Facile Synthesis of a Luminescent Material, PAN@{SiO₂}_n, Having a Simultaneous Binding Capacity of High and Low Oxidation States: HOMO and LUMO, Quantum-mechanical Descriptor of Break-through Capacity

抄録

A time-cost effective, chemically stable mesoporous resin (FSG-PAN), simultaneous binder of two different metal centers (both high (Cd(II)) and low (Tl(I)) oxidation states), has been synthesized by immobilizing azo-dye (1-(2-pyridylazo)-2-napthol: PAN) on functionalized silica gel (FSG). Its corresponding synthesized nano material possesses good luminescent properties, and has been utilized in fluoride sensing at trace levels (1.8 × 10⁻⁶ – 7.2 × 10⁻⁶ M). The composition ({Si[OSi]_p=4[H₂O]_x=0.81}₁₂[–Si(CH₃)₂–NH–C₆H₄–N=N–PAN]₄.·51H₂O) and structure (tetrahedral) have been well assessed. Under the optimum extraction conditions, the soft extractor (η_FSG-PAN = 1.31 eV), FSG-PAN quantitatively extracts the soft metal centers Cd(II), followed by Tl(I) at its respective HOMO and LUMO by soft-soft interactions. The extractor possesses a high Brunauer–Emmett–Teller (BET) surface area (SA_BET) (374 m² g⁻¹), high preconcentration factor (PF, 192), selective pore size and two kinds of break-through capacity (BTC_HOMO, 945 μmol g⁻¹; BTC_LUMO, 120 μmol g⁻¹). BTC is spelled out as a function of the electron density over the ligand binding site as analyzed from a DFT calculation.