Fluoride ion coordination-induced turn-on fluorescence of tailored N-methyl N-confused tripyrromonomethene analogues.

Structural isolation of two unprecedented AIEE/ACQ type fluorophores based on N-methyl N-confused tripyrromonomethene analogues exhibiting selective F- anion-coordination-induced-enhanced emission (ACIEE) with a detection limit of 10-7 M is reported. The intrinsic relation between molecular structures/molecular arrangements with (without) anion binding have been revealed at a deeper level via spectroscopic measurements and DFT level theoretical studies.

Neuroprotective Activity of a Novel Synthetic Rhodamine-Based Hydrazone against Cu2+-Induced Alzheimer's Disease in Drosophila.

A new rhodamine-based probe 3,5-di-tert-butylsalicylaldehyde rhodamine hydrazone (RHTB) has been synthesized and well characterized using spectroscopic techniques and single-crystal X-ray crystallography. Among several metal ions, it selectively detects Cu2+ ions as monitored by UV-Vis and emission spectral titrations. It displays "turn on" behavior owing to the opening of a spirolactum ring and the presence of 3,5-di-tert-butyl as an electron releasing group. Further, Cu2+ ions play a pivotal role in extracellular aggregation of Aß42 peptides. So far, we know probably that there are no promising drugs available in this regard. Hence, countering the Cu2+ ions by RHTB chelation against orally administered Cu2+ ion-induced neurotoxicity in the eye tissue of Drosophila expressing human Aß42 (amyloid-ß42) has been tested. The present study involves in vivo and in silico approaches. They reveal the therapeutic potential of RHTB against Cu2+ ion-induced Aß42 toxicity in Alzheimer's disease (AD) model of Drosophila.

An ensemble of Zn2+ with a rhodamine B-3-allylsalicylaldehyde hydrazone as novel photosensitive material: Photochromism, photopatterning, photoprinting and molecular logic gates.

An ensemble of Zn2+ with Rhodamine B-3-allylsalicylaldehyde hydrazone (1-Zn2+), has been synthesized and fully characterized using spectroscopic techniques. A solution of 1-Zn2+ in THF, displays color changes from light yellow to pink color in the presence UV light (λ, 405 nm). The process is reversible and owes to keto-enol tautomerism which allows the opening of spirolactam ring of rhodamine in the presence of UV light. It is corroborated by the appearance of a new peak at λmax = 554 nm. The ensemble, 1-Zn2+ embedded in the matrix of silica gel, displays photo patterning phenomena initiated by the conventional light sources including sunlight. It also displays photoprinting property with a laser pen (λ 405 nm) and has been displayed by a videography. The module 1-Zn2+ meets real challenges through a simple synthetic route, fast response, and as a binary data storage system with non-destructive optical identity.

A benzimidazolyl terpyridine-Fe2+ system and its recognition driven molecular model of a traffic light.

A new benzimidazolyl terpyridyl ligand (BIT) selectively detects Fe2+, F- and CN- ions in acetonitrile. The Fe2+ complex [Fe(H-BIT)2]·(ClO4)4 (1) displays the fast and selective detection of 2,4,6-trinitrophenol (TNP) with strong binding (log ß = 8.51 ± 0.24) and a low limit of detection (1.4 × 10-7 M) among several nitroaromatics. The color of complex 1 changes from purple to red, yellow, and green upon the separate addition of 2,4,6-trinitrophenol and tetrabutylammonium salts of fluoride and cyanide, respectively. The overall color changes thus display a model of a traffic light. The structures of BIT, 1 and [Fe(BIT)2]·(TNP)2 (2) have been well characterized using spectroscopic techniques and single crystal X-ray crystallography.