The bulky monodentate carbazolyl ligand 1,8-bis(3,5-dibutylphenyl)-3,6-dibutylcarbazole (Cbz) was employed in the synthesis of monomeric heteroleptic amido carbazolyl complexes of Ca and Yb. For both central metal atoms, dimeric hydride complexes [(Cbz)Ca(benzene)H], [(Cbz)Ca(THF)H], [(Cbz)Yb(benzene)H] and [(Cbz)Yb(THF)H] were obtained, which show remarkably poor solubility in organic solvents. The characteristic hydride H NMR resonance of [(Cbz)Ca(benzene)H] was observed at 2.07 ppm, and for the first time, characteristic vibrational modes of the CaH and YbH moiety are discussed. Despite their poor solubility, the hydride complexes could be reacted with CO to yield the corresponding ethenediolate complexes.
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http://dx.doi.org/10.1039/d4cc03714f | DOI Listing |
Chem Sci
December 2024
Department of Chemistry, University of York Heslington YO10 5DD UK
This work details how the unusual iridium tetrahydride [Ir(H)(IMes)(sulfoxide)]Na and trihydride [Ir(H)(IMes)(sulfoxide)] can be formed in a solvent dependent reaction of [IrCl(COD)(IMes)] with sulfoxide (dimethyl or methylphenyl), base, and H. In the case of dimethyl sulfoxide, the four hydride ligands of the tetrahydride are equivalent, and the IMes and sulfoxide ligands mutually . However, for phenyl methyl sulfoxide, this isomer of the tetrahydride forms alongside its counterpart where the remarkable symmetry breaking effect of the sulfoxide leads to it presenting four chemically distinct hydride ligands.
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December 2024
Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059 Rostock, Germany.
Starting from the alkyne complex CpZr(py)(η-MeSiCSiMe) (Cp = η-cyclopentadienyl, py = pyridine), the synthesis and complete characterisation of a zirconocene(IV) triazenido hydride complex and its use in the activation of small molecules is reported. The reaction with CO led to the formation of a zirconocene(IV) triazenido-formate complex, which was further investigated for its stability towards different bases with respect to the formation of formic acid. The experimentally observed reaction pathway was investigated computationally using DFT methods, revealing the favourable role of pyridine coordination in the hydrogen transfer from the triazene to the alkyne unit of the zirconocene reagent.
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December 2024
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
Effective activation of small molecules (alcohol, phenol, ketones, amine, .) by a hydrogen-bridged bis(silylene) complex, which has two adjacent Lewis acidic centers and a hydridic bridging hydrogen with weak Si⋯H bonds, is described, along with product characterization by NMR and X-ray diffraction studies.
View Article and Find Full Text PDFInorg Chem
December 2024
Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S-3H6, Canada.
Here it is demonstrated that there is a linear relationship between the terminal 3d metal hydride stretching wavenumber ν and the metal hydride distance reported to date: ν ∼ (-1.05 + 3.35) × 10 cm.
View Article and Find Full Text PDFBiochemistry
December 2024
Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019-0065, United States.
F-dependent glucose-6-phosphate dehydrogenase (FGD) catalyzes the conversion of glucose-6-phosphate (G6P) to 6-phosphogluconolactone, using cofactor F as the hydride transfer acceptor. Our previous pH dependence studies suggested that E109 serves as an active site acid, donating a proton to the N-1 position of F, while leaving the role of H40 unanswered, which was previously suggested to serve as the active site base. This work utilizes thermodynamic and kinetic studies to elucidate additional mechanistic details concerning the roles of H40 and E13.
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