44 research outputs found

    An element through the looking glass: Exploring the Au-C, Au-H and Au-O energy landscape

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    Gold, the archetypal “noble metal”, used to be considered of little interest in catalysis. It is now clear that this was a misconception, and a multitude of gold-catalysed transformations has been reported. However, one consequence of the long-held view of gold as inert metal is that its organometallic chemistry contains many “unknowns”, and catalytic cycles devised to explain gold's reactivity draw largely on analogies with other transition metals. How realistic are such mechanistic assumptions? In the last few years a number of key compound classes have been discovered that can provide some answers. This Perspective attempts to summarise these developments, with particular emphasis on recently discovered gold(III) complexes with bonds to hydrogen, oxygen, alkenes and CO ligands

    A comparative analysis of sliding mode controllers for overhead cranes

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    Three different controllers for reducing the swing angle in overhead cranes are developed and compared in this paper. Numerical simulations tests have been developed for analysing the control performance. The introduced solutions combine different slide surfaces with fuzzy logic rules

    Group 11 complexes with the bidentate di(1H-indazol-1-yl)methane and di(2H-indazol-2-yl)methane) ligands

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    Twenty-four new copper, silver and gold complexes based on a bis(pyrazolyl)methane ligand L (in detail L = L1, di(1H-indazol-1-yl)methane; L = L2, di(2H-indazol-2-yl)methane) are prepared. The [Cu(L)(PR3)2]X species have been obtained from the reaction of [CuX(PR3)2] with L upon the displacement of X from the copper coordination sphere. 1 : 1 [CuX2(L)] complexes were obtained when L1 reacts with CuX2 whereas under the same conditions, L2 gave the ionic species [CuX(L)2]X. When L1 reacts with CuCl2, however, the dinuclear [CuCl2(L1)]2 complex is formed which, upon treatment with dimethylformamide (DMF), gave the mononuclear derivative [CuCl2(L1)(DMF)]. L1 and L2 often show a different reactivity toward silver salts. For example, in the reaction with AgNO3, the ionic compound [Ag(L1)2]NO3 is obtained when L1 is used as a starting reagent and the neutral 1 : 2 adduct [AgONO2(k-L2)(k2-L2)] containing a mono and a bidentate ligand is formed when L2 is employed as a ligand. L1 gave 2 : 1 adducts with AgCX3SO3 (X = H or F) and AgClO4, whereas 1 : 1 adducts are formed under the same conditions with L2. L1 and L2 give analogous dinuclear ([Ag(O2CCF3)(L)]2) and mononuclear ionic species ([Ag(L)2]BF4) when they react with Ag(O2CCF3) and AgBF4 species. Two analogous gold(III) complexes [AuCl2(L)][AuCl4] have also been obtained in the reaction of L with AuCl3 when the reaction was carried out in an excess of the ligands. All the air- and thermally stable complexes have been characterized by analytical and spectral (IR, conductivity, ESI-MS, 1H and 13C NMR solution data) methods

    EUCHEME, EUropean CHemists for Energy, Materials and Environment. Intensive Programme (IP) Lifelong Learning Programme Erasmus

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    The main objective of the course is to provide a comprehensive and balanced overview of the most important aspects of different subjects (energy and materials production, fine chemicals, environment) related to organometallic chemistry, catalysis, advanced materials, green and environmental chemistry, bridging the gap between the need of advanced training and the actual offer in this fields

    Coordination Chemistry of Scorpionate-type Ligands

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    Since their discovery in 1966, poly(pyrazolyl)borates (Bpx and Tpx) have been extensively employed as anionic donor ligands in a wide variety of metal complexes. This family of ligands is highly versatile as their steric and electronic properties can be easily modified by changing either the number of pyrazole rings or by substituents thereon or at the boron/carbon center. Trofimenko coined the term ‘‘Scorpionates’’ for poly(pyrazolyl)borates due to their interchange between bidentate and tridentate coordination modes, as the coordination behaviour of the [RR’B(pz)2] ligands closely resembles the hunting habits of a scorpion. In this context, therein we report an overview of recent results obtained with bis- and trispyrazolylborate ligands bearing Br, iPr and Tn substituents in the pyrazole rings (BpBr3, TpBr3, TpiPr,Br, TpTn) towards some CuI, CuII, ZnII, CdII and RuII acceptors, together with the spectroscopic and structural characterization of the relative organometallic complexes
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