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 H-1 and C-13 shifts was enabled by the combination of C-13 editing, FSLG-HETCOR spectra, and 2D H-1-H-1 back-to-back (BABA) spectra with results from NMR-CASTEP calculations. The incorporation of Co2+ replacing Zn2+ ions in the MOP 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 H-1 T-1 relaxation time measurements.