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Synthesis and characterization of group IVB metallocene materials derived from hematoporphyrin IX
Title
Synthesis and characterization of group IVB metallocene materials derived from hematoporphyrin IX.
Creator
Rivalta, Alberto Enrico., Florida Atlantic University, Carraher, Charles E., Haky, Jerome E.
Abstract/Description
New organometallic containing materials were synthesized by the reaction of Group IVB metallocene dichlorides of the form Cp2MCl2 where M = Ti, Ar, and Hf with Hematoporphyrin IX using the interfacial condensation polymerization technique. The structural characterization was accomplished using infrared and mass spectroscopy and elemental analysis. The results obtained from these techniques showed the presence of the metal ester and ether bonding as evidence that the reaction occurred. The...
Show moreNew organometallic containing materials were synthesized by the reaction of Group IVB metallocene dichlorides of the form Cp2MCl2 where M = Ti, Ar, and Hf with Hematoporphyrin IX using the interfacial condensation polymerization technique. The structural characterization was accomplished using infrared and mass spectroscopy and elemental analysis. The results obtained from these techniques showed the presence of the metal ester and ether bonding as evidence that the reaction occurred. The product derived from titanocene dichloride, 12-A, exhibited growth inhibition characteristics towards the Candid albicans and Staphylococcus aureus microorganisms. From the preliminary metal adsorption studies it was shown that this product also bound nickel ions.
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Date Issued
1993
PURL
http://purl.flvc.org/fcla/dt/14940
Subject Headings
Organometallic chemistry, Porphyrins, Hematoporphyrin, Metallocenes
Format
Document (PDF)
New stereoselective reactions to form amido alkyl c-n and vinyl triflate c-o bonds via carbocation intermediates & ultrafast silicon fluorination methodologies for applications in pet imaging
Title
New stereoselective reactions to form amido alkyl c-n and vinyl triflate c-o bonds via carbocation intermediates & ultrafast silicon fluorination methodologies for applications in pet imaging.
Creator
Alhuniti, Mohammed, Lepore, Salvatore D., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
We report here the development of a Lewis acid catalyzed method for the dehydrative coupling of cyclic alcohols and nitriles to form amides with retention of configuration. By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction) usually affords racemic product. The present reaction was accomplished by first converting alcohol starting materials to their corresponding chlorosulfites in situ. Even after an extensive search, only copper (II) salts were able to...
Show moreWe report here the development of a Lewis acid catalyzed method for the dehydrative coupling of cyclic alcohols and nitriles to form amides with retention of configuration. By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction) usually affords racemic product. The present reaction was accomplished by first converting alcohol starting materials to their corresponding chlorosulfites in situ. Even after an extensive search, only copper (II) salts were able to produce the desired conversion of these chlorosulfites to amides though with low catalytic turnover. Improving the turnover without deteriorating the stereochemical outcome was eventually accomplished by a careful selection of the reagent addition sequence and through the removal of gaseous byproducts. This Ritter-like coupling reaction proceeds in good yields with secondary cyclic alcohols under mild conditions. The stereochemical outcome likely due to fast nucleophilic capture of a non-planar carbocations (hyperconjomers) stabilized by ring hyperconjugation.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004262
Subject Headings
Intermediates (Chemistry), Nuclear medicine, Organometallic chemistry, Physical organic chemistry, Reaction mechanisms (Chemistry), Tomography, Emission
Format
Document (PDF)
Studies towards a catalytic asymmetric isomerization of manganese complexed alkynes to allenes using chiral bases
Title
Studies towards a catalytic asymmetric isomerization of manganese complexed alkynes to allenes using chiral bases.
Creator
He, Chang., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
The conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordination followed by a base-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. Chiral amidine and chiral DBU derivatives were synthesized to carry out the isomerization enantioselectively. We employed HPLC equipped with a chiral column to determine the enantiomeric excess. We also proved that the mechanism of that the manganese-coordinated alkyne/allene rearrangement...
Show moreThe conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordination followed by a base-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. Chiral amidine and chiral DBU derivatives were synthesized to carry out the isomerization enantioselectively. We employed HPLC equipped with a chiral column to determine the enantiomeric excess. We also proved that the mechanism of that the manganese-coordinated alkyne/allene rearrangement reaction involved an intermediate cumenolate. It was also confirmed that amine base with pKa lower than that of DBU (pKa = 13.6) would not carry out the isomerization. Alkoxy base were also used in isomerization and the mechanism was also investigated.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/192983
Subject Headings
Enzyme kinetics, Organometallic compounds, Synthesis, Asymmetric synthesis, Methathesis (Chemistry), Carbonyl compounds, Synthesis
Format
Document (PDF)
Hemisynthesis and Characterization of Cyclopheophorbides
Title
Hemisynthesis and Characterization of Cyclopheophorbides.
Creator
Mortezaei-Rad, Mitra, Florida Atlantic University, Louda, J. William, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description
Cyclopheophorbides absorb light at higher wavelengths (> 670 run) as compared to their precursor pyropheophorbides ( ~ 666 run) and are strong antioxidants. Therefore they could potentially be used as photosensitizers in photodynamic therapy, although this study does not focus on the pharmacology aspect of this class of compounds. The overall goal of this study was to hemisynthesize, purify and characterize certain cyclopheophorbides from both chlorophyll a and b families. The known...
Show moreCyclopheophorbides absorb light at higher wavelengths (> 670 run) as compared to their precursor pyropheophorbides ( ~ 666 run) and are strong antioxidants. Therefore they could potentially be used as photosensitizers in photodynamic therapy, although this study does not focus on the pharmacology aspect of this class of compounds. The overall goal of this study was to hemisynthesize, purify and characterize certain cyclopheophorbides from both chlorophyll a and b families. The known hemisynthesis of 13^2,17^3-cyclopheophorbide a enol was repeated. A major success in the purification process was achieved by utilizing polystyrene divinylbenzene (PS-DVB a.k .a. PRP-1 TM) as the stationary phase in reversed phase flash chromatography. Altering (TMS)2-NNa with (TMS)2-NLi was found to increase yields. 13^2,17^3 -mesocyclopheophorbide a enol was successfully hemisynthesized as a novel compound. Methyl-3-devinyl-3-[1-hexyloxy]ethyl pyropheophorbide a (HPPH-ME), was prepared, purified and molecular characteri zation on the compound was performed. Hemisynthesis ofHPPH-CYCLO from HPPH-ME was attempted, but was unsuccessful. Zinc and copper pyropheophorbide a methyl esters were prepared with the intent of forming of zinc and copper CYCLO. Hemisynthesis of corresponding metalloCYCLO from both insertion of the metal inside the CYCLO core and cyclizations of metal derivatives of pyropheophorbide a methyl ester were unsuccessful. Chlorophyll b was successfully extracted from green algae Chiarella and purified in mg lots (100%) utilizing RP-LPLC and with a binary solvent gradient program. Pheophorbide b methyl ester and pyropheophorbide b methyl ester were made and characterized. Hemisynthesis of CYCLO-b was unsuccessful likely due to the altered reactivity of pyropheophorbide b (vs. -a) methyl ester. To reduce the reactivity, reduction of formyl group of pyropheophorbide b methyl ester with NaBH4 was performed. Still, formation of a CYCLO derivative was not achieved. Chromatographic purification, mass and NMR characterization of CYCLO, mesoCYCLO, HPPH-ME and all precursor compounds are reported. 2D NMR of most of these compounds are reported here for the first time.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00000872
Subject Headings
High performance liquid chromatography, Organometallic chemistry, Organic compounds--Spectra, Organophosphorus compounds
Format
Document (PDF)