Two new ferromagnetic, end-on azide-bridged nickel(II)-dimers [{Ni(terpy)(N
-3)(2)}(2)]. H2O 1 and [Ni-2(terpy)(2)(N-3)(3)(H2O)]ClO4. H2O 2 (terpy = 2,
2' : 6',2 "-terpyridine) have been synthesized and magnetostructurally char
acterized through X-Ray single crystal analysis, IR spectroscopy and magnet
ic susceptibility measurements. The values of the Ni-N-Ni bridge angle and
the magnetic coupling constant, J, are 101.6 degrees and 22.8 cm(-1), respe
ctively, for 1 and 102.5 degrees and 13.6 cm(-1), respectively, for 2. The
influence of the Ni-N-Ni bridge angle on the magnetic performance of end-on
azide-bridged nickel(II) dimers has been studied by means of extended Huck
el molecular orbital calculations. The results indicate that the antiferrom
agnetic contribution of the global coupling constant decreases for increasi
ng bridge angle between 83 and 115 degrees.