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.