Magnetic and Electrochemical Properties of a Heterobridged μ-Phenoxido–μ1,1-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–μ1,1-azide dinickel(II) compound [NiII2(HL1)3(μ1,1-N3)]·3H2O (1) derived from the tetradentate Schiff base ligand N-(2-hydroxyethyl)-3-methoxysalicylaldimine (H2L1) are described. The title compound crystallizes in the triclinic system (space group P). Electrochemical analyses reveal that compound 1 exhibits two-step quasireversible couples in the reduction window with E1/2 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, D1 = 29.2 cm–1 and D2 = 10.7 cm–1). Comparison of the exchange integral of 1 with that of the only reported μ-phenoxido–μ1,1-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)