SYNTHESIS AND REACTIONS OF PENTAPHENYLETHYL CARBANION AND SYNTHESES OF ETA(6)-CHROMIUMTRICARBONYL PENTAPHENYLETHANES.
Item
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Title
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SYNTHESIS AND REACTIONS OF PENTAPHENYLETHYL CARBANION AND SYNTHESES OF ETA(6)-CHROMIUMTRICARBONYL PENTAPHENYLETHANES.
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Identifier
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AAI8713779
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identifier
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8713779
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Creator
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MISRA, BIJAYA.
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Contributor
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herman Zierger
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Date
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1987
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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, Organic
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Abstract
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The synthesis of pentaphenylethyl carbanion by deprotonation of pentaphenylethane with KOBu('t)/BuLi at -78(DEGREES)C has been achieved. Chemical Ionisation mass spectrometric analysis of the deuteriopentaphenylethane shows 80% of monodeuteration at the benzylic carbon and 10% of dideuteration at both benzylic and aromatic carbons. Reactions of the anion with electrophiles such as MeI, CO, TMCS and DMS are described. It appears that pentaphenylethyl carbanion undergoes a single electron oxidation to a pentaphenylethyl radical whose limited stability results in fragmented derivatives such as triphenylmethanol and benzophenones.;Two chromiumtricarbonyl coordinated pentaphenylethanes have been synthesised via coupling reactions. Furthermore a number of Arene-Cr(CO)(,3) complexes have been prepared utilizing two different methods in good to excellent yields. Single crystal X-ray structure analyses of the PPE-CTC complexes have been completed; the ethane bond distance in C(1) and C(2) complexes were found to be 1.615 (+OR-) 0.007 (ANGSTROM) and 1.620 (+OR-) 0.006 (ANGSTROM). The chromiumtricarbonyl unit was found in a staggered orientation with respect to the ring carbons in both complexes. A near staggered conformation of the phenyl rings around the ethane bond have been observed.;A carbon-13 NMR study of pentaphenylethyl carbanion shows no evidence for a thermal decomposition of the anion to a trityllithium. The anions of pentaphenylethane-CTC complexes have been synthesised at room temperature from their hydrocarbon with KOBu('t) in DMSO. Carbon-13 NMR of the anion have shown the carbonyl resonances near 241 ppm, a deshielding of 8.2 to 8.4 ppm with respect to that of the hydrocarbons. The Benzylic carbon resonance in PPE(C2)-CTC anion was observed at 105.8 ppm. For PPE(C1)-CTC anion a (eta)('5)-chromiumtricarbonyl structure is proposed.
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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.
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Program
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Chemistry
