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Akella Sivaramakrishna

Bio: Akella Sivaramakrishna is an academic researcher from VIT University. The author has contributed to research in topics: Reactivity (chemistry) & Catalysis. The author has an hindex of 21, co-authored 107 publications receiving 1269 citations. Previous affiliations of Akella Sivaramakrishna include Andhra University & Ben-Gurion University of the Negev.


Papers
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TL;DR: Analysis of the ability of Pseudomonas putida to degrade aflatoxin B 1 showed that AFB 1 was bio-transformed to structurally different compounds, with the modified furan and lactone ring on the AFB 1 molecule.

115 citations

Journal ArticleDOI
TL;DR: A review of the different types of ionic liquids used for the stabilization of metal NPs can be found in this paper, where the authors provide an insight into the various types of imidazolium-based ILs, supported ILs and polyelectrolytes used so far.
Abstract: Metal nanoparticles (NPs) are a subject of global interest in research community due to their diverse applications in various fields of science. The stabilization of these metal NPs is of great concern in order to avoid their agglomerization during their applications. There is a huge pool of cations and anions available for the selection of ionic liquids (ILs) as stabilizers for the synthesis of metal NPs. ILs are known for their tunable nature allowing the fine tuning of NPs size and solubility by varying the substitutions on the heteroatom as well as the counter anions. However, there has been a debate over the stability of metal NPs stabilized by ILs over a long period of time and also upon their recycling and reuse in organocatalytic reactions. ILs covalently attached to solid supports (SILLPs) have given a new dimension for the stabilization of metal NPs as well as their separation, recovery, and reuse in organocatalytic reactions. Poly(ILs) (PILs) or polyelectrolytes have created a significant revolution in the polymer science owing to their characteristic properties of polymers as well as ILs. This dual behavior of PILs has facilitated the stabilization of PIL-stabilized metal NPs over a long period of time with negligible or no change in particle size, stability, and size distribution upon recycling in catalysis. This review provides an insight into the different types of imidazolium-based ILs, supported ILs, and PILs used so far for the stabilization of metal NPs and their applications as a function of their cations and counter anions.

101 citations

Journal ArticleDOI
TL;DR: The role of poly(ionic liquids) is prominent as carriers towards reversible "solubility switch" of synthesized metal nanoparticles between aqueous and organic media by simple anionic metathesis as discussed by the authors.

70 citations

Journal ArticleDOI
TL;DR: The results suggested that P. putida 1274 strain would be a suitable aspirant for bioremediation of nitro-aromatic compounds contaminated sites in the environment.
Abstract: p-Nitrophenol (PNP) occurs as contaminants of industrial effluents and it is the most important environmental pollutant and causes significant health and environmental risks, because it is toxic to many living organisms. Nevertheless, the information regarding PNP degradation pathways and their enzymes remain limited. To evaluate the efficacy of the Pseudomonas Putida 1274 for removal of PNP. P. putida MTCC 1274 was obtained from MTCC Chandigarh, India and cultured in the minimal medium in the presence of PNP. PNP degradation efficiency was compared under different pH and temperature ranges. The degraded product was isolated and analyzed with different chromatographic and spectroscopic techniques. P. putida 1274 shows good growth and PNP degradation at 37°C in neutral pH. Acidic and alkali pH retarded the growth of P. putida as well as the PNP degradation. On the basis of specialized techniques, hydroquinone was identified as major degraded product. The pathway was identified for the biodegradation of PNP. It involved initial removal of the nitrate group and formation of hydroquinone as one of the intermediates. Our results suggested that P. putida 1274 strain would be a suitable aspirant for bioremediation of nitro-aromatic compounds contaminated sites in the environment.

58 citations

Journal ArticleDOI
TL;DR: A new Th4+ ion-selective chromogenic sensor (L) was developed by reacting 1,10-phenanthroline-2,9-dicarbohydrazide with 2-hydroxy naphthaldehyde and has been well integrated with a smartphone RGB color value to make it an analytical signal for real-time analysis of Th4+, with the detection limit down to 116 nM.
Abstract: In this paper, a new Th4+ ion-selective chromogenic sensor (L) was developed by reacting 1,10-phenanthroline-2,9-dicarbohydrazide with 2-hydroxy naphthaldehyde. The sensing ability of L toward Th4+ was investigated in solution and paper strips loaded with L using spectrophotometric and colorimetric methods. The selective interaction of L was examined with various f-metal ions and other selected metal ions from s-block and d-block elements. Results show that by the colorimetric method in solution-phase dimethyl sulfoxide/H2O (7:3, v/v) and paper strip methods, the naked-eye detectable color change of L occurred from colorless solution to yellow-orange and pale yellow colour upon interacting with Th4+ and Al3+, respectively, whereas other metal ions did not interfere. The ligand L exhibits two absorbance bands at 320 and 375 nm because of ligand-to-ligand charge transfer. Upon interaction with Th4+, L undergoes red shift of both absorption bands and the formation of a new UV-vis band at 335 and 440 nm. The UV-visible spectral studies indicate the formation of a 1:1 host-guest complex between L and Th4+ with an association constant of 4.7 × 103 M-1. The limit of quantification and limit of detection of L for the analysis of Th4+ are found to be 167 and 50 nM, respectively. The visually detectable color change of L has been well integrated with a smartphone RGB color value to make it an analytical signal for real-time analysis of Th4+ with the detection limit down to 116 nM. Besides, L was applied for the analysis of Th4+ content present in various real water samples, monazite, and lantern mantle samples by spectrophotometry and RGB color values. The binding mode of L with Th4+ is investigated by 1H NMR, electrospray ionization-mass, and theoretical studies.

55 citations


Cited by
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TL;DR: The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems.
Abstract: Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in ...

1,065 citations

Journal ArticleDOI
TL;DR: Novel chemical structures, different synthetic strategies and controllable morphologies are introduced as a supplement to PIL systems already reported, and the primary properties determining applications, such as ionic conductivity, aqueous solubility, thermodynamic stability and electrochemical/chemical durability are discussed.
Abstract: We review recent works on the synthesis and application of poly(ionic liquid)s (PILs). Novel chemical structures, different synthetic strategies and controllable morphologies are introduced as a supplement to PIL systems already reported. The primary properties determining applications, such as ionic conductivity, aqueous solubility, thermodynamic stability and electrochemical/chemical durability, are discussed. Furthermore, the near-term applications of PILs in multiple fields, such as their use in electrochemical energy materials, stimuli-responsive materials, carbon materials, and antimicrobial materials, in catalysis, in sensors, in absorption and in separation materials, as well as several special-interest applications, are described in detail. We also discuss the limitations of PIL applications, efforts to improve PIL physics, and likely future developments.

734 citations

Journal ArticleDOI
TL;DR: The influence of N-aryl functionality investigated by Killian et al. shows that the selectivity was mainly dependent upon the steric bulk attached to nitrogen, and less so on the group's basicity.
Abstract: Recent advances in the area of Olefin Oligomerization via metallacycles that include dimerization, trimerization, tetramerization, and beyond, are reviewed. Studies have found that metallacyclopentane decomposition to 1-butene many not be particularly facile due to the absence of metallacycle expansion. Follow-up studies concentrated on the N-H functionality and the Cr oxidation state and role of MAO show that activities and selectivities to 1-hexene are similar to the original Cr(III) complexes. Nenu and Weckhuysen prepared silica-supported triazacyclohexane complexes, by treating the reduced Phillips polymerization catalyst with triazacyclohexane ligands in dichloromethane. The influence of N-aryl functionality investigated by Killian et al. shows that the selectivity was mainly dependent upon the steric bulk attached to nitrogen, and less so on the group's basicity.

492 citations

Journal ArticleDOI
TL;DR: This review provides a concise overview of the current methods for the generation and accumulation of cationic reactive intermediates as a pool using modern techniques of electrochemistry and their reactions with subsequently added nucleophilic reaction partners.
Abstract: Electrochemistry serves as a powerful method for generating reactive intermediates, such as organic cations. In general, there are two ways to use reactive intermediates for chemical reactions: (1) generation in the presence of a reaction partner and (2) generation in the absence of a reaction partner with accumulation in solution as a “pool” followed by reaction with a subsequently added reaction partner. The former approach is more popular because reactive intermediates are usually short-lived transient species, but the latter method is more flexible and versatile. This review focuses on the latter approach and provides a concise overview of the current methods for the generation and accumulation of cationic reactive intermediates as a pool using modern techniques of electrochemistry and their reactions with subsequently added nucleophilic reaction partners.

381 citations