Rationally Designed Phthalocyanines Having Their Main Absorption Band beyond 1000 nm

2011 ◽  
Vol 133 (49) ◽  
pp. 19642-19645 ◽  
Author(s):  
Nagao Kobayashi ◽  
Taniyuki Furuyama ◽  
Koh Satoh
Keyword(s):  
Absorption Band ◽  
Main Absorption Band

Excitation spectra of the triplet states of some model lignin compounds

1976 ◽  
Vol 29 (9) ◽  
pp. 2073 ◽  
Author(s):  
GJ Smith ◽  
IJ Miller ◽  
WH Melhuish
Keyword(s):  
Electron Spin Resonance ◽  
Low Temperature ◽  
Absorption Band ◽  
Alternative Pathway ◽  
Triplet States ◽  
Excitation Spectra ◽  
Main Band ◽  
Main Absorption Band ◽  
Spin Resonance ◽  
Energy Degradation

The triplet state excitation spectra of a number of model lignin compounds have been determined by measurements of the electron spin resonance signals associated with their triplet states in low-temperature glasses at 110 K. The optimum wavelengths for excitation of these triplet states were found to be in the tail of the main absorption band at 320-340 nm. It is postulated that excitation in the main band is inefficient in producing triplet states because of an alternative pathway for energy degradation.

scholarly journals GEOMETRICAL ISOMERS OF RETINENE

1953 ◽  
Vol 36 (3) ◽  
pp. 415-429 ◽  
Author(s):  
Ruth Hubbard ◽  
Robert I. Gregerman ◽  
George Wald
Keyword(s):  
Absorption Band ◽  
Absorption Spectra ◽  
Present Theory ◽  
Trans Configuration ◽  
Trans Isomers ◽  
Geometrical Isomers ◽  
Main Absorption Band ◽  
Antimony Chloride ◽  
Cis Isomer

Five crystalline retinenes have been isolated, which have every appearance of being cis-trans isomers of one another. They are all-trans retinene; three apparently mono-cis isomers: neoretinenes a and b and isoretinene a; and isoretinene b, an apparently di-cis isomer. The absorption spectra of these substances display the relations expected of cis-trans isomers. The main absorption band is displaced 5.5 to 7 mµ toward shorter wave lengths for each presumptive cis linkage. Some of the presumptive cis isomers also display a cis peak at 255 to 260 mµ. All five substances yield an identical blue product on mixing with antimony chloride. All of them are converted by light to what appears to be an identical mixture of stereoisomers. Heat isomerizes them very slowly; only neoretinene b exhibits large changes on heating at 70°C. for 3 hours. The various isomers have been extensively interconverted by gentle procedures, and all of them have been converted to all-trans retinene. The present theory of cis-trans isomerism in carotenoids predicts the existence of four stable isomers of retinene. Instead we seem to have five—specifically three mono-cis forms where two are expected. There is no doubt that all these substances are closely related isomers of one another. The only point in question is whether they differ in part by something other than cis-trans configuration. One possibility, as yet little supported by evidence, is that isomerization between ß- and α-ionone rings may be involved. If, however, as seems more likely, all these substances are geometrical isomers of one another, some modification is needed in the present theory of configurational relationships in this class of compounds.

scholarly journals Visual Pigments of Goldfish Cones

1974 ◽  
Vol 63 (3) ◽  
pp. 279-304 ◽  
Author(s):  
Ferenc I. Hárosi ◽  
Edward F. MacNichol
Keyword(s):  
Absorption Band ◽  
Oscillator Strength ◽  
Optical Density ◽  
Visual Pigment ◽  
Visual Pigments ◽  
Main Absorption Band ◽  
Dichroic Ratio ◽  
Outer Segments ◽  
Retinal Photoreceptors ◽  
Cone Pigments

Freshly isolated retinal photoreceptors of goldfish were studied microspectrophotometrically. Absolute absorptance spectra obtained from dark-adapted cone outer segments reaffirm the existence of three spectrally distinct cone types with absorption maxima at 455 ± 3,530 ± 3, and 625 ± 5 nm. These types were found often recognizable by gross cellular morphology. Side-illuminated cone outer segments were dichroic. The measured dichroic ratio for the main absorption band of each type was 2–3:1. Rapidly bleached cells revealed spectral and dichroic transitions in regions near 400–410, 435–455, and 350–360 nm. These photoproducts decay about fivefold as fast as the intermediates in frog rods. The spectral maxima of photoproducts, combined with other evidence, indicate that retinene2 is the chromophore of all three cone pigments. The average specific optical density for goldfish cone outer segments was found to be 0.0124 ± 0.0015/µm. The spectra of the blue-, and green-absorbing cones appeared to match porphyropsin standards with half-band width Δν = 4,832 ± 100 cm–1. The red-absorbing spectrum was found narrower, having Δν = 3,625 ± 100 cm–1. The results are consistent with the notion that visual pigment concentration within the outer segments is about the same for frog rods and goldfish cones, but that the blue-, and green-absorbing pigments possess molar extinctions of 30,000 liter/mol cm. The red-absorbing pigment was found to have extinction of 40,000 liter/mol cm, assuming invariance of oscillator strength among the three cone spectra.

scholarly journals GALLOXANTHIN, A CAROTENOID FROM THE CHICKEN RETINA

1948 ◽  
Vol 31 (5) ◽  
pp. 377-383 ◽  
Author(s):  
George Wald
Keyword(s):  
Absorption Spectrum ◽  
Absorption Band ◽  
Chromatic Aberration ◽  
Antimony Trichloride ◽  
The Other ◽  
Main Absorption Band ◽  
Deep Blue ◽  
Near Ultraviolet ◽  
Strong Adsorption ◽  
Chicken Retina

A new carotenoid has been isolated from the chicken retina for which the name galloxanthin is proposed. This substance has the properties of a hydroxy carotenoid or xanthophyll. It has not yet been crystallized. On a chromatogram of calcium carbonate it is adsorbed just below astaxanthin and above lutein. The absorption spectrum of galloxanthin lies in a region where natural carotenoids have not ordinarily been found. Its main, central absorption band falls at about 400 mµ. The position of its spectrum suggests a conjugated system of eight double bonds. This relatively short polyene structure must be reconciled with very strong adsorption affinities. With antimony trichloride, galloxanthin yields a deep blue product, possessing a main absorption band at 785 to 795 mµ, and a secondary maximum at about 710 mµ which may not be due to galloxanthin itself. Galloxanthin appears to be one of the carotenoid filter pigments associated with cone vision in the chicken. It may act as an auxiliary to the other filter pigments in differentiating colors; or its primary function may be to exclude violet and near ultraviolet radiations for which the eye has a large chromatic aberration.

scholarly journals One-step synthesis of ball-shaped metal complexes with a main absorption band in the near-IR region

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Taniyuki Furuyama ◽  
Fumika Shimasaki ◽  
Natsumi Saikawa ◽  
Hajime Maeda ◽  
Masahito Segi
Keyword(s):  
Absorption Band ◽  
Metal Ion ◽  
Rational Design ◽  
Solar Spectrum ◽  
Design Guidelines ◽  
Absorption Bands ◽  
Main Absorption Band ◽  
Near Ir ◽  
One Step ◽  
Ir Light

Abstract The design of near-IR materials is highly relevant to energy and pharmaceutical sciences due to the high proportion of near-IR irradiation in the solar spectrum and the high penetration of near-IR light in biological samples. Here, we show the one-step synthesis of hexacoordinated ruthenium and iron complexes that exhibit a main absorption band in the near-IR region. For that purpose, novel tridentate ligands were prepared by condensation of two diimines and four cyanoaryl derivatives in the presence of ruthenium and iron template ions. This method was applied to a wide variety of cyanoaryl, diimine, and metal ion combinations. The relationship between the structure and the optical and electrochemical properties in the resulting complexes was examined, and the results demonstrated that these compounds represent novel near-IR materials whose physical properties can be controlled based on rational design guidelines. The intense absorption bands in the 700–900 nm region were assigned to metal-to-ligand charge transfer (MLCT) transitions, which should allow applications in materials with triplet excited states under irradiation with near-IR light.

Reinterpretation of the main absorption band of 1,3‐butadiene

1988 ◽  
Vol 89 (3) ◽  
pp. 1255-1261 ◽  
Author(s):  
Ruth McDiarmid ◽  
Abdol‐Hakim Sheybani
Keyword(s):  
Absorption Band ◽  
Main Absorption Band

The identification value of the 2293 cm−1infrared absorption band in natural and hydrothermal synthetic emeralds

2006 ◽  
Vol 30 (1) ◽  
pp. 75-82 ◽  
Author(s):  
J.M. Duroc-Danner
Keyword(s):  
Absorption Band

First Nano-Infrared Spectroscopy and Imaging Measurements of Single Phospholipid Bilayers

2018 ◽  
Author(s):  
Adrian Cernescu ◽  
Michał Szuwarzyński ◽  
Urszula Kwolek ◽  
Karol Wolski ◽  
Paweł Wydro ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectroscopy ◽  
Absorption Band ◽  
Spectral Region ◽  
Near Field ◽  
Phospholipid Bilayers ◽  
Model Systems ◽  
Absorption Bands ◽  
Protein Complement ◽  
20 Nm

<div><div>Scattering-mode Scanning Near-Field Optical Microscopy (sSNOM) allows one to obtain absorption spectra in the mid-IR region for samples as small as 20 nm in size. This configuration has made it possible to measure FTIR spectra of the protein complement of membranes. (Amenabar 2013) We now show that mid-IR sSNOM has the sensitivity required to measure spectra of phospholipids in individual bilayers in the spectral range 800 cm<sup>-1</sup>–1400 cm<sup>-1</sup>. We have observed the main absorption bands of the dipalmitoylphosphatidylcholine headgroups in this spectral region above noise level. We have also mapped the phosphate absorption band at 1070 cm<sup>-1</sup> simultaneously with the AFM topography. We have shown that we could achieve sufficient contrast to discriminate between single and multiple phospholipid bilayers and other structures, such as liposomes. This work opens the way to further research that uses nano-IR spectroscopy to describe the biochemistry of cell membranes and model systems.</div></div><div></div>

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