Iron complexes of N-substituted thiosalicylideneimines. Part 4. Preparation, structure, and reactivity of pentadentate [N,N′-4-azaheptane-1,7-diylbis(thiosalicylideneiminato)]iron(II) derivatives

Abstract

The complex [N,N′-4-azaheptane-1,7-diylbis(thiosalicylideneiminato)]iron(II), [Fe(tsalah)], and the 4-methyl-4-azaheptane derivative, [Fe(tsalmah)], have been prepared by reaction of the parent thiosalicylaldehyde (Htsal) complex, [Fe(tsal)₂], with the appropriate amine. The molecular structure of [Fe(tsalmah)] has been determined. The compound crystallizes from dimethylformamide–ethanol in space group P2₁/n with unit-cell dimensions a= 21.018(9), b= 13.015(7), c= 15.476(8)Å, β= 91.98(9)°, and Z= 8. The structure has been refined to R= 0.071 and R′= 0.061 on the basis of 1 576 independent reflections. The molecule has a distorted trigonal-bipyramidal structure with the two S atoms and the aza N atom in the trigonal plane. The complexes are high spin and react with CO. Molecular oxygen causes rapid decomposition with the formation of the disulphides of the ligands.