Design, synthesis, and self-assembling properties of novel triazolophanes

Supersensitive Detection of Anions in Pure Organic and Aqueous Media by Amino Acid Conjugated Ellman's Reagent

The last few decades witnessed a remarkable advancement in the field of molecular anion receptors. A variety of anion binding motifs have been discovered, and large number of designer molecular anion receptors with high selectivity are being reported. However, anion detection in an aqueous medium is still a formidable challenge as evident from only a miniscule of synthetic systems available in the literature. We, herein, report 5,5'-dithio-bis(2-nitrobenzoic acid) (Ellman's reagent) appended with amino acids as supersensitive anion sensors that can detect F^- and H₂PO₄^- ions in both aqueous as well as organic media. Interestingly, the sensors showed a dual response to anions, viz., chromogenic response in organic medium and electrochemical response in aqueous solutions. Various spectroscopic techniques such as UV-vis and ¹H NMR are used to investigate the binding studies in acetonitrile, whereas electrochemical methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) are employed to explore the anion binding in water. The host-guest complex stoichiometry and binding constants are calculated using the BindFit software. The geometry of host-guest complex has been optimized by the density functional theory (DFT) method. These molecules are versatile sensors since these function in both water and acetonitrile with extremely low limit of detection (LOD) up to 0.07 fM and limit of quantification (LOQ) up to 0.23 fM. To our knowledge, the present system is the first example of a sensor that can detect the lowest concentration of anions in water quantitatively. The minimalistic design strategy presented here opens up the innumerable possibilities for designing dual anion sensors in a one fell swoop.

Artificial miniaturized luminescent materials based on perylene-covered glass surfaces

Cu(i)-Catalyzed 1,3-dipolar cycloaddition was used to construct a luminescent monolayer for an ICT-showing pyrrolidino-perylene association (5PMI) on glass surfaces, which represents a rare perylene chromophore, to date, anchored to a solid surface.

Spontaneous vesiculation: a mechanistic insight from the study of hybrid peptide molecules

We report a series of hybrid peptide molecules that display spontaneous vesiculation. A closer look at their vesicle formation revealed a toroidal intermediate en route to the final vesicular form.

Synthesis of bis(propargyl) aromatic esters and ethers: a potential replacement for isocyanate based curators

This study reports the synthesis and characterization of a novel class of non-isocyanate curing agents based on bis-propargyl aromatic esters 2a–e and ethers 4a–c.

Morphology engineering: dramatic roles of serine and threonine in supramolecular assembly

Macrocycles containing serine self-assembled into fibres, while threonine induced vesicular self-assembly. Macrocycles with serine can be driven to form vesicular assembly by incorporating a non-planar spacer.

Crystal structure of 1-(4-fluoro-phen-yl)-4-(4-meth-oxy-phen-yl)-1H-1,2,3-triazole

In the title compound, C15H12FN3O, the triazole ring forms dihedral angles of 30.57 (8) and 21.81 (9)° with the fluoro-substituted and meth-oxy-substituted benzene rings, respectively. The dihedral angle between the benzene rings is 51.53 (7)°. In the crystal, π-π inter-actions between the triazole rings [centroid-centroid seperations = 3.774 (2) and 3.841 (2) Å] form chains along [010].

Bis(carbamoylmethylphosphine oxide) ligands fixed on the arene core via 1,2,3-triazole linkers: novel effective extractants for palladium, lanthanides and actinides

The extraction of U(vi) and Th(iv) from 3 M HNO₃ solutions with 0.01 M solutions of extractants 1–8 in 1,2-dichloroethane.

Tris(triazole) tripodal receptors as selective probes for citrate anion recognition and multichannel transition and heavy metal cation sensing

The preparation and binding properties towards citrate anions and cations of two three-armed triazole based receptors are described.

Self-assembly of lipidated pseudopeptidic triazolophanes to vesicles

We have transformed the amino acid serine to 32-membered lipidated cyclophanes employing CuAAc reaction. These serine-based lipidated triazolophanes assemble to sturdy and robust vesicles.

Discovery of anion–π interactions in the recognition mechanism of inorganic anions by 1,2,3-triazolium rings

The simultaneous action of two noncovalent interactions in solution, hydrogen-bonding and anion–π, resulted in a selective receptor for HP₂O₇³⁻ anions.

Macrocyclic drugs and synthetic methodologies toward macrocycles

Macrocyclic scaffolds are commonly found in bioactive natural products and pharmaceutical molecules. So far, a large number of macrocyclic natural products have been isolated and synthesized. The construction of macrocycles is generally considered as a crucial and challenging step in the synthesis of macrocyclic natural products. Over the last several decades, numerous efforts have been undertaken toward the synthesis of complex naturally occurring macrocycles and great progresses have been made to advance the field of total synthesis. The commonly used synthetic methodologies toward macrocyclization include macrolactonization, macrolactamization, transition metal-catalyzed cross coupling, ring-closing metathesis, and click reaction, among others. Selected recent examples of macrocyclic synthesis of natural products and druglike macrocycles with significant biological relevance are highlighted in each class. The primary goal of this review is to summarize currently used macrocyclic drugs, highlight the therapeutic potential of this underexplored drug class and outline the general synthetic methodologies for the synthesis of macrocycles.

Nanometer-sized reactor--a porphyrin-based model system for anion species

Although many cagelike molecules can create a catalytic environment for promoting chemical reactions, the construction of receptors that can host anionic species and sensitize their reaction is novel. Here we report the photochemically induced dimerization of the anion radicals of TCNQ (7,7,8,8-tetracyano-para-quinodimethane) in organic solvent under aerobic conditions when they are encapsulated inside a cationic photoactive receptor. There is clear evidence for a rate increase of over two orders of magnitude, photosensitization of the host, and demonstrated turnover of the catalyst.