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Polymer thin film memtransistors were realized with a solution-processed bilayer structure, which manifested as the ion-carrier exchange heterojunction. The temporal and spatial evolution of the ion-carrier exchange in the devices resulted in the memristive characteristics in both vertical and horizontal directions, and the effective horizontal conductivity could be several orders higher than the vertical one. The device features may pave a promising way for emulating synaptic interactions based on a polymer functional thin film.

A hybrid memristor based on the bilayer structure of indium gallium zinc oxide (IGZO)/polyvinyl alcohol (PVA) is developed, which demonstrates device state updates in an analog manner with high reliability. The IGZO/PVA heterojunction is crucial for the realization of the memristive characteristics, presumably associated with oxygen ion redistribution across the IGZO/PVA interface. The hybrid memristor may act as an electronic synapse, being capable of emulating synaptic potentiation with good linearity, synaptic depression, and paired-pulse facilitation. It highlights potential applications of the oxide-polymer heterojunction in the exploration of neuromorphic devices.

A paradigm for soft memtransistor is demonstrated based on the ion transfer interface, consisting of an ion-rich semiconducting polymer layer on the top and a gelatin dielectric for receiving ions on the bottom. The flexible polymer memtransistor acted as an analog-type memristor without gating, and its memristive strength could be largely modulated by applying gate voltage. It is proposed that the ion redistribution across the ion transfer interface can modify the hole doping level in the polymer layer, which is responsible for the tunable memristive characteristics. Different levels of synaptic potentiation and depression were successfully emulated using the polymer memtransistor, and it is promising to extend the emulation to multi-terminal heterosynaptic plasticity.

Ultraviolet (UV) monitoring has wide applications in diverse fields, where sensitive photodetection and recording of UV exposure history are often simultaneously required. A new strategy is herein developed to achieve solar-blind UV monitoring. Based on organic field-effect transistors (OFETs), nonvolatile memories with both p-type or n-type organic active layers demonstrate selective and storable UV response. These OFET memories are sensitive only to solar-blind UV light of 254 nm, and have no response to UV light of 365 nm or visible light. The photoresponsive signal can be recorded in a nonvolatile manner with excellent retention and rewritable capability, which integrates solar-blind UV detection and memory into a single device. These OFET memories are well compatible with flexible substrates, and thus could be very useful for portable and/or wearable UV dosimetry. The conventional bandgap photoexcitation mechanism is not applicable to the this case, and a UV-induced interfacial excitation mechanism is proposed to interpret the device features.

High-performance pentacene-based organic field-effect transistor nonvolatile memories, using polystyrene as a tunneling dielectric and Au nanoparticles as a nano-floating-gate, show parallelogram-like transfer characteristics with a featured transition point. The transition voltage at the transition point corresponds to a threshold electric field in the tunneling dielectric, over which stored electrons in the nano-floating-gate will start to leak out. The transition voltage can be modulated depending on the bias configuration and device structure. For p-type active layers, optimized transition voltage should be on the negative side of but close to the reading voltage, which can simultaneously achieve a high ON/OFF ratio and good memory retention.

Achiral N-acylaziridines are isomerized to optically active N-acyl-allylamines in ee's of up to 95% by catalytic amounts of cob(I)alamin in MeOH.

Achiral N-acylaziridines are isomerized to optically active N-acyl-allylamines in ee's of up to 95% by catalytic amounts of cob(I)alamin in MeOH.

A prostaglandin F2α precursor containing all structural features from C6 to C20 with 8R, 9S, 11R and 12R chirality is obtained by the one step formation of two C-C bonds in the B12-catalyzed radical cyclization-addition sequence starting from a chiral cyclopentene bromoacetal and l-octyne-3-one. The B12-catalyzed radical cyclization-elimination sequence of a chiral cyclopentene precursor leads to (-)-(3aR,6aS)-3,3a,6,6a-tetrahydro-2H-cyclopenta abfuran-2-one. Its (+)-(3aS,6aR-enantiomer is obtained via B12-catalyzed, enantio- selective isomerization of cyclopentene oxide to (R)-2-cyclopentene-l-ol followed by the B12-catalyzed radical cyclization-elimination sequence of its bromoacetal.

Achiral epoxides are isomerized to optically active allylic alcohols under the influence of catalytical amounts of cob(I) alamin in protic polar solvents.

Vitamin B12 and related metal complexes act as mediators in the electron transfer from the electron source (chemical reducing agent or cathode in electrochemical reductions) to an electrophilic substrate R-X (R-X = alkyl-, vinyl- or acyl- derivative) [1]. On B12-catalyzed reduction R-X is transformed to the radical R. or the carbanion R− (depending on the structure of R and the reaction conditions) either directly or via an organometallic intermediate. The Co,C-bond of the organocobalamin intermediate is cleaved as a consequence of redox-reactions [2], thermic or photochemical activation [3].

Achiral epoxides are isomerized to optically active allylic alcohols under the influence of catalytical amounts of cob(I) alamin in protic polar solvents.