Site-specific conjugation of ScFvs antibodies to nanoparticles by bioorthogonal strain-promoted alkyne-nitrone cycloaddition

Particularly suitable: An N-terminal serine mutant of anti-HER2 scFv antibody was conjugated to polymer-coated magnetofluorescent nanoparticles by strain-promoted alkyne-nitrone cycloaddition. The resulting nanoparticles (see scheme) proved effective in targeting and labeling HER2-positive breast cancer cells.     

Hole transfer dynamics from dye molecules to p-type NiO nanoparticles: effects of processing conditions

Hole transfer dynamics of Atto647N sensitized p-type NiO nanoparticle (NP) thin films is investigated using both ensemble-averaged and single-molecule spectroscopy techniques. The rate of hole transfer is dependent on the processing conditions and is enhanced when the NiO is pre-annealed in air as compared to vacuum. This is possibly due to an upward shift of the valence band of the semiconductor and an increase in the free energy for hole transfer as more Ni(2)O(3) are formed in the presence of air. The stretched exponential fluorescence decay profile of Atto647N on NiO NP suggests the presence of a distribution of hole transfer rates. This is in agreement with the observed emission lifetime and intensity fluctuations and non-monoexponential fluorescence decays for individual Atto647N molecules on NiO NP films. A plausible explanation for the heterogeneous hole transfer rates is an inhomogeneous distribution of (defect) sites on the metal oxide due to the processing conditions and a fluctuation in the intermolecular interaction.     

Dinuclear Pt(II)-bisphosphonate complexes: a scaffold for multinuclear or different oxidation state platinum drugs

Geminal bisphosphonates (BPs), used in the clinic for the treatment of hypercalcaemia and skeletal metastases, have been also exploited for promoting the specific accumulation of platinum antitumor drugs in bone tissue. In this work, the platinum dinuclear complex [{Pt(en)}(2)(μ-AHBP-H(2))](+) (1) (the carbon atom bridging the two phosphorous atoms carrying a 2-ammonioethyl and a hydroxyl group, AHBP-H(2)) has been used as scaffold for the synthesis of a Pt(II) trinuclear complex, [{Pt(en)}(3)(μ-AHBP)](+) (2), and a Pt(IV) adamantane-shaped dinuclear complex featuring an oxo-bridge, [{Pt(IV)(en)Cl}(2)(μ-O)(μ-AHBP-H(2))](+) (3) (X-ray structure). Compound 2 undergoes a reversible, pH dependent, rearrangement with a neat switch point around pH = 5.4. Compound 3 undergoes a one-step electrochemical reduction at E(pc) = -0.84 V affording compound 1. Such a potential is far lower than that of glutathione (-0.24 V), nevertheless compound 3 can undergo chemical reduction to 1 by GSH, most probably through a different (inner-sphere) mechanism. In vitro cytotoxicity of the new compounds, tested against murine glioma (C6) and human cervix (HeLa) and hepatoma (HepG2) cell lines, has shown that, while the Pt(IV) dimer 3 is inactive up to a concentration of 50 μM, the two Pt(II) polynuclear compounds 1 and 2 have a cytotoxicity comparable to that of cisplatin with the trinuclear complex 2 generally more active than the dinuclear complex 1.     

About the OH yield in the radiolysis of an aqueous/H2O2 system. Its optimisation for water treatment

Unless the radiolytic reducing species are neutralised or converted into oxidising species, an EB remediation system cannot be considered a true Advanced Oxidation Processes (AOP). A water/H₂O₂ system irradiated by UVC mercury lamps constitutes a widely used OH production method. Employing H₂O₂ in radiolysis as well, an enhancement of the oxidative efficiency of an EB treatment can be obtained. Pulse radiolysis measurements of an aerated aqueous/H₂O₂/KSCN system have been systematically undertaken to assess the optimal H₂O₂ concentration. By linearly fitting a competition kinetics relationship, it is found that the scavengeable extra-yield of OH is ΔG(OH)=0.24 μmol J^?1 (R=0,9958), while the maximum experimental yield is measured G(OH)_max=(0.52±0.02) μmol J^?1 when [H₂O₂]=5–10 mM. Exceeding these concentrations the OH yield drops off.     

New ternary germanides La4Mg5Ge6 and La4Mg7Ge6: crystal structure and chemical bonding

The synthesis, structural characterization, and chemical-bonding peculiarities of the two new polar lanthanum-magnesium germanides La(4)Mg(5)Ge(6) and La(4)Mg(7)Ge(6) are reported. The crystal structures of these intermetallics were determined by single-crystal X-ray diffraction analysis. The La(4)Mg(5)Ge(6) phase crystallizes in the orthorhombic Gd(4)Zn(5)Ge(6) structure type [Cmc2(1), oS60, Z = 4, a = 4.5030(7) ?, b = 20.085(3) ?, c = 16.207(3) ?, wR2 = 0.0451, 1470 F(2) values, 93 variables]. The La(4)Mg(7)Ge(6) phase represents a new structure type with a monoclinic unit cell [C2/m, mS34, Z = 2, a = 16.878(3) ?, b = 4.4702(9) ?, c = 12.660(3) ?, β = 122.25(3)°, wR2 = 0.0375, 1466 F(2) values, 54 variables]. Crystallographic analysis together with linear muffin-tin orbital band structure calculations reveals the presence of strongly bonded 3D polyanionic [Mg-Ge] networks balanced by positively charged La atoms in both stoichiometric compounds. The La(4)Mg(5)Ge(6) compound is related to Zintl phases, showing a prominent density of states pseudogap at the Fermi level. A distinctive feature of the La(4)Mg(5)Ge(6) structure is the presence of Ge-Ge covalent dumbbells; in La(4)Mg(7)Ge(6), the higher Mg content generates a polyanionic network consisting exclusively of Mg-Ge heterocontacts. Nevertheless, the frameworks of the two phases are structurally similar, as is highlighted in this work.     

Modification of Cross-Linked Rubber Particles by Free Radical Polymerization

The synthesis of polystyrene chains covalently bound to the surface of cross-linked rubber particles from recycled tires (ground tire rubber, GTR) was investigated via free radical polymerization in situ by using azobisisobutyronitrile (AIBN) and dibenzoyl peroxide (BPO) as initiators. Indeed, the graft polymerization provides a significant route to modify the physical and chemical properties of these particles allowing to improve their compatibility with other polymers. Polymerization reactions were carried out in bulk by changing the styrene/GTR ratio as well as the amount of free radical initiator. Appreciable amounts of polystyrene (PS) were grafted on GTR when BPO was used as confirmed by particle characterizations.     

Polar-Covalent Bonding Beyond the Zintl Picture in Intermetallic Rare-Earth Germanides

A comparative chemical bonding analysis for the germanides La₂MGe₆ (M=Li, Mg, Al, Zn, Cu, Ag, Pd) and Y₂PdGe₆ is presented, together with the crystal structure determination for M=Li, Mg, Cu, Ag. The studied compounds adopt the two closely related structure types oS72-Ce₂(Ga_0.1Ge_0.9)₇ and mS36-La₂AlGe₆, containing zigzag chains and corrugated layers of Ge atoms bridged by M species, with La/Y atoms located in the biggest cavities. Chemical bonding was studied by means of the quantum chemical position-space techniques QTAIM (quantum theory of atoms in molecules), ELI-D (electron localizability indicator), and their basin intersections. The new penultimate shell correction (PSC0) method was introduced to adapt the ELI-D valence electron count to that expected from the periodic table of the elements. It plays a decisive role to balance the Ge−La polar-covalent interactions against the Ge−M ones. In spite of covalently bonded Ge partial structures formally obeying the Zintl electron count for M=Mg²⁺, Zn²⁺, all the compounds reveal noticeable deviations from the conceptual 8−N picture due to significant polar-covalent interactions of Ge with La and M ≠ Li, Mg atoms. For M=Li, Mg a formulation as a germanolanthanate M[La₂Ge₆] is appropriate. Moreover, the relative Laplacian of ELI-D was discovered to reveal a chemically useful fine structure of the ELI-D distribution being related to polyatomic bonding features. With the aid of this new tool, a consistent picture of La/Y−M interactions for the title compounds was extracted.     

Photochemical nitrooxylation of methylbenzenes by cerium(IV) ammonium nitrate in acetonitrile

The photochemical reaction of substituted toluenes with CAN in CH₃CN leads to good yields of benzyl nitrates under very mild conditions.     

Semi-rigid analogues of the calcium antagonist verapamil: A molecular modelling study

Summary In this work the rigid-analogue approach has been used to obtain information on the active conformation(s) of the calcium antagonist verapamil. A series of semi-rigid analogues of verapamil were synthesized and their biological activities evaluated on guinea-pig heart and aorta. These molecules were analysed by means of molecular modelling techniques.On the basis of the pharmacological profile and conformational analysis of these compounds, two different models for negative inotropic and negative chronotropic activity are proposed. The two actions seem to be due to conformations of the molecules which differ in the orientation of their phenylethylamino groups.