Jesús Sanmartín Matalobos

Thiophene anchored coumarin derivative as a turn-on fluorescent probe for Cr3+: cell imaging and speciation studies.

A thiophene-coumarin hybrid molecule, (6E)-6-((thiophen-2-yl)methyleneamino)-2H-chromen-2-one (TMC) has been prepared and its single crystal X-ray structure is reported. TMC can selectively detect Cr(3+) in presence of other common cations. Both TMC and its Cr(3+) complex are well characterized by different spectroscopic techniques like (1)H NMR, QTOF-MS ES(+), FTIR and elemental analysis as well. TMC exhibits fluorescence enhancement upon binding Cr(3+) in CH(3)CN-HEPES buffer (0.02 M, pH 7.4) (4:6, v/v) medium. Detection limit of the method is 1 × 10(-6)M. Binding constant is estimated with the Benesi-Hildebrand method and the value 8 × 10(4) indicates a fairly strong interaction between TMC and Cr(3+). Speciation studies have been performed in a fast and environment friendly way using least sample volume, less hazardous chemicals and solvents. Cr(3+) assisted restricted rotation around the imine bond and inhibited photo-induced electron transfer from the N,S-donor sites to the coumarin unit are responsible for fluorescence enhancement. TMC is capable to detect intracellular Cr(3+) in living cells.

Nickel(II)-induced excimer formation of a naphthalene-based fluorescent probe for living cell imaging.

Ni(2+)-induced intramolecular excimer formation of a naphthalene-based novel fluorescent probe, 1-[(naphthalen-3-yl)methylthio]-2-[(naphthalen-6-yl)methylthio]ethane (L), has been investigated for the first time and nicely demonstrated by excitation spectra, a fluorescence lifetime experiment, and (1)H NMR titration. The addition of Ni(2+) to a solution of L (DMSO:water = 1:1, v/v; λ(em) = 345 nm, λ(ex) = 280 nm) quenched its monomer emission, with subsequent enhancement of the excimer intensity (at 430 nm) with an isoemissive point at 381 nm. The fluorescence lifetime of free L (0.3912 ns) is much lower than that of the nickel(2+) complex (1.1329 ns). L could detect Ni(2+) as low as 1 × 10(-6) M with a fairly strong binding constant, 2.0 × 10(4) M(-1). Ni(2+)-contaminated living cells of plant origin could be imaged using a fluorescence microscope.

Interaction of soft donor sites with a hard metal ion: crystallographically characterized blue emitting fluorescent probe for Al(III) with cell staining studies

A naphthalene based compound, 1-((E)-(2-(2-(phenylthio)ethylthio)phenylimino)methyl)naphthalen-2-ol (L2) has been synthesized and characterized by FTIR, 1H NMR, mass spectra and single crystal X-ray structure analysis. L2 shows a blue shift with a large fluorescence enhancement in the presence of Al3+ which is attributed to a chelation-enhanced fluorescence (CHEF) effect with inhibition of an intramolecular charge transfer (ICT) process and cis/trans isomerization. L2 binds to Al3+ with 2 : 1 stoichiometry (mole ratio) with an association constant (Ka) of 0.15 × 104 M−1/2. The detection limit for Al3+ is 5 × 10−8 M in DMSO/H2O (1 : 2, v/v). L2 can efficiently detect intracellular Al3+ under fluorescence microscope

Antipyrine based arsenate selective fluorescent probe for living cell imaging.

Condensation of salicylaldehyde and 4-aminoantipyrine has yielded a new fluorescent probe (APSAL) capable of detecting intracellular arsenate at the micromolar level for the first time. The structure of the probe has been established by different spectroscopic techniques and confirmed from X-ray crystallography. Common anions, viz., F(-), Cl(-), Br(-), I(-), N(3)(-), NCO(-), NO(2)(-), NO(3)(-), SCN(-), CN(-), CH(3)COO(-), SO(4)(2-), ClO(4)(-), and HPO(4)(2-) do not interfere. The binding constant of APSAL for H(2)AsO(4)(-) has been determined using the Benesi-Hildebrand equation as 8.9 × 10(3) M(-1). Fluorescence quantum yield of APSAL (0.016) increases more than 12 times upon binding arsenate ion.

Thiophene anchored naphthalene derivative: Cr3+ selective turn-on fluorescent probe for living cell imaging

A naphthalene-based thiophene derivative (L) can act as a Cr3+ selective turn-on fluorescence probe in aqueous methanol. The structure of L has been established from different spectroscopic data and confirmed by X-ray crystallography. Under optimum conditions, the fluorescence intensity of L increases linearly from 1.0 × 10−6 to 52 × 10−6 M Cr3+ with a detection limit of 1.5 × 10−7 M. L also exhibits good cell permeability and can detect intracellular Cr3+ in contaminated living cells.

An INHIBIT logic gate from a thiophene derivative using iron and zinc ions as the input: tuning the efficiency on moving from naphthalene to anthracene to pyrene for the green luminescent detection of the intracellular iron.

A pyrene-thiophene conjugate has been used for the efficient detection of intracellular irons through the generation of bright green luminescence. Amongst three different probes being reported, it is observed that the efficiency for the naked eye green luminescent detection of iron increases on moving from naphthalene to anthracene to pyrene. The developed technique may be very useful to monitor iron and zinc supplementation as single micronutrients in living systems through the construction of an INHIBIT logic gate.

Anthracene appended coumarin derivative as a Cr(III) selective turn-on fluorescent probe for living cell imaging: a green approach towards speciation studies

A facile one step reaction between 6-aminocoumarin and anthracene-9-carboxaldehyde has resulted in a novel fluorescent probe, 6-((anthracen-9-yl) methyleneamino)-2H-chromen-2-one (AC) which is capable of selectively detecting intracellular Cr3+ in contaminated living cells under a fluorescence microscope. The binding of AC with Cr3+ is well characterized by different spectroscopic techniques. The binding constant values in CH3CN–water (9 : 1, v/v) and methanol–water (9 : 1, v/v) solutions have been estimated to be 1.1 × 105 and 3.1 × 105 respectively using the Benesi–Hildebrand equation. The detection limit for Cr3+ is 0.5 × 10−6 M. The developed method has been used for speciation studies in a fast and environment friendly way using least amounts of samples, non-hazardous chemicals and solvents.

Cu(II) complex of a new isoindole derivative: structure, catecholase like activity, antimicrobial properties and bio-molecular interactions

An isoindole based Cu(II) complex, [Cu(PICPH)Cl2], was synthesized in situ by reacting copper(II) chloride with a pyridine derived ligand, PICPH. The complex was characterized by spectroscopic techniques while its structure was confirmed by single crystal X-ray diffraction analysis. The complex has a trigonal bipyramid geometry containing both five- and seven-member chelate rings. It shows catecholase-like activity. Interaction of the complex with a bio-relevant antipyrine derivative (ANNAP) was studied using fluorescence spectroscopy. DFT studies unfold the energetics associated with PICPH, [Cu(PICPH)Cl2] and the adduct between [Cu(PICPH)Cl2] and ANNAP. Antimicrobial activities of the compounds were also studied.

2-(2-Pyridyl) benzimidazole-based ternary Mn(II) complex as an arsenate selective turn-on fluorescence probe: ppb level determination and cell imaging studies

2-(2-Pyridyl) benzimidazole based ternary Mn(II) complex (MnPBINCO) is established as an arsenate selective turn-on fluorescence probe in HEPES buffered (0.1 M, methanol/water = 0.5/99.5, v/v, pH 7.4) solution for the first time. MnPBINCO can determine the presence of HAsO42− at concentrations as low as 1 × 10−10 M and efficiently detect intracellular HAsO42− under a fluorescence microscope.

Interaction of water with a benzimidazole derivative: fluorescence and colorimetric recognition of trace level water involving intra-molecular charge transfer process

Benzimidazole‐derived ICT‐based probe, DFPBEN is developed for trace level determination of water. In presence of water, the naked eye color of DFPBEN changes from red to yellow, while it turns to green from red under UV light. Upon addition of water, DFPBEN shows a ratiometric absorbance change in methanol. Copyright