996 resultados para electroanalytical chemistry


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English: The present thesis describes the synthesis of 1,1’-ferrocendiyl-based pyridylphosphine ligands, the exploration of their fundamental coordination chemistry and preliminary experiments with selected complexes aimed at potential applications. One main aspect is the synthesis of the bidentate ferrocene-based pyridylphosphine ligands 1-(Pyrid-2-yl)-1’-diphenylphosphinoferrocene, 1-(Pyrid-3-yl)-1’-diphenylphosphinoferrocene and 1-[(Pyrid-2-yl)methyl]-1’-diphenylphosphinoferrocene. A specific feature of these ligands is the ball-bearing like flexibility of the ferrocenebased backbone. An additional flexibility element is the rotation around the C–C single bonds. Consequently, the donor atoms can realise a wide range of positions with respect to each other and are therefore able to adapt to the coordination requirements of different metal centres. The flexibility of the ligand also plays a role in another key aspect of this work, which concerns the coordination mode, i. e. bridging vs. chelating. In addition to the flexibility, also the position of the donor atoms to each other is important. This is largely affected by the position of the pyridyl nitrogen (pyrid-2-yl vs. pyrid-3-yl) and the methylen group in 1-[(Pyrid-2-yl)methyl]-1’-diphenylphosphinoferrocene. Another interesting point is the combination of a soft phosphorus donor atom with a harder nitrogen donor atom, according to the HSAB principle. This combination generates a unique binding profile, since the pi-acceptor character of the P site is able to stabilise a metal centre in a low oxidation state, while the nitrogen sigma-donor ability can make the metal more susceptible to oxidative addition reactions. A P,N-donor combination can afford hemilabile binding profiles, which would be ideal for catalysis. Beyond 1,2-substituted ferrocene derivatives, which are quite successful in catalytic applications, 1,1’-derivatives are rather underrepresented. While a low-yield synthetic pathway to 1-(Pyrid-2-yl)-1’-diphenylphosphinoferrocene was already described in the literature [I. R. Butler, Organometallics 1992, 11, 74.], it was possible to find a new, improved and simplified synthetic pathway. Both other ligands were unknown prior to this work. Satisfactory results in the synthesis of 1-(Pyrid-3-yl)-1’-diphenylphosphinoferrocene could be achieved by working in analogy to the new synthetic procedure for 1-(Pyrid-2-yl)-1’-diphenylphosphinoferrocene. The synthesis of 1-[(Pyrid-2-yl)methyl]-1’-diphenylphosphinoferrocene has been handled by the group of Prof. Petr Stepnicka from Charles University, Prague, Czech Republic. The synthesis of tridentate ligands with an analogous heterodentate arrangement, was investigated briefly as a sideline of this study. The major part of this thesis deals with the fundamental coordination chemistry towards transition metals of the groups 10, 11 and 12. Due to the well-established catalytic properties of analogous palladium complexes, the coordination chemistry towards palladium (group 10) is of particular interest. The metals zinc and cadmium (group 12) are also of substantial importance because they are redox-inert in their divalent state. This is relevant in view of electrochemical investigations concerning the utilisation of the ligands as molecular redox sensors. Also mercury and the monovalent metals silver and gold (group 11) are included because of their rich coordination chemistry. It is essential to answer questions concerning aspects of the ligands’ coordination mode bearing in mind the HSAB principle.

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The use of perturbation and power transformation operations permits the investigation of linear processes in the simplex as in a vectorial space. When the investigated geochemical processes can be constrained by the use of well-known starting point, the eigenvectors of the covariance matrix of a non-centred principal component analysis allow to model compositional changes compared with a reference point. The results obtained for the chemistry of water collected in River Arno (central-northern Italy) have open new perspectives for considering relative changes of the analysed variables and to hypothesise the relative effect of different acting physical-chemical processes, thus posing the basis for a quantitative modelling

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The identification of compositional changes in fumarolic gases of active and quiescent volcanoes is one of the most important targets in monitoring programs. From a general point of view, many systematic (often cyclic) and random processes control the chemistry of gas discharges, making difficult to produce a convincing mathematical-statistical modelling. Changes in the chemical composition of volcanic gases sampled at Vulcano Island (Aeolian Arc, Sicily, Italy) from eight different fumaroles located in the northern sector of the summit crater (La Fossa) have been analysed by considering their dependence from time in the period 2000-2007. Each intermediate chemical composition has been considered as potentially derived from the contribution of the two temporal extremes represented by the 2000 and 2007 samples, respectively, by using inverse modelling methodologies for compositional data. Data pertaining to fumaroles F5 and F27, located on the rim and in the inner part of La Fossa crater, respectively, have been used to achieve the proposed aim. The statistical approach has allowed us to highlight the presence of random and not random fluctuations, features useful to understand how the volcanic system works, opening new perspectives in sampling strategies and in the evaluation of the natural risk related to a quiescent volcano

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Seleccionado en la convocatoria: Licencias por estudios destinadas a funcionarios docentes no universitarios, Gobierno de Aragón 2009-10

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These documents show the outcomes of surveys conducted by David Read in the School of Chemistry to find out about our students' expectations and perceptions of feedback, with a view to enhancing our provision and ensuring that student learning is maximised.

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This document outlines the material covered by the main UK exam board specifications at A-level in chemistry. This is for the A-level taught up until and including June 2009 (i.e. relevant to undergraduates arriving at university in October 2009).

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This document is a review of the content of the A-level Chemistry specifications from the main UK exam boards (Scottish highers not included - sorry!). These A-level specifications commenced teaching in September 2008. Students entering university in 2010 will have studied the new A-levels, and this document is intended to help academics to identify what students will have covered. The document also contains a summary of discussions which took place between teachers and academics at our annual Post-16 teachers' day in June 2010 regarding the nature of the 2010 intake and their capabilities in chemistry. Please inform us of any errors or typos that you spot and we'll update the document. LAST UPDATE at 13:15 on Aug 27th 2010.

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This presentation has been modified by a B.Sc final year project student to promote chemistry as a degree and a career option for youngsters. The original presentation was produced by the Biological and Medicinal Chemistry Sector or the Royal Society of Chemistry. The project student has polished the slides to make them more appealing to today's A-level students. She has also evaluated the impact of her work. A summary of her report will be added in due course.

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These images have been created for use in Physical Chemistry slides to overcome copyright issues when recording lectures. They are free to use without restrictions, although we do not accept responsibility for any errors in the images. Please let us know if you spot any errors, though! Please view the catalogue document for a description of the images. We intend to add to this collection on an ongoing basis. Check back for updates. Current content - 43 images. Last update: August 31st 2011

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These lectures are designed to show new students different lecturing styles they will encounter at Southampton University. This lecture is in the style of 'Chalk and Talk'. The lectures also teach students some of the fundamental parts of physics which are relevant to the Physical Chemistry course. This will be particularly useful for students who have forgotten their GCSE physics! To view the videos, download the zip file and 'extract' the contents by right clicking on the folder. Then double click on the file 'Play video.html'. Note that the video has been compressed heavily so it can be downloaded, which means there is a slight loss in quality. If you have a problem with this, please e-mail David Read (d.read@soton.ac.uk). NOTE: YOU MUST EXTRACT THE ZIP FOLDER BEFORE CLICKING ON 'Play video.html' OTHERWISE IT WON'T WORK.

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These lectures are designed to show new students different lecturing styles they will encounter at Southampton University. This lecture is delivered using a Tablet PC. These lectures also teach students some of the fundamental parts of physics which are relevant to the Physical Chemistry course. This will be particularly useful for students who have forgotten their GCSE physics! To view the videos, download the zip file and 'extract' the contents by right clicking on the folder. Then double click on the file 'Play video.html'. Note that the video has been compressed heavily so it can be downloaded, which means there is a slight loss in quality. If you have a problem with this, please e-mail David Read (d.read@soton.ac.uk). NOTE: YOU MUST DOWNLOAD AND EXTRACT THE ZIP FOLDER BEFORE CLICKING ON 'Play video.html' OTHERWISE IT WON'T WORK.

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These lectures are designed to show new students different lecturing styles they will encounter at Southampton University. This lecture is delivered using PowerPoint. These lectures also teach students some of the fundamental parts of physics which are relevant to the Physical Chemistry course. This will be particularly useful for students who have forgotten their GCSE physics! To view the videos, download the zip file and 'extract' the contents by right clicking on the folder. Then double click on the file 'Play video.html'. Note that the video has been compressed heavily so it can be downloaded, which means there is a slight loss in quality. If you have a problem with this, please e-mail David Read (d.read@soton.ac.uk). NOTE: YOU MUST DOWNLOAD AND EXTRACT THE ZIP FOLDER BEFORE CLICKING ON 'Play video.html' OTHERWISE IT WON'T WORK.