Metal ions directing the geometry and nuclearity of azido-metal(II) complexes derived from bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)amine

The reaction of a methanolic solution containing M(ClO4)(2)center dot nH(2)O (M = Cu, Ni, Zn or Cd) or CoCl2 center dot 6H(2)O with bis(2-(3,5-dimethyl-1H-pyrazol-1-yl) ethyl) amine (bedmpza) in the presence of NaN3 afforded the complexes [Cu(bedmpza)(mu(1,1)-N-3)](2)(ClO4)(2) (1), [Ni(bedmpza)(N-3)(mu(1,1)-N-3)](2 center dot)1.5H(2)O (2), [Co(bedmpza)-(N-3)(2)] (3), [Zn(bedmpza)(N-3)]ClO4 (4) and [Cd(bedmpza)(N-3)(mu(1,1)-N-3)](2)center dot 1.5H(2)O (5). The five complexes were characterized by spectroscopic techniques and their molecular structures were determined by single crystal X-ray crystallography. The two mononuclear complexes 3 and 4 display distorted TBP and tetrahedral geometry, respectively with the azide ions acting as monodentate ligands. Doubly bridged end-on-azido dinuclear complexes were obtained in the remaining compounds. Compounds 2 and 5 are isomorphic with distorted octahedral geometry, whereas distorted square pyramidal geometry was determined in the Cu(II) complex 1. The magnetic properties for complexes 1 and 2 were investigated by measuring the magnetic susceptibilities at variable temperatures (300-2 K). The Ni(II) complex exhibits moderate ferromagnetic coupling, whereas [Cu(bedmpza)(mu(1,1)-N-3)](2)(ClO4)(2) (1) which contains two crystallographic independent dinuclear subunits in the unit cell, with different Cu-N(N3)-Cu bond angles, reveals different signs in the magnetic coupling. The complex represents the first example in the literature that has simultaneously two moieties with ferro- (J = 15.4 cm(-1)) and antiferromagnetic (J = -18.9 cm(-1)) interactions.