Hexakis(dimethylamino)cyclohexaboran, eine Bor(I)-Verbindung ohne Elektronenmangel

Nöth, Heinrich; Pommerening, H.

doi:10.1002/ange.19800920624

Cited by 47 publications

(13 citation statements)

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“…[10] Boron compounds otherwise tend to form higher aggregated clusters rather than linear chains. [14] Recently, a B 4 R 4 chain was stabilized in the coordination sphere of a transition metal. [14] Recently, a B 4 R 4 chain was stabilized in the coordination sphere of a transition metal.…”

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confidence: 99%

“…[11] Although hints were given for the existence of a linear B 8 (NMe 2 ) 10 com-pound, [12] the only structurally characterized longer derivatives are B 4 (NMe 2 ) 6 [13] and a cyclic species, B 6 (NMe 2 ) 6 . [14] Recently, a B 4 R 4 chain was stabilized in the coordination sphere of a transition metal. [15] All of the examples reveal the requirement of organic substituents for catenation.…”

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confidence: 99%

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Cationic Chains of Phosphanyl‐ and Arsanylboranes

et al. 2014

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Whilst catena-phosphorus cations have been intensively studied in the last years, mixed Group 13/15 element cationic chains have not yet been reported. Reaction of the pnictogenboranes H2EBH2⋅NMe3 (E=P, As) with monohalideboranes lead to the cationic chain compounds [Me3N⋅BH2EH2BH2⋅NMe3][X] (E=P, As; X=AlCl4 , I) and [Me3N⋅BH2PH2BH2PH2BH2⋅NMe3][X] (X=I, VCl4(thf)2), respectively. All of the compounds have been characterized by X-ray structure analysis, NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations elucidate the reaction pathway, the high thermodynamic stability, the charge distribution within the chain and confirm the observed solid-state structures.

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confidence: 99%

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Cationic Chains of Phosphanyl‐ and Arsanylboranes

et al. 2014

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“…[1] This isomerization corresponds to the observation that crystals of 2b transform into 1b above 137°C. [2] In solution, however, cyclohexaborane 1b was reported to isomerize spontaneously into hypercloso-hexaborane 2b at room temperature.…”

Section: Syntheses and Nmr Spectroscopic Characterizationmentioning

confidence: 79%

“…[1] In 1991, Baudler et al described cyclohexaborane isomer 1b of B 6 (NEt 2 ) 6 as well as octahedral isomer 2b, the exact geometry of which could not be determined because of disorder of the crystals. [2] The same problem arose with 2b, which was prepared by the group of Siebert by a new route.…”

Section: Introductionmentioning

confidence: 99%

hypercloso‐Hexa(amino)hexaboranes: Structurally Related to Known hypercloso‐Dodecaboranes, Metastable with Regard to Their Classical Cycloisomers

et al. 2009

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B6(NMe2)6 (2a) is the first neutral hypercloso‐hexaborane to be characterized by X‐ray structural analysis. The geometry of 2a is in nice agreement with that of the Ci symmetric molecule computed at the B3LYP/6‐311+G** level of theory. Two B3 triangles with long B···B distances in 2a are reminiscent of those in Hawthorne's benzyloxy‐substituted hypercloso‐dodecaboranes 6a,b. Upon heating to 200 °C, 2a transforms into Nöth's classical cyclohexaborane 1a. Computations at the B3LYP/6‐311+G** + ZPE level of theory show 1a to be 21.6 kcal mol–1 lower in energy than 2a, that is, the latter is metastable. hypercloso‐Hexaborane B6(NEt2)6 (2b), which was reported to be thermodynamically more stable than 1b, is computed to be 22.4 kcal mol–1 less stable than 1b. Pure 1b is shown here not to transform into 2b upon standing in solution, which is in contrast to reports in the literature for a mixture containing 1b. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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“…Instead, we observed the formation of the orange-red cyclo-hexaborane 7a in 1 % yield. 7a was first reported in 1980 [7]. Ten years later, the corresponding diethylamino derivative 7b was described, and it was found that on standing in solution the orange-red color of 7b changed to green [8].…”

Section: Cyclo-boranes and Polyhedral-boranesmentioning

confidence: 99%

Small boranes, carboranes, and heterocarboranes

Siebert

Maier

et al. 2003

Pure and Applied Chemistry

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Dehalogenation of 1,2-dichloro-diborane(4) derivatives with Na/K alloy does not lead to planar cyclo-tetraboranes but to the blue puckered diisopropylamino compound and to the yellow 2,2,6,6-tetramethylpiperidino-tetraboratetrahedrane derivative, respectively. With smaller dialkylamino substituents, the formation of orange-red cyclo-hexaborane (BNMe 2 ) 6 and the green closo-hexaborane (BNEt 2 ) 6 is observed. When a 1:1 mixture of Me 2 NBCl 2 and [Me 2 N(Cl)B] 2 is dehalogenated, a small amount of colorless crystals of the planar diamond-shaped tetrabora-bicyclo-butane [(Me 2 N) 2 BB−BNMe 2 ] 2 is obtained. Its MO analysis reveals that eight framework electrons are used to form two 3c,2e σ bonds, one 4c,2e π bond, and one 4c,2e σ bond along the edges.A new approach to reactive closo-dicarbapentaboranes involves the hydroboration of dichloroboryl-tbutylacetylene with HBCl 2 leading to Me 3 CCH 2 C(BCl 2 ) 3 . On heating, it is transformed into the closo-dicarbapentaborane (Me 3 CCH 2 C) 2 (BCl) 3 , in which the chlorine atoms may be substituted to give new derivatives.By reacting B 2 Cl 4 with C 5 Me 5 -SiMe 3 the nido-1-borane-2,3,4,5,6-pentacarbahexaborane(6) is stabilized by the Lewis acid BCl 3 to give (MeC) 5 B−BCl 3 .Hydroboration of 3,4-bis(isopropylidene)-1,3-diborolanes leads to the formation of nido-2,3,5-tricarbahexaboranes(7), which may be deprotonated to give the corresponding anions isolobal with C 5 H 5 − . Heterotricarbahexaboranes are obtained when a 3,4-bis(dichloroboryl)-2,5-hexadiene derivative is reacted with heptamethyldisilazane and hexamethyl-disilthiane to give the corresponding 1,2,5-azadiborolane and thiadiborolane. Their hydroboration leads to the aza-and thia-nido-dicarbahexaboranes, respectively.

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Hexakis(dimethylamino)cyclohexaboran, eine Bor(I)-Verbindung ohne Elektronenmangel

Abstract: Einen B6‐Ring in Sesselkonformation enthält die Titelverbindung (1), die aus Destillationsrückständen bei der Enthalogenierung von [(CH3)2N]2BCl kristallisiert. (1) ist der erste Homocyclus des Bors und zugleich die erste Bor(I)‐Verbindung ohne Elektronenmangel.

Cited by 47 publications

References 17 publications

Cationic Chains of Phosphanyl‐ and Arsanylboranes

Cationic Chains of Phosphanyl‐ and Arsanylboranes

hypercloso‐Hexa(amino)hexaboranes: Structurally Related to Known hypercloso‐Dodecaboranes, Metastable with Regard to Their Classical Cycloisomers

Small boranes, carboranes, and heterocarboranes

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