Cyano‐Bridged Dimetallic Polynuclear Cu 6 Cr, Cu 6 Cr 6 , Cu 2 W, and CuW Arrays: Synthesis, Crystal Structure, and Magnetism

The synthesis, structure, and properties of the dimetallic complexes [CuLCr(CN) 6 ] 6 ·[{CuL(H 2 O)} 6 Cr(CN) 6 ](ClO 4 ) 3 · 16H 2 O ( 1 ), [CuLCr(CN) 5 (NO)] 6 ·[{CuL(H 2 O)} 6 Cr(CN) 5 (NO)](ClO 4 ) 3 ·16H 2 O ( 2 ) and [CuL] 3 [W(CN) 8 ] 2 ·4H 2 O ( 3 ) {L = 3,7‐bis(2‐aminoethyl)‐1,3,5,7‐tetraazabicyclo[3.3.2]decane} are presented. The structures of 1 and 2 are isomorphous and consist of novel cyano‐bridged [CuL(μ‐CN) 2 Cr(CN) 4 ] 6 dodecanuclear units and [CuL(H 2 O)(μ‐CN)] 6 Cr heptanuclear moieties. Every cyclic dodecanuclear Cu 6 Cr 6 group embeds a ClO 4 − anion. The heptanuclear and the dodecanuclear units are connected through hydrogen bonds to generate a vacant hole, in which another ClO 4 − anion is accommodated. Complex 3 contains cyano‐bridged Cu 2 W trimers and CuW dimers. Magnetic studies have shown that the three complexes display ferromagnetic coupling across the Cr−CN−Cu or W−CN−Cu linkages. The best fit to the magnetic data gave for complex 1 J CuCr = +2.40 cm −1 , g Cr = 1.99, g Cu = 2.09, and an intermolecular coupling constant θ = +0.23 K while for complex 2 J CuCr = +12 cm −1 , g = 2.13, and θ = −0.49 K. Ferromagnetic Cu II ‐W V coupling is operative in complex 3 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)