Supramolecular rectangles and ladders constructed from Ni(II), Cu(II) and Zn(II) mononuclear complexes with bicompartmental ligands and 4-aminopyridine as tectons

Abstract

Abstract By reacting [MII(valpn)] or [MII(valdmpn)] mononuclear complexes with 4-aminopyridine in different molar ratios, five [MII(valXpn)(4-NH2-py)] and one [NiII(valdmpn)(4-NH2-py)2] complexes were obtained and structurally characterized (MII = NiII, CuII, ZnII; valpnH2 and valdmpnH2 are the Schiff bases resulted from the condensation of o-vanillin with 1,3-propylenediamine and 2,2-dimethyl-1,3-propylenediamine respectively). In the [Cu(valpn)(4-NH2-py)], [Ni(valpn)(4-NH2-py)], [Zn(valpn)(4-NH2-py)] and [Ni(valdmpn)(4-NH2-py)] complexes the metal ions are pentacoordinated with a square pyramidal geometry. The specific hydrogen bond interactions of the amino group belonging to the 4-aminopyridine with the free O2O′2 compartment of the Schiff base ligands led to various supramolecular architectures: rectangles, chains, and ladders. The spectroscopic properties of the compounds were also investigated.