Single or paired?

• Verfasst von: Ott, Jonas C. [VerfasserIn]
• Verfasst von: Isak, Daniel [VerfasserIn]
• Verfasst von: Melder, Julian J. [VerfasserIn]
• Verfasst von: Wadepohl, Hubert [VerfasserIn]
• Verfasst von: Gade, Lutz H. [VerfasserIn]
• Titel: Single or paired?
• Titelzusatz: Structure and reactivity of PNP-chromium(II) hydrides
• Verf.angabe: Jonas C. Ott, Daniel Isak, Julian J. Melder, Hubert Wadepohl, Lutz H. Gade
• E-Jahr: 2020
• Jahr: September 15, 2020
• Umfang: 10 S.
• Fussnoten: Gesehen am 21.12.2020
• Titel Quelle: Enthalten in: Inorganic chemistry
• Ort Quelle: Washington, DC : American Chemical Society, 1962
• Jahr Quelle: 2020
• Band/Heft Quelle: 59(2020), 19, Seite 14526-14535
• ISSN Quelle: 1520-510X
• DOI: doi:10.1021/acs.inorgchem.0c02315
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1743296185

Abstract

The preparation and reactivity of a range of novel paramagnetic chromium(II) complexes supported by a carbazole-based PNP pincer ligand is reported. Deprotonation of the ligand precursors R(PNP)H (1R) and subsequent reaction with chromium(II) chloride led to the formation of square-planar chlorido complexes R(PNP)CrCl (2R). Further reaction with various alkylating agents resulted in the isolation of chromium alkyl complexes R(PNP)CrR′ (3R-R′) which were then hydrogenated to yield two rare examples of paramagnetic chromium(II) hydrides 4iPr and 4tBu. Both compounds were characterized by X-ray diffraction and paramagnetic NMR spectroscopy supported by a comprehensive DFT-supported assignment of the resonances. While the di(tert-butyl)phosphino PNP substituted complex 4tBu was found to exhibit a monomeric square-planar molecular structure, its isopropyl-substituted analog 4iPr forms a dimer, also indicated by a strong antiferromagnetic coupling of the chromium centers. The pronounced reactivity of these compounds toward C═X double bonds was demonstrated by reaction with benzophenone, N,N′-dicyclohexylcarbodiimide, and carbon dioxide, which gave the corresponding insertion products. The alkoxido complex 5iPr, the amidinato complex 6iPr, and the formato compound 7tBu were also characterized by X-ray diffraction.