A new efficient chemosensor 1 was prepared, for the detection of Fe3+ in solutions as a colorimetric and fluorescent sensor. The visual and fluorescent behaviors of the receptor toward various metal ions were also explored. The receptor shows exclusive response toward Fe3+ ions and also distinguishes Fe3+ from other cations by color change and fluorescence enhancement in hydroalcoholic solution (MeOH/H2O = 9/1, v/v). Thus, the receptor can be used as a colorometric and fluorescent sensor for the determination of Fe3+ ion. The fluorescence microscopy experiments showed that the chemosensor is efficient for detection of Fe3+ in vitro, developing a good image of the biological organelles.
The 2,2′-dinaphtholazobenzene molecular framework (P) was designed, synthesized and characterized. Its absorption and fluorescence properties revealed that P is a dual sensor for copper ions (Cu2+) and fluoride ions (F?) in DMSO. The colorimetric activities were clearly visible by naked eye upon the addition of the two ions. Fluorescence quenching and enhancement were observed when Cu2+ and F? ions were added respectively. Density Functional Theory (DFT) calculations were carried out to provide an insight into the interaction of guest ions (Cu2+ and F?) with P, and to explain how the molecular orbitals were affected.
A bis(naphthalimide-piperazine) derivative (1) was synthesized as a pH-sensitive Off-On fluorescent probe. Operation mechanism of 1 is based on photo-induced electron transfer (PET) and its pH-dependent optical changes were investigated by using absorption and fluorescence spectroscopy. In the pH range of 11–4.5, this probe undergoes PET process from the piperazine to the naphthalimide moiety, leading to a fluorescence quenching. However, in the pH range of 4.5–1, the PET is inhibited to give a fluorescence enhancement. Moreover, the fluorescence ‘turn-on’ response of 1 is highly selective for protons (H+) over other metal cations, biomolecules and it shows a good reversibility between acidic and basic conditions.
Hexadentate ligand L and its Ln3+ complexes EuLCl3 (1), TbLCl3 (2), SmLCl3 (3) are synthesised. All these complexes are well characterized for their photophysical properties such as luminescence lifetime decay(τ) and overall quantum yield(Φ). These complexes being water soluble, depicts their intense metal centred luminescence. Effect of pH on these complexes suggest that their emission intensities are stable in the pH range 4–9 and show their compatibility to function in the physiological pH.
Selective fluorescence turn on Zn2+ sensor with long-wavelength emission and a large Stokes shift is highly desirable in Zn2+ sensing area. We reported herein the synthesis and Zn2+ recognition properties of a new thiosemicarbazone-based fluorescent sensor L. L displays high selectivity and sensitivity toward Zn2+ over other metal ions in DMSO-H2O (1:1, v/v, HEPES 10 mM, pH = 7.4) solution with a long-wavelength emission at 572 nm and a large Stokes shift of 222 nm. Confocal fluorescence microscopy experiments demonstrate that L is cell-permeable and capable of monitoring intracellular Zn2+.
Graphical Abstract We report a new thiosemicarbazone-based fluorescent sensor (L) for selective recognition of Zn2+ with a long wavelength emission and a large Stokes shift.
Nanocomposites with thermo and photo-switchable fluorescent properties were synthesized via mini-emulsion polymerization based on spiropyran and methyl methacrylate monomer. The photophysical behavior of fluorescence nanocomposites was investigated by fluorescence spectrophotometry in different temperature, UV-light and time of exposure. It was found that methyl methacrylate polymer is capable of acting as a protective layer and play a critical role in improving the photostability of colorants. The nanocomposites exhibited excellent fluorescent thermo-switching action with respect to the free spiro molecule.
The solvatochromic 9-hydroxybenzo[b]quinolizinium ion is shown to operate as fluorescent probe for the detection of water in acetonitrile. The dual fluorescence of this photoacid and its dependence on the content of water in the medium enable the ratiometric analysis of the fluorescence data.
Solvent free synthesis of 6,7-dihydroxy-3-(3-chlorophenyl) coumarin (CFHC) was designed and obtained by the interaction of 2-(2,4,5-trimethoxyphenyl)-1-(3-chlorophenyl)acrylonitrile with pyridinium hydrochloride in the presence of silica gel by using microwave irradiation. The characterization of CFHC was confirmed by FT-IR, 1H, 13C, 13C–APT and 2D HETCOR spectroscopy methods. The optical behavior of CFHC towards metal ions was investigated by UV-visible and fluorescence spectroscopy. CFHC showed “on–off” type fluorescence response towards Cu2+ with high selectivity in aqueous solution (CH3CN/H2O, 9/1, v/v). Once binding with Cu2+, CFHC-Cu2+ complex also displayed high selectivity for sulfide, resulting in “off–on” type sensing of sulfide anion.
Graphical abstract Visual fluorescence changes upon addition of various metal ions (5.0 eq.) to CFHC in CH3CN/H2O (90:10, v/v) under UV excitation (365 nm)
Due to the deleterious effects of mercury on human health and natural ecosystems, high reactivity, non-degradability, extreme volatility and relative water and tissue solubility, it would consider as one of the most toxic environmental pollutants among the transition metals. In the present investigation, we have tried to summarized the several organic material based fluorescent sensor including rhodamine, boron-dipyrromethene (BODIPYs), thiourea, crown-ether, coumarine, squaraines, pyrene, imidazole, triazole, anthracene, dansyl, naphthalenedimide/ naphthalene/ naphthalimide, naphthyridine, iridium (III) complexes, polymeric materials, cyclodextrin, phthalic anhydride, indole, calix [4]arene, chromenone, 1,8-naphthalimides, lysine, styrylindolium, phenothiazine, thiocarbonyl quinacridone, oxadiazole, triphenylamine–triazines, tetraphenylethene, peptidyl and semicarbazone for the trace mercury detection in the aqueous, aqueous–organic and cellular media. The present review provides a brief look over the previous development in the organic material based fluorescent sensor for mercuric ion detection. Furthermore, the ligand-metal binding stoichiometry, binding/association/dissociation constants and the detection limit by the receptors have been particularly highlighted which might be useful for the future design and development of more sensitive and robust fluorescent chemosensor/chemodosimeter for the mercuric ion detection.
New substituted thieno[3,2-c]pyridine derivatives 5 were synthesized by the reaction of 3-bromo-4-chlorothieno[3,2-c]pyridine 1 with cyclic amine 2, which further on Suzuki reaction with boronic acids 4 converted to corresponding 3-arylthieno[3,2-c]pyridine 5. Substituent R3 has predominant effect on fluorescence properties of thienopyridines. However, the electron donor amine at C4 has no effect on fluorescence properties of thienopyridines.
Graphical Abstract New thieno[3,2-c]pyridine derivatives were synthesized from 3-bromo-4-chlorothieno[3,2-c]pyridine and cyclic amines, which by on Suzuki reaction with boronic acids converted to corresponding 3-arylthieno[3,2-c]pyridine. Substituent R3 has predominant effect on fluorescence properties of thienopyridines. However, the electron donor amine at C4 has no effect on fluorescence properties of thienopyridines
A series of MZr4(PO4)6:Dy3+ (M = Ca, Sr, Ba) phosphors were prepared by the solid state diffusion method. Confirmation of the phase formation and morphological studies were performed by X-ray powder diffraction (XRD) measurements and scanning electron microscopy, respectively. Photoluminescence (PL) properties of these phosphors were thoroughly analyzed and the characteristic emissions of Dy3+ ions were found to arise from them at an excitation wavelength of 351 nm. The PL emission spectra of the three phosphors were analyzed and compared. The CIE chromaticity coordinates assured that the phosphors produced cool white-light emission and hence, they are potential candidates for UV excited white-LEDs (WLEDs).
Two chemiluminescent compounds containing 2,5-di(thien-2-yl)pyrrole and pyridazine units, namely 5,7-di(thiophen-2-yl)-2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione (5) and 6-phenyl-5,7-di(thiophen-2-yl)-2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione (6), were successfully synthesized and electrochemically polymerized. The compounds have chemiluminescent properties and glow in the presence of hydrogen peroxide in basic medium. The intensity of the glow can be increased dramatically by using Fe3+ ions, hemin (1.0 ppm) or blood samples (1.0 ppm) as catalyst. The compounds 5 and 6 have one well-defined irreversible oxidation peak at 1.08 V and 1.33 V vs Ag/AgCl, respectively. Electrochemical polymerization of both 5 and 6 were carried out successfully by repeating potential scanning in the presence of BF3. Et2O in an electrolyte solution of 0.1 M LiClO4 dissolved in acetonitrile. The electronic band gaps (Eg) of the polymers P5 and P6 were found to be 2.02 eV and 2.16 eV, respectively. On the other hand, the corresponding polymers are electroactive and exhibited electrochromic features.
Specific functionalized calix[4]arene based fluorescent chemosensor was synthesized for cations and anions binding efficiency examination. Receptor C4MA displayed strong affinity for Al3+and S2O72? with enhanced fluorescence intensity. The selective response of C4MA was investigated in the presence of different co-existing competing ions. The limit of detection (LOD) of Al3+and S2O72? was calculated as 2.8?×?10?6 M and 2.6?×?10?7 M respectively. Sensor C4MA forms (1:1) stoichiometric complex with both Al3+ and S2O72? and their binding constants were calculated as 12.1?×?104 and 8.3?×?103 respectively. Complexes were also characterized through FT-IR spectroscopy.
Two new Cu(II) complexes with Picolinic acid and Tryptophan [Cu(II)(DPTR)(H2O)2](1:1) (1) and [Cu(II)(DPTR)(Phen)] (1:1:1) (2) were synthesized, characterized and studied their DNA binding, cleavage, docking and anti-cancer properties. The molecular modeling studies were carried out with energy minimized structures of metal complexes. CT-DNA binding studies revealed that the complexes bind through an intercalative mode and show good binding propensity. The docking study also confirms the intercalative mode of binding. The hydrolytic DNA cleavage activity of these complexes has been studied using gel electrophoresis. Complex 2 shows better efficiency than 1. Cell viability experiments indicated that the ligand, complexes show significant dose dependent cytotoxicity in selected cell lines.
Graphical Abstract Two new Cu(II) complexes with Picolinic acid and Tryptophan, [Cu(II)(DPTR)(H2O)2](1:1) (1) and [Cu(II)(DPTR)(Phen)] (1:1:1) (2) were synthesized, characterized and studied their DNA binding, cleavage, docking and anti-cancer properties.
In this paper, we report on the results of spectrofluorimetric study of new fluorescent sensor based on [Zn2L2] doped in ethyl cellulose. The sensor optical signal is based on the rapid fluorescence quenching in the presence of acetone vapor. The acetone vapor detection limit in a gas mixture by means of sensor based on [Zn2L2] doped in ethyl cellulose is 1.68 ppb. Being highly sensitive to the acetone acetone presence, instant in response and easy to use, the sensor can find an application for the noninvasive diagnostics of diabetes as well as for the monitoring of the content of acetone acetone in the air at industrial and laboratory facilities.
Electronic absorption and emission spectra of 3-acetyl coumarin, 3-(bromoacetyl) coumarin and 3-(di bromoacetyl) coumarin have been recorded at room temperature in thirteen solvents with different polarities. Both ground and excited state dipole moments have been calculated for both locally excited and charge transfer transitions by using the solvatochromic method. Excited state dipole moments of all the three compounds are higher than their ground state values. DFT calculations have been profound to estimate their ground and excited state dipole moments. The estimated change in dipole moment by the application of microscopic solvent polarity parameter and bulk solvent polarity methods are in close agreement. Concentration dependent dual fluorescence has been observed in the emission spectra of all the three compounds.
In this study the researcher reports a novel, one step synthesized rod-like nanoparticles of cerium (III)—tetraphenylporphyrin sandwich complex as a spectrofluorometric sensor to measure trace amount of Hg (II) and Cu (II) metal ions. Moreover, the synthesized fluorescent probe was able to detect higher amounts (>10?4 M) of Hg (II) in aqueous media by changing the color which can also be used as a selective mercury naked-eye sensor. The selectivity and sensitivity of the sensor based on its fluorescence quenching in the presence of Hg (II) and Cu (II) were studied according to the Stern-Volmer equation. The detection limit of the sensor was 16 nM for Hg (II) and about 2.34 μM for Cu (II) ions.
Our present investigation aims at the synthesis and application of new, symmetric bridged bis-pyrazolone based acid dyes. The bis-pyrazolone compounds were accomplished from bis- hydrazine of 4,4′-Diaminostilbene-2,2′-disulfonic acid and ethyl acetoacetate. The bis-pyrazolones have been coupled with diazonium salts of o-hydroxyl aromatic amines which resulted in ligand dyes. The intermediate ligand dyes were treated with 3d transition metals to achieve the targeted metal complex acid dyes. The structures of investigated compounds were confirmed with the help of spectroscopic techniques. Dyes were applied on leather and their application parameters including their light fastness, wash fastness and rubbing fastness were determined.
In this paper, the green synthesis of fluorescent carbon dots (CDs) via one-step hydrothermal treatment of cornstalk was investigated. This approach is facile, economical, and effective. The obtained CDs with an average diameter of 5.2 nm possess many excellent properties such as emitting blue fluorescence under UV light (365 nm), high monodispersity, good stability, excellent water dispersibility, and absolute quantum yield of 7.6%. Then, these CDs were used as sensing probes for the detection of Fe2+ and H2O2 with detection limits as low as 0.18 and 0.21 μM, respectively. This sensing platform shows advantages such as high selectivity, good precision, rapid operation, and avoiding the precipitation of iron oxyhydroxides.
Oxazinium derivatives have recently played an important role in bioanalysis attributing to the distinguished properties, thus a detailed study of the structure-property relationship is especially significant. Herein, pH-sensitive optical properties of Nile Blue (1a), N-monoalkyl-Nile Blue (1b) and Azure A (1c) have been carried out in extreme acid and base conditions. Dyes 1a and 1c showed colorimetric changes by the protonation of nitrogen atom in strong acidic condition (pH < 2.0), and dyes 1a ? c exhibited colorimetric changes by equilibrium between amino and imide groups in very strong basic case (pH > 7.6). Besides, their fluorescent properties were closed to ON ? OFF and OFF ? ON emissions at 640–820 nm under strong acidic and basic conditions. Moreover, the absorption and emission properties were reversible, and there were no remarkable optical intensity changes of dyes 1a ? c under subacidic and neutral solutions (pH = 3.0–7.0). The (TD) DFT calculations were used to optimize the most stable structures of their corresponding protonated and deprotonated forms, and their absorption and emission properties were also explained. Their fluorescent properties nearly ON-OFF and OFF ? ON in strong acidic and basic conditions at near-infrared region will give the possible application in pH detection for extreme conditions.
