A series of ruthenium(II) hydrido dinitrogen complexes supported by pincer ligands in different formal oxidation states have been prepared and characterized. Treating a ruthenium dichloride complex supported by the pincer ligand bis(di-tert-butylphosphinoethyl)amine (H-PNP) with reductant or base generates new five-coordinate cis-hydridodinitrogen ruthenium complexes each containing different forms of the pincer ligand. Further ligand transformations provide access to the first isostructural set of complexes featuring all six different forms of the pincer ligand. The conserved cis-hydridodinitrogen structure facilitates characterization of the π-donor, π-acceptor, and/or σ-donor properties of the ligands and assessment of the impact of ligand-centered multielectron/multiproton changes on N activation. Crystallographic studies, infrared spectroscopy, and N NMR spectroscopy indicate that N remains weakly activated in all cases, providing insight into the donor properties of the different pincer ligand states. Ramifications on applications of (pincer)Ru species in catalysis are considered.
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http://dx.doi.org/10.1021/acs.inorgchem.7b02889 | DOI Listing |
Dalton Trans
December 2024
Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
We report the proton-coupled electron transfer (PCET) reactivity of an octahedral Ta(V) aniline complex supported by an acridane-derived redox active NNN pincer ligand. The reversible binding of aniline to a Ta(V) dichloride induces significant coordination-induced bond weakening (CIBW) of the aniline N-H bonds. This enables a rare two-fold hydrogen atom abstraction, resulting in a terminal imido complex and a two-electron oxidation of the NNN pincer ligand, all while maintaining the metal's oxidation state.
View Article and Find Full Text PDFChem Asian J
December 2024
Ashoka University, Chemistry, Rajiv Gandhi Educational Hub, India, 131029, Sonipat, INDIA.
The catalytic efficiency of M-H2tpda pincer complexes (M = Mn(I), Fe(II), Co(III)) in CO2 hydrogenation, emphasizing the role of transition metal center variability have been discussed. The DFT analysis demonstrates that complexes with low αR values form weaker M-H bonds, enhancing catalyst reactivity with the elongation of M-H bond. The analysis further displays excellent catalytic performance for Mn-H2tpda (ΔE = 20.
View Article and Find Full Text PDFChemistry
December 2024
Universiteit Utrecht, Chemistry, Universiteitsweg 99, 3584CG, Utrecht, NETHERLANDS, KINGDOM OF THE.
Nickelacyclobutanes are reactive intermediates in catalytic cycles involving cyclopropanation and insertion reactions. The stoichiometric study of these intermediates has shown that their reactivity is highly influenced by the coordination environment of the nickel center. A pentacoordinated nickelacyclobutane embedded in a diphosphine pincer ligand has been shown to selectively undergo various reactions with exogenous ligands, including [2+2] cycloreversion and carbene transfer to an isocyanide.
View Article and Find Full Text PDFInorg Chem
December 2024
Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
Thioxanthone (TX) molecules and their derivatives are well-known photoactive compounds. Yet, there exist only a handful of luminescent systems combining TX with transition metals. Recently, we reported a TX-based PSP pincer ligand () that appears as a promising platform for filling this niche.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, Rajasthan 342037, India.
An Earth-abundant Mn-PNP pincer complex-catalyzed terpenylation of cyclic and acyclic ketones and secondary alcohol 1-phenylethanol using isoprenoid derivatives prenol, nerol, phytol, solanesol, and E-farnesol as allyl surrogates is reported. The C-C coupling reactions are green and atom-economic, proceeding via dehydrogenation of alcohols following a hydrogen autotransfer methodology aided by metal-ligand cooperation.
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