Synthesis, EPR and DFT calculations of rare Ag(II)porphyrins and the crystal structure of [Zn(II)tetrakis(4-bromo-2-thiophene)porphyrin]

Meso-tetrakis (4-bromo-2-thiophene) and (5-bromo-2-thiophene) porphyrins were synthesized in 18% yield from freshly distilled pyrrole and the corresponding aldehydes in refluxing propionic acid. Reaction of both porphyrins with either Zn(OAc) 2 \ub7 2H 2 O or Ag(OAc) afforded the corresponding metal complexes in 20% yield. The free bases and metal complexes were characterized by IR, NMR, EPR, MS and XPS. The crystal structure of 5,10,15,20(4-bromo-2-thiophene)porphyrinato Zn(II) was determined by X-ray diffraction and shows a \u27zigzag-like\u27 packing pattern due to S\ub7\ub7\ub7S intermolecular interaction. Structural features of these molecules are discussed by DFT quantum chemical calculations. \ua9 2008 Elsevier B.V. All rights reserved