The synthesis of fully conjugated sp 2 -carbon covalent organic frameworks (COF) is extremely challenging given the difficulty of the formation of very stable carbon-carbon double bonds (-C=C-). Here,w er eport the successful preparation of a2 DC OF (TP-COF) based on triazine as central planar units bridged by sp 2 -carbon linkers through the -C = Ccondensation reaction. High-resolution-transmission electron microscopy( HRTEM) clearly confirmed the tessellated hexagonal pore structure with ap ore center-to-center distance of 2nm. Powder X-rayd iffraction (PXRD) together with structural simulations revealed an AA stacking mode of the obtained layered structure.T P-COF turned out to be an excellent semiconductor material with aL UMO energy of À3.23 eV and aband gap of 2.36 eV.Excitingly,this novel sp 2carbon conjugated TP-COF exhibited unprecedented coenzyme regeneration efficiency and can significantly boost the coenzyme-assisted synthesis of l-glutamate to arecord-breaking 97 %yield within 12 minutes.Long-range p-conjugated two-dimensional (2D) materials have received considerable attention in recent years and present ar ange of unique advantages over traditional polymeric materials. [1][2][3][4][5][6][7] In particular, the topological arrangement of aromatic units propagating in two spatial directions equips them with superior (photo-)electronic and magnetic properties. [8][9][10] However,t he delicate control over specific arrangements of functional units to obtain highly ordered 2D materials is still ag reat challenge. [11][12][13][14] Covalent organic frameworks (COFs) take advantage of the structural selfhealing properties stemming from dynamic covalent bond formation. [15][16][17][18][19][20][21] This advancement has made it possible to synthesize well-defined 2D structures with diverse functionalities.A mong all synthetic strategies of COFs,t he most frequently used dynamic covalent-bond-formations trategies are the Schiff base condensation reaction and the boronate ester bond formation. Despite the fact that the extended pconjugation can propagate through the -N = C-double bonds in the Schiff base structure,t he imine-linkage displays relatively poor stability and weak electron delocalization. To overcome this limitation, researchers have been actively exploring new reactions to construct fully conjugated COFs with an optimal electron delocalization. [22][23][24][25][26][27][28] However,examples of fully conjugated imine-free COFs with sp 2 -carbon double bond structures are still rare because it is extremely difficult to form -C = C-bonds via reversible coupling reactions and simultaneously gain the desired conjugation as well as the refined crystallinity within the COF structure.Recently, Jiang et al. and Feng et al. successfully constructed conjugated 2D COFs bearing -C = C-linkage by using Knoevenagel polycondensation. [29][30][31][32] Ther eported sp 2 -carbon linked 2D COFs were demonstrated to have excellent electrochemical and charge-transfer properties.Thee nhanced electron delocalization of sp 2...

Over the past decade, the use of photocatalysts (PCs) in controlled polymerization has brought new opportunities in sophisticated macromolecular synthesis. However, the selection of PCs in these systems has been typically based on laborious trialand-error strategies. To tackle this limitation, computer-guided rational design of PCs based on knowledge of structure-property-performance relationships has emerged. These rational strategies provide rapid and economic methodologies for tuning the performance and functionality of a polymerization system, thus providing further opportunities for polymer science. This review provides an overview of PCs employed in photocontrolled polymerization systems and summarizes their progression from early systems to the current state-of-the-art. Background theories on electronic transitions are also introduced to establish the structure-property-performance relationships from a perspective of quantum chemistry. Typical examples for each type of structure-property relationships are then presented to enlighten future design of PCs for photocontrolled polymerization. CONTENTS Glossary 5512 References 5513

The influence of top electrode material on the resistive switching properties of ZrO 2 -based memory film using Pt as a bottom electrode was investigated in this letter. In comparison with Pt/ZrO 2 /Pt and Al/ZrO 2 /Pt devices, the Ti/ZrO 2 /Pt device exhibits different resistive switching current-voltage (I-V ) curve, which can be traced and reproduced by a dc voltage more than 1000 times only showing a little decrease of resistance ratio between high and low resistance states. Furthermore, the broad dispersions of resistive switching characteristics in the Pt/ZrO 2 /Pt and Al/ZrO 2 /Pt devices are generally observed during successive resistive switching, but those dispersions are suppressed by the device using Ti as a top electrode. The reliability results, such as cycling endurance and continuous readout test, are also presented. The write-read-erase-read operations can be over 10 4 cycles without degradation. No data loss is found upon successive readout after performing various endurance cycles.Index Terms-Nonvolatile memory, resistive random access memory (RRAM), resistive switching, ZrO 2 .