A novel style of 2D Hofmann-type coordination polymer incorporated trigonal prismatic coordination geometry with bidentate co-ligands

A novel 2D Hofmann-type framework was prepared with a bidentate co-ligand, 5,5′-dimethyl-2,2′-bipyridyl (dmbpy), which forces the curvature of the layer. X-ray diffraction analysis demonstrated that the coordination polymers, Mn^II(dmbpy)[M^VN(CN)₄] (M^V = Mn (1) and Cr (2)), formed a considerably corrugated 2D cyanide-bridged network with a quasi C_4v symmetric building unit, [Cr^VN(CN)₄]²⁻, and trigonal prismatic coordination geometry around Mn^II. Compound 2 demonstrated a metamagnetic-like ordering at 14.4 K, caused by the intra- and inter-layer antiferromagnetic interactions between Cr^V (S = 1/2) and Mn^II (S = 5/2), and a weak ferromagnetic behaviour at 2 K reflecting the single-ion anisotropy of Cr^V and structural anisotropy.