TitleSynthesis and phtoluminescence [sic] study of microporous metal organic frameworks (MMOFs) for sensing and detection of nitroexplosives and aromatic compounds
NamePramanik, Sanhita (author), Li, Jing (chair), Brennan, John (internal member), Warmuth, Ralf (internal member), Pan, Long (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectChemistry and Chemical Biology,
DescriptionDue to the increased terrorist activity worldwide and the use of modern bombs in those attacks, the development of a new method capable of rapidly and cost-efficiently detecting trace vapor of explosives is highly desirable. Chemical explosives composed of a diverse group of compounds, including nitroaromatics, nitramines, nitrate esters as well as some inorganic/organic nitrates and peroxides. Current methodologies include use of well trained dogs and sophisticated instrumentation such as gas chromatography coupled with a mass spectrometer, nuclear quadruple resonance, ionization mass spectrometry (IMS). These methods are highly sensitive and selective, but often expensive, not always easily accessible, and require intense training for operation. As a complementary method, chemical sensors can provide new ways to the rapid detection of ultra trace explosives, and can be easily incorporated into inexpensive and portable microelectronic devices. Fluorescence based sensors utilizing conjugated polymers have attracted enormous attention in the recent years for their excellent performance. In this thesis, a systematic study was performed in a series of luminescent MMOFs and their behavior upon exposure to the vapor of different analytes. For example, [Zn2(oba)2(bpy)]∙DMA, one of the MMOFs made of paddle-wheel SBU, selectively responds to nitroaromatics (with electron-withdrawing groups) and other aromatic compounds, like benzene, toluene (with electron-donating groups) via fluorescent quenching and enhancement respectively. The study also shows that nitro-containing non-aromatic analytes (nitroaliphatics) make negligible effect on the fluorescence of [Zn2(oba)2(bpy)]∙DMA . The results demonstrate the exceptional ability of this particular MMOF to selectively detect explosives of different types (e.g. aromatic DNT vs. non-aromatic or aliphatic DMNB). Another series of highly luminescent MMOFs made of the same metal center (Zn) and similar ligands (bpdc, bpy, 2,2′dmbpy and bpe) but different structures have also been investigated. Photoluminescence studies show that the guest-free samples of these compounds also exhibit quenching or enhancement phenomena, when exposed to the vapors of two different types of analyte molecules having electron rich and electron deficient functional groups. The origin of such effect can be well understood and explained based on molecular orbital and band structure calculations, as well as the comparison of their redox potentials. In addition, synthesis and characterization of some new MMOFs, composed of V-shaped dicarboxylic acid and selected diamine ligands are briefly discussed. Clearly, ligands play an important role in the crystal structure formation as well as pore characteristics of the resultant MMOFs.
NoteIncludes bibliographical references
Noteby Sanhita Pramanik
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.