EPR studies of reduced Zn-chlorins and their isotope substituted analogues

Radical anions of Zn-chlorin, Zn-octaethylchlorin complexes and their ¹⁵N and deuterium substituted analogues have been studied by EPR spectroscopy and the INDO molecular orbital method in the unrestricted Hartree-Fock procedure. Parameters of experimental spectra, determined by using the iterative least-squares fitting method, have been compared with those calculated on the basis of spin density distribution. A satisfactory agreement between the experimental hyperfine coupling constants and theoretical ones for the systems studied has been obtained.