A novel nanomagnetic palladium (II) complex of bisimidazolium-based N–heterocyclic carbene; An efficient heterogeneous catalyst for A3 coupling reactions

Althomali R.H.; Abbood M.K.; Altalbawy F.M.A.; Saleh E.A.M.; Abdullaev S.S.; Ibrahim A.J.; Ansari S.A.; Romero-Parra R.M. · Journal of Molecular Structure (2023) · DOI: 10.1016/j.molstruc.2023.135911

Resumen

Herein, a novel nanomagnetic NHC-Palladium complex was successfully prepared applying post-synthetic modification (PSM) condensation between Fe3O4-support imidazole and a synthetic bisamide moiety, carrying the alkyl halide functionalities at the end of its chain, followed by chelation of Pd ions to generate the corresponding complex. The [Fe3O4@bisimidazolium-Pd]2Cl− complex gave the best catalytic performance in synthesizing propargylamines through A3 coupling of various substituted aromatic and cycloaliphatic aldehydes and secondary amines with aromatic and liner alkynes in PEG-400. Primary amines are inefficient to produce unknown byproducts; whereas, secondary amines react quickly. Significantly, alkynes having a high electron density reduce the conversion rate. Moreover, aromatic and aliphatic aldehydes are active, but the electron-drawing substituent on benzaldehyde decreases the rate of conversion. Furthermore, the [Fe3O4@bisimidazolium-Pd]2Cl− catalyst can be reused seven times without metal leaching or losing its ability, which shows how stable it is when used in a reaction.

Instituciones: Universidad Continental