Synthesis, Crystal Structure, and Solid-State NMR Investigations of Heteronuclear Zn/Co Coordination Networks  A Comparative Study

Synthesis and solid-state NMR characterization of two isomorphous series of zinc and cobalt coordination networks with 1,2,4-triazolyl benzoate ligands are reported. Both series consist of 3D diamondoid networks with four-fold interpenetration. Solid-state NMR identifies the metal coordination of the ligands, and assignment of all ¹H and ¹³C shifts was enabled by the combination of ¹³C editing, FSLG-HETCOR spectra, and 2D ¹H–¹H back-to-back (BABA) spectra with results from NMR-CASTEP calculations. The incorporation of Co²⁺ replacing Zn²⁺ ions in the MOF over the full range of concentrations has significant influences on the NMR spectra. A uniform distribution of metal ions is documented based on the analysis of ¹H <i>T</i>₁ relaxation time measurements