NMR studies of boranes, carboranes and hetero-atom boranes

Todd, Lee J.; Siedle, A. R.

doi:10.1016/0079-6565(79)80001-1

Cited by 78 publications

(58 citation statements)

References 350 publications

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“…The data for 1 agree with those m easured previously [4,15]. The influence of the brom ine substituent in 2 on the 6 n B data is analo gous to th a t observed for carbaboranes C [9], Similarly, the presence of the B (6 ) -H group in 3 affects the <5n B values in the expected way [9,16]. The <3n B data of the pentaalkyl derivatives 2 and th e 1,3,4-triethyl derivative 11 are alm ost identical.…”

Section: Me3s Nc =C H + Et3bsupporting

confidence: 80%

Synthesis of Pentaalkyl-6-bromo-2,3,4,5-tetracarba-nido-hexaboranes(6)

Wrackmeyer

Glöckle

1996

Zeitschrift Für Naturforschung B

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2,3,4.5-Tetracarba-m'do-hexaboranes(6), Exchange Reactions, NMR Spectra Peralkylated 2,3,4,5-tetracarba-mdo-hexaboranes(6) 1 react with boron tribromide, BBr3, via selective exchange of the alkyl substituent in 6-position to give the corresponding new 6-bromo derivatives 2 in quantitative yield. The 6-iodo derivatives 2(1) can be prepared in the same way using BI3. Treatment of the carbaboranes 2 with Li E t3BH leads to the 1,2,3,4,5-pentaalkyl-2,3,4,5-tetracarba-/7/do-hexaboranes(6) 3. 1,3,4,6-Tetraethyl-2,3,4,5-tetracarbaw do-hexaborane(6) 4 reacts with BBr3 via degradation of the carbaborane cage to give E tB B r, and (Z)-l,4-bis [bis(dibromoboryl)]-3-hexene 5. A new bis(diethylboryl)-substituted dialkenyl(bromo)borane 8 was prepared, but attem pts failed to convert it into a 1-bromo-or 6-bromo-mdo-C4B2-carbaborane. Treatment of l,l-dialkyl-3-diethylboryl-4-ethylstannoles 9 with a large excess of BBr3 also affords 5, whereas 6-bromo-l,3,4-triethyl-2,3,4.5-tetracarbam do-hexaborane(6) 11 was isolated in low yield (<5%) from the reaction between 9 and BBr3 (slight excess).

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Section: Me3s Nc =C H + Et3bsupporting

confidence: 80%

Synthesis of Pentaalkyl-6-bromo-2,3,4,5-tetracarba-nido-hexaboranes(6)

Wrackmeyer

Glöckle

1996

Zeitschrift Für Naturforschung B

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“…species. [18,10] An extra resonance at d = + + 19.2 ppm, not coupled to any H, was also present that is the consequence of the removed BH vertex. It has been known for years that the partial degradation reaction on o-carborane derivatives is driven by a nucleophilic attack that can remove one of their BH units (B3 or B6), formally as BH [19] amines, [20] fluorides, [21] or phosphanes [22] have been used.…”

mentioning

confidence: 98%

“…[17] The 1 HA C H T U N G T R E N N U N G { 11 B}, H} NMR resonances for all the complexes featured similar patterns in the range from d = 2 to À15 ppm that agree with a closo cluster. [18] The dinuclear pyridyl compounds are stable in THF and CH 2 Cl 2 but are unstable in CH 3 OH because a copper metallic mirror was observed after keeping the complex in MeOH for several hours. species.…”

mentioning

confidence: 98%

Design of Dinuclear Copper Species with Carboranylcarboxylate Ligands: Study of Their Steric and Electronic Effects

Fontanet

Popescu

Fontrodona

et al. 2011

Chemistry A European J

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A series of new mononuclear and carboranylcarboxylate-bridged dinuclear copper(II) compounds containing the 1-CH(3)-2-CO(2)H-1,2-closo-C(2)B(10)H(10) carborane ligand (LH) has been synthesized. Reaction of different copper salts with LH at room temperature leads to dinuclear compounds of the general formula [Cu(2)(μ-L)(4)(L(t))(2)] (L(t) = thf (1), L(t) = H(2)O (1')). The reaction of 1 and 1' with different terminal pyridyl (py) ligands leads to the formation of a series of structurally analogous complexes by substitution of the terminal ligand thf or H(2)O (L(t) = py (2), p-CF(3)-py (3), p-CH(3)-py (4), pz (6), and 4,4'-bpy (7)), which maintain the structural Cu(2)(μ-O(2)CR)(4) core in the majority of the cases except for o-(CH(3))(2)-py, where a mononuclear compound (5) is exclusively obtained. These compounds have been characterized through analytical, spectroscopic (NMR, IR, UV-visible, ESI-MS) and magnetic techniques. X-ray structural analysis revealed a paddle-wheel structure for the dinuclear compounds, with a square-pyramidal geometry around each copper ion and the carboranylcarboxylate ions bridging two copper atoms in syn-syn mode. The mononuclear complex obtained with the o-(CH(3))(2)-py ligand presents a square-planar structure, in which the carboranylcarboxylate ligand adopts a monodentate coordination mode. The magnetic properties of the dinuclear compounds 1, 3, 4, and 6 show a strong antiferromagnetic coupling in all cases (J = -261 (1), -255 (3), -241 (4), -249 cm(-1) (6)). Computational studies based on hybrid density functional methods have been used to study the magnetic properties of the complexes and also to evaluate their relative stability on the basis of the strength of the bond between each Cu(II) and the terminal ligand.

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“…Die <5 n B-Werte der apicalen Bor-Atome (B(l)) (-44,2 bis -46,2) und der Basis-Bor-Atome (B(6)) ( + 17,8 bis -f 19,3) sind typisch für die Umgebung dieser Kerne [18]. Somit ermöglicht die n B-NMRSpektroskopie den einfachen Nachweis der Carborane bereits in Reaktionslösungen.…”

Section: Nb-nmr-spektroskopieunclassified

¹¹B- und ¹³C-NMR-Spektroskopie von nido-Hexaalkyl-2.3.4.5-tetracarbahexaboranen(6) / ¹¹B- und ¹³C-NMR Spectroscopy of nido-Hexaalkyl-2,3,4,5-tetracarbahexaboranes(6)

Wrackmeyer¹

1982

Zeitschrift Für Naturforschung B

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11B and 13C NMR data of peralkylated nido-2,3,4,5-tetracarbahexaboranes(6) are reported. Application of selective heteronuclear triple resonance experiments 13C{1H,11B} enables to assign the structures of various isomers. The magnitude of the coupling constants 1J(11B11B), 1J(13C11B) and 1J(13C13C) is in accord with expectations based on the conception of bonding in carboranes. The comparison of δ11B and δ13C data of the nido- 2,3,4,5-tetracarboranes(6) with δ13C-data of corresponding non-classical carbocations shows the influence of charge upon the nuclear shielding of carbon in the latter.

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NMR studies of boranes, carboranes and hetero-atom boranes

Cited by 78 publications

References 350 publications

Synthesis of Pentaalkyl-6-bromo-2,3,4,5-tetracarba-nido-hexaboranes(6)

Synthesis of Pentaalkyl-6-bromo-2,3,4,5-tetracarba-nido-hexaboranes(6)

Design of Dinuclear Copper Species with Carboranylcarboxylate Ligands: Study of Their Steric and Electronic Effects

¹¹B- und ¹³C-NMR-Spektroskopie von nido-Hexaalkyl-2.3.4.5-tetracarbahexaboranen(6) / ¹¹B- und ¹³C-NMR Spectroscopy of nido-Hexaalkyl-2,3,4,5-tetracarbahexaboranes(6)

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NMR studies of boranes, carboranes and hetero-atom boranes

Cited by 78 publications

References 350 publications

Synthesis of Pentaalkyl-6-bromo-2,3,4,5-tetracarba-nido-hexaboranes(6)

Synthesis of Pentaalkyl-6-bromo-2,3,4,5-tetracarba-nido-hexaboranes(6)

Design of Dinuclear Copper Species with Carboranylcarboxylate Ligands: Study of Their Steric and Electronic Effects

11B- und 13C-NMR-Spektroskopie von nido-Hexaalkyl-2.3.4.5-tetracarbahexaboranen(6) / 11B- und 13C-NMR Spectroscopy of nido-Hexaalkyl-2,3,4,5-tetracarbahexaboranes(6)

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¹¹B- und ¹³C-NMR-Spektroskopie von nido-Hexaalkyl-2.3.4.5-tetracarbahexaboranen(6) / ¹¹B- und ¹³C-NMR Spectroscopy of nido-Hexaalkyl-2,3,4,5-tetracarbahexaboranes(6)