One-electron oxidation of the beta-diketiminate titanium(III) bis-neopentyl complex (Nacnac)Ti(CH2tBu)2 (Nacnac = [Ar]NC(Me)CHC(Me)N[Ar], Ar = 2,6-(CHMe2)2C6H3) promotes alpha-abstraction to afford the rare and terminal four-coordinate neopentylidene (Nacnac)Ti=CHtBu(OTf), which was structurally characterized. Alkylidene (Nacnac)Ti=CHtBu(OTf) reacts cleanly with benzophenone and the imine functionality of the Nacnac ligand to afford the corresponding Wittig-type products.
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http://dx.doi.org/10.1021/ja034786n | DOI Listing |
J Am Chem Soc
July 2024
Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States.
The iron-molybdenum cofactor of nitrogenase (FeMoco) catalyzes fixation of N via Fe hydride intermediates. Our understanding of these species has relied heavily on the characterization of well-defined 3d metal hydride complexes, which serve as putative spectroscopic models. Although the Fe ions in FeMoco, a weak-field cluster, are expected to adopt locally high-spin Fe configurations, synthetically accessible hydride complexes featuring d or d electron counts are almost exclusively low-spin.
View Article and Find Full Text PDFInorg Chem
April 2024
Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany.
In the pursuit of terminal tin chalcogenides, heteroleptic stannylenes bearing terphenyl- and hexamethyldisilazide ligands were reacted with carbodiimides to yield the respective guanidinato complexes. Further supported by quantum chemical calculations, this revealed that the -propyl-substituted derivative provides the maximum steric protection achievable. Oxidation with elemental selenium produced monomeric terminal tin selenides with four-coordinate tin centers.
View Article and Find Full Text PDFOrganometallics
February 2024
Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States.
We report herein the synthesis and characterization of a terminal Co(III) imido complex supported by an intermediate field N,N,C heteroscorpionate. This chemistry is enabled through the development of an additional member of this ligand type featuring Ph(CH)C- substituents, one of which weakly binds and stabilizes Co in the corresponding Co(I) precursor. The Co(III) imide is low-spin with no evidence for thermal population of open-shell excited states.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
March 2023
Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.
Diiron cofactors in enzymes perform diverse challenging transformations. The structures of high valent intermediates (Q in methane monooxygenase and X in ribonucleotide reductase) are debated since Fe-Fe distances of 2.5-3.
View Article and Find Full Text PDFChemistry
March 2023
Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, 07745, Jena, Germany.
Two four-coordinate organoboron N,C-chelate complexes with different functional terminals on the PEG chains are studied with respect to their photophysical properties within human MCF-7 cells. Their excited-state properties are characterized by time-resolved pump-probe spectroscopy and fluorescence lifetime microscopy. The excited-state relaxation dynamics of the two complexes are similar when studied in DMSO.
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