Open AccessProton Nuclear‐Magnetic‐Resonance Study of Low‐Spin Ferriprotoporphyrin(IX) Dimethyl Ester
Author(s) -
GOLDAMMER Eberhard,
ZORN Herbert,
DANIELS Alfred
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb02300.x
Subject(s) - chemistry , pyridine , relaxation (psychology) , proton , chemical shift , nuclear magnetic resonance , spin (aerodynamics) , proton nmr , spin–lattice relaxation , zeeman effect , organic chemistry , magnetic field , physics , thermodynamics , psychology , social psychology , quantum mechanics
Proton nuclear magnetic resonance shifts, spin‐lattice and spin‐spin relaxation times have been measured of low‐spin bis‐pyridine ferriprotoporphyrin(IX) dimethyl ester in chloroform. From the relaxation behavior the hyperfine coupling constant has been obtained and the contact term of the chemical shift was calculated. Deviations between measured and calculated chemical shifts may be attributed to second‐order Zeeman interactions. The geometry of pyridine coordinated to the fifth and sixth position of ferriprotoporphyrin(IX) dimethyl ester was estimated from measured relaxation rates. From the non‐exponential decay of the M z magnetization a mean lifetime of τ b = 50 ms for pyridine attached to low‐spin ferriprotoporphyrin(IX) dimethyl ester was found at 253 K.