Synthesis of triazenes and amines of the carborane series

Polyakova, L. A.; Bilevich, K. A.; Bregadze, V. I.; Okhlobystin, O. Yu.

doi:10.1007/bf00851230

Cited by 10 publications

(6 citation statements)

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“…[36] Carboranes containing two amino groups are far less studied and only 1,7-(H 2 N) 2--1,7-closo-C 2 B 10 H 10 and 1,12-(H 2 N) 2 -1,12-closo-C 2 B 10 H 10 were described, whereas the 1,2-isomer was reported to be less stable. [37,38] The applications of their derivatives are often similar to those of the isoelectronic closo-borates. For example, they serve as ligands in coordination chemistry, [39] building blocks in medicinal chemistry, [28,33,40] and as monomeric precursors for polymers.…”

Section: Salts Of the [1-h 2 N-closo-cb 11 H 11 ]mentioning

confidence: 98%

Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H₂N‐closo‐CB₁₁H₁₀] (R=H, Ph, H₂N, CyHN)

Finze

2009

Chemistry A European J

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The first primary 2-aminocarba-closo-dodecaborates [1-R-2-H(2)N-closo-CB(11)H(10)](-) (R=H (1), Ph (2)) have been synthesized by insertion reactions of (Me(3)Si)(2)NBCl(2) into the trianions [7-R-7-nido-CB(10)H(10)](3-). The difunctionalized species [1,2-(H(2)N)(2)-closo-CB(11)H(10)] (3) and 1-CyHN-2-H(3)N-closo-CB(11)H(10) (H-4) have been prepared analogously from (Me(3)Si)(2)NBCl(2) and 7-H(3)N-7-nido-CB(10)H(12). In addition, the preparation of [Et(4)N][1-H(2)N-2-Ph-closo-CB(11)H(10)] ([Et(4)N]-5) starting from PhBCl(2) and 7-H(3)N-7-nido-CB(10)H(12) is described. Methylation of the [1-Ph-2-H(2)N-closo-CB(11)H(10)](-) ion (2) to produce 1-Ph-2-Me(3)N-closo-CB(11)H(10) (6) is reported. The crystal structures of [Et(4)N]-2, [Et(4)N]-5, and 6 were determined and the geometric parameters were compared to theoretical values derived from DFT and ab initio calculations. All new compounds were studied by NMR, IR, and Raman spectroscopy, MALDI mass spectrometry, and elemental analysis. The discussion of the experimental NMR chemical shifts and of selected vibrational band positions is supported by theoretical data. The thermal properties were investigated by differential scanning calorimetry (DSC). The pK(a) values of 2-H(3)N-closo-CB(11)H(11) (H-1), 1-H(3)N-closo-CB(11)H(10) (H-7), and 1,2-(H(3)N)(2)-closo-CB(11)H(10) (H(2)-3) were determined by potentiometric titration and by NMR studies. The experimental results are compared to theoretical data (DFT and ab initio). The basicities of the aminocarba-closo-dodecaborates agree well with the spectroscopic and structural properties.

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Section: Salts Of the [1-h 2 N-closo-cb 11 H 11 ]mentioning

confidence: 98%

Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H₂N‐closo‐CB₁₁H₁₀] (R=H, Ph, H₂N, CyHN)

Finze

2009

Chemistry A European J

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“…Previous density‐functional theory (DFT) computations indicated that 1,2‐(NH 2 ) 2 ‐ o ‐carboranes could have strikingly long C−C bonds . However, there are relatively few known species with direct o ‐carboranyl C−N bonds and no experimental report on the synthesis of 1,2‐(NH 2 ) 2 ‐ o ‐carborane . Herein, structural evidence for exceptionally long C−C bonds in 1,2‐diamino‐substituted o ‐carborane systems are reported in which the C−C distances are controlled by negative hyperconjugation between the lone pairs at nitrogen atoms (LP N ) and the antibonding orbitals of the C−C bond (σ* C−C ).…”

Section: Figurementioning

confidence: 91%

Exceptionally Long C−C Single Bonds in Diamino‐o‐carborane as Induced by Negative Hyperconjugation

Pang

et al. 2018

Angew Chem Int Ed

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The synthesis of a series of 1,2‐diamino‐o‐carboranes (1–4) is reported. The molecular structures of these diamino‐o‐carboranes are remarkable as the inner‐cluster C−C bonds are all ultra‐long (162.7–193.1 pm) and vary substantially with small variations in the substituents. The results of quantum mechanical investigations suggest that the origin of the bond elongation is significant in‐plane negative hyperconjugation of lone pairs of the nitrogen substituents with the σ* orbitals of the C−C bonds in o‐carboranes.

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“…An alternative approach to the desired C-amino carboranes utilizes the acid-catalyzed cleavage of triazines that can be obtained from carboranyllithium and phenylazide in about 80% yield 102 .…”

Section: Carbon Substitutionmentioning

confidence: 99%

Four Decades of Organic Chemistry of closo-Boranes: A Synthetic Toolbox for Constructing Liquid Crystal Materials. A Review

Kaszyński

1999

Collect. Czech. Chem. Commun.

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Introduction and transformations of organic functional groups to ten- and twelve-vertex closo-boranes and heteroboranes is reviewed in the context of preparation of liquid crystalline compounds. The review, containing 198 references, is designed as a synthetic manual for materials chemists and focuses on methods for engineering molecules with elongated shapes and variable dipole moments. Several underdeveloped aspects of closo-borane chemistry are identified.

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Synthesis of triazenes and amines of the carborane series

Cited by 10 publications

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Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H₂N‐closo‐CB₁₁H₁₀] (R=H, Ph, H₂N, CyHN)

Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H₂N‐closo‐CB₁₁H₁₀] (R=H, Ph, H₂N, CyHN)

Exceptionally Long C−C Single Bonds in Diamino‐o‐carborane as Induced by Negative Hyperconjugation

Four Decades of Organic Chemistry of closo-Boranes: A Synthetic Toolbox for Constructing Liquid Crystal Materials. A Review

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Synthesis of triazenes and amines of the carborane series

Cited by 10 publications

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Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H2N‐closo‐CB11H10] (R=H, Ph, H2N, CyHN)

Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H2N‐closo‐CB11H10] (R=H, Ph, H2N, CyHN)

Exceptionally Long C−C Single Bonds in Diamino‐o‐carborane as Induced by Negative Hyperconjugation

Four Decades of Organic Chemistry of closo-Boranes: A Synthetic Toolbox for Constructing Liquid Crystal Materials. A Review

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Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H₂N‐closo‐CB₁₁H₁₀] (R=H, Ph, H₂N, CyHN)

Synthesis and Characterization of 2‐Mono‐ and 1,2‐Diaminocarba‐closo‐dodecaborates M[1‐R‐2‐H₂N‐closo‐CB₁₁H₁₀] (R=H, Ph, H₂N, CyHN)