Structural and spectroscopy studies of the zinc complex of p-hydroxyphenylporphyrin

The tetrakis[(p-hydroxyphenyl)porphyrinato]zinc(II) compound [Zn(C44H28N4O4)]. DMF·H2O has been synthesized and its molecular structure precisely characterized by single-crystal analysis as well as other spectroscopic techniques. All the species in the structure are involved in hydrogen bonds, thus generating an extensive bidimensional supramolecular arrangement based on dimethylformamide and water molecules. The X-ray diffraction data show the existence of a centrosymmetric crystalline structure (P21/n); the presence of inversion symmetry element points to the inactivity of some vibrational bands in both infrared and Raman techniques. The most prominent band in the infrared spectrum, assigned to the asymmetric stretching of the CαCm groups at 1653 cm−1, is inactive in the Raman spectrum, whereas bands at 1544 and 1363 cm−1, related to the coupled v[(CβCβ) + (CαCm)] plus the symmetric stretching involving the pyrrolic ring and v(CC) of phenyl groups, respectively, are observed only in the Raman technique.