vertical conformation with the plane of the CCl2 ligand bisecting the OC-Fe-CO angle. The orientations of CX2 in 1 and 2 agree with the conformations predicted by the MO treatment of Hoffmann and co-workers; however, low-temperature NMR measurements of 1 indicate that the CF2 group is rapidly rotating in solution, so the energy barrier between the various conformers is low. The reaction of CpFe(CO)(PPh3)(CF3) with BCl3 at low temperatures was followed by low temperature NMR, which indicates the successive formation of CF2, CFCl, and CCl2 complexes. These results substantiate a previously postulated mechanism for halide exchange. Crystal data for 1: space group, monoclinic, P21/c; a = 9.035 (3) A?, b = 24.390 (11) A?, c = 10.745 (5) A?, β = 102.20 (3)°; Z = 4. Crystal data for 2: space group, monoclinic, P21/c; a = 12.238 (4) A?, b = 9.444 (4) A?, c = 13.440 (4) A?, β = 113.55 (3)°; Z = 4.
Crespi, Ann M.,Shriver, Duward F.
p. 1830 - 1835
(2008/10/08)

Tetraborane(8) adducts of strongly basic phosphines
Four methods were developed for the preparation of B4H8·P(CH3)3: the removal of one of the trimethylphosphine ligands from B4H8·P(CH3)3 by B2H4, the hydride removal from B4H9·P(CH3)3- by B2H6, the boron framework expansion of B3H7·THF with the use of B2H4·2P(CH3)3, and the reaction of B3H6·2P(CH3)3 +B3H8- with trimethylamine. The yields were better than 90%. The adduct of tris(dimethylamino)phosphine, B4H8·P[N(CH3)2]3, was prepared by the hydride removal reaction of B4H9·P[N(CH3)2] 3-. Two hypho-class bis(base) adducts of B4H8 were prepared from the above mono(phosphine) adducts. These were B4H8·P(CH3)3·N(CH 3)3 and B4H8·P(CH3) 3·P[N(CH3)2]3. The former existed in two isomeric forms, each being different from the other in the positions of the two different ligands. These compounds were characterized by their 11B, 1H, and 31P NMR spectra.
Kameda, Mitsuaki,Shimoi, Mamoru,Kodama, Goji
p. 3705 - 3709
(2008/10/08)

Process for 1-oxacephem derivatives
A process for preparing compounds of the formula STR1 in which R is hydrogen or methoxy, R1 is a hydroxyl group, R2 is chlorine, bromine, OAc or SHET, R3 is hydrogen or a cleavable carboxy-protecting group preferably selected from loweralkyl, benzyl, benzhydryl, loweralkoxyloweralkyl, loweralkoxybenzyl, phenacyl, trimethylsilyl, 2,2,2-trichloroethyl or pivaloloxy, R4 is hydrogen or a cleavable amino-protecting acyl group, or R4 NH represents phthalimido, and HET is a five or six membered aromatic heterocycle containing 1-4 heteroatoms and optionally substituted with loweralkyl, and from which the corresponding 1-oxacephem derivatives can be prepared is described. The novel intermediate compounds of the formula 1 are produced from a penicillin derivative of formula 1 wherein R, R3 and R4 are as above described and R1 and R2 are both the same halogen, by treatment with a formylating agent in a halogenated hydrocarbon solvent to obtain the corresponding compound in which R1 and R2 are both OCHO which is then treated with less than one molar equivalent of a boron halide to obtain a 2:1 to 4:1 mixture of the corresponding compounds of formula 1 in which R1 is OCHO and R2 is the corresponding halogen or R1 is halogen and R2 is OCHO, and in which the former compound predominates. This mixture is separated and the compound in which R1 is OCHO and R2 is halogen is isolated. This last compound is hydrolyzed and the desired intermediate compound in which R1 is OH and R2 is a halogen is isolated. Alternatively, the compound of formula 1 in which R1 is OCHO and R2 is halogen is subjected to displacement by - OAc or HSHET prior to the hydrolysis.
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(2008/06/13)

Synthesis and characterization of 1-(Cl2B)B5H8 and 1-(Cl2B)-2-ClB5H7: A new boron-boron σ bond
Two new 1-(dichloroboryl)pentaborane(9) derivatives, 1-(Cl2B)B5H8 and 1-(Cl2B)-2-ClB5H7, have been produced via the reaction of BCl3 with B5H9 and 2-ClB5H8, respectively, in the presence of Friedel-Crafts catalysts. These compounds are the first examples of σ bonding between borane cluster atoms and external trigonal boron atoms. The boron-boron bonds undergo cleavage at elevated temperature in the presence of diethyl ether and insert ethylene at ambient temperature to form 1-[2-(dichloroboryl)ethyl]pentaborane(9) derivatives.
Gaines, Donald F.,Heppert, Joseph A.,Coons, Darrell E.,Jorgenson, Michael W.
p. 3662 - 3665
(2008/10/08)

Reaction of (CH3)3L (L = N, P) with chlorinated compounds of closo -2,4-C2B5H7: Net displacement reactions at boron atoms of closo-carboranes
Unlike the parent pentagonal-pyramidal closo-2,4-C2B5H7, both 3-Cl-closo-2,4-C2B5H6 and 5-Cl-closo-2,4-C2B5H6 readily react with (CH3)3L (L = N, P) to form 1:1 adducts. Removal of Cl- from these two adducts, using BCl3, produces the unique [3-(CH3)3L-closo-2,4-C2B5H 6]+ and [5-(CH3)3L-closo-2,4-C2B5H 6]+ cations, respectively. The reaction of (CH3)3N with 1-Cl-closo-2,4-C2B5H6 proceeds with more difficulty than with the other two B-Cl isomers, but once formed, the 1:1 adduct combines with BCl3 to give the rearrangement product [3-(CH3)3N-closo-2,4-C2B5H 6]+[BCl4]-.
Siwapinyoyos, Gowit,Onak, Thomas
p. 156 - 163
(2008/10/08)

2n Framework Electron Clusters: Directed Synthesis of Octachlorooctaborane, B8Cl8. The Activation of CH Bonds
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Emery, S. L.,Morrison, J. A.
p. 6790 - 6791
(2007/10/02)

Oxidation of Diborane(4) Molecules by Chloramines
The boron-boron bonds in the diborane(4) molecules (Me2N)2B-B(NMe2)2 (1), (Me2N)ClB-BCl(NMe2) (5) and Cl2B-BCl2 (8) as in B4Cl4 are cleaved by the chloramines Me2NCl (2), MeNCl2 and EtNCl2 (9).As oxydation products BCl3 or the corresponding aminoborane and diborylamines can be isolated.The interaction of 8 and 2 leads to the formation of Me2NH*BCl3 as additional product. - Elementary chlorine does not only cleave the B-B but also the B-N bond in 1, giving Me2NCl as one of the reaction products. - The properties of the N-ethylbis(dichloroboryl)amine (11) are discussed.
Haubold, Wolfgang,Zurmuehl, Konrad
p. 2333 - 2341
(2007/10/02)

A study on the preparation and rearrangement of the halogenated closo-carboranes ClnC2B4H6-n (n = 1, 2) and ClnC2B5H7-n (n = 1, 2)
Dichloro as well as monochloro derivatives of 1,6-C2B4H6 and 2,4-C2B5H7 are prepared, and the effect of the first chlorine substituent on the position of the entering second chlorine substituent is discussed. Both mono- and dichloro derivatives of C2B5H; rearrange at approximately 300°C to a mixture of isomers.
Takimoto, Chris,Siwapinyoyos, Gowit,Fuller, Keith,Fung, Alexander P.,Liauw, Ling,Jarvis, Wiley,Millhauser, Glenn,Onak, Thomas
p. 107 - 110
(2008/10/08)

Reactions of tris(triphenylphosphine)platinum(0). II. Preparation and properties of boron trichloride and aluminum trimethyl adducts of platinum(0)
Treatment of [(C6H5)3P]3Pt with BCl3 affords [(C6H5)3P]3Pt·2BCl 3 whereas [(C6H5)3P]4Pt affords [(C6H5)3P]3Pt·2BCl 3 and (C6H5)3P·BCl3. Reaction of [(C6H5)3P]3Pt·2BCl 3 with pyridine (py) yields py·BCl3 while pyrolysis of the adduct affords benzene. Treatment of [(C6H5)3P]2Pt·SiF4 with BCl3 yields [(C6H5)3P]2Pt·BCl3 whereas reaction with [Al(CH3)3]2 affords a paramagnetic Pt species and mixed fluoromethylsilanes. Reaction of [(C6H5)3P]3Pt with [Al(CH3)3]2 results in the formation of [(C6H5)3P]2Pt·2Al(CH 3)3 which readily decomposes in solution to yield two weakly paramagnetic species. One radical is associated with Pt and the other with Al.
Durkin,Schram
p. 1054 - 1059
(2008/10/08)

The reaction of 1,2-disilyldisiloxane, 1-silyldisiloxane, and 1,1,1-trimethyldisiloxane with boron trichloride
Two new unsymmetrical disiloxanes, 1-silyldisiloxane, SiH3SiH2OSiH3, and 1,1,1-trimethyldisiloxane, (CH3)3SiOSiH3, have been synthesized and characterized. 1,2-Disilyldisiloxane, (SiH3SiH2)2O, underwent reaction with BCl3 to yield SiH3SiH2Cl. Preferential cleavage of certain silicon-oxygen bonds was observed when (CH3)3SiOSiH3, SiH3SiH2OSiH3, and also a mixture of (SiH3SiH2)2O and (SiH2)2O were treated with BCl3. The results are discussed.
Van Dyke, Charles H.,MacDiarmid, Alan G.
p. 747 - 752
(2008/10/08)