19900-52-8Relevant academic research and scientific papers
New cyanopyridine based conjugative polymers as blue emitters: Synthesis, photophysical, theoretical and electroluminescence studies
Pilicode, Naveenchandra,K M, Nimith,M N, Satyanarayan,Adhikari, Airody Vasudeva
, p. 6 - 15 (2018/06/19)
Herein, we report the design of three new blue light emitting conjugated polymers (Th-Py-1, Th-Py-2 and Th-Py-3), carrying cyanopyridine ring as a strong electron accepting unit and thiophene as well as phenylene vinylene scaffolds with different substituents, as electron donating moieties. The newly designed monomers/polymers were synthesized using well-known synthetic protocols such as cyclocondensation, O-alkylation, Suzuki cross coupling, Wittig and Knoevenagel reactions. They were well-characterized by spectral, thermal, photophysical, electrochemical and gel permeation chromatography (GPC) techniques. Further, they were subjected to theoretical studies using DFT simulations, performed at B3LYP/TZVP level using Turbomole 7.2 V software package. The new polymers were tested in PLED devices (ITO/PEDOT: PSS/Polymer/Al) as emissive materials. Optical studies revealed that, all the polymers displayed light absorption in the range of 377–397 nm and blue light emission in the order of 432–482 nm, respectively. Further, their band-gaps were calculated to be in the order of 2.55–2.64 eV using both optical and electrochemical data. Furthermore, the TGA study indicated that, they possess good thermal stability with onset decomposition temperature, greater than 300 ?C under nitrogen atmosphere. Interestingly, use of these polymers in new PLEDs as emissive layers, has shown improved performance when compared to previously reported polymers in similar type of devices. They show blue light emission with a low threshold voltage of 3.5–3.9 V, affirming an efficient electron injection in the diodes.
Tritium-labeled (E,E)-2,5-bis(4′-hydroxy-3′-carboxystyryl)benzene as a probe for β-amyloid fibrils
Matveev, Sergey V.,Kwiatkowski, Stefan,Sviripa, Vitaliy M.,Fazio, Robert C.,Watt, David S.,Levine, Harry
supporting information, p. 5534 - 5536 (2015/01/08)
Accumulation of Aβ in the brains of Alzheimer disease (AD) patients reflects an imbalance between Aβ production and clearance from their brains. Alternative cleavage of amyloid precursor protein (APP) by processing proteases generates soluble APP fragments including the neurotoxic amyloid Aβ40 and Aβ42 peptides that assemble into fibrils and form plaques. Plaque-buildup occurs over an extended time-frame, and the early detection and modulation of plaque formation are areas of active research. Radiolabeled probes for the detection of amyloid plaques and fibrils in living subjects are important for noninvasive evaluation of AD diagnosis, progression, and differentiation of AD from other neurodegenerative diseases and age-related cognitive decline. Tritium-labeled (E,E)-1-[3H]-2,5-bis(4′-hydroxy-3′-carbomethoxystyryl)benzene possesses an improved level of chemical stability relative to a previously reported radioiodinated analog for radiometric quantification of Aβ plaque and tau pathology in brain tissue and in vitro studies with synthetic Aβ and tau fibrils.
X-Ray structure determinations of bromo and/or bromomethylsubstituted benzenes: C-H···Br, C-Br···Br, and C-Br···p interactions
Jones, Peter G.,Kus, Piotr,Dix, Ina
, p. 1273 - 1281 (2013/02/23)
The structures of seven benzene derivatives [1,2,3-tri(bromomethyl)benzene, (1); 3,5-di(bromomethyl)bromobenzene, (2); 2,5-di(bromomethyl)bromobenzene, (3); 4-(bromomethyl)-2,5-dibromotoluene, (4); 4-(bromomethyl)bromobenzene, (5); 2,3-di(bromomethyl)bromobenzene, (6) and (bromomethyl)-p-dibromobenzene, (7)] with bromo and bromomethyl (and in one case methyl) substituents are presented and analysed in terms of Br···Br interactions up to 4.0 A , supported by hydrogen bonds H···Br. Some interactions of the type Br···π and π·· · π are encountered and play a subordinate role in the packing. Despite the close chemical similarity of the compounds, some of which are isomers with permuted substituent positions, the packing motifs are highly variable. Compounds 2-5 are based on layer structures with Brn (n=3, 4) and/or mixed Br/C rings. Compounds 1, 6 and 7 display three-dimensional packings of differing complexity, but with interpretable substructures; 1 can be analysed in terms of ribbons of linked Br3 and Br4 rings; 6 displays chains of linked Br3 triangles; 7 consists of ribbons of linked Br4 quadrilaterals.
Thermodynamic forecasting of mechanically interlocked switches
Olson, Mark A.,Braunschweig, Adam B.,Ikeda, Taichi,Fang, Lei,Trabolsi, Ali,Slawin, Alexandra M. Z.,Khan, Saeed I.,Stoddart, J. Fraser
scheme or table, p. 4391 - 4405 (2009/12/25)
Mechanically interlocked molecular (MIM) switches in the form of bistable [2]rotaxanes and [2]catenanes have proven to be - when incorporated in molecular electronic devices (MEDs) and in nanoelectromechanical systems (NEMS) - a realistic and viable alternative to the silicon chip density challenge. Structural modifications and chemical environment can have a large impact on the relaxation thermodynamics of the molecular motions, such as translation and circumrotation in bistable rotaxanes and catenanes responsible for the operation of devices based on MIMs. The effects of structural modifications on the difference in free energy (ΔGo) for the equilibrium processes in switchable MIMs can be predicted by considering, firstly, the interactions present in their precursor pseudorotaxanes. By employing isothermal titration microcalorimetry (ITC) to investigate the thermodynamic parameters governing pseudorotaxane formation for a series of monosubstituted, acceptor host cyclophanes with various donor guests, in conjunction with X-ray crystallographic data, an obvious link between the noncovalent bonding interactions in pseudorotaxanes and MIMs that survive following the formation of the mechanical bond can be identified. It follows that the changes (ΔΔGo values) in the difference of free energy during the formation of different pseudorotaxanes can subsequently be extrapolated to predict ΔGo values for the thermodynamics associated with switching in analogous MIM switches, employing the same donor-acceptor recognition components. In this manner, a systematic and predictive thermodynamic approach to designing and tuning switchable MIMs and MIM-based materials has been established. Additionally, these thermodynamic relationships are reminiscent of the long forgotten concept of the 'parachor' as a molecular descriptor with respect to the additivity of physical properties in chemical systems dealing specifically with quantitative structure property-activity relationships (QSPR/QSAR).
Preparation and spectroscopic study of 13-substituted 2,11- dithiahexahydro[3.3]paracyclophanes
Lin, Shaw-Tao,Yang, Ya-Chen,Lin, Shu-Farn,Hwang, Lih-Jiun
, p. 708 - 711 (2007/10/03)
A series of 13-substituted 2,11-dithiahexahydro[3.3]paracyclophanes each containing a substituent on the benzene ring were prepared for 1H NMR and X-ray diffraction analyses. The benzene ring and the cyclohexane ring demonstrate shielding of th
Functionalized heptahelicene bidentate ligands and chiral building blocks
Gingras, Marc,Collet, Christine
, p. 2337 - 2341 (2007/10/03)
Syntheses of functionalized heptahelicenes 11-13 disubstituted at positions 3 and 16 by hydroxymethyl or bromomethyl functions are described as a new series of bidentate ligands or chiral building blocks. Those functions are flexible enough and properly p
Polymer electroluminescent device
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, (2008/06/13)
A polymer electroluminescent device (1) comprises an electroluminescent layer (7) of a poly(1,4-phenylenevinylene) having aryl-1,4-phenylene units, where the aryl group is a phenyl, naphthyl or biphenylyl group. Using such a poly(1,4-phenylenevinylene) has the effect that the light emitted by the polymer electroluminescent device has no or at least a reduced tendency to change color when driven the device is and/or kept at an elevated ambient temperature of, for example, 70 °C. The poly(1,4-phenylenevinylene)s having aryl-1,4-phenylene units are prepared using aryl-bishalomethylbenzenes as an intermediate compound.
Synthesis and properties of optically active helical metallocene oligomers
Katz, Thomas J.,Sudhakar, Anantha,Teasley, Mark F.,Gilbert, Adam M.,Geiger, William E.,Robben, Matthew P.,Wuensch, Martin,Ward, Michael D.
, p. 3182 - 3198 (2007/10/02)
Syntheses are described for optically active oligomers 9 and 27. The steps required have three essential features. (1)A bromine directs a photocyclization, blocking both the position it occupies and the one adjacent. (2) An acid scavenger (propylene oxide
DIRECTIVE EFFECT OF BROMINE ON STILBENE PHOTOCYCLIZATIONS. AN IMPROVED SYNTHESIS OF HELICENE
Sudhakar, Anantha,Katz, Thomas J.
, p. 2231 - 2234 (2007/10/02)
Bromine atoms direct photocyclizations away both from positions they occupy and from those adjacent, providing previously unavailable selectivities in syntheses of helicenes.
