Polyhedral Borane Free Radicals<sup>1</sup>

Lewis, John S.; Kaczmarczyk, Alexander

doi:10.1021/ja00957a045

Cited by 19 publications

(17 citation statements)

References 2 publications

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“…T his is esp ecia lly true for polyborane clusters w ith their otherw ise w elldeveloped chem istry and diverse structures. Reports on BgH s*- [7] and B 1 0 H 1 0 *- [8] have appeared and a neutral polyalkyl substituted carborane species C B iiM e n * w as structurally characterized recently [9]; the isolability o f the latter w as attributed to steric protection o f the carborane cluster core by a "sheath o f m ethyl groups" [9a].…”

mentioning

confidence: 99%

Hexaborate Cluster Radical Anions [B₆Hal_n Hal'_6-n]^.- and [B₆Hal₅R]^.-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy

Wanner

Kaim

Lorenzen

et al. 1999

Zeitschrift Für Naturforschung B

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Paramagnetic hexaborate clusters with mixed halide, halide/alkyl or halide/hydride substi tution were prepared from oxidizable dianionic precursors and were characterized by cyclic voltammetry, EPR, vibrational and UV-VIS spectroscopy. The EPR studies reveal increasing g anisotropy and EPR linewidths on replacing Cl by Br and especially by I substituents; on the other hand, the replacement of one halide by one alkyl (CH3 or CFFCN) or hydride substituent in [BftHalsR]*-causes decreasing radical persistence and g anisotropy. These results indicate a fairly uniform participation of the cluster core and the substituent sphere in the spin distribution as a major factor for the stability of these non-7r radicals.

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mentioning

confidence: 99%

Hexaborate Cluster Radical Anions [B₆Hal_n Hal'_6-n]^.- and [B₆Hal₅R]^.-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy

Wanner

Kaim

Lorenzen

et al. 1999

Zeitschrift Für Naturforschung B

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“…The treatment of 1,2-(CH 2 ) 3 -1,2-C 2 B 11 H 11 (1a), 1,2-(CH 2 ) 3 -3-Ph-1,2-C 2 B 11 H 10 (1b), 1,2-(CH 2 ) 4 -1,2-C 2 B 11 H 11 (1c), 1,2-(CH 2 ) 4 -3-Ph-1,2-C 2 B 11 H 10 (1d), or 1,2-(CH 3 ) 2 -1,2-C 2 B 11 H 11 (1e) with 1 equiv of finely cut sodium (Na) metal in tetrahydrofuran (THF) at room temperature afforded, after recrystallization from a mixed THF/hexane solution of 18-crown-6 ether, the corresponding sodium salts of carborane radical anions as darkred crystals, [1,2-(CH 2 ) 3 These compounds are extremely air-and moisture-sensitive but remain stable for months at room temperature under an inert atmosphere. Traces of air immediately oxidize the radical anions to form closo-carboranes, converting these intensively colored radical anions to pale-yellow powders.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Supercarborane Radical Anions with 2n + 3 Electron Counts: A Combined Experimental and Theoretical Study

Zhang

Lin

et al. 2015

Inorg. Chem.

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The synthesis, structure, spectroscopic characterization, and density functional theory (DFT) calculations of several 13-vertex carborane radical anions were described. Reactions of 13-vertex closo-carboranes with 1 equiv of finely cut sodium metal in tetrahydrofuran at room temperature afforded the corresponding sodium salts of carborane radical anions as dark-red crystals in very good yield. They represent a rare class of clusters having 2n + 3 framework electrons, which lie between the two well-established and abundant closed 2n + 2 (closo) and open 2n + 4 (nido) skeleton systems. However, attempts to prepare the 12- or 14-vertex analogues failed. DFT calculations indicate that the ΔGsol,1 - ΔGsol,2 values, the difference in the solvation-corrected free-energy changes between the first and second one-electron-reduction processes, can be used as a measure for the stability of carborane radical anions. The relatively high stability of 13-vertex carborane radical anions is related to the unique structures of 13-vertex carboranes, which give rise to minimal structure disruption upon the first one-electron reduction.

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“…X = H, n = 8). 43,44 Several theoretical studies have appeared later for species with X = H 45,46 and the attention was also extended to perhalide compounds (X = Hal, n = 6, 8, 9, 10), [47][48][49][50][51][52][53][54][55][56] to peralkylated species such as [B 12 Me 12 ] •-, 57 and to related OR substituted derivatives (R = CH 2 Ph, H). [58][59][60] The substituted 'hypercloso' compounds, typically generated by one-electron oxidation from dianionic closo precursors, are stabilized with electronegative substituents because neither Hal + nor R + or RO + are good leaving groups such as H + .…”

Section: Oligoborane Cluster Radicals [B N X N ] •-mentioning

confidence: 99%

Multidimensional potential of boron-containing molecules in functional materials

Kaim

Hosmane

2010

J Chem Sci

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Boron-containing molecular systems have received much attention under theoretical aspects and from the side of synthetic organic chemistry. However, their potential for further applications such as optically interesting effects such as Non-Linear Optics (NLO), medical uses for Boron Neutron Capture Therapy (BNCT), or magnetism has been recognised only fairly recently. Molecular systems containing boron offer particular mechanisms to accommodate unpaired electrons which may result in stable radicals as spin-bearing materials. Among such materials are organoboron compounds in which the prototypical electron deficient ( 10 B, 11 B) boron vs. carbon centers can accept and help to delocalise added electrons in a 2-dimensionally conjugated π system. Alternatively, oligoboron clusters B n X n k and the related carboranes or metallacarboranes are capable of adding or losing single electrons to form paramagnetic clusters with 3-dimensionally delocalised spin, according to combined experimental studies and quantum chemical calculations. The unique nuclear properties of 10 B are of therapeutic value if their selective transport via appended carbon nanotubes, boron nanotubes, or magnetic nanoparticles can be effected.

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Polyhedral Borane Free Radicals¹

Cited by 19 publications

References 2 publications

Hexaborate Cluster Radical Anions [B₆Hal_n Hal'_6-n]^.- and [B₆Hal₅R]^.-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy

Hexaborate Cluster Radical Anions [B₆Hal_n Hal'_6-n]^.- and [B₆Hal₅R]^.-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy

Supercarborane Radical Anions with 2n + 3 Electron Counts: A Combined Experimental and Theoretical Study

Multidimensional potential of boron-containing molecules in functional materials

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Polyhedral Borane Free Radicals1

Cited by 19 publications

References 2 publications

Hexaborate Cluster Radical Anions [B6Haln Hal'6-n].- and [B6Hal5R].-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy

Hexaborate Cluster Radical Anions [B6Haln Hal'6-n].- and [B6Hal5R].-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy

Supercarborane Radical Anions with 2n + 3 Electron Counts: A Combined Experimental and Theoretical Study

Multidimensional potential of boron-containing molecules in functional materials

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About

Polyhedral Borane Free Radicals¹

Hexaborate Cluster Radical Anions [B₆Hal_n Hal'_6-n]^.- and [B₆Hal₅R]^.-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy

Hexaborate Cluster Radical Anions [B₆Hal_n Hal'_6-n]^.- and [B₆Hal₅R]^.-(Hai, Hal' = CI, Br, I; R = H, alkyl). Chemical or Electrochemical Generation, Vibrational, UV-Vis and EPR Spectroscopy