Supramolecular Assemblies via Hydrogen Bonding and π-π Stacking Interactions: Crystal Structures of [Co(phen)(H2O)4]L·0.5H2O and [CO2(phen)2(H2O)2L2] with H2L = Adipic Acid

Abstract

Reaction of freshly-prepared CoCO3, phenanthroline monohydrate and adipic acid (H2L) in CH3OH/H2O produced a mixture of [Co(phen)(H2O)4]L·0.5H2O (1) and [CO2(phen)2(H2O)2L2] (2). Complex 1 crystallizes in the orthorhombic space group Pbcn with cell dimensions a = 23.380(2), b = 12.347(1), c = 12.821(1) Å, and D calc = 1.390 g/cm3 for Z = 8, and complex 2 in the triclinic space group P1; with cell dimensions a = 8.203(1), b = 9.809(1), c = 11.827(1) Å, α = 70.34(1), β = 74.81(1), γ = 71.54(1)° and D calc = 1.592 g/cm3 for Z = 1. Complex 1 consists of [Co(phen)(H2O)4]2+ complex cations, adipate anions and crystal H2O molecules. The Co atoms are each octahedrally coordinated by one chelating phen ligand and four water molecules with d(Co-O) = 2.041-2.097 Å and d(Co-N) = 2.144, 2.160 Å. Through hydrogen bonds, the [Co(phen)(H2O)4]2+ complex cations and adipate anions are interconnected into 2D layers, whose assembly could be ascribed to weak π-π stacking interactions between interdigitating phen ligands. Complex 2 is composed of centrosymmetric dinuclear [Co2(phen)2(H2O)2L2) molecules, in which the Co atoms are each coordinated by two N atoms of one chelating phen ligand and four O atoms of one H2O molecule and two adipato ligands to form distorted octahedra with d(Co-O) = 2.027-2.248 Å and d(Co-N) = 2.112, 2.162 Å. The centrosymmetric molecules are assembled via intermolecular hydrogen bonds and π-π interactions into 2D layers.