0000000001300690
AUTHOR
Andreas Neidlinger
Anticancer Effect of an Electronically Coupled Oligoferrocene
The mode of anticancer activity of simple ferrocenes often relies on their intracellular oxidation with the formation of cytotoxic ferrocenium species. The former compounds should be considered as ...
Radical cation and dication of a 4H-dithieno[2,3-b:3′,2′-e][1,4]-thiazine
A p-tert-butylphenyl substituted 4H-dithieno[2,3-b:3′,2′-e][1,4]thiazine was synthesized by twofold Buchwald–Hartwig coupling. The electronic properties (UV/Vis, cyclic voltammetry and spectroelectrochemistry) and the DFT- and TD DFT-calculated electronic structure reveal that the parent system and the radical cation and dication oxidation products are highly polarizable π-systems with strong charge transfer contributions. The radical cation and the dication were prepared by oxidation with antimony(V) pentachloride, giving stable deeply colored salts. EPR spectroscopy of the radical cation furnishes hyperfine coupling constants with the nitrogen nucleus and the α-thienyl protons. The dicati…
Conformational Switching of Multi-Responsive Ferrocenyl-Phenol Conjugates
Multifunctional conformational switches based on the ferrocenyl-salicylic acid amide motif with increasing additional complexity at the Fc moiety (R = COOMe, CONHEt, CONHFc; H-2–H-4; Fc = ferrocenyl) have been prepared and their preferred secondary structures in solution have been elucidated by NMR and IR spectroscopy in combination with conformational searches based on DFT calculations. Their distinct conformational responses to deprotonation ([2]––[4]–) and oxidation ([H-2]+·–[H-4]+·) have been revealed by IR, EPR, and UV/Vis spectroscopy as well as by DFT calculations. Deprotonation inverts all amide units (double amide twist) whereas oxidation selectively flips the terminal amide unit (…
Spin Trapping of Carbon-Centered Ferrocenyl Radicals with Nitrosobenzene
In contrast to metal centered 17 valence electron radicals, such as [Mn(CO)5]•, ferrocenium ions [Fe(C5H5)2]+ (1+), [Fe(C5Me5)2]+ (2+), [Fe(C5H5)(C5H4Et)]+ (3+), [Fe(C5H5)(C5H4NHC(O)Me)]+ (4+), and [Fe(C5H5)(C5H4NHC(S)Me)]+ (5+) do not add to nitrosobenzene PhNO to give metal-coordinated stable nitroxyl radicals. In the presence of the strong and oxidatively stable phosphazene base tert-butylimino-tris(dimethylamino)phosphorane, the quite acidic ferrocenium ions 1+–5+ are deprotonated to give a pool of transient and persistent radicals with different deprotonation sites [1–Hx]•–[5–Hx]•. One rather persistent iron-centered radical [4–HN]•, deprotonated at the nitrogen atom, has been detected…
Proton-Coupled Electron Transfer in Ferrocenium–Phenolate Radicals
Electron and proton transfer (ET, PT) can be intimately coupled, provided suitable redox and acid/base sites are available. The amide-linked ferrocene–phenol H-1 is deprotonated to the phenolate [1]– by phosphazene bases and oxidized to the ferrocenium ion [H-1]+ by silver hexafluoroantimonate. Concomitant oxidation and deprotonation yields the radical [1]•, featuring a characteristic near-IR absorption band. The ground state of [1]• is best described as the ferrocenium–phenolate zwitterion [1b]• with a dynamic dissymmetric N···H···O hydrogen bond (PT). The ferrocenium–iminolate N···H–O tautomer [1b]•-NHO′ can undergo a thermal structural rearrangement to the high-energy OH···O tautomer [1b…
How Hydrogen Bonds Affect Reactivity and Intervalence Charge Transfer in Ferrocenium‐Phenolate Radicals
The ferrocenyl-phenol 2,4-di-tert-butyl-6-(ferrocenylcarbamoyl)phenol (H-1) forms intramolecular hydrogen bonds which are absent in its constitutional isomer 2,6-di-tert-butyl-4-(ferrocenylcarbamoyl)phenol (H-2). Their corresponding bases 1– and 2– show intra- and intermolecular NH···O hydrogen bonds, respectively. The phenolate 1– is reversibly oxidized to 1·, whereas 2– only undergoes a quasi-reversible oxidation to 2·, which suggests a higher reactivity. The radical pools of 1· and 2· formed by the oxidation/deprotonation of H-1 and H-2 have been probed by (rapid-freeze) electron paramagnetic resonance (EPR) spectroscopy and by spin-trapping techniques to elucidate the types of radicals …
CCDC 1993737: Experimental Crystal Structure Determination
Related Article: Gina Zeh, Philipp Haines, Matthias E. Miehlich, Torben Kienz, Andreas Neidlinger, Ralf P. Friedrich, Hülya G. Özkan, Christoph Alexiou, Frank Hampel, Dirk M. Guldi, Karsten Meyer, Jürgen Schatz, Katja Heinze, Andriy Mokhir|2020|Organometallics|39|3112|doi:10.1021/acs.organomet.0c00306
CCDC 1534633: Experimental Crystal Structure Determination
Related Article: Arno Schneeweis, Andreas Neidlinger, Guido J. Reiss, Walter Frank, Katja Heinze, Thomas J. J. Müller|2017|Org.Chem.Front.|4|839|doi:10.1039/C7QO00188F
CCDC 1441949: Experimental Crystal Structure Determination
Related Article: Andreas Neidlinger, Christoph Förster, Katja Heinze|2016|Eur.J.Org.Chem.|2016|4852|doi:10.1002/ejoc.201600774
CCDC 1426154: Experimental Crystal Structure Determination
Related Article: Andreas Neidlinger, Christoph Förster and Katja Heinze|2016|Eur.J.Inorg.Chem.||1274|doi:10.1002/ejic.201501471
CCDC 1993738: Experimental Crystal Structure Determination
Related Article: Gina Zeh, Philipp Haines, Matthias E. Miehlich, Torben Kienz, Andreas Neidlinger, Ralf P. Friedrich, Hülya G. Özkan, Christoph Alexiou, Frank Hampel, Dirk M. Guldi, Karsten Meyer, Jürgen Schatz, Katja Heinze, Andriy Mokhir|2020|Organometallics|39|3112|doi:10.1021/acs.organomet.0c00306