Saavedra-Torres, M., Echevarria-Valdés, Y., Schott, E., Hidalgo-Rosa, Y., Paez-Hernandez, D., & Zarate, X. (2026). Periodic DFT investigation of Cu2+ coordination effects on a rhodamine/ZIF-8 chemical sensor: a ground-state electronic structure study. Computational Materials Science, 268, 114678. https://doi.org/10.1016/j.commatsci.2026.114678

Abstract: This study employs periodic density functional theory (DFT) calculations to investigate the structural and electronic effects of incorporating Cu²⁺ ions and Rhodamine B (RhB) as guest molecules into the ZIF-8 metal–organic framework (MOF). Three potential Cu²⁺ interaction sites in ZIF-8 were examined, revealing alterations in the density of states (DOS), particularly for interactions involving the methylimidazolate rings. RhB was modeled within the ZIF-8 pores, with its electronic impact assessed both alone and in combination with Cu²⁺. Fragment-based projected DOS (PDOS) and elemental shell analyses for Cu²⁺@ZIF-8 indicate significant contributions from Cu d- and s-orbitals to the valence band maximum (VBM) and conduction band minimum (CBM). Charge density difference (CDD) plots and Fukui function-derived reactivity indices further reveal electrophilic character at the Cu²⁺ site, suggesting potential charge-transfer pathways. These computational findings provide a perspective of the Cu²⁺ influence on the ZIF-8 framework, with small perturbation of the intrinsic electronic structure induced by RhB. The results provide atomic-level insights into the electronic origins of host–guest interactions in MOFs and guide the rational design on modified ZIF-8 structures.