On the Functional Group Tolerance of Ester Hydrogenation and Polyester Depolymerisation Catalysed by Ruthenium Complexes of Tridentate Aminophosphine Ligands.

The synthesis of a range of phosphine-diamine, phosphine-amino-alcohol, and phosphine-amino-amide ligands and their ruthenium(II) complexes are reported. Five of these were characterised by X-ray crystallography. The activities of this collection of catalysts were initially compared for the hydrogenation of two model ester hydrogenations. Catalyst turnover frequencies up to 2400 h(-1) were observed at 85 °C. However, turnover is slow at near ambient temperatures. By using a phosphine-diamine Ru(II) complex, identified as the most active catalyst, a range of aromatic esters were reduced in high yield. The hydrogenation of alkene-, diene-, and alkyne-functionalised esters was also studied. Substrates with a remote, but reactive terminal alkene substituent could be reduced chemoselectively in the presence of 4-dimethylaminopyridine (DMAP) co-catalyst. The chemoselective reduction of the ester function in conjugated dienoate ethyl sorbate could deliver (2E,4E)-hexa-2,4-dien-1-ol, a precursor to leaf alcohol. The monounsaturated alcohol (E)-hex-4-en-1-ol was produced with reasonable selectivity, but complete chemoselectivity of C=O over the diene is elusive. High chemoselectivity for the reduction of an ester over an alkyne group was observed in the hydrogenation of an alkynoate for the first time. The catalysts were also active in the depolymerisation reduction of samples of waste poly(ethylene terephthalate) (PET) to produce benzene dimethanol. These depolymerisations were found to be poisoned by the ethylene glycol side product, although good yields could still be achieved.

Insomnia in long-term care facilities: a comparison of seven European countries and Israel: the Services and Health for Elderly in Long TERm care study.

OBJECTIVES: To assess insomnia and its correlates as part of the Services and Health for Elderly in Long TERm care (SHELTER) study, funded by the 7th Framework Programme of the European Union. DESIGN: Cross-cultural investigation. SETTING: Long-term care facilities (LTCFs) in eight European countries (Czech Republic, France, Finland, Germany, England, the Netherlands, Italy) and one non-European country (Israel). PARTICIPANTS: Elderly residents (N = 4,156) of 57 LTCFs. MEASUREMENTS: Information on insomnia, age, sex, activities of daily living (ADLs), cognitive status, depression, major stressful life events, physical activity, fatigue, pain, and sleep medication use was extracted from the International Resident Assessment Instrument (interRAI)LTCF instrument. Rates of insomnia and its correlates were analyzed. Multivariate logistic regression was used to assess factors associated with insomnia, controlling for demographic variables. RESULTS: The prevalence of insomnia was 24% (range 13-30%), with significant differences between countries (P < .001). More insomnia complaints were reported in older than younger residents (P < .001). Higher rates of insomnia were associated with hypnosedatives and depression in all countries (P < .001) and with stressful life events, fatigue, and pain in most countries (P < .001). No associations were found between insomnia and ADLs, physical activity, or cognitive status. Age, depression, stressful life events, fatigue, pain and hypnosedatives were independent significant predictors of insomnia, controlling for all other variables and for country. CONCLUSION: Hypnosedatives and depression were strong predictors of insomnia beyond cultural differences. Overall, psychosocial variables were more strongly related to insomnia than functional and mental capacities.

Highly enantioselective hydrogenation and transfer hydrogenation of cycloalkyl and heterocyclic ketones catalysed by an iridium complex of a tridentate phosphine-diamine ligand.

Ir complexes of chiral phosphine-diamine ligands catalyse the hydrogenation and transfer hydrogenation of aryl-piperidin-4-yl methanones, and ketones bearing both an aryl group and secondary alkyl substituent with up to 98% e.e., and with substrate to catalyst ratios of up to 4000.

Convenient and improved protocols for the hydrogenation of esters using Ru catalysts derived from (P,P), (P,N,N) and (P,N,O) ligands.

An improved protocol where a pre-cursor, [Ru(Cl)(2)(NBD)(Py)(2)], is treated with ligands to form [RuCl(2)(bidentate ligand)(diamine)] pre-catalysts for ester hydrogenation is reported. This family of catalysts, as well as a range of ruthenium complexes of tridentate P^N^X (X = NR(2), OH) ligands have been investigated in the hydrogenation of aromatic esters. A range of aromatic esters can be hydrogenated in high yields at temperatures between 30 °C and 100 °C.

Gas phase kinetic and quantum chemical studies of the reactions of silylene with the methylsilanes. Absolute rate constants, temperature dependences, RRKM modelling and potential energy surfaces.

Time resolved studies of silylene, SiH2, generated by the 193 nm laser flash photolysis of phenylsilane, have been carried out to obtain rate coefficients for its bimolecular reactions with methyl-, dimethyl- and trimethyl-silanes in the gas phase. The reactions were studied over the pressure range 3-100 Torr with SF6 as bath gas and at five temperatures in the range 300-625 K. Only slight pressure dependences were found for SiH2+MeSiH3(485 and 602 K) and for SiH2+Me2SiH2(600 K). The high pressure rate constants gave the following Arrhenius parameters: [TABLE: SEE TEXT]. These are consistent with fast, near to collision-controlled, association processes. RRKM modelling calculations are consistent with the observed pressure dependences (and also the lack of them for SiH2+Me3SiH). Ab initio calculations at both second order perturbation theory (MP2) and coupled cluster (CCSD(T)) levels, showed the presence of weakly-bound complexes along the reaction pathways. In the case of SiH2+MeSiH3 two complexes, with different geometries, were obtained consistent with earlier studies of SiH2+SiH4. These complexes were stabilised by methyl substitution in the substrate silane, but all had exceedingly low barriers to rearrangement to product disilanes. Although methyl groups in the substrate silane enhance the intrinsic SiH2 insertion rates, it is doubtful whether the intermediate complexes have a significant effect on the kinetics. A further calculation on the reaction MeSiH+SiH4 shows that the methyl substitution in the silylene should have a much more significant kinetic effect (as observed in other studies).