A homologous family of low-coordinate complexes of the formulation trans-[M(2,2'-biphenyl)(PR ) ][BAr ] (M=Rh, Ir; R=Ph, Cy, iPr, iBu) has been prepared and extensively structurally characterised. Enabled through a comprehensive set of solution phase (VT H and P NMR spectroscopy) and solid-state (single crystal X-ray diffraction) data, and analysis in silico (DFT-based NBO and QTAIM analysis), the structural features of the constituent agostic interactions have been systematically interrogated. The combined data substantiates the adoption of stronger agostic interactions for the Ir compared to Rh complexes and, with respect to the phosphine ligands, in the order PiBu >PCy >PiPr >PPh . In addition to these structure-property relationships, the effect of crystal packing on the agostic interactions was investigated in the tricyclohexylphosphine complexes. Compression of the associated cations, through inclusion of a more bulky solvent molecule (1,2-difluorobenzene vs. CH Cl ) in the lattice or collection of data at very low temperature (25 vs. 150 K), lead to small but statistically significant shortening of the M-H-C distances.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5901041 | PMC |
| http://dx.doi.org/10.1002/chem.201705990 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Isostructural Dy(III) and Er(III) complexes [L12Ln(H2O)5][I]3·L12·(CH2Cl2) (Ln = Dy (1), Er (3)) and [L22Ln(H2O)5][I]3·L22·(CH2Cl2)2 (Ln = Dy (2), Er (4)), with distorted pentagonal bipyramidal geometry (D5h) around the central metal were synthesized by utilizing two bulky phosphonamide ligands, adamantyl phosphonamide, (Ad)P(O)(NHiPr)2 (L1) and carbazolyl phosphoramide (Cz)P(O)(NHiPr)2 (L2). The resultant complexes were investigated for their magnetic properties in order to elucidate the impact of modification of the coordinating P-O bond environment either by increasing steric bulk and/or introduction of a third P-N bond at the central phosphorus atom. Magnetic studies revealed substantial energy barriers (Ueff) of 640 K and 560 K for Dy compounds 1 and 2, respectively, rendering them as some of the best-performing air-stable SIMs amongst the class of SIMs with D5h symmetry.
View Article and Find Full Text PDFCross-Dehydrogenative Coupling of Secondary Amines with Silanes Catalyzed by Agostic Iridium-NSi Species.
Inorg Chem
December 2024
Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Facultad de Ciencias, Universidad de Zaragoza - CSIC, 50009 Zaragoza, Spain.
An active catalytic system for the cross-dehydrogenative coupling (CDC) of a wide range of secondary amines with silanes is reported. The iridium(III) derivatives [Ir(H)(X)(κ-NSi)(L)] (NSi = {4,8-dimethylquinoline-2-yloxy}dimethylsilyl; L = coe, X = Cl, ; L = coe, X = OTf, ; L = PCy, X = Cl, ; L = PCy X = OTf, ), which are stabilized by a weak yet noticeable Ir···H-C agostic interaction between the iridium and one of the C-H bonds of the 8-Me substituent of the NSi ligand, have been prepared and fully characterized. These species have proven to be effective catalysts for the CDC of secondary amines with hydrosilanes.
View Article and Find Full Text PDFRuthenium-Catalyzed α-Regioselective Hydroboration of Allenes.
Angew Chem Int Ed Engl
December 2024
Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077, Hong Kong SAR, China.
Hydroboration of allenes is powerful and atom-economic approach to the synthesis of organoboranes, such as the highly versatile allylboranes. However, regarding regiocontrol, existing methods uniformly deliver the boron functionality to the less hindered β- or γ-position, but not the α-position. The latter is particularly challenging for allenes with substantial steric difference between the two terminals and lacking electronic bias (e.
View Article and Find Full Text PDFT-shaped 14 Electron Rhodium Complexes: Potential Active Species in C-H Activation.
Angew Chem Int Ed Engl
December 2024
Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
Two T-shaped 14-electron rhodium complexes 2 a and 2 b, "framed" and thus stabilized by PNP pincer ligands have been synthesized. The bis(t-butyl)phosphine derived PNP-rhodium complex 2 a was isolated from pentane as the more stable cyclometalated Rh(III) hydrido complex and found to be in equilibrium with the T-shaped 14e Rh(I) complex 2 aT which itself could be directly crystallized upon change of the solvent. The cyclometallation is suppressed using an adamantyl substituted PNP ligand to give the analogous T-shaped Rh(I) species 2 b, stabilized through an agostic interaction with one of the adamantyl C-Hs.
View Article and Find Full Text PDFElectron Density and Molecular Orbital Analyses of the Nature of Bonding in the η-CCH Agostic Rhodium Complexes Preceding the C-C and C-H Bond Cleavages.
Molecules
October 2024
Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel.
In our recent work, we revisited C-H and C-C bond activation in rhodium (I) complexes of pincer ligands PCP, PCN, PCO, POCOP, and SCS. Our findings indicated that an η-CCH agostic intermediate acts as a common precursor to both C-C and C-H bond activation in these systems. We explore the electronic structure and bonding nature of these precleavage complexes using electron density and molecular orbital analyses.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!