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In recent developments, graphene quantum dots (GQDs) have emerged as valuable tools for imaging and biosensing. Various modifications on the GQDs with any desired functionality and attachment of organic molecules and/or nanostructures allow tuning their photophysical properties as well as charge transfer dynamics for bioimaging applications. This study focuses on synthesizing and characterizing of polyethyleneimine‐functionalized nitrogen‐doped GQDs (NC1), Schiff base‐ functionalized nitrogen‐doped GQDs (NC2), and silver nanocomposites of these Schiff base‐functionalized nitrogen‐doped GQDs (NC3). We explore their absorption and emission properties to understand their interactions in the ground state. Furthermore, ultrafast transient absorption spectroscopy measurements reveal that the presence of NC3 shortens the excited state lifetime of NC1 due to charge transfer, resulting in reduced fluorescence intensity. Both experimental and DFT results suggest the potential of NC3 for bioimaging and sensing applications, making them promising candidates for phototheranostic purposes. [ABSTRACT FROM AUTHOR]

The new cationic ruthenium(II) complex (2) was synthesized via the reaction of N,N′-[1,1′-(pyridine-2,6-diyl)bis(ethan-1-yl-1-ylidene)]bis(2-ethyl-6-methylaniline) and [RuCl2(p-cymene)]2, and it was fully characterized using NMR, FT-IR, single-crystal X-ray diffraction, ESI-MS, UV-vis, CV and thermal analysis methods; theoretical computational characterizations and geometric parameters for 2 were also carried out via quantum chemical calculations using the density functional theory (DFT) method. In addition, the synthesized Ru(II) complex (2) was immobilized on fabricated RGO-TiO2@FTO to evaluate its non-enzymatic biosensing properties, and the sensing properties of the resulting Ru(II)-RGO-TiO2@FTO electrode were recorded. As a glucose-sensing model, at an applied potential of +0.34 V, the Ru(II)-RGO-TiO2@FTO electrode presented a moderately good sensitivity of 62.69 μA mM−1 cm−1. Various modifications of Ru(II)-RGO-TiO2@FTO-type electrodes, such as the metal complex, and material types and ratios, will enable the design of future biosensor devices with improved performance. [ABSTRACT FROM AUTHOR]

A new fluorescence probe (L) selectively detecting Al3+ ions was synthesized via the condensation reaction, and characterized using UV–Vis, FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. The limit of detection for Al3+ ions of this synthesized probe was found to be 9.29 × 10–7 M, while the Ka constant value was determined to be 1.64 × 104 M−1. The stoichiometric binding ratio of L-Al3+ was found to be 2:1 using the Job's plot method, and this ratio was also confirmed by 1H-NMR titration and mass spectrometry. The recyclability of the chemosensor was found by the fluorescence method through the addition of EDTA to the L-Al3+ solution. The obtained data showed that the carbazole-based Schiff base acted as an ideal chemosensor for Al3+. Carbazole-based Schiff base as a fluorescent sensor for detection of Al3+ was synthesized and characterized. The association constant (Ka) was calculated to be 1.64 × 104 M−1 and the limit of detection (LOD) value was determined to be 9.29 × 10–7 M. It was determined that th Schiff base was bound to Al3+ ions in 2:1 stoichiometric ratio. In the presence of other competitive metal cations, the selectivity of sensor L to Al3+ was not significantly affected. [ABSTRACT FROM AUTHOR]

The condensation reactions of partly substituted spiro and ansa phenoxycyclotriphosphazenes 1 and 2 with tert-butylamine produce disubstituted geminal-bis(tert-butylamino)phenoxycyclotriphosphazene derivatives (3 and 4). The structures of these compounds were characterized by elemental analysis, and IR, ¹H-, 13C-, 31P-NMR and mass spectroscopic techniques. Compound 3 was also examined by X-ray crystallography and found to be crystallized in the monoclinic space group P21/n with the unit cell parameters: a = = 10.842(4), b = 9.375(5), c = 29.104(11) Å, β = 99.25(3)°, V = 2920(2) ų, Dx = 1.404 g cm-3. [ABSTRACT FROM AUTHOR]

Aliphatic/aromatic nitrogen-substituted ligands have a very important role in ruthenium chemistry. Polydentate ligands with N-substituted pyridine rings are notable for their ability to easily modify the electronic and steric properties of ruthenium. In this study, the catalytic and biological activities of the [RuCl 2 (NNN)(CH 3 CN)] (NNN: 2,6-di(1H-pyrazol-3-yl)pyridine)) complex were examined for two different applications. Firstly, the superb Ru(II) complex was used to catalyze the methanolysis of NaBH 4 , and its initial rate was calculated as 69360 mLH 2 min−1g cat −1. Secondly, the biological activities of the superb Ru(II) complex were examined. Accordingly, it was determined that this homogeneous complex showed anti-microbial activity on all bacteria used in the study, among the Gram-positive bacteria used in the study, the best result belongs to the Bacillus cereus EMC 19 bacterium with 8 mm, while among the Gram-negative bacteria, the best zone diameter belongs to the Pseudomonas aeruginosa DSM 50071 bacterium with 5 mm. However, it was observed that zone diameters varied between 8 mm and 3 mm. Compared to the control group, it was determined that 0.25 mg/mL concentration had 94.87%, 0.5 mg/mL concentration 96.10%, 1 mg/mL concentration 96.50%, and 2 mg/mL concentration 97.09% cytotoxic activity on the SH-SY5Y cell line. it was determined that all doses of the superb Ru(II) complex used in the study showed anti-cancer activity, but the anticancer activity shown at low doses was statistically more significant at the p < 0.05 level. [Display omitted] • Use of homogeneous superb ruthenium(II) complex during methanolysis of NaBH 4. • Kinetic studies for the superb Ru(II) complex catalyzing the methanolysis of NaBH 4. • Calculation of activation parameters for catalytic the methanolysis reaction. • Investigation of anti-cancer and anti-microbial properties of superb Ru(II) complex. [ABSTRACT FROM AUTHOR]