A series of (NHC)(cod)Ir(I) complexes bearing NHC-carboxylate ligands were efficiently synthesized and fully characterized. Their solid-state structures confirmed the bidentate coordination mode of these LX-type NHC ligands. These unprecedented iridium(I) complexes demonstrated efficient catalytic activities in dehydrogenative directed C-H silylation of arenes, and allowed for excellent -selectivity control with aromatic silylating agents.
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http://dx.doi.org/10.1039/d2cc06865f | DOI Listing |
Organometallics
December 2024
Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K.
stabilization of known, but solution unstable, methylidene complex [Ir(Bu-PONOP)(=CH)][BAr ] allows single-crystal to single-crystal solid/gas reactivity associated with the {Ir=CH} group to be studied. Addition of H results in [Ir(Bu-PONOP)(H)][BAr ]; exposure to CO forms iridium(I) carbonyl [Ir(Bu-PONOP)(CO)][BAr ], and reaction with NH gas results in the formation of methylamine complex [(Bu-PONOP)Ir(NHMe)][BAr ] via an aminocarbene intermediate. Periodic density functional theory and electronic structure analyses confirm the Ir=CH bond character but with a very low barrier to rotation around the Ir=CH bond.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemistry, Graduate School of Sciences, Tokyo Metropolitan University, Hachioji, 192-0397, Japan.
Stable neutral metal radicaloid complexes have been synthesized from a modified tetrapyrrolic pigment, bilatriene, with iridium(I) and rhodium(I) cyclooctadiene (COD) synthons. The bilatriene skeleton contains α-linked conjugated pyrrole units, whereas an N-confused analogue used in this work possesses β-linked pyrrole moieties at the terminal, demonstrating a unique metal binding capability. Unprecedentedly, the metal-COD cations are accommodated at the outer nitrogen sites, which induced the formation of open-shell metal-radicaloid species.
View Article and Find Full Text PDFDalton Trans
January 2025
Ruđer Bošković Institute, Bijenička c. 54, HR-10000 Zagreb, Croatia.
This publication describes monodentate phosphine and oxazoline ligands attached to an amino acid ester and the application of their supramolecularly assembled rhodium(I) or iridium(I) complexes in asymmetric catalysis. The major feature of these complexes is the transmission of chirality from distant hydrogen bonded amino acids to the prochiral catalytic metal center ("backdoor induction"). The generated homoleptic and heteroleptic rhodium(I) or iridium(I) precatalysts were studied by NMR, UV-VIS and CD spectroscopy as well as X-ray single crystal diffraction.
View Article and Find Full Text PDFChemistry
December 2024
Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1, Scotland, 1XL, U.K.
Hydrogen isotope exchange (HIE) via C-H activation constitutes an efficient method for the synthesis of isotopically-enriched compounds, which are crucial components of the drug discovery process and are extensively employed in mechanistic studies. A series of iridium(I) complexes, bearing a chelating phosphine-N-heterocyclic carbene ligand, was designed and synthesized for application in the catalytic HIE of challenging N- and O-aryl carbamates. A broad range of substrates were labeled efficiently, and applicability to biologically-relevant systems was demonstrated by labeling an ʟ-tyrosine-derived carbamate with excellent levels of deuterium incorporation.
View Article and Find Full Text PDFThe title compound, [Ir(CH)(CHN)(CHP)]BF, a new triazole-based N-heterocyclic carbene iridium(I) cationic complex with a tetra-fluorido-borate counter-anion, crystallizes with two cations and two anions in the asymmetric unit of space group . The Ir centers of the cations have distorted square-planar conformations, formed by a bidentate (η + η) cyclo-octa-1,5-diene (COD) ligand, an N-heterocyclic carbene and a tri-phenyl-phosphane ligand with the NHC carbon atom and P atom being . In the extended structure, non-classical C-H⋯F hydrogen bonds, one of which is notably short (H⋯F = 2.
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