Supramolecular Hydrogen‐Bond Structures and Magnetic Interactions in Basal‐Apical, Dinuclear, Azide‐Bridged Copper(<scp>II</scp>) Complexes

Abstract

Abstract The synthesis, characterisation, X‐ray single crystal structures and magnetic properties of three new basal‐apical μ 2 ‐1,1‐azide‐bridged complexes [CuL 1 N 3 ] 2 ( 1 ), [CuL 2 N 3 ] 2 ( 2 ) and [CuL 3 N 3 ] 2 ( 3 ) with very similar tridentate Schiff‐base blocking ligands {HL 1 = N ‐[2‐(ethylamino)ethyl]salicylaldimine; HL 2 = 7‐(ethylamino)‐4‐methyl‐5‐azahept‐3‐en‐2‐one; HL 3 = 7‐amino‐4‐methyl‐5‐azaoct‐3‐en‐2‐one} have been reported [complex 1 : monoclinic, P 2 1 / c , a = 8.390(2), b = 7.512(2), c = 19.822(6) Å, β = 91.45(5)°; complex 2 : monoclinic, P 2 1 / c , a = 8.070(9), b = 9.787(12), c = 15.743(17) Å, β = 98.467(10)°; complex 3 : monoclinic, P 2 1 / n , a = 5.884(7), b = 16.147(18), c = 11.901(12) Å, β = 90.050(10)°]. The structures consist of neutral dinuclear entities resulting from the pairing of two mononuclear units through end‐on azide bridges connecting an equatorial position of one copper centre to an axial position of the other. The copper ions adopt a (4+1) square‐based geometry in all the complexes. In complex 2 , there is no inter‐dimer hydrogen‐bonding. However, complexes 1 and 3 form two different supramolecular structures in which the dinuclear entities are linked by H‐bonds giving one‐dimensional systems. Variable temperature (300−2 K) magnetic‐susceptibility measurements and magnetisation measurements at 2 K reveal that all three complexes have antiferromagnetic coupling. Magneto‐structural correlations have been made taking into consideration both the azido bridging ligands and the existence of intermolecular hydrogen bonds. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2004)