Sunlight-induced degradation of squarazine-based cyanide complex through imine CN free rotation: Sensing, binding and degradation studies of anionic complex.

Sunlight-induced degradable squarazine based electron deficient receptor 3,4-bis((E)-2-((perfluorophenyl)methylene)hydrazinyl)cyclobut-3-ene-1,2-dione, L has been reported here. Naked-eye colorimetric analysis, UV-Vis, IR and H, 19F, P-NMR spectrometric results show that this receptor L high affinity with cyanide anion. The strength of the receptor L towards colorimetrically responded anions are calculated by UV-Vis spectrometric titrations and it is found to be 9.

Anion-binding-induced selective aggregation and self-degradation: Influence of positional isomerism on the anion selectivity and mode of binding of an imine-based receptor.

Imine based positional isomers (8E)-N-(4-((E)-(perfluorophenylimino)methyl)benzylidene)-2,3,4,5,6-pentafluorobenzenamine, L and (10E)-N-(3-(E-Perfluorophenylimino)methyl)benzylidene)-2,3,4,5,6-pentafluorobenzenamine, L have been designed, and synthesized by functionalizing two electron deficient aromatic moieties at the para-para'/ortho-ortho' positions in the phenyl core of the L and L respectively. The responses of L and L towards various anionic species are examined. The positional isomers L and L differs not only by showing distinguishable color change upon addition of anions but also differentiates themselves by the way of self-assembling together upon binding with cyanide anion.

Characterizing Lomerizine metabolites in camel urine: High-resolution mass spectrometry method development and validation for enhanced doping control.

Rationale: Lomerizine (LMZ) is an antimigraine drug that works as a calcium channel blocker and has selective effects on the central nervous system. It is metabolized into trimetazidine (TMZ), which is a prohibited substance owing to its performance-enhancing effects in both human and animal sports. Effective doping control measures are imperative to distinguish the source of TMZ in samples to ensure integrity and fairness of the sport, therefore a comprehensive analysis of LMZ metabolites is essential to identify potential biomarkers in camel urine for effective doping control.

Fluorescence Sensor for Water in Organic Solvent Using Graphene Oxide- Rhodamine B and Cucurbit[7]uril.

Detection of water in organic solvents gained much importance as these solvents have been used as a medium for conducting organic reactions and water was considered as an inhibitor, when it is present in the reaction medium. There are number of methods available to measure the water content in organic solvents, however, such methods are time consuming and expensive. Here, we developed a facile method for detecting water in organic solvents using an inexpensive fluorescent probe - Rhodamine B decorated Graphene oxide (RBGO).

Pyrene-Hydrazone-π···Hole Coupled Turn-on Fluorescent and Naked- Eye Colorimetric Sensor for Cyanide: Role of Homogeneous π-Hole Dispersion in Anion Selectivity.

A pyrene based probe associated with π···hole - hydrazone as one of the recognizing elements is synthesized and its turn in to a selective colorimetric and turn-on fluorescent sensor, (L) for cyanide anion. This chemo sensor show high selectivity towards cyanide anion through photo electron transfer (PET) mechanism. The binding strength and sensitivity of the chemo sensor L towards cyanide are found to be 2.

Electrochemiluminescent Chiral Discrimination with a Pillar[5]arene Molecular Universal Joint-Coordinated Ruthenium Complex.

A bicyclic pillar[5]arene derivative fused with a bipyridine side ring, a so-called molecular universal joint (MUJ), was synthesized, and the pair of enantiomers was resolved by high-performance liquid chromatography enantioresolution. The electrochemiluminescent detection based on the ruthenium complex of the enantiopure MUJ showed excellent chiral discrimination toward certain amino acids.

Anion-binding-induced and reduced fluorescence emission (ABIFE & ABRFE): A fluorescent chemo sensor for selective turn-on/off detection of cyanide and fluoride.

A new hydrazine based π-hole assisted, electron deficient turn-on/off fluorescent and colorimetric sensor L with anion-binding induced/reduced fluorescent emission (ABIFE & ABRFE) has been designed and synthesized. The prepared sensor L exhibited excellent turn-on fluorescence emission in the presence of cyanide ion through ABIFE. On the other hand, the receptor L turns-off its fluorescence intensity upon binding with fluoride; however, the reduced emission intensity of this complex of L is recovered by addition of cyanide.

Supramolecular Assembly of Acriflavine on Graphene Oxide for the Sensing of Adenosine Phosphates.

An acriflavine-graphene oxide (GAF) supramolecular assembly has been prepared from water-soluble graphene oxide (GO) and a fluorescent dye, acriflavine (AF). Upon binding this non-covalently to the GO, the fluorescence of acriflavine has been "turned off" effectively, competitive binding potential of the sensor substrates such as ATP, ADP, AMP and the pyrophosphate weakens the supramolecular assembly of GAF, which allows the release of acriflavine quantitatively, which also "turns-on" the fluorescence of the dye under UV irradiation. Interestingly, GAF displayed the highest sensitivity towards ATP within the family of adenosine phosphates.

C symmetric tripodal molecular pocket for linear anions: Selective colorimetric detection of azide through N-Cu-π···hole interactions.

Tris(3-amino propyl)amine (TRPN) based Cv symmetric tripodal molecular pocket, L has been prepared and mono copper complex of L, (1) having Cu-N-π··· hole as recognizing elements, becoming a potential and selective colorimetric chemo sensor for perfect linear recognition of N, generate a Cu-NNN- π··· hole unit inside the tripodal pocket. Systematic spectrometric and naked-eye colorimetric studies reveal that, this chemo sensor is also colorimetrically recognizing the cyanide ion by its cavity via Cu-N-π···hole interactions; nevertheless, when azide anion is entering as a guest into the molecular pocket of 1 which is already hosted cyanide anion, then host displaces cyanide ion, subsequently azide is getting inside the cavity. The strength of the copper complex, 1 towards azide and cyanide are found to be 2.

Selective colorimetric sensing and perfect linear recognition of azide: Formation of Cu-azide-Cu cascade complex within the cavity of cryptand.

Bis-trpn [tris(3-aminopropyl)amine], capped dicopper complex of bicyclic cryptand L, 1, became a potential selective colorimetric chemosensor for azide anion. Complex 1 is generating a space inside the cylindrical cavity which will be opt for perfect linear recognition of azide anion through as N-Cu⋯N⋯Cu-N axle. Naked eye colorimetric and UV-Vis spectrometric investigations shows the complex 1 has the capability of selective sensing of azide anion.

A molecular phototropic system for cyanide: Detection and sunlight driven harvesting of cyanide with molecular sunflower.

We are reporting a simple, easy to prepare, and conformation switchable first molecular phototropic system L, "(E)-2-(2,4-dinitrophenyl)-1-((pyren-8-yl)methylene)hydrazine, for cyanide harvesting. This molecular phototropic system behaves as a molecular sunflower in which the conformation of this molecular sunflower can be altered in response to the sunlight. This molecular flower can sense and bind the cyanide anion colorimetrically through its transition state.

Most Efficient Tris(3-Aminopropyl) Amine Based Electron Deficient Tripodal Receptor for Azide.

Investigation on strength of the tris(2-amino ethyl) amine and tris (3-amino propyl) amine backboned tripodal receptors, L and L (incorporated with tripodal Cν frame, thio urea-amide linkage and π-hole assisting functionality) which are premeditated to explore the prospect for a particular anion recognition are studied. UV-Vis, H- NMR, and IR spectroscopy studies indicates that both the receptors sensing azide anion, colorimetrically and binds azide anion stronger than any other anions such as acetate, and cyanide. In particular the receptor L shows the highest binding strength towards azide anion.

Hydrogen bonding elements, π - hole functional moieties and Cv tripodal scaffold controlled turn-on cyanide and turn-off azide selective receptors.

Here in, we are reporting electron deficient amide and sulfonamide based tripodal receptors L, L, L and L. Systematic studies show a strong selectivity towards cyanide and azide anions. Detailed UV-Visible and fluorescent spectrometric investigation shows the amide based tripodal receptors L and L acts as a colorimetric and turn-on fluorescent chemo-sensor for cyanide, and the sulfonamide based tripodal receptors L and L acts as a colorimetric and turn-off fluorescent chemo-sensor for azide.

Traditional hydrogen bonding donors controlled colorimetric selective anion sensing in tripodal receptors: First-naked-eye detection of cyanide by a tripodal receptor via fluoride displacement assay.

Here in we report tris (3-aminopropyl) amine based tripodal receptors L, L and L which were functionalized with 4-nitrophenyl moieties having thio-urea, amide and sulfonamide as hydrogen bonding moieties respectively, shows a strong selectivity towards cyanide. A competitive colorimetric assay with L in the presence of fluoride ion suggests that the cyanide ion is much capable of displacing the bound fluoride, showing a sharp distinguishable color change. To the best of our knowledge, this is the first example of a naked-eye detection of cyanide via fluoride displacement assay by a tripodal receptor and such a displacement phenomenon is not observes in the cases of L and L, instead the receptor L binds nitrate and cyanide; L binds dihydrogen phosphate and cyanide.

Tuning the recognition properties of urea based receptor towards cyanide in aqueous medium: Effect of fluorine substitution on strength and selectivity of the anion receptor.

In this report, we have successfully tuned the selectivity and sensitivity of an anion receptor L by substituting electron withdrawing natured fluorine atoms directly on to the rim of the phenyl ring. Despite the fact that, we have two electron withdrawing natured nitro substituents on the other side of receptor L; two fluorine substitutions made dramatic change in the sensing ability as well as the selectivity of the receptor L towards anions. The acetonitrile solution contains L with tetrabutyl ammonium salts of fluoride, cyanide, acetate and dihydrogen phosphate results sudden color changes from yellow to brown; almost negligible spectral/color change for azide and bifluoride, where as there is no color change observed with any other anionic guests with L.

Simple and highly electron deficient Schiff-base host for anions: First turn-on colorimetric bifluoride sensor.

Here in, we have designed, synthesized and isolated sensor L, as a turn-on colorimetric chemo sensor for bifluoride ion. The acetonitrile solution contains L with tetrabutyl ammonium salts of bifluoride, cyanide and fluoride results sudden color changes from yellow to dark brown where as there is no color change observed with any other anionic guests with L. Solution state binding studies of L are carried out by UV-Vis spectrometry titration and the strengths of the chemosensor L towards bifluoride, cyanide and fluoride bindings are found to be 2.

Electron-deficient tripodal amide based receptor: An exclusive turn-on fluorescent and colorimetric chemo sensor for cyanide ion.

Here in, we have designed, synthesized and isolated sensor L, as an exclusive selective turn-on fluorescent chemo sensor for cyanide ion. The acetonitrile solution contains L with tetrabutyl ammonium cyanide, results sudden color change from colorless to yellowish-brown. Chemosensor L produced a strong fluorescence response with an enhancement of very high fluorescence intensity while addition of CN ion and the strength of the chemosensor L towards cyanide binding is found to be 3.

High Affinity Host-Guest FRET Pair for Single-Vesicle Content-Mixing Assay: Observation of Flickering Fusion Events.

Fluorescence-based single-vesicle fusion assays provide a powerful method for studying mechanisms underlying complex biological processes of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor)-mediated vesicle fusion and neurotransmitter release. A crucial element of these assays is the ability of the fluorescent probe(s) to reliably detect key intermediate events of fusion pore opening and content release/mixing. Here, we report a new, reliable, and efficient single-vesicle content-mixing assay using a high affinity, fluorophore tagged host-guest pair, cucurbit[7]uril-Cy3 and adamantane-Cy5 as a fluorescence resonance energy transfer (FRET) pair.

Reversible morphological transformation between polymer nanocapsules and thin films through dynamic covalent self-assembly.

A facile method has been developed for synthesizing polymer nanocapsules and thin films using multiple in-plane stitching of monomers by the formation of reversible disulfide linkages. Owing to the reversibility of the disulfide linkages, the nanostructured materials readily transform their structures in response to environmental changes at room temperature. For example, in reducing environments, the polymer nanocapsules release loaded cargo molecules.

3D tissue engineered supramolecular hydrogels for controlled chondrogenesis of human mesenchymal stem cells.

Despite a wide investigation of hydrogels as an artificial extracellular matrix, there are few scaffold systems for the facile spatiotemporal control of mesenchymal stem cells (MSCs). Here, we report 3D tissue engineered supramolecular hydrogels prepared with highly water-soluble monofunctionalized cucurbit[6]uril-hyaluronic acid (CB[6]-HA), diaminohexane conjugated HA (DAH-HA), and drug conjugated CB[6] (drug-CB[6]) for the controlled chondrogenesis of human mesenchymal stem cells (hMSCs). The mechanical property of supramolecular HA hydrogels was modulated by changing the cross-linking density for the spatial control of hMSCs.

Guest binding dynamics with cucurbit[7]uril in the presence of cations.

The binding dynamics of R-(+)-2-naphthyl-1-ethylammonium cation (NpH(+)) with cucurbit[7]uril (CB[7]) was investigated. Competitive binding with Na(+) or H(3)O(+) cations enabled the reaction to be slowed down sufficiently for the kinetics to be studied by fluorescence stopped-flow experiments. The binding of two Na(+) cations to CB[7], i.

A new photo-switchable "on-off" host-guest system.

A new photo-switchable "on-off" host-guest system comprising cucurbit[7]uril (CB[7]) and a photoresponsive cinnamamide derivative (trans-(3-phenyl-acryloylamino)-acetic acid, E-1) is studied. The cinnamamide derivative and CB[7] forms a stable 1 : 1 host-guest complex (CB[7]·E-1) with a high binding constant (K = 2.1 × 10(4) M(-1)).

Supramolecular fishing for plasma membrane proteins using an ultrastable synthetic host-guest binding pair.

Membrane proteomics, the large-scale global analysis of membrane proteins, is often constrained by the efficiency of separating and extracting membrane proteins. Recent approaches involve conjugating membrane proteins with the small molecule biotin and using the receptor streptavidin to extract the labelled proteins. Despite the many advantages of this method, several shortcomings remain, including potential contamination by endogenously biotinylated molecules and interference by streptavidin during analytical stages.