Charge transfer in polymeric systems.
Item
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Title
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Charge transfer in polymeric systems.
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Identifier
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AAI9009728
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identifier
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9009728
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Creator
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DiBerardino, Thomas.
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Contributor
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Adviser: Nan-Loh Yang
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Date
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1989
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Polymer | Chemistry, Physical
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Abstract
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Charge transfer complexes of polymeric donors having pendent pyridine rings and low molecular weight acceptors were studied. Electronic spectroscopy was used to investigate high molecular weight (HMW), low molecular weight (LMW) and isotactic ({dollar}i{dollar}-) poly(2-vinylpyridine) (P2VP) and pyridine donors with iodine in solvents of varying dielectric constants and abilities to form hydrogen bonds. Electronic absorption parameters and formation constants (K), were analyzed and mechanisms for the different behaviors developed.;Charge transfer complexes formed between {dollar}i{dollar}-P2VP and tetracyanoethylene (TCNE) were observed in liquid and solid states by NMR spectroscopy. In the liquid state, K and the change in chemical shift upon formation of the pure complex ({dollar}\Delta\sb0{dollar}) were obtained and compared to the 2-ethylpyridine (2EP) donor system. The order for {dollar}\Delta\sb0{dollar} was different in the two systems. {dollar}i{dollar}-P2VP yielded a K of 21 kg/mole and was concentration dependent. Unique behavior of H{dollar}\sb3{dollar} and H{dollar}\sb6{dollar} of the polymer supported a proposed topographic model for the complex. K for 2EP of 6 Kg/mole was found to be dependent on additional unspecific shielding and independent of donor concentration. In the solid state, {dollar}i{dollar}-P2VP and P4VP complexed with TCNE were studied. The extent of electron transfer estimated from infrared data verified large shifts of TCNE. TCNE carbons were studied as a function of contact time and in delayed decoupling experiments which further confirm the proposal model.;The free radicals formed by P2VP, P4VP and poly(4-vinglpyrimidine) (P4VPm) complexed with TCNE were studied in the liquid and solid states. Two radicals were detected in the solid while only the TCNE radical was observed in solution. Spin density for the P4VP system reached a maximum at 2:1 donor ring to acceptor ratio while all P2VP polymers reached a maximum at 4:1.;Reactions giving improved yield of intermediaries in the formation of P4VPm were developed. Dehydration of a primary alcohol intermediate to give high yields of the vinyl product was arrived at. Proposed mechanistic schemes for these reactions explain previous low yields.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
