Bis- and tris(amidine)fluoroboron cations and mixed tetrahaloborate anions: NMR studies of mixed boron trihalide adduct redistribution reactions involving amidines as strong nitrogen bases

Hartman, J. Stephen; Yuan, Zheng; Fox, Arnold; Nguyen, Thi Ngoc Anh

doi:10.1139/v96-242

Cited by 21 publications

(15 citation statements)

References 30 publications

(35 reference statements)

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“…Principally, equilibration by halide exchange may lead to [BF 4 ] – : 4[BHalF 3 ] – [lrarr2] 3[BF 4 ] – + <[BHal 4 ] – >. We did not obtain NMR spectroscopic results, which agree with the reported data of [BF n Hal 4– n ] – (Hal = Cl, Br; n = 0–3) 16,17…”

Section: Introductionsupporting

confidence: 81%

Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal₂ (Hal = F, Cl, Br), “BrF” (BrF₃–Br₂ 1:1), and ICl

Bardin

Adonin

Frohn

2011

Zeitschrift anorg allge chemie

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Reactions of [Bu 4 N][RBF 3 ] [R = C n F 2n+1 CF=CF (cis, trans), CF 2 =CF, CF 2 =C(CF 3 ), trans-C 4 H 9 CF=CF, trans-C 6 H 5 CF=CF, C 4 H 9 CH=CH (cis, trans), CF 3 CϵC, and C 4 H 9 CϵC] with chlorine, bromine, BrF 3 + Br 2 (as equivalent of "BrF"), and ICl in solution (CH 2 Cl 2 , CHCl 3 , CF 3 CH 2 CF 2 CH 3 ) led to 1,2-addition of halogen and/ or replacement of boron by halogen (halodeboration). The reaction of [Bu 4 N][CF 3 CϵCBF 3 ] with less than equimolar amounts of diluted fluorine (5 %) in 1,1,1,3,3-pentafluorobutane (PFB) showed only [Bu 4 N][CF 3 CF 2 CF 2 BF 3 ] as fluorine addition product besides extensive Scheme 5. Scheme 6. Scheme 7.Reaction of K[CF 2 =CFBF 3 ]: Chlorine (4.5 mmol) was bubbled into a stirred suspension of K[CF 2 =CFBF 3 ] (173 mg, 0.92 mmol) in CH 2 Cl 2

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Section: Introductionsupporting

confidence: 81%

Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal₂ (Hal = F, Cl, Br), “BrF” (BrF₃–Br₂ 1:1), and ICl

Bardin

Adonin

Frohn

2011

Zeitschrift anorg allge chemie

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“…(This method is not successful if B-Cl or B-Br bonds are present, since cations containing C1 or Br are much more susceptible to hydrolysis.) The isolation of doubly charged cations and mixed-donor cations will be reported elsewhere (12 …”

Section: Isolation Of D2bf2+ Saltsmentioning

confidence: 99%

Bis(pyridine)difluoroboron, tris(pyridine)fluoroboron, and other (pyridine)haloboron cations. A systematic NMR study

Farquharson¹,

Hartman²

1996

Can. J. Chem.

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Abstract:The adducts pyrBF,Br and pyrBFBr, (pyr = pyridine) form fluoroboron cations by displacement of Br-by excess pyridine, the ease of cation formation being pyr,BFc >>pyr,BFBr+ > > p y r 3~~2 + .C1-can be displaced from pyrBF,Cl and pyr.BFCl,, but much less readily, to form pyr,BFc, pyr2BFC1+, and, under forcing conditions, a few percent of p y r ,~~' + .Nonfluorine-containing mixed boron trihalide adducts of pyridine also form haloboron cations by heaviest-halide-ion displacement, for example pyrBC11, giving pyr,BClI+, the ease of displacement always being I-> Br-> C1-, and displacement always occurring more readily from mixed boron trihalide adducts than from unmixed-halogen adducts. The mechanistic implications of this are discussed. ortho Substituents greatly reduce the ability of pyridine to displace heavy halide ion, so 2-methylpyridine gives 2-Mepyr,BF: and 2-Mepyr,BFBr+ but not 2-Mepyr,BFCl+ or 2 -~e~~r ,~~' + , while 2,6-dimethylpyridine does not form any haloboron cations. '9 spin-lattice relaxation times of the fluoroboron cations are much shorter than those of neutral boron trihalide adducts in the same solution, and provide a further diagnostic test for their presence.Key words: fluoroboron cations, pyridines, mixed boron trihalide adducts, fluorine-19 NMR, boron-11 NMR.RCsumC : Les adduits pyrBF,Br et pyr.BFBr, (pyr = pyridine) forment des cations du fluorobore par dkplacement de B r par l'excks de pyridine; la facilitk de formation du cation est la suivante : pyr,BF,+ >>pyr,BFBr+ > > p y r 3~~2 + . I1 est possible de dkplacer le C1-des adduits pyr.BF,Cl et pyrBFCl,, pour former les pyr,BFc, pyr,BFCl+, et en for~ant les conditions quelques pour cents du p y r 3~~' + , mais la rkaction est beaucoup plus lente. Les adduits de la pyridine avec des trihalogknures mixtes du bore ne contenant pas de fluor forment aussi des cations halobores par le dkplacement de l'halogene le plus lourd; par exemple, le pyr.BC11, conduit au pyr,BClI+, la facilitk de dkplacement est I-> B r > C1-et le dkplacement se fait toujours plus facilement 8 partir d'adduits trihalogknures mixtes du bore qu'8 partir d'adduits non melanges d'halogknures de bore. On discute des implications mkcanistiques de ces rksultats. Les substituants ortho ralentissent beaucoup la facilitk de la pyridine 8 dkplacer les ions halogknures lourds; ainsi, la 2-mkthylpyridine conduit aux 2-Mepyr,BF,+ et 2-Mepyr,BFBr+, mais pas aux 2-Mepyr,BFClf ou 2 -~e~~r ,~~' + alors que la 2,6-dimkthylpyridine ne forme aucun cations halobore. Les temps de relaxation spin-rkseau du ' 9~ dans les cations du fluorobore sont beaucoup plus courts que ceux des adduits trihalogknures de bore neutres dans la m&me solution et ils fournissent une mkthode supplkmentaire pour diagnostiquer leur presence.Mots clks : cations du fluorobore, pyridines, adduits des trihalogknures mixtes du bore, RMN du 1 9~, RMN du "B.[Traduit par la rkdaction]

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“…The 11 B NMR of RN(Bpin)CH 2 CH 2 CH 2 Bpin (where R = H or Bpin) shows a peak at 25 ppm corresponding to the B-N bond and a resonance at 33 ppm for the new B-C bond. No appreciable intramolecular interactions are observed in these molecules as the boron atoms appear to be three-coordinate (40,48). This result is consistent with previous NMR data on related NH 2 CH 2 CH 2 CH 2 B(OH) 2 •HCl which shows a peak in the 11 B NMR at 32.6 ppm (49).…”

Section: Resultsmentioning

confidence: 97%

Rhodium-catalyzed hydroborations of allylamine and allylimines<sup>1</sup>

Vogels¹,

O’Connor²,

Phillips³

et al. 2001

Rev. Can. Chim.

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The in situ rhodium-catalyzed addition of catecholborane (HBcat, cat = 1,2-O 2 C 6 H 4) and pinacolborane (HBpin, pin = 1,2-O 2 C 2 Me 4) to allylamine, allylimine, 2-and 4-vinylpyridines, and a thienyl imine has been examined using multinuclear NMR spectroscopy. Although reactions of allylamine (H 2 NCH 2 CH=CH 2) and HBcat gave complex product distributions arising from competing dehydrogenative borylation pathways, addition of HBpin to allylamine using a rhodium catalyst afforded only products arising from hydroboration (RN(Bpin)CH 2 CH 2 CH 2 Bpin, where R = H, Bpin) and hydrogenation (RN(Bpin)CH 2 CH 2 CH 3). Hydroboration of allylimines (RHC=NCH 2 CH=CH 2 , R = Ar) with HBcat occurs initially at the more reactive imine functionality to give unsaturated borylamines (RCH 2 N(Bcat)CH 2 CH=CH 2). Further reaction with HBcat gives varying amounts of hydroboration products RCH 2 N(Bcat)CH 2 CH 2 CH 2 Bcat and RCH 2 N(Bcat)CH 2 CH(Bcat)CH 3 as well as the diboration product RCH 2 N(Bcat)CH 2 CH 2 CH(Bcat) 2 , depending on the choice of catalyst. Reactions with related unsaturated pyridine derivatives are complicated by extensive degradation, which can be avoided by coordination of the pyridine nitrogen to a Lewis acid. The first examples of metal-catalyzed hydroboration of imines using HBpin are also reported.

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Bis- and tris(amidine)fluoroboron cations and mixed tetrahaloborate anions: NMR studies of mixed boron trihalide adduct redistribution reactions involving amidines as strong nitrogen bases

Abstract: [Traduit par la rkdaction]

Cited by 21 publications

References 30 publications

Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal₂ (Hal = F, Cl, Br), “BrF” (BrF₃–Br₂ 1:1), and ICl

Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal₂ (Hal = F, Cl, Br), “BrF” (BrF₃–Br₂ 1:1), and ICl

Bis(pyridine)difluoroboron, tris(pyridine)fluoroboron, and other (pyridine)haloboron cations. A systematic NMR study

Rhodium-catalyzed hydroborations of allylamine and allylimines<sup>1</sup>

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Bis- and tris(amidine)fluoroboron cations and mixed tetrahaloborate anions: NMR studies of mixed boron trihalide adduct redistribution reactions involving amidines as strong nitrogen bases

Abstract: [Traduit par la rkdaction]

Cited by 21 publications

References 30 publications

Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal2 (Hal = F, Cl, Br), “BrF” (BrF3–Br2 1:1), and ICl

Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal2 (Hal = F, Cl, Br), “BrF” (BrF3–Br2 1:1), and ICl

Bis(pyridine)difluoroboron, tris(pyridine)fluoroboron, and other (pyridine)haloboron cations. A systematic NMR study

Rhodium-catalyzed hydroborations of allylamine and allylimines<sup>1</sup>

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Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal₂ (Hal = F, Cl, Br), “BrF” (BrF₃–Br₂ 1:1), and ICl

Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal₂ (Hal = F, Cl, Br), “BrF” (BrF₃–Br₂ 1:1), and ICl