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.

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 (ηFSG-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 (SABET) (374 m(2) g(-1)), high preconcentration factor (PF, 192), selective pore size and two kinds of break-through capacity (BTCHOMO, 945 μmol g(-1); BTCLUMO, 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.