@article{HanftRottschaeferWieprechtetal.2021,
  author    = {Hanft, Anna and Rottsch{\"a}fer, Dennis and Wieprecht, Nele and Geist, Felix and Radacki, Krzysztof and Lichtenberg, Crispin},
  title     = {Aminotroponiminates: Impact of the NO\(_{2}\) Functional Group on Coordination, Isomerisation, and Backbone Substitution},
  series = {Chemistry—A European Journal},
  volume    = {27},
  journal   = {Chemistry—A European Journal},
  number    = {57},
  doi       = {10.1002/chem.202102324},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256988},
  pages     = {14250-14262},
  year      = {2021},
  abstract  = {Aminotroponiminate (ATI) ligands are a versatile class of redox-active and potentially cooperative ligands with a rich coordination chemistry that have consequently found a wide range of applications in synthesis and catalysis. While backbone substitution of these ligands has been investigated in some detail, the impact of electron-withdrawing groups on the coordination chemistry and reactivity of ATIs has been little investigated. We report here Li, Na, and K salts of an ATI ligand with a nitro-substituent in the backbone. It is demonstrated that the NO2 group actively contributes to the coordination chemistry of these complexes, effectively competing with the N,N-binding pocket as a coordination site. This results in an unprecedented E/Z isomerisation of an ATI imino group and culminates in the isolation of the first "naked" (i. e., without directional bonding to a metal atom) ATI anion. Reactions of sodium ATIs with silver(I) and tritylium salts gave the first N,N-coordinated silver ATI complexes and unprecedented backbone substitution reactions. Analytical techniques applied in this work include multinuclear (VT-)NMR spectroscopy, single-crystal X-ray diffraction analysis, and DFT calculations.},
  language  = {en}
}
@article{HanftRadackiLichtenberg2021,
  author    = {Hanft, Anna and Radacki, Krzysztof and Lichtenberg, Crispin},
  title     = {Cationic Bismuth Aminotroponiminates: Charge Controls Redox Properties},
  series = {Chemistry - A European Journal},
  volume    = {27},
  journal   = {Chemistry - A European Journal},
  number    = {20},
  doi       = {10.1002/chem.202005186},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225669},
  pages     = {6230 -- 6239},
  year      = {2021},
  abstract  = {The behavior of the redox-active aminotroponiminate (ATI) ligand in the coordination sphere of bismuth has been investigated in neutral and cationic compounds, [Bi(ATI)\(_{3}\)] and [Bi(ATI)\(_{2}\)L\(_{n}\)][A] (L=neutral ligand; n=0, 1; A=counteranion). Their coordination chemistry in solution and in the solid state has been analyzed through (variable-temperature) NMR spectroscopy, line-shape analysis, and single-crystal X-ray diffraction analyses, and their Lewis acidity has been evaluated by using the Gutmann-Beckett method (and modifications thereof). Cyclic voltammetry, in combination with DFT calculations, indicates that switching between ligand- and metal-centered redox events is possible by altering the charge of the compounds from 0 in neutral species to +1 in cationic compounds. This adds important facets to the rich redox chemistry of ATIs and to the redox chemistry of bismuth compounds, which is, so far, largely unexplored.},
  language  = {en}
}