- Practical synthesis for decahydrodecaborates
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High-yield synthesis of the decahydrodecaborate(2-) anion was achieved from the thermolysis of tetraethylammonium tetrahydroborate(1-), (C2H5)4NBH4, and tetraethylammonium octahydrotriborate(1-), (C2H5)4NB3H8, at atmospheric pressure and 185°. The thermolysis of tetramethylammonium tetrahydroborate(1-), (CH3)4NBH4, under similar conditions gives only trimethylamine borane, (CH3)3NBH3, and methane, while a near equimolar mixture of [(CH3)4N]2B10H10 and [(CH3)4N]2B12H12 was the major product obtained from pyrolysis of tetramethylammonium octahydrotriborate(1-), (CH3)4NB3H8. Although B10H102- was a major product, complex mixtures of products containing the BH4-, B10H102-, B11H14-, and B12H122- anions were obtained from the 185° pyrolysis of potassium and cesium octahydrotriborates(1-), KB3H8 and CsB3H8, respectively. No evidence was obtained for B9H92- or B11H112- when the pyrolysis temperatures were maintained at 185°.
- Makhlouf, Joseph M.,Hough, William V.,Hefferan, Gerald T.
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- Reduction of hydroxy-functionalised carbaboranyl carboxylic acids to tertiary alcohols by organolithium reagents
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Reduction of hydroxy-functionalised carbaboranyl carboxylic acids by organolithium reagents yields the corresponding tertiary alcohols. This is in contrast to exo-polyhedral C-C bond cleavage of unsubstituted carbaboranyl carboxylic acids upon reaction with lithium organyls. The proposed dimeric contact ion pairs may also explain the formation of tertiary alcohols instead of the expected ketones.
- Neumann, Wilma,Hiller, Markus,Loennecke, Peter,Hey-Hawkins, Evamarie
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- A novel approach to ortho-carborane by decarboranylation of 1-(isopropyl benzoate)-1,2-dicarba-closo-dodecaborane
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Abstract A novel approach was successfully developed for the synthesis of ortho-carborane [1,2-dicarba-closo-dodecaborane(12)] by reaction of 1-(isopropyl benzoate)-1,2-dicarba-closo-dodecaborane with KOH in methanol at 20 C. A decarboranylation in base of the first formed alcoholysis intermediate product 1-(2-propanol)-1,2-dicarba-closo-dodecaborane was suggested for this process.
- Feng, Chen,Zhang, Haicheng,Yang, Jiping,Chen, Gong
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- Access to carbaboranyl glycophosphonates - An odyssey
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Novel bis-phosphonate derivatives of carbaboranes, which might be potential boron-delivery agents for boron neutron capture therapy, are described. Conceivable synthetic routes which failed to give the desired compounds are discussed, and finally, a highl
- Stadlbauer, Sven,Welzel, Peter,Hey-Hawkins, Evamarie
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- Carboranes. I. The preparation and chemistry of 1-isopropenylcarborane and its derivatives (a new family of stable clovoboranes)
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The preparation of the first member of a new family of stable polycyclic boranes is reported. Treatment of isopropenyl-acetylene with derivatives of decaborane of the form B10H12·L2 (where L is any one of several Lewis bases) or with mixtures of decaborane and L give the new polycyclic borane. The general applicability of this reaction to other acetylenes is also reported. The cycloboranes which are formed contain a =C2B10H10 unit and are members of the generic family, C2BnHn+2. The nucleus exhibits a high degree of oxidative, hydrolytic, and thermal stability.
- Fein, Marvin M.,Bobinski, Jack,Mayes, Nathan,Schwartz, Nelson,Cohen, Murray S.
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- Carbon extrusion in 1,2-dicarba-closo-dodecaboranes: Regioselective boron substitution in ten-vertex closo-monocarbaborane anions
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(Chemical Equation Presented) A nonclassical carbon atom of a dicarbaborane is converted into a classical carbon atom, and the substituent increases in length by one CH2 group (see scheme). This is the path followed to form [1-Me-6-Et-1-closo-CB9H8]- regioselectively from [1,2-Me2-1,2-closo-C2B 10H10]. First, the o-carborane derivative is reduced to [7-Me-μ-(9,10-HMeC)-7-nido-CB10H11]-, and then a carbon-atom extrusion followed by selective deboronation takes place.
- Laromaine, Anna,Teixidor, Francesc,Vinas, Clara
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- Reduction of hydroxy-functionalised carbaboranyl carboxylic acids and ketones by organolithium reagents
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While the reaction of carbaboranyl carboxylic acids and ketones with organolithium reagents generally leads to cleavage of the exo-polyhedral C-C bond, introduction of a hydroxyl group at the second carbon atom of the cluster enables the reduction of the carbonyl compounds to tertiary alcohols. The proposed mechanism involving the formation of dimeric contact ion pairs was supported by X-ray crystallography and theoretical calculations. This journal is
- Neumann,Hiller,Sárosi,L?nnecke,Hey-Hawkins
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- A new series of organoboranes. I. Carboranes from the reaction of decaborane with acetylenic compounds
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Decaborane and certain of its derivatives reacted with acetylenic compounds in the presence of Lewis bases to produce members of a new class of organoboranes. The parent compound 1,2-dicarbaclovododecaborane(12) has the formula B10C2H12 and various C and B substituted derivatives are reported. Unlike other higher boranes, this nucleus is quite impervious to attack by compounds containing active hydrogen and it does not attack reducible groups such as carbonyl or nitrite.
- Heying,Ager Jr.,Clark,Mangold,Goldstein,Hillman,Polak,Szymanski
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- The BI activation in o-carborane clusters: their fate towards BH. Easy synthesis of [7,10-C2B10H13]-
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The reaction of 3-I-o-carborane with Cu, Cu/PPh3, [Ni(PPh3)3], or [Pd(PPh3)4] has been studied to find the suitability of B-iodine substituted carboranes as sources of new boron-derivatives. In all these reactions a hydrodehalogenation reaction to yield o-carborane has been produced, indicating that BI activation takes place. It may be considered that BI adds oxidatively to M, but alternative explanations can be given. Reaction of 3-I-o-carborane with Na/naphthalene also produced o-carborane showing that albeit an oxidative addition is impossible for sodium the same hydrodehalogenation had taken place. The same result was also formed with Mg. Addition of 1,2-dibromoethane to the Mg/o-carborane reaction yielded [7,10-C2B10H13]-. Then, the sequence 3-I-o-carborane→o-carborane→[7,10-C2B10H13]- can be generated with only reducing agents. The synthetic procedure for [7,10-C2B10H13]- is very simple and produces a 97% yield of [NMe4][7,10-C2B10H13]. Basically, 1,2-C2B10H12 and Mg in excess are refluxed in THF in the presence of I2 and 1,2-dibromoethane.
- Vi?as, Clara,Barberà, Gemma,Teixidor, Francesc
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- Preparation and Properties of Inclusion Complexes of 1,2-Dicarbadodecaborane(12) with Cyclodextrins
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One-to-one inclusion complexes were obtained in a crystalline state in high yields by treatment of β- and γ-cyclodextrin with 1,2-dicarbadodecaborane(12) (o-carborane), whereas α-cyclodextrin formed a 2:1 (cyclodextrin: guest) complex on sonication, and a 1:1 complex on crystallization from water-propan-2-ol.
- Harada, Akira,Takahashi, Shigetoshi
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- Mechanochemical Iridium(III)-Catalyzed B-Amidation of o-Carboranes with Dioxazolones
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Mechanochemistry was successfully applied to the functionalization of carboranes. The mechanochemical iridium(III)-catalyzed regioselective B(3)- and B(4)-amidation of unsubstituted o-carboranes with dioxazolones was developed. In addition, the mechanochemical iridium(III)-catalyzed regioselective B(4)-amidation of substituted o-carboranes was demonstrated. Because mechanochemical B-amidation proceeds smoothly without organic solvents or external heating, the present method is regarded as a sustainable and environmentally friendly surrogate for typical solvent-based reactions.
- Han, Gi Uk,Shin, Seohyun,Baek, Yonghyeon,Kim, Dongwook,Lee, Kooyeon,Kim, Jeung Gon,Lee, Phil Ho
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supporting information
p. 8622 - 8627
(2021/11/13)
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- Metal-Free Oxidative B?N Coupling of nido-Carborane with N-Heterocycles
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A general method for the oxidative substitution of nido-carborane (7,8-C2B9H12?) with N-heterocycles has been developed by using 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) as an oxidant. This metal-free B?N coupling strategy, in both inter- and intramolecular fashions, gave rise to a wide array of charge-compensated, boron-substituted nido-carboranes in high yields (up to 97 %) with excellent functional-group tolerance under mild reaction conditions. The reaction mechanism was investigated by density-functional theory (DFT) calculations. A successive single-electron transfer (SET), B?H hydrogen-atom transfer (HAT), and nucleophilic attack pathway is proposed. This method provides a new approach to nitrogen-containing carboranes with potential applications in medicine and materials.
- Yang, Zhongming,Zhao, Weijia,Liu, Wei,Wei, Xing,Chen, Meng,Zhang, Xiao,Zhang, Xiaolei,Liang, Yong,Lu, Changsheng,Yan, Hong
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supporting information
p. 11886 - 11892
(2019/07/18)
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- Syntheses and reductions of C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes
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Two C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes, 1-(BMes2)-2-R-1,2-C2B10H10 (1, R = H, 2, R = Ph), were synthesised by lithiation of 1,2-dicarba-closo-dodecaborane and 1-phenyl-1,2-dicarba-closo-dodecaborane, respectively, with n-butyllithium and subsequent reaction with fluorodimesitylborane. These novel compounds were structurally characterised by X-ray crystallography. Compounds 1 and 2 are hydrolysed on prolonged exposure to air to give mesitylene and boronic acids 1-(B(OH)2)-2-R-1,2-C2B10H10 (3, R = H, 4, R = Ph respectively). Addition of fluoride anions to 1 and 2 resulted in boryl-carborane bond cleavage to give dimesitylborinic acid HOBMes2. UV absorption bands at 318-333 nm were observed for 1 and 2 corresponding to local π-π-transitions within the dimesitylboryl groups while visible emissions at 541-664 nm with Stokes shifts of 11 920-16 170 cm-1 were attributed to intramolecular charge transfer transitions between the mesityl and cluster groups. Compound 2 was shown by cyclic voltammetry to form a stable dianion on reduction. NMR spectra for the dianion [2]2- were recorded from solutions generated by reductions of 2 with alkali metals and compared with NMR spectra from reductions of 1,2-diphenyl-ortho-carborane 5. On the basis of observed and computed 11B NMR shifts, these nido-dianions contain bowl-shaped cluster geometries. The carborane is viewed as the electron-acceptor and the mesityl group is the electron-donor in C-dimesitylboryl-1,2-dicarba-closo-dodecaboranes.
- Kahlert, Jan,B?hling, Lena,Brockhinke, Andreas,Stammler, Hans-Georg,Neumann, Beate,Rendina, Louis M.,Low, Paul J.,Weber, Lothar,Fox, Mark A.
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p. 9766 - 9781
(2015/06/08)
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- Thermal isomerizations of monothiolated carboranes (HS)C2B10H11 and the solid-state investigation of 9-(HS)-1,2-C2B10H11 and 9-(HS)-1,7-C2B10H11
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At 300-500 °C, three C-thiolated closo-dicarbadodecaborane isomers 1-(HS)-1,2-C2B10H11 (1-o), 1-(HS)-1,7-C2B10H11 (1-m), and 1-(HS)-1,12-C2B10H11 (1-p), and two B-thiolated isomers 9-(HS)-1,7-C2B10H11 (9-m) and 9-(HS)-1,2-C2B10H11 (9-o) show two types of reaction: first, removal of an SH group from the closo-dicarbadodecaborane skeleton, and second, skeletal isomerizations from ortho to meta to para that lead to new isomers. A previously unreported SH skip from carbon-to-boron is also observed. The effect of the thiol group on the skeletal rearrangement is discussed. The isomerisation products are assigned on the basis of correlation of their computationally obtained dipole moments with their gas-chromatographic retention times. Computational results on molecular energies for the mono-thiolated species show good agreement between the calculated relative stabilities and the incidence and relative quantities of the isomerization products. Two of the starting B-thiolated isomers, 9-o and 9-m, were characterized using single-crystal X-ray diffraction analyses and their crystallographic packings as well as some selected structural parameters are discussed. All starting compounds were characterized using multinuclear NMR spectroscopy.
- Ba?e, Tomá?,Machá?ek, Jan,Hájková, Zuzana,Langecker, Jens,Kennedy, John D.,Carr, Michael J.
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p. 132 - 140
(2015/12/18)
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- High yielding synthesis of carboranes under mild reaction conditions using a homogeneous silver(I) catalyst: Direct evidence of a bimetallic intermediate
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Methods used to prepare functionalized carboranes generally require heating to high temperatures, and thus limits the range of derivatives which can be prepared directly from alkynes. We show here that by using a homogeneous silver(I) catalyst it is now possible to prepare carboranes in good to excellent yield at temperatures below 40 °C, including at room temperature. The process is general and provides an important new synthetic strategy for the preparation of functionalized boron clusters. Cluster around: Current methods to prepare carboranes require heating to high temperatures, thereby limiting the range of derivatives which can be prepared from functionalized alkynes. By using a AgI catalyst it is possible to prepare carboranes from substituted alkynes in good to excellent yields at temperatures below 40 °C, including room temperature. The approach provides an important new synthetic strategy for the preparation of functionalized boron clusters.
- El-Zaria, Mohamed E.,Keskar, Kunal,Genady, Afaf R.,Ioppolo, Joseph A.,McNulty, James,Valliant, John F.
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p. 5156 - 5160
(2014/05/20)
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- Synthesis of closo- and nido-biscarboranes with rigid unsaturated linkers as precursors to linear metallacarborane-based molecular rods
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Several biscarborane-type derivatives of 8-iodo-1,2-dicarba-closo- dodecaborane (1), suitable as the precursors of linear metallacarborane-based molecular rods, were prepared. The synthesized closo-compounds contained two carborane moieties connected through a rigid linear unsaturated linker. The linkers were based on ethynylene and para-phenylene fragments and their combinations. The deboronation of all reported closo-compounds was selective and afforded nido-products with open pentagonal faces on opposite sides of the molecule, parallel to each other and perpendicular to the main molecular axis. All of the closo and nido products were characterized by a variety of physical methods (NMR, HRMS, IR). The structures of closo-carboranes 3, 6, 9, and 14 and nido-carboranes 15 and 17 were established by X-ray diffraction.
- Safronov, Alexander V.,Sevryugina, Yulia V.,Pichaandi, Kothanda Rama,Jalisatgi, Satish S.,Hawthorne, M. Frederick
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p. 4969 - 4977
(2014/04/03)
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- Synthesis of tellurasila cycles containing an annelated dicarba-closo-dodecaborane(12) unit: Structure of a 1,4-ditellura-2,3- disilacyclohexane derivative
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Insertion of tellurium into C-Li bonds of dilithiated 1,2-dicarba-closo- dodecaborane(12) gave 1,2-dicarba-closo-dodecaborano(12)-1,2-ditellurolate [(1,2-C2B10H10)Te2Li 2](Et2O) which, after reaction with 1,2- dichlorotetramethyldisilane, afforded a six-membered heterocycle containing the Te-Si-Si-Te unit with an annelated carborane moiety, characterized by multinuclear magnetic resonance and X-ray structural analysis. As a byproduct, a five-membered ring containing a Si-Si-Te unit was formed, which was obtained as a major product, using conditions favouring partial insertion of tellurium into C-Li bonds. Treatment of [(1,2-C2B10H10) Te2Li2](Et2O) with dichlorodimethylsilane led to a five-membered heterocycle as a major product containing a Te-Te-Si unit. Various decomposition/hydrolysis/oxidation products could be identified by multinuclear magnetic resonance, among them most notably 1,2-di(hydrotelluro)-1, 2-dicarba-closo-dodecaborane(12). The reactions of 1,2-dicarba-closo- dodecaborano(12)-1,2-ditellurolate with chlorosilanes afforded five-membered silatellura heterocyles containing the TeSiSi or TeTeSi moiety linked with the C2 unit of 1,2-dicarbadodecaborane(12) in addition to the six-membered heterocycle containing the TeSiSiTe fragment. Copyright
- Wrackmeyer, Bernd,Klimkina, Elena V.,Milius, Wolfgang
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p. 398 - 408
(2013/03/28)
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- A spirocyclic borate and a dihydroborate derived from the 1,2-diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion [1,2-(1,2-C 2B10H10)Se2]2-: Structures, NMR spectroscopy, and DFT calculations
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The reaction of the diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion with BF3-OEt2 affords selectively a spirocyclic bis(1,2-dicarba-closo-dodecaborane-1,2-diselena)borate, whereas the analogous reaction with boron trichloride leads mainly to 1,2-bis(ethylseleno)-1,2- dicarba-closo-dodecaborane(12) through ether cleavage. The spirocyclic borate reacts with methanol by cleavage of both Se-B and Se-C bonds. With borane in THF (BH3/THF) and also with LiBH4 exchange reactions take place, which afford the 1,2-dicarba-closo-dodecaborane-1,2- diselenadihydroborate. The molecular structures of both borates as tetrabutylammonium salts were determined by X-ray analysis. In solution, the borates were characterized by multinuclear magnetic resonance spectroscopy (1H, 11B, 13C, 77Se). The gas-phase geometries of the borate anions were optimized [RB3LYP/6-3111+G(d,p) level of theory], and the NMR spectroscopic parameters (chemical shifts and coupling constants) were calculated.
- Wrackmeyer, Bernd,Klimkina, Elena V.,Milius, Wolfgang
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p. 2164 - 2171
(2011/06/26)
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- Synthesis and structural characterization of group 10 metal-carboryne complexes
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A series of group 10 metal-carboryne complexes were prepared from an equimolar reaction of MCl2(PR3)2 with Li 2C2B10H10-nXn (M = Ni, Pd, Pt; X = Br, I, Ph; n = 0, 1, 2). They were fully characterized by various spectroscopic techniques, elemental analyses, and X-ray diffraction studies. These complexes have similar solid-state structures, in which the metal atom is bonded to two cage carbon atoms and coordinated to two phosphorus atoms in a planar geometry. The coordinated phosphines are labile and can be replaced by other Lewis bases. The bonding interactions between the metal and the carboryne unit can be described as a resonance hybrid of both the M-C σ- and M-C π-bonding forms. These complexes can be viewed as 16e species.
- Qiu, Zaozao,Deng, Liang,Chan, Hoi-Shan,Xie, Zuowei
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p. 4541 - 4547
(2010/12/20)
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- Synthesis of functionalized carboranes as potential anticancer and BNCT agents
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Carboranyl aldehydes react with α,β-unsaturated esters, ketones, and nitriles in the presence of DABCO to provide functionalized carboranyl alcohols in good yields. Acetates of these alcohols undergo a facile isomerization with a variety of nucleophiles and afford structurally interesting carboranes. Biological evaluation of these molecules exhibited impressive antiproliferative activity for brain and breast cancer cells.
- Reddy, Venkata Jaganmohan,Roforth, Matthew M.,Tan, Chalet,Reddy, M. Venkat Ram
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p. 381 - 383
(2008/10/09)
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- Generation and trapping reaction of an efficient 1,2-dehydrocarborane precursor, phenyl[0-(trimethylsilyl)carboranyl]iodonium acetate
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An efficient 1,2-dehydrocarborane precursor, phenyl[o-(trimethylsilyl)carboranyl]iodonium acetate 4, was readily prepared by reaction of [o-(trimethylsilyl)carboranyl]lithium and IPh(OAc)2. The facile 2+4 cycloaddition of 4 with dienes such as anthracene, naphthalene, norborna-2,5-diene and 2,5-dimethylfuran gave high yields of the 1,2-dehydrocarborane adducts in the presence of a desilylating agent. The reaction of 4 with a cyclic alkene and strained cycloalkynes afforded the adducts formed by the ene reaction and the 2+2 cycloaddition reaction. The reaction of 2 with a bicyclopalladacycle yielded the cyclization product. The structures ofcompounds 5 and 7 were determined by single-crystal X-ray crystallograp hy.
- Lee, Taegweon,Jeon, Joonsang,Song, Kyu Ho,Jung, Il,Baik, Chul,et al.
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- Unusual reactivities of linear disilanes with o-carboranyl unit
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The linear disilanes l,2-bis(1′-R-o-carboranyl)-1,1,2,2-tetramethyl-1,2-disilane (R = H (2a), Me (2b), Ph (2c)) were prepared by reacting the lithium salt of 1-R-o-carborane (1) with 1,2-dichlorotetramethyldisilane. These linear disilanes (2) were found to be useful precursors for the synthesis of a variety of cyclic compounds. For instance, reaction of the linear dilithiodisilane 2a with 1,2-dichlorotetramethyldisilane afforded the four-membered cyclic compound 3,4-o-carboranylene-1,1,2,2-tetramethyl-1,2-disilacyclobutane (3). Further, whereas the reaction of linear disilane (2a) with Pt(PEt3)3 was found to yield the cyclic bis(silyl)platinum complex 4, the reaction of the methyl-o-carboranyl-substituted disilane 2b with Pt(PEt3)3 under the same conditions yielded the decomposed bis(silyl)platinum complex 5, formed via oxidative addition of a Si-Si bond at the platinum atom. The reaction of the cyclic disilane 3 using a catalytic amount of lithium metal afforded a five-membered cyclic trisilyl compound (6). The reaction of 6 with phenylacetylene in the presence of a catalytic amount of Pd(CNBut)2 was found to yield the seven-membered trisilyl ring compound 6,7-o-carboranylene-1,1,4,4,5,5-hexamethyl-2-phenyl-l,4,5-trisilacyclohept-2-ene (7). The structures of compounds 2a,b, 4-6, and 7 were determined using single-crystal X-ray crystallography.
- Lee, Young-Joo,Lee, Jong-Dae,Kim, Sung-Joon,Yoo, Byung Woo,Ko, Jaejung,Suh, Il-Hwan,Cheong, Minserk,Kang, Sang Ook
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p. 490 - 497
(2008/10/09)
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- Suzuki Cross Coupling in the Carborane Series
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Products of the Suzuki cross coupling of 9-iodo-m-carborane and 9-iodo-o-carborane with phenylboric acid and with dibutyl vinylboronic acid, catalyzed by various palladium compounds, were studied. It was found that the reaction with carboranes occurs in a much different way than with organohalogen compounds.
- Zakharkin,Balagurova,Lebedev
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p. 922 - 924
(2007/10/03)
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- Directive effects in the hydroboration of 1-alkenyl derivatives of o-carborane with representative hydroborating agents
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A series of 1-alkenyl-o-carboranes was hydroborated using representative hydroborating agents with different steric requirements. The steric and electronic effects of the carboranyl group were evaluated by examining the distribution of the isomeric alcohols obtained after oxidation of the intermediate carboranyl-substituted organoboranes.
- Kabalka,Hondrogiannis
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p. 327 - 337
(2007/10/03)
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- Cathodic cleavage of C-S and C-P in carboranyl derivatives
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An electrochemical cathodic study of sulfur- and phosphorus-carbon substituted derivatives of o-carborane has shown that C-S and C-P bond fission takes place. The 1,2-dithio-1,2-dicarba-closo-dodecaborane(12) derivatives display a marked influence of the S,S′-noncluster linkage in their cathodic behavior. Shorter S,S′ linkages, which produce more strained cycles, give cathodic waves at lower voltages (-1.2 V, Ag/AgCl) than the less strained ones (-1.7 V). These cathodic peaks are attributed to an electrochemical process followed by a chemical one. The compounds with shorter linkages are converted to o-carborane, and no C-S retention has been observed. The compounds with longer linkages provide comparable amounts of o-carborane, 7,8-C2B9H12- and 7,8-SRS-7,8-C2B9H10-. These less strained compounds exhibit some C-S bond retention. The phosphorus derivatives, which are noncyclic, behave like the more strained S mesocycles described above. Only o-carborane is found among the products following the electrochemical process, and in no case has C-P retention taken place.
- Teixidor, Francesc,Pedrajas, Josefina,Vi?as, Clara
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p. 1726 - 1729
(2008/10/08)
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- SYNTHESIS AND SOME TRANSFORMATIONS OF COMPLEX NICKEL(II) SALTS OF BIS(3,1,2-DICARBONYLALLYL)NICKEL(III). PREPARATION OF 3-(2,2'-BIPYRIDYL)-closo-3,1,2-NICKELADICARBADODECABORANE
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III>2NiII*4L compounds (2a,b), where Cb is ?-(3)-1,2-C2B9H11 and L is 2,2'-bipyridyl (2a) or pyridine (2b), have been prepared by the reaction of NiCl2 with III>Na (1) in the presence of the corresponding ligands L.The salt with bipyridyl (1a) forms the complex Na*2L (3).Complexes 2a and 3 decompose at 200-230 deg C to form 3-(2,2'-bbipyridyl)-closo-3,1,2-nickeladicarbadodecaborane (4).Compound 4 has also been prepared by thermal decompositin of bipyridyl complexes of bis-(1-o-carboranyl)nickel or the nickel salt of 1-o-carboranecarboxylic acid.In this case, the o-carboranic nucleus is transformed into a closo-nickelcarboranic one.
- Maier, N. A.,Erdman, A. A.,Zubreichuk, Z. P.,Propkovich, V. P.,Ol'dekop, Yu. A.
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p. 297 - 302
(2007/10/02)
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- Direct synthesis of closo-carboranes
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Pentaborane-9 and acetylene can react in a continuous-flow system to produce directly the smaller closo-carboranes 1,5-C2B3H5, 1,6-C2B4H6, and 2,4-C2B5H7 in combined yields approaching 65-70%. Reactions of decaborane-14 with acetylene under the same conditions, excepting a somewhat higher temperature, give predominantly 1,7-C2B10H12 in yields also on the order of 70%. Optimal conditions for both systems include short residence times (～0.5 sec), high temperatures (500-600°, depending on the system), a diluent gas, and a steel wool plug or diffuser. The reactions are highly exothermic, and drastic reduction of yields can occur if the heat is not dissipated, as was evident in a scaled-up unit where very careful diluent control had to be exercised to prevent sudden surges to very high temperatures.
- Ditter,Klusmann,Oakes,Williams, Robert E.
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p. 889 - 892
(2008/10/08)
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- Carboranes. II. The preparation of 1- and 1,2-substituted carboranes
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The broad applicability o the conversion of mono- and disubstituted acetylenes to carboranes by treatment with decaborane and Lewis bases is demonstrated. The resultant carboranes may then be treated as typically organic, covalent products and, by usual s
- Fein, Marvin M.,Grafstein, Daniel,Paustian, John E.,Bobinski, Jack,Lichstein, Bernard M.,Mayes, Nathan,Schwartz, Nelson N.,Cohen, Murray S.
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p. 1115 - 1119
(2008/10/08)
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- Carboranes. III. Reactions of the carboranes
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The reactions of the carboranyl polyhedron and its influence on the chemistry of organofunctional substituents were investigated. Convenient laboratory syntheses for carborane, 1-methylcarborane, and some functional derivatives were developed. An unusual rearrangement in a Grignard reagent was observed. Metalation, animation, solvolytic degradation, and other reactions of these novel compounds were studied.
- Grafstein, Daniel,Bobinski, Jack,Dvorak, Joseph,Smith, Harry,Schwartz, Nelson,Cohen, Murray S.,Fein, Marvin M.
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p. 1120 - 1125
(2008/10/08)
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