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

Abstract

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 (1)H and (13)C shifts was enabled by the combination of (13)C editing, FSLG-HETCOR spectra, and 2D (1)H-(1)H back-to-back (BABA) spectra with results from NMR-CASTEP calculations. The incorporation of Co(2+) replacing Zn(2+) 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 (1)H T1 relaxation time measurements.