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Bi2FeMnO6 ceramics were prepared under atmospheric pressure and a high pressure of 1–6 GPa. The effects of different high‐pressure syntheses on the microstructures were analyzed by X‐ray diffraction and Rietveld refinement, scanning electron microscopy–energy‐dispersive spectroscopy, X‐ray photoelectron spectrometer, and Raman spectroscopy test. The temperature dependence of magnetization was systematically investigated for all samples. There was a transition from rhombohedral R3c structure to orthorhombic phase Pnam with increasing synthetic pressure. The samples synthesized under atmospheric pressure are rhombohedral R3c with antiferromagnetic (AFM) magnetic temperature (M–T curves). The samples synthesized under a high pressure of 5–6 GPa are orthorhombic phase Pnam with the magnetization reversal effect, whereas the lower high‐pressure (1–3 GPa) synthesized samples might be in the transitional area between them. This structural transformation is accompanied by the transformation from normal AFM M–T curves to a typical magnetization reversal effect. The relationship between the lattice distortion and the internal magnetic competition mechanism of the material was discussed. The existence of magnetization reversal in these systems may ascribe to the competition between the single‐ion magnetic anisotropy and the Dzyaloshinsky–Moriya interaction. [ABSTRACT FROM AUTHOR]

The Bi5Ti3(Fe1−xCox)O15 (x = 0, 0.4, 0.5, 0.6, 0.7) ceramics synthesized by solid state reaction are investigated. The microstructures are Aurivillius phase with perovskite layered structure, which were analyzed by X-ray diffraction and Raman spectroscopy test. The temperature-dependent magnetization was systematically investigated for all samples with different Co doping ratios. The magnetization reversal effects were found in both ZFC and FC curves with one or two compensation temperature. And the compensate temperatures change with different x. The temperature-induced magnetization reversal may attribute to the competition between the super-exchange interaction of Fe3+-O-Fe3+ and Co3+-O-Co3+, the DM interaction of Fe3+-O-Co3+ chains, and the magneto-crystalline anisotropy. This competition can be affected by the contents of Fe ions to Co ions. The study of multiferroic material Bi5Ti3(Fe1−xCox)O15 ceramics with magnetization reversal effects has important significance in the Information Security Engineering, for the switch effect with different magnetizations and temperatures. [ABSTRACT FROM AUTHOR]

3-alkylated anisole compounds of pentaammineosmium(II) were treated with methyl vinyl ketone and triflic acid to form 4H-anisolium Michael adducts, which deprotonate regioselectively at the benzylic position next to C3, after which they undergo an aldol cyclization. The dienonium product reduction can be directed in 1,4 way to provide a trans decalin, or in a 1,2 way to provide methoxydiene.

Complexation of an arene by an electron-deficient transition metal center has been much researched over the past 30 years. Anisoles were complexed by pentaammineosmium(II) and the result 5,6-eta2-anisole compounds were treated with activated olefins or acetals, forming 4H-anisolium compounds. They were able to undergo inter or intramolecular nucleophilic addition reactions, and 2-methoxy-1,3-cyclohexadiene complexes were formed. These can be readily converted into functionalized cyclohexenones, cyclohexadienes, and cyclohexenes.

A study was conducted on the reaction of the complex of [Os(NH3)5(eta2-anisole)]2+ with acetals or Michael acceptors to produce 4-methoxystyrene complexes that are exclusively coordinated at the arene (eta2). These styrene complexes are active dienes and are involved in Diels-Adler reactions with electron-deficient olefins to form tetrahydronaphthalene complexes. The cycloadducts are produced as single diastereomers and are essential as precursors to functionalized tetralins and decalins.

An experiment evaluated the basic transmutations of eta2-coordinated furan complexes of pentaammineosmium(II). Coordination of the electron-rich pentaammineosmium(II) moiety to a furan significantly changes the structural and chemical character of the ligand, with the generated complexed ligands easily experiencing different electrophilic addition reactions that feature two reactive species. These species are the apparently interchangeable open-chain eta2-vinyl cation species and eta2-3H-furanium species.

The coordination of the pentaammineosmium(II) metal center to different kinds of anisoles has been found to radically increase the nucleophilicity of the arene. Reactions occur with a large variety of carbon electrophiles in the presence of acidic acetonitrile at -40 degrees C to produce characterizable 4H-anisolium intermediates. Upon deprotonation and decomplexation, the 4-substituted anisole is returned in overall yields usually greater than 80 %.

Reaction of anionic cyclohexadienyl complexes with primary halides produces 1, 3-cyclohexadienes having a 1,5,6 -substitution pattern and proceeds through exonucleophilic addition to a position ortho to the arene and an electrophilic addition to the metal center. Allyl, benzyl and propargyl halides produce trans-5,6-substituted products and alkyl halide produces acylcyclohexadienes. Acyclcyclohexadienes on deprotonation/methylation produce products having three C-substituents added across an arene double bond.

The methodology for the vicinal difunctionalization of furan due to eta(super 2) complexation of furan with a transition metal is extended for heterocyclic synthesis. An eta(super 2)-furan complex containing osmium reacts with different electrophiles and the reactivities are compared. ORTEP diagrams reveal the distortion in the furan ligand which resembles a vinyl ether due to metal binding. Furan loses its aromaticity due to complexation.