FE-57,C-13 COUPLING-CONSTANTS FROM INVERSE DETECTION EXPERIMENTS AT NATURAL ISOTOPE ABUNDANCE

The possibility of measuring Fe-57,C-13 coupling constants and C-13/C- 12 isotope effects on Fe-57 nuclei by 'pseudotriple' and 'pseudo-quadr uple' resonance experiments using (H-1,Fe-57), (H-1,Fe-57)-((31)p) and ((31)p,C-13)-C-13,H-1) HMQC inverse correlations with Psi-BIRD or bi- selective pulses is demonstrated, Fe-57,H-1 coupling constants in the range of 1-2 Hz were used for the polarization transfer,(1)J and (2)J Fe-57,C-13 coupling constants, their relative signs, and isotopic shif ts (1) Delta(13/12)C(Fe-57) were determined for the first time in (cyc lopentadienyl)iron complexes with Fe-57 and C-13 in natural isotope ab undance.