Twisted dinuclear Pd(II) complex with an exo-hexadentate ligand bearing bipyridine and carbamoly groups: Synthesis and structure

Dinuclear Pd(II) compound, [Pd₂(PMCB^2-)Cl₂] · CH₂Cl₂ (1), has been prepared by the reaction of K₂[PdCl₄] with exo-hexadentate ligand having amide groups (3,3′-bis[N-(2-pyridylmethyl)carbamoly]-2,2′-bipyridine, H₂PMCB) in H₂O/CH₂Cl₂. X-ray crystal structure of 1 indicates that one PMCB^2- ligand binds two Pd(II) ions each having a distorted square planar structure. The bipyridine group of the PMCB^2- ligand is involved in offset face-to-face π-π interactions, which gives rise to a 1D chain. The 1D chains are linked together via the C-H⋯O hydrogen bondings between a carbon atom of pyridine group and the oxygen of carbamoly group to generate a 2D network. Between the 2D networks there exist the herringbone π-π stackings, which results in a 3D supramolecular structure.