Ni(II) complexes of stereo-isomeric hexazamacrocyclic ligands derived from 2,6-diacetylpyridine

摘要

The nitrate and perchlorate Ni(II) complexes of the stereo-isomeric hexazamacrocyclic ligands L-1(3,6,14,17,23,24-hexaazatricyclo[17,3,1,18,12]tetracosa-1(23),8,10,12 (24),19,21-hexaene,2,7,13,18-tetramethyl) and L-2 (3,7,15,19,25,26-hexaazatricyclo[19,3,1,19,13]hexacosa-1(25),9,11,13(26) ,21,23-hexaene,2,8,14,20-tetramethyl) derived from 2,6-diacetylpyridine have been synthesized and characterized by microanalysis, LSI-MS, conductivity measurements, IR, UV-Vis spectroscopy and magnetic studies. Crystal structures of L-1 center dot 2H(2)O as well as of the complexes [NiL1](ClO4)(2) and [NiL2](NO3)(2) have been determined. The X-ray studies show the presence of mononuclear endomacrocyclic complexes with the metal ion coordinated to all the nitrogen donor atoms from the macrocyclic framework in a N6 core. The geometry around the metal ions can be described as distorted octahedral. The nitrate and perchlorate anions do not coordinate to the metal ions, but they are involved in intermolecular interactions through hydrogen bonds to the amine groups of the macrocyclic ligands.