Synthesis, Crystal Structure, and Electron Paramagnetic Resonance Investigations of Heteronuclear CoII/ZnII and CoII/CdII Coordination Polymers

The crystal structures of five new CoII, ZnII, and CdII coordination polymers based on pyridine-substituted triazolyl carboxylates are reported. The two isomorphous compounds ∞3[M(Me-3py-pba)2] (M = Zn, Co) possess {66} topology (dia). In order to obtain heteronuclear compounds, we synthesized CoII-substituted ZnII and CdII coordination polymers. At T = 5 K, the powder samples of the diamagnetically diluted CoII/ZnII and CoII/CdII systems [Co/(Zn,Cd) ≈ 0.01] show intense electron paramagnetic resonance spectra, which were analyzed with an effective spin of S′ = 1/2. The g tensor as well as the 59Co hyperfine tensor ACo are strongly anisotropic. The g tensor components are used to gain information about the symmetry of the CoII coordination sphere and covalency effects. Differential thermal analysis/thermogravimetry−mass spectrometry and temperature-dependent powder X-ray diffraction studies reveal high thermal stability of the three-dimensional coordination polymers up to 390 °C.