The use of conductivity measurements in organic solvents for the characterisation of coordination compounds

For present purposes, a protein-bound metal site consists of one or more metal ions and all protein side chain and exogenous bridging and terminal ligands that define the first coordination sphere of each metal ion. Such sites can be classified into five basic types with the indicated functions: (1) structural -- configuration (in part) of protein tertiary and/or quaternary structure; (2) storage -- uptake, binding, and release of metals in soluble form: (3) electron transfer -- uptake, release, and storage of electrons; (4) dioxygen binding -- metal-O{sub 2} coordination and decoordination; and (5) catalytic -- substrate binding, activation, and turnover. The authors present here a classification and structure/function analysis of native metal sites based on these functions, where 5 is an extensive class subdivided by the type of reaction catalyzed. Within this purview, coverage of the various site types is extensive, but not exhaustive. The purpose of this exposition is to present examples of all types of sites and to relate, insofar as is currently feasible, the structure and function of selected types. The authors largely confine their considerations to the sites themselves, with due recognition that these site features are coupled to protein structure at all levels. In themore » next section, the coordination chemistry of metalloprotein sites and the unique properties of a protein as a ligand are briefly summarized. Structure/function relationships are systematically explored and tabulations of structurally defined sites presented. Finally, future directions in bioinorganic research in the context of metal site chemistry are considered. 620 refs.« less

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Structural and Functional Aspects of Metal Sites in Biology

Publisher Summary There have been many reviews and books on electron spin resonance (ESR) and several on transition metal ions. Many of these publications have been written by physicists or theoreticians and are very comprehensive. This review is aimed at inorganic chemists, who have had no experience relating to electron spin resonance and who are becoming more and more likely either to use the technique or to need to appreciate the significance of the information available from the technique. The first part of the review gives an elementary account of the relevant theory. There are many good books for further reading for the inorganic chemist, who wishes to go deeper into the subject. The second part of the review is a comprehensive survey of the results of ESR studies on compounds of transition elements. Inevitably, there has had to be some selection of material, and the criteria for inclusion or rejection has been based upon the likely interest of an inorganic chemist might have in the species. This is particularly in the areas, where there is a lot of related work, e.g., the Mn2+ host-lattice data. In the case of copper dg complexes, there has been much duplication of work and papers devoted to the spectra of complexes where a minor substitutive change has been made to a bulky organic ligand.

Electron Spin Resonance of Transition Metal Complexes

Die Reaktion von Schwefelkohlenstoff mit Natrium oder Kalium fuhrt zur Bildung aquimolarer Mengen von 1.3-Dithiol-2-thion-4.5-dithiolat (1) und Trithiocarbonat. Durch Zugabe von ZnCl2 und NEt4Br last sich (1) stabilisieren. Der entstehende Zink-Komplex ermoglicht die Herstellung von 4.5-Bis(benzoylthio)-1.3-dithiol-2-thion (10), woraus durch Umsetzung mit Basen (1) in quantitativer Ausbeute wieder entsteht. Die Alkylierung von (1) fuhrt zu 4.5-Bis(alkylthio)-1.3-dithiol-2-thionen. (1) is ein neuer, schwefelreicher 1.2-Dithiolat-Ligand. Die Kristallstruktur des Bis-Chelates von (1) mit Ni(II) als (n-Bu4N)2-Salz bestatigt die fur (1) angenommene Struktur. The reaction of carbon disulfide with sodium or potassium in dimethyl formamide yields 1,3-dithiole-2-thione-4,5-dithiolate (1) and trithiocarbonate in equimolar amounts. (1) was stabilized by addition of ZnCl2 and NEt4Br. The resulting zinc complex enables the isolation of 4,5-bis(benzoylthio)-1,3-dithiole-2-thione (10). (1) can be recovered from...

1.3-dithiol-2-thion-4.5-dithiolat aus schwefelkohlenstoff und alkalimetall

This article reviews recent work in the area of non-innocent behaviour in polynuclear metal complexes Non-innocence, which occurs when metal-based and ligand-based redox orbitals are similar in energy, has been known since the first dithiolene complexes of the Ni triad Our recent work in this field is with complexes of two distinct types: polynuclear complexes of Ru(II) with dioxolene-type bridging ligands; and dinuclear complexes based on tris(pyrazolyl)borato-Mo(V) or -Mo(I) units linked by bis-phenolate or bis-pyridyl bridging ligands Detailed redox and UV/Vis/NIR spectroelectrochemical studies on these complexes have been carried out An important point which emerges is that non-innocent behaviour in dinuclear complexes is an essential prerequisite for strong metal–metal electronic coupling across extended bridging ligands Many of the complexes studied show intense charge-transfer transitions in the near-IR region of the
spectrum, and the use of these in prototypical optical devices is briefly discussed

Non-innocent behaviour in mononuclear and polynuclear complexes: consequences for redox and electronic spectroscopic properties

Electron Paramagnetic Resonance Studies of the Electronic Structures of Bis(maleonitriledithiolato)copper(II), -nickel(III), -cobalt(II), and -rhodium(II) Complexes

N. Edelstein

Papers

Electron Paramagnetic Resonance Studies of the Electronic Structures of Bis(maleonitriledithiolato)copper(II), -nickel(III), -cobalt(II), and -rhodium(II) Complexes

The Preparation and Characterization of Four-Coordinate Complexes Related by Electron-Transfer Reactions

Synthetic and Electron Spin Resonance Studies of Six-Coordinate Complexes Related by Electron-Transfer Reactions

E.s.r. Studies of Four-Coördinate Complexes of Nickel, Palladium and Platinum Related by Electron Transfer Reactions

Further Examples of Complexes Related by Electron-Transfer Reactions: Complexes Derived from Bis (trifluoromethyl)-1,2-dithietene