Postsynthetic Modification of Amine-Functionalized MIL-101(Cr) Metal-Organic Frameworks with an EDTA-Zn(II) Complex as an Effective Heterogeneous Catalyst for Hantzsch Synthesis of Polyhydroquinolines

The present work aims at preparing the EDTA-Zn(II) complex-supported on the amine-functionalized MIL-101(Cr) MOF-as a new and effective heterogenized catalyst. The optimization of the hydrothermal process shows that 120 °C is the best condition to grow the MIL-101(Cr)-NH2 MOF crystals. Moreover, regarding the use of the postsynthetic modification (PSM) method, hexadentate EDTA was grafted on this support via a simple aminolysis process before further coordinating it with Zn ions to create the corresponding Zn(II) catalytic complex. The catalytic activity of this compound was then investigated in the context of a one-pot synthesis of polyhydroquinolines. This approach has a number of advantages including the following: the use of a solvent that is not hazardous, applying a porous catalyst that is inexpensive, secure, and recyclable; rapid reaction times, high levels of efficiency, and the simplicity of MOF catalyst separation. Accordingly, the process in question can be given the label of "green chemistry".

Unravelling the Metal Sensing Activity of a Biologically Relevant Fluorescent Crown Ether: A Unified Experimental and Theoretical Study

1,4-dihydropyridines (DHPs) are biologically active. 1,4-DHP analogs with appropriate substituents also show characteristic fluorescence activity. Here, for the first time, we report a simple and easy synthesis of a novel fluorescent 1,4- DHP derivative of dibenzo[18]-crown-6 (2), which showed promising sensing ability towards physiologically important metal ions. The covalent linking of 1,4-DHP analog with dibenzo[18]-crown-6 instigates its fluorescence activity in (2) and makes it biologically relevant. (2) shows a noteworthy enhancement of fluorescence intensity toward Fe3+ and Ba2+ in methanol medium. DFT studies revealed that metal binding by the crown ether-O atoms leads to structural rigidity, enhancing the fluorescence intensity. Interestingly, (2) shows utility in the quantitative detection of Fe3+ ions in the biological (human blood serum) and food samples.

Water compatible silica supported iron trifluoroacetate and trichloroacetate: as prominent and recyclable Lewis acid catalysts for solvent-free green synthesis of hexahydroquinoline-3-carboxamides

Silica supported iron trifluoroacetate and iron trichloroacetate green Lewis acid catalysts were developed by a novel, cheap, environment-friendly approach and utilized in the synthesis of hexahydroquinoline-3-carboxamide derivatives. The structure and morphology of the prepared Lewis acid catalysts were studied by FTIR, PXRD, FE-SEM, HR-TEM, EDX, BET, TGA and NH3-TPD techniques. The present catalysts shows maximum conversion efficiency in hexahydroquinoline-3-carboxamide derivatives synthesis at 70 °C in solvent free reaction condition with best product yield in a short reaction time. Both catalysts are reusable and simple to recover, and perform meritoriously in water as well as in a variety of organic solvents. The key advantages of the current synthetic route are permitting of a variety of functional groups, quick reaction time, high product yield, mild reaction condition, recyclability of catalyst and solvent-free green synthesis. This makes it more convenient, economic and environmentally beneficial.