[en] The lability of B=B, B-P, and B-halide bonds is combined in the syntheses of the first diiododiborenes. In a series of reactivity tests, these diiododiborenes undergo cleavage of all six of their central bonds in different ways, leading to products of B=B hydrogenation and dihalogenation as well as halide exchange. (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

[en] To improve the bioimaging signal-to-noise ratio (SNR), long-term imaging capability, and decrease the potential biotoxicity, an in vivo cross-linking strategy was developed by using sub-10 nm, glutathione-modified, lanthanide nanoprobes. After administration, the nanoprobes cross-link in response to reactive oxygen species (ROS) at the inflamed area and enable the quick imaging of ROS in the second near-infrared (NIR-II) window. These nanoprobes could be rapidly excreted due to their ultra-small size. This strategy may also be applied to other ultra-small contrast agents for the precise bioimaging by in situ lesion cross-linking. (copyright 2019 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] Upconversion core/shell nanocrystals with different mean sizes ranging from 15 to 45 nm were prepared via a modified synthesis procedure based on anhydrous rare-earth acetates. All particles consist of a core of NaYF₄:Yb,Er, doped with 18 % Yb³⁺ and 2 % Er³⁺, and an inert shell of NaYF₄, with the shell thickness being equal to the radius of the core particle. Absolute measurements of the photoluminescence quantum yield at a series of different excitation power densities show that the quantum yield of 45 nm core/shell particles is already very close to the quantum yield of microcrystalline upconversion phosphor powder. Smaller core/shell particles prepared by the same method show only a moderate decrease in quantum yield. The quantum yield of 15 nm core/shell particles, for instance, is reduced by a factor of three compared to the bulk upconversion phosphor at high power densities (100 W cm^-2) and by approximately a factor of 10 at low power densities (1 W cm^-2). (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] When doped with oxygen, the layered Y_2O_2Bi phase becomes a superconductor. This finding raises questions about the sites for doped oxygen, the mechanism of superconductivity, and practical guidelines for discovering new superconductors. We probed these questions in terms of first-principles calculations for undoped and O-doped Y_2O_2Bi. The preferred sites for doped O atoms are the centers of Bi_4 squares in the Bi square net. Several Bi 6p x/y bands of Y_2O_2Bi are raised in energy by oxygen doping because the 2p x/y orbitals of the doped oxygen make antibonding possible with the 6p x/y orbitals of surrounding Bi atoms. Consequently, the condition necessary for the ''flat/steep'' band model for superconductivity is satisfied in O-doped Y_2O_2Bi. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] The right environment: The remarkable properties of a recently reported holmium(III)-based single-ion magnet have been ascribed to the hyperfine interactions with the half-integer nuclear spin in combination with the pentagonal-bipyramidal coordination environment. These results provide insight into the complicated magnetic properties of nanosized magnetic materials. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] The blood-red plutonocene complex Pu(1,3-COT'')(1,4-COT'') (4; COT''=η⁸-bis(trimethylsilyl)cyclooctatetraenyl) has been synthesized by oxidation of the anionic sandwich complex Li[Pu(1,4-COT'')₂] (3) with anhydrous cobalt(II) chloride. The first crystal structure determination of an organoplutonium(IV) complex revealed an asymmetric sandwich structure for 4 where one COT'' ring is 1,3-substituted while the other retains the original 1,4-substitution pattern. The electronic structure of 4 has been elucidated by a computational study, revealing a probable cause for the unexpected silyl group migration. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] We report the uranium(VI) carbene imido oxo complex [U(BIPM^TMS)(NMes)(O)(DMAP)₂] (5, BIPM^TMS=C(PPh₂NSiMe₃)₂; Mes=2,4,6-Me₃C₆H₂; DMAP=4-(dimethylamino)pyridine) which exhibits the unprecedented arrangement of three formal multiply bonded ligands to one metal center where the coordinated heteroatoms derive from different element groups. This complex was prepared by incorporation of carbene, imido, and then oxo groups at the uranium center by salt elimination, protonolysis, and two-electron oxidation, respectively. The oxo and imido groups adopt axial positions in a T-shaped motif with respect to the carbene, which is consistent with an inverse trans-influence. Complex 5 reacts with tert-butylisocyanate at the imido rather than carbene group to afford the uranyl(VI) carbene complex [U(BIPM^TMS)(O)₂(DMAP)₂] (6). (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] An intriguing structural transition from the quasi-planar form of B₁₂ cluster upon the interaction with lithium atoms is reported. High-level computations show that the lowest energy structures of LiB₁₂, Li₂B₁₂, and Li₃B₁₂ have quasi-planar (C_s), tubular (D_6d), and cage-like (C_s) geometries, respectively. The energetic cost of distorting the B₁₂ quasi-planar fragment is overcompensated by an enhanced electrostatic interaction between the Li cations and the tubular or cage-like B₁₂ fragments, which is the main reason of such drastic structural changes, resulting in the smallest tubular (Li₂B₁₂) and cage-like (Li₃B₁₂) boron structures reported to date. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] The reaction of (C_5Me_5)_2Th(CH_3)_2 with the phosphonium salts [CH_3PPh_3]X (X=Cl, Br, I) was investigated. When X=Br and I, two equivalents of methane are liberated to afford (C_5Me_5)_2Th[CHPPh_3]X, rare terminal phosphorano-stabilized carbenes with thorium. These complexes feature the shortest thorium-carbon bonds (∼2.30 Aa) reported to date, and electronic structure calculations show some degree of multiple bonding. However, when X=Cl, only one equivalent of methane is lost with concomitant formation of benzene from an unstable phosphorus(V) intermediate, yielding (C_5Me_5)_2Th[κ"2-(C,C"')-(CH_2)(CH_2)PPh_2]Cl. Density functional theory (DFT) investigations of the reaction energy profiles for [CH_3PPh_3]X, X=Cl and I showed that in the case of iodide, thermodynamics prevents the production of benzene and favors formation of the carbene. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] A stimuli-responsive lanthanide-based smart nanocomposite has been fabricated by supramolecular assembly and applied as an active material in multidimensional memory materials. Conjugation of the lanthanide complexes with carbon dots provides a stimuli response that is based on the modulation of the energy level of the ligand and affords microsecond-to-nanosecond fluorescence lifetimes, giving rise to intriguing memory performance in the spatial and temporal dimension. The present study points to a new direction for the future development of multidimensional memory materials based on inorganic-organic hybrid nanosystems. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)