A Chiral Halogen‐Bonding [3]Rotaxane for the Recognition and Sensing of Biologically Relevant Dicarboxylate Anions

Abstract

The unprecedented application of a chiral halogen‐bonding [3]rotaxane host system for the discrimination of stereo‐ and E/Z geometric isomers of a dicarboxylate anion guest is described. Synthesised by a chloride anion templation strategy, the [3]rotaxane host recognises dicarboxylates through the formation of 1:1 stoichiometric sandwich complexes. This process was analysed by molecular dynamics simulations, which revealed the critical synergy of halogen and hydrogen bonding interactions in anion discrimination. In addition, the centrally located chiral (S)‐BINOL motif of the [3]rotaxane axle component facilitates the complexed dicarboxylate species to be sensed via a fluorescence response.

Neutral Chiral Tetrakis‐Iodo‐Triazole Halogen‐Bond Donor for Chiral Recognition and Enantioselective Catalysis

“…[4] Differencesb etween XB and HB have been noted,i ncluding distinct selectivity patternst o-wardsL ewis bases and solvent effects. [4d, 5k-m] In the last few years,f urthera pplications of XBs have created great interest, providing new possibilities in selective recognition [5,[6][7][8][9] and organocatalysis. [10] However,X B-donors presents everal challenges that need to be overcome to effectively implement them for enantioselective applications: 1) the non-covalentX B-interactioni sh ighly directional (R-X-LB, % 1808); 2) in terms of chirali nductiono rr ecognition, the larger size of the halogen atom versus ah ydrogen results in higher distancesb etween the chiral backbone of the XB-donor and the bound substrate (LB);3 )although the more widely used charged XB-donors (such as iodo-imidazolium or triazolium salts) usually show significantly higher binding compared to their neutral derivatives, possible solubility issues and additional interactionsb etween their countera nions and the bounds ubstrate can interfere with the XB process itself.…”

“…[11] Consequently,o nly scarce applications of chiral XB-donors in enantioselective recognition and catalysish ave been reported so far.T hese can be categorized as follows:i )XBi nd ualc atalysis as as econdary interaction; [12] ii)the use of ap ositivelyc harged XB-donori nc ombination with ac hiral phosphate counteranion; [13] and iii)the more challenging application of XB as the primary determinant of selectivity.I nt he latter case, Kanger and co-workersa chieved the moderately selectiver ecognitiono f( S,S)-Takemoto'st hiourea catalyst withachiral monodentate iodo-triazolium salt. [14,15] The groups of Kubik [6] and Beer [7,9,[15][16][17] have significantly contributed to the fieldw ith bi-and multidentatei odo-triazole, [6,16] triazolium [17] BINOL-based and interlockedr otaxanes ystems [7,9] as chiral XB-donors, achieving moderate to good chiral recognition of mono-a nd dicarboxylates as well as phosphoric acids.M ore recently,t he group of Huber presented ac hiral bis(imidazolium) based XB-donort hat was able to discriminate betweene nantiomerso fachiral 1,2-diamine and induce enantioselectivity in aM ukaiyama aldol reaction. [18] However,t he designa nd synthesis of XB donor motifs for enantioselective recognition or catalysis remainsas ignificant challenge.…”

Rapid chiral analysis based on liquid-phase cyclic chemiluminescence

“…One of the major approaches to chirality sensing is based on the formation of diastereomeric complexes generated by intermolecular chiral-chiral interactions between a chiral host and chiral guest. 5,21,51,52 In order to explore the working mechanism of CCL for chiral discrimination, density functional theory and the B3LYP method in the Gaussian 09 program were employed to gain insight into the possible modes of interactions between R1 (or S1) and 1-phenylethanol enantiomers. Geometry optimization was performed using the basis set of LANL2DZ for cobalt atoms and 6-31G for other atoms.…”

“…[1][2][3] The simultaneous determination of the absolute conguration and enantiopurity of chiral substrates is highly signicant in the elds of synthetic, biological and pharmaceutical chemistry. [4][5][6] However, chiral analysis remains a great challenge because enantiomers have nearly identical physical properties. 7 In the past several decades, many effective methods have been developed for chiral analysis, such as gas chromatography, 8,9 high-performance liquid chromatography (HPLC), 10,11 capillary electrophoresis, [12][13][14] nuclear magnetic resonance (NMR) spectroscopy 7,[15][16][17] and mass spectrometry.…”

Chiral Bambusurils for Enantioselective Recognition of Carboxylate Anion Guests

“…[21] As carboxylates and sulfonates are attached to chiral centers of vast of biomolecules and also biologically active compounds there is great interesti nt he preparation of new supramolecular systems based on macrocyclesenabling chiral recognition of such compounds. [22][23][24][25][26][27] Herein, we present the first example of two chiral enantiomericallyp ure bambusuril macrocycles, and report on their ability to bind and differentiate enantiomers of chiral carboxylates.…”