The use of the commercially available, bifunctional phosphine 1,3,5-triaza-7-phosphaadamantane (abbreviated as PN3) in conjunction with a series of Zn(salphen) complexes leads to sterically encumbered phosphine ligands as a result of (reversible) coordinative Zn-N interactions. The solid state and solution phase behaviour of these supramolecular ligand systems have been investigated in detail and revealed their stoichiometries in the solid state observed by X-ray crystallography, and those determined in solution by NMR and UV-Vis spectroscopy. Also, upon application of these supramolecular bulky phosphines in hydrosilylation catalysis employing 1-hexene as a substrate, the catalysis data infer the presence of an active Rh species with two coordinated, bulky PN3/Zn(salphen) assembly units having a maximum of three Zn(salphen)s associated per PN3 scaffold, with an excess of bulky phosphines hardly affecting the overall activity.
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http://dx.doi.org/10.1039/c3dt00078h | DOI Listing |
Angew Chem Int Ed Engl
January 2025
University of Basel, Department of Chemistry, St. Johanns-Ring 19, 4056, Basel, SWITZERLAND.
Despite the growing importance of planar chiral macrocyclophanes owing to their unique properties in different areas of chemistry, methods that are effective in controlling their planar chirality are restricted to certain molecular scaffolds. Herein, we report the first Pd(0)-catalyzed enantioselective intermolecular C-H arylation that induces planar chirality by installing bulky aryl groups through dynamic kinetic resolution (DKR). A computer-assisted approach allowed a fine-tuning of the structure of the employed chiral bifunctional phosphine-carboxylate ligands to achieve high enantioselectivities.
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January 2025
Departamento de Química Inorgánica, Universidad de Sevilla, 41012 Sevilla, Spain.
Preformed Ni(0) complexes are rarely used as precatalysts in cross-coupling reactions, although they can incorporate catalytically active nickel directly into the reaction. In this work, we focus on the preparation and the catalytic application of low-coordinate Ni(0) complexes supported by bulky monophosphine ligands in C-S cross-coupling reactions. We have prepared two families of Ni(0) complexes, bis-phosphine aducts of the type [Ni(PRAr')] (Ar' = -terphenyl group) and monophosphine derivatives of the type [Ni(PRAr')(DVDS)] (DVDS = divinyltetramethyldisiloxane).
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January 2025
Department of Chemistry, Biology and Biotechnology, University of Perugia and CIRCC, Via Elce di Sotto 8, 06123, Perugia, Italy.
[(L1)Au(μ-H)MCp][BF] complexes (M = Mo and W) featuring cavity-shaped tris-2-(4,4'-di--butylbi-phenylyl)phosphine (L1) have been isolated. The tungsten derivative showed a remarkably fast reactivity in photolytic hydride transfer to generate the mononuclear gold hydride (L1)AuH. Both bimetallic adducts trap Ag cations, forming unprecedented {Au(μ-H)M(μ-H)Ag} trimetallic assemblies with destabilized Au-M interactions.
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December 2024
Department of Chemistry, University of Houston, 3585 Cullen Blvd, Room 112, Houston, TX, 77204-5003, USA.
A series of heteroleptic copper(I) β-diketiminate triarylphosphine complexes is reported, having the general formula Cu(RNacNac)(PPh), where RNacNac is a substituted β-diketiminate and PPh is a triphenylphosphine derivative. A total of five different RNacNac ligands and three different triarylphosphines are used to assemble the nine complexes. The syntheses, X-ray crystal structures, cyclic voltammograms, and UV-vis absorption spectra of all compounds are described.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.
Synthesis and characterization of a thermally stable triarylphosphine radical cation, [P(8-Br-CH)][BArF] ([][BArF], BArF = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate), enabled by stabilization through -bromo-substituted naphthalenes, are described. Unlike previously reported phosphine radical cations that rely on sterically bulky substituents for stabilization, our approach leverages electronic stabilization via "through-space" radical delocalization. Single-crystal X-ray diffraction of [][BArF] reveals a tricapped tetrahedral geometry, resulting from the spatial proximity of the three bromine atoms to the phosphorus center, differentiated from the trigonal planar geometry observed in the previously reported triarylphosphine radical cations with sterically bulky substituents.
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