The Fluorescence Sensing Capability of 1,4-dihydroxyanthraquinone Towards Metal Ions and Imaging Cells.

Fluorescence and colorimetric sensors have gained significant traction in diverse scientific domains, including environmental, agricultural, and pharmaceutical chemistry. This article comprehensively surveys recent advancements in developing sensors employing 1,4-dihydroxyanthraquinone(1,4-DHAQ). The study delves into the unique properties of 1,4-dihydroxyanthraquinone(1,4-DHAQ) as a sensor, focusing on its capacity to detect Cu2+ ions and elucidating its fluorescence quenching mechanisms. Furthermore, the interaction of dihydroxyanthraquinone with Ga(III), Al(III), and In(III) ions is explored under both aqueous and non-aqueous conditions, leading to the formation of distinctive fluorescent species. The investigation extends to factors influencing ligand behavior, including time dependency, temperature, solvent type, counterions, and pH levels. These key parameters are systematically analyzed to understand sensor performance better. In conclusion, the article investigates the utility of the 1,4-dihydroxyanthraquinone-Zn2+ probe as a versatile sensing platform for phosphate anions, particularly in live cell imaging. The findings contribute to the evolving landscape of sensor technologies, offering insights into the diverse applications and potential advancements in this burgeoning field.

Effects of Metal Ions and Substituents on HOMO-LUMO Gap Evident from UV-Visible and Fluorescence Spectra of Anthracene Derivatives.

Controlled intake of complex metal cations and anions in the human body and other biological systems is essential for the health and well-being of the environment. Anthracene and anthracene derivatives are the most widely used sensors for this purpose. Because of their convenience, better detection and results are preferred over colorimetric sensors, which offer better color detection by the naked eye. This review article will present different designs of chemosensors using fluorescence and UV-visible spectroscopy to determine different ions. Density functional theory and Austin model 1 are widely used for theoretical and computational studies of the energy levels of molecules. The Indo/Cis method is used to calculate the geometries of anthracene oligomers. A novel anthracene-based fluorescent probe containing the benzothiazole group BFA was highly sensitive and selective toward trivalent cations (Cr3+ and Fe3+). This sensor is not sensitive to other ions, including Aluminum trivalent ions. (N- ((anthracen-9-yl) methyl)-N-(pyridin-2-yl) pyridin-2-amine) has been designed to detect zinc and copper. Click chemistry using photodimerization can be used to form cellulose nanoparticles. TEMPO-mediated hypohalite oxidation converts hydroxyl groups to carboxylic groups. Amide linkage formation between amine and carboxylic acid was followed by the installation of an alkyne group. Copper (I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) was used to produce highly photoresponsive and fluorescent cellulose nanoparticles by using coumarin, anthracene, and generated nanomaterials. The effects of naphthalene and phenanthrene on the spectra of anthracene were determined in a dilute solution. Temperature and solvent effects introduce different changes in fluorescence, emission, and absorption bands, leading to some changes in the configuration of anthracene. The solvent and temperature effects on variations of emission maxima of exciplex anthracene-diethylaniline (DEA) are also discussed.

Investigating the Use of Coumarin Derivatives as Lasers.

A benzene ring and a lactone ring combine to form the chemical coumarin. Dye lasers have made significant advances in laser technology. The coumarin molecule itself is a non-fluorescent but it displays high fluorescence when electron-denoting substituents such as sulfonamide, benzopyrone, amine, benzothiazole, hydroxyl, methoxy are substituted at various positions. Substituted coumarin possesses the highest energy properties, photostability, and alteration in electron mobility, and therefore could be effectively used as dye lasers. These are considered some of the best fluorophores due to their outstanding photophysical and photochemical properties, which include high fluorescence quantum yields, great photostability, good functionality, and a wide spectrum range. Various inorganic materials are used in classic laser technology to generate the necessary emission. Inorganic lasers come in various types and can emit light in the electromagnetic spectrum's ultraviolet, visible, or infrared parts. Inorganic lasers have certain limitations, which is why coumarin lasers are becoming increasingly popular due to their many advantages. Compared to inorganic lasers, dye lasers offer far better tunability and cover the entire visible and near-infrared range. They only emit at very few specific wavelengths and in extremely narrow bands. The property is therefore presented in this review.

Effect of Substituents on Solubility, Medicinal, Absorption, Emission and Cationic/Anionic Detection Properties of Anthraquinone Derivatives.

Anthraquinones constitute an important class of compounds with wide applications. The solubility of derivatives at 298.15 K was discussed in ethanol-water solution and at atmospheric pressure, the solubility of 1-amino-4-hydroxy-9,10-anthraquinone (AHAQ) in binary solvents (ethanol-water combinations) was determined. Colour strength and fastening properties depend upon the kind and position of a hydrophobic group connected to the phenoxy ring of Anthraquinone moiety. There is a continuing interest in the creation of novel anthraquinone derivatives with biological activities since they have demonstrated potential for treating multiple sclerosis. For this purpose, by utilizing voltammetric and absorption studies, interactions of various derivatives with calf thymus DNA (ct-DNA) and the cationic surfactant cetyltrimethylammoniumbromide (CTAB) were examined. Here prominent Hydrophobic interaction and electron transfer resulting in binding to CTAB micelles were observed. The polarity index of the media was assessed and associated with the electrochemical parameters. The medicinal behaviour of Anthraquinone derivatives was a result of electron transfer reactions with DNA. UV-Visible and fluorescence properties were due to the transitions between n* and π* orbitals. Large absorption band with low dichroic ratio was characteristic of various derivatives of Anthraquinone. Presence of -NH group proves various derivatives remarkable calorimetric and anionic sensors.

Effect of Chloride, Sulfate, and Ferrate Salts on Electronic Energy Levels of Anthracene Proving it a Potential Candidate as an ON and ON-OFF UV-Vis Sensor.

Anthracene molecule possesses remarkable optical activity and till today this molecule is of special interest of scientists. Present study is focused on the study of effects of Chloride, Sulfate, Nitrate and Ferrate salts on absorption and emission spectra of targeted fluorophore in carbontetrachloride, chloroform, dichloromethane and methanol. Prominent solvatochromic effects shows dependence of HOMO-LUMO orbitals on solvent polarity. Anthracene molecules exhibits changes in absorption and emission spectra, and show both ON and ON-OFF behavior on addition of said ions. Based on experimental results it was concluded that fluorophore molecule could be used more effectively as UV-Visible (UV-V) sensors in comparison to the emission sensor.

Naphthalene and its Derivatives: Efficient Fluorescence Probes for Detecting and Imaging Purposes.

Naphthalene, white crystalline solid having polycyclic aromatic hydrocarbon with characteristic mothball order is naturally present in crucial oils of various plants. Naphthalene derivatives are extensive drug resources and are use as wetting agents, surfactants and as insecticides. These derivatives exhibit unique photo physical and chemical properties. These characteristics make them the most studied group of organic compounds. Naphthalene dyes have rigid plane and large π-electron conjugation. Therefor they have high quantum yield and excellent photostability. Naphthalene based fluorescence probes due to hydrophobic nature exhibit excellent sensing and selectivity properties towards anions and cations and also used as a part of target biomolecules. In conjugated probe system, introducing naphthalene moiety caused improvement in photo-stability. Therefore among various conjugated framework, naphthalene derivatives are considered excellent candidate for the construction of organic electronic appliances. These derivatives are useful for a variety of applications owing to their strong fluorescence, electroactivity and photostability. This article is based upon investigation of photophysical properties of naphthalene derivatives and fluorescence detecting probe of naphthalene. For photophysical properties the techniques under investigation are UV visible spectroscopy and fluorescence spectroscopy. Concentration dependent spectra and solvatochromic shifts on UV visible spectra are also part of discussion.

Study of Interactions Between 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine and Human DNA by Theoretical, Spectroscopic and Viscometric measurements.

From the last few years mode of interactions between drugs and DNA is an attractive research area as it bridges chemistry, molecular biology and medicinal science. Interactions between small heterocyclic molecules and human DNA is a noteworthy feature in pharmacology for investigation of drugs mechanism and designing of more effective and target specific drugs with fewer side effects. The present research work focuses on the theoretical investigations of 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine (SASA) by using Gaussian (16 W) software to predict optimized geometry, HOMO-LUMO gap, bond length, bond angle, dihedral angle, electronic and vibrational spectra. Possible reaction site observed in SASA was C7, C9 and C18 as these atoms show maximum charge density. Later the interactions of SASA with human DNA was explored spectroscopic investigations and viscometric investigations at physiological buffers of pH of 4.7 (stomach pH) and 7.4 (blood pH) respectively. Maximum absorbance between SASA-DNA complex was observed in buffer solution of pH 3.4 at wavelength of 370 nm, whereas at 7.4 has maximim absorbance between. Spectroscopic results reflects the bathochromic and hyperchromic shift succeeding the addition of human DNA. During viscosity measurement, intercalation and electrostatic mode of interaction were detected at low and high concentration of drug in solution respectively. Increase in the value of rate constant was observed with the increase in concentration of drug. Larger values of rate constant were observed at pH 7.4 in comparison to pH 3.5. Rate constant, thermodynamic parameters and viscometric analysis prefers the intake of SASA via blood.

Computational Studies Followed by Effect of Solvent Polarity and Salts on HOMO-LUMO Gap of 7-Hydroxy Coumarine Notabally Reflected by Absorption and Emission Spectra.

7-Hydroxycoumarin's FT-IR solid phase spectra were observed at 4000-400 cm-1. The spectra were analyzed in aspects of significant approaches. DFT was used to optimize the structure of the compound and its structural properties. The molecular properties were also determined by the HF/3-21G level. The bond lengths and bond angles were obtained by the computational study of the optimized geometry. The vibrational frequencies were determined in all these approaches, which were then matched to experimental frequencies, yielding an excellent agreement between measured and estimated frequency ranges. The UV-visible spectrum of 7HC was obtained and the electronic characteristics HOMO and LUMO energies were monitored by the time-dependent TD-DFT method. The spectral behavior of 7-Hydroxycoumarin was studied using fluorescence spectroscopy in a wide range of polar and non-polar solvents. Solvatochromic effect was observed in both the fluorescence and absorption spectra. The structural properties, energies, IR intensities, absorption wavelengths, and harmonic vibrational frequencies were compared with the obtainable experimental information of the molecule.

Excited State Complexes of Coumarin Derivatives.

Furocoumarins are the useful derivatives of coumarin, and they act as skin photosensitizing material due to their exciting exciplex states. Dendrimers also form exciplexes when they contain coumarin as core and used for light harvesting. A number of ingredients in human nutrition contain coumarins. The apiaceae family is the most common example of this class that contains carrots, celery and parsley etc. Rutaceae family is also an important food source that contains coumarins and provides citrus food. Besides fruits and vegetables, beverages like coffee, wine, black and green tea also incorporates coumarin derivatives. Few coumarin dyes show absorption and one emission peak but it can show a double amplified spontaneous emission band due to the generation of super exciplexes in coumarins. Exciplex formation of different coumarin derivatives including 7-methoxy coumarin, 7-hydroxy coumarin show wide application in synthesis of various other derivatives and they can be used as dye due to their prominent fluorescence properties. Exciplexes and excimers of coumarin are widely used in lasers. Both singlet and triplet state exciplexes are considered. Thus a comprehensive review of excited state complexes of coumarin derivatives is discussed here with emphases on the interaction and overlap of the energy levels.

Effect of pH on Fluorescence Spectra of Coumarin Derivatives.

Colourless crystalline solid coumarin with a bitter taste and sweet vanilla-like odor mostly acts as chemical protection against predators in plants. Anticoagulants (blood thinners), anti-fungicidal, anti-tumor and anti-inflammatory properties of coumarin are all used to treat skin diseases. Because of internal charge transfer (ICT), coumarin molecules displayed a solvatochromic effect in various solvents of varying polarity. The emission wavelength dependent fluorescence intensity was also affected by pH.

Citric Acid Enhances Plant Growth, Photosynthesis, and Phytoextraction of Lead by Alleviating the Oxidative Stress in Castor Beans.

Lead (Pb) toxicity has a great impact in terms of toxicity towards living organisms as it severely affects crop growth, yield, and food security; thus, warranting appropriate measures for the remediation of Pb polluted soils. Phytoextraction of heavy metals (HMs) using tolerant plants along with organic chelators has gained global attention. Thus, this study examines the possible influence of citric acid (CA) on unveiling the potential phytoextraction of Pb by using castor beans. For this purpose, different levels of Pb (0, 300, 600 mg kg-1 of soil) and CA (0, 2.5, and 5 mM) were supplied alone and in all possible combinations. The results indicate that elevated levels of Pb (especially 600 mg kg-1 soil) induce oxidative stress, including hydrogen peroxide (H2O2) and malanodialdehyde (MDA) production in plants. The Pb stress reduces the photosynthetic traits (chlorophyll and gas exchange parameters) in the tissues of plants (leaves and roots), which ultimately lead to a reduction in growth as well as biomass. Enzyme activities such as guaiacol peroxidase, superoxide dismutase, ascorbate peroxidase, and catalase are also linearly increased in a dose-dependent manner under Pb stress. The exogenous application of CA reduced the Pb toxicity in plants by improving photosynthesis and, ultimately, plant growth. The upsurge in antioxidants against oxidative stress shows the potential of CA-treated castor beans plants to counteract stress injuries by lowering H2O2 and MDA levels. From the results of this study, it can be concluded that CA treatments play a promising role in increasing the uptake of Pb and reducing its phytotoxicity. These outcomes recommend that CA application could be an effective approach for the phytoextraction of Pb from polluted soils by growing castor beans.

Enzymatic degradation study of 111In-labeled minigastrin peptides using cathepsin B enzyme and AR42J cancer cell line for the development of neuroendocrine tumor imaging radiopharmaceuticals.

Neuroendocrine tumors (NET) are the rare tumors which often impose graveyard threat. These tumors are characterized by the over expression of various G-protein coupled receptors including cholecystokinin (CCK) receptors-1 and 2 (A or B). Minigastrin peptides are being investigated for theranostic purposes of CCK-2 receptor positive NET. The minigastrin analogue (APHO70) was modified by engineering enzyme susceptible tetrapeptide sequence into APHO70 peptide to reduce the random degradation by lysosome enzymes which pave the way to random trafficking in patient's body and dipeptide addition at c-terminus. All the four modified minigastrin peptides (MG-CL1-4) were investigated for lysosome cathepsin B (catB) enzyme susceptibility and fate into AR42J cancer cell line. The indium-111 labeled MG-CL1-4 peptides were also studied for target (tumor) and non-target saccumulation by using tumor induced mice. The RP-HPLC analysis result showed nonspecific cleavage of standard 111In-APH070 and 111In-MGCL1 while specific cleavage was noted in case of 111In-MGCL (2-4). The effect of specific and non-specific cleavage on biodistribution in tumor induced nude mice model indicates the promising accumulation of 111In-MGCL2, 111In-MGCL3, and 111In-MGCL4 radiotracers while 111In-MGCL1 showed less accumulation. 111In-MGCL2 and 111In-MGCL3 showed highest target-to-kidney ratio (T/K) i.e. 1.71 and 1.72, respectively whereas standard compound showed T/K 1.13. In conclusion, the two indium-111 labeled analogues i.e. 111In-MGCL2 and 111In-MGCL3 showed promising sensitivity for tumor andcould be tested for further investigation to reach pre-clinical studies.

Evaluation of 99mTc-sulfadiazine as Bacillus microorganisms infection imaging agent using animal model.

Bacterial infection is one of the vital sources of morbidity and mortality. The development of single photon emission computed tomography (SPECT) radiotracer agents using antibiotics, for targeting in-vivo bacteria, helps in antibiotic dose calibration, targeted infection therapy and reduction in mortality rate. The aim of this study was to appraised 99mTc-labeling sulfadiazine as a radiopharmaceutical for bacillus infections imaging. Radiolabeling of sulfadiazine with technetium-99m was carried out by subsequent addition of 1.5 mL aqueous solution of sulfadiazine (1mg/mL), 120µg stannous tartrate, gentistic acid as stabilizing agent and 185 MBq normal saline solution of 99mTcO4-1 (pertechnetate) at pH = 5. The reaction mixture was incubated for 40 min at room temperature with light stirring. The quality control analysis (ITLC-SG and paper chromatography analysis) revealed ~ 98% labeling yield. Biodistribution and scintigraphic study was carried using bacillus bacterial infection induced New Zealand white rabbits. Due to the ease of 99mTc-sulfadiazine conjugation method, high labeling efficiency, shelf stability (>95% up to 6h), blood serum stability (~90% up to 6h) and high uptake in the infected muscle (T/NT =2.21 at 1H), 99mTc-SDZ could be used as radiopharmaceutical of choice for further pre-clinical and clinical studies.

Spectral and thermodynamic properties for the exciplexes of N-alkyl carbazoles with dicyanobenzenes in THF.

The exciplex emission spectra of N-ethylcarbazole with 1,2-dicyanobenzene (NEC/1,2-DCB), N-methylcarbazole with 1,2-dicyanobenzene (NMC/1,2-DCB), 1,3-dicyanobenzene (NMC/1,3-DCB), and 1,4-dicyanobenzene (NMC/1,4-DCB) are studied in tetrahydrofuran (THF) for the temperature range starting from 253 K to 334 K. Thermochromic shifts along with the spectral properties including change in peak intensities and the ratio of exciplex peak intensity to fluorophore peak intensity are studied. Effect of temperature on the energy of zero-zero transitions hνo('), Huang-Rhys factor (S), Gauss broadening of vibronic level (σ) and the dominant high-frequency vibration (hνν) are also part of investigation. Enthalpy of exciplex formation (ΔH(EX)(∗)) calculated by the model proposed by A. Weller and the Gibb's energy of electron transfer (ΔG(et)(∗)) for all exciplex systems are also discussed in the present paper. All the exciplexes under study were observed to be dipolar in nature. The exciplex of the N-methylcarbazole/1,4-dicyanobenzene was found to be the most stable and the N-methylcarbazole/1,3-dicyanobenzene was the weakest exciplex system.

Absorption and fluorescence emission attributes of a fluorescent dye: 2,3,5,6-tetracyano-p-hydroquinone.

Four cyano groups have been substituted on the aromatic ring of p-hydroquinone (2,3,5,6-tetracyanohydroquinone) in order to study the enhanced photoacidity of this molecule. The acid-base equilibria have been studied using absorption (for ground state pKa) and fluorescence (excited state pKa) spectra. Three distinct species (neutral, anionic and dianionic forms) were observed in the ground state and only two species (anionic and dianionic forms) were found in the excited state when studied at different pH/Ho in water. Absorption and emission characteristics were studied in various organic solvents, including protic and aprotic solvents. Deprotonation was also investigated using binary mixtures. It has been revealed that absorption and emission spectra are considerably changed with change in media. Proton transfer to the solvent has been observed in various solvents.