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Showing papers by "Edamana Prasad published in 2019"


Journal ArticleDOI
TL;DR: The present study paves the way, for the first time, towards AIE driven dual stimuli response in indeno-pyrrole based D-A fluorophores as a dual sensor for volatile acids and aromatic amines.
Abstract: In the present work, a novel donor (D)–acceptor (A) fluorophore based on indeno-pyrrole derivative (PYROMe) has been utilized as a dual sensor for volatile acids and aromatic amines, where sensory ...

39 citations


Journal ArticleDOI
TL;DR: PYDMSA is a unique sensor which can be used to detect and detoxify mercury at the same time in living samples and exhibits high selectivity for Hg2+ over other competing metal ions with an experimental detection limit.
Abstract: Strategies for simultaneous detection and detoxification of Hg^(2+) using a single sensor from biological and environmental samples are limited and have not been realized in living organisms so far. We report a highly selective, small molecule “turn-on” fluorescent sensor, PYDMSA, based on the cationic dye Pyronin Y (PY) and chelating agent meso-2,3-dimercaptosuccinic acid (DMSA) for the simultaneous detection and detoxification of inorganic mercury (Hg^(2+)). After Hg^(2+) detection, concomitant detoxification was carried out with sufficient efficacy in living samples, which makes the sensor unique. PYDMSA exhibits high selectivity for Hg^(2+) over other competing metal ions with an experimental detection limit of ∼300 pM in aqueous buffer solution. When PYDMSA reacts with Hg2+, the CS–C^9 bond in the sensor gets cleaved. This results in the “turn-on” response of the fluorescence probe with a concomitant release of one equivalent of water-soluble Hg^(2+)–DMSA complex which leads to a synchronous detoxifying effect. The sensor by itself is nontoxic to cells in culture and has been used to monitor the real-time uptake of Hg^(2+) in live cells and zebrafish larvae. Thus, PYDMSA is a unique sensor which can be used to detect and detoxify mercury at the same time in living samples.

38 citations


Journal ArticleDOI
TL;DR: In this paper, a unique chemodosimetric design approach for selective sensing of CN− ion, in both solution and solid states, was presented, where the fluorophore is threaded by a fluorene derivative and the bulky fluorine unit regulates the interaction between the fluoropore units to minimize aggregation caused quenching (ACQ).
Abstract: Designing fluorescent molecular probes with longer wavelength emission (above 600 nm) features towards exclusive detection of CN− ion is highly challenging and rarely found in the field of fluorescent sensors. The contribution here reports a unique chemodosimetric design approach for selective sensing of CN− ion, in both solution and solid states. Towards this, we have utilized an orange emitting fluorescent probe (R1) (λ emission > 600 nm), where the fluorophore is threaded by a fluorene derivative. The bulky fluorine unit regulate the interaction between the fluoropore units to minimize aggregation caused quenching (ACQ). Upon introducing CN− ion, even in the presence of several other ions, intramolecular charge transfer (ICT) from the donor (phenothiazine) to the acceptor (cyanovinyl unit) was completely blocked in the covalently threaded fluorescent moiety and as a result the fluorescence was completely quenched. More importantly, the present system retained its fluorescence properties in the solid state and hence was utilized to detect CN− ion in the solid state through fluorescence quenching mechanism, which enabled the fabrication of a test kit for on-site analysis of CN− ion. DFT and TD-DFT calculations towards validating the experimental results were also performed in order to study the changes caused in the electronic properties of R1 before and after complexation with CN− ion.

34 citations


Journal ArticleDOI
24 May 2019
TL;DR: The increased threat of bacterial resistance against conventional antibiotics has warranted the need for development of membrane targeting antibacterial agents, and several self-assembled cationic amphitopes are being developed.
Abstract: The increased threat of bacterial resistance against conventional antibiotics has warranted the need for development of membrane targeting antibacterial agents. Several self-assembled cationic amph...

30 citations


Journal ArticleDOI
TL;DR: The unique design strategy of the gel and the characteristic physicochemical properties of the lanthanide ions resulted in the unprecedented ability of the system to monitor changes in environmental stimuli over a considerable range.
Abstract: Fine tuning the optical properties of lanthanide-based gels using low molecular weight gelators has several advantages over the polymeric gelator analogues. Herein, we have prepared a lanthanide-based gel using low molecular weight citric acid as the assembler ligand and the optical properties of the gel were fine-tuned, utilizing a mixed ligand approach, enabling white light emission and environmental sensing (pH and temperature). The coligand utilized in the study was 4'-(4-bromophenyl)-2,2':6',2''-terpyridine. The resultant mixed-ligand gel exhibited green and red emissions in the presence of Tb(iii) ions and Eu(iii) ions, respectively. White light emission was achieved, with CIE coordinates (0.33, 0.32), in the bimetallic Tb/Eu metallogel formed by the precise control over Tb/Eu ratio. The correlated color temperature (CCT) for white-light-emitting gel was calculated, and the value of 5473 K suggests that the system generates cool white light. While most of the reported low molecular weight gelators exhibit on-off responses to stimulus at a particular value, the present system is capable of gradually monitoring changes for stimuli such as pH and temperature over a wide range (pH from 4-11 and temperature from 20 to 70 °C). The unique design strategy of the gel and the characteristic physicochemical properties of the lanthanide ions resulted in the unprecedented ability of the system to monitor changes in environmental stimuli over a considerable range.

27 citations


Journal ArticleDOI
TL;DR: In this paper, an attempt is made to use FTIR spectroscopy to identify the thermal transitions in unmodified and three modified bitumen and the changes in peak position and intensity of the C-H stretching vibration at 2953, 2923 and 2853 cm−1 were analyzed.
Abstract: The transitions in bitumen in the temperature range of 25–75 °C are normally investigated using rheological tools. Considering the complex response of the material in such temperature range, it will be helpful if the precise nature of the material is investigated at the macromolecular level also. In this study, an attempt is made to use FTIR spectroscopy to identify the thermal transitions in unmodified and three modified bitumen. The changes in peak position and intensity of the C–H stretching vibration at 2953, 2923 and 2853 cm−1 were analyzed. Transitions, predominantly solid–solid in nature were identified in the temperature range of 35–65 °C which can be attributed to the change in conformation of the crystalline fraction. While certain peaks distinguished the effect of modification and aging, few other peaks indicated multiple transitions in the solid state of the material. The degree of crystallinity, also calculated from the FTIR spectra, indicated changes in the conformation of the material in the temperature range of 45–55 °C.

26 citations


Journal ArticleDOI
TL;DR: The obtained results from steady-state and time-resolved optical studies, along with X-ray diffraction and computational studies demonstrate aggregation-induced emission enhancement (AIEE) of a donor-π-acceptor based 1,3-diarylpropynone, namely 1-phenyl-3-(pyren-1-yl)prop-2-yn- 1-one (PYNAP).
Abstract: Co-facial stacking can result in aggregation-caused quenching (ACQ) in conjugated organic luminogens. This study provides an attractive 'slip-stack' self-assembly approach which can eliminate the occurrence of ACQ. The obtained results from steady-state and time-resolved optical studies, along with X-ray diffraction and computational studies demonstrate aggregation-induced emission enhancement (AIEE) of a donor-π-acceptor based 1,3-diarylpropynone, namely 1-(naphthalenyl)-3-(pyren-1-yl)prop-2-yn-1-one (PYNAP). Unlike the monomer, which exhibits poor photoluminescence in solution (φf =2 % in ACN), the twisted manifold of PYNAP allows the orientation of the molecules in a slip-stack fashion during the course of aggregation, which not only avoids a direct co-facial arrangement, but also induces augmented rigidity, leading to restricted intramolecular rotation (RIR) and enhanced emission quantum yield (φf =5 % in ACN/H2 O). The aggregation behavior of PYNAP's congener, 1-phenyl-3-(pyren-1-yl)prop-2-yn-1-one (PYPH) reinforces the hypothesis that slip-stack assembly is a useful strategy for AIEE in polycyclic hydrocarbon luminogens.

14 citations


Journal ArticleDOI
TL;DR: Semiconductor quantum dot composites are promising materials for photovoltaics and photocatalysis because of efficient charge extraction and transport property of graphene as mentioned in this paper. But their performance is limited.
Abstract: Semiconductor quantum dot (QD)–graphene composites are promising materials for photovoltaics and photocatalysis because of efficient charge extraction and transport property of graphene. Analysis o...

12 citations


Journal ArticleDOI
TL;DR: In this paper, a multifunctional/synergistic process, which sequesters Cu2+ while also providing additional functionalities (say a..., was proposed to solve the problem of copper contamination.
Abstract: Copper contamination is a serious ecological and human health hazard. Therefore, a multifunctional/synergistic process, which sequesters Cu2+ while also providing additional functionalities (say a ...

10 citations


Journal ArticleDOI
TL;DR: Self-assembly of three novel poly(aryl ether) dendron derivatives that contain rhodamine units was used to investigate the effect of hydrophobicity on the intracellular uptake of self-assembled fluorophores, and the results suggest that monomer hydophobicity plays an important role in the uptake.

2 citations