Synthesis of new anthracene-substituted calix[4]triazacrown-5 as highly sensitive fluorescent chemosensor and extractant against hazardous dichromate anion

Novel Anthracene-Appended Calix[4]triazacrown-5 as an Effective Fluorescence Probe for Co2+ and Hazardous Cr2O7 2- Ions

A new calix[4]triazacrown-5-derived fluorescence chemosensor (AntUr-AzClx) at cone conformation was synthesized to afford an effective fluorescent probe, which enables an enhancement in the fluorescence intensity specifically in the presence of Co2+ metal ions as well as a turnoff response for hazardous dichromate anions. 1H-NMR, 13C-NMR, ESI-MS, and elemental analysis techniques were used to characterize the structure of the anthracene-appended calix[4]triazacrown-5 (AntUr-AzClx). The metal ion-binding ability of AntUr-AzClx was evaluated against Co2+, Ba2+, Ni2+, Pb2+, and Zn2+ ions. On the basis of various metal ion recognition phenomena, AntUr-AzClx exhibited outstanding selectivity for only the Co2+ ion among other metal ions. Also, the calix[4]triazacrown-5-derived fluorescence chemosensor showed high sensitivity towards the Co2+ ion with a very low limit of detection (LOD) 0.142 μmol L-1. In addition, anion binding abilities of AntUr-AzClx against various anions such Cr2O7 2-, HCO3 -, CO3 2-, NO3 -, SO3 2-, SO4 2-, N3 -, F-, and I- demonstrated that AntUr-AzClx enables selective and highly sensitive detection of the Cr2O7 2- anion with an excellent LOD of 4.182 nmol L-1 in DMF/PBS (1/1, v/v; pH: 7.05). Furthermore, the calix[4]triazacrown-5-derived fluorescence chemosensor displayed a significant sensing behavior to detect the presence of dichromate anions even in real samples.

Controlled Primary Amine-Enriched SG-Bonded Papain Surface: Synthesis, Characterization, and Extraction of Protonated Dichromate

The single-step synthesis of nitro-derivatized SG using dimethyldichlorosilane in an aprotic solvent dichloromethane at 300 K is efficient and straightforward. Reduction and diazotization effectively functionalize the material for enzyme coupling at the O-carbon of the enzyme's tyrosine. The high extraction efficiency of protonated dichromate ions with a breakthrough capacity of 480 μmol·g-1 is notable. Eco-friendly elution using distilled water achieves a significant enrichment factor of 23.2. Excellent reusability (up to 900 cycles) and stable sorption efficiency (ζ ≥ 0.9) highlight the material's potential for practical applications and future research.

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.

Novel An Efficient Fluorescent Probe Based on Calix[4]triazacrown-5 With Naphthalimide Group for Co2+, Cd2+ and Dopamine Detection

A novel naphthalimide-substituted calix[4]triazacrown-5 (Nap-Calix) at cone conformation was designed and synthesized to employ as a fluorescent probe, which enables the simultaneously detection of Co2+ and Cd2+ metal ions as well as dopamine (DA). 1H-NMR, 13C-NMR, ESI-MS and elemental analysis techniques were carried out to characterize its structure. Cation binding property of Nap-Calix against various metal ions such as Ba2+, Co2+, Ni2+, Pb2+, Zn2+, and Cd2+ exhibited that the sensor selectively binds to Co2+ and Cd2+ metal ions with a remarkable affinity. Introduction of Co2+ and Cd2+ metal ions to a solution of Nap-Calix in DMF/water (1:1, v/v) resulted with a new emission band at 370 nm when excited at 283 nm. In addition, the fluorescence sensing affinity of the probe Nap-Calix against a catecholamine neurotransmitter (dopamine) was investigated in a wide range of concentration of DA (0-0.1 mmol L-1) in 50% DMF/PBS (pH = 5.0). The fluorescence intensity of Nap-Calix, with excitation/emission peaks at 283/327 nm, is highly enhanced by DA. It was also observed that Nap-Calix exhibits excellent fluorescence behavior towards DA with a very low detection limit as 0.21 µmol L-1.

A highly selective and sensitive fluorescence probe for dopamine determination based on a bisquinoline-substituted calix[4]arene carboxylic acid derivative

Dopamine (DA) at normal levels in the human body exhibits a high potential for maintaining a proper neuron network. However, their abnormalities in humans can bring out aggressive disorders such as Schizophrenia, hypertension, Tourette's syndrome, Alzheimer's disease, bipolar depression, Parkinson's disease, drug addiction and attention-deficit hyperactivity diseases. Hence, in this study, a bis-quinoline-substituted calix[4] arene carboxylic acid derivative (Quin-Calix-CO2H) at cone conformation was developed as an effective fluorescent sensor for the detection of a catecholamine neurotransmitter (dopamine). The structure of Quin-Calix-CO2H was confirmed using 1H-NMR, 13C-NMR, ESI-MS and elemental analysis techniques. The calixarene-based fluorescent sensor (Quin-Calix-CO2H) has shown fluorescence emission at 404 nm under the excitation of 270 nm. Further, biomolecules binding property of Quin-Calix-CO2H against various biomolecules such as L-cysteine (L-Cys), α-D-glucose (D-Glu), (+)-sodium-L-ascorbate (SAA), urea (UR), L-alanine (L-Ala) and dopamine (DA) exhibited that the fluorescent sensor enables selectively and sensitively detection for DA with a remarkable affinity. The probe Quin-Calix-CO2H has shown fluorescence quenching towards DA concentration ranging from 0 to 4.0 µM with a very low limit of detection (LOD) of 88.5 nmol L-1. In addition, the binding constant and stoichiometry as well as the mechanism of quenching have been also determined from the fluorescence data.Communicated by Ramaswamy H. Sarma.

A cellulose-based material as a fluorescent sensor for Cr(VI) detection and investigation of antimicrobial properties of its encapsulated form in two different MOFs

It is crucial to detect toxic chromium ions quickly, reliably, sensitively and at low concentrations. In recent years, fluorescence-based methods have been developed for the rapid detection and determination of toxic ions such as chromium. In present work, we focused on the development of a cellulose-based fluorescent probe (Cel-Nap) for the determination of Cr(VI). The fluorescent probe bearing the 1,8-naphthalimide group displayed a low LOD of 1.07 μM for Cr(VI) in the working range of 0.33 × 10^-5-3.22 × 10^-5 M. The fluorescence and antibacterial properties of UiO-66-Cel-Nap and ZIF-8-Cel-Nap materials prepared by encapsulating Cel-Nap with 2 different MOF types (UiO-66 and ZIF-8) were investigated. While it was found that ZIF-8-based materials had better antimicrobial properties compared to those of UiO-66, it was determined that materials containing Ag⁺ were more effective against microbial than those containing AgNPs. It was found that the most effective material was ZIF-8-Cel-Nap-Ag⁺ and it had a significant antibacterial effect against E. coli at a MIC value of 0.0024 mg/mL.