A series of one-dimensional heterotrimetallic assemblies, [Cu 2Ln(L) 2(H 2O) 4][M(CN) 6]·nH 2O [Ln = Gd, M = Co (1), Fe (2), Cr (3), and Ln = La, M = Co (4), Fe (5), Cr (6)], were prepared by the reaction of a Cu 2Ln precursor complex, [Cu 2Ln(L) 2(NO 3) 3], with K 3[M(CN) 6] in water. All of the assemblies were isomorphous and formed a 1D zigzag chain, in which the [Cu 2Ln(L) 2(H 2O) 4] 3+ and [M(CN) 6] 3- units were alternately positioned and were linked in a Cu-NC-M-CN-Cu manner. Compound 1 showed magnetic behaviour similar to that of the discrete precursor complex, [Cu 2Gd(L) 2(NO 3) 3], owing to the diamagnetic nature of the [Co III(CN) 6] 3- unit. In the case of 2, a simple summation of the magnetic behaviour of the [Cu 2Gd(L) 2(H 2O) 4] 3+ and [Fe(CN) 6] 3- units was observed, whereas ferromagnetic interactions were found to be operative between the Cu 2+ and Cr 3+ ions in compound 3. The same magnetic interactions between Cu 2+ and M 3+ were confirmed in compounds 4 to 6, which included the diamagnetic La 3+ ion. The differences in the magnetic behaviours of 2 and 3 can be explained by the overlap of the dz2(Cu)-pπ(CN) orbitals in the bent Cu-N≡C linkage and the spin-density on the cyanide nitrogen of the [Cr(CN) 6] 3- unit.
All Science Journal Classification (ASJC) codes
- Inorganic Chemistry