Synthesis, structure and magnetic properties of two end-on double azido bridged nickel(II) dinuclear entities incorporating <i>N,N,N</i>-coordinating tridentate reduced Schiff base ligands

Complexes of the general formula [Ni₂L₂ (μ_1,1-N₃)₂(N₃)₂] have been synthesised in good yields by reacting Ni(NO₃)₂ • 6H₂O with L in the presence of excess of sodium azide in methanol at room temperature. Here L is N,N-bis(2-pyridylmethyl)amine (L₁) and N-(2-pyridylmethyl)-<i>N′</i>,<i>N′</i>-diethylethylenediamine (L₂). The X-ray structures of both compounds reveal that the <i>N,N,N</i> coordinating reduced Schiff bases are ligated facially. The Ni–N_azido–Ni angle is 100° and the NiNi separation is 3.2 Å. The variable temperature magnetic susceptibility measurements of the two complexes show ferromagnetic behavior.