Pulsed laser ablation of La0.5Sr0.5CoO3

The ablation process of La_0.5Sr_0.5CoO₃ by a spatial uniform 248 nm excimer laser beam has been characterized. Ablation rates, changes in the target surface morphology and composition have been studied as a function of the laser fluence. The dependence of the ablation rate on the laser fluence has been explained by a model based on plasma absorption. The threshold fluence for complete dissociation of the surface has been determined and is found equal to 0.7 J/cm². Above this threshold, a steady-state target surface condition is obtained within 30 pulses. Below the threshold fluence, CoO nuclei form, which have a pronounced effect on the target composition and morphology. In addition, ellipsometric and reflectance spectra have been measured in the photon energy range of 1.8 to 5.0 eV.     

Dodecaindane (tBu3Si)8In12—A Compound with an In12 Deltapolyhedron Framework

A unique feature among polyhedron frameworks of boron group elements is exhibited by the In₁₂ framework of the black-violet dodecaindane R^*₈In₁₂ (R*=SitBu₃), which can be obtained by the thermolysis of R^*₂In−InR^*₂. The molecular structure of R^*₈In₁₂ (tBu groups omitted in picture shown) can be described as a combination of two R^*₄In₆ octahedral building blocks and can thus be classified as a conjuncto dodecaindane.     

Synthesis,Characterization, and Electron-Transfer Properties of Ferrocene–BODIPY–Fullerene Near-Infrared-Absorbing Triads: Are Catecholopyrrolidine-Linked Fullerenes a Good Architecture to Facilitate Electron-Transfer?

A series of covalent ferrocene–BODIPY–fullerene triads with the ferrocene groups conjugated to the BODIPY π-system and the fullerene acceptor linked at the boron hub by a common catecholpyrrolidine bridge were prepared and characterized by 1D and 2D NMR, UV/Vis, steady-state fluorescence spectroscopy, high-resolution mass spectrometry, and, for one of the derivatives, X-ray crystallography. Redox processes of the new compounds were investigated by electrochemical (CV and DPV) methods and spectroelectrochemistry. DFT calculations indicate that the HOMO in all triads was delocalized between ferrocene and BODIPY π-system, the LUMO was always fullerene-centered, and the catechol-centered occupied orbital was close in energy to the HOMO. TDDFT calculations were indicative of the low-energy, low-intensity charge-transfer bands originated from the ferrocene–BODIPY core to fullerene excitation, which explained the similarity of the UV/Vis spectra of the ferrocene–BODIPY dyads and ferrocene–BODIPY–fullerene triads. Photophysical properties of the new triads as well as reference BODIPY–fullerene and ferrocene–BODIPY dyads were investigated by pump-probe spectroscopy in the UV/Vis and NIR spectral regions following selective excitation of the BODIPY-based antenna. Initial charge transfer from the ferrocene to the BODIPY core was shown to outcompete sub-100 fs deactivation of the excited state mediated by the catechol bridge. However, no subsequent electron transfer to the fullerene acceptor was observed. The initial charge separated state relaxes by recombination with a time constant of 150–380 ps.     

Real-time control of antibody loading during protein A affinity chromatography using an on-line assay.

We show that an on-line chromatographic assay can reliably control antibody loading in real-time during protein A affinity chromatography purification of a recombinant antibody from clarified Chinese hamster ovary cell culture fluid. The on-line assay directly sampled preparative column effluent and provided real-time measurement of antibody breakthrough during loading. The on-line assay used protein A immobilized on perfusion chromatography media, equilibrated with phosphate-buffered saline at pH 7.2 and eluted with phosphate-buffered saline at pH 2.2. The assay reliably ended loading at 1% breakthrough with minimal yield loss. Reproducible yield and purity were obtained over 23 consecutive cycles. Yield remained constant while breakthrough capacity and the antibody concentration in the load changed.     

Hexasupersilyloctaindane (tBu3Si)6In8— A Compound with a Novel In8 Cluster Framework

A doubly capped In ₆ octahedron characterizes the structure of the dark green octaindane (tBu₃Si)₆In₈ (see picture), which is obtained from (C₅Me₅)In and tBu₃SiNa in pentane at −78°C. In1/In1′ are the capping atoms, and In2/In2′ form the apexes of the stretched In₆ octahedron. Thus, in agreement with the results of ab initio calculations, the compound can be classified as a hypoprecloso-indane.     

Structure of Germanium Treated in a Planetary Mill

Physics of the Solid State - The structure of a powder germanium treated in a planetary mill in the presence of small (5–25%) additions of diamond powder has been studied by high-resolution...