Synthesis of the Trans-bidentate Ligand 1,2-Bis(Quinolin-2-ylethynyl)Benzene and the X-ray Crystal Structure of Its Complex with Palladium(II) Chloride

A new trans-bidentate ligand, 1,2-bis(quinolin-2-ylethynyl)benzene, was synthesized and coordinated to PdCl₂. The structure of the acetonitrile solvate of this species was determined by single-crystal X-ray diffraction. The complex crystallizes in the orthorhombic space group Ibam, with a = 25.0726(18) Å, b = 11.7373(6) Å, and c = 18.9700(10) Å in a layered structure. When bound to 1,2-bis(quinolin-2-ylethynyl)benzene, the Pd(II) metal center displays a distorted square planar geometry. This coordination complex was compared to PdCl₂-coordinated 1,2-bis(2-pyridylethynyl)benzene, a previously reported trans-bidentate ligand. Structural comparison indicated that the binding pocket for these two trans-bidentate ligands are similar, though the 1,2-bis(quinolin-2-ylethynyl)benzene ligand is somewhat more planar.

Graphical Abstract

A new trans-bidentate ligand, 1,2-bis(quinolin-2-ylethynyl)benzene (BQEB), was synthesized and coordinated to PdCl₂.