Synthesis,physical properties,and structure of TIPS-difuranoacenes

The synthesis, physical properties, and structure of triisopropylsilylethynyltetracenodifuran (2) and pentacenodifuran (3) derivatives were reported. There showed high stability in solution in the dark, yet decomposed under light. Single crystal of pentacenodifuran was analyzed by X-ray diffraction analysis, and showed one dimensional packing array along the c-axis. The molecules were stacked with a 3.30 Å interlayer distance. The crystals exhibited a high thermal stability under an ambient condition.     

Anthracene based organic dipolar compounds for sensitized solar cells

Organic dyes that consist of an anthracene moiety between a triphenylamine donor group and a cyanoacrylic acid acceptor group displayed remarkable solar-to-energy conversion efficiency in dye-sensitized solar cells. The planar geometry of anthracene and its bulky substituents helped the dyes to form a high quality monolayer on the surface of TiO₂. A typical device made with the dye AN-Bu displayed a maximal photon-to-current conversion efficiency (IPCE) 65% in the region of 350–510 nm, a short-circuit photocurrent density (J_sc) 12.78 mA cm⁻², an open-circuit photovoltage (V_oc) 0.73 V, and a fill factor (FF) 0.67, corresponding to an overall conversion efficiency 6.23%. In an experiment of using deoxycholic acid (DCA) as a co-absorbent, the values of V_oc stayed in a similar range, yet the values of J_sc were reduced in ca. 11% due to a decrease of loading amounts. This result indicated that the quality of the dye films cannot be further improved by the adding of DCA. The photophysical properties were analyzed with the aid of a time-dependent density functional theory (TDDFT) model with the B3LYP functional.     

Development of Reasonably Stable Chitosan Based Proton Exchange Membranes for a Glucose Oxidase Based Enzymatic Biofuel Cell

Chitosan based reasonably stable membranes were prepared as polymeric electrolyte and separator for enzymatic fuel cell applications. Glucose oxidase (GOx) bioanode centered biofuel cell with the developed chitosan membranes performed much better in stability with high current densities than that of the biofuel cell utilizing a 125 μ‐thick perfluorosulfonic acid‐type membrane (i. e. Nafion® 115). Proposed chitosan membrane structural stability was enhanced by employing cellulosic support materials and chemical crosslinking. The effects of pH, buffer type, buffer concentration, temperature on the manufactured chitosan membranes along with the biofuel cell system were investigated. The biofuel cell operation parameters were optimized for the current density and stability aspects and more than 3 mA cm^?2 current density was acquired from the cell at optimum conditions. Operational half‐life of the chitosan membrane was found as higher than the half‐life of the GOx immobilized bioanode. Therefore, this result indicates that chitosan membrane structural stability was not a limiting issue for the biofuel cell lifespan.     

A FLUOROGENIC ACTINOMETER FOR NUCLEIC ACID PHOTOCHEMISTRY UTILIZING 1-DEAZAPURINE N(3)-OXIDES

A convenient and very sensitive actinometery system for UV radiation with wavelengths in the range250–310 nm is described, which is based on the fluorogenic photorearrangement of 1-deazapurine N(3)-oxide. The product, 1-deazapruin-2-one, can be estimated fluoremetrically in the presence of the N-oxide of 1-deazapurine and 1-methyl-1-deazapurine fail in the range 0.13-0.15 and do not vary significantly with wavelength. There is potential for using 1-deazupurine N(3)-oxides as UV-photoactivable fluorophores.     

Synthesis,Spectroscopic Studies and Crystal Structure of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-bis((thiophene-2-carboxamido)propyl)piperazine

Abstract  A new multidentate ligand N,N′-bis((thiophene-2-carboxamide)propyl)piperazine has been synthesized from the reaction of thiophene-2-carbonylchloride and 1,4-bis(3-aminopropyl)piperazine. The title compound has been characterized by elemental analysis, FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. The crystal structure of the title compound (C₂₀H₃₀N₄O₂S₂Cl₂) has also been determined by X-ray analysis. The title compound crystallize in the monoclinic space group P2₁/c with a = 9.768(1), b = 12.895(1), c = 10.083(1) ?, β = 115.12(1)°, V = 1149.9(2) ?³, D _x = 1.425 g cm⁻³ and Z = 2. The crystal structure was solved by direct methods and refined by full-matrix least squares to a find R = 0.039 [I > 2σ (I)] for 2,786 observed reflections. Graphical Abstract  The (N,N’–bis((thiophene-2- carboxamido)propyl)piperazine) molecule has been synthesized and its molecule structure has been investigated by using , FT-IR, 13C NMR and 1H-NMR spectroscopic and crystallographic techniques.

1,7-Dinitroperylene bisimides: facile synthesis and characterization as n-type organic semiconductors

1,7-Dinitroperylene bisimides (1a-1b) and 1-nitroperylene bisimides (2a-2b) were synthesized under mild condition in high yields, and were characterized by FT-IR, ¹H NMR, UV-vis, HRMS spectra, cyclic voltammetry, and thermogravimetric analyses. These compounds are stable up to 260 °C according to thermogravimetric analyses. They undergo two quasi-reversible one-electron reductions in THF at modest potentials. The nitro functionalities provide stability of n-type charge carriers by lowering the LUMO to resist ambient oxidation.     

Impedance‐based viscoelastic flow cytometry

Elastic nature of the viscoelastic fluids induces lateral migration of particles into a single streamline and can be used by microfluidic based flow cytometry devices. In this study, we investigated focusing efficiency of polyethylene oxide based viscoelastic solutions at varying ionic concentration to demonstrate their use in impedimetric particle characterization systems. Rheological properties of the viscoelastic fluid and particle focusing performance are not affected by ionic concentration. We investigated the viscoelastic focusing dynamics using polystyrene (PS) beads and human red blood cells (RBCs) suspended in the viscoelastic fluid. Elasto‐inertial focusing of PS beads was achieved with the combination of inertial and viscoelastic effects. RBCs were aligned along the channel centerline in parachute shape which yielded consistent impedimetric signals. We compared our impedance‐based microfluidic flow cytometry results for RBCs and PS beads by analyzing particle transit time and peak amplitude at varying viscoelastic focusing conditions obtained at different flow rates. We showed that single orientation, single train focusing of nonspherical RBCs can be achieved with polyethylene oxide based viscoelastic solution that has been shown to be a good candidate as a carrier fluid for impedance cytometry.     

Design and numerical analysis of a gold-coated photonic crystal fiber based refractive index sensor

Optical and Quantum Electronics - Optical sensors are very attractive in chemical and bio-chemical applications due to some unique characteristics, such as immunity to electromagnetic interference...     

Heptacene: Synthesis and Its Hole-Transfer Property in Stable Thin Films

Heptacene ( 1 ) has been produced via a monoketone precursor, 2 , which was prepared from 1,2,4,5-tetrabromobenzene in nine steps in a total yield of 10 %. Compound 2 was converted to 1 quantitatively by heating at 202 °C. Heptacene exhibited high thermal stability in the solid state without any observable change over two months. To investigate the potential value of 1 as a material for p-type organic field-effect transistors (OFETs), top-contact OFET devices were fabricated by vacuum deposition of 1 onto a hexamethyldisilazane (HMDS)/SiO₂/Si substrate. The best hole mobility performance was 2.2 cm² V⁻¹ s⁻¹. This is the first report of stable heptacene being used in an effective device and examined for its charge carrier properties.