Study on novel biphenyl chalcone scaffolds: A dual spectroscopic approach for efficient sensing of hydrazine with low concentration (original) (raw)
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A simple Schiff base as selective and sensitive fluorescent-colorimetric hydrazine chemosensor
International Journal of Environmental Analytical Chemistry, 2018
A new fluorescent-colorimetric chemosensor L has been synthesised by Schiff base condensation reaction between 1,8-diaminooctane and 4-nitro-benzaldehyde in very good yields. Its photo-luminescent properties and selective detection properties for hydrazine have been examined. The synthesised chemosensor exhibited highly selective fluorescence on-off response for hydrazine amongst a wide range of different metal cations, anions and amines, along with the bare eye colour change from colourless to yellow based on intermolecular hydrogen-bond interaction. The limit of detection of the chemosensor L was estimated as 9.77 × 10 −8 M or 3.12 × 10 −6 g L −1 for hydrazine which is extremely below the limit set by the World Health Organization (WHO) and the binding stoichiometry was proposed to be 1 : 2 based on 1 H NMR spectroscopic techniques and the Job's plot analysis. The proposed sensing mechanism is the hydrogenbonding interaction which has further been established by Density Functional Theory (Functional Density Theory (DFT)) studies. This recognition feature of sensor L makes it an efficient chemosensor for hydrazine detection in different water samples.
RSC Advances, 2014
A fluorescein based reactive probe has been designed and synthesized to detect hydrazine selectively over other common analytes. We used here 4-bromobutyrate as a masking unit of fluorescein dye. Hydrazine plays here the role of a de-masking agent to set free the fluorescein dye through a simultaneous substitution-cyclisation-elimination process. This leads to 'turn on' fluorescence with easily discernible color change with a fast response time (<15 minutes).
Analytical Chemistry, 2017
A pair of pyrene-and anthracene-based turn-on fluorescent probes (1 and 2, respectively) reported here can be easily synthesized in a single-step process and also exhibit outstanding sensing behavior toward hydrazine over various competing nucleophilic species and environmentally relevant ions. The probes display dramatic enhancements in the emission intensity with as high as 83-and 173-fold increases in the presence of hydrazine. Nitrogenous bases, thiols, and lanthanides do not interfere in the fluorometric detection. These probes enable the detection of hydrazine with the naked eye well below sub-ppm concentrations (ca. 30 ppb) with analytical detection limits of 5.4 ppb for 1 and 7.7 ppb for 2, which are far exceeded by the accepted lower limit for hydrazine (10 ppb) set by the US EPA. Simple paper strips based on these probes could be used for the detection of hydrazine even in the gas phase. Both of the probes could selectively detect hydrazine even in pond water samples efficiently. The probes were successfully applied to visualize, for the first time, accumulation of hydrazine in live fruit-fly larvae using epifluorescence microscopy. The novel and interesting detection mechanism, proposed on the basis of spectroscopic evidence and single crystal XRD results, indicates that the detection pathway proceeds via the initial step of a five-membered ring formation upon attack of the hydrazine, followed by a dehydration step for gaining aromaticity.
Inorganica Chimica Acta, 2012
A family of emissive acyclic ligands (1-4) and their Cu 2+ and Zn 2+ metal complexes has been synthesized and characterised by microanalysis, IR, MALDI mass spectrometry, UV-Vis and fluorescence emission. For comparative purposes, the coordination ability of all chemosensors (1-4) towards the same metal ions was explored in solution (with the help of the UV-Vis and emission spectroscopy) and in gas phase (by MALDI mass spectrometry). The formation of mononuclear complexes with two or three units of ligands was observed during the entire process.
Solvatochromic hydrazone anions derived from chalcones
Dyes and Pigments, 2008
Recebido em 5/12/05; aceito em 30/3/06; publicado na web em 26/9/06 An undergraduate organic lab experiment is described based on the preparation of two readily accessible hydrazones. The UVvisible spectra of these N-H acids and of their conjugate bases are employed to illustrate the importance of through-conjugation in determining their acid strength and their internal charge-transfer-band transitions.
Analytical chemistry, 2017
A pair of pyrene and anthracene-based turn-on fluorescent probes (1 and 2 respectively) reported here can be easily synthesised in a single-step process and also exhibit outstanding sensing behaviour towards hydrazine over various competing nucleophilic species and environmentally relevant ions. The probes display dramatic enhancements in the emission intensity with as high as 83- and 173-fold increase in the presence of hydrazine. Nitrogenous bases, thiols and lanthanides do not interfere in the fluorometric detection. These probes enable the detection of hydrazine with naked eye well below the sub-ppm concentrations (ca. 30 ppb) with analytical detection limits of 5.4 ppb for 1 and 7.7 ppb for 2, which far exceeds the accepted lower limit for hydrazine (10 ppb) set by the US-EPA. Simple paper strips based on these probes could be used for the detection of hydrazine even in the gas-phase. Both the probes could selectively detect hydrazine even in pond water samples efficiently. The...
Theoretical Studies of Structure, Spectroscopy, and Properties of a New Hydrazine Derivative
Journal of Chemistry, 2013
We will report a combined experimental and theoretical study on molecular structure, vibrational spectra, and energies of (E)-1-(2,4-dinitrophenyl)-2-[(4-methylphenyl)methylidene]hydrazine (1). The molecular geometry and vibrational frequencies and energies in the ground state are calculated by using HF and DFT levels of theory with 6-311G basis sets. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. The harmonic vibrational frequencies were calculated, and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed bar-type spectrograms.
Photophysical Behavior and Sensing Response of Chalcone Containing Pyrene moiety
Delta Journal of Science, 2021
D-π-A dye composed of pyrene and thiophene units was synthesized and characterized using elemental, FT-IR, and mass analyses. The solvatochromic response was investigated in different solvents of various polarities. Additionally, the inclusion characteristic of the investigated dye was studied in different organized assemblies of three surfactants. The spectral changes suggested that the dye would be useful to study the critical micelle concentrations of the studied assemblies systems. Furthermore, the absorption and emission spectra are sensitive towards H + , Co 2+ , Ni 2+ , Cd 2+ , Pb 2+ , and Zn 2+ ions owing to acido-and metallo-chromic behaviors. These results suggest that the investigated dye would be potential candidate for polarity sensors, probe to characterize microenviromental polarity of the surfactants, and sensor for metal ions and H + proton.
Journal of Chemistry
New tricyanofuran intramolecular charge transfer dyes comprising the hydrazone group were prepared and fully characterized in order to study their possible solvatochromism, dyeing ability, and antimicrobial activity. The preparation of the hydrazone dyes was achieved in relatively good yields starting from different aromatic amines. The hydrazone functional group was presented via the azo-coupling reaction of the tricyanofuran compound by the properly substituted diazonium chloride. Chemical structures of the prepared hydrazones were confirmed via nuclear magnetic resonance spectroscopy (1H- and 13C-NMR), Fourier-transform infrared spectroscopy (FT-IR), and elemental analysis (C, H, and N). The UV-visible absorption spectra of the produced sensor colorants displayed interesting solvatochromism in solvents with a different polarity, which was found to be affected by the substituents bonded to the aromatic hydrazone moiety. The pH molecular switching was investigated through tuning th...