Multiple Multidentate Halogen Bonding in Solution, in the Solid State, and in the (Calculated) Gas Phase

Jungbauer, Stefan H.; Schindler, Severin; Herdtweck, Eberhardt; Keller, Sandro; Huber, Stefan M.

doi:10.1002/chem.201502043

Cited by 44 publications

(46 citation statements)

References 104 publications

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“…This involvement was further corroborated by the fact that addition of a chloride salt led to complete inhibition of the catalytic activity, presumably by a strong coordination to the iodine substituents. The binding was then studied in more detail in solution ( K b =7.5×10 4 m −1 in THF for the para ‐substituted bidentate catalyst and chloride) and in the solid state (Figure ) …”

Section: Halide Abstraction By Halogen Bondingmentioning

confidence: 99%

Halogen Bonding in Organic Synthesis and Organocatalysis

Bulfield

Huber

2016

Chemistry A European J

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535

348

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Halogen bonding is a noncovalent interaction similar to hydrogen bonding, which is based on electrophilic halogen substituents. Hydrogen-bonding-based organocatalysis is a well-established strategy which has found numerous applications in recent years. In light of this, halogen bonding has recently been introduced as a key interaction for the design of activators or organocatalysts that is complementary to hydrogen bonding. This Concept features a discussion on the history and electronic origin of halogen bonding, summarizes all relevant examples of its application in organocatalysis, and provides an overview on the use of cationic or polyfluorinated halogen-bond donors in halide abstraction reactions or in the activation of neutral organic substrates.

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Section: Halide Abstraction By Halogen Bondingmentioning

confidence: 99%

Halogen Bonding in Organic Synthesis and Organocatalysis

Bulfield

Huber

2016

Chemistry A European J

Self Cite

535

348

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“…21)w ith the ability to form multidentate XBs at two identical sides of the receptor (Figure 13). [59] Acomprehensive study of the binding properties in the solid state revealed an anti-cooperative behavior of these two binding sides,n amely,t he tridentate binding on one side of the molecule and binding with reduced denticity on the remaining side.T he negative cooperativity was further revealed by the characteristic biphasic shape of the ITC data indicating two successive binding events with different binding affinities (K 1 , K 2 )i nsolution. Besides the tridentate system, the Beer research group also synthesized the first neutral tetradentate XB donor foldamers 22 (X = I).…”

Section: Multidentate Receptorsmentioning

confidence: 99%

Halogen Bonding in Solution: Anion Recognition, Templated Self‐Assembly, and Organocatalysis

2018

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The halogen bond is a supramolecular interaction between a Lewis-acidic region of a covalently bound halogen and a Lewis base. It has been studied widely in silico and experimentally in the solid state; however, solution-phase applications have attracted enormous interest in the last few years. This Minireview highlights selected recent developments in halogen bond interactions in solution, with a focus on the use of receptors based on halogen bonds in anion recognition and sensing, anion-templated self-assembly, as well as in organocatalysis.

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“…[22] Theoretical calculations have also been widely used to investigate the nature and applications of XB. [1][2][3][4][23][24][25][26][27][28] Even though many levels of theory have estimated the strength of al ong list of XBs to be in the range of 0.04-1.20 eV, [29] they have hardly been investigated experimentally.T here is ad earth of experimental determinations of halogen bond strengths.G as-phase measurements of isolated systems has unique advantages to provide XB strengths that are in undisturbed local environments.I nt he current paper,w e present ag as-phase,m ass spectrometric and photoelectron spectroscopic study of the archetypical Br À -bromotrichloromethane complexes.I nC Cl 3 Br,t he Br atom exhibits as ignificant s-hole,m aking it ag ood XB donor.T he bromine anion is necessary to act as anegatively-charged non-covalent binding partner and to be able to apply the anion photoelectron spectroscopy.W em easured the photoelectron spectra of Br À (CCl 3 Br) 0-2 ,a nd utilized density functional theory (DFT) calculations to compare with our experimental values, to visualize the XBs,a nd to provide thermodynamic rationales to understand the formation of these complexes.Details of the experimental and theoretical methods are provided in the Supporting Information. Thep hotoelectron spectra of Br À and Br À (CCl 3 Br) taken with 266 nm (4.66 eV) laser and Br À (CCl 3 Br) 2 taken with 193 nm (6.42 eV) laser are presented in Figure 1.…”

mentioning

confidence: 99%

Spectroscopic Measurement of a Halogen Bond Energy

et al. 2019

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Halogen bonding (XB) has emerged as an important bonding motif in supramolecules and biological systems. Although regarded as astrong noncovalent interaction, benchmark measurements of the halogen bond energy are scarce. Here,acombined anion photoelectron spectroscopya nd density functional theory (DFT) study of XB in solvated Br À anions is reported. The XB strength between the positivelycharged s-hole on the Br atom of the bromotrichloromethane (CCl 3 Br) molecule and the Br À anion was found to be 0.63 eV (14.5 kcal mol À1 ). In the neutral complexes,B r(CCl 3 Br) 1,2 ,t he attraction between the free Br atom and the negatively charged equatorial belt on the Br atom of CCl 3 Br,w hich is as econd type of halogen bonding,w as estimated to have interaction strengths of 0.15 eV (3.5 kcal mol À1 )a nd 0.12 eV (2.8 kcal mol À1 ).Even though they are generally regarded as electron withdrawing groups,a lready covalently-bonded halogen atoms can in addition interact attractively and directionally by an on-covalent bond to neighbor nucleophiles such as lone pairs and anions. [1][2][3][4] This noncovalent interaction was first referred to as "halogen bonding" (XB) by Dumas and coworkers in 1976. [5,6] Halogen atoms have positive electrostatic potential regions on the opposite end of their s bond due to polarizability;m oreover,t he equatorial sides of these atoms exhibit negative electrostatic potential belts. [7,8] Thep ositive facial site was termed as "s-hole" by Politzer et al. in 2007, [9] although, clearly it is only apositive partial charge present at this site and no full electron is missing in any orbital. Thesize of the s-hole depends on the polarizability of the halogen atom, that is,I> Br > Cl > F, but it can also be tuned by other highly electron-withdrawing functional groups in the molecule. [2] While the positively-charged s-hole interacts with nucleophiles,the negatively-charged equatorial belt interacts with electrophiles,r esulting in two categories of XB inter-actions. [1] XB has rapidly expanded into applications such as crystal engineering. [10][11][12][13][14] It also has provoked the survey of biological structures,w here XB has been found to stabilize inter-a nd intramolecular interactions that can further affect ligand binding,p rotein folding,a nd enzymatic reactions. [15] While presence of XB interactions in the condensed-phase materials and biological chemistry is well known, experimental investigations of XB in the gas phase have been scarce. Nevertheless,t echniques such as molecular beam scattering, [16] rotational spectroscopy, [17][18][19] blackbody infrared radiative dissociation [20] and ion-mobility mass spectrometry have provided significant insight. [21] More recently,o ur group reported the stabilization of otherwise unstable anions by XB using gas-phase anion photoelectron spectroscopy. [22] Theoretical calculations have also been widely used to investigate the nature and applications of XB. [1][2][3][4][23][24][25][26][27][28] Even though many levels of theory have estimated th...

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Multiple Multidentate Halogen Bonding in Solution, in the Solid State, and in the (Calculated) Gas Phase

Cited by 44 publications

References 104 publications

Halogen Bonding in Organic Synthesis and Organocatalysis

Halogen Bonding in Organic Synthesis and Organocatalysis

Halogen Bonding in Solution: Anion Recognition, Templated Self‐Assembly, and Organocatalysis

Spectroscopic Measurement of a Halogen Bond Energy

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