Home About us Contact
|
Home About us Contact | ||
|
|
||
Two-Photon Absorption Properties (two-photon + absorption_property)
Selected AbstractsStar-Shaped D-,-A Molecules Containing a 2,4,6-Tri(thiophen-2-yl)-1,3,5-triazine Unit: Synthesis and Two-Photon Absorption PropertiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2009Li Zou Abstract A series of new star-shaped donor-,-acceptor (D-,-A) molecules containing the 2,4,6-tri(thiophen-2-yl)-1,3,5-triazine unit were synthesized and characterized. The 1,3,5-triazine group, as a strong electron-accepting center, is connected to three electron-donating end groups through ,-conjugated bridges. As a result of the coexistence of the electron acceptor and donor, these compounds show reversible or quasireversible redox behavior. Through changing the peripheral end group the optical properties can be modified. All compounds exhibit two-photon absorption activity in the range of 720,880 nm and show large two-photon absorption cross sections that are closely related to the intramolecular charge transfer and ,-conjugated length of the molecule.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Vinyl-Pyridinium Triphenylamines: Novel Far-Red Emitters with High Photostability and Two-Photon Absorption Properties for Staining DNACHEMBIOCHEM, Issue 4 2007Clémence Allain Dr. Abstract A series of mono-, bis- and trisvinyl-pyridinium triphenylamines (TP-py) has been synthesised and evaluated for its one- and two-photon absorption (2PA) induced-fluorescence properties under biological conditions. Interestingly, these compounds are only weakly fluorescent in water, whereas their fluorescence emissions are strongly restored (exaltation factors of 20,100) upon binding to double-stranded DNA. Additional measurements in glycerol indicate that the fluorescence increases are the result of immobilisation of the dyes in the DNA matrix, which inhibits rotational de-excitation modes. This particular feature is especially remarkable in the case of the bis and tris derivatives (TP-2,py, TP-3,py), which each display a high affinity (Kd ,,M) for dsDNA. TPIF measurements have shown that TP-2,py and TP-3,py each have a large 2PA cross section (, up to 700 GM) both in glycerol and in the presence of DNA, which ranks them amongst the best 2PA biological fluorophores. Finally, one- and two-photon confocal imaging in cells revealed that these compounds perform red staining (,em=660,680 nm) of nuclear DNA with excellent contrast. The remarkable optical properties of the TP-py series, combined with their high photostability and their easy synthetic access, make these compounds extremely attractive for use in confocal and 2PA microscopy. [source] Enhanced Two-Photon Absorption of Organic Chromophores: Theoretical and Experimental Assessments,ADVANCED MATERIALS, Issue 24 2008Francesca Terenziani Abstract Functional organic materials with enhanced two-photon absorption lead to new technologies in the fields of chemistry, biology, and photonics. In this article we review experimental and theoretical methodologies allowing detailed investigation and analysis of two-photon absorption properties of organic chromophores. This includes femtosecond two-photon excited fluorescence experimental setups and quantum-chemical methodologies based on time-dependent density functional theory. We thoroughly analyze physical phenomena and trends leading to large two-photon absorption responses of a few series of model chromophores focusing on the effects of symmetric and asymmetric donor/acceptor substitution and branching. [source] 3,5-Bis{3-[4-(dimethylamino)phenyl]prop-2-enylidene}-1-methyl-4-piperidone and 3,5-bis[3-(4-methoxyphenyl)prop-2-enylidene]-1-methyl-4-piperidone: potential biophotonic materialsACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2008Vladimir N. Nesterov The structures of the title compounds, C28H33N3O, (I), and C26H27NO3, (II), together with their two-photon absorption properties and fluorescence activities are reported. Molecules of (II) reside on crystallographic mirror planes containing the piperidone C=O group and N -methyl H atoms. Because of the conjugation between the donor and acceptor parts, the central heterocycle in both (I) and (II) exhibits a flattened boat conformation, with deviations of the N atom and the opposite C atom from the planar fragment. The dihedral angles between the coplanar heterocyclic atoms and terminal C6 rings are less than 20° in both (I) and (II). In (I), the N -methyl group of the ring occupies an equatorial position, but in (II) it is positioned in an axial site. In the crystal structure of (I), weak intermolecular C,H...,(arene) and C,H...O steric contacts link the molecules along the a axis. In the crystal structure of (II), molecules form stacks along the b axis. [source] | ||||||||||