Synthesis, characterization and supramolecular structures of two Ni(II) complexes with potentially heptadentate ligand N,N<f>′</f>-bis(2-hydroxybenzyl)-1,3-bis[(2-aminoethyl)amino]-2-propanol

A potentially heptadentate ligand H3L (N,N<f>′</f>-bis(2-hydroxybenzyl)-1,3-bis[(2-aminoethyl)amino]-2-propanol) and its two Ni(II) complexes, [Ni(H2L)H2O](H2O)3ClO4 (1) and [Ni(H2L)(H2O)](H2O)Cl (2) were prepared and characterized. X-ray structural analyses indicate that complex 1 has a distorted octahedral coordination geometry, with four amine N atoms of H2L- defining the equatorial plane, one aqua O atom and one phenoxo O atom of the ligand occupying two axial positions, respectively. The Ni(II) center of 2 has coordination geometry similar to that of 1. IR and electronic spectra of 1 and 2 are in agreement with their crystal structural features. Approximately along the ab plane, 2D supramolecular structure of 1 is assembled through multiple hydrogen bonds between hydroxy groups of the ligands, coordinated and crystal lattice H2O and <f>π–π</f> stacking interactions between adjacent phenyl rings of the ligands, while for that of 2, probably along the a axis, 1D chain structure is also formed by multiple hydrogen bonds, but lack of <f>π–π</f> stacking interactions. [Copyright &y& Elsevier]