Synthesis, spectral, structural and antimicrobial studies of fluorinated porphyrins

We have reported the synthesis, spectral and anti-microbial studies of 5,10,15,20-tetrakis(4′-trifluoromethylphenyl)porphyrin derivatives, MT(4′-CF3P)Ps where M = 2H, 1; Fe(II), 2; Ni(II), 3; Cu(II), 4; Zn(II), 5 and Pt(II), 6. The optical absorption and steady state fluorescence spectra of 1–6 show characteristic bands comparable with MTPPs. Compounds 1 and 3–5 were structurally characterized using single crystal X-ray diffraction analysis; 1 and 4 crystallized in the triclinic system, whereas 3 and 5 in the monoclinic system. The high spin nickel(II) ion in 3 is well placed at the center of the planar porphyrin core, which is influenced by the presence of trifluoromethylphenyl groups at the periphery and two THF molecules in apex positions. The porphyrins 1 and 3–5 are arranged in a slip-stacked fashion involving C–H⋯π and C–F⋯H(sol) intermolecular close contacts for 1, 4 and 3, 5, respectively. The role of non-covalent interactions involving the trifluoromethylphenyl groups in the crystal packing have been analyzed and quantified using Hirshfeld surface analysis. The antimicrobial activity of the free ligand is higher compared to its metal complexes.

Effect of trifluoromethylphenyl groups: The free ligand and the copper(II) complex of MT(4′-CF3P)Ps are non-isostructural, being influenced by intermolecular interactions involving trifluoromethylphenyl groups and solvent (THF) molecules. It is evident from Hirshfeld surface analysis that the arrangements of the supramolecular networks are dictated by the close contacts involving fluorine (F⋯H) and other C⋯H and H⋯H contacts.Figure optionsDownload as PowerPoint slideThe fluorescent quantum yield and the antimicrobial activity of the free ligand is higher compared to its metal complexes.