D. Amilan Jose

Rugby-Ball-Shaped Sulfate−Water−Sulfate Adduct Encapsulated in a Neutral Molecular Receptor Capsule

We report a tren-based tris(urea) receptor molecule that shows preferential binding with sulfate/phosphate anions. The receptor acts as a neutral molecular capsule, within which a unique sulfate-(H(2)O)(3)-sulfate adduct is encapsulated.

A density functional study towards substituent effects on anion sensing with urea receptors

AbstractEffects of substituents on anion binding in different urea based receptors have been examined using density functional (B3LYP/6-311+G**) level of theory. The complexes formed by a variety of substituted urea with a halide anion (fluoride) and an oxy-anion (acetate) have been calculated. The stronger complexes were predicted for receptors with fluoride ion than that of acetate ion, however, in water the preference was found to be reversed. The pKa calculations showed the preferred sites of deprotonation for positional isomers, while interacting with anions. The position of the substituent in the receptor, however, could change the preferred sites of deprotonation compared to the site predicted with pKa values. FigureThe substituent effects on anion binding towards different urea receptors have been examined by DFT with B3LYP/6-311+G** level of theory.

First snapshot of a nonpolymeric hydrogelator interacting with its gelling solvents

A pyridyl urea based low molecular weight supramolecular hydrogelator has been synthesized; crystallized from its gelling solvents, the single crystal structure of the gelator molecule interacting with its gelling solvents reported herein is the first example in the literature.

Reversible Colorimetric Sensor for Moisture Detection in Organic Solvents and Application in Inkless Writing

Colorimetric sensors based on Sudan-III (1) and Alizarin red S (2) have been developed for the detection of a trace amount of water in organic solvents such as THF, acetone, acetonitrile, and DMSO. The deprotonated (anionic) forms of 1 and 2 namely 1.F and 2.F are reprotonated by using a trace amount of water. Deprotonation of 1 and 2 was obtained by using fluoride anion. Test papers of 1.F and 2.F in organic solvents with and without moisture showed dramatic changes in color. Receptor 1.F exhibits high sensitivity for water in acetone and THF with the detection limit as low as 0.0042 and 0.0058 wt %. Remarkably, probes 1.F and 2.F are reversible in nature both in solution and in test strips. 1.F and 2.F are reversible and reusable for sensing moisture in the organic solvents with high selectivity, high sensitivity, and fast response. The reversible moisture sensor 1.F has also been used for application in inkless writing.

Generation of nanostructures by the aggregation of porphyrin derivatives with long alkane chain in mix-solvent

Controlled aggregation of tetrakis-(4-(hexadecyl oxy)-phenyl) porphyrin and its copper(II)-complex was studied in mix-solvent system at room temperature. Structure of the aggregates was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and UV-visible spectroscopy. TEM results indicated the formation of organized nanostructures from the porphyrin derivative and its corresponding copper(II)-complex. XRD results showed that the bulk and nanostructured free porphyrin derivatives had the similar crystalline morphology. UV-visible-NIR spectroscopic data showed broad red-shifted Soret band, indicating JJ aggregation among the monomer units. Conjugate effect of lateral pipi interaction among the tetrapyrrole cores and hydrophobic interaction among the long alkane chains substituted in the peripheral phenyl rings is believed to lead to the organized nanostructures. Effect of solvent ratio on the aggregate structure is also revealed.