Narinder Singh

Panjab University, Chandigarh, Chandigarh, India

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Publications (152)473.57 Total impact

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    ABSTRACT: A novel chemosensor based on metal complex of fluorescent organic nanoparticles (FONs) of new receptor (1) with ferric ions has been developed through simple synthetic procedure. The prepared receptor and its complex with ferric ions were subjected to FONs using re-precipitation method. FONs (N1) and FONs-Fe3+ ensemble (N1.Fe3+) were characterized using various techniques such as NMR, EDAX and DLS. The N1.Fe3+ were further investigated for their sensor properties and found them selective for determination of tyramine and 4,6-diamino-2-mercaptopyrimidine, having no interference from any other biogenic amines or biothiols. N1.Fe3+ showed a detection limit as low as 4.95 nM and 3.02 nM respectively for tyramine and 4,6-diamino-2-mercaptopyrimidine, fulfilling the concept of “Single receptor multianalyte determination”.
    Sensors and Actuators B Chemical 12/2015; 220:295-301. DOI:10.1016/j.snb.2015.05.086 · 4.29 Impact Factor
  • Amanpreet Singh · Jasminder Singh · Narinder Singh · Doo Ok Jang
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    ABSTRACT: Abstract
    Tetrahedron 09/2015; 71(36):6143-6147. DOI:10.1016/j.tet.2015.06.096 · 2.82 Impact Factor
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    ABSTRACT: The ruthenium complex with (N,N,N-tris(benzimidazol-2yl-methyl)amine, L(1)) was prepared, and characterized. Fukui data were used to localize the reactive sites on the ligand. The structural and electronic properties of the complex were analyzed by DFT in different oxidation states in order to evaluate its oxidant properties for phenol oxidation. The results show that the hard Ru(IV) cation bonds preferentially with a hard base (Namine = amine nitrogen, or axial chloride ion), and soft Ru(II) with a soft base (Nbzim = benzimidazole nitrogen or axial triphenyl phosphine). Furthermore, the Jahn-Teller effect causes an elongation of the axial bond in the octahedral structure. The bonding nature and the orbital contribution to the electronic transitions of the complex were studied. The experimental UV-visible bands were interpreted by using TD-DFT studies. The complex oxidizes phenol to benzoquinone in the presence of H2O2 and the intermediate was detected by HPLC and (13)C NMR. A possible mechanism and rate law are proposed for the oxidation. The adduct formation of phenol with [Ru(O)L(1)](2+) or [Ru(OH)L(1)](+) is theoretically analyzed to show that [Ru(OH)L(1)-OPh](+) could produce the phenol radical. Graphical Abstract Phenol oxidation by ruthenium complex.
    Journal of Molecular Modeling 09/2015; 21(9):2759. DOI:10.1007/s00894-015-2759-1 · 1.87 Impact Factor
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    ABSTRACT: A Schiff-base receptor bearing different functionalities was synthesized from dipicolinic acid hydrazide and characterized with several spectroscopic techniques. To explore its practical application as a sensor, the receptor was processed into organic nanoaggregates (O1) in aqueous medium by the reprecipitation method. The O1 nanoaggregates were characterized by techniques such as dynamic light scattering and TEM, and their recognition properties for metal ions were investigated by fluorescence spectroscopy. The nanoaggregates showed selectivity for Cu2+ over other metal ions. The structure of the complex O1·Cu2+ thus formed was determined by single-crystal X-ray crystallography. Complex O1·Cu2+ was further employed as a sensor for detection of biogenic amines in aqueous medium, and showed selective sensing of spermine with a detection limit of 7.62 nM. The color change on addition of spermine to the complex can be seen with the naked eye. Moreover, stability in the physiological pH range and negligible effect of ionic environment provided the opportunity for real-time application of the sensor in aqueous medium.
    Berichte der deutschen chemischen Gesellschaft 08/2015; DOI:10.1002/ejic.201500489
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    ABSTRACT: A new receptor 3-((2-(1H-benzo[d]imidazol-2-yl)phenylimino)methyl)benzene-1,2-diol (1) was synthesised and developed as a highly selective fluorescent chemosensor for the detection of Hg2+ in semi-aqueous media. The fluorescence of receptor 1 was dramatically and selectively quenched on complexation with Hg2+ ion with the detection limit down to 0.20 μM. The developed sensor was successfully applied for the determination of Hg2+ content in water samples. Density Functional Theory (DFT) calculations were performed to study the mechanistic behaviour behind the binding of Hg2+ with receptor 1.
    Supramolecular Chemistry 08/2015; 27(7-8). DOI:10.1080/10610278.2015.1023303 · 2.13 Impact Factor
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    ABSTRACT: A novel pyrrole-substituted salicylimine zinc (II) ion complex has been synthesized and evaluated its anion binding affinity. The probe 4 has high selectivity for HSO4 (-) over other anions in CH3OH:H2O (70:30, v/v) solvent system. The emission intensity of 4 was quenched upon addition of HSO4 (-). The probe 4 is highly selective for HSO4 (-) with a detection limit of 40 nm. Photoinduced electron transfer (PET) is responsible for observed change. The binding affinity of 4 for HSO4 (-) was further authenticated through ratiometric change in absorbance profile.
    Journal of Fluorescence 07/2015; DOI:10.1007/s10895-015-1599-9 · 1.67 Impact Factor
  • Hemant Sharma · Navneet Kaur · Narinder Singh · Doo Ok Jang
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    ABSTRACT: A solvent-free selective green synthesis of 1,2-disubstituted benzimidazoles was developed using a ball-milling technique. Recyclable ionic liquid-coated ZnO-nanoparticles (Zn-NPs, Catalyst 5) was employed as a catalyst, which produced high yields, turnover number and turnover frequency because of synergetic catalytic properties of ionic liquid and ZnO-NPs. The present method successfully employed the synthesis of various 1,2-disubstituted benzimidazole derivatives in excellent yields with high selectivity. The reaction could also be performed at a multi-gram scale with the same efficiency. A high eco-scale score and low E-factor emphasize the ecofriendly nature of the present method.
    Green Chemistry 06/2015; DOI:10.1039/C5GC00536A · 6.85 Impact Factor
  • Jasminder Singh · Ajnesh Singh · Manisha Yadav · Narinder Singh
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    ABSTRACT: Schiff base based tripodal receptor was synthesized and was complexed with zinc metal ion (n17) using very easy single step process. The resulting complex was fully characterized by CHN and single crystal XRD. The real time application of the complex in aqueous media was devised by preparing its ONP and their sensor activity was tested with various anions by observing changes in fluorescence profile of n17. It was observed that ONP of n17 responded excellently for fluoride and sulfate producing two different signals, with a detection limits of 4.84 × 10-12 M and 5.67 × 10-9 M respectively, without having any interference from each other. The real time application of the sensor was also tested using various samples collected from various daily utility items and found to respond exceptionally well.
    Dalton Transactions 05/2015; 44(28). DOI:10.1039/C5DT01063B · 4.20 Impact Factor
  • Tilak Raj · Beant Kaur · Navneet Kaur · Narinder Singh
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    ABSTRACT: Substituted dihydropyrimidone derivatives were synthesized through the one pot multicomponent Zn(ClO4)2 catalysed Biginelli reactions between differently substituted aromatic aldehydes, urea and ethylacetoacetate. Purified products were characterized and further engineered into metal inorganic conjugates of silver, copper and gold. Size, morphology and stability of nanoaggregates were analysed using FTIR, EDX, TEM, XRD and TGA analysis. Antimicrobial activities of all the synthesized compounds and their metal conjugates were evaluated against various bacterial and fungal strains. Results of investigations revealed that metal nanoaggregate Au@4c has shown maximum inhibition of MIC 8 against bacteria S. Aureus. Further, bacterial SEM cell imaging carried out against S. Aureus before and after treatment of Au@4c advocates that formation of belbs due to the accumulation of the cytoplasm are possible cause of bacterial cell death.
    RSC Advances 05/2015; 5(58). DOI:10.1039/C5RA08765A · 3.84 Impact Factor
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    ABSTRACT: TiO2 and its hybrid TiO2-Fe3O4 NPs were prepared, and doped with Ag, or Au NPs to yield TiO2-Fe3O4-Ag NPs and TiO2-Fe3O4-Au NPs. The photo-catalytic oxidation of phenols by the above materials were analyzed under both solar and UV light. For TiO2-Fe3O4-Ag NPs and TiO2-Fe3O4-Au NPs considerable visible light photo-oxidation was observed, while for other nano-materials UV-light energy required. The materials having Fe3O4 were reused after isolation by magnets. The oxidation rate decreases from phenol to 2,4,6-trichlorophenol in agreement with the Hammett plot, and follows first order kinetics in the substrate, for which a possible mechanism is proposed. The effect of pH, and solvents were also analyzed in the oxidation. To further support our kinetics experiments, Density functional theory (DFT) calculation were performed to predict the rate limiting step of phenol oxidation to yield benzoquinone.
    Separation and Purification Technology 05/2015; 149. DOI:10.1016/j.seppur.2015.05.019 · 3.07 Impact Factor
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    ABSTRACT: A novel receptor (E)-1-(phthalazine-4-yl)-2-(1-(pyridine-2-yl)ethylidene) hydrazine (3) was developed for the detection of trace water content present in methanol. Upon interaction of water molecule with receptor 3, there appears a significant color change from colorless to yellow green and the absorption band at 355 nm was shifted to 435 nm (i.e. bathochromic or red shift) due to selective encapsulation of water molecule at 1-(pthalazine-4-yl) hydrazine-NH and imine groups leading to tautomeric transformation in the ground state which is caused by an intramolecular proton transfer. Also, there was remarkable enhancement in fluorescence intensity of 3 in methanol upon addition of water. Thus the chemosensor 3 has been developed for chromogenic and fluorogenic investigation of water and the detection limit is 5 ppm in methanol.
    Sensors and Actuators B Chemical 04/2015; 210. DOI:10.1016/j.snb.2014.12.126 · 4.29 Impact Factor
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    ABSTRACT: A highly selective and sensitive colorimetric nanosensor driven by Cu2+ ion for iodide (I–) ion was developed using citrate-capped AgNPs. This assay relied upon the distance-dependent optical properties of AgNPs where Cu2+ was employed as interlinking agent. In the simultaneous presence of I− and Cu2+, the system showed a color change from yellow to colorless that could be monitored using naked-eyes and UV–vis spectrophotometer. The nanosensor exhibited good iodide sensitivity with a detection limit of 0.24 μM. Further, the nanosystem was developed as an AND type logic gate with the inputs of Cu2+ and I−.
    Materials Letters 04/2015; 145. DOI:10.1016/j.matlet.2015.01.072 · 2.27 Impact Factor
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    ABSTRACT: Organic nanoparticles (ONPs) of lipoic acid and its doped derivatives ONPs/Ag and ONPs/Au were prepared and characterized by UV-Visible, EDS, and TEM analysis. The antibacterial properties of the ONPs ONPs/Ag and ONPs/Au were tested against bacterial strains (Staphylococcus aureus, Bacillus cereus, Escherichia coli and Salmonella typhi). Minimal Inhibitory Concentration (MIC) and bacterial growth inhibition tests show that ONPs/Ag are more effective in limiting bacterial growth than other NPs, particularly, for Gram positive than for Gram-negative ones. The order of bacterial cell growth inhibition was ONPs/Ag > ONPs > ONPs/Au. The morphology of the cell membrane for the treated bacteria was analyzed by SEM. The nature of bond formation of LA with Ag or Au was analyzed by molecular orbital and density of state (DOS) using DFT.
    Molecules 04/2015; 20(4):6002-6021. DOI:10.3390/molecules20046002 · 2.42 Impact Factor
  • Hemant Sharma · Navneet Kaur · Narinder Singh
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    ABSTRACT: In recent years, the field of molecular recognition is extensively developed due to need of efficient method for detection of various biological and environmental important analytes (metal ions, anions and biomolecules). A number of literature reports advocate nano-molar detection of analytes. The major concern with most of chemosensors is solubility in an aqueous medium. This critical review mainly focuses on the detection of analytes (metal ions, anions and biomolecules) in an aqueous medium. Various mechanisms like cation displacement assay, anion displacement assay, anion ligand exchange, aggregation-caused quenching (ACQ), aggregation-induced emission (AIE), hydrogen bonding mechanism and analyte-induced reaction mechanism are discussed. Based upon mechanism, the relationship between structure and properties are derived. Afterwards, a discussion on the current state-of-the-art in metal ions/ anions/biomolecules sensing in an aqueous medium, includes design of ligand, preorganization in molecules, detection method and its application. Finally, future perspectives of detection in an aqueous medium in the field of molecular recognition are discussed.
    Analytical methods 03/2015; DOI:10.1039/C5AY00483G · 1.94 Impact Factor
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    ABSTRACT: A dipodal naphthalimide based receptor 1 was synthesized, characterized and processed into organic nanoparticles (N1) using single step re-precipitation technique. These organic nanoparticles were further used as a platform for the development of hybrid organic-inorganic framework (H1). Hybrid nanoparticles thus formed were evaluated for their photo-physical behavior and their interaction with various available drugs using fluorescence spectroscopic technique and found it selective in determination of amoxicillin in aqueous medium. Competitive binding studies further confirmed the selectivity of H1 for amoxicillin, as no interference was perceived with any other drug in determination of amoxicillin. H1 was able to determine amoxicillin quite efficiently in commercially available tablets of the drug with a lowest detection limit of 236 nM.
    Sensors and Actuators B Chemical 03/2015; 209:524-529. DOI:10.1016/j.snb.2014.12.018 · 4.29 Impact Factor
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    Gaganpreet Kaur · Tilak Raj · Narinder Singh · Navneet Kaur
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    ABSTRACT: Pyrimidine based sensor (1) has been synthesized through the facile one pot reaction of pyrrole-2-carboxaldehyde, 2-aminobenzimidazole and 1, 3-dimethylbarbituric acid in methanol using few drops of HCl as a catalyst. Product 1 was characterized spectroscopically. Further, Compound 1 was fabricated to its organic nanoparticles (N1) and characterized using DLS and SEM. Nanoaggregates N1 was further evaluated for the photo physical studies against gram +ve and gram -ve bacteria. It was observed that nanoaggregates N1 selectively enhance the fluorescence intensity in the presence of gram (–ve) bacteria Pseudomonas Aeruginosa with the detection limit of 4.6 CFU. To the best of our knowledge, this study is the first report on the use of fluorescent nano-aggregates of pyrimidine derivative 1 for the detection of bacteria Pseudomonas Aeruginosa in various samples
    Organic & Biomolecular Chemistry 03/2015; 13(16). DOI:10.1039/C5OB00206K · 3.49 Impact Factor
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    ABSTRACT: Luminescent sensors and switches continue to play a key role in shaping our understanding of key biochemical processes, assist in the diagnosis of disease and contribute to the design of new drugs and therapies. Similarly, their contribution to the environment cannot be understated as they offer a portable means to undertake field testing for hazardous chemicals and pollutants such as heavy metals. From a physiological perspective, the Group I and II metal ions are among the most important in the periodic table with blood plasma levels of H(+), Na(+) and Ca(2+) being indicators of several possible disease states. In this review, we examine the progress that has been made in the development of luminescent probes for Group I and Group II ions as well as protons. The potential applications of these probes and the mechanism involved in controlling their luminescent response upon analyte binding will also be discussed.
    Chemical Society Reviews 03/2015; 44(13). DOI:10.1039/c4cs00365a · 30.43 Impact Factor
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    ABSTRACT: Organic nanoparticles (ONPs) of N,N'-ethylenebis(salicylimine) (salen) were synthesized and applied for specific recognition of Zn(2+) and Al(3+) ions in an aqueous medium. The results show that fluorescence intensity rises with the increasing concentration of Zn(2+) in salen solution, proving that salen-ONPs detect Zn(2+) efficiently in the aqueous medium as chemo-sensor. Furthermore, the salen-ONPs/Zn(2+) system performs as an ON-OFF switch between pH 6.0 and 4.0. Amusingly, although salen-ONPs/Al(3+) does not show any significant effect in the fluorescence spectra, highest fluorescence intensity was observed when Al(3+) ion was added to salen-ONPs/Zn(2+) in a sequential order (addition of Zn(2+) to salen-ONPs, followed by Al(3+)). This system can be applied as a novel three inputs logic gate supported by the fluorescence for the detection of Zn(2+) and Al(3+) in biological and environmental samples. It appears that photo induced electron transfer (PET) occurs in the salen-ONPs when the fluorophore is excited. For salen/Zn(2+) system, the PET is being inhibited considerably by lowering the receptor HOMO energy due to the formation of a bond between the metal ion and ligand, enhancing the fluorescence emission. This is consistent with the theoretical study that the energy of HOMO of the ligand is lower than that of Zn(salen)(2+) complex. Copyright © 2015 Elsevier B.V. All rights reserved.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2015; 146. DOI:10.1016/j.saa.2015.03.082 · 2.13 Impact Factor
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    ABSTRACT: Cation sensing behaviour of a pyrrole-based derivative (2-hydroxyl 3 methyl 6 isopropyl benzaldehyde}-3,4-dimethyl-1H-pyrrole-2-carbohydrazide (receptor 3) has been explored and is found to be selective towards Zn(2+) over a variety of tested cations. The receptor 3 has shown high selectivity and sensitivity towards Zn(2+) over the other alkali, alkaline earth and transition metal ions. In the presence of Zn(2+) , absorption band of receptor 3 has shown the red shift. The sensing behaviour has been suggested to continue via enhancement process which has further been supported by UV-vis absorption and theoretical density functional theory (DFT) calculations indicating the formation of a 1:1 complex between the pyrrole based receptor 3 and Zn(2+) . The present work is presenting a highly selective dual channel colorimetric sensor for zinc with great sensitivity. The developed sensor was successfully applied to image intracellular Zn(2+) in living cells. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    Journal of Molecular Recognition 02/2015; 28(6). DOI:10.1002/jmr.2451 · 2.34 Impact Factor
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    ABSTRACT: A fluorescent based receptor (4Z)-4-(4-diethylamino)-2-hydroxybenzylidene amino)-1,2dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (receptor 3) was developed for the highly selective and sensitive detection of Cu(2+) and Zn(2+) in semi-aqueous system. The fluorescence of receptor 3 was enhanced and quenched, respectively, with the addition of Zn(2+) and Cu(2+) ions over other surveyed cations. The receptor formed host-guest complexes in 1:1 stoichiometry with the detection limit of 5nM and 15nM for Cu(2+) and Zn(2+) ions, respectively. Further, we have effectively utilized the two metal ions (Cu(2+) and Zn(2+)) as chemical inputs for the manufacture of INHIBIT type logic gate at molecular level using the fluorescence responses of receptor 3 at 450nm. Copyright © 2015 Elsevier B.V. All rights reserved.
    Analytica Chimica Acta 02/2015; 872. DOI:10.1016/j.aca.2015.02.051 · 4.52 Impact Factor

Publication Stats

1k Citations
473.57 Total Impact Points

Institutions

  • 2014–2015
    • Panjab University
      • Centre for Nanoscience and Nanotechnology
      Chandigarh, Chandigarh, India
  • 2010–2015
    • Indian Institute of Technology Ropar
      • Department of Chemistry
      Rūpar, Punjab, India
  • 2004–2013
    • Guru Nanak Dev University
      • • Department of Pharmaceutical Sciences
      • • Department of Chemistry
      Amritsar, Punjab, India
  • 2008–2010
    • The Robert Gordon University
      • School of Pharmacy and Life Sciences
      Aberdeen, Scotland, United Kingdom
  • 2007–2009
    • Yonsei University
      • • Department of Chemistry
      • • Center for Bioactive Molecular Hybrids
      Sŏul, Seoul, South Korea