Preparation and characterization of conjugated polymers made by postpolymerization reactions of alternating polyketones

Conjugated polymers possessing a poly(2,5-dimethylene-2,5-dihydrofuran) backbone were prepared through postpolymerization reaction of styrenic polyketones with bromine in one-pot reactions. The modification is proposed to proceed via condensation of two repeating units to form a fully characterized polymer with a poly(2,5-dimethylenetetrahydrofuran) backbone. Subsequent bromination and elimination of HBr yield a polymer with a fully conjugated carbon backbone. The new conjugated polymers were characterized by NMR, IR, and UV-vis spectroscopies and by CV. These polymers have strong absorption in the visible region, with the absorption peaks shifted to the NIR region upon doping with acids. The ease of the synthesis of the starting polyketone and of the modifications allows large-scale preparation of those conjugated polymers.     

Influence of substrate surface chemistry on the performance of top-gate organic thin-film transistors

Organic thin-film transistor (OTFT) performance depends on the chemical characteristics of the interface between functional semiconductor/dielectric/conductor materials. Here we report for the first time that OTFT response in top-gate architectures strongly depends on the substrate chemical functionalization. Depending on the nature of the substrate surface, dramatic variations and opposite trends of the TFT threshold voltage (~±50 V) and OFF current (10(5)×!) are observed for both p- and n-channel semiconductors. However, the field-effect mobility varies only marginally (~2×). Our results demonstrate that the substrate is not a mere passive mechanical support.     

Real-time electrochemical monitoring of isothermal helicase-dependent amplification of nucleic acids

We described an electrochemical method to monitor in real-time the isothermal helicase-dependent amplification of nucleic acids. The principle of detection is simple and well-adapted to the development of portable, easy-to-use and inexpensive nucleic acids detection technologies. It consists of monitoring a decrease in the electrochemical current response of a reporter DNA intercalating redox probe during the isothermal DNA amplification. The method offers the possibility to quantitatively analyze target nucleic acids in less than one hour at a single constant temperature, and to perform at the end of the isothermal amplification a DNA melt curve analysis for differentiating between specific and non-specific amplifications. To illustrate the potentialities of this approach for the development of a simple, robust and low-cost instrument with high throughput capability, the method was validated with an electrochemical system capable of monitoring up to 48 real-time isothermal HDA reactions simultaneously in a disposable microplate consisting of 48-electrochemical microwells. Results obtained with this approach are comparable to that obtained with a well-established but more sophisticated and expensive fluorescence-based method. This makes for a promising alternative detection method not only for real-time isothermal helicase-dependent amplification of nucleic acid, but also for other isothermal DNA amplification strategies.     

DOTAGA–Anhydride: A Valuable Building Block for the Preparation of DOTA‐Like Chelating Agents

A DOTA derivative that contains an anhydride group was readily synthesized by reacting DOTAGA with acetic anhydride and its reactivity was investigated. Opening the anhydride with propylamine led to the selective formation of one of two possible regioisomers. The structure of the obtained isomer was unambiguously determined by 1D and 2D NMR experiments, including COSY, HMBC, and NOESY techniques. This bifunctional chelating agent offers a convenient and attractive approach for labeling biomolecules and, more generally, for the synthesis of a large range of DOTA derivatives. The scope of the reaction was extended to prepare DOTA‐like compounds that contained various functional groups, such as isothiocyanate, thiol, ester, and amino acid moieties. This versatile building block was also used for the synthesis of a bimodal tag for SPECT or PET/optical imaging.     

Green chemistry: solvent- and metal-free Prins cyclization. Application to sequential reactions

Prins cyclization between a homoallylic alcohol and an aldehyde, promoted by trimethylsilyl halide, afforded 4-halo-tetrahydropyrans with good to excellent yields. Thanks to the absence of the solvent and metal, the THP thus obtained have been implicated without purification in several other reactions, in a sequential way, affording in particular new indole derivatives.     

Homogeneous electrochemical monitoring of exonuclease III activity and its application to nucleic acid testing by target recycling

A simple and fast electrochemical nucleic acid assay based on a target recycling strategy and the release of a double-stranded DNA intercalating redox probe upon digestion of a specific duplex by exonuclease III is demonstrated.     

DOTAGA-anhydride: a valuable building block for the preparation of DOTA-like chelating agents

A DOTA derivative that contains an anhydride group was readily synthesized by reacting DOTAGA with acetic anhydride and its reactivity was investigated. Opening the anhydride with propylamine led to the selective formation of one of two possible regioisomers. The structure of the obtained isomer was unambiguously determined by 1D and 2D NMR experiments, including COSY, HMBC, and NOESY techniques. This bifunctional chelating agent offers a convenient and attractive approach for labeling biomolecules and, more generally, for the synthesis of a large range of DOTA derivatives. The scope of the reaction was extended to prepare DOTA-like compounds that contained various functional groups, such as isothiocyanate, thiol, ester, and amino acid moieties. This versatile building block was also used for the synthesis of a bimodal tag for SPECT or PET/optical imaging.