Development of Predictive QSPR Model of the First Reduction Potential from a Series of Tetracyanoquinodimethane (TCNQ) Molecules by the DFT (Density Functional Theory) Method

In this work, which consisted to develop a predictive QSPR (Quantitative Structure-Property Relationship) model of the first reduction potential, we were particularly interested in a series of forty molecules. These molecules have constituted our database. Here, thirty molecules were used for the training set and ten molecules were used for the test set. For the calculation of the descriptors, all molecules have been firstly optimized with a frequency calculation at B3LYP/6-31G(d,p) theory level. Using statistical analysis methods, a predictive QSPR (Quantitative Structure-Property Relationship) model of the first reduction potential dependent on electronic affinity (EA) only have been developed. The statistical and validation parameters derived from this model have been determined and found interesting. These different parameters and the realized statistical tests have revealed that this model is suitable for predicting the first reduction potential of future TCNQ (tetracyanoquinodimethane) of this same family belonging to its applicability domain with a 95% confidence level.

DPA(TCNQ)_2的烧孔阈值电压对脉宽的依赖关系

合成了一种新的二元电荷转移复合物DPA(TCNQ)2(二丙胺-7,7,8,8-四氰基对亚甲基苯醌),并得到了其单晶ab面的STM高分辨图像,表面晶格常数与体相晶格常数的XRD数据完全一致.用STM成功地写入了5×5的信息点阵,并在5.1μm×5.1μm的面积上写入更大规模的信息点阵,写入的可靠性和稳定性都很高.实验发现,烧孔阈值电压强烈依赖于脉宽,这一现象不支持场致蒸发的机理.理论分析表明,它支持热化学烧孔的机理.

Atomic force microscopy investigation of growth process of organic TCNQ aggregates on SiO_2 and mica substrates

Deposition patterns of tetracyanoquinodimethane （TCNQ） molecules on different surfaces are investigated by atomic force microscopy. A homemade physical vapour deposition system allows the better control of molecule deposition. Taking advantage of this system, we investigate TCNQ thin film growth on both SiO2 and mica surfaces. It is found that dense island patterns form at a high deposition rate, and a unique seahorse-like pattern forms at a low deposition rate. Growth patterns on different substrates suggest that the fractal pattern formation is dominated by molecule-molecule interaction. Finally, a phenomenal ＂two-branch＂ model is proposed to simulate the growth process of the seahorse pattern.

High Electrical Conductivity and Conspicuous Phase Transitions in Single Crystals of K-TCNQ

This paper is to report the temperature dependent electrical conductivity of single crystals of radical ion salt (RIS) potassium-TCNQ (K-tetracyanoquino- dimethane) in a wide range of temperatures from 30 to 500 K. This RIS is quasi-one-dimensional in nature. These single crystals of K-TCNQ are grown by different methods like electrochemical, solution growth and diffusion method. Activation energy is determined for the sample in different temperature regions and found different values. More than one semiconductor to metal phase transition is observed in the studied samples during electrical measurements below and above room temperature. All the features observed in the studied samples are analyzed in the framework of their molecular structure as well as under different effects like disorder, impurity, Coulomb interaction, charge density wave (CDW), scattering and 3-D effects etc.

Ni(OH)_(2) nanoparticles encapsulated in conductive nanowire array for high-performance alkaline seawater oxidation

Design and development of high-efficiency and durable oxygen evolution reaction(OER)electrocatalysts is crucial for hydrogen production from seawater splitting.Herein,we report the in situ electrochemical conversion of a nanoarray of Ni(TCNQ)2(TCNQ=tetracyanoquinodimethane)on graphite paper into Ni(OH)_(2) nanoparticles confined in a conductive TCNQ nanoarray(Ni(OH)_(2)-TCNQ/GP)by anode oxidation.The Ni(OH)_(2)-TCNQ/GP exhibits high OER performance and demands overpotentials of 340 and 382 mV to deliver 100 mA·cm^(−2) in alkaline freshwater and alkaline seawater,respectively.Meanwhile,the Ni(OH)_(2)-TCNQ/GP also demonstrates steady long-term electrochemical durability for at least 80 h under alkaline seawater.

Ultra-small Cu nanoparticles embedded in N-doped carbon arrays for electrocatalytic CO2 reduction reaction in dimethylformamide

The development of heterogeneous catalysts with a well-defined micro structure to promote their activity and stability for electrocatalyfic CO2 reduction has been shown to be a promising strategy. In this work, Cu nanoparticles （- 4 nm in diameter） embedded in N-doped carbon （Cu@NC） arrays were fabricated by thermal decomposition of copper tetracyanoquinodimethane （CuTCNQ） under N2. Compared to polycrystalline copper electrodes, the Cu@NC arrays provide a significantly improved number of catalytically active sites. This resulted in a 0.7 V positive shift in onset potential, producing a catalytic current density an order magnitude larger at a potential of -2.7 V vs. Fc/Fc＋ （Fc = ferrocene） in dimethylformamide （DMF）. By controlling the water content in the DMF solvent, the CO2 reduction product distribution can be tuned. Under optimal conditions （0.5 vol.% water）, 64% HCOO^-, 20% CO, and 13% H2 were obtained. The Cu@NC arrays exhibited excellent catalytic stability with only a 0.5% decrease in the steady-state catalytic current during 6 h of electrolysis. The three-dimensional （3D） array structure of the Cu@NC was demonstrated to be effective for improving the catalytic activity of copper based catalysts while maintaining long-term catalytic stability.