1,018 research outputs found
Ruthenacycles and Iridacycles as Transfer Hydrogenation Catalysts
In this review, we describe the synthesis and use in hydrogen transfer reactions of ruthenacycles and iridacycles. The review limits itself to metallacycles where a ligand is bound in bidentate fashion to either ruthenium or iridium via a carbon-metal sigma bond, as well as a dative bond from a heteroatom or an N-heterocyclic carbene. Pincer complexes fall outside the scope. Described are applications in (asymmetric) transfer hydrogenation of aldehydes, ketones, and imines, as well as reductive aminations. Oxidation reactions, i.e., classical Oppenauer oxidation, which is the reverse of transfer hydrogenation, as well as dehydrogenations and oxidations with oxygen, are described. Racemizations of alcohols and secondary amines are also catalyzed by ruthenacycles and iridacycles
One-step synthesis of a highly homogeneous SBA-NHC hybrid material: En route to single-site NHC-metal heterogeneous catalysts with high loadings
The one-step synthesis of a mesoporous silica of SBA type, functionalized with a 1-(2,6-diisopropylphenyl)-3-propyl-imidazolium (iPr2Ar-NHC-propyl) cation located in the pore channels, is described. This material was obtained by the direct hydrolysis and co-condensation of tetraethylorthosilicate (TEOS) and 1-(2,6-diisopropylphenyl)-3-[3-(triethoxysilyl)propyl]-imidazolium iodide in the presence of Pluronic P123 as a non-ionic structure-directing agent and aqueous HCl (37%) as an acid catalyst. Small-angle X-ray diffraction measurements, scanning and transmission electron microscopies, as well as dinitrogen sorption analyses revealed that the synthesized material is highly mesoporous with a 2D hexagonal arrangement of the porous network. 13C and 29Si CP-MAS NMR spectroscopy confirmed that the material contains intact iPr2Ar-NHC-propyl cations, which are covalently anchored via silicon atoms fused into the silica matrix. Moreover, comparison of the latter data with those of an analogous post-synthetic grafted SBA–NHC material allowed us to establish that, as expected, (i) it is most probably more homogeneous and (ii) it shows a more robust anchoring of the organic units. Finally, elemental mapping by energy dispersive X-ray spectroscopy in the scanning electron microscope demonstrated a very homogeneous distribution of the imidazolium units within the one-pot material, moreover with a high content. This study thus demonstrates that a relatively bulky and hydrophilic imidazolium unit can be directly co-condensed with TEOS in the presence of a structure-directing agent to provide in a single step a highly ordered and homogeneous mesoporous hybrid SBA–NHC material, possessing a significant number of cationic NHC sites
1-Benzyl-3-(1,2-diphenylethenyl)-1H-indole
In the title compound, C29H23N, the planar [maximum deviation from the least squares plane = 0.056 (1) Å] indole ring makes dihedral angles of 83.4 (4), 69.9 (1) and 59.9 (1)°, with the least-squares planes of three benzene rings. The molecular packing is stabilized by weak intermolecular C—H⋯π interactions
Ruthenacycles and Iridacycles as Catalysts for Asymmetric Transfer Hydrogenation and Racemisation
Ruthenacycles, which are easily prepared in a single step by reaction between enantiopure aromatic amines and [Ru(arene)Cl2]2 in the presence of NaOH and KPF6, are very good asymmetric transfer hydrogenation catalysts. A range of aromatic ketones were reduced using isopropanol in good yields with ee’s up to 98%. Iridacycles, which are prepared in similar fashion from [IrCp*Cl2]2 are excellent catalysts for the racemisation of secondary alcohols and chlorohydrins at room temperature. This allowed the development of a new dynamic kinetic resolution of chlorohydrins to the enantiopure epoxides in up to 90% yield and 98% enantiomeric excess (ee) using a mutant of the enzyme Haloalcohol dehalogenase C and an iridacycle as racemisation catalyst.
Correlates of quality of life of pre-obese and obese patients: a pharmacy-based cross-sectional survey
<p>Abstract</p> <p>Background</p> <p>The correlates of quality of life (QOL), as measured by the OSQOL questionnaire were investigated in a convenience sample of overweight patients recruited in pharmacies.</p> <p>Methods</p> <p>A convenience sample of patients with a Body Mass Index ≥ 28 kg/m<sup>2 </sup>were recruited in community-based pharmacies. Baseline characteristics and QOL dimensions (1-Physical state, 2-Vitality-desire to do things, 3-Relations with others, 4-Psychological state) were reported in self-completed questionnaires from which the risk of obtaining a low QOL was assessed for each dimension.</p> <p>Results</p> <p>QOL was inadequate for all dimensions in the 494 patients included in the study (median age = 61, 48% women, 21% professional persons/top executives). Older pre-obese and obese patients were more likely to report impaired physical functioning (OR = 2.02, 95%CI = [1.10-3.70]), but were less severely affected socially (OR = 0.32, 95%CI = [0.15-0.69]). Pre-obese and obese professional persons and top executives showed better physical capabilities (OR = 0.35, 95%CI = [0.15-0.81]) and increased vitality (OR = 0.47, 95%CI = [0.23-0.95]). Overall, men's psychological state was better than females' (OR = 0.46, 95%CI = [0.25-0.82]). A body-mass index ≥ 35 kg/m<sup>2 </sup>was significantly associated with poorer QOL scores on physical, relational and psychological dimensions.</p> <p>Conclusion</p> <p>Our data highlighted the influence of the severity of excess weight, gender, age and socioeconomic status on QOL. These factors should be taken into account when interpreting QOL in pre-obese and obese persons.</p
Asthma patients' self-reported behaviours toward inhaled corticosteroids
SummaryBackgroundPatient adherence to recommended use of ICS is questionable in asthma, with irregular use or interruptions occurring frequently. Factors explaining discontinuation of controller therapy could orientate interventions. The characteristics of patients with interruptions of inhaled corticosteroids (ICSs), intentional or accidental, were investigated.MethodsAsthma patients regularly prescribed ICS by GPs (Cegedim network) were included. Patients' characteristics and behaviours toward ICS (accidental/intentional interruptions, less frequent use of ICS and change in dosing) were identified from self-report questionnaires, and linked to data prescription database. Interrelations between declared behaviours toward ICS were studied with a Multiple Component Analysis (MCA) and the correlates of ICS interruptions were identified.ResultsDuring the past 3 months, 31.6% of 204 patients (mean age: 53.8 years, females: 59.3%) intentionally interrupted ICS when feeling better, 25.4% forgot ICS and 18.3% deliberately changed the doses. A quarter of patients considered constant use of respiratory medicines as unhealthy. MCA revealed that intentional, accidental interruptions and less frequent use of ICS were closely correlated. Risk of intentional interruption was increased when patients considered constant use of respiratory therapy to be unhealthy (OR=3.36, 95%CI=[1.47–7.66]). Conversely, risk was significantly lower when ICS was associated or combined with another controller (OR=0.24, 95%CI=[0.08–0.73]), compared to ICS in monotherapy. Less frequent interruptions were observed in patients older than 65 (OR=0.35, 95%CI=[0.13–0.89]).ConclusionsOur study suggests that discontinuation of use of controllers is associated with other inadequate behaviours or beliefs about inhaled controllers. Efforts should be targeted at patients' perceptions and behaviours toward controller therapy
Pseudo-tetrahedral semi-sandwich cycloruthenated compounds: <sup>1</sup>H NMR data and DFT-calculations about the racemisation process of the ruthenium atom
Changes in immune activation in the T Cell compartments of HIV HCV coinfected patients during PEG IFN RBV treatment
A multinuclear 1H, 13C and 11B solid-state MAS NMR study of 16- and 18-electron organometallic ruthenium and osmium carborane complexes
YesThe first 1H, 13C, 31P and 11B solid state MAS NMR studies of electron-
deficient carborane-containing ruthenium and osmium
complexes [Ru/Os(p-cym)(1,2-dicarba-closo-dodecaborane-1,2-
dithiolate)] are reported. The MAS NMR data from these 16-electron
complexes are compared to those of free carborane-ligand
and an 18-electron triphenylphosphine ruthenium adduct, and
reveal clear spectral differences between 16- and 18-electron
organometallic carborane systems in the solid state.We thank the Swiss National Science Foundation (grant no. PA00P2-145308 to NPEB), the ERC (grant no. 247450 to PJS), EPSRC (grant no. EP/F034210/1) and EC COST Action CM1105 for support. JVH thanks EPSRC and the University of Warwick for partial funding of the solid state NMR infrastructure at Warwick, and acknowledges additional support obtained through Birmingham Science City: Innovative Uses for Advanced Materials in the Modern World (West Midlands Centre for Advanced Materials Project 2), with support from Advantage West Midlands (AWM) and partial funding by the European Regional Development Fund (ERDF)
Green conditions for the Suzuki reaction using microwave irradiation and a new HNT- supported ionic liquid-like phase (HNT-SILLP) catalyst
A new catalytic system based on modified halloysite nanotubes was employed in the Suzuki reaction under microwave irradi- ation. A set of solvents, times and bases was screened and the best experimental conditions were obtained when the reactions were carried out for 10 min in water\u2013ethanol at 120 \ub0C in presence of K2CO3 as base. Good recyclability was observed. The new catalytic system was employed using either 1 mol% or 0.1 mol%. The palladium catalyst displayed good activity, allowing the synthesis of several biphenyl compounds in high yield working with only 0.1 mol% palladium loading. The application of mi- crowave irradiation decreased the reaction time and also improved conversion with respect to traditional heating
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