Isonicotinamide-Based Compounds: From Cocrystal to Polymer

The reaction between [Cu(μ-OAc)(μ-Pip)(MeOH)](2) (1) (OAc = acetate; Pip = 1,3-benzodioxole-5-carboxylate) and isonicotinamide (Isn) in MeOH as solvent yielded two mixture pairs of three compounds: {(HPip)(2)(Isn) (2), [Cu(Pip)(2)(Isn)(2)] (3)} and {(3), {[Cu(3)(Pip)(2)(OAc)(2)(μ-Isn)(2)(Isn)(2)(μ-OCH(3))(2)(MeOH)(2)]·2MeOH}(n) (4)}. Modifying the reaction conditions (t, T, molar ratio), 2 and 3 have been successfully isolated, whereas 3 and 4 had to be mechanically separated. The recrystallization of 3 in pentanol yielded single crystals of compound [Cu(Pip)(2)(Isn)(2)]·C(5)H(11)OH (3a). The X-ray crystal structure of 2, 3a, and 4 has been elucidated showing a cocrystal, a monomer, and an unusual coordination polymer, respectively. The Pip ligand exhibited a chelate (3a) or a monodentate (4) coordination mode, but the Isonicotinamide (Isn) ligand is the one that promoted the arrangement of different structures and also mainly directs the formation of the 2D and 3D supramolecular assemblies. All the structures have been analyzed by Hirshfeld surface. In addition, the energy frameworks and lattice energy values of 2 and 3a have been calculated.