TRANSITION-METAL COMPLEXES WITH THIOSEMICARBAZIDE-BASED LIGANDS .14. IRON(IV) COMPLEXES WITH 2,4-PENTANEDIONE BIS(S-ALKYLISOTHIOSEMICARBAZONE) - CRYSTAL AND MOLECULAR-STRUCTURE OF IODO(2,4-PENTANEDIONE BIS(S-ETHYLISOTHIOSEMICARBAZONATO)(3-))IRON(IV)

A method of template synthesis yielded the following complexes of iron(IV) and 2,4-pentanedione bis(S-alkylisothiosemicarbazone) (H3R2L): [Fe(R2L)I], R = CH3 (1), C2H5 (2), n-C3H7 (3), and n-C4H9 (4). The X-ray analysis of 2 showed the crystal belongs to the triclinic system, space group P1BAR, with a = 8.622 (1) angstrom, b = 8.764 (1) angstrom, c = 13.058 (1) angstrom, alpha = 73.38 (1)-degrees, beta = 85.87 (1)-degrees gamma = 68.96 (1)-degrees, d(calc) = 1.805 g cm-3, Z = 2, and molecular formula C11H19FeIN6S2. The structure was solved by direct method using SHELXS-86 and refined anisotropically by the least-squares method, employing 2137 unique reflections with I greater-than-or-equal-to 3 sigma(I). The hydrogen atoms were located and refined by isotropic approximation. The final R was 0.022. Compound 2 has a square-pyramidal structure with the quadridentate ligand (R2L)3- in the plane of thc central ion (deviation from the pyramid base plane 0.389 angstrom) and I- in the apical position. The results from magnetic measurements and Mossbauer spectra for 1-4 indicate the S = 1 state for the central ion. The complexes were also characterized by mass spectrometry.