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We demonstrate that sequential disproportionation reactions can enable selective aggregation of two- or four electron–holes at a hypervalent iodine center. Disproportionation of an anodically generated iodanyl radical affords an iodosylbenzene derivative. Subsequent iodosylbenzene disproportionation can be triggered to provide access to an iodoxybenzene. These results demonstrate multielectron oxidation at the one-electron potential by selective and sequential disproportionation chemistry. [ABSTRACT FROM AUTHOR]

Here, we report a synthesis of Cu nanocubes by photoreduction of CuSO4. Because synthetic saponite (one of the layered clay minerals) was used as the adsorbent, the nanocubes contained no capping agents or protectants, and the disproportionation reaction of Cu2O with H2SO4 was found to be the key for morphological control. [ABSTRACT FROM AUTHOR]

Reduction of the group 4 transition metal precursors [(PN)2MCl2] (M = Zr (1), and Hf (2)); PN− = (N-(2-(diisopropylphosphino)-4-methylphenyl)-2,4,6-trimethylanilide), both readily prepared by transmetallation of 2 LiPN with [MCl4(THF)2], with a slight excess of KC8, resulted in the isolation of the trivalent complexes [(PN)2MCl] (M = Zr (3), and Hf (4)). Complexes 1–4 were all identified by solid-state X-ray diffraction analysis, whereas in the case of 3 and 4 low temperature X-band EPR spectroscopy allowed for the identification of these metal-centered d1 radicals. A comparison with the isostructural and isoelectronic but more stable [(PN)2TiCl] is also presented. [ABSTRACT FROM AUTHOR]

Oxo-vanadium complexes are found to catalyze the redox disproportionation of benzylic and allylic alcohols, which results in co-production of carbonyl products and reductively coupled hydrocarbon dimers. Preliminary experimental and computational findings suggest the intervention of reduced V-alkoxide species, which undergo facile C–O bond homolysis to produce carbon free radicals, precursors to the hydrocarbon dimers. [ABSTRACT FROM AUTHOR]

We report the first example of CuI-catalysed coupling of alkylboron reagents with aryl and heteroaryl iodides that affords products in good to excellent yields. Preliminary mechanistic studies with alkylborates indicate that the anionic (alkoxy)(alkyl)borates, generated from alkyllithium and alkoxyboron reagents, undergo disproportionation to anionic dialkylborates and that both anionic alkylborates are active for transmetalation to a CuI-catalyst. Results from a radical clock experiment and the Hammett plot imply that the reaction likely proceeds via a non-radical pathway. [ABSTRACT FROM AUTHOR]

The reductive disproportionation of nitric oxide (1 atm) is mediated by the bulky UIII aryloxide [UIII(OArAd,Ad,Me)3] (Ad,Ad,MeArO = O-C6H2-2,6-Ad-4-Me) (1) to form the UV terminal oxo species [(Ad,Ad,MeArO)3UV(O)] (2) and N2O, as confirmed by single crystal X-ray diffraction and GC-MS measurements. The reaction is quantitative in the solid state. Mechanistic and theoretical studies of the reaction suggest that the N–N bond is formed by the coupling of an η1-O bound nitric oxide ligand with gaseous NO to give an η1-(N2O2)1− intermediate prior to the spontaneous extrusion of N2O to yield the UV terminal oxo species 2. [ABSTRACT FROM AUTHOR]

Interaction between adsorbed t-butyl peroxybenzoate and photoexcited graphene rendered trapped phenyl and t-butoxy radicals. Post-irradiation thermal desorption showed benzene, t-butanol, and isobutylene oxide as the end products. The required hydrogen atoms were obtained via the radical disproportionation. Graphene enabled radical species to be captured and their on-surface chemistry to be revealed. [ABSTRACT FROM AUTHOR]

A quasi in situ X-ray absorption study demonstrated that the disproportionation of hydrogen peroxide (H2O2) promoted by ceria nanorods was associated with a reversible Ce3+/Ce4+ reaction and structural transformations in ceria. The direction of this reversible reaction was postulated to depend on the H2O2 concentration and the fraction of Ce3+ species in ceria nanorods. [ABSTRACT FROM AUTHOR]

There is a controversial debate about the mechanism of the Cu0-catalyzed radical polymerization. Herein, a comparative analysis of a series of reactions catalyzed by different valent copper shows that the induction period and the subsequent autoaccelerated polymerization of a Cu0/Me6TREN-catalyzed system originate from the accumulation of soluble copper species, and CuI is still a powerful activator under its disproportionation favored conditions. [ABSTRACT FROM AUTHOR]

A novel charge-disproportionation state with δ = 0.75 was observed in an electron-donor (D)/-acceptor (A) Dδ+2A2δ− layered framework by chemically tuning the electron-donating affinity of D at the boundary between D0.5+2A− and D+2A2− phases, which was pressure-sensitive due to the formation of the D+2A2− oxidation state. [ABSTRACT FROM AUTHOR]

A Cr(iv)η2–peroxo complex crystallizes from 33% aqueous H2O2. The complex is a likely intermediate in catalytic disproportionation of H2O2 proposed to occur through a single metal site mechanism in solution – and solid state. [ABSTRACT FROM AUTHOR]

High-resolution FT-IR spectroscopy combined with quantum chemical calculations was used to study the chemistry of OCSdisproportionation over the reduced surface of isotopically labelled, nanocrystalline TiO2. Analysis of the isotopic composition of the product gases has revealed that the reaction involves solely OCS molecules from the gas-phase. Using quantum chemical calculations we propose a plausible mechanistic scenario, in which two reduced Ti3+ centres mediate the reaction of the adsorbed OCS molecules. [ABSTRACT FROM AUTHOR]

To design new metal string complexes, several naphthyridyl group modulated oligo-α-pyridylamido ligands have been synthesized in the past five years. Because these ligands are less anionic than pyridylamido ligands, the resulting metal string complexes tend to form reduced mixed-valence [Ni2(napy)4]3+ dinuclear units which contain a delocalized unpaired electron and thus significantly enhance the conductance of metal string complexes. Furthermore, the asymmetric naphthyridyl group modulated oligo-α-pyridylamido ligands can stabilize the central heteronuclear or charge disproportionational metal frameworks, providing a plausible strategy to build inorganic molecular rectifiers. [ABSTRACT FROM AUTHOR]

Electron-transfer disproportionation of a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH...) occurred in the presence of Sc3+ acting as a strong Lewis acid in deaerated acetonitrile. In contrast, in the case of weaker Lewis acids than Sc3+, such as Mg2+ and Li+, external protons from acetic acid were required for the disproportionation of DPPH... to occur. [ABSTRACT FROM AUTHOR]

A stimuli-responsive material with AND logic function was realized by modulating sensitive Cu–Cu interactions, which is quite different from traditional photoinduced electron transfer (PET) strategies. The obtained material not only gets rid of fluid media, but also displays nondestructive, high intensity optical signals and environmentally friendly performances. [ABSTRACT FROM AUTHOR]

This work reports the first example of the transformation of conglomerate (R)- and (S)-crystals into racemic crystals via sublimation. Crystallographic analysis of racemic isopropyl 3,3,3-trifluoro-2-hydroxypropanoate did not reveal the highly expected heterochiral dimer indicating that this compound is capable of forming exclusively homochiral oligomers via infinite multi-centred H-bonding networks. [ABSTRACT FROM AUTHOR]

The reaction of benzoic acid with the uranyl(V) complex [(UO2Py5)(KI2Py2)] in pyridine leads to immediate disproportionation with formation of a hexanuclear U(IV) benzoate cluster, a bis-benzoate complex of uranyl(VI) and water. [ABSTRACT FROM AUTHOR]

The mixed-sandwich U(III) complexes [U(η-C8H6{SiiPr3-1,4}2)(η-CpR)(THF)] (R = Me5, Me4H) react with CO2 to give free CO and the U(IV) carbonate products [U(η-C8H6{SiiPr3-1,4}2)(η-CpR)]2(μ-η1:η2-CO3)]; the latter has been structurally characterised for R = Me4H; a 25% molar excess of the U(III) reductant gives a mixture of the carbonate and squarate [U(η-C8H6{SiiPr3-1,4}2)(η-C5Me4H)]2(μ-η2:η2-C4O4) products—the first synthesis of an oxocarbon from a CO2 carbon source. [ABSTRACT FROM AUTHOR]