The Photovoltage-gas Sensitive Properties of 7,7,8,8-Tetracyanoquinodimethane(TCNQ)

In this paper, surface photovoltage technique (SPV) was applied to the study of photovoltaic and gas sensitive properties of TCNQ polycrystal. It was found that SPV shows two peaks at 390 nm(P1) and 480 nm (P2) in the ultraviolet-visible range. And they are opposite in phase. The results of gaseous adsorption confirm that P, shows the acceptor characteristics, while PI shows that of donor. During adsorption, donor gas interacts with conjugated II * orbital, acceptor gas with the terminal group C=N .     

Anion-Radical Salts of 7,7,8,8-Tetracyanoquinodimethane (TCNQ) with Cations Based on Amino-Chloropyridines

Anion-radical salts of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with N-methyl-2-amino-5-chloropyridinium and N-methyl-2-chloro-3-aminopyridinium cations of simple and complex compositions were synthesized and studied. The salt (N?CH₃?2?Cl₃NH₂?Py)(TCNQ) is electrically conducting and thermally stable up to 340°C. This enables use of this anion-radical salt in electronics of organic materials.

     

Interactions of Ag Particles Stabilized by 7,7,8,8-Tetracyanoquinodimethane with Olefin Molecules in Poly(ether-block-amide)

In this study, to use a stabilized carrier, silver nanoparticles (AgNPs) were used as carriers and electron acceptors were added to activate the surface of AgNPs as olefin carriers. In addition, poly(ether-block-amide) (PEBAX), consisting of polyamide (hard segments) and polyether (soft segments), was investigated for the correlation of the between-segments ratio related to the stability of AgNPs and separation performance. As a result, contrary to the expectation that high permeance would be observed in PEBAX-1657/AgNPs/7,7,8,8-tetracyanoquinodimethane (TCNQ) membrane, which had a higher ratio of polyether soft segment, the PEBAX-5513/AgNPs/TCNQ membrane, which had a relatively high proportion of polyamide, showed a higher permeance without difference in selectivity. These unexpected data were attributable to the fact that the relatively abundant amount of PA groups in PEBAX-5513 was able to stabilize and positively polarize the surface of AgNPs, resulting in the stabilized and high performance of olefin separation.     

Electrocrystallization of Phase I, CuTCNQ (TCNQ = 7,7,8,8-Tetracyanoquinodimethane), on indium tin oxide and boron-doped diamond electrodes

The electrochemical reduction of TCNQ to TCNQ*- in acetonitrile in the presence of [Cu(MeCN)4]+ has been undertaken at boron-doped diamond (BDD) and indium tin oxide (ITO) electrodes. The nucleation and growth process at BDD is similar to that reported previously at metal electrodes. At an ITO electrode, the electrocrystallization of more strongly adhered, larger, branched, needle-shaped phase I CuTCNQ crystals is detected under potential step conditions and also when the potential is cycled over the potential range of 0.7 to -0.1 V versus Ag/AgCl (3 M KCl). Video imaging can be used at optically transparent ITO electrodes to monitor the growth stage of the very large branched crystals formed during the course of electrochemical experiments. Both in situ video imaging and ex situ X-ray diffraction and scanning electron microscopy (SEM) data are consistent with the nucleation of CuTCNQ taking place at a discrete number of preferred sites on the ITO surface. At BDD electrodes, ex situ optical images show that the preferential growth of CuTCNQ occurs at the more highly conducting boron-rich areas of the electrode, within which there are preferred sites for CuTCNQ formation.     

1,2,5-Triphenylpyrrole Derivatives with Dual Intense Photoluminescence in Both Solution and the Solid State: Solvatochromism and Polymorphic Luminescence Properties

Five organic luminophores, 1,2,5-triphenylpyrrole (TPP) derivatives 3 a – e bearing electron-withdrawing or electron-donating groups, have been synthesized by Pd-catalyzed Suzuki coupling of 1-phenyl-2,5-di(4′-bromophenyl)pyrrole and para-substituted phenylboronic acid derivatives. They possess good thermal stabilities with high decomposition temperatures above 310 °C. Investigation of the photophysical properties of the luminogens 3 a – e indicated that they exhibited dual intense photoluminescence in both solution and the solid state due to their twisted conformations, and their fluorescence quantum yields (Φ_F) were determined as 68.7–94.9 % in THF solution and 19.1–52.0 % in solid powder form. Compounds 3 a – c bearing electron-accepting groups exhibited remarkable solvatochromism with large Stokes shifts, attributable to their D-π-A structure and intramolecular charge-transfer effect. In particular, 3 a , bearing aldehyde groups, displayed an obvious red-shift of the emission band from 445 to 564 nm with increasing solvent polarity. However, no obvious solvatochromic behavior was observed for compounds 3 d , e bearing electron-donating groups. The luminophore 3 a exhibited polymorphic luminescence properties and crystallization-induced emission enhancement.     

Reactions of hexamethyldilead with 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetracyanoethylene (TCNE)

Hexamethyldilead reacts with TCNQ to give Pb(TCNQ)₂ and tetramethyllead and with TCNE to give Pb(TCNE).     

High pressure Raman studies of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and CuTCNQ

The high-pressure Raman studies of 7,7,8,8-tetracyanoquinodimethane (TCNQ) single crystals and polycrystalline CuTCNQ are presented in this paper. TCNQ shows a phase transition at 22 kbar, a pressure higher than reported earlier. CuTCNQ undergoes a first order phase transition at 30 kbar, which is characterized by the abrupt disappearance of all the Raman bands.     

7,7,8,8—四氰基对苯醌二甲烷的光伏—气敏特性

用表面光电压谱技术研究了7,7,8,8-四氰基对苯醌二甲烷多晶的光伏-气敏特性。结果表明,在较高真空度条件下,该化合物有两类不同的表面光电压响应峰,分别位于390 nm(P_1)和480 nm(P_2)。探针气体吸附证明,P_1表现出较强的受体性,而P_2则显示出给体性质。给体性分子与该化合物的∏键轨道作用,而受体分子与其C≡N端基作用。     

Conducting and insulating salts of phosphiniminium cations with 7,7,8,8-tetracyano-p-quinodimethane (TCNQ)

A new series of cation-TCNQ salts is described: phosphiniminium cations (1) and (2) form 1:2 salts with TCNQ that are organic conductors (σ_rt 0.05–0.15 S cm⁻¹) whereas cations (3) and (4) form insulating 1:1 salts; variable temperature conductivity, magnetic susceptibility and FTir data are described.     

Synthesis,Crystal Structures,and Properties of 6,12‐Diaryl‐Substituted Indeno[1,2‐b]fluorenes

Fused polycyclic indeno[1,2‐b]fluorene derivatives with aryl substituents at the 6,12‐positions have been prepared as a potential antiaromatic 20π electronic system. They showed strong absorptions in the visible region and amphoteric redox properties. The quinoid‐type molecular structures were revealed by X‐ray crystal‐structure analysis, which indicated that the bond lengths of the quinoid unit depend on the aryl substituents. Whereas nucleus‐independent chemical shift NICS(1) calculations indicate the antiaromatic nature of the s‐indacene core, they have higher stability than substituted acene derivatives. The derivatives with difluorophenyl or anthryl groups were stable in solution. Vapor‐deposited thin films showed ambipolar carrier transportation in the field‐effect transistor devices.     

Structural Elucidation of Selective Solvatochromism in a Responsive-at-Metal Cyclometalated Platinum(II) Complex

We report the synthesis, characterization, and spectroscopic investigations of a new responsive-at-metal cyclometalated platinum(II) complex. With mild chemical oxidants and reductants, it was possible to obtain the same complex in three different oxidation states and each of these complexes was structurally characterized by single-crystal X-ray diffraction. We discovered that the platinum(II) complex displays strong solvatochromism in the solid state, which can be attributed to modulation of Pt⋅⋅⋅Pt interactions that results in switching between optical and photoluminescent states. Incorporating responsive-at-metal species as dynamic components in nanostructured materials might facilitate response amplification, sensing, actuation, or self-healing processes.     

Spectrophotometric determination of some antihistaminic drugs using 7,7,8,8-tetracyanoquinodimethane (TCNQ)

A simple and sensitive spectrophotometric method is suggested for analysis of 3 antihistaminic drugs, acrivastine (I), mequitazine (II), and dimethindene maleate (III). The method is based on reaction of the drugs with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in acetonitrile to form highly stable colored products that are measured at 750, 766, and 844 nm for I and II, and 480 and 618 nm for III. Beer's law is obeyed in the ranges of 5-60 microg/mL for 1, 5-50 microg/mL for II, and 10-70 microg/mL for III. The optimum assay conditions and their applicability to the determination of the cited drugs in pharmaceutical formulations are described. The method is statistically analyzed as compared with the European Pharmacopoeia (2001) method for the analysis of dimethindene maleate and reference methods for acrivastine and mequitazine drugs revealing good accuracy and precision.