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M.Sc. Anwar Abo-Amer :
Dissertation angenommen durch: Universität Duisburg-Essen, Campus Duisburg, Fachbereich Chemie, 2005-01-26
BetreuerIn: Prof. Dr. Hermann-Josef Frohn , Universität Duisburg-Essen, Campus Duisburg, Fachbereich Chemie
GutachterIn: Prof. Dr. Hermann-Josef Frohn , Universität Duisburg-Essen, Campus Duisburg, Fachbereich Chemie GutachterIn: Prof. Dr. Günter Geismar , Universität Duisburg-Essen, Campus Duisburg, Fachbereich Chemie
Schlüsselwörter in Englisch: Taft´s method, inductive and
resonance parameters, reactivities of perfluoroalkenyl(aryl)iodonium
sal, reactivities of monofluoro(difluoroiodo)benzenes, NMR
spectroscopy, Alkenyl(aryl)iodonium salts, thermal stability,
Diaryliodonium salts, organoiodofluorides, iodine pentafluoride,
hypervalent compounds
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Abstrakt in Englisch
This dissertation offers at least four new contributions to chemical
science: (1) A new method of generation iodofluorides and
organoiodofluorides, in which a simple, general and industrial
applicable route to I-F compound was developed. This method is suitable
for the synthesis of IF5, organoiodine(III) fluorides, and
-(V)fluorides. The convenient method is characterised by an
oxygen-fluorine substitution process using anhydrous HF (aHF) or
aqueous HF in a two phase system. (2) The first synthesis of
perfluoroalkenyl(aryl)iodonium tetrafluoroborate salts is reported. The
salts result from the reaction of (difluoroiodo)arenes (ArIF2)
generally with organodifluorboranes to yield the corresponding
organo(aryl)iodonium tetrafluoroborates in good yields and high purity.
The iodonium salts were investigated spectroscopically and
structurally. (3) Key reactivities of monofluoro(difluoroiodo)benzenes
are investigated. The reactions of (difluoroiodo)arenes (Ar = o-, m-,
p-C6H4F) with n [N(CH3)4]F (n = 0.5, 1, 2, 3), CsF (n = 1, 2),
2,2´-bipyridine, and different kind of alcohols (CH3OH, CH3CH2OH and
CF3CH2OH) and protonic acids (CF3CO2H, HF) were examined. The solid
structure of ArIF2 (Ar = o-, p-C6H4F) was investigated which show
strong intermolecular contacts between the positively charged iodine
centre and negatively charged fluorine atoms of the IF2 group of
neighbour molecules. Zigzag arrangements result in case of the para and
ortho isomers. (4) Introduction concerning the reactivity of
perfluoroalkenyl(aryl)iodonium tetrafluoroborate salts were performed.
The reactions of perfluorovinyl(aryl)iodonium tetrafluoroborate salts
with [N(CH3)4]F in dichloromethane show that the metathesis of the
tetrafluoroborate anion by fluoride was accompanied by the spontaneous
decomposition even at low temperature. The reaction of
[trans-CF3CF=CF(aryl)I][BF4] with weak but oxidisable Lewis bases such
as (p-C6H4F)3As or (p-C6H4F)3P emphasise the preparative potential of
perfluoroalkenyl-(aryl)iodonium salts to enable the electrophilic
alkenylation of nucleophiles. In the present case
[trans-CF3CF=CF(p-C6H4F)3As][BF4] and [trans-CF3CF=CF(p-C6H4F)3P][BF4]
were formed in a mixture of by-products. In the crystal structure of
the alkenyl(aryl)iodonium tetrafluoroborate salt a pronounced cation
anion interaction was found which lead to a three-dimensional network.
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