Terbium(III), europium(III), and mixed terbium(III)–europium(III) mucicate frameworks: hydrophilicity and stoichiometry-dependent color tunability

Abstract

Two 3D porous terbium(III) mucicate frameworks, {[Tb₂(Mu^2-)3(H₂O)₂]·4H₂O}_n (1) and {[Tb(Mu^2–)(Ox^2–)_0.5(H₂O)]·H₂O}_n (2), have been synthesized under hydrothermal conditions by changing the pH of the reaction medium. Isostructural europium(III) and seven mixed terbium(III)–europium(III) mucicates were synthesized by doping different percentages of Eu^III under similar reaction conditions and unveiling different emission colors ranging from green to red under the same wavelength. Both dehydrated Tb^III metal–organic frameworks exhibit selective H₂O vapor sorption over other solvent molecules (MeOH, MeCN, and EtOH) of less polarity and bigger size and have been correlated to the highly hydrophilic pore surfaces decorated with −OH groups and O atoms from the carboxyl groups of mucicate.