A detailed and comprehensive account of reported examples over the past two decades of anion coordinated neutral self-assemblies by neutral rigid and symmetrical dipodal receptors/sensors are ...demonstrated in the review.
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•Anion coordinated neutral self-assemblies of dipodal receptors/sensors.•Neutral receptors/sensors derived from rigid symmetric dipodal platforms.•Efficient/selective anion recognition/sensing in solid and solution phase.•Anion-coordinated molecular cages and clusters.•Optical chemosensors and transmembrane anion transport.
The last two decades have witnessed some modified approach in designing supramolecular anion receptors, not only for academic interests but also for their potential applications in biology and environment. Although, most of the tripodal based anion receptors are extensively studied in literature in a compact way, but the systematic and well-documented anion recognition study by dipodal receptors is still unexplored. The review aims to provide a detailed and comprehensive account of reported examples over last two decades of anion coordinated neutral self-assemblies of artificial dipodal receptors that employ several non-covalent interactions offered by specific low coordinating binding sites such as hydroxyl, amine, amide, thiamide, sulfonamide itself as well as from their hybrid functionalities such as amine-amide, amine-hydroxyl, amide-hydroxyl, hydroxyl-sulfonamide, amine-sulfonamide etc. This review specifically targets the rigid as well as symmetric dipodal backbone of anion receptors/sensors that discuss either the solid state structural aspects and/or the solution phase host–guest binding phenomena. Typical examples of anion-coordinated self-assembled supramolecular architectures including molecular barrel, capsules, foldamer, helicates, tetrahedral cages, mechanically interlocked systems as well as some colorimetric, chromogenic and fluorogenic chemosensors developed from covalently connected rigid dipodal low coordinating scaffolds are summarized other than high coordinating urea, thiourea scaffolds. Discussions relating to some potential applications in anion recognition, selective and sensitive anion sensing, cell imaging studies, transmembrane anion transport etc. as demonstrated by some of these dipodal receptors have also been included in this review.
The present study explores the direct and indirect impacts, mediated through perceived quality, of self-congruity and brand familiarity on purchase intention in a fashion retail branding context. ...Subsequently, the study examines the moderating role of gender in the relationships between self-congruity, perceived quality and brand familiarity and purchase intention. A structured questionnaire was used to collect data from fashion retail store shoppers aged 18 years and above. A mall-intercept survey technique was employed to collect data in Kolkata, a metropolitan city in India. Multivariate data analysis techniques, such as exploratory factor analysis, and structural equation modeling were used to analyze the data (n = 374). Results reveal that self-congruity, perceived quality and brand familiarity positively influence purchase intention. Results also indicate that the indirect impacts of self-congruity and brand familiarity on purchase intention are stronger than the direct ones. Finally, results show that gender moderates the relationships between self-congruity and purchase intention, perceived quality and purchase intention and brand familiarity and purchase intention. The academic and managerial implications of these findings are further discussed.
•Anion coordinated neutral/charged self-assemblies of positional isomeric receptors.•Acyclic positional isomeric receptor with different functionalities is discussed.•Anion-coordinated different ...types of molecular assemblies are summarized.•Aerial CO2 uptake, extraction, transport phenomena are also discussed.
Two or more supramolecular hydrogen-bonding receptor scaffolds having identical molecular formulas act as positional isomers only when the position of a substituent or a receptor arm or double/triple bond of one isomer differ from another isomer. The review summarizes the research on anion coordination chemistry of last decade affected by the positional isomeric acyclic receptors. The detailed and comprehensive account of reported examples of one or more anionic guest/hydrated-anionic guest assisted self-assemblies (neutral or charged) of artificial acyclic isomers (monopodal or linear, dipodal, triodal, hexapodal), affected by the terminal aryl substituents or the receptor arms with respect to central aryl spacer are systematically incorporated in the review. The review specifically consolidates the underexplored broad area of anion recognition chemistry affected by positional isomerism of acyclic amine, amide, urea, thiourea functionalized receptors/sensors in solid as well as in solution state. These substituent dependent isomeric systems could provide insights into the fundamental hydrogen-bonded anion-receptor chemistry and also useful for understanding the biological and environmental processes followed by the crystal engineering as well as extraction, aerial CO2 fixation, sensing or transport phenomena of anions. Discussions relating to the construction of some typical examples of anion-coordinated self-assembled supramolecular architectures such as molecular capsules, barrels, helicates, foldamer, tetrahedral cages and mechanically interlocked systems by these positional isomeric podands are also included in this review.
•Heavy metal bioremoval from mixture using sulfate reducing bacteria was evaluated.•Sulfate reduction to sulfide resulted in metal precipitation for removal.•More than 95% removal was obtained at low ...initial concentration combination of the metals.•Characterization of the bio-precipitates confirmed metal sulfides formation on the bacteria.
This study evaluated the combined effect of Cd(II), Cu(II), Ni(II), Fe(III), Pb(II) and Zn(II) on each other removal by anaerobic biomass under sulfate reducing condition. Statistically valid Plackett–Burman design of experiments was employed to carry out this mixture study. The results obtained showed a maximum removal of Cu(II) (98.9%), followed by Ni(II) (97%), Cd(II) (94.8%), Zn(II) (94.6%), Pb(II) (94.4%) and Fe(III) (93.9%). Analysis of variance (ANOVA) of the sulfate and chemical oxygen demand (COD) reduction revealed that the effect due to copper was highly significant (P value<0.05) on sulfate and COD removal. To establish the role of sulfate reducing bacteria (SRB) in the metal removal process, surface morphology and composition of the metal loaded biomass were analyzed by transmission electron microscopy (TEM) equipped with energy dispersive spectroscopy (EDS) and by field emission scanning electron microscopy (FESEM) integrated with energy dispersive X-ray spectroscopy (EDX). The results obtained revealed that the metal precipitates are associated with the outer and inner cell surface of the SRB as a result of the sulfide generated by SRB.
•Turn-ON fluorescence and colorimetric zinc sensor in a mixed buffered solution.•The sensor also responds to hazardous cadmium ion as fluorescent turn-ON sensor.•Pyrophosphate and dihydrogen ...phosphate sensing through metal complex ensembles.•The reversible and recyclable binding responds to a INHIBIT logic gate.
A benzothiazole functionalized chemosensor L1, exhibited colorimetric as well as fluorometric response to Zn2+ ion at physiological pH based on CHEF process. Selective naked eye detection of Zn2+ ion over most of the biologically important cations was also demonstrated. Sensing of biologically hazardous cadmium ion was also possible with L1. Further, both the zinc and cadmium ensembles of L1 were found to respond P4O74− and H2PO4− anion among other important biological anions and nucleotides via fluorescence quenching. Chemosensor L1, was also found to be reversible and recyclable toward Zn2+ and pyrophosphate ions over more than six cycles and responds to a INHIBIT logic gate. NMR titration and theoretical calculations were also conducted to understand the sensing behavior of L1.
We report the synthesis of a metal-free chemosensor for highly selective sensing of pyrophosphate (PPi) anion in physiological medium. The novel phenylbenzimidazole functionalized imine containing ...chemosensor (L; 2,6-bis(((4-(1H-benzodimidazol-2-yl)phenyl)imino) methyl)-4 methyl phenol) could sense PPi anion through “turn-on” colorimetric and fluorimetric responses in a very competitive environment. The overall sensing mechanism is based on the aggregation-induced emission (AIE) phenomenon. Moreover, a real time in-field device application was demonstrated by sensing PPi in paper strips coated with L. Interestingly, detection of intracellular PPi ions in model human cells could also be possible by fluorescence microscopic studies without any toxicity to these cells.
A new protocol for the catalytic synthesis of cyclopropanes using electron‐deficient alkenes is presented, which is catalysed by a series of affordable, easy to synthesise and highly active ...substituted cobalt(II) tetraaza14annulenes. These catalysts are compatible with the use of sodium tosylhydrazone salts as precursors to diazo compounds in one‐pot catalytic transformations to afford the desired cyclopropanes in almost quantitative yields. The reaction takes advantage of the metalloradical character of the Co complexes to activate the diazo compounds. The reaction is practical and fast, and proceeds from readily available starting materials. It does not require the slow addition of diazo reagents or tosylhydrazone salts or heating and tolerates many solvents, which include protic ones such as MeOH. The CoII complexes derived from the tetramethyltetraaza14annulene ligand are easier to prepare than cobalt(II) porphyrins and present a similar catalytic carbene radical reactivity but are more active. The reaction proceeds at 20 °C in a matter of minutes and even at −78 °C in a few hours. The catalytic system is robust and can operate with either the alkene or the diazo reagent as the limiting reagent, which inhibits the dimerisation of diazo compounds totally. The protocol has been applied to synthesise a variety of substituted cyclopropanes. High yields and selectivities were achieved for various substrates with an intrinsic preference for trans cyclopropanes.
Cobalt on call: We present a new protocol for the synthesis of cyclopropanes using electron‐deficient alkenes catalyzed by a series of affordable, easy to synthesize, and highly active substituted cobalt(II) tetraazaannulenes.
A simple Schiff's base fluorogenic probe for trivalent cation is designed. The receptor is biocompatible and used for live cell imaging.
•Newly synthesized colorimetric and flourogenic probe can ...selectively sense trivalent metal ions in mixed aqueous medium in ppm level.•Theoretical calculations justify the red shift and increase in emission intensity of L in the presence of M3+.•Interestingly, L alone and L in the presence of different trivalent cations were non-cytotoxic to model human cells (HeLa cells).•The switch ON emission behaviour of the ligand in the presence of M3+ is also demonstrated inside live HeLa cells.
A new imidazole functionalized anthracene based Schiff base (L) was synthesized and it's selective colorimetric as well as fluorescence responses to trivalent metal cations (Al3+, Fe3+ and Cr3+) over a variety of divalent and monovalent metal cations in 1:1 methanol–water mixed solvent and in live HeLa cells were demonstrated. These selective colorimetric and fluorescence responses were explained as a consequence of protonation of L, where the lower Ksp values of M3+ (Al3+, Fe3+ and Cr3+) facilitated the generation of H+ through hydrolysis. This fluorogenic behavior of the ligand L was further confirmed by theoretical calculations.
Purpose - The purpose of this paper is to investigate the moderating effects of selling experience on the relationship between job satisfaction and sales performance, customer orientation and sales ...performance, and adaptive selling behaviors and sales performance, taking the context of B2B insurance selling.Design methodology approach - Using a sample of 380 business-to-business insurance salespersons from an emerging market (India) to validate their model, the authors tested several hypotheses using structural equation modeling (SEM).Findings - The results suggest that experience works with customer-oriented selling in making the more experienced salespersons better performers. It was also found that for less experienced salespersons, the impact of job satisfaction on performance is weaker than for more experienced salespersons. In addition, it was found that more experienced salespersons' performance is better explained using job satisfaction and customer-oriented selling rather than their adaptive selling behaviors.Research limitations implications - The study contributes by explaining the mechanism for the above relationships. The study also contributes to knowledge by showing that more experience may not be always good for sales performance. Since the sample comes from an emerging market, the paper extends the knowledge from developed markets, and by testing in emerging markets.Practical implications - The managerial implications of this study lie in explaining those situations where experience can make salespersons more productive. The current sales literature on B2B selling contexts falls short of explaining this mechanism in salesperson performance.Originality value - This study contributes to knowledge uniquely by extending the body of empirical evidence that suggests that for experience, more is not always better. The study also shows that a more experienced salesperson does not improve his her performance by adopting adaptive selling strategies. Such adaptive selling strategies are probably more suitable for younger salespersons, given different expectations from them by customers. For experienced salespersons, job satisfaction and customer-oriented selling are more important than adaptive selling. This study explains the mechanism for the above relationships.
Optic Nerve Head Melanocytoma (ONHM) is a rare benign pigmented tumour of the uveal tract, seen commonly at the optic nerve head. The tumour is associated with a few ocular and systemic conditions. ...It usually remains stationary and rarely (1-2%) undergoes a malignant transformation. With the progressive understanding of its benign nature with advancing imaging modalities, observation with regular follow-up is the mainstay of treatment. A 35-year-old female, presented with complaints of foreign body sensation in both eyes. She was a known case of graves’ disease under treatment with anti-thyroid drugs and beta blockers. Ocular examination revealed classic signs of thyroid eye disease. The left eye fundus revealed a large, black, globular tumour in the optic nerve head obscuring the entire disc and Ultrasound B scan revealed a tumour at the optic nerve head with high echogenicity. Optical Coherence Tomography (OCT) through the mass revealed a dome-shaped elevation with obscuration of underlying details due to heavy pigmentation, with no signs of subretinal exudation or edema. Thyroid profile was within normal limits. A diagnosis of left eye ONHM was made. The patient was started on tapering doses of systemic steroids and was regularly followed up to monitor the tumour growth for 18 months. This is the first reported case of ONHM co-existing with thyroid eye disease and this association could be coincidental or embryological. This case highlights the need for ophthalmologists to be familiar with this benign condition and for regular careful follow-up of such patients.
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