THERMOMAGNETIC ANALYSIS OF HEMIN AND RELATED COMPOUNDS

The magnetic susceptibility from 2.2 to 200 °K was measured for hemin and the related α,β,γ, δ-tetraphenyl-porphiniron(III) chloride, thiocyanate, bromide, and iodide. All were found to be high-spin with the 6A1 ground state predominating over the temperature range studied. An analytical expression for the susceptibility as a function of temperature and zero-field splitting, D, could not describe the data with reasonable values of D in all cases. At 2.2 and 4.2°K, and varying values of the applied field, the compounds approached 90% of paramagnetic saturation. A compound which has been formulated to date as the hydroxide derivative of α,β,γ, δ-tetraphenylporphiniron(III) was found to be diamagnetic at low temperatures. © 1969, American Chemical Society. All rights reserved.