Phenyl Amino Research Articles

Tracking metal ions with polypyrrole thin films adhesively bonded to diazonium-modified flexible ITO electrodes.

Adhesively bonded polypyrrole thin films doped with benzene sulfonic acid (BSA) were electrodeposited on aminobenzenediazonium-modified flexible ITO electrodes and further employed for the detection of Pb2+, Cu2+, and Cd2+ metal ions in aqueous medium. The aminophenyl (AP) adhesive layer was grafted to ITO by electroreduction of the in situ generated parent diazonium compound. Polypyrrole (PPy) thin films exhibited remarkable adhesion to aminophenyl (ITO-AP). The strongly adherent polypyrrole films exhibited excellent electroactivity in the doped state with BSA which itself served to chelate the metal ions in aqueous medium. The surface of the resulting, modified flexible electrode was characterized by XPS, SEM, and electrochemical methods. The ITO-AP-PPy electrodes were then used for the simultaneous detection of Cu2+, Cd2+, and Pb2+ by differential pulse voltammetry (DPV). The detection limits were 11.1, 8.95, and 0.99nM for Cu2+, Cd2+, and Pb2+, respectively. In addition, the modified electrodes displayed a good reproducibility, making them suitable for the determination of heavy metals in real wastewater samples.

LC and LC–MS/MS studies for the identification and characterization of degradation products of acebutolol

The aim of the present investigation was to demonstrate an approach involving use of liquid chromatography (LC) and liquid chromatography-mass spectrometry (LC–MS) to separate, identify and characterize very small quantities of degradation products (DPs) of acebutolol without their isolation from the reaction mixtures. The drug was subjected to oxidative, hydrolytic, thermal and photolytic stress conditions as per International Conference on Harmonization (ICH) guideline Q1A(R2). Among all the stress conditions the drug was found to be labile in hydrolytic (acidic & basic) and photolytic stress conditions, while it was stable in water-induced hydrolysis, oxidative and thermal stress conditions. A total of four degradation products were formed. A C18 column was employed for the separation of all the DPs on a gradient mode by using high-performance liquid chromatography (HPLC). All the DPs were characterized with the help of their fragmentation pattern and the masses obtained upon LC–MS/MS and MSn analysis. All the hitherto unknown degradation products were identified as 1-(2-(2-hydroxy-3-(isopropylamino)propoxy)-5-(amino)phenyl)ethanone (DP-I), N-(4-(2-hydroxy-3-(isopropylamino)propoxy)-3-acetylphenyl)acrylamide (DP-II), 1-(2-(2-hydroxy-3-(isopropylamino)propoxy)-5-(hydroxymethylamino)phenyl)ethanone (DP-III) and 1-(6-(2-hydroxy-3-(isopropylamino)propoxy)-2,3-dihydro-2-propylbenzo[d]oxazol-5-yl)ethanone (DP-IV). Finally the in-silico carcinogenicity and hepatotoxicity predictions of the drug and all the DPs were performed by using toxicity prediction softwares viz., TOPKAT, LAZAR and Discovery Studio ADMET. The results of in-silico toxicity studies revealed that acebutolol (0.967) and DP-I (0.986) were found to be carcinogenic, while acebutolol (0.490) and DP-IV (0.437) were found to be hepatotoxic.

Efficient co-host exciplex emission for white organic light-emitting diodes

In this study, white organic light-emitting diodes (WOLEDs) based on exciplexes with a simple structure were investigated. Several combinations of hole-transport material and electron-transport material (ETM) were examined to verify the formation of the exciplexes. Various combinations of these exciplexes contributed to the blue and green emitters, as well as the host within the WOLEDs. Four types of WOLEDs were fabricated using various ETMs 2,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi), 4,7-diphenyl-1,10-phenanthroline (BPhen), bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum (BAlq), and 2,6-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (26DCzppy) within the emitting layers (EMLs). In this work, which comprised a blue EML with a 1:1 wt ratio of tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and TPBi, a green EML prepared by mixing 4,4′,4″-tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA) and ETMs at a weight ratio of 1:1, and a red EML. In addition, the exciplex formation was optimized according to the mixing concentration of the green EML when BPhen and TPBi were used as the ETM. As a result, a green EML was obtained at 50 wt% TPBi with improved performance, such as an increased power efficiency and a low efficiency roll-off in the range of 200–1000 cd/m2 in WOLEDs. It also showed white emission for Commission Internationale de l’Éclairage coordinates of (0.45, 0.45) at 1000 cd/m2.

Nutritional and Functional Properties of Two Dried Brown Seaweeds Sirophysalis trinodis and Polycladia myrica

ABSTRACTSirophysalis trinodis and Polycladia myrica, two brown seaweeds present on the southeast coast of Iran, were evaluated for their nutritional and functional properties after drying. Fourier transform-infrared spectroscopy (FTIR) analysis of crude polysaccharides revealed the characteristic absorption bands of phenol, O–H, C–H, C–O–S, C–O, C=O, C–H groups, and β-glycosidic linkages from cellulose, with the sulfate contents estimated as 4.89 ± 0.11% and 6.96 ± 0.05% of SO4−2. Results of nutritional profiles revealed all of the essential amino acids, especially methionine, isoleucine, leucine, lysine, threonine, valine, phenyl alanine, and arginine. In addition, important fatty acids such as linolenic acid, palmitic acid, and oleic acid were found in high amounts. The other nutritional components present in high amounts were proline and minerals such as calcium, magnesium, iron, manganese, copper, and zinc. The antibacterial activity was weak, but the result of antioxidant activities (hydroxyl and superoxide radicals scavenging and ferrous-ion chelating ability) of crude polysaccharides was considerable. In general, the findings of this study recommend that S. trinodis and P. myrica dried seaweeds have a potent nutritional value and might be used as a valuable source of nutrient supplements for humans and animals.

Variability of the Transformations of 4-Hydroxy-6-methyl-2H-pyran-2-one under Modified Biginelli Reaction Conditions

A modified version of the three-component Biginelli reaction of 4-hydroxy-6-methyl-2H-pyran-2-one with aromatic aldehydes in urea under conventional heating and microwave activation has been studied. Depending on the order of addition of the reactants, substituted (pyrano)chromenones, 10-amino-4a-hydroxydihydropyranochromen- 2-one, and 3-[amino(phenyl)methyl]-4-hydroxypyran-2-one were obtained.

SYNTHESIS OF NOVEL QUINAZOLIN-4(3H)-ONYL AZETIDINONES AS POTENTIAL ANTICONVULSANT AGENTS

A series of 4-(substituted aryl)- 1- [2’- methyl-6’- substituted anilino quinazolinon-4’-(3’H)-onyl ] -3- chloroazetidin- 2-ones 14-25 have been synthesized by addition of substituted anilines to 4-(substituted aryl)- 1- [2’- methyl-6’- bromoquinazolinon-4’-(3’H)-onyl ] -3- chloro- azetidin-2-ones 8-13 which in turn were prepared by the cycloaddition of triethylamine in dioxane to 3-(N-substituted benzylidene amino phenyl amido )-2-methyl-6-bromoquinazolin-4(3H)-ones 2-7 in presence of acetyl chloride. These compounds were screened for anticonvulsant activity and acute toxicity. Compound 4-(substituted aryl)- 1- [2’- methyl-6’- substituted anilino quinazolinon-4’-(3’H) – onyl ] -3- chloro-azetidinone showed most potent activity. The structure of all the synthesized compounds were delineated by elemental (C, H, N ) and spectra (IR, proton magnetic resonance and mass ) analysis.

Innovative Synthesis and Anti-Microbial Activity Study of Innovative Mannich Bases Containing 2- Phenoxy-1, 3, 2-Dioxa Phospholanes and Indole Systems

In the present study, synthesis, characterization, antimicrobial activity on some novel pyrazolone derivatives has been taken up. The primary amines were diazotized with sodium nitrite and HCl mixture at 0-5 0 C which were further coupled with ethyl acetoacetic ester to afford phenyl diazonium acetoacetic esters (II). Condensation of 4-substituted aryl hydrazono acetoacetic ester, 4-hydrazinylbenzenamine in the presence of catalytic amount of DMF under microwave irradiation afforded (4Z)-4-(2-substituted aryl hydrazono)-1-(4-aminophenyl)-3-methyl-1H-pyrazol-5(4H)-one (III). Subjecting (III) to anhydrous K 2 CO 3 in DMF for 8 hours afforded 2-{4-[(4Z)-4-(2-substituted aryl hydrazono)-4, 5-dihydro-3-methyl-5-oxopyrazol-1-yl] phenyl amino} acetate( IV) which was further reacted with hydrazine hydrate to afford 2-{4-[(4Z)-4-(2-substituted aryl hydrazono)-4, 5-dihydro3-methyl-5-oxopyrazol-1-yl] phenylamino} acetohydrazide (V). Reaction of (V) and Isatin (VI b) in DMF afforded (4Z)-2-(4-((15Z)-4-(2-phenylhydrazono)-4,5-dihydro-3-methyl-5 oxopyrazol-1-yl) phenylamino)-N’-(2-oxoindolin-3-ylidene)acetohydrazide (VII). Compound (VII) was subsequently subjected to Mannich reaction with cyclic secondary amines (piperidine/morpholine/N-methyl piperidine) in the presence of formaldehyde in DMF to afford (4Z)-2-(4-((15Z)-4-(2-substituted aryl hydrazono)-4,5-dihydro-3-methyl-5-oxopyrazol-1-yl)phenylamino)-N’-(2-oxo-1-((piperidin-1-yl)methyl) indolin-3-ylidene)acetohydrazide (VIII) which was characterized by I.R, 1HNMR and Mass data. The anti-bacterial activity of synthesized compounds was studied by the disc diffusion method against pathogenic bacteria and fungi.

Cold atmospheric plasma treatment affects early bacterial adhesion and decontamination of soft reline palatal obturators

PurposeThe aim of this work is to evaluate the possibility of using CAPs for the treatment of sterile soft reline palatal obturators before their application on patients to prevent or reduce biofilm formation and, subsequently, the implant failure, and for their decontamination once they are removed from the patient's palate, in order to make them suitable for the subsequent re-application. MethodsPlasma is generated using two dielectric barrier discharge and tested against the oral biofilm formers Streptococcus mutans and Aggregatibacter actinomycetemcomitans. Relines are either plasma treated before being infected with 24 h biofilm, or infected with 90 min (early) or 24 h (mature) biofilm prior to be plasma treated for 30, 60, or 120 s. Bacteria numbers and viability are evaluated by Colonies Forming Units counts (CFU) and quantitative colorimetric metabolic 2,3-bis (2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenyl amino) carbonyl]-2H-tetrazolium hydroxide assay (XTT). Cytocompatibility is assayed towards human primary fibroblasts and keratinocytes cultivated on plasma-treated specimens by colorimetric metabolic 3-(4,5-Dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay and light microscopy. ResultsPlasma treatment of sterile reline affects bacterial adhesion, reducing CFU number and viability by 2 logs and by 50%, in comparison with untreated controls (p < 0.05). Plasma efficacy is marked against early biofilm: after 120 s, CFUs are reduced by 3 logs, and viability decreased by about 60% (p < 0.05). Significant results are also observed for mature biofilm: CFUs and viability are reduced by approximately 2 logs and 40% (p < 0.05), after 120 s exposure. Lastly, MTT does not show any toxic effect on human cells. ConclusionsCold atmospheric plasma could represent a very promising skill for soft reline shutters decontamination.

Characterization of optical and morphological properties of chalcone thin films for optoelectronics applications

Thin films of a chalcone 1-(4-chlorophenyl)-3-(4- N, N dimethyl amino phenyl)-2-propen-1-one (CDP) were prepared. The chalcone was dissolved in acetone with different concentrations to achieve thin films of different thicknesses. The solution was deposited by spin coating technique on glass substrates. The optical spectra of the chalcone thin films (CDP-TFs) were recorded. FTIR, DRS, NMR, TGA and DSC were used to characterize and investigate the chalcone properties as power and thin films. XRD and SEM have demonstrated the structure and surface morphology of the (CDP-TFs) depends strongly on film thickness. The findings revealed that the variations of the thickness from 150 to 400nm have led increasing the crystal size from 2.92 to 78.51nm. In contrast, the macrostrain was shifted to lower values. Furthermore, the energy band gaps of CDP-TFs increased by increasing the film thickness. To the best of our knowledge, this is a first report on the structural and optical properties chalcone as thin films.

Synthesis, characterization and photo physical-theoretical analysis of D-π-A compounds. 2. Chain length effect through even-odd effect on the photophysical properties

In the continuous search for new compounds for solar devices, the family of dipolar D-π-A molecules, which have a donor (D) and an acceptor (A) charge joined by a conjugate bridge, have been the focus of attention in the recent years due their different properties. As we have shown before, there is a connection between the geometry of molecules based on tertiary asymmetric amines and their quantum yield. In the current work, four new compounds based on the same backbone molecule ((E)-2-cyano-3-(5-((E)-2-(9,9-diethyl-7-(phenylamino)-9H-fluoren-2-yl)vinyl)thiophen-2-yl)acrylic acid), but with different substituent, were synthesized. It is shown that the chain-size of the substituent group modifies the quantum yield. The news substituents introduced are a propyl (M8-3), butyl (M8-4), pentyl (M8-5) or hexyl (M8-6) group. In general, it was possible to see that the new substituents were able to increase their performances. Furthermore, an odd-even substituent effect, between propyl/pentyl and butyl/hexyl, was found and the theoretical geometrical data was able to follow the trend. However, theoretically, this substituent effect was inverted in the case of M8-3 and M8-4, which may be due to the disappearance in the emission patterns of an excited state close to 450 nm (at λ2), as it was shown in the experimental data. The most suitable behaviour belongs to [(E)-2-cyano-3-(5-((E)-2-(9,9-diethyl-7-(phenyl(propyl)amino)-9H-fluoren-2-yl)vinyl)thiophen-2-yl)acrylic acid] (M8-3). M8-3 has the highest quantum yields on average in all studied solvents; even higher than the last reported compounds with methyl (M8-1) and ethyl (M8-2) groups. Theoretically, the most likely explanation is that the dihedral angle formed between the carbonyl acceptor and nitrogen electron donor (Aryl-CO), should be as small as the molecule M8-3. This isolated compound has an average quantum yield including all solvents of 58.1% (average value), showing that a long group is not necessary to improve the performance.

Influence of anchoring of a pyrazoline dye 3-naphthyl-1-phenyl-5 (4-amino phenyl)-2-pyrazoline (NPAP) in manipulating the electronic and chemical properties of a graphene oxide via amidation: Synthesis, characterization and photophysics

Owing to the unique opto-electronic properties, pyrazoline derivatives are considered to be one of the most elegant member in heterocyclic family. In this work we have utilized a pyrazoline dye 3-naphthyl-1-phenyl-5-(4-amino phenyl)-2-pyrazoline (NPAP) for functionalizing graphene oxide (GO) through amide linkage, as the progress of graphene based materials are quicker than other comparable materials. All the employed characterization techniques support the bridging of –NH bond between the two segments. Moreover, the enhanced photophysical properties of the resulting hybrid (GO-NPAP) reflect an efficient charge delocalization, allowing an electronic interaction at the interface of GO and NPAP partners as they are electronically separated. Very simple, economic and an effective reagent for making GO fluorescent, it is expected that the pyrazoline functionalized GO will hold a prominent position in developing high-performance graphene based devices.

Removal behaviors of sulfamonomethoxine and its degradation intermediates in fresh aquaculture wastewater using zeolite/TiO2 composites

Removal efficiencies of sulfamonomethoxine (SMM) and its degradation intermediates formed by treatment with zeolite/TiO2 composites through adsorption and photocatalysis were investigated in fresh aquaculture wastewater (FAWW). Coexistent substances in the FAWW showed no inhibitory effects against SMM adsorption. Although coexistent substances in the FAWW inhibited the photocatalytic decomposition of SMM, the composites mitigated the inhibition, possibly because of concentration of SMM on their surface by adsorption. LC/MS/MS analyses revealed that hydroxylation of amino phenyl and pyrimidinyl portions, transformation of the amino group in the amino phenyl portion into a nitroso group, and substitution of the methoxy group with a hydroxyl group occurring in the initial reaction resulted in the formation of various intermediates during the photocatalysis of SMM. All detected intermediates had a ring structure, and almost all intermediates disappeared at the same time SMM was completely decomposed. Ph–OH formed by hydroxylation of the phenyl portion was detected upon decomposition of SMM during photocatalysis. The removal of Ph–OH by the composites proceeded more rapidly than that by TiO2 alone under ultraviolet irradiation. The SMM and Ph–OH were completely degraded by the composites within 30min, showing that the zeolite/TiO2 composites were effective in removing SMM and its intermediates from FAWW.

Design and synthesis of ferrocene-terminated hyperbranched polyimide for memory devices

In this work, a novel tetra-amine, bis (4-(3, 5-bis (4-amino-2-(trifluoromethyl) phenoxy) phenoxy) phenyl) methanone, was synthesized and then utilized to produce hyperbranched polyamic acids via polycondensation with 4, 4’-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). The resulting hyperbranched polyamic acids underwent termination by (4-amino) phenyl ferrocene and imidization, leading to ferrocene-terminated hyperbranched polyimide (HBPI-Fc). The resulting HBPI-Fc displayed superior solubility in conventional organic solvents and excellent thermal stability. A memory device with a configuration of indium tin oxide (ITO)/HBPI-Fc/Al was fabricated, in which the HBPI-Fc acted as the active layer. The device exhibited bistable electrical conductivity switching and nonvolatile bipolar write-once-read-many-times memory character with two threshold voltages of 2.2 V and −2.6 V, respectively, during positive and negative voltage sweep. The device exhibited an ON/OFF current ratio of 104 under a constant bias of −1.0 V and good stability in both ON- and OFF-state during the test period of 104 s. The revealed electrical bistability of the HBPI-Fc was found mainly due to the effective charge trapping effect of the electroactive terminal ferrocene groups.

Dichloro-substituted phenyl amino propanamides exhibit anticonvulsant effect and reduce inward sodium ion current (NaV1.6)

This research studied the anticonvulsant properties of three synthesized isomers of dichloro-substituted phenyl amino propanamides in rodents and determined their effects on votage-gated sodium channels (NaV1.6) stably expressed in Human Embryonic Kidney (HEK Cells 293). 2,3-, 2,5- and 3,4- Dichloro anilines were reacted with acrylamide according to Michael-type addition reaction to obtain their corresponding isomers; DCP23, DCP25 and DCP34. Each isomer was evaluated for anticonvulsant effects using maximal electroshock (MES)- and pentylenetetrazole (PTZ)- induced seizure models in mice; tested against PTZ-induced kindling in rats and its synergistic effect with fluphenamic acid in mice. Effects of DCP23 and DCP25 were studied on voltage-gated sodium channels (NaV1.6) at different states of the channel, using electrophysiology techniques. The test compounds generally offered dose dependent protection against maximal electroshock- and pentylenetetrazole (PTZ)- induced seizure; demonstrated synergistic effect when co-administered with fluphenamic acid; and produced significant (p<0.05) decrease in seizure progression in PTZ-kindled rats. DCP23 and DCP25 reduced sodium currents at different channel states in a concentration dependant manner. The results of this study showed that the compounds possess anticonvulsant effects and reduced the inward sodium currents. Therefore, they could exert anticonvulsant activity via sodium channels blockade.

Tris(N-{bis-[meth-yl(phen-yl)amino]-phosphor-yl}benzene-sulfonamidato-κ2O,O')(1,10-phenanthroline-κ2N,N')lanthanum(III).

The asymmetric unit of [La(C20H21N3O3PS)3(C12H8N2)] is created by one LaIII ion, three deprotonated N-{bis-[meth-yl(phen-yl)amino]-phosphor-yl}benzene-sulfonamidate (L-) ligands and one 1,10-phenanthroline (Phen) mol-ecule. Each LaIII ion is eight-coordinated (6O+2N) by three phosphoryl O atoms, three sulfonyl O atoms of three L- ligands and two N atoms of the chelating Phen ligand, leading to the formation of six- and five-membered metallacycles, respectively. The lanthanum coordination polyhedron has a bicapped trigonal-prismatic geometry. 'Sandwich-like' intra-molecular π-π stacking inter-actions are observed between the 1,10-phenanthroline ligand and two benzene rings of two different L- ligands. The phenyl rings of L- that are not involved in the stacking inter-actions show minor positional disorder. Mol-ecules form layers parallel to the (010) plane due to weak C-H⋯O inter-molecular hydrogen bonds. Unidentified highly disordered solvate mol-ecules that occupy ca 400 Å3 large voids have been omitted from the refinement model.

Dansylated adenine as a molecular probe for exploring hydrophobic pocket of bovine serum albumin (BSA) and its utility for mercury ion recognition

Bovine serum albumin (BSA) is a well characterized protein with a distinct hydrophobic region in its molecular architecture. Literature survey indicates that the tertiary structure of BSA comprises of homologous domains with subdomains (I, II and III). It has been postulated that hydrophobic pocket of subdomain II is dynamic in nature and it carves out two sites I and II that encompass amino acids tryptophan, tyrosine and phenyl alanine in specific positions. BSA usually binds to different ionic and molecular species at site I (with a cavity size of 2.53Å) or site II (cavity size 2.6) depending upon appropriate combination of hydrophobic, hydrogen bonding and electrostatic interactions [7]. In order to study the dynamic nature of hydrophobic pocket of BSA and its role in ionic and molecular recognition, we have synthesized a new dansylated adenine (DA) that exhibits solvatochromism and fluorescence enhancement on interaction with BSA in aqueous media. Detailed fluorescence and absorption spectral studies reveal that it is possible to lock one of the sites (site I) by synthesized dansylated adenine while the remaining site can be used for selective interaction with small organic molecules or metal ions. The specificity of this interaction at site II to mercury has been examined to understand possible locking of active sites of proteins for metal ion recognition to pave way for innovative molecular technologies.

Effect of Al:Ag alloy cathode on the performance of transparent organic light-emitting devices

Transparent organic light-emitting devices (TOLEDs) based on a stacked alloy cathode of LiF/Al:Ag are investigated. The devices have a structure of indium-tin-oxide (ITO)/4,4′,4″-Tris[2-naphthyl(phenyl)amino]triphenylamine (2T-NATA) (25 nm)/N,N′-Di-[(1-naphthyl)-N,N′-diphenyl]-1,1’-biphenyl-4,4′-diamine (NPB) (40 nm)/tris-(8-hydroxyquinoline) aluminum (Alq3) (50 nm)/LiF (1 nm)/Al:Ag (1:3) (x), where the thicknesses of cathode metal layers (Al:Ag) are adjusted, respectively, from 70 nm to 100 nm. In the experiment, it is found that the LiF (1 nm)/Al:Ag (1:3) (75 nm) has good electron injection efficiency. Compared with an Al-only cathode, the turn-on voltage is lowered. At the voltage of 10 V, the luminances for bottom emission from ITO anode side and top emission from metal cathode side are 2 459 cd/m2 and 1 729 cd/m2, respectively. Thanks to electron injection enhancement by using Al:Ag cathode, we can obtain a better energy level matching between the cathode and the organic layer, thus the devices have lower turn-on voltage and higher luminance. The total transmittance of the devices can achieve about 40% at the wavelength of 550 nm.

Effects of Metal Phthalocyanines as Hole-transporting Layers of Perovskite-based Solar Cells

Halogen halide perovskite solar cells using active layer of CH3NH3PbI3 with vanadyl phthalocyanine (VOPc), vanadyl naphthalocyanine (VONc) and, tetrakis (tert-butyl)[bis(trihexylsiloxy)germanium phthalocyanine] (GePc) doped 2,2',7,7'-tetrakis-(N,N-di-4-methoxy phenyl amino)-9,9'-spirobifluorene (Spiro-OMeTAD) as hole- transporting layers were fabricated and characterized for optimizing with tuning the photovoltaic performance, optical properties, and microstructure. Introducing of metal phthalocyanine into the hole-transporting layer improved the photovoltaic properties including carrier diffusion with increase of carrier mobility, optical absorption, and the perovskite crystal growth. The metal phthalocyanines had the effect of promoting optically induced carrier generation and improvement of the charge transport with suppression of carrier recombination as electron blocking layers on the photovoltaic mechanism. The energy diagram and photovoltaic mechanism are discussed by the experimental results.

Lactose tailored boronic acid conjugated fluorescent gold nanoclusters for turn-on sensing of dopamine

Dopamine being a neurotransmitter and chemical messenger plays a vivacious role in a number of significant medical conditions like Parkinson’s disease, Attention Deficit Hyperactivity Disorder, Schizophrenia, and drug addiction. As turn-on sensors have a superior level of selectivity than fluorescence quenching based sensors, we developed a fluorescence retrieval strategy for dopamine sensing. Here, highly fluorescent amino phenyl boronic acid (APBA)‒conjugated gold nanocluster (Au‒BSA‒APBA probe) has been synthesised from bovine serum albumin‒protected gold nanocluster (Au‒BSA NCs). Boronic acid forms boronate ester with disaccharides such as lactose due to its affinity to polyols. Hence fluorescence of Au‒BSA‒APBA probe is quenched when it binds with lactose molecules through boronate ester formation. The fluorescence of Au‒BSA‒APBA‒lactose system can be retrieved (turn-on) with dopamine by the competitive displacement of lactose from the probe surface which suggests the higher affinity of boronic acid to the catechol group of dopamine. Furthermore, real samples spiked with dopamine including human serum and urine were analysed using this turn-on sensor and showed excellent recovery percentage. The developed fluorescent sensor offered high selectivity for dopamine over other catecholamines and aminoacids with detection limit as low as 0.7 μM.

Selective interaction of N,N-bis(aminobenzyl)naphthalenediimides with fluoride anion

In this work, the optical properties of N,N-bis(aminobenzyl)naphthalenediimides 2a–2d (BzNDIs) and their interaction with fluoride were studied. The results demonstrated that the amino group position in the benzyl substituent exerts an effect in the absorption and emission properties. Particularly, the N,N-bis(2-aminobenzyl)NDI 2b presented non-typical absorption and emission bands which indicate an intramolecular charge transfer from the amino phenyl group to the NDI core. As the concentration of 2b increases, the solution turns from colourless to a pale orange colour. The interaction of BzNDIs 2a–2d with anions was selective towards fluoride and the affinity was in the order para > ortho > meta with respect to the position of the amino group in the aminophenyl ring. Interestingly, the colour change in the solution of 2b upon addition of fluoride makes it a good candidate for a fluoride colorimetric detection. The voltammetry analysis indicates the ability of these molecules to accept two electrons, in consequence the interaction of two fluoride anions with the BzNDIs was observed.