Preparation and spectroscopic studies of Fe(II), Ru(II), Pd(II) and Zn(II) complexes of Schiff base containing terephthalaldehyde and their transfer hydrogenation and Suzuki-Miyaura coupling reaction

Abstract

This study describes synthesis, spectroscopic characterization and catalytic activities of Fe(II), Ru(II), Pd(II) and Zn(II) complexes with a novel Schiff base ligand (L) derived from methyl 2-amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate and terephthalaldehyde. We used spectroscopic techniques including IR, UV-Vis, 1H-NMR, 13C-NMR, elemental analysis and also mass analysis and magnetic susceptibility measurements to identify the products. The Pd(II) complex was used as a potential catalyst for Suzuki-Miyaura coupling reaction of some aryl halides under optimized conditions. The effect of various bases such as NaOH, KOH, and KOBut was investigated in transfer hydrogenation (TH) of ketones by isopropyl alcohol as the hydrogen source. Ru(II) and Pd(II) complexes showed catalytic activity while Zn(II) and Fe(II) metal complexes failed to do that.

Schiff Base-Pd(II) Complexes Containing Pyridine and Thiophene Rings: Synthesis, Characterization, Suzuki-Miyaura C-C Coupling Reactions

“…Pd(II) complexes (1a-d) showed a low energy band in the range of 504-343 nm for MLCT (metal to ligand charge transfer) transitions. These results may suggest that Pd(II) complexes had a square-planar geometry [6,[22][23][24][25][26].…”

Synthesis and Characterization of Azo Dye Complexes as Potential Inhibitors of Acetylcholinesterase, Butyrylcholinesterase, and Glutathione S‐Transferase

“…Ru(II) complex showed strong absorption peak at 217–322 nm due to π→π* transition and a lower energy broad absorption band at 383–467 nm region due to metal‐to‐ligand charge transfer (MLCT) [29] . Based on the model of the electronic spectra of similar complexes in the literature, the formation of an octahedral structure around the Ru(II) ion is supported [30] …”

“…[29] Based on the model of the electronic spectra of similar complexes in the literature, the formation of an octahedral structure around the Ru(II) ion is supported. [30] ChemistrySelect…”

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“…Schiff-bases (Scheme 1) was prepared by usual condensation reaction 9 , by adding salicylaldehyde (0.1 mole) drop wisely to (0.1 mole) benzocaine with continuous stirring (drops of triethylamine 10,11 and glacial acetic acid 1, 12 was added). After complete addition, the reaction refluxed for about 3 h. After cooling to room temperature, the products (imines) were separate by filtration.…”