Tuning Aqueous Supramolecular Polymerization by an Acid-Responsive Conformational Switch.

Besides their widespread use in coordination chemistry, 2,2'-bipyridines are known for their ability to undergo cis-trans conformational changes in response to metal ions and acids, which has been primarily investigated at the molecular level. However, the exploitation of such conformational switching in self-assembly has remained unexplored. In this work, the use of 2,2'-bipyridines as acid-responsive conformational switches to tune supramolecular polymerization processes has been demonstrated.

Interplay between H-Bonding and Preorganization in the Evolution of Self-Assembled Systems.

Cooperative π-π interactions and H-bonding are frequently exploited in supramolecular polymerization; however, close scrutiny of their mutual interplay has been largely unexplored. Herein, we compare the self-assembly behavior of a series of C - and C -symmetrical oligophenyleneethynylenes differing in their amide topology (N- or C-centered). This subtle structural modification brings about drastic changes in their photophysical and supramolecular properties, highlighting the reciprocal impact of H-bonding vs.

Real Time Imaging and Dynamics of Hippocampal Zn under Epileptic Condition Using a Ratiometric Fluorescent Probe.

Zinc, the essential trace element in human body exists either in the bound or free state, for both structural and functional roles. Insights on Zn distribution and its dynamics are essential in view of the fact that Zn dyshomeostasis is a risk factor for epileptic seizures, Alzheimer's disease, depression, etc. Herein, a bipyridine bridged bispyrrole (BP) probe is used for ratiometric imaging and quantification of Zn in hippocampal slices.

An Unsymmetrical Squaraine-Dye-Based Chemical Platform for Multiple Analyte Recognition.

The design of fluorescent molecular platforms capable of responding to multiple analytes is a topic of great interest. Herein, the use of a Zn -complexed unsymmetrical squaraine dye, Sq-Zn , as a chemical platform for recognizing structurally distinct analytes is reported. The squaraine ring is substituted on one side with a dipicolylamine unit, which acts as the metal ion receptor, whereas the other part of the molecule carries a dibutylaniline moiety, which is an electron donor.

Nanosheets of an Organic Molecular Assembly from Aqueous Medium Exhibit High Solid-State Emission and Anisotropic Charge-Carrier Mobility.

A π-conjugated amphiphilic diketopyrrolopyrrole (PDPP-Amphi) forms crystalline 2D supramolecular nanosheets in water when compared to that from methyl cyclohexane. These nanosheets exhibit high fluorescence quantum yield in the solid-state with anisotropic charge-carrier mobility of 0.33 cm V s .

A Three-Photon Active Organic Fluorophore for Deep Tissue Ratiometric Imaging of Intracellular Divalent Zinc.

Deep tissue bioimaging with three-photon (3P) excitation using near-infrared (NIR) light in the second IR window (1.0-1.4 μm) could provide high resolution images with an improved signal-to-noise ratio.

Chain folding controlled by an isomeric repeat unit: helix formation versus random aggregation in acetylene-bridged carbazole-bipyridine co-oligomers.

An unprecedented, positional effect of the isomeric repeat unit on chain folding in donor–acceptor-linked oligomers, which contain alternating bipyridine and carbazole moieties that are connected through an acetylinic linkage, is reported. 4,4′-Linked oligomer 1 adopts an intrachain helical conformation (CD-active) in CHCl3/MeCN (20:80 v/v), whereas oligomer 2, which contains an isomeric 6,6′-linkage, forms interchain randomly coiled aggregates (CD-inactive). The substitution position plays a significant role in controlling the variations in electronic effects and dipole moments around the bipyridyl moiety, which are responsible for this observed phenomenon.

Heteroaromatic donors in donor-acceptor-donor based fluorophores facilitate zinc ion sensing and cell imaging.

The excited state intra molecular charge transfer (ICT) property of fluorophores has been extensively used for the design of fluorescent chemosensors. Herein, we report the synthesis and properties of three donor–π-acceptor–π-donor (D–π-A–π-D) based molecular probes BP, BT and BA. Two heteroaromatic rings, pyrrole (BP), and thiophene (BT) and a non-heteroaromatic ring N-alkoxy aniline (BA) were selected as donor moieties which were linked to a bipyridine binding site through a vinylic linkage.