Synthesis of diamondlike systems employing allylboranes

Mikhaĭlov, B. M.; Смирнов, В. Н.

doi:10.1007/bf00927281

Cited by 4 publications

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“…It has been postulated that the pyramidalization of the bridgehead boron atom imposed by the skeleton of 2 results in its enhanced Lewis acidity and consequently greater stability of complexes with Lewis bases. This additional stabilization energy has been estimated at about 6 kcal/mol , by comparison of enthalpies of dissociation with the analogous complexes of BMe 3 ( 3 ). In consequence, no dissociation of the complex 2-P has been observed at 200 °C, and no decomposition upon recrystallization from alcohol, , while the parent borane 2 reacts vigorously with air .…”

Section: Introductionmentioning

confidence: 99%

“…This additional stabilization energy has been estimated at about 6 kcal/mol , by comparison of enthalpies of dissociation with the analogous complexes of BMe 3 ( 3 ). In consequence, no dissociation of the complex 2-P has been observed at 200 °C, and no decomposition upon recrystallization from alcohol, , while the parent borane 2 reacts vigorously with air . This relatively high thermal and chemical stability of 1-boraadamantane complexes reflects positively on the possibility to use 1-borabicyclo[2.2.2]octane ( 1 ) as a structural element of liquid crystals …”

Section: Introductionmentioning

confidence: 99%

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1-Pyridine- and 1-Quinuclidine-1-boraadamantane as Models for Derivatives of 1-Borabicyclo[2.2.2]octane. Experimental and Theoretical Evaluation of the B−N Fragment as a Polar Isosteric Substitution for the C−C Group in Liquid Crystal Compounds

et al. 2009

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The suitability of 1-borabicyclo[2.2.2]octane (1) as a structural element for liquid crystals was evaluated using computational methods and experimental studies of two complexes of its close analogue 1-boraadamantane (2). The molecular and crystal structures for 1-pyridine-1-boraadamantane [2-P, C(14)H(20)BN, P2(1)/m, a = 8.4404(13) A, b = 6.8469(10) A, c = 10.5269(16) A, beta = 104.712(3) degrees, Z = 2], 1-quinuclidine-1-boraadamantane [2-Q, C(16)H(28)BN, P2(1)/n, a = 6.6529(3) A, b = 10.6665(6) A, c = 19.3817(10) A, beta = 94.689(3) degrees, Z = 4], and 1-pyridine-trimethylborane [3-P, C(8)H(14)BN, C(cma), a = 6.9875(10) A, b = 15.011(2) A, c = 16.556(2) A, Z = 8] were determined by X-ray crystallography and compared with the results of DFT and MP2 calculations. Gas-phase thermodynamic stabilities of complexes 1-P, 1-Q, 2-P, and 2-Q were estimated using a correlation between theoretical (MP2/6-31+G(d)//MP2/6-31G(d) with B3LYP/6-31G(p) thermodynamic corrections) and experimental data for complexes of BMe(3) (3) with amines lacking N-H bonds. The analysis showed the generally higher thermodynamic stability for the quinuclidine (Q) complexes compared to that of the pyridine (P) analogues in the gas phase and an overall order of stability of 1 > 2 > 3. This order is paralleled by high ring strain energy of 1 (SE = 27 kcal/mol) as compared to that of 1-boraadamantane (2, SE = 16.5 kcal/mol). The chemical stability of 2-P and 2-Q, with respect to hydrolytic and oxidative reagents, is high for the pyridine derivative and satisfactory for the quinuclidine complex at ambient temperature, which implies sufficiently high stability of 1-borabicyclo[2.2.2]octane complexes for materials applications. Molecular dipole moments of 6.2 +/- 0.1 and 6.0 +/- 0.15 D were measured for 2-Q and 2-P, respectively.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

1-Pyridine- and 1-Quinuclidine-1-boraadamantane as Models for Derivatives of 1-Borabicyclo[2.2.2]octane. Experimental and Theoretical Evaluation of the B−N Fragment as a Polar Isosteric Substitution for the C−C Group in Liquid Crystal Compounds

et al. 2009

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“…Note that compound 3 was not properly characterised and for the first time was assumed to have a structure of 3-allyl-6methylene-7,7-dimethyl-3-borabicyclo[3.3.1]nonane, [4][5][6] which corresponds to the vinylborane 6a-like product formation at the first stage of condensation.…”

mentioning

confidence: 99%

“…We recently developed a helix electronic theory for molecular chirality and chiral interaction. [3][4][5][6] The work shows that structurally diverse chiralitites can be generalized on the basis of their inherent helicities. This helix approach suggests that effects conventionally attributed to steric hindrance might instead have an electronic basis, and that a new electronic effect, which we call homohelical interaction, generally controls the stereochemical course of chiral processes.…”

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confidence: 99%