Bis-amidocarbazolyl urea receptor for short-chain dicarboxylate anions

Abstract

Urea receptor 1 based on two (1-amino-8-amido-3,6-dichloro)carbazole units shows a strong association with dicarboxylate anions such as oxalate, malonate and succinate guests through multiple hydrogen bonds from the carbazole, urea and amide NH groups. (1)H NMR complexation studies exhibit high values of association constants in DMSO-d(6). X-ray structures of the 1 : 1 complexes of 1 with oxalate and malonate as their ditetrabutylammonium salts were obtained. A modelling study of the complex of receptor 1 with succinate (as its diTBA salt) showed a more reduced geometric complementarity than its homologue malonate.

1,8-Diamidocarbazoles: an easily tuneable family of fluorescent anion sensors and transporters

“…Please do not adjust margins Please do not adjust margins carboxylates by at least 2 orders of magnitude better than pyrrole bisamides in a very competitive solvent mixture: DMSO+0.5%H2O. Although the DADCC motif has been successfully used by us 14,15 and other research groups [16][17][18][19][20] to construct potent anion receptors and sensors, the full potential of this building block remains largely unexplored. For instance, the ability of diamidocarbazoles to facilitate transmembrane anion transport has never been investigated thus far.…”

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

“…Furthermore,( R)-Glu 2À is held by fewer HB interactions (2.8 AE 0.8) than the S enantiomer (3.3 AE 0.9;T able S6-2). Thed ifference in the interaction energies of the two diastereomeric complexes (DE int )w as (Table S6- 7), allowing as many as seven HB interactions to be established between the carboxylate groups and CH 3 OH (Table S6- 8). Compared to the [3]rotaxane,whose structure is rigidified and preorganised by the presence of both macrocycles,the free axle features aconformationally more flexible DC 2À binding cavity.Asaresult, the binding geometries of the diastereomeric complexes between axle 1 2+ and (S)/(R)-Glu 2À are very similar, such that the anion enantiomers are held together by equivalent numbers of XB interactions ((R)- In conclusion, we have reported the first chiral XB [3]rotaxane that can distinguish between DC 2À enantiomers and geometric isomers via the formation of distinct 1:1 stoichiometric sandwich binding complexes.Crucially,smaller anions (e.g., Cl À )that are unable to span the length between both macrocycle motifs are bound more weakly and exhibit significantly diminished fluorescence responses compared to DC 2À complexation.…”

“…Dicarboxylates (DC 2À )c onstitute al arge and structurally diverse class of anions that play crucial roles in biology and industry, [1] with some implicated as environmental pollutants (e.g.,o xalate). [2] Their biological importance has primarily driven the design and development of polytopic abiotic receptors that utilise hydrogen bonding (HB) interactions [3][4][5][6][7][8][9][10][11][12] and Lewis acidic metal centres [13,14] for binding and sensing. [15] However,D C 2À are highly challenging targets for selective recognition because of their hydrophilicity [16] and complex overall shapes,which arise from the diversity of spacer motifs between their anionic carboxylate termini.…”

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

“…Dicarboxylates (DC 2− ) constitute a large and structurally diverse class of anions that play crucial roles in biology and industry, with some implicated as environmental pollutants (e.g., oxalate) . Their biological importance has primarily driven the design and development of polytopic abiotic receptors that utilise hydrogen bonding (HB) interactions and Lewis acidic metal centres for binding and sensing . However, DC 2− are highly challenging targets for selective recognition because of their hydrophilicity and complex overall shapes, which arise from the diversity of spacer motifs between their anionic carboxylate termini.…”