η3-allyl-Pd(II) complexes of 2-, 3-and 4-pyridylmethyl-coumarin esters

A series of 2-, 3- and 4-pyridylmethyl-coumarin esters ligands (1-3) and their eta(3)-allyl palladium complexes (1-Pd-3-Pd) have been designed, synthetized, and characterized. NMR analysis of compounds 1-Pd-3-Pd indicated the presence of the allyl fragment. The molecular structures of 2, 3 and 1-Pd were determined by X-ray crystallographic analysis. The molecular structure of 1-Pd reveals that coumarin ligand (2) is coordinated to the palladium center via a monodentate fashion through the nitrogen atom of the pyridinyl fragment while, the allyl group is binding via a eta(3) fashion in an overall square-planar geometry completed with a chloride atom. The crystal packing is stabilized by a variety of weak intermolecular conventional and non-conventional interactions involving C-H-O/N hydrogen bonds, pi-pi and C-H-pi interactions, which have been analyzed by Hirshfeld surface and non-covalent interactions analysis. The intermolecular interaction energies were explored using an energy framework analysis, which revealed that pi-pi and C-H-pi interactions serve as the primary building blocks in these crystal packing.

Automated summary

A series of pyridylmethyl-coumarin esters ligands and their eta(3)-allyl palladium complexes were designed, synthesized, and characterized. NMR analysis confirmed the presence of the allyl fragment in the palladium complexes. The crystal structures of the compounds were determined by X-ray crystallographic analysis, revealing the coordination modes and overall geometries. The crystal packing was stabilized by various weak intermolecular interactions, including hydrogen bonds, pi-pi, and C-H-pi interactions, which were analyzed using Hirshfeld surface and energy framework analysis.