Synthesis, spectroscopic and structural characterization of the pentacoordinate high-spin Fe(III) isothiocyanate 'picket fence' porphyrin complex

摘要

The preparation and the characterization of the (isothiocyanato) (alpha,alpha,alpha,alpha-tetrakis(o-pivalamidophenyl)porphinato)iron(III) complex is described. The synthesis procedure utilizes the crown ether 18-C-6 to solubilize potassium thiocyanate. H-1 NMR and EPR data of the isolated product are in accordance with a high-spin (S = 5/2) ferric porphyrin species. The X-ray molecular structure confirms the above deductions. The iron atom is pentacoordinated by the four nitrogen atoms of the pyrrole rings of the porphyrin and the nitrogen atom of the NCS- group. It lies at 0.504 Angstrom out of the porphinato plane and 0.462 Angstrom out of the four nitrogen plane. The Fe-N(NCS) bond length is 1.956(5)Angstrom and the Fe-N-C(NCS) bond angle is 176.1(5)degrees. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 21]