FeIII, CuII and ZnII Complexes of the Rigid 9-Oxido-phenalenone Ligand—Spectroscopy, Electrochemistry, and Cytotoxic Properties
Autor: | Ingo Ott, Simon Schmitz, Katharina Butsch, Alexander Haseloer, Axel Klein, Julia Schur |
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Jazyk: | angličtina |
Rok vydání: | 2021 |
Předmět: |
Acetylacetone
Iron 010402 general chemistry Ligands 01 natural sciences Catalysis Article law.invention Inorganic Chemistry lcsh:Chemistry chemistry.chemical_compound Electron transfer Paramagnetism law Coordination Complexes antiproliferative Neoplasms Pentanones Electrochemistry Humans Physical and Theoretical Chemistry Electron paramagnetic resonance Spectroscopy Molecular Biology lcsh:QH301-705.5 Tetrahydrofuran Cell Proliferation 010405 organic chemistry Ligand 9-oxido-phenalenone Spectrum Analysis Organic Chemistry zinc General Medicine Phenalenes 0104 chemical sciences Computer Science Applications Crystallography Ferrocene chemistry lcsh:Biology (General) lcsh:QD1-999 copper redox MCF-7 Cells Cisplatin HT29 Cells |
Zdroj: | International Journal of Molecular Sciences, Vol 22, Iss 3976, p 3976 (2021) International Journal of Molecular Sciences Volume 22 Issue 8 |
ISSN: | 1661-6596 1422-0067 |
Popis: | The three complexes [Fe(opo)3], [Cu(opo)2], and [Zn(opo)2] containing the non-innocent anionic ligand opo− (opo− = 9-oxido-phenalenone, Hopo = 9-hydroxyphenalonone) were synthesised from the corresponding acetylacetonates. [Zn(opo)2] was characterised using 1H nuclear magnetic resonance (NMR) spectroscopy, the paramagnetic [Fe(opo)3] and [Cu(opo)2] by electron paramagnetic resonance (EPR) spectroscopy. While the EPR spectra of [Cu(opo)2] and [Cu(acac)2] in dimethylformamide (DMF) solution are very similar, a rather narrow spectrum was observed for [Fe(opo)3] in tetrahydrofuran (THF) solution in contrast to the very broad spectrum of [Fe(acac)3] in THF (Hacac = acetylacetone, 2,4-pentanedione acac− = acetylacetonate). The narrow, completely isotropic signal of [Fe(opo)3] disagrees with a metal-centred S = 5/2 spin system that is observed in the solid state. We assume spin-delocalisation to the opo ligand in the sense of an opo− to FeIII electron transfer. All compounds show several electrochemical opo-centred reduction waves in the range of −1 to −3 V vs. the ferrocene/ferrocenium couple. However, for CuII and FeIII the very first one-electron reductions are metal-centred. Electronic absorption in the UV to vis range are due to π–π* transitions in the opo core, giving Hopo and [Zn(opo)2] a yellow to orange colour. The structured bands ranging from 400 to 500 for all compounds are assigned to the lowest energy π−π* transitions. They show markedly higher intensities and slight shifts for the CuII (brown) and FeIII (red) complexes and we assume admixing metal contributions (MLCT for CuII, LMCT for FeIII). For both complexes long-wavelength absorptions assignable to d–d transitions were detected. Detailed spectroelectrochemical experiments confirm both the electrochemical and the optical assignments. Hopo and the complexes [Cu(opo)2], [Zn(opo)2], and [Fe(opo)3] show antiproliferative activities against HT-29 (colon cancer) and MCF-7 (breast cancer) cell lines in the range of a few µM, comparable to cisplatin under the same conditions. |
Databáze: | OpenAIRE |
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