One-dimensional coordination polymers constructed from di- and trinuclear {3d-4f} tectons. A new useful spacer in crystal engineering: 1,3-bis(4-pyridyl)azulene

Four new heterometallic 3d-4f complexes have been obtained using bi-and trinuclear building blocks: 1(infinity)[Ni(L-1)Gd(NO3)(3)(azbbpy)]center dot CH3CN (1), [Zn(L-1)Eu(NO3)(3)(azbbpy)]center dot H2O(2), 1(infinity)[(CuL2)(2)Gd(NO3)(2)(dca)] 3 and 1(infinity)[(NiL2)(2)Dy(H2O)(4)(oxy-bbz)]NO3 center dot 3H(2)O (4), [H2L1 = 1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol), H2L2 = 2,6-di(acetoacetyl) pyridine, azbbpy = 1,3-bis(4-pyridyl) azulene, dca(-) = dicyanamide anion, and oxy-bbz = the dianion of the 4,4'-oxy-bis(benzoic) acid]. 1 and 2 represent the first complexes containing 1,3-bis(4-pyridyl) azulene as a ligand. 1, 3, and 4 are one-dimensional coordination polymers constructed from heterometallic nodes connected by the exo-dentate ligands. Helical chains are assembled in the case of 4. The analysis of the packing diagram for 1 reveals the occurrence of p-p stacking interactions established between the azulene rings from neighboring chains, which lead to supramolecular layers. The magnetic properties of 3 in the temperature range 1.9-300 K have been investigated. Intra-node ferromagnetic interactions are established between the Cu-parallel to and Gd-parallel to ions (J = + 2.7 cm(-1), H = -J(S-Cu center dot S-Gd + S-Cu center dot S-Gd).