A new azo compound, 1-(2-pyridylazo)-2-naphthol, has been prepared and characterized. The synthesized compound shows a very high affinity for aluminium. The complexation reaction of aluminium has been explored by Colorimetry, FT-IR, 1 H NMR, HRMS and fluorescence spectroscopy. The detection limit has been found to be 1.81 × 10 −8  M estimated by the titration method. The turn-on fluorescence behaviour of aluminium interaction with ligand has been found to be so fast (

A highly selective colorimetric and turn-on fluorescent chemosensor based on 1-(2-pyridylazo)-2-naphthol for the detection of aluminium(III) ions

A series of rhodamine derivatives L1–L3 have been prepared and characterized by IR, 1H-NMR, 13C-NMR and ESI-MS. These compounds exhibited selective and sensitive “turn-on” fluorescent and colorimetric responses to Al3+ in methanol. Upon the addition of Al(III), the spiro ring was opened and a metal-probe complex was formed in a 1:1 stoichiometry, as was further confirmed by ESI-MS spectroscopy. The chemo-dosimeters L1–L3 exhibited good binding constants and low detection limits towards Al(III). We also successfully demonstrate the reversibility of the metal to ligand complexation (opened ring to spirolactam ring).

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Highly Sensitive and Selective Colorimetric and Off-On Fluorescent Reversible Chemosensors for Al3+ Based on the Rhodamine Fluorophore

1-((quinolin-3-ylimino)methyl)naphthalen-2-ol (HL) has been synthesized by one step Schiff-base condensation reaction between 2-hydroxy-naphthaldehyde and 3-aminoquinoline in 1:1 ratio in acetonitrile and characterized by elemental analysis and different spectroscopic techniques. Emission spectrum of HL shows peak at 412 nm with high intensity in methanol when it is excited at 350 nm. In the presence of Al3+ ion, emission intensity of the Schiff-base at 412 nm decreases and a new peak at 464 nm emerges indicating HL as a ratiometric chemosensor for the Al3+ ion. Other metal ions are not able to change the fluorescence intensity or peak position significantly. Job’s plot analysis indicates 1:1 binding with the formation of complex (complex 1) which is supported by mass spectral measurement. Emission intensity of complex 1 at 464 nm (excitation at 350 nm) decreases with the gradual addition of F− ion with the concomitant development of a peak at 412 nm with fast increasing intensity. Small LOD value of HL suggests it is sensitive towards Al3+. Based on change in fluorescence intensity of HL in the presence of Al3+ and F− ions at 412 and 464 nm, INHIBIT and IMPLICATION molecular logic gates have been constructed and interpreted.

A ratiometric chemosensor for Al3+ based on naphthalene-quinoline conjugate with the resultant complex as secondary sensor for F−: Interpretation of molecular logic gates

In this article, we tried to redefine the unexplored potential of a benzothiazole type of Schiff-base (OM), which was identified as an AIE-active molecule that exhibits excited-state intramolecular proton transfer (ESIPT). Interestingly, this compound shows ultra-sensitivity and selectivity in the detection of Al(III) (12 pM; 456 ppt). The OM was capable of pH sensing and was also tested for internalization in cancerous cells for intracellular imaging. Computational modeling was performed and the results were in good agreement with the experimental UV-Vis spectrum and the energy gap obtained in basic and acidic media.

Exploring the hidden potential of a benzothiazole-based Schiff-base exhibiting AIE and ESIPT and its activity in pH sensing, intracellular imaging and ultrasensitive & selective detection of aluminium (Al3+).

Cost-effective and highly sensitive biocompatible probes for the detection of Al3+ have tremendously important practical applications. Herein, we report for the first time, the hydrazinopyrimidine based Al3+ chemosensor L (1-[(4,6-dimethyl-pyrimidin-2-yl)-hydrazonomethyl]-naphthalen-2-ol) prepared by the condensation of 2-hydroxy-1-naphthaldehyde and 4,6-dimethyl-2-hydrazino-pyrimidine. Our as-synthesized chemosensor L (Φ = 0.0066) shows ∼15 fold fluorescence enhancement in the presence of Al3+ (Φ = 0.0955, Ka = 1.9 × 104 M−1) via chelation enhanced fluorescence (CHEF), excited state intramolecular proton transfer (ESIPT), and inhibited photo-induced electron transfer (PET) phenomena. The limit of detection (LOD) and limit of quantification (LOQ) were estimated to be 2.78 μM and 9.27 μM, respectively. Furthermore, for the first time, a hydrazino pyrimidine based ‘INHIBIT’ molecular logic gate for Al3+ was successfully developed using the fluorescence properties of L. The experimental sensing mechanisms of L for Al3+ were corroborated by theoretical calculations. Biocompatibility and good water-solubility properties of a pyrimidine moiety of L inspired us to investigate Al3+ imaging in human embryonic kidney cell lines, HEK293, and the results for practical applications are highly promising.

Hydrazinopyrimidine derived novel Al3+ chemosensor: molecular logic gate and biological applications

5G and forthcoming 6G communication systems require dielectric ceramics with low relative permittivity (εr) and near-zero temperature coefficient of resonant frequency (τf) for the lower part of the microwave (MW) band and at sub-Terahertz. Mg2Al4Si5O18 (MAS) ceramics are promising candidates due to their low εr (~ 6) and high-quality factor (Q×f > 40,000 GHz) but have a large τf. In this study, 5.5 wt% TiO2 (MAS-T5.5) was used to adjust τf of MAS to −2.8 ppm/℃ whilst retaining low εr (5.24) and good Q×f (33,400 GHz), properties consistent with those obtained by infrared reflectance. A demonstrator microstrip patch antenna with gain 4.92 dBi and 76.3% efficiency was fabricated from MAS-T5.5. 

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Low permittivity cordierite-based microwave dielectric ceramics for 5G/6G telecommunications

Research of a highly selective fluorescent chemosensor for aluminum(III) ions based on photoinduced electron transfer

Three lanthanide complexes with the formula [Ln(Hbtca)(3)(4,4'-bpy)(H2O)(2)](n)center dot nH(2)O [Ln = Eu (1), Gd (2), Tb (3)] (4,4'-bpy = 4,4'-bipyridine; H(2)btca = benzotriazole-5-carboxylic acid) were synthesized and characterized. Single-crystal X-ray diffraction analysis shows that complexes 1-3 possess 1D chain structures. There are O-H center dot center dot center dot N, O-H center dot center dot center dot O, and N-H center dot center dot center dot N hydrogen bonds, which result in the formation of 3D supramolecular networks. When excited at 360 nm, complexes 1 and 3 give characteristic emissions of Eu-III and Tb-III ions, respectively, whereas in the mixed Eu/Tb complex, Eu-III emissions are strengthened and Tb-III emissions are quenched, which indicates that energy may be transferred from Tb-III to Eu-III ions.

Di Zhou

Papers

Low permittivity cordierite-based microwave dielectric ceramics for 5G/6G telecommunications

Research of a highly selective fluorescent chemosensor for aluminum(III) ions based on photoinduced electron transfer

Syntheses, Structures, and Fluorescent Properties of Lanthanide Complexes Based on the Ligand Benzotriazole‐5‐carboxylic Acid

Syntheses, structures and photoluminescence properties of iridium (III) complexes based on a salen ligand

Di Zhou

Papers

Low permittivity cordierite-based microwave dielectric ceramics for 5G/6G telecommunications

Research of a highly selective fluorescent chemosensor for aluminum(III) ions based on photoinduced electron transfer

Syntheses, Structures, and Fluorescent Properties of ­Lanthanide Complexes Based on the Ligand Benzotriazole‐5‐carboxylic Acid

Syntheses, structures and photoluminescence properties of iridium (III) complexes based on a salen ligand

Syntheses, Structures, and Fluorescent Properties of Lanthanide Complexes Based on the Ligand Benzotriazole‐5‐carboxylic Acid