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A novel methodology for the synthesis of 2-pyridones bearing a 2-pyridyl group on nitrogen and carbon atoms, starting from 2-bromopyridines, was developed employing a simple Ru(II)–KOPiv–Na2CO3 catalytic system. Unsubstituted 2-bromopyridine was successfully converted to the penta-heteroarylated 2-pyridone product using this method. Preliminary mechanistic studies revealed a possible synthetic pathway leading to the multi-heteroarylated 2-pyridone products, involving consecutive oxygen incorporation, a Buchwald–Hartwig-type reaction, and C–H bond activation. [ABSTRACT FROM AUTHOR]

This work explores the synthesis and DFT study of five tetranuclear Pb(II) complexes and the role of tetrel bonding in their crystal engineering. Three synthesised Pb(II) complexes and two theoretical tetrameric Pb(II) complexes with halogenated thiophene carboxylate and 1,10-phenanthroline ligands are reported here. Their structural configurations, which feature chair-like repeating units connected via oxygen bridges, without Pb–Pb bonds, show two types of packing arrangements. Each Pb atoms form hemidirectional coordination creating space for the formation of tetrel bonds. The close packed arrangements are stabilised and guided by tetrel bonds. The Pb⋯Br tetrel bonds were found to contribute −4.38 kcal mol−1 and Pb⋯Cl −3.37 kcal mol−1 for the stability of the complexes. These tetrel bonds direct the packing arrangements within the crystal lattice. Additionally, open packed arrangements are stabilised by hydrogen bonds. These findings offer new insights into the design of lead-based metal organic frameworks and highlights the critical role of tetrel bonds in the crystal architecture. [ABSTRACT FROM AUTHOR]

The N1,N2‐diphenyloxalohydrazide OX(HA)2 chemosensor was synthesized and used as a colorimetric and fluorescent receptor to detect Cu2+ and Fe3+ ions in the presence of other metal ions. A range of physicochemical approaches were utilized to characterize the symmetrical oxalohydrazide‐based receptor, including FT‐IR, 1H and 13C NMR, TGA, and mass spectrometry. According to single crystal X‐ray diffraction investigation, OX(HA)2 crystallizes in monoclinic with space group C2/c. UV‐Vis and fluorescence spectroscopy were used to thoroughly explore OX(HA)2's sensing capabilities towards diverse cations. Using measurements of fluorescence intensity, the binding constant for OX(HA)2 with Cu2+/Fe3+ ions was calculated to be 2.78×103 M−1 and 1.12×103 M−1 with the lower detection limit of 0.43 μM and 0.2 μM respectively. With a 1 : 1 binding mechanism validated by Job's plot, mass spectral analysis, FT‐IR spectra, and density functional theory, the dual‐sensing receptor exhibits remarkable selectivity and sensitivity towards Cu2+ and Fe3+ ions. The average fluorescence lifetimes of OX(HA)2, OX(HA)2+Cu2+, and OX(HA)2+Fe3+ were calculated to be 2.19 ns, 1.73 ns, and 1.26 ns, respectively. This fluorescence lifetime measurement results strongly support the complexation of Cu2+ and Fe3+. When Cu2+ and Fe3+ ions bind with OX(HA)2, they induce the 'Turn‐Off' signal. Then, fluorescence imaging of the OX(HA)2 receptor in MDA‐MB‐231 demonstrated that the receptor holds a lot of promise for usage in bioimaging and their IC50 value for cytotoxicity is 96.96 μg. Furthermore, fluorescence microscopy experiments demonstrate that OX(HA)2 can be utilized as a fluorescent probe for detecting Cu2+ and Fe3+ ions in living cells, making it potentially helpful as an anticancer medication. [ABSTRACT FROM AUTHOR]

Six symmetrical 3,6‐diaryl (aryl=phenyl, 2‐, 3‐ and 4‐tolyl, 2,4‐ and 3,5‐xylyl) substituted furo[3,4‐c]furanones (DFF) were synthesized. The computational analysis, based on density functional theory, found eight possible centrosymmetrical slipped π‐stack arrangements, formed according to electron repulsion minimization principle, as for previously reported for π‐isoelectronic diketopyrrolopyrroles (DPP). One of these slipped stack arrangements was found to form infinite columns in the crystals of a new polymorph of parent phenyl derivative (with centre‐to‐centre distance CC=6.975 Å), other three types of stacks were found for 3‐tolyl (CC=6.153 Å), 4‐tolyl (CC=3.849 Å) and 2,4‐xylyl (CC=4.856 Å) derivatives by single crystal X‐ray diffractometry. All six derivatives show intense solution fluorescence in blue/green region, with a maximum driven entirely by a number and position of methyl substituents on phenyl rings. On the other hand, the solid‐state fluorescence from yellow over orange to red is observed only for four derivatives and its presence/absence, spectral position and vibronic structure is driven exclusively by the slips in π‐stacks (with interplanar distance always less than 3.5 Å) of almost planar DFF molecules, resulting in J‐type emission, H‐type excimer‐like emission and H‐type quenching. [ABSTRACT FROM AUTHOR]

We describe the synthesis of a symmetrical N,N′-bis(3-(1H-imidazol-1-yl)propyl)oxalamide-based receptor OX(PID)2 and its characterization by different physicochemical techniques, namely FT-IR, 1H and 13C NMR, TGA, and mass spectrometry. Single crystal X-ray diffraction analysis shows that OX(PID)2 crystallizes in monoclinic space group P21/c. The sensing capability of OX(PID)2 towards various cations has been exhaustively investigated using UV-vis and fluorescence spectroscopy. OX(PID)2 shows high selectivity and sensitivity towards Cu2+ and Fe3+ ions with a 1 : 1 binding ratio over other metal ions, which was highly supported via Job's plot and density functional theory calculations. The Cu2+ and Fe3+ ions induce the 'turn-off' signal when interacting with OX(PID)2. Moreover, using four different bacterial species, including S. aureus, B. subtilis, E. coli, and K. pneumonia, the biological activities of the newly created oxalamide-based compounds were assessed against various pathogenic bacteria and compared to streptomycin as a reference drug. Our substances exhibit moderate to good vital action against the aforementioned harmful microorganisms, according to the results. Then, fluorescence imaging in MDA-MB-231 on receptor OX(PID)2 suggested that OX(PID)2 had great potential in the application of bioimaging. The receptor with Cu2+ or Fe3+ ions was found to be cytotoxic against MDA-MB-231 and could be used as an anticancer agent. [ABSTRACT FROM AUTHOR]