298 research outputs found
The synthesis of a symmetrically substituted α-octa(isopentoxy)anthralocyanine
α-Octa(isopentoxy)anthralocyanine has been synthesized and is found to have an unprecedented low-energy Q-band absorption and a low first oxidation potential
Molecular First Hyperpolarizabilities of a New Class of Asymmetric Squaraine Dyes
The molecular first hyperpolarizabilities (β) of a series of asymmetric squaraine dyes have been measured by electric-field-induced second harmonic generation; the dyes have negative β-values whose magnitudes are comparable to 4-N,N-dimethylamino-4′-nitrostilbene (DANS)
The First Molecular Electronic Hyperpolarizabilities of Highly Polarizable Organic Molecules: 2,6-Di-tert-butylindoanilines
The first molecular hyperpolarizabilities (β) of a series of 2,6-di-tert-butylindoanilines, measured by electric-field-induced second harmonic generation are somewhat more sensitive to donor strength than was found for analogously substituted nitrostilbenes, and dimethylindoaniline has a β roughly twice that of its 2,6 di-tert-butylated analogue, measured in chloroform; solvatochromic measurements on the former compound suggest that this decrease in hyperpolarizability is consistent with a bound-solvent effect
The Effect of varying Ground-state Aromaticity on the First Molecular Electronic Hyperpolarizabilites of Organic Donor-Acceptor Molecules
A series of compounds of the form 4-dimethylaminophenyl–polyene–acceptor, where the polyene ranges from nothing to all-trans-1,3,5-hexatriene and the acceptor is 2-nitrovinyl, formyl, or 2,2-dicyanovinyl has been prepared and their β values measured by solution electric-field-induced second-harmonic generation; these molecules, which lose only one aromatic resonance upon charge-transfer excitation, show enhanced β compared to bi-aromatic molecules with the same substitution and total conjugation length, such as 4-dimethylamino-4′-nitrostilbene (DANS), a well-known benchmark for high β organic molecules
Synthesis and First Hyperpolarizabilities of Acceptor-substituted β-apo-8’-Carotenal Derived Compounds
The synthesis and second-order nonlinear optical properties of acceptor-substituted biologically derived β-apo-8′-carotenal compounds are reported; electric field-induced second harmonic generation (EFISH) measurements give values of β(0) which are 2–6 times greater than for 4-N,N-dimethylamino-4′-nitrostilbene (DANS)
Development of electro-optic polymers for high-voltage instrument transformers
This paper describes some poled electrooptic bulk polymers (EOP) of the guest/host type having a cured epoxy resin as the host. The electrooptic polymers of typical dimensions 13 X 13 X 3 mm are characterized with respect to application as Pockels materials in an optical high voltage sensor. The electrooptic coefficients obtained here are of the same order of magnitude as those which are required for high voltage applications. An optical sensor based on disperse red 1 dye and an epoxy polymer is developed. It is able to measure voltages up to 10 kV AC. It is shown that bulk EOP can be produced with relatively large physical dimensions comparable to commercially available Pockels crystals. A technique is described which compensates for the inevitable intrinsic birefringence built into most bulk polymers. The epoxy based EOP shows high orientational stability, even when compared with a polysulfone based EOP having a higher glass transition temperature
The one-electron oxidation product of a metallocenyl-terminated cyanine
The 1-(2,3,4,5,1',2',3',4'-octamethylferrocen-1-yl)-3-(ruthenocenyl)allylium cation readily undergoes one-electron oxidation to a dication in which an octamethylferrocenium moiety is bridged by a vinylene group to a [(η^6-fulvene)(η^5-cyclopentadienyl)ruthenium]+ moiety. In the title compound, 1-(2,3,4,5,1',2',3',4'-octamethylferrocen-1-yl)-3-(ruthenocenylidene)prop-1-enium(2+) bis(tetrafluoroborate), [FeRu(C_5H_5)(C_9H_(13))(C_(17)H_(19))](BF_4)_2, the C-C bond lengths in the bridge (average for two independent molecules) are, starting from the ipso octamethylferrocenium carbon and ending at the exo carbon of the coordinated fulvene, 1.455 (6), 1.344 (3) and 1.449 (8) Å, indicating a localized electronic structure
Unsymmetrical squaraines for nonlinear optical materials
Compositions for use in non-linear optical devices. The compositions have first molecular electronic hyperpolarizability (.beta.) either positive or negative in sign and therefore display second order non-linear optical properties when incorporated into non-linear optical devices
The dependence of the molecular first hyperpolarizabilities of merocyanines on ground-state polarization and length
We report here the dipole moment (µ) and first hyperpolarizability (β) determined by electric field-induced second harmonic generation, for several merocyanine dyes containing an 1,3,3-trimethylindoline heterocycle as a ‘donor’ in which the ‘acceptor’ end of the molecule and the polyene bridge length was systematically varied; dyes with hexamethine bridges gave positive β, while that with a dimethine bridge gave a negative β value
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