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 T1 relaxation time measurements.