162 research outputs found
Ethiopiaâs Grand Renaissance Dam: A Solution for Cooperation in the Nile Watershed or a Source of Conflict?
Group 11 tris(pyrazolyl)methane complexes: structural features and catalytic applications
Tris(pyrazolyl)methane ligands (Tpmx) have been for years a step behind their highly popular boron-anionic analogues, the tris(pyrazolyl)borate ligands (Tpx). However, in the last decade the development of new members of this family of ligands has boosted a number of contributions albeit their use in coordination chemistry. This fact has also triggered the application of metal-Tpmx complexes as catalysts for a range of organic transformations, particularly with group 11 metals. The main structural features of complexes containing the TpmxM (M = Cu, Ag, Au) unit and their success as catalysts in a variety of reactions under homogeneous or heterogeneous conditions are presented.We thank MINECO for support with Grant CTQ2017-82893-C2-1-
Novel Scorpionate and Pyrazole Dioxovanadium Complexes, Catalysts for Carboxylation and Peroxidative Oxidation of Alkanes
The dioxovanadium(V) complexes [VO2(3,5-Me(2)Hpz)(3)][BF4] (1) (pz = pyrazolyl), [VO2{SO3C(pz)(3)}] (2), [VO2{HB(3,5-Me(2)pz)(3)}] (3) and [VO2{HC(pz)(3)}][BF4] (4), bearing pyrazole or scorpionate ligands, were obtained by reaction of triethyl vanadate [VO(OEt)(3)] with hydrotris(3,5-dimethyl-1-pyrazolyl)methane [HC(3,5-Me(2)pz)(3)] or 3,5-dimethylpyrazole (3,5-Me(2)Hpz; 1), lithium tris(1-pyrazolyl)methanesulfonate {Li[SO3C(pz)(3)], 2}, potassium hydrotris(3,5-dimethyl-1-pyrazolyl)borate {K[HB(3,5-Me(2)pz)(3)], 3} and hydrotris(1-pyrazolyl)methane [HC(pz)(3), 4], respectively. Treatment of [VO(OEt)(3)] with potassium hydrotris(1-pyrazolyl)borate {K[HB(pz)(3)]} led to the mixed eta(3)-tris(pyrazolyl)borate and eta(2)-bis(pyrazolyl)borate oxovanadium(IV) complex [VO{HB(pz)(3)}{H2B(pz)(2)}, 5]. The compounds were characterized by elemental analyses, IR, NMR and EPR spectroscopy, FAB and ESI mass spectrometry, cyclic voltammetry and, for 5, also by single crystal X-ray diffraction analysis. All complexes exhibit catalytic activity in the single-pot carboxylation [in trifluoroacetic acid/potassium peroxodisulfate (CF3COOH/K2S2O8)] of gaseous alkanes (methane and ethane) to carboxylic acids (yields up to 40%. TONs up to 157) and in the peroxidative oxidation [in water/acetonitrile (H2O/NCMe)] of liquid alkanes (cyclohexane and cyclopentane) to the corresponding alcohols and ketones (yields up to 24%, TONs up to 117), under mild conditions
Synthesis and Characterization of Ferrocene-Chelating Heteroscorpionate Complexes of Nickel(II) and Zinc(II)
The sustainability of multicultural education projects offered by NGOs, and their categorization in terms of the level of sustainability
Synopsis This work focuses on multicultural education projects that are offered by civic sector organizations, and assesses thein sustainability. The theoretical part summarizes the theoretical knowledge concerning the development and the definitiv of multicultural education in the Czech Republic. It also attempts to clarify what the project of multicultural education entails, and tries to analyze the theoretical koncept of project sustainability. The practical part of the work includes empirici research on the sustainability of multicultural education project in the Czech Republic. It describes the ganges that occur during the sustainability phase of the project
The sustainability of multicultural education projects offered by NGOs, and their categorization in terms of the level of sustainability
Synopsis This work focuses on multicultural education projects that are offered by civic sector organizations, and assesses thein sustainability. The theoretical part summarizes the theoretical knowledge concerning the development and the definitiv of multicultural education in the Czech Republic. It also attempts to clarify what the project of multicultural education entails, and tries to analyze the theoretical koncept of project sustainability. The practical part of the work includes empirici research on the sustainability of multicultural education project in the Czech Republic. It describes the ganges that occur during the sustainability phase of the project
Olefin Polymerisation Catalysts Derived from Titanium and Vanadium Tris(pyrazolyl)methane Complexes
This Thesis describes the synthesis and characterisation of titanium and vanadium complexes supported by tris(pyrazolyl)methane and tris(pyrazolyl)methide type ligands. The ethylene polymerisation capability of a selection of these complexes is investigated. Chapter 1 introduces homogenous Ziegler-Natta catalysis, including the role of titanium and vanadium imido complexes. The tris(pyrazolyl)methane ligand is also introduced, along with examples of its use in Group 4 and Group 5 complexes. Chapter 2 describes the synthesis and characterisation of new titanium and vanadium imido synthons. Chapter 3ĂâĂ· describes the synthesis of vanadium imido complexes supported by fac-N3 ligands. The ethylene polymerisation capability of a selection of these complexes tested both at room temperature and under industrially relevant conditions will be described Chapter 4 describes the synthesis of new zwitterionic titanium imido complexes, supported by the tris(pyrazolyl)methide ligand. The synthesis of new titanium. imido tris(pyrazolyl)hydroborate complexes will also be described. The ethylene polymerisation capability of the new complexes will be described. Chapter 5 describes the synthesis of new titanium amidinate complexes, along with the ethylene polymerisation studies for selected complexes. A series of new tin-, magnesium- and zinc-tris(pyrazolyl)methide complexes will also be described. Chapter 6 presents full experimental procedures for all of the syntheses and polymerisation studies outlined in Chapters 2 to 5. Chapter 7 contains characterising data for all of the new compounds reported. Appendices A - X contain tables of selected crystallographic data for all new crystallographically characterised complexes described in this Thesis.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Introducing Child Care Social Work: contemporary Policy and Practice
This book was co-authored by students undertaking a post qualifying award in children and families social work
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