Search

A newly designed electron donor-acceptor conjugate consisting of an endohedral dimetallofullerene (La2@ Ih-C80) and phenoxazine (POZ) was successfully synthesized under Prato conditions. Our results document that the 1,3-dipolar cycloaddition took place across the [5,6] junction to afford exclusively the corresponding [5,6] cycloadduct. The structure of the conjugate was characterized by means of NMR spectroscopy, absorption spectroscopy, and electrochemical studies. Computational calculations suggest that the electron density of the highest occupied molecular orbital (HOMO) is distributed on the POZ moiety, whereas that of the lowest unoccupied molecular orbital (LUMO) is located at the endohedral La atoms, leading to efficient separation of the HOMO and LUMO in the conjugate. Time-resolved absorption spectroscopic investigations and spectroelectrochemical measurements corroborate the formation of the energetically low-lying (La2@ Ih-C80).−-(POZ).+ radical-ion-pair state by means of ultrafast through-space electron transfer. [ABSTRACT FROM AUTHOR]

Bis(sulfane)carbon(0) (BSC; Ph2S→C←SPh2 ( 1)) is successfully synthesized by deprotonation of the corresponding protonated salt 1⋅HTfO. The diprotonated salt 1⋅(HTfO)2 as the starting material can be also easily accessed by the deimination of iminosulfane(sulfane)carbon(0) (iSSC) ⋅HBF4. Density functional theory calculations revealed the peculiar electronic structure of 1, which has two lone pairs of electrons at the central carbon atom. The largest proton affinities (PA(1): 297.5 kcal mol−1; PA(2): 183.7 kcal mol−1) and the highest energy levels of the HOMOs (HOMO: −4.89 eV; HOMO−1: −5.02 eV) for 1 among the two-sulfur-stabilized carbones clearly indicate the strong donor ability of carbon center stabilized by two SII ligands. The donating ability of these lone pairs of electrons is demonstrated by the C-diaurated and C-proton-aurated complexes, which provide the first experimental evidence for two-sulfurstabilized carbones behaving as four-electron donors. Furthermore, the syntheses and application of AgI carbone complexes as carbone transfer agents are also reported. [ABSTRACT FROM AUTHOR]

Abstract: MIIFe2O4 (M=Mn, Co) nanoparticles with diameters less than 10nm were prepared by a fast and simple microwave-assisted method using ethylene glycol (EG) and ferric salts as starting reagents. The use of microwave field during preparation dramatically enhanced the crystallization rate. Therefore, well-crystallized MnFe2O4 and CoFe2O4 nanoparticles were prepared under microwave heating for 10min without calcining steps. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). In addition, both MnFe2O4 and CoFe2O4 nanoparticles exhibit a small hysteresis loop at room temperature. [Copyright &y& Elsevier]

Electronic effects on the central carbon atom of carbone, generated by the replacement of the SIV ligand of carbodisulfane (CDS) with other chalcogen ligands (Ph2E, E=S or Se), were investigated. The carbones Ph2E→C←SPh2(NMe) [E=S( 1) or Se( 2)] were synthesized from the corresponding salts, and their molecular structures and electronic properties were characterized. The carbone 2 is the first carbone containing selenium as the coordinated atom. DFT calculations revealed the electronic structures of 1 and 2, which have two lone pairs of electrons at the carbon center. The trend in HOMO energy levels, estimated by cyclic voltammetry measurements, for the carbones and CDS follows the order of 2> 1>CDS. Analysis of a doubly protonated dication and trication complex revealed that the central carbon atom of 2 behaves as a four-electron donor. [ABSTRACT FROM AUTHOR]

Two‐sulfur‐stabilized carbones: the presence of a “second” lone pair on a coordinated atom significantly enhances the electron‐donating ability of the central carbon in carbones. The strongest electron‐donating ability of bis(sulfane)carbon(0) (BSC) among the two‐sulfur‐stabilized carbones was demonstrated by the generation of diprotonated salt BSC⋅H2+. The C‐digold(I) complexes of two‐sulfur‐stabilized carbones provide the first experimental proof of their four‐electron‐donating ability. More information can be found in the Full Paper by T. Fujii et al. on page 8694. [ABSTRACT FROM AUTHOR]

Abstract: MnCO3 submicrocubes and highly oriented MnCO3 nanocrystal assemblies with an ellipsoidal morphology have been successfully prepared by an ultrasonic solution approach. The effect of surfactants of sodium dodecylsulfate (SDS) and aerosol OT (AOT) on the morphology of MnCO3 was investigated. Highly oriented ellipsoidal assemblies composed of ∼5nm MnCO3 nanocrystals with porous nanostructures were prepared in the presence of SDS. Both sonochemical irradiation and surfactant play an important role in the formation of these highly oriented assemblies. Nanoporous Mn2O3 was obtained by thermal treatment of MnCO3 at 600°C in air. The shape of MnCO3 was sustained after thermal transformation to form nanoporous Mn2O3. The products were characterized by X-ray powder diffraction, transmission electron microscopy, selected-area electron diffraction, field emission scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetric analysis. [Copyright &y& Elsevier]

Abstract: Manganese oxide (hausmannite) polyhedral nanocrystals were prepared by a microwave-assisted solution-based method using Mn(CH3COO)2 and (CH2)6N4 at 80°C. The as-prepared Mn3O4 nanocrystals were characterized by means of X-ray diffraction, field-emission transmission electron microscopy, field-emission scanning electron microscopy and Raman spectrum. Mn3O4 polyhedral nanocrystals prepared by microwave heating at 80°C for 60min were of cubic and rhombohedral shapes with the edge lengths in the range of 15–40nm. Mn3O4 nanocrystals grew following the Ostwald ripening mechanism with increasing reaction time. High-resolution transmission electron microscopy and selected area electron diffraction confirm that the as-obtained polyhedral nanocrystals were single-crystalline. The magnetic behavior of Mn3O4 nanocrystals was studied. Mn3O4 nanocrystals show an obvious ferromagnetic behavior at low temperatures. The magnetic behavior of Mn3O4 nanocrystals was sensitive to crystal size. Ferromagnetic onset temperatures (T c) of samples 1 and 3 are 40.6 and 41.1K, respectively, lower than that observed for bulk Mn3O4 (42K). [Copyright &y& Elsevier]