Synthesis of new cyclotriphosphazene derivatives bearing Schiff bases and their thermal and absorbance properties

Recent Developments in Colorimetric and Fluorometric Detection Methods of Trivalent Metal Cations (Al3+, Fe3+ and Cr3+) Using Schiff Base Probes: At a Glance

This review basically concerned with the application of different Schiff bases (SB) based fluorimetric (turn-off and turn-on) and colorimetric chemosensors for the detection of heavy metal cations particularly Al(III), Fe(III), and Cr(III) ions. Chemosensors based on Schiff bases have exhibited outstanding performance in the detection of different metal cations due to their facile and in-expensive synthesis, and their excellent coordination ability with almost all metal cations and stabilize them in different oxidation states. Moreover, Schiff bases have also been used as antifungal, anticancer, analgesic, anti-inflammatory, antibacterial, antiviral, antioxidant, and antimalarial etc. The Schiff base also can be used as an intermediate for the formation of various heterocyclic compounds. In this review, we have focused on the research work performed on the development of chemosensors (colorimetric and fluorometric) for rapid detection of trivalent metal cations particularly Al(III), Fe(III), and Cr(III) ions using Schiff base as a ligand during 2020-2022.

A multifunctional fluorescent probe based on Schiff base with AIE and ESIPT characteristics for effective detections of Pb2+, Ag+ and Fe3

In this work, three Schiff-based fluorescent probes with aggregation-induced emission (AIE) and excited intramolecular proton transfer (ESIPT) characters were synthesized by grafting 2-aminobenzothiazole group onto 4-substituted salicylaldehydes. More important, a rare tri-responsive fluorescent probe (SN-Cl) was developed by purposeful variation of substituents in the molecule. It could selectively identify Pb2+, Ag+ and Fe3+ in different solvent systems or with the help of masking agent and show complete fluorescence enhancement without interference of other ions. Meanwhile, the other two probes (SN-ON and SN-N) could only recognize Pb2+ in DMSO/Tris-HCl buffer (3: 7, v/v, pH = 7.4). According to Job's plot, density functional theory (DFT) calculations and NMR analysis, coordination between SN-Cl and Pb2+/Ag+/Fe3+ was determined. The LOD values for three ions were as low as 0.059 μM, 0.012 μM and 8.92 μM, respectively. Ideally, SN-Cl showed satisfactory performance in real water samples detection and test paper experiments for three ions. Also, SN-Cl could be used as an excellent imaging agent for Fe3+ in HeLa cells. Therefore, SN-Cl has the ability to be a "single fluorescent probe for three targets".

N-substituted benzenesulfonamide compounds: DNA binding properties and molecular docking studies

Benzenesulfonamide-based imine compounds 5-8 were prepared and screened for their binding properties to the FSdsDNA. The structures of synthesized compounds were elucidated by the spectroscopic and analytical methods. Compounds 5-8 were screened for their interactions with the FSdsDNA. Compound 8 showed the highest binding affinity to the FSdsDNA with intrinsic binding constant of 3.10 × 104 M-1. The compounds caused the quenching of the DNA-EB emission indicating displacement of EB (ethidium bromide) from the FSdsDNA. Finally, the binding interactions between the DNA and binder molecules 5-8 were examined by the molecular docking studies. The compounds locate approximately same region of the minor groove of DNA via hydrogen bonding contacts between the sulfonamide oxygen atoms and the DG10/DG16 nucleotides of DNA.Communicated by Ramaswamy H. Sarma.

Crystallization of Nano-Sized Macromolecules by the Example of Hexakis-[4-{(N-Allylimino)methyl}phenoxy]cyclotriphosphazene

The synthesized compound was characterized by ³¹P, ¹³C, and ¹H NMR spectroscopy and MALDI-TOF mass spectroscopy. According to DSC data, the compound was initially crystalline, but the crystal structure was defective. The crystals suitable for X-ray diffraction study were prepared by slow precipitation of the compound from a solution by a vapor of another solvent. A study of the single crystal obtained in this way demonstrated that the phosphazene ring has a flattened chair conformation. It was found that the sphere circumscribed around the compound molecule has a diameter of 2.382 nm.

Tungsten disulfide (WS2)/fluorescein ratiometric fluorescent probe for detection of cefixime residues in milk

In this research work, it has been reported a ratiometric fluorescent sensor based on tungsten disulfide quantum dots (WS₂ QDs) and fluorescein for the determination of Cefixime (CEF). When excited by radiation of 400 nm wavelength the probe illustrates dual emissions centered at 460 nm and 510 nm. CEF quenches the fluorescence (FL) intensity of fluorescein (510 nm), while it doesn't affect the FL emission of WS₂ QDs at 460 nm. The change in the ratio of the two peaks (F₄₆₀/F₅₁₀₎ of the prepared sensor (WS₂ QDs/fluorescein) is linearly proportional to the CEF concentration in the range of 200-2.500 ng/mL with a limit of detection (LOD) of 45 ng/mL. Hence, the proposed probe can be successfully used for CEF quantification in the milk samples.

A Review on Synthesis, Structural, Flame Retardancy and Dielectric Properties of Hexasubstituted Cyclotriphosphazene

Hexachlorocyclotriphosphazene is a ring compound consisting of an alternating phosphorus and nitrogen atom with two chlorine substituents attached to the phosphorus atom. The six chlorine atoms attached to this cyclo compound can be substituted with any different nucleophile that leads to changes in different chemical and physical properties. The major topics that were investigated in this research are the flame retardancy and dielectric properties of cyclotriphosphazene compounds. Cyclotriphosphazene compounds have high potential to act as a flame retardant, and this compound consists of two active elements attributed to its high flame-retardant character. This compound also demonstrated good ability as a flame retardant due to its low toxicity and less smoke produced. In addition, cyclotriphosphazene compounds were also investigated for their dielectric properties. Cyclotriphosphazene has high potential in the electrical field since it has dielectric properties that can be widely studied in the investigation of any potential application. This review presented literature studies focused on recent research development and studies in the field of cyclotriphosphazene that focused on synthesis, structural, flame retardancy, and dielectric properties of hexachlorocyclotriphosphazene compounds.

A “turn-on” small molecule fluorescent sensor for the determination of Al3+ ion in real samples: theoretical calculations, and photophysical and electrochemical properties

The fluorescence sensing properties of a naphthalene-based acetohydrazide (3) were investigated. A highly selective “turn-on” response was obtained towards Al3+ ions, and this was used for real sample analysis and development of paper test strips.

ESIPT on/off switching and crystallization-enhanced emission properties of new design phenol-pyrazole modified cyclotriphosphazenes

Cyclophosphazene-based high-efficiency excited state intramolecular proton transfer (ESIPT) active and inactive molecules were prepared depending on the different bonding patterns of the difunctional phenol-pyrazol reagent.

R. M, Gurusamy Thangavelu SA, Krishnamoorthy A. Tunable yellow–green emitting cyclotriphosphazene appended phenothiazine hydrazone hybrid material: synthesis, characterisation, photophysical and electrochemical studies

A novel tunable yellow–green emitting inorganic–organic luminescent hybrid molecule, CTP-PTZ, an assembly of six units of the PTZ hydrazone Schiff base on the periphery of inorganic heterocycle cyclotriphosphazene, is reported.

Novel paraben derivatives of tetracyclic spermine cyclotriphosphazenes: synthesis, characterization and biosensor based DNA interaction analysis

A new series of paraben-substituted dispiroansa (tetracyclic) spermine derivatives of cyclotriphosphazenes likely to be biologically active were synthesized for the first time and their effects on DNA were studied.