Three-dimensional acentric coordination polymers formed from the linkage of cobalt and nickel malonate quadratic layers through a kinked organodiimine: Synthesis, structure, thermal properties and magnetochemistry

Hydrothermal synthesis has afforded a pair of isostructural acentric three-dimensional coordination polymers {[M2(malonate)2(dpa)(H2O)2] · 2H2O}n (M = Co, 1; M = Ni, 2; dpa = 4,4′-dipyridylamine), which were structurally characterized via single-crystal X-ray diffraction and spectroscopically and thermally analyzed. Both materials exhibit exotridentate malonate ligands conjoining metal atoms into grid-like [M(malonate)(H2O)]n layers; in turn, these are connected into 3-D sqp lattices (4466 topology) through tethering dpa ligands. The central kink and inter-ring torsion within the dpa ligands enforces the acentric Aba2 space group of crystals of 1 and 2. Antiferromagnetic coupling (g = 2.08(2), J = –1.05(8) cm−3) was observed within the malonate-bridged layer motifs within the cobalt derivative 1. In contrast, the nickel congener 2 exhibited ferromagnetic coupling (g = 2.201(1), J = 0.289(1) cm−3).

Graphical abstractA pair of isostructural acentric 3-D coordination polymers {[M2(malonate)2(dpa)(H2O)2] · 2H2O}n (M = Co, 1; M = Ni, 2; dpa = 4,4′-dipyridylamine) with 3-D sqp network topology have been synthesized. Antiferromagnetic coupling was observed within the malonate-bridged layer motifs in 1; in contrast, 2 exhibited ferromagnetic coupling.Figure optionsDownload full-size imageDownload as PowerPoint slide