Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization |
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| Authors: | Dr Bjorn Askevold Dr Marat M Khusniyarov Dr Wolfgang Kroener Dr Klaus Gieb Prof Paul Müller Dr Eberhardt Herdtweck Dr Frank W Heinemann Dr Martin Diefenbach Prof Max C Holthausen Veacheslav Vieru Prof Liviu F Chibotaru Prof Sven Schneider |
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| Affiliation: | 1. Department Chemie und Pharmazie, Universit?t Erlangen‐Nürnberg, Egerlandstr. 1, 91058 Erlangen (Germany);2. Department of Physics and Interdisciplinary Center for Molecular Materials, Universit?t Erlangen‐Nürnberg, Erwin‐Rommel‐Str. 1, 91058 Erlangen (Germany);3. Department Chemie, Technische Universit?t München, Lichtenbergstr. 4, 85748 Garching b. München (Germany);4. Institut für Anorganische und Analytische Chemie, Goethe‐Universit?t, Max‐von‐Laue‐Str. 7, 60438 Frankfurt am Main (Germany);5. Theory of Nanomaterials Group and INPAC, Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee (Belgium);6. Institut für Anorganische Chemie, Georg‐August‐Universit?t, Tammannstr. 4, 37077 G?ttingen (Germany) |
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| Abstract: | Functionalization of the PNP pincer ligand backbone allows for a comparison of the dialkyl amido, vinyl alkyl amido, and divinyl amido ruthenium(II) pincer complex series RuCl{N(CH2CH2PtBu2)2}], RuCl{N(CHCHPtBu2)(CH2CH2PtBu2)}], and RuCl{N(CHCHPtBu2)2}], in which the ruthenium(II) ions are in the extremely rare square‐planar coordination geometry. Whereas the dialkylamido complex adopts an electronic singlet (S=0) ground state and energetically low‐lying triplet (S=1) state, the vinyl alkyl amido and the divinyl amido complexes exhibit unusual triplet (S=1) ground states as confirmed by experimental and computational examination. However, essentially non‐magnetic ground states arise for the two intermediate‐spin complexes owing to unusually large zero‐field splitting (D>+200 cm?1). The change in ground state electronic configuration is attributed to tailored pincer ligand‐to‐metal π‐donation within the PNP ligand series. |
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| Keywords: | computer chemistry ligands magnetic properties NMR spectroscopy ruthenium |
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