The interplay of O–H⋯O hydrogen bonding in the generation of three new supramolecular complexes of CuII, NiII and CoIII: Syntheses, characterization and structural aspects

Three new coordination complexes, [Cu(L1)(H2O)] (1), [Ni(L2)2]·CH3CN (2) and [Co(HL3)(L3)] (3) [where H2L1, N,N′-bis(3-methoxysalicylidenimino)-1,3-diamino-propane; HL2, 2-((E)-(1,3-dihydroxy-2-methylpropan-2-ylimino)methyl)phenol; H2L3, 2-((E)-(2-hydroxyethylimino)methyl)-4-bromophenol] have been synthesized and systematically characterized by elemental analyses, FT-IR, electronic spectroscopy, cyclic voltammetry and thermogravimetric analyses. Single crystal X-ray diffraction studies confirm that the metal center in complex 1 has distorted square-pyramidal geometry while it is distorted octahedral in the other two complexes. In all the complexes O–H⋯O hydrogen bondings assemble the molecular units leading to ordered supramolecular architectures. While both complexes 1 and 2 form infinite one-dimensional arrays through the self organisation of hydrogen bonded ring motifs, complex 3 is a unique star-shaped cyclic hexamer generated through intermolecular hydrogen bonding.