Porphyrins-cyclodextrin. 2. Dissociation, reduction, and proton relaxivity of an iron(III) porphyrin. mu. -oxo dimer in cyclodextrin solutions. [Pulsed gamma radiation]

Journal Article · Thu Jun 13 04:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100165a014· OSTI ID:5889396

Mosseri, S; Mialocq, J C; Perly, B ^[1]; Hambright, P ^[2]

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1. CEA-CEN Saclay, Gif-sur-Yvette (France)
2. Howard Univ., Washington, DC (United States)

Spectrophotometric evidence for the dissociation of an Fe(III) porphyrin {mu}-oxo dimer induced by porphyrin-cyclodextrin complexation in aqueous solution is reported. Depending on the pH, the monomer may be in a diaquo monohydroxo or diaquo dihydroxo form with pK values of 6.4 or 8.5, respectively. In the absence of {beta}-cyclodextrin ({beta}-CD), the {mu}-oxo dimer exists as mono- or dihydroxo species with a pK of 11.7. {gamma}- and pulse radiolysis techniques are used to study the Fe(III)/Fe(II) reduction. Fe{sup III}TSPP(H{sub 2}O){sub 2} (TSPP is tetrakis(4-sulfonatophenyl)porphyrin) is reduced by hydrated electrons and CH{sub 2}OH{sup {sm bullet}} radicals into Fe{sup II}TSPP(H{sub 2}O){sub 2} whereas Fe{sup III}TSPP(OH{sup {minus}}){sub 2} and (H{sub 2}O)FeTSPP-O-FeTSPP(OH{sup {minus}}) are both reduced to the monohydroxo Fe{sup II}TSPP(H{sub 2}O)(OH{sup {minus}}) monomer. The Fe{sup II}-O-Fe{sup II} dimer may be formed in strongly alkaline solution. Measurements of the proton (NMR) relaxivity values of this Fe(III) porphyrin in the absence and in the presence of {beta}-CD indicate the possibility of using Fe{sup III}TSPP in conjunction with {beta}-CD as a paramagnetic contrast agent for in vivo imaging of tumors and tissue.

• OSTI ID: 5889396
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:12; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400600* -- Radiation Chemistry
ABSORPTION SPECTROSCOPY
AQUEOUS SOLUTIONS
BEAMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOHYDRATES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
COBALT 60
COBALT ISOTOPES
COMPLEXES
DATA
DECOMPOSITION
DEXTRIN
DIMERS
DISPERSIONS
DISSOCIATION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRONS
ELEMENTARY PARTICLES
EXPERIMENTAL DATA
FERMIONS
GAMMA RADIATION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDRATION
IN VIVO
INFORMATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
IRON COMPLEXES
IRON COMPOUNDS
IRON OXIDES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEPTON BEAMS
LEPTONS
MAGNETIC RESONANCE
MAGNETISM
MINUTES LIVING RADIOISOTOPES
MIXTURES
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PARAMAGNETISM
PARTICLE BEAMS
PH VALUE
PHYSICAL PROPERTIES
POLYSACCHARIDES
PORPHYRINS
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOISOTOPES
RADIOLYSIS
REDUCTION
RESONANCE
SACCHARIDES
SOLUTIONS
SOLVATED ELECTRONS
SOLVATION
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
VISIBLE SPECTRA
YEARS LIVING RADIOISOT