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

Abstract

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.·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.

Exuberant Immobilization of Urease on an Inorganic SiO2 Support Enhances the Enzymatic Activities by 3-fold for Perennial Utilization

“…On the other hand, retention of amorphous identity (a single broad peak at 22.26° in XRD spectrum of {SiO 2 }@urease; Figure a) clearly indicates that all sorts of chemical reactions for surface modification occur at the surface of SG only keeping intact the core identity of the SG unit cell, {Si­(OSi) 4 (H 2 O) 0.16 } n (as per Scheme ). − The full XPS survey spectrum (Figure b) and high resolution peak differentiation and imitating spectrum for different elements (Figure c–e) of the as-prepared material were obtained by employing 1486.7 eV radiation as line source. These were closely analyzed for better understanding of elemental composition and formulation of the synthesized material.…”

“…Our group, during the synthesis of a class of chromatographic extractors by immobilizing ligands on SG, − very efficiently introduced the nitrobenzoyl fragment on the SG surface (to compound Z of Scheme ) through an instantaneous reaction using dimethyldichlorosilane (DMDCS) as a second generation silane coupling reagent. It is successfully able to replace the time-consuming and stringent (refluxing ≥90–120 h) first and second step of the “Weetall reaction” by an instantaneous one pot single step straightforward methodology (Scheme ).…”

Fluorescent Resin-Assisted Extraction for Selective Separation and Preconcentration of Mercury(II) and Its Online Detection

“…As an outcome of our previous work relating to instantaneous attachment of metal chelators, viz., Xylenol Orange, PAN to SG via a new silane coupling agent (dimethyldichlorosilane) 51,52 forming immobilized chelate phases encourages the present authors to develop EBTimmobilized-SG SPE material (EBT@R-{SiO 2 } n ; where R stands for p-NN−C 6 H 4 −NH−SiCl 2 −O−) for selective sample cleanup of mercury(II) from its congeners. Dimethyldichlorosilane simultaneously couples SG and p-nitroaniline and quantitatively produces a stable nitro compound,…”

Chemically Bonded Pepsin via Its Inert Center to Diazo Functionalized Silica Gel through Multipoint Attachment Mode: A Way of Restoring Biocatalytic Sustainability over “Wider pH” Range

“…A thorough investigation was made to confirm the amino-acid sequence of pepsin. 129 It comprises 327 amino-acid residues in its single polypeptide chain, among which it holds 15 tyrosine residues residing at 14,44,75,86,113,114,125,154,174,175,189,268,275,310, and 311th position in its molecular sequence. 65 All the tyrosine residues comprising phenolic rings are well apart from the enzyme's active site and entitled to effective participation in the diazo coupling.…”

“…where, four −N + �N on the functionalized SG makes four diazo covalent linkages at Oposition of the tyrosine's phenolic ring. In its molecular networks, pepsin contains 15 Tyr residues distributed almost equally in two homologous domains; eight are placed at 14,44,75,86,113,114,125, and 154th in the N-terminal (residues 1−172), while seven are at 174, 175, 189, 268, 275, 310, and 311th in C-terminal (residues 173− 327). Among these 15 Tyr residues, four Tyr from two domains, contributing equally, are well entitled to diazo linkages with the functionalized SG, as may be shown in Scheme 4.…”