Synthesis and Structural Features of [4,4'-Diisopropoxyester-2,2'-bipyridine], [Dichloro(4,4'-diisopropoxyester-2,2'-bi-pyridine)-platinum(ii)] and Its Dichloromethane Solvated Pseudo-Polymorph: Versatile Supramolecular Interactions

Abstract The organic ligand 4,4'-diisopropoxyester-2,2'-bipyridine, C₁₈H₂₀N₂O₄ (1), crystallizes in the triclinic crystal system P-1 and the molecule occupies a special position in the unit cell. In the crystal, molecules form stacks with partial overlapping of the pyridine rings. The Pt(II) dichloro complex of 1 crystallizes from a mixture of ethanol/hexane and from dichloromethane to form orange and yellow crystals, respectively. The orange non-solvated crystals of the (bipyridine)(dichloro)platinum(II) complex C₁₈H₂₀N₂O₄PtCl₂ (2) crystallize in the triclinic crystal system P-1 as well with two independent molecules in the unit cell. In the crystal packing, molecules form two types of dimers with Pt1⋯Pt1A and Pt2⋯Pt2A distances of 3.478 and 5.186 Å, respectively. The yellow crystals, as a solvated pseudo-polymorph C₁₈H₂₀N₂O₄PtCl₂·1.5 CH₂Cl₂ (3) also crystallize in the triclinic crystal system P-1 with two independent molecules in the unit cell. In the crystal packing, molecules form Pt2⋯Pt1⋯Pt1A⋯Pt2A intermolecular contacts with alternating distances 3.501 and 3.431 Å, respectively, forming infinite chains. Graphical Abstract: The dichloro(bipyridine)platinum complex, dichloro(4,4'-diisopropoxyester-2,2'-bipyridine)platinum(II), forms single crystals as a stable non-solvated form and a solvated polymorph with dramatically different supramolecular structure and short contacts.