Study of the reaction of Rh(acac)(CO)2 with alkenes in polyethylene films under high-pressure hydrogen and the Rh-catalysed hydrogenation of alkenes

Redox Properties of Mononuclear Dicarbonyl and Carbonylphosphine Rhodium (I) Complexes Containing β-diketonate Ligands

The redox properties of mononuclear dicarbonyl and carbonylphosphine rhodium (I) complexes (CO)(L)Rh(RC(O)CHC(O)R’) with chelate β-diketonate ligands (L = CO, PPh3; R, R’ = Me, Ph; CF3, C4H3S) were studied by electrochemical methods at platinum, glassed carbon and dropping mercury electrodes in acetonitrile. Schemes of their redox reactions were established

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.

High-pressure-low-temperature cryostat designed for use with fourier transform infrared spectrometers and time-resolved infrared spectroscopy

The design for a new high-pressure-low-temperature infrared (IR) cell for performing experiments using conventional Fourier transform infrared or fast laser-based time-resolved infrared spectroscopy, in a range of solvents, is described. The design builds upon a commercially available compressor and cold end (Polycold PCC(®) and CryoTiger(®)), which enables almost vibration-free operation, ideal for use with sensitive instrumentation. The design of our cell and cryostat allows for the study of systems at temperatures from 77 to 310 K and at pressures up to 250 bar. The CaF2 windows pass light from the mid-IR to the ultraviolet (UV), enabling a number of experiments to be performed, such as Raman, UV-visible absorption spectroscopy, and time-resolved techniques where sample excitation/probing using continuous wave or pulsed lasers is required. We demonstrate the capabilities of this cell by detailing two different applications: (i) the reactivity of a range of Group V-VII organometallic alkane complexes using time-resolved spectroscopy on the millisecond timescale and (ii) the gas-to-liquid phase transition of CO2 at low temperature, which is applicable to measurements associated with transportation issues related to carbon capture and storage.

Synthesis characterization and hydroformylation activity of new mononuclear rhodium(I) compounds incorporated with polar-group functionalized phosphines

A first effort employing a range of polar-group functionalized phosphines (L 1 –L 7 ) to design mononuclear Rh(I) compounds of [Rh(quin-8-O)(CO)(L)] (quin-8-O = 8-hydroxy quinolate) is described. The reaction of a Rh(I) precursor [Rh(μ-Cl)(CO)2]2 with 8-hydroxyquinoline in the presence of a base followed by phosphines (L 1 –L 7 ) produced only a single isomer of [Rh(quin-8-O)(CO)(L)] compounds (1–7) with pendant, i.e. non-bonded, polar-groups (includes carboxyl, hydroxyl and formyl). A relationship between Δgd31P chemical shifts and the ν(C≡O) was derived to evaluate and explain the σ-donor properties of these phosphines with respect to the electronic properties of the polar groups and the extent of π-back-bonding to the CO group. These mononuclear Rh(I)-Phosphines were investigated as catalysts in the hydroformylation of 1-hexene and cyclohexene in aqueous two-phase and single-phase solvent systems. The Rh(I) catalysts with strong σ-donor and hydrophilic phosphines provided better yields and selectivities for the hydroformylation products, which is a reverse trend compared to literature reports. When the Rh(I) compounds contained strong σ-donor phosphines, the π-acceptor properties of the pyridine ring of 8-hydroxyquinolate were found to be beneficial for the facile cleavage of the CO group during hydroformylation, and additionally, to improve the kinetic stability of catalysts.