Solid-state NMR data of transition-metal (Cu²⁺, Fe³⁺) cross-linked alginates

This dataset contains the solid-state nuclear magnetic resonance (ssNMR, Bruker, TopSpin) data acquired for alginate microbeads cross-linked by paramagnetic transition-metal ions (Cu2+ and Fe3+) and, for comparison, by diamagnetic Ca2+ ions. The samples correspond to those analyzed in the publication Urbanova et al., Carbohydrate Polymers 370, 2025, 124367 (https://doi.org/10.1016/j.carbpol.2025.124367). The dataset enables detailed inspection of 13C, 1H, and 23Na spectra measured under conventional and very-fast magic-angle spinning (MAS) conditions, as well as spectra of lactic-acid-modified systems. These data provide direct experimental evidence for the domain architecture, coordination environment, and network density of alginate gels containing paramagnetic metal centers.