A spin-crossover phenomenon in a 2D heterometallic coordination polymer with [Pd(SCN)4]2− building blocks

Abstract

Two new two-dimensional (2D) coordination polymers, [Fe^II(L)₂{Pd^II(SCN)₄}] (L₁ = 3-(9-anthracenyl)-pyridine (1) and L₂ = 4-(9-anthracenyl)-pyridine (2)), were constructed by employing square-planar [Pd(SCN)₄]²⁻ building blocks. Compound 1 exhibits a complete spin-crossover (SCO) behaviour under normal atmospheric pressure, and represents the first SCO example in a 2D system containing [Pd(SCN)₄]²⁻ units. In contrast, compound 2 only shows paramagnetic behaviour at measured temperatures. It is clear that the fine-tuning of the monodentate ligand can modulate the ligand field and packing fashions, which sheds light on developing new SCO materials.