Electropolymerized o‐Phenylenediamine on Graphite Promoting the Electrochemical Detection of Nafcillin

By combining molecular modelling and electrochemistry we envision the creation of modified electrodes tailored for a more sensitive and selective detection of a single analyte. In this study we report on a graphite screen printed electrode modified with electropolymerized o‐phenylenediamine, selected by rational design, which promotes the detection of nafcillin (NAF), an antibiotic. Parameters such as monomer concentration, pH and number of electropolymerization cycles were optimized to obtain the highest current signal for the target upon amperometric detection. NAF identification was based on the redox process at +1.1 V (vs pseudo Ag), ascribed to the oxidation of the C‐7 side chain. With the optimized modification protocol, a two‐fold increase in nafcillin signal could be obtained: the calibration plot in 0.1 M Britton‐Robinson buffer pH 4 showed a limit of detection of 80 nM with improved sensitivity and reproducibility (RSD<5 %) compared to the detection at non‐modified electrodes.     

Copper‐Catalyzed Triboration of Terminal Alkynes Using B2pin2: Efficient Synthesis of 1,1,2‐Triborylalkenes

We report herein the catalytic triboration of terminal alkynes with B₂pin₂ (bis(pinacolato)diboron) using readily available Cu(OAc)₂ and PⁿBu₃. Various 1,1,2‐triborylalkenes, a class of compounds that have been demonstrated to be potential matrix metalloproteinase (MMP‐2) inhibitors, were obtained directly in moderate to good yields. The process features mild reaction conditions, a broad substrate scope, and good functional group tolerance. This copper‐catalyzed reaction can be conducted on a gram scale to produce the corresponding 1,1,2‐triborylalkenes in modest yields. The utility of these products was demonstrated by further transformations of the C?B bonds to prepare gem‐dihaloborylalkenes (F, Cl, Br), monohaloborylalkenes (Cl, Br), and trans‐diaryldiborylalkenes, which serve as important synthons and have previously been challenging to prepare.     

Synthesis,Photophysical and Electronic Properties of New Red-to-NIR Emitting Donor–Acceptor Pyrene Derivatives

We synthesized new pyrene derivatives with strong bis(para-methoxyphenyl)amine donors at the 2,7-positions and n-azaacene acceptors at the K-region of pyrene. The compounds possess a strong intramolecular charge transfer, leading to unusual properties such as emission in the red to NIR region (700 nm), which has not been reported before for monomeric pyrenes. Detailed photophysical studies reveal very long intrinsic lifetimes of >100 ns for the new compounds, which is typical for 2,7-substituted pyrenes but not for K-region substituted pyrenes. The incorporation of strong donors and acceptors leads to very low reduction and oxidation potentials, and spectroelectrochemical studies show that the compounds are on the borderline between localized Robin-Day class-II and delocalized Robin-Day class-III species.     

Lyapunov exponent,Liao perturbation and persistence

Science China Mathematics - Consider a C1 vector field together with an ergodic invariant probability that has ? nonzero Lyapunov exponents. Using orthonormal moving frames along a generic...     

Isometric Uncertainty Relations

Journal of Statistical Physics - We generalize the link between fluctuation theorems and thermodynamic uncertainty relations by deriving a bound on the variance of fluxes that satisfy an isometric...