A Supramolecular Dimer of Two Crystallographically Independent Co(II) Phthalate Bipyridine Complexes in One Single Crystal: Synthesis, Crystal Structure, and Thermal Studies

Abstract

A cobalt(II) complex with 2,2′-bipyridine and phthalate ligands of the composition [Co(bpy)(Hpht)(H₂O)₃][Co(bpy)(pht)(H₂O)₂]Cl·2H₂O (bpy: 2,2′-bipyridine; Hpht, pht: o-phthalate anions) are synthesized and characterized by FT-IR and electronic spectroscopy and single crystal X-ray diffraction. The compound crystallizes in the triclinic system, space group, Z = 2 with a = 11.998(5), b = 13.956(5), c = 14.313(5) Å, α = 112.33(5), β = 95.067(5), γ == 109.166(5)°. The structure consists of a cationic complex unit [Co(bpy)(Hpht)(H₂O)₃]⁺, a neutral complex unit [Co(bpy)(pht)(H₂O)₂], a chloride anion, and two lattice water molecules. The intermolecular O-H⋯O hydrogen bond links two independent Co(II) complexes in the crystal structure, forming a supramolecular dimer. The dimers in the crystal form a 2D layered network structure via weak supramolecular π-π stacking, C-H⋯O, C-H⋯Cl, and O-H⋯Cl hydrogen bonding interactions. The thermal behavior of the compound is investigated.