Search results for "absorption"

Photoelectrical properties of indandione fragment containing azobenzene compounds

2014

Organic materials are becoming more popular due to their potential application in electronics. Low molecular weight materials possible produce from solution are in special consideration. It gives the possibility to avoid both thermal evaporation in vacuum, and use of polymers in thin film preparation process. Indandione fragment containing azobenzene compounds are one of such materials. These compounds are good candidates for use in design of novel molecular electronic devices due to their possibility to form amorphous structure from solution thus allowing developing flexible, small size systems with low production costs. In this work three indandione fragment containing azobenzene compound…

1986

Preparation and mechanical characterization of fibres from a new copoly(ether-ester-amide) are reported. The mechanical characteristics are slightly lower than those of polyamide 6, but satisfactory for textile use, and the fibres have larger moisture absorption. This gives rise to more comfortable fibres preventing the accumulation of electrostatic charges. Die Herstellung und mechanische Charakterisierung von Fasern aus einem neuen Copoly(ether-ester-amid) werden beschrieben. Die mechanischen Eigenschaften sind etwas schlechter als die von Polyamid 6, aber ausreichend fur textile Anwendungen. Die Fasern weisen eine grosere Feuchtigkeitsabsorption auf. Dies fuhrt zu einem angenehmeren Verh…

Synthesis, optical, and thermal properties of glassy trityl group containing luminescent derivatives of 2-tert-butyl-6-methyl-4H-pyran-4-one

2012

In this work we present simple preparation of original trityl group containing glassy luminescent 6-styryl substituted derivatives of 2-(2-tert-butyl-4H-pyran-4-ylidene)malononitrile (DWK-1TB), 2-(2-tert-butyl-4H-pyran-4-ylidene)-2- ethyl-2-cyanoacetate (KWK-1TB), 2-(2-tert-butyl-4H-pyran-4-ylidene)-1H-indene-1,3(2H)-dione (ZWK-1TB) and 5-(2-tert-butyl-4H-pyran-4-ylidene)pyrimidine-2,4,6(1H,3H,5H)-trione (JWK-1TB). Their optical properties have been investigated. The absorption maxima of synthesized glasses is in region from 425 nm to 515 nm and emission maxima is from 470 nm to 625 nm in solution of dichloromethane. But absorption maxima of their solid films is from 425 nm to 500 nm and em…

Polymere Charge-transfer-Komplexe auf der Basis von Polyvinylalkoholacetalen

1978

Poly[2-(1-naphthyl)-1,3-dioxan-4,6-diylmethylene] (3), poly[2-(2-naphthyl)-1,3-dioxan-4,6-diylmethylene] (5), 1-naphthalenecarbaldehydetrimethyleneacetal (7) and 2-naphthalenecarbaldehydetrimethyleneacetal (8) were synthesized and characterized by UV- and fluorescencespectroscopy. In addition triplet-triplet absorption maxima and triplet-lifetimes were determined by flash technique. The naphthalene derivates were found to act as donors in the charge-transfer complex formation with such electron acceptors as tetracyanoethylene, 2,5-cyclohexadien-1,4-diylidenedimalonodinitrile and 2,4,5,7-tetranitro-9-fluorenone. The equilibrium constants of the charge-transfer complexes were determined spect…

Synthesis and Characterization of Extended Bis(terpyridine)ruthenium Amino Acids

2009

(Oligopyridine)ruthenium(II) complexes have been widely used in dye sensitized solar cells and other sophisticated optical devices due to their outstanding photophysical properties and their chemical stability. Herein, we describe the longitudinal extension of our previously reported bis(terpyridine)ruthenium(II) amino acid [Ru(tpy–NH2)(tpy–COOH)]2+ (tpy = 4′-substituted 2,2′:6′,2″-terpyridine) by insertion of para-phenylene spacers –C6H4– between the terpyridine and the functional groups. The influence of the para-phenylene spacer on the absorption and emission properties is investigated using UV/Vis absorption and emission spectroscopy and is discussed within a qualitative molecular orbit…

Characterization of intestinal absorption of C -glycoside flavonoid vicenin-2 from Lychnophora ericoides leafs in rats by nonlinear mixed effects mod…

2015

Vicenin-2 (apigenin-6,8-di-C-β-d-glucopyranoside) is present in hydroalcoholic extracts of the Brazilian species Lychnophora ericoides Mart., Asteraceae, leaves, and the biological effects of this compound have been demonstrated including anti-inflammatory, antioxidant and anti-tumor effects in rat models. Given the potential of this compound as a pharmacological agent, the aims of this investigation were to evaluate the extent of intestinal absorption of vicenin-2, and to determine the intestinal permeation profile using an in situ single-pass intestinal perfusion technique. A validated HPLC–UV method was applied to measure the amount of unabsorbed vicenin-2 in the gut after an oral admini…

Structural characterization of U(VI) surface complexes on kaolinite in the presence of humic acid using EXAFS spectroscopy.

2007

To determine the influence of humic acid (HA), pH, and presence of atmospheric CO2 on the sorption of U(VI) onto kaolinite, the structure of the surface complexes was studied by U L III-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. The best fits to the experimental EXAFS data were obtained by including two uranium coordination shells with two axial (O ax) and five equatorial (O eq) oxygen atoms at 1.77+/-0.02 and 2.34+/-0.02 A, respectively, and two coordination shells with one Al/Si atom each at 3.1 and 3.3 A. As in the case of the binary system U(VI)-kaolinite, uranium forms inner-sphere surface complexes by edge sharing with aluminum octahedra and/or silicon tetrahe…

Optical Absorption of Zinc Selenide Doped with Cobalt (Zn1-xCoxSe) under Hydrostatic Pressure

2000

Optical absorption of the diluted magnetic semiconductor Zn 1-x Co x Se (x = 0.02) has been measured at room temperature under hydrostatic pressure up to 14 GPa in a membrane diamond-anvil cell. We found two absorption features: (i) an absorption structure in the energy range 1.5 to 1.8 eV, with a negligible pressure shift (i.e. (0.45 ± 0.05) meV/GPa) which we have identified as the Co 2+ (3d 7 ) internal transition 4 A 2 (F) → 4 T 1 (P) and (ii) an onset in the energy range 2 to 2.7 eV which redshifts with pressure (dE/dP = (-8.1 ± 0.6) meV/GPa). We have attributed such absorption edge to charge transfer between the ZnSe valence band and the Co 2+ (3d 7 ) levels. On the assumption that tho…

Absorption spectrum of the f(A1g) ← X(Eg), a(F2g) electronic transition of OsF6

1997

Abstract The absorption spectrum of the visible band of OsF 6 has been recorded using a commercial spectrophotometer. The first vibronic assignments for this band have been realized using the analogy with the d ← X transition of IrF 6 . Some vibronic parameter values are derived.

Erweiterte Konjugation in unsymmetrischen Stilbenylsquarainen

1998

Extended Conjugation in Stilbenylsquaraines Unsymmetrical 1-aryl-3-stilbenylsquaraines 2a–e and 1,3-bis(stilbenyl)squaraines 3a–c were prepared by CC coupling reactions of the corresponding substituted arenes with derivatives of squaric acid (Schemes 2 and 3). Dialkylamino and alkoxy groups enhance the solubility of these dyes and enlarge the intramolecular charge transfer of these donor–acceptor–donor systems. The extended conjugation of the stilbene units – in comparison with arene building blocks – leads to significant bathochromic shifts in the Vis/NIR absorption spectra.