title: 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.
abstract: The reaction of a methanolic solution containing M(ClO(4))(2)·nH(2)O (M = Cu, Ni, Zn or Cd) or CoCl(2)·6H(2)O with bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)amine (bedmpza) in the presence of NaN(3) afforded the complexes [Cu(bedmpza)(μ(1,1)-N(3))](2)(ClO(4))(2) (1), [Ni(bedmpza)(N(3))(μ(1,1)-N(3))](2)·1.5H(2)O (2), [Co(bedmpza)(N(3))(2)] (3), [Zn(bedmpza)(N(3))]ClO(4) (4) and [Cd(bedmpza)(N(3))(μ(1,1)-N(3))](2)·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)(μ(1,1)-N(3))](2)(ClO(4))(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.
authors: Department of Chemistry, University of Louisiana at Lafayette, P.O. Box 44370, Lafayette, LA 70504, USA. ssmassoud@louisiana.edu
authors: Salah S
authors: SS
authors: Massoud
authors: Febee R
authors: FR
authors: Louka
authors: Yasser K
authors: YK
authors: Obaid
authors: Ramon
authors: R
authors: Vicente
authors: Joan
authors: J
authors: Ribas
authors: Roland C
authors: RC
authors: Fischer
authors: Franz A
authors: FA
authors: Mautner