Synthesis and properties of a novel linear [Ni4L2(py)6] cluster: Designed ligand-controlled topology of the metals

摘要

A polydentate ligand, H4L, based on adjacent 1,3-diketone and phenol functions has been used in combination with a strong base for the assembly of four Ni(II) ions into molecular species, [Ni4L2(py)6] (1), featuring a targeted linear [Ni—Ni · · ·Ni—Ni] sequence. Weak antiferromagnetic exchange is observed within pairs of closest Ni(II) centers, of J = —5.04 cm~(-1) (in the H = — 2JS1S2 convention). An unusual combination of coordination geometries (square pyramidal + octahedral) is observed within each [Ni2] moiety in the molecule, attributed to the geometrical constraints imposed by L~(4-).