Magnetic and Electrochemical Properties of a Heterobridged μ‐Phenoxido–μ 1,1 ‐Azide Dinickel(II) Compound: A Unique Example Demonstrating the Bridge Distance Dependency of Exchange Integral

The synthesis, structure, magnetic and electrochemical properties of the heterobridged μ‐phenoxido–μ 1,1 ‐azide dinickel(II) compound [Ni II 2 (HL 1 ) 3 (μ 1,1 ‐N 3 )] · 3H 2 O ( 1 ) derived from the tetradentate Schiff base ligand N ‐(2‐hydroxyethyl)‐3‐methoxysalicylaldimine (H 2 L 1 ) are described. The title compound crystallizes in the triclinic system (space group P $\bar {1}$ ). Electrochemical analyses reveal that compound 1 exhibits two‐step quasireversible couples in the reduction window with E 1/2 values of –1412 and –1762 mV. The variable‐temperature (2–300 K) magnetic susceptibilities at 1 T of the title compound were measured. The interaction between the metal centres is weak ferromagnetic ( J = 5.0 cm –1 , g = 2.23, D 1 = 29.2 cm –1 and D 2 = 10.7 cm –1 ). Comparison of the exchange integral of 1 with that of the only reported μ‐phenoxido–μ 1,1 ‐azide dinickel(II) compound results in the emergence of a unique example of the dependence of strength of magnetic exchange interaction on the metal–ligand bridge distance. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)