Synthesis of Pd +2 complexes of Schiff bases containing methyl 2-amino-6-benzyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate and spectral and catalytic activities

Here in, ONS-donor atom containing Schiff base ligands ( 1, 2 ) was used to prepare 1a and 2a complexes. The Schiff base ligands were synthesized using 2-hydroxy-3-methoxybenzaldehyde and 4-benzoxybenzaldehyde with methyl 2-amino-6-benzyl-4,5,6,7-tetrahydrothieno[2,3- c ]pyridine-3carboxylate as precursors in ethanol medium. Pd(II) complexes (1a, 2a) were prepared using the corresponding [PdCl 2 (CH 3 CN) 2 ] and Schiff base in a (1:1) molar proportion. The Schiff bases ( 1, 2 ) and their Pd(II) complexes ( 1a, 2a ) were then identified via various analytical/spectroscopic methods ( 1 H and 13 C) NMR, UV- Vis spectra, FT-IR, mass, TGA and CHNS to determine their molecular structures. Finally, the results obtained based on Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions show that electrondonating and electron-withdrawing substituents on the aryl halide might produce coupling products in excellent yield in the presence of 1a, 2a complexes (as catalysts) under optimum conditions. (c) 2022 Elsevier B.V. All rights reserved.