Tetra­aqua­bis{μ2-2,7-bis­[(2,6-diisopropyl­phen­yl)imino­meth­yl]naphthalene-1,8-diolato}di-μ3-hydroxido-di-μ2-hydroxido-bis­(trimethyl­phosphine oxide)tetra­nickel(II)–trimethyl­phosphine oxide–diethyl ether–water (1/2/2/2)

The title complex, [Ni4(C36H40N2O2)2(OH)4(C3H9OP)2(H2O)4]·2C4H10O·2C3H9OP·2H2O, is centrosymmetric with a central core that can be described as a defect double cubane. The four metal ions in the cluster are held together by four bridging hydroxide groups. Each NiII atom adopts a distorted octa­hedral geometry

Synthesis and Electronic Structure Determination of Uranium(VI) Ligand Radical Complexes

   Pentagonal bipyramidal uranyl complexes of salen ligands, N,N’-bis(3-tert-butyl-(5R)-salicylidene)-1,2-phenylenediamine, in which R = tBu (1a), OMe (1b), and NMe2 (1c), were prepared and the electronic structure of the one-electron oxidized species [1a-c]+ were investigated in solution. The solid-state structures of 1a and 1b were solved by X-ray crystallography, and in the case of 1b an asymmetric UO22+ unit was found due to an intermolecular hydrogen bonding interaction. Electrochemical investigation of 1a-c by cyclic voltammetry showed that each complex exhibited at least one quasi-reversible redox process assigned to the oxidation of the phenolate moieties to phenoxyl radicals. The trend in redox potentials matches the electron-donating ability of the para-phenolate substituents. The electron paramagnetic resonance spectra of cations [1a-c]+ exhibited gav values of 1.997, 1.999, and 1.995, respectively, reflecting the ligand radical character of the oxidized forms, and in addition, spin-orbit coupling to the uranium centre. Chemical oxidation as monitored by ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy afforded the one-electron oxidized species. Weak low energy intra-ligand charge transfer (CT) transitions were observed for [1a-c]+ indicating localization of the ligand radical to form a phenolate / phenoxyl radical species. Further analysis using density functional theory (DFT) calculations predicted a localized phenoxyl radical for [1a-c]+ with a small but significant contribution of the phenylenediamine unit to the spin density. Time-dependent DFT (TD-DFT) calculations provided further insight into the nature of the low energy transitions, predicting both phenolate to phenoxyl intervalence charge transfer (IVCT) and phenylenediamine to phenoxyl CT character. Overall, [1a-c]+ are determined to be relatively localized ligand radical complexes, in which localization is enhanced as the electron donating ability of the para-phenolate substituents is increased (NMe2 > OMe > tBu)

Methyl Complexes of the Transition Metals

Organometallic chemistry can be considered as a wide area of knowledge that combines concepts of classic organic chemistry, that is, based essentially on carbon, with molecular inorganic chemistry, especially with coordination compounds. Transition-metal methyl complexes probably represent the simplest and most fundamental way to view how these two major areas of chemistry combine and merge into novel species with intriguing features in terms of reactivity, structure, and bonding. Citing more than 500 bibliographic references, this review aims to offer a concise view of recent advances in the field of transition-metal complexes containing M-CH fragments. Taking into account the impressive amount of data that are continuously provided by organometallic chemists in this area, this review is mainly focused on results of the last five years. After a panoramic overview on M-CH compounds of Groups 3 to 11, which includes the most recent landmark findings in this area, two further sections are dedicated to methyl-bridged complexes and reactivity.Ministerio de Ciencia e Innovación Projects CTQ2010–15833, CTQ2013-45011 - P and Consolider - Ingenio 2010 CSD2007 - 00006Junta de Andalucía FQM - 119, Projects P09 - FQM - 5117 and FQM - 2126EU 7th Framework Program, Marie Skłodowska - Curie actions C OFUND – Agreement nº 26722

Dissertatio Physiologico-Anatomica De Lacte

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Phosph(on/in)ate-Bridged Vanadium(IV) Dimers: Synthesis and Characterization

A series of dinuclear organophosphorus-bridged complexes of the general formula {(LVO­(μ-O₂PRR′)}₂ [L = η⁵-cyclopentadienyltris­(diethylphosphito-κ¹<i>P</i>) cobaltate­(III)] has been synthesized as a structural model for the industrially used vanadium phosphate oxidation catalysts. These dimeric species contain two vanadium centers in a VO₆ environment bridged by O–P–O units. These complexes have been characterized via spectral and magnetic analyses. Structural parameters have been analyzed through X-ray diffraction. The dimers generally exist in either a <i>cis/cis</i>-anti or retracted chair conformation in the solid state. The syntheses, structural, spectral, and magnetic data are presented and discussed here

Phosph(on/in)ate-Bridged Vanadium(IV) Dimers: Synthesis and Characterization

A series of dinuclear organophosphorus-bridged complexes of the general formula {(LVO­(μ-O₂PRR′)}₂ [L = η⁵-cyclopentadienyltris­(diethylphosphito-κ¹<i>P</i>) cobaltate­(III)] has been synthesized as a structural model for the industrially used vanadium phosphate oxidation catalysts. These dimeric species contain two vanadium centers in a VO₆ environment bridged by O–P–O units. These complexes have been characterized via spectral and magnetic analyses. Structural parameters have been analyzed through X-ray diffraction. The dimers generally exist in either a <i>cis/cis</i>-anti or retracted chair conformation in the solid state. The syntheses, structural, spectral, and magnetic data are presented and discussed here