Synthesis, Structure and Properties of a Mononuclear and an End‐On Double Azido‐Bridged Copper( II ) Complex Incorporating an N,N,N,O‐Coordinating Tripodal Ligand

The blue coloured complex [Cu(HL)(H 2 O)(ClO 4 )]ClO 4 ·H 2 O·MeOH ( 1· H 2 O·MeOH) has been synthesised in excellent yields by reacting Cu(ClO 4 ) 2 ·6H 2 O with N , N ‐bis(2‐methylpyridyl)(3,5‐dimethyl‐2‐hydroxybenzyl)amine (HL) in methanol. The same reaction, when carried out in the presence of sodium azide, afforded a dark‐blue complex of formula [Cu 2 (HL) 2 (μ‐1,1‐N 3 ) 2 ](ClO 4 ) 2 ( 2 ). The crystal and molecular structures of the complexes have been solved. Variable‐temperature magnetic susceptibility data in the range of 2−300 K for 2 reveal the existence of an antiferromagnetic interaction through an end‐on azido linker. Temperature‐dependent susceptibility studies for 2 were fitted using the Bleaney−Bowers expression, which led to the parameters J  = −3.2 cm −1 , g  = 2.12 and R  = 2.14 × 10 −4 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)