Varying the reaction ratio of cyclic (alkyl)(amino) carbene (cAACEt) with AlH3·NEtMe2 leads to the isolation of (cAACEtH)AlH2·NEtMe21 and (cAACEtH)2Al(μ-H)2AlH2·NEtMe22 and the first example of a monomeric dialkyl-aluminum hydride (cAACEtH)2AlH 3. VT and 1H-1H EXSY NMR experiments of 3 demonstrated the isomerization of the diastereomers of 3via the first instance of reversible hydride migration between the Al and the C center. In addition, heating solutions of 3 at 100 °C affords (cAACEtH)Al(CHC(Et)2CH2C(Me)2NC6H3(iPr)C(Me)CH2) 4 with loss of H2.
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http://dx.doi.org/10.1039/c8cc05013a | DOI Listing |
Chemistry
January 2025
Indian Institute of Technology Madras, Department of Chemistry, Chennai, Chennai, INDIA.
A series of significantly bulky mono- and di-substituted cyclic alkyl-amino carbene (cAAC)- functionalized cyclopentadiene ring (Cp) compounds were synthesized. The functionalization of the Cp ring with cAAC ligands makes them significantly bulkier, while retaining their ligation properties. These compounds display interesting fluorescence properties.
View Article and Find Full Text PDFThe synthesis of a transient cationic phosphaborene [(Mes*)P=B(CAAC)]+ (Mes* = 2,4,6,-trit-tert-butylphenyl, CAAC = cyclic alkylamino carbene) by halide abstraction from the B-brominated analogue is reported. This species was found to undergo rapid and selective intramolecular aliphatic C-H bond activation to yield a phosphinoborenium cation, which undergoes facile deprotonation to give a cyclic base-stabilized phosphaborene. Computational investigation of the mechanism of C-H activation indicates a boron-centred activation route with an exceptionally low barrier of 8 kJ mol-1, followed by a nearly barrierless hydride migration from boron to phosphorus.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517619, India.
Cyclic alkyl(amino) carbene (cAAC)-supported phosphaalkenides (cAACP) have been employed as ligands for the isolation of two atomically precise mixed valence paramagnetic AgI/012Cl, and AgI/010, nano-clusters [(Me-cAACP)AgCl] (2), and [(Me-cAACP)Ag](NTf) (4). 2 and 4 have been structurally characterized by single-crystal X-ray diffraction revealing the presence of three Ag atoms, nine Ag ions (2); and two Ag atoms, eight Ag ions (4), respectively. The clustering inorganic unit AgCl in 2 has been found to be surrounded by six mono-anionic μ-cAACP moieties having 3-bar symmetry.
View Article and Find Full Text PDFACS Catal
August 2024
Center for Catalysis Research & Innovation, and Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
Stability problems have limited the uptake of cationic olefin metathesis catalysts in chemical biology. Described herein are anionic catalysts that improve water-solubility, robustness, and compatibility with biomolecules such as DNA. A sulfonate tag is installed on the cyclic (alkyl)(amino) carbene (CAAC) ligand platform, chosen for resistance to degradation by nucleophiles, base, water, and β-elimination.
View Article and Find Full Text PDFInorg Chem
May 2024
School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637371 Singapore.
A digermanium(III) 1,2-dication comprises two cationic centers located at two interconnected Ge atoms. The strong Coulombic repulsion between two positively charged germanium cations hinders their bond formation. Balancing these two oppositions was achieved by using amidinate and cyclic (alkyl)amino carbene (cAAC)-phosphinidenide ligands, where an amidinato cAAC-phosphinidenidogermylene complex, [LGeP(cAAC)] (, where L = PhC(NBu), cAAC = :C{C(Me)CHC(Me)NAr}, and Ar = 2,6-PrCH), underwent one-electron oxidation with a bis(phosphinidene) radical cation, [(cAAC)P], to form a digermanium(III) 1,2-dication, [LGeP(cAAC)], in compound .
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