Buitendach, Blenerhassitt E.Erasmus, ElizabethFourie, EleanorMalan, Frederick P.Conradie, JeanetNiemantsverdriet, J. W. (Hans)Swarts, Jannie C.2024-12-062024-12-062024Buitendach, B. E., Erasmus, E., Fourie, E., Malan, F. P., Conradie, J., Niemantsverdriet, J. W., & Swarts, J. C. (2024). Unexpected XPS binding energy observations further highlighted by DFT calculations of ruthenocene-containing [Irᴵᴵᴵ(ppy)₂(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)₂(FcCOCHCORc)]. Molecules, 29(22), 5383. https://doi.org/10.3390/molecules292253831420-3049 (online)https://doi.org/10.3390/molecules29225383http://hdl.handle.net/11660/12821The series of iridium(III) complexes, [Ir(ppy)₂(RCOCHCOR′)], with R = CH₃ and R′ = CH₃ (1), Rc (2), and Fc (3), as well as R = Rc and R′ = Rc (4) or Fc (5), and R = R′ = Fc (6), ppy = 2-phenylpyridinyl, Fc = Feᴵᴵ(η⁵–C₅H₄)(η⁵–C₅H₅), and Rc = Ruᴵᴵ(η⁵–C₅H₄)(η⁵–C₅H₅), has been investigated by singlecrystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS) supplemented by DFT calculations. Here, in the range of 3.74 ≤ ΣχR ≤ 4.68, for Ir 4f, Ru 3d and 3p and N 1s orbitals, binding energies unexpectedly decreased with increasing ΣχR (ΣχR = the sum of Gordy group electronegativities of the R groups on β-diketonato ligands = a measure of electron density on atoms), while in Fe 2p orbitals, XPS binding energy, as expected, increased with increasing ΣχR. Which trend direction prevails is a function of main quantum level, n = 1, 2, 3. . ., sub-quantum level (s, p, d, and f), initial state energies, and final state relaxation energies, and it may differ from compound series to compound series. Relations between DFT-calculated orbital energies and ΣχR followed opposite trend directions than binding energy/ΣχR trends. X-ray-induced decomposition of compounds was observed. The results confirmed good communication between molecular fragments. Lower binding energies of both the Ir 4f₇/₂ and N 1s photoelectron lines are associated with shorter Ir-N bond lengths. Cytotoxic tests showed that 1 (IC₅₀ = 25.1 μM) and 3 (IC₅₀ = 37.8 μM) are less cytotoxic against HeLa cells than cisplatin (IC₅₀ = 1.1 μM), but more cytotoxic than the free β-diketone FcCOCH₂COCH₃(IC₅₀ = 66.6 μM).enIdiumFerroceneRuthenoceneβ-diketonato complexesX-ray photoelectron spectroscopyDFT calculationsX-ray-induced decompositionCytotoxic propertiesAntibacterial activityArticleAuthor(s)https://creativecommons.org/licenses/by/4.0/