Syntheses, crystal structures and characterizations of tetraazamacrocyclic complexes meso -[Ni(1,7-CT)]I2 and dl -[Ni(1,7-CT)][Fe(CN)5NO] · H2O

Abstract

A centrosymmetric meso tetraazamacrocyclic nickel(II) complex meso-[Ni(1,7-CT)]I2 (1) and a novel racemic ion-pair double complex dl-[Ni(1,7-CT)][Fe(CN)5NO] · H2O (2) (1,7-CT = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-1,7-diene) have been synthesized and characterized by elemental analyses, single crystal X-ray diffraction, 1H NMR, IR, UV-vis spectra and TG-DTA analyses. Results reveal that the structure of 1 consists of the overlapping meso-[Ni(1,7-CT)]2+ cation with the perfect square-planar NiN4 chromophore and outer iodides. Compound 2 contains four kinds of structurally distinct ion-pairs a, a′, b and b′ that are made up of distorted square dl-[Ni(1,7-CT)]2+ cations and distorted octahedral [Fe(CN)5NO]2− anions, which are divided into two groups with an enantiotropic relationship between them in each group. They are linked by van der Waals forces and hydrogen bonds involving H2O and arranged alternatively in adjacent layers, forming an orderly three-dimensional network structure.