Synthesis and Properties of a Cationic Bidentate Lewis Acid

Lee, Min Hyung; Gabbaı̈, François P.

doi:10.1021/ic700360a

Cited by 95 publications

(48 citation statements)

References 26 publications

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“…49,51,52 These heteronuclear bifunctional boranes have been characterized by conventional means including 199 Hg NMR spectroscopy. In the case of 11, the 199 Hg NMR signal, which appears at 741.9 ppm, is split into a triplet of triplets as a result of coupling with fluorine nuclei of the pentafluorophenyl group ( 3 J Hg-F ) 499 Hz and 4 J Hg-F ) 165 Hz).…”

Section: B/hg Heteronuclear Multidentate Lewis Acidsmentioning

confidence: 99%

“…In water, the emission band is centered at 458 nm for [p-16] + and 433 nm for [o-16] +(Figure 10) giving rise to a distinct blue color, which can be detected with the naked eye at micromolar concentrations. In the case of [p-16] + , the blue emission is readily quenched upon addition of 1 equiv of cyanide, which binds to the boron center thereby disrupting the frontier orbitals (Figure 11).To verify whether the Coulombic effects could be used to increase the anion affinity of chelating bifunctional boranes, the heteronuclear B/Hg compound 12 was converted into the corresponding ammonium triflate salt[17]OTf by reaction with MeOTf (Scheme 10) 52. As shown by DFT calculations, conversion of the amino group into an ammonium group on going from 12 to [17] + results in a lowering of the mercury vacant orbitals, allowing them to mix more efficiently with the boron orbital.…”

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confidence: 99%

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Fluoride Ion Recognition by Chelating and Cationic Boranes

2009

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Because of the ubiquity of fluoride ions and their potential toxicity at high doses, researchers would like to design receptors that selectively detect this anion. Fluoride is found in drinking water, toothpaste, and osteoporosis drugs. In addition, fluoride ions also can be detected as an indicator of uranium enrichment (via hydrolysis of UF(6)) or of the chemical warfare agent sarin, which releases the ion upon hydrolysis. However, because of its high hydration enthalpy, the fluoride anion is one of the most challenging targets for anion recognition. Among the various recognition strategies that are available, researchers have focused a great deal of attention on Lewis acidic boron compounds. These molecules typically interact with fluoride anions to form the corresponding fluoroborate species. In the case of simple triarylboranes, the fluoroborates are formed in organic solvents but not in water. To overcome this limitation, this Account examines various methods we have pursued to increase the fluoride-binding properties of boron-based receptors. We first considered the use of bifunctional boranes, which chelate the fluoride anion, such as 1,8-diborylnaphthalenes or heteronuclear 1-boryl-8-mercurio-naphthalenes. In these molecules, the neighboring Lewis acidic atoms can cooperatively interact with the anionic guest. Although the fluoride binding constants of the bifunctional compounds exceed those of neutral monofunctional boranes by several orders of magnitude, the incompatibility of these systems with aqueous media limits their utility. More recently, we have examined simple triarylboranes whose ligands are decorated by cationic ammonium or phosphonium groups. These cationic groups increase the electrophilic character of these boranes, and unlike their neutral analogs, they are able to complex fluoride in aqueous media. We have also considered cationic boranes, which form chelate complexes with fluoride anions. Our work demonstrates that Coulombic and chelate effects are additive and can be combined to boost the anion affinity of Lewis acidic hosts. The boron compounds that we have investigated present a set of photophysical and electrochemical properties that can serve to signal the fluoride-binding event. We can also apply this approach to cyanide complexation and are continuing our investigations in that area.

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Section: B/hg Heteronuclear Multidentate Lewis Acidsmentioning

confidence: 99%

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confidence: 99%

Fluoride Ion Recognition by Chelating and Cationic Boranes

2009

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“…Studies of several groups have demonstrated that boron based receptors that are bidentate and cationic capitalize on both Coulombic and cooperative effects leading to a further enhancement of their F  affinity. Consequently, F  detection in aqueous media could be realized [37][38][39][40]. In order to recognize F  in water solution, Gabbaï et al [37][38][39][40] developed a number of cationic boranes (40-44 in Figure 12).…”

Section: Fluoride Detection In Aqueous Mediamentioning

confidence: 99%

“…Consequently, F  detection in aqueous media could be realized [37][38][39][40]. In order to recognize F  in water solution, Gabbaï et al [37][38][39][40] developed a number of cationic boranes (40-44 in Figure 12). These compounds were able to bind with F  in organic solvent/ water mixed solution with high sensitivity and selectivity.…”

Section: Fluoride Detection In Aqueous Mediamentioning

confidence: 99%

A class of fascinating optoelectronic materials: Triarylboron compounds

et al. 2010

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Triarylboron compounds are significant optoelectronic materials due to their excellent emissive and electron-transport properties, and could be applied in organic light-emitting diodes as emissive and/or electron-transport layers. Triarylboron compounds have vacant p  orbital and have received increasing interest as fluoride ion and cyanide ion sensors utilizing specific Lewis acid-base interaction. This review summarizes their structural characteristics, optical properties and applications in chemosensors for anions and optoelectronic devices developed in recent years and discusses the problems and prospects.

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“…However, we would like to acknowledge and cite some leading references on topics that have been put aside deliberately. These include principally, but not exclusively, the work on:·ferrocenylboranes (and other related compounds) and the study of the M-B interaction in these complexes; [12] group IV metallocenylboranes and the study of zwitterionic complexes in ZieglerNatta polymerization; [13] the hydroboration of olefin-containing metallocenes; [14] the electrophilic attack of dienes and alkyl groups by Lewis acids; [15] boryls, borylenes and other metal-bonded boron species; [16] some bidentate Lewis acids; [17] multimetallic species containing bridging boronates. [18] Coordination of Base-Free Amphoteric Ligands…”

Section: Introductionmentioning

confidence: 99%