Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)]
The series of iridium(III) complexes, [Ir(ppy)<sub>2</sub>(RCOCHCOR′)], with R = CH<sub>3</sub> and R′ = CH<sub>3</sub> (<b>1</b>), Rc (<b>2</b>), and Fc (<b>3</b>), as well as R = Rc and R′ = Rc (<b>4</b>) or Fc (&l...
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2024-11-01
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| author | Blenerhassitt E. Buitendach Elizabeth Erasmus Eleanor Fourie Frederick P. Malan Jeanet Conradie J. W. (Hans) Niemantsverdriet Jannie C. Swarts |
| author_facet | Blenerhassitt E. Buitendach Elizabeth Erasmus Eleanor Fourie Frederick P. Malan Jeanet Conradie J. W. (Hans) Niemantsverdriet Jannie C. Swarts |
| author_sort | Blenerhassitt E. Buitendach |
| collection | DOAJ |
| description | The series of iridium(III) complexes, [Ir(ppy)<sub>2</sub>(RCOCHCOR′)], with R = CH<sub>3</sub> and R′ = CH<sub>3</sub> (<b>1</b>), Rc (<b>2</b>), and Fc (<b>3</b>), as well as R = Rc and R′ = Rc (<b>4</b>) or Fc (<b>5</b>), and R = R′ = Fc (<b>6</b>), ppy = 2-phenylpyridinyl, Fc = Fe<sup>II</sup>(η<sup>5</sup>–C<sub>5</sub>H<sub>4</sub>)(η<sup>5</sup>–C<sub>5</sub>H<sub>5</sub>), and Rc = Ru<sup>II</sup>(η<sup>5</sup>–C<sub>5</sub>H<sub>4</sub>)(η<sup>5</sup>–C<sub>5</sub>H<sub>5</sub>), has been investigated by single-crystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS) supplemented by DFT calculations. Here, in the range of 3.74 ≤ Σχ<sub>R</sub> ≤ 4.68, for Ir 4f, Ru 3d and 3p and N 1s orbitals, binding energies unexpectedly decreased with increasing Σχ<sub>R</sub> (Σχ<sub>R</sub> = 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 Σχ<sub>R</sub>. 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 Σχ<sub>R</sub> followed opposite trend directions than binding energy/Σχ<sub>R</sub> trends. X-ray-induced decomposition of compounds was observed. The results confirmed good communication between molecular fragments. Lower binding energies of both the Ir 4f<sub>7/2</sub> and N 1s photoelectron lines are associated with shorter Ir-N bond lengths. Cytotoxic tests showed that <b>1</b> (IC<sub>50</sub> = 25.1 μM) and <b>3</b> (IC<sub>50</sub> = 37.8 μM) are less cytotoxic against HeLa cells than cisplatin (IC<sub>50</sub> = 1.1 μM), but more cytotoxic than the free β-diketone FcCOCH<sub>2</sub>COCH<sub>3</sub> (IC<sub>50</sub> = 66.6 μM). |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2024-11-01 |
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| series | Molecules |
| spelling | doaj-art-a366b249018f42c9aa19d5b5162a9af72024-11-26T18:15:47ZengMDPI AGMolecules1420-30492024-11-012922538310.3390/molecules29225383Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)]Blenerhassitt E. Buitendach0Elizabeth Erasmus1Eleanor Fourie2Frederick P. Malan3Jeanet Conradie4J. W. (Hans) Niemantsverdriet5Jannie C. Swarts6Department of Chemistry, University of the Free State, Bloemfontein 9300, South AfricaDepartment of Chemistry, University of the Free State, Bloemfontein 9300, South AfricaDepartment of Chemistry, University of the Free State, Bloemfontein 9300, South AfricaDepartment of Chemistry, University of Pretoria, Pretoria 0002, South AfricaDepartment of Chemistry, University of the Free State, Bloemfontein 9300, South AfricaSyngaschem, Valeriaanlaan 16, 5672 XD Nuenen, The NetherlandsDepartment of Chemistry, University of the Free State, Bloemfontein 9300, South AfricaThe series of iridium(III) complexes, [Ir(ppy)<sub>2</sub>(RCOCHCOR′)], with R = CH<sub>3</sub> and R′ = CH<sub>3</sub> (<b>1</b>), Rc (<b>2</b>), and Fc (<b>3</b>), as well as R = Rc and R′ = Rc (<b>4</b>) or Fc (<b>5</b>), and R = R′ = Fc (<b>6</b>), ppy = 2-phenylpyridinyl, Fc = Fe<sup>II</sup>(η<sup>5</sup>–C<sub>5</sub>H<sub>4</sub>)(η<sup>5</sup>–C<sub>5</sub>H<sub>5</sub>), and Rc = Ru<sup>II</sup>(η<sup>5</sup>–C<sub>5</sub>H<sub>4</sub>)(η<sup>5</sup>–C<sub>5</sub>H<sub>5</sub>), has been investigated by single-crystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS) supplemented by DFT calculations. Here, in the range of 3.74 ≤ Σχ<sub>R</sub> ≤ 4.68, for Ir 4f, Ru 3d and 3p and N 1s orbitals, binding energies unexpectedly decreased with increasing Σχ<sub>R</sub> (Σχ<sub>R</sub> = 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 Σχ<sub>R</sub>. 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 Σχ<sub>R</sub> followed opposite trend directions than binding energy/Σχ<sub>R</sub> trends. X-ray-induced decomposition of compounds was observed. The results confirmed good communication between molecular fragments. Lower binding energies of both the Ir 4f<sub>7/2</sub> and N 1s photoelectron lines are associated with shorter Ir-N bond lengths. Cytotoxic tests showed that <b>1</b> (IC<sub>50</sub> = 25.1 μM) and <b>3</b> (IC<sub>50</sub> = 37.8 μM) are less cytotoxic against HeLa cells than cisplatin (IC<sub>50</sub> = 1.1 μM), but more cytotoxic than the free β-diketone FcCOCH<sub>2</sub>COCH<sub>3</sub> (IC<sub>50</sub> = 66.6 μM).https://www.mdpi.com/1420-3049/29/22/5383iridiumferroceneruthenoceneβ-diketonato complexesX-ray photoelectron spectroscopyDFT calculations |
| spellingShingle | Blenerhassitt E. Buitendach Elizabeth Erasmus Eleanor Fourie Frederick P. Malan Jeanet Conradie J. W. (Hans) Niemantsverdriet Jannie C. Swarts Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)] Molecules iridium ferrocene ruthenocene β-diketonato complexes X-ray photoelectron spectroscopy DFT calculations |
| title | Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)] |
| title_full | Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)] |
| title_fullStr | Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)] |
| title_full_unstemmed | Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)] |
| title_short | Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir<sup>III</sup>(ppy)<sub>2</sub>(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)<sub>2</sub>(FcCOCHCORc)] |
| title_sort | unexpected xps binding energy observations further highlighted by dft calculations of ruthenocene containing ir sup iii sup ppy sub 2 sub rcochcorc complexes cytotoxicity and crystal structure of ir ppy sub 2 sub fccochcorc |
| topic | iridium ferrocene ruthenocene β-diketonato complexes X-ray photoelectron spectroscopy DFT calculations |
| url | https://www.mdpi.com/1420-3049/29/22/5383 |
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