The spin transition of high-spin (/sup 5/T/sub 2/).harlor.low-spin (/sup 1/A/sub 1/) of (dithiocyanato) (N-phenyl-2-pyridinaldimine) iron (II) complexes can be altered by substituents on the phenyl ring. Mossbauer spectra at 78 K for the 4-substituted derivatives (with the exception of the 4-OH-substituted derivative) indicate that the fraction of low-spin states increases with decreasing substituent electron-withdrawing ability, as measured by the Hammet .sigma. constant (4-OCH/sub 3/<4-CH/sub 3/CONH 4-C/sub 6/H/sub 5/<4-CH/sub 3/<4-H<4-Cl<4-NO/sub 2/). In addition, the effect of methyl-substitution at the ortho-, meta- or paraposition of the phenyl ring on the apin transition was examined. Mossbauer spectra of these methyl-substituted complexes reveal quite different spin equilibria.
The spin transition of high-spin (/sup 5/T/sub 2/).harlor.low-spin (/sup 1/A/sub 1/) of (dithiocyanato) (N-phenyl-2-pyridinaldimine) iron (II) complexes can be altered by substituents on the phenyl ring. Mossbauer spectra at 78 K for the 4-substituted derivatives (with the exception of the 4-OH-substituted derivative) indicate that the fraction of low-spin states increases with decreasing substituent electron-withdrawing ability, as measured by the Hammet .sigma. constant (4-OCH/sub 3/<4-CH/sub 3/CONH 4-C/sub 6/H/sub 5/<4-CH/sub 3/<4-H<4-Cl<4-NO/sub 2/). In addition, the effect of methyl-substitution at the ortho-, meta- or paraposition of the phenyl ring on the apin transition was examined. Mossbauer spectra of these methyl-substituted complexes reveal quite different spin equilibria.
Relation:
中國化學會會誌=Journal of the Chinese Chemical Society 32(4)，頁399-403
