1,721,089 research outputs found
Homoleptic, mononuclear transition metal complexes of 1,2-dioxolenes: Updating their electrochemical-to-structural (X-ray) properties
No full textThis review updates the electrochemical and structural aspects of homoleptic quinoidal (or pseudo-quinoidal) molecules coordinated to (single) transition metal ions. In fact, since 1,2-dioxolenes are redox-active molecules able to shuttle reversibly through the sequence quinone/hydroquinone/catechol, their metal complexes can display both the ligand-centred and the metal-centred electron transfers, which in some cases can overlap or trigger internal charge reorganizations. Such extended electron transfer ability makes it difficult in some cases to ascertain the oxidation states of both the ligands and the metal. Joint structural and electrochemical investigation can in most cases succeed in solving the dilemma, but in a wider horizon further experimental (for instance, magnetic measurements) or theoretical supports (enlightenment on the composition of frontier orbitals) would be desirable. © 2005 Elsevier B.V. All rights reserved
AN ELECTROCHEMICAL INVESTIGATION ON MONONUCLEAR AND DINUCLEAR COPPER(I) AMINOCARBONYL COMPLEXES
No full textThe Redox Active [2Fe-2S] Clusters: Key-Components of a Plethora of Enzymatic Reactions—Part I: Archaea
Full text linkThe earliest forms of life (i.e., Archaea, Bacteria, and Eukarya) appeared on our planet about ten billion years after its formation. Although Archaea do not seem to possess the multiprotein machinery constituted by the NIF (Nitrogen Fixation), ISC (Iron Sulfur Cluster), SUF (sulfur mobilization) enzymes, typical of Bacteria and Eukarya, some of them are able to encode Fe-S proteins. Here we discussed the multiple enzymatic reactions triggered by the up-to-date structurally characterized members of the archaeal family that require the crucial presence of structurally characterized [2Fe-2S] assemblies, focusing on their biological functions and, when available, on their electrochemical behavior
REORIENTATION OF THE ALKYNE MOIETY IN FE3(CO)9(RC2R) CLUSTERS INDUCED BY A 2-ELECTRON ELECTROCHEMICAL REDUCTION
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The Redox Behaviour of Ferrocene Derivatives. VIII. 1,1'-bis(diphenyl-phosphino)ferrocenes
No full textA study has been made of the possibility of increasing the stability of the 1,1′-bis(diphenylphosphino)ferrocenium monocation by introduction of appropriate substituents into the cyclopentadienyl ligands. The electrochemical behaviour of a series of 1,1′-bis(diphenylphosphino)ferrocenes bearing substituents with a range of electronic properties has been examined. The results reveal that, the higher the electron-donating ability of the substituents, the longer is the lifetime of the corresponding 1,1′-bis(diphenylphosphino)ferrocenium monocation. However, no stable ferrocenium cation has been obtained; mass spectrometry shows that mixtures of mono- and di-bis(diphenylphosphine)oxides are ultimately formed as products resulting from decomposition of the initially electrogenerated 1,1′-bis(diphenylphosphino)ferrocenium species
Bimetallic effects on the redox activity of transition-metal carbonyl clusters
No full textMetal cluster chemistry is at the cutting edge between molecular and solid-state chemistry and has therefore had a great impact on the researchers working on organic, coordination, and solid-state chemistry, catalysis, physics, and materials science. The development of new sophisticated synthetic techniques has led to enormous progress in the synthesis of this diverse class of compounds. The number of clusters is growing rapidly, since the possible variations in the metal and ligand sphere are numerous. Modern bonding theories, such as the isolobal principle, have allowed a better understanding of the structures and properties of metal clusters, and thus paved the way for the usage of these versatile materials. Catalysis and nanomaterials are just two of the very promising application-oriented fields.
Seventy six contributions, written by world experts in this research field, provide extensive coverage of different aspects of cluster chemistry, ranging from synthesis, structure determination, and dynamics to applications. Up-to-date information, including an impressive collection of structural data and illustrations, extensive coverage of the most important publications of the last decade, and many more features make this three-volume set a complete single-source guide for all researchers working in the area of cluster chemistry
Regiospecific Allyl-alkyne Coupling On An Organotriruthenium Carbonyl Cluster - Crystal-structure of Ru3(co)8(mu-eta-1-eta-1-eta-4-phc=c(ph)c(me)=cch2nme2)
No full textThe reaction of Ru3(H)(CO)9(MeCCHCNMe2), having an allyl moiety σ-π bonded to the triruthenium frame, with diphenylacetylene yields Ru3(CO)8-(PhC2PhMeC2CH2NMe2), containing the 1-(dimethylamino)-3-methyl-4,5-diphenylpentadiene ligand coordinated to an intact triruthenium triangle. The organic ligand acts as an overall 8e donor to the metal triangle via σ-π metal-carbon bonds and a σ metal-nitrogen bond. © 1990, American Chemical Society. All rights reserved
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