In situ FTIR and UV-visible spectroelectrochemical studies of iron nitrosyl porphyrins in nonaqueous media

Journal Article · Wed Dec 28 04:00:00 EST 1988 · Inorganic Chemistry; (USA)

DOI:https://doi.org/10.1021/ic00299a009· OSTI ID:5439366

Mu, X H; Kadish, K M ^[1]

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1. Univ. of Houston, TX (USA)

The techniques of in situ FTIR and UV-visible spectroelectrochemistry were combined with microvoltammetry in order to elucidate the prevailing mechanism for electrooxidation of (P)Fe(NO), where P is the dianion of tetraphenylporphyrin (TPP), meso-tetrakis(2,4,6-trimethylphenyl)porphyrin (TMP), or octaethylporphurin (OEP). Each metalloporphyrin undergoes three reversible oxidations at a Pt microelectrode of 25-{mu}m diameter. These oxidations were examined with respect to the site of electron transfer and to the fate of the NO group on the time scales of thin-layer cyclic voltammetry and bulk controlled-potential electrolysis. The NO group remains coordinated to the Fe(III) center after electrooxidation of (P)Fe(NO) and a 166-187-cm{sup {minus}1} shift in NO vibration is observed upon going from (P)Fe(NO) to ((P)Fe(NO)){sup +} in CH{sub 2}Cl{sub 2}, 0.1 M TMAP. However, the bound NO ligand dissociates from ((P)Fe(NO)){sup 2+}, which is electrogenerated at more positive potentials. The effects of bound halide ion or neutral ligand coordination on {gamma}{sub NO} of ((P)Fe(NO)){sup +} were also examined. {gamma}{sub NO} of (P)Fe(NO)X, where X = Cl{sup {minus}}, Br{sup {minus}}, or I{sup {minus}}, is linearly related to the ionization potential of HX while {gamma}{sub NO} of ((P)Fe(NO)(S)){sup +} (where S is a bound solvent molecule) is linearly correlated with the Gutmann solvent number (DN) of the trans-lighted solvent molecule in bulk CH{sub 2}Cl{sub 2}.

• OSTI ID: 5439366
• Journal Information: Inorganic Chemistry; (USA), Journal Name: Inorganic Chemistry; (USA) Vol. 27:26; ISSN 0020-1669; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHEMICAL STATE
ELECTROLYSIS
ELECTROMAGNETIC RADIATION
ELECTRON TRANSFER
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFRARED RADIATION
INFRARED SPECTRA
INFRARED THERMOGRAPHY
IONIZATION POTENTIAL
IRON COMPOUNDS
IRON NITRATES
IRON NITRIDES
LYSIS
MEASURING METHODS
NITRATES
NITRIDES
NITROGEN COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PNICTIDES
PORPHYRINS
RADIATIONS
REDOX REACTIONS
REDUCTION
SPECTRA
SPECTROSCOPY
THERMOGRAPHY
TRANSITION ELEMENT COMPOUNDS
ULTRAVIOLET SPECTRA
VOLTAMETRY