Nuclear magnetic resonance investigation of magnetic and electronic properties of intermediate spin ferrous porphyrin complexes

Journal Article · Wed May 25 04:00:00 EDT 1977 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00453a022· OSTI ID:7104382

Goff, H; La Mar, G N; Reed, C A

The proton NMR spectra of unligated ferrous porphyrins, proposed to exist in the intermediate S = 1 spin state, have been recorded and analyzed. The dominant dipolar shifts for the phenyl protons in tetraphenylporphinatoiron(II) result in a quantitative measure of the axial magnetic anisotropy, which, together with the average moment, yield ..mu../sub perpendicular/ = 4.9 ..mu../sub B/ and ..mu../sub parallels/ = 3.2 ..mu../sub B/. The resultant contact shifts for pyrrole substituents reflect extensive ..pi.. spin transfer, which originates solely from porphyrin ..-->.. iron change transfer. The contact shift pattern indicates that d/sub x/sup 2/y/sup 2// is unoccupied, confirming the spin-triplet ground state. The large ..pi.. contact shifts require unpaired spins in d/sub xz/,d/sub yz/, and strongly support the ground state configuration, (d/sub xy/)/sup 2/(d/sub z/sup 2//)/sup 2/(d/sub xz/,d/sub yz/)/sup 2/, which has been previously shown to be the one favored by the average moment and Moessbauer data.

• Research Organization: Univ. of California, Davis
• OSTI ID: 7104382
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 99:11; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
CARBOXYLIC ACIDS
COMPLEXES
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INTERMEDIATE STRUCTURE
IRON COMPLEXES
MAGNETIC PROPERTIES
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PORPHYRINS
RESONANCE
TRANSITION ELEMENT COMPLEXES