Syntheses, Structures and Magnetic Properties of Novel Oxamido‐Bridged Tetranuclear Complexes [Cu 3 M] (M = Cu, Mn)

Three oxamido‐bridged tetranuclear complexes with the formulae [(LCu)Cu(LCuSCN) 2 ]·H 2 O ( 1 ), [(LCu)Mn(LCuSCN) 2 ]·1.38CH 3 OH ( 2 ) and {(LCu)Mn[LCuN(CN) 2 ] 2 }·0.75DMF·0.25H 2 O ( 3 ) (where H 2 L = 2,3‐dioxo‐5,6:15,16‐dibenzo‐1,4,8,13‐tetraazacylotetradeca‐7,13‐diene) have been prepared and characterised. Their structures were deduced using X‐ray crystallography. All three complexes crystallise in the triclinic system, space group P $\bar 1$ . The three copper ions of the complex ligands and the central metal ions (Cu, Mn) remain in the plane and form a scalene triangle. Three copper ions occupy the vertexes and the M(Cu, Mn) ions are located at the centre. Magnetic susceptibility measurements in the 5−300 K temperature range have been carried out for this series of complexes. The experimental data have been fitted according to the Heisenberg Hamiltonian and led to J values equal to −61.80 cm −1 , −14.54 cm −1 and −12.10 cm −1 for complex 1 , 2 and 3 , respectively. Their interaction parameters have been compared with each other. The deviation of the copper ions from the oxamide‐bridge plane results in the J value of complex 1 being different from those of other oxamide‐bridged copper complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)