Heterometallic NiIILnIII coordination compounds incorporating dicyanamides: Synthesis, crystal structures and magnetic properties

Three heterometallic Ni(II)-Ln(III) complexes (Ln = Ce, Pr, Sm), with the formulas [(Ni(mu-L)Ce(NO3)(dca) (mu-dca)]n (1), [Ni(mu-L)Pr(NO3)2(CH3OH)(dca)] (2) and [Ni(mu-L)Sm(NO3)(NO3-Cl)(mu-dca)] (3) were synthesized via one pot reaction using the compartmental ligand H2L and dicyanamide [H2L=6,6 '-((1E,1 ' E)-(ethane-1,2diylbis(azaneylylidene))bis(methaneylylidene))bis(2-methoxyphenol); dca= dicyanamide]. For complexes 1-3, all Ni atoms exhibit tetra-coordination with square (D4h) geometry, while all Ln (Ce, Pr and Sm) atoms display deca-coordination with sphenocorona (C2v) geometry. Complex 1 displays a one-dimensional (1D) infinite chain structure, where [NiIICeIII] dinuclear units form tetranuclear [NiIICeIII]2 clusters, bridged by dca ligands. Similarly, complex 3 exhibits a 1D chain structure, with [NiIISmIII] dinuclear units directly bridged by dca ligands. In contrast, complex 2 exists as isolated monomers, with dca acting as a terminal ligand. Additionally, the magnetic properties of these complexes were investigated and analyzed. These compounds represent rare examples of 3d4f magnetic materials derived from dca, with few reported instances.