Iron-hydroxide stretching resonance Raman bands of a water-soluble sterically hindered porphyrin
- Princeton Univ., NJ (USA)
- National Taiwan Univ., Taipei (Taiwan)
Resonance Raman (RR) spectroscopy capable of providing much information about the strength of Fe-ligand bonds in heme proteins has been applied to the study of the Fe-OH bond. The first observations and assignment of nu(Fe-OH) and {nu}{sub sym}(Fe-(OH){sub 2}) stretching bonds are reported herein. It has also been demonstrated that the bis(hydroxo)complex constitutes an S=5/2, S=1/2 spin equilibrium that is reminiscent of alkaline met myoglobin. The RR, NMR, and ESR data provide consistent and compelling evidence for the existence of primarily three coordination states of the (tetrakis(2-N-methylpyridiniumyl)-porphinato) iron (III), Fe(T(2-N-Me)PyP){sup 5+} (aq) ion in solutions of varying pH. At low pH values, a high-spin aquo complex exists; while at intermediate pH values, a high-spin 5-coordinate mono(hydroxo) complex was found. A high-spin/low-spin equilibrium of bis(hydroxide) species was noted at high pH values. 23 refs., 4 figs.
- OSTI ID:
- 6286514
- Journal Information:
- Inorganic Chemistry; (USA), Journal Name: Inorganic Chemistry; (USA) Vol. 29:16; ISSN 0020-1669; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKANES
AQUEOUS SOLUTIONS
AZINES
BOND LENGTHS
CARBOXYLIC ACIDS
COMPLEXES
DATA
DIMENSIONS
DISPERSIONS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
HEME
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROXY COMPOUNDS
INFORMATION
IRON COMPLEXES
ISOTOPES
LENGTH
LIGHT NUCLEI
MIXTURES
NMR SPECTRA
NUCLEI
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN 18
OXYGEN ISOTOPES
PH VALUE
PIGMENTS
PORPHYRINS
PROTEINS
PYRIDINE
PYRIDINES
SOLUTIONS
SPECTRA
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES