Access to New Endoperoxide Derivatives by Electrochemical Oxidation of Substituted 3‐Azabicyclo[4.1.0]hept‐4‐enes

A series of substituted 3‐azabicyclo[4.1.0]hept‐4‐ene derivatives were prepared and analysed by cyclic voltammetry. Preparative aerobic electrochemical oxidation reactions were then carried out. Three original endoperoxides were isolated, characterised and subjected to antimalarial and cytotoxicity activity assays.     

Highly efficient metal‐free organic catalysts to design new Environmentally‐friendly starch‐based blends

A one‐step process is reported to directly synthesize blends of poly(trimethylene carbonate) (PTMC) with a modified granular starch. Trimethylene Carbonate (TMC) ring‐opening polymerization is performed in the presence of native starch particles in bulk conditions at 150 °C and the efficiency of metal‐free organic catalysts (TBD and phosphazene superbases P1‐t‐Oct, P2‐t‐bu, and P4‐t‐bu) are investigated to replace the organo‐metallic stannous octanoate initiator. TMC monomer is successively converted into PTMC and the robustness of organic catalysts is highlighted with significant activities at very low concentrations (<100 ppm), where stannous octanoate is inefficient. Reactivity of starch toward TMC ROP is deeply investigated by NMR techniques and a starch‐graft‐PTMC is indirectly evidenced. Starch substitution degree reaches 0.9% indicating that PTMC grafting only occurs at the surface of swollen granular starch. PTMC graft length from the starch surface remained low in the range 2–12 and model ROP reactions highlight the role of TMC hydrolysis on PTMC graft length. Despite low PTMC grafts, a fine dispersion of intact starch particles into the PTMC matrix is evidenced. Consequently, metal‐free organic catalysts at low concentrations are promising candidates for synthesizing blends of PTMC with high loadings of surface‐modified starch (32% by weight) in 2 min within a one‐step process. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 493–503     

Charge transport and contact resistance in coplanar devices based on colloidal polyaniline dispersion

The charge transport properties of thin films prepared from colloidal dispersion of polyaniline stabilized by poly(N‐vinylpyrrolidone) (PANI/PVP) have been investigated. The electrical characterization of coplanar device comprising of gold electrodes and PANI/PVP film deposited by spin coating served to gain insights into the contact and bulk resistance. The films prepared from PANI/PVP colloidal dispersion show high stability over a large temperature range. Temperature dependent measurements in the range from 90 to 350 K reveal that the charge transport can be described by a three‐dimensional variable‐range hopping mechanism as the dominant mode in the films. The stability of the films cast from dispersion within a large temperature range opens the possibility of the application as a polymer semiconductor layer in sensors and charge‐transport interlayer in organic solar cells. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1710–1716     

In situ single‐crystal to single‐crystal (SCSC) transformation of the one‐dimensional polymer catena‐poly[[diaqua(sulfato)copper(II)]‐μ2‐glycine] into the two‐dimensional polymer poly[μ2‐glycine‐μ4‐sulfato‐copper(II)]

The one‐dimensional coordination polymer catena‐poly[diaqua(sulfato‐κO)copper(II)]‐μ₂‐glycine‐κ²O:O′], [Cu(SO₄)(C₂H₅NO₂)(H₂O)₂]_n, (I), was synthesized by slow evaporation under vacuum of a saturated aqueous equimolar mixture of copper(II) sulfate and glycine. On heating the same blue crystal of this complex to 435 K in an oven, its aspect changed to a very pale blue and crystal structure analysis indicated that it had transformed into the two‐dimensional coordination polymer poly[(μ₂‐glycine‐κ²O:O′)(μ₄‐sulfato‐κ⁴O:O′:O′′:O′′)copper(II)], [Cu(SO₄)(C₂H₅NO₂)]_n, (II). In (I), the Cu^II cation has a pentacoordinate square‐pyramidal coordination environment. It is coordinated by two water molecules and two O atoms of bridging glycine carboxylate groups in the basal plane, and by a sulfate O atom in the apical position. In complex (II), the Cu^II cation has an octahedral coordination environment. It is coordinated by four sulfate O atoms, one of which bridges two Cu^II cations, and two O atoms of bridging glycine carboxylate groups. In the crystal structure of (I), the one‐dimensional polymers, extending along [001], are linked via N—H...O, O—H...O and bifurcated N—H...O,O hydrogen bonds, forming a three‐dimensional framework. In the crystal structure of (II), the two‐dimensional networks are linked via bifurcated N—H...O,O hydrogen bonds involving the sulfate O atoms, forming a three‐dimensional framework. In the crystal structures of both compounds, there are C—H...O hydrogen bonds present, which reinforce the three‐dimensional frameworks.     

Affinity capillary electrophoresis to evaluate the complex formation between poliovirus and nanobodies

It was demonstrated that nanobodies with an in vitro neutralizing activity against poliovirus type 1 interact with native virions. Here, the use of capillary electrophoresis was investigated as an alternative technique for the evaluation of the formation of nanobody–poliovirus complexes, and therefore predicting the in vitro neutralizing activity of the nanobodies. The macromolecules are preincubated offline in a specific nanobody‐to‐virus ratio and analyzed by capillary electrophoresis with UV detection. At low nanobody‐to‐virus ratios, a clear shift in migration time of the viral peak was observed. A broad peak was obtained, indicating the presence of a heterogeneous population of nanobody–virion complexes, caused by the binding of different numbers of nanobodies to the virus particle. At elevated nanobody‐to‐virus ratios, a cluster of peaks appeared, showing an additional increase in migration times. It was shown that, at these high molar excesses, aggregates were formed. The developed capillary electrophoresis method can be used as a rapid, qualitative screening for the affinity between poliovirus and nanobodies, based on a clearly visible and measurable shift in migration time. The advantages of this technique include that there is no need for antigen immobilization as in enzyme‐linked immunosorbent assays or surface plasmon resonance for the use of radiolabeled virus or for the performance of labor‐ and time‐intensive plaque‐forming neutralization assays.