Functionalized Mesoporous Silica, MCM-41, and their Application in Environmental Remediation of Selenium, Cadmium, and for Zinc Detection by Fluorescence and Synthesis and Photolysis Studies of Cobalt Analogues of Roussin's Red Salt Esters.

摘要

Within the past two decades ordered mesoporous silica materials have seen tremendous growth in its innovation and creativity with respect to its various applications. One class of materials, MCM-41, with large surface areas and pore size make them attractive as adsorbent materials. In addition, surface hydroxyl groups can be modified with organic functionalities. The pore volume after grafting of these groups is still large enough to carry out chemical reactions in the internal surface. It is this quality that has prompted us to study these materials and explore the covalent strategies of attaching new functional groups on the surface of the substrate, and subsequently test their abilities to: (a) Remove oxyanions of selenium from aqueous systems (b) Removal of cadmium, a heavy metal pollutant, in aqueous media, and (c) Detect zinc by fluorescence in order to develop nanoporous bio-sensors.;Cobalt analogues of the Roussin's red salt esters, Co2(NO) 4(micro-SR)2, where R = t-butyl, butyl, ethyl, phenyl, 1, 3-propanedithiol, and t-butyl selenol derivative, Co2(NO)4(micro-SeR)2, have been prepared by the reaction of organic thiol or selenol compounds with the readily prepared [Co(NO)2Cl]2. The compounds are unstable to light and decompose in ca. one week even in the dark at -78°C. Frozen matrix photolysis of Co2(NO)4(micro-S- t-butyl)2, Co2(NO)4(micro-S-Ethy1) 2, and Co2(NO)4(micro-Se-t-butyl) 2 are examined. The IR spectra suggest a C2v symmetry for the compounds with the possibility of a folded Co2S2 rhombus about the S-S axis. Linkage isomerism of the nitrosyl ligand is observed in all the complexes. The results show bands characteristic of isonitrosyl and/or side-on linkage isomers.