307 research outputs found
Analysis induced reduction of a polyelectrolyte
The polymer, poly(diallyldimethylammonium chloride) (PDDA), is shown to undergo chemical change via a reduction mechanism during X-ray analysis. Examination of the N 1s spectrum of PDDA shows a time dependence on the degree of reduction, together with clear amplification of the extent of reduction through the charge compensation system and X-ray irradiation
Massachusetts model system for educator evaluation
The synthesis and characterization of a series of platinum and palladium complexes containing a secondary borane Z-class ligand supported by 2-mercaptopyridine heterocycles is reported herein. Addition of 2 equiv of Na[H2B(mp)2] to [Pt(ÎŒ-Cl)(COEOMe)]2 (where COEOMe = 8-methoxycyclooct-4-en-1-ide) in the presence of 2 equiv of a tertiary phosphine (PR3 = PPh3, PCy3, PCyp3, P(o-tol)3, PPh2(o-tol), PPh2(2-(3-methyl)indolyl)) leads to the formation of the complexes [Pt{Îș3-S,B,S-HB(mp)2}(PR3)] (1â6). Addition of 2 equiv of Na[H2B(mp)2] to [Pd(ÎŒ-Cl)(COEOMe)]2 in the presence of 2 equiv of a tertiary phosphine (PR3 = PPh3, PCy3, PCyp3, PPh2(o-tol)) leads to the formation of the complexes [Pd{Îș3-S,B,S-HB(mp)2}(PR3)] (7â10). It was also demonstrated that the synthesis of the palladium complex 7 could be achieved from the palladium precursor [PdCl(Me)(COD)] (where COD = 1,5-cyclooctadiene) as an alternative synthetic strategy. In the above reactions, either the COEOMe fragment or the methyl fragment serves to act as a âhydride acceptorâ facilitating the ultimate transformation of the borohydride-based ligand [H2B(mp)2]â to the corresponding secondary borane Îș3-S,B,S coordinated HB(mp)2 pincer ligand. The complexes [Pd{Îș3-S,B,S-HB(mp)2}(PR3)] and [Pt{Îș3-S,B,S-HB(mp)2}(PR3)] are rare examples of metalâborane complexes where one hydrogen substituent remains at the boron center. These compounds have particularly short palladiumâ and platinumâboron distances, the shortest of the structurally characterized compounds being 2.067(6) Ă
for [Pd{Îș3-S,B,S-HB(mp)2}(PPh2(o-tol))] and 2.076(10) Ă
for [Pt{Îș3-S,B,S-HB(mp)2}(PCy3)], respectively (the shorter distances of two independent complexes in the unit cells of both structures)
Boronic acids for functionalisation of commercial multi-layer graphitic material as an alternative to diazonium salts
A novel radical-based functionalisation strategy for the synthesis of functionalised commercially obtained plasma-synthesised multi-layer graphitic material (MLG) is presented herein. 4-(trifluoromethyl)phenyl boronic acid was utilised as a source of 4-(trifluoromethyl)phenyl radicals to covalently graft upon the graphitic surface of MLG. Such a methodology provides a convenient and safer route towards aryl radical generation, serving as a potential alternative to hazardous diazonium salt precusors. The structure and morphology of the functionalised MLG (Arf-MLG) has been characterised using XPS, Raman, TGA, XRD, SEM, TEM and BET techniques. The XPS quantitative data and Raman spectra provide evidence of successful covalent attachment of 4-(trifluoromethyl)phenyl groups to MLG
Identifying the routes by which children view pornography online: implications for future policy-makers seeking to limit viewing
Report of Expert Panel for DCM
Expansion of the ligand knowledge base for chelating P,P-donor ligands (LKB-PP)
[Image: see text] We have expanded the ligand knowledge base for bidentate P,P- and P,N-donor ligands (LKB-PP, Organometallics2008, 27, 1372â1383) by 208 ligands and introduced an additional steric descriptor (nHe(8)). This expanded knowledge base now captures information on 334 bidentate ligands and has been processed with principal component analysis (PCA) of the descriptors to produce a detailed map of bidentate ligand space, which better captures ligand variation and has been used for the analysis of ligand properties
Oleophobic composite films based on multi-layer graphitic scaffolding
A new oleophobic composite material synthesised by utilising plasma-exfoliated multi-layered graphitic (MLG) material as scaffolding is presented herein. The composite consisted of a polyelectrolyte/fluorosurfactant complex derived from polydiallyldimethylammonium chloride (PDDA) and sodium perfluorooctanoate (PFO) and was used to prepare free-standing MLG composite films
Advance Statements for Black African and Caribbean people (AdStAC):protocol for an implementation study
Background
Advance Choice Documents (ACDs) have been recommended for inclusion in new mental health legislation for England and Wales. This is based on evidence-based interventions to reduce compulsory psychiatric admission, with particular benefit for Black people, whose rates of compulsory psychiatric admission in the UK are over three times higher than those of White British people. Our aim was to explore potential barriers and enablers to effective implementation of ACDs for use by Black people with previous experience of compulsory admission.
Methods
Seven online and in-person workshops were held with: Black service users who had previously been compulsorily admitted, carers/supporters of Black service users, and mental health professionals. Workshops were recorded and transcribed.
Results
Inductive analysis was employed to identify recommendations and determine where there was a lack of consensus. Thematic analysis identified key themes of âpeopleâ, âprocessâ and âpowerâ pertaining to ACD implementation.
Discussion
Our results reinforce the need for independent facilitation for ACD creation and their potential to empower Black service users in relation to their care. They suggest that explicit acknowledgement of, and time spent listening to, the historical and individual poor experiences that underlie the treatment preferences Black people express are important aspects of ACD creation
Discrete wetland groundwater discharges revealed with a three-dimensional temperature model and botanical indicators (Boxford, UK)
Wetlands provide unique goods and services, as habitats of high biodiversity. Hydrology is the principal control on wetland functioning; hence, understanding the water source is fundamental. However, groundwater inflows may be discrete and easily missed. Research techniques are required with low cost and minimal impact in sensitive settings. In this study, the effectiveness of using a three-dimensional (3D) temperature model and botanical indicators to characterise groundwater discharge is explored at the CEH (Centre for Ecology and Hydrology) River Lambourn Observatory, Boxford, UK. This comprises a 10 ha lowland riparian wetland, designated for its scientific interest and conservation value. Temperature data were collected in winter at multiple depths down to 0.9 m over approximately 3.6 ha and transformed into a 3D model via ordinary kriging. Anomalous warm zones indicated distinct areas of groundwater upwelling which were concurrent with relic channel structures. Lateral heat propagation from the channels was minimal and restricted to within 5â10 m. Vertical temperature sections within the channels suggest varying degrees of groundwater discharge along their length. Hydrochemical analysis showed that warmer peat waters were akin to deeper aquifer waters, confirming the temperature anomalies as areas of groundwater discharge. Subsequently, a targeted vegetation survey identified Carex paniculata as an indicator of groundwater discharge. The upwelling groundwater contains high concentrations of nitrate which is considered to support the spatially restricted growth of Carex paniculata against a background of poor fen communities located in reducing higher-phosphate waters
Room Temperature Hydrogenation of CO2 Utilizing a Cooperative Phosphorus PyridoneâBased Iridium Complex
The synthesis, characterization and application of a new complex, [Ir(Îș2-P,N-6-DCyPon*)(COD)] (1), where 6-DCyPon* is the anionic species, 6-dicyclohexylphosphino-2-oxo-pyridinide, is reported herein. Complex 1 was found to be an active catalyst in the hydrogenation of CO2 at room temperature. The ligand, 6-DCyPon*, is derived via deprotonation of a novel pro-ligand, 6-DCyPon (6-dicyclohexylphosphino-2-pyridone) during the synthesis of 1. The ligand is shown to participate within the reversible hydrogenation of 1, via a cooperative process, in which the species, [IrH3(Îș2-P,N-6-DCyPon)(COD)] (2), was spectroscopically characterized, where 1 reacts with two equivalents of H2
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