Refinement of the crystal structure of acetylacetonatodicarbonylrhodium(I)

Structure and bonding in rhodium coordination compounds: a 103Rh solid-state NMR and relativistic DFT study

This study demonstrates the application of 103Rh solid-state NMR (SSNMR) spectroscopy to inorganic and organometallic coordination compounds, in combination with relativistic density functional theory (DFT) calculations of 103Rh chemical shift tensors and their analysis with natural bond orbital (NBO) and natural localized molecular orbital (NLMO) protocols, to develop correlations between 103Rh chemical shift tensors, molecular structure, and Rh-ligand bonding. 103Rh is one of the least receptive NMR nuclides, and consequently, there are very few reports in the literature. We introduce robust 103Rh SSNMR protocols for stationary samples, which use the broadband adiabatic inversion-cross polarization (BRAIN-CP) pulse sequence and wideband uniform-rate smooth-truncation (WURST) pulses for excitation, refocusing, and polarization transfer, and demonstrate the acquisition of 103Rh SSNMR spectra of unprecedented signal-to-noise and uniformity. The 103Rh chemical shift tensors determined from these spectra are complemented by NBO/NLMO analyses of contributions of individual orbitals to the 103Rh magnetic shielding tensors to understand their relationship to structure and bonding. Finally, we discuss the potential for these experimental and theoretical protocols for investigating a wide range of materials containing the platinum group elements.

Open-Cage Fullerene as a Macrocyclic Ligand for Na, Pt, and Rh Metal Complexes

An open-cage [60]fullerene derivative was prepared through Malaprade oxidation of a vicinal triol moiety as the key step. Above the 17-membered orifice, there is one carboxyl group. Three ketone carbonyl groups and one lactone carbonyl group are located on the rim of the orifice. The carboxylic and carbonyl oxygen atoms around the orifice act as strong polydentate ligands for a sodium ion. These oxygen atoms also react with [Rh(CO)2Cl]2 to form various isomeric rhodium complexes with comparable stability. The fullerene C═C bond on the rim of the orifice forms a stable platinum complex when treated with Pt(PPh3)4. Single crystal X-ray diffraction data reveal that one of the carboxylic oxygen atoms above the orifice forms a H-bond with the water molecule trapped in the cage.

Density functional theory calculations of Rh-β-diketonato complexes

Density functional theory results on the geometry, energies and charges of selected Rh-β-diketonato reactants, products and transition states.

(Benzoyl-acetonato-κ(2) O,O')dicarbonyl-rhodium(I)

In the title compound, [Rh(C10H9O2)(CO)2], a distorted square-planar coordination geometry is observed around the Rh(I) atom, formed by the O atoms of the bidentate ligand and two C atoms from the carbonyl ligands. The Rh(I) atom is displaced from the plane through the surrounding atoms by 0.017 Å. In the crystal, C-H⋯O inter-action is observed between a methyl group of the bidentate ligand and a carbonyl O atom. Metallophilic inter-actions [3.308 (3) and 3.461 (3) Å] between neighbouring Rh(I) atoms are encountered in the crystal, resulting in the formation of a metal chain along the b-axis direction.

Extended X-ray absorption fine structure (EXAFS) characterisation of the hydroformylation of oct-1-ene by dilute Rh–PEt3catalysts in supercritical carbon dioxide

Dilute EXAFS characterisation has been used to elucidate species involved during the course of the 3 mM Rh-catalysed hydroformylation of oct-1-ene in scCO(2); significant metal clustering occurs with a Rh:P ratio of 1:1 but at a 1:3 ratio, metal clustering is not detected, with the presence of monomer species only.