Raman spectrosopic characterization of isomers of copper and zinc N-phenylprotoporphyrin IX dimethyl ester

Journal Article · Wed Jul 07 00:00:00 EDT 1993 · Inorganic Chemistry; (United States)

OSTI ID:5838795

Swanson, B A; Ortiz de Montellano, P R ^[1]; Hsu, P; Ondrias, M R; Sparks, L D; Shelnutt, J A ^[2]

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1. Univ. of California, San Francisco (United States)
2. Univ. of New Mexico, Albuquerque (United States)

The reaction of certain heme-containing proteins with phenylhydrazine results in N-phenylprotoporphyrin formation. N-substituted porphyrins are known to inhibit ferrochelatase and to be formed in the inactivation of hepatic cytochrome P[sub 450] by various agents. These molecules therefore play an important role in understanding the biological function of these enzymes. The authors have used molecular modeling in conjunction with resonance Raman and UV-visible absorption spectroscopies to investigate the structure of the four distal regioisomers of N-phenylprotoporphyrin IX dimethyl ester (NPhPPDME) metal derivatives. Regardless of which pyrrole ring (A, B, C, or D) bears the N-phenyl substituent, a novel distortion from planarity of the protoporphyrin macrocyclic results from addition of the phenyl group. The molecular mechanics calculations for various isomers and conformers of copper(II) N-phenylprotoporphyrin IX predict structures similar to the structure reported for zinc N-phenyltetraphenylporphyrin, with the major distortion from planarity occurring for the N-substituted pyrrole ring. Although the four isomers of CuNPhPPDME are all similar when contrasted with CuPPDME, closer examination of the vibrational structure allowed the isomers to be separated into two groups. Differences among pairs of isomers are apparent primarily in the vinyl vibrational modes and vinyl-sensitive porphyrin modes. Even more subtle spectral differences distinguish all of the isomers. The authors present arguments suggesting that the spectral characteristics are the result of electronic rather than kinematic effects.

• OSTI ID: 5838795
• Journal Information: Inorganic Chemistry; (United States), Vol. 32:14; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COPPER COMPLEXES
RAMAN SPECTROSCOPY
ZINC COMPLEXES
ESTERS
ISOMERS
MATHEMATICAL MODELS
MOLECULAR STRUCTURE
PROTOPORPHYRINS
VIBRATIONAL STATES
CARBOXYLIC ACIDS
COMPLEXES
ENERGY LEVELS
EXCITED STATES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LASER SPECTROSCOPY
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PIGMENTS
PORPHYRINS
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties