Structural Studies of Bacteriorhodopsin from Halobacterium cutirubrum by Resonance Raman Spectroscopy

1974 ◽  
Vol 52 (9) ◽  
pp. 774-781 ◽  
Author(s):  
R. Mendelsohn ◽  
A. L. Verma ◽  
H. J. Bernstein ◽  
M. Kates
Keyword(s):  
Schiff Base ◽  
Resonance Raman Spectroscopy ◽  
Bathochromic Shift ◽  
Resonance Raman ◽  
Electron System ◽  
Concomitant Increase ◽  
Chemical Reagents ◽  
Membrane Bound ◽  
Resonance Raman Spectra ◽  
Pigment Absorption

Resonance Raman spectra are reported for suspensions of the membrane-bound protein "bacteriorhodopsin" isolated from Halobacterium cutirubrum. Most of the observed vibrations arise from the conjugated Schiff base of retinal in the chromophore. Excitation profiles for two C=C stretching vibrations at 1529 cm−1 and 1568 cm−1 show that the former is coupled to the 560 nm pigment absorption band, whereas the latter is coupled to a shorter wavelength transition. The 1529 cm−1 mode is shifted by ~40 cm−1 from retinylidenelysine in solution showing that the π electron system of the Schiff base is considerably perturbed by the protein. It is this interaction that is responsible for the bathochromic shift in the pigment.The addition of diethyl ether shifts λmax to 460–490 nm, and causes a decrease in the intensity at 1529 cm−1, with a concomitant increase at 1568 cm−1. The effect is reversible. Ether appears to weaken considerably the chromophore–protein interaction, making the chromophore more vulnerable to chemical reagents.

scholarly journals Short-Time Photodissociation Dynamics of 1-Chloro-2-Iodoethane From Resonance Raman Spectroscopy

1999 ◽  
Vol 19 (1-4) ◽  
pp. 71-74 ◽  
Author(s):  
Xuming Zheng ◽  
David Lee Phillips
Keyword(s):  
Raman Spectroscopy ◽  
Absorption Spectrum ◽  
Raman Spectra ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Time Dependent ◽  
Internal Excitation ◽  
Band Absorption ◽  
Resonance Raman Spectra ◽  
Short Time

We have obtained A-band absorption resonance Raman spectra of 1-chloro-2- iodoethane in cyclohexane solution. We have done preliminary time-dependent wavepacket calculations to simulate the resonance Raman intensities and absorption spectrum in order to learn more about the short-time photodissociation dynamics. We compare our preliminary results for 1-chloro-2-iodoethane with previous resonance Raman results for iodoethane and find that there appears to be more motion along non- C—I stretch modes for 1-chloro-2-iodoethane than for iodoethane. This is consistent with results of TOF photofragment spectroscopy experiments which indicate much more internal excitation of the photoproducts from 1-chloro-2-iodoethane photodissociation than the photoproducts from iodoethane photodissociation.

scholarly journals The Carbonate, Co3−·, in Solution Studied by Resonance Raman Spectroscopy

1999 ◽  
Vol 19 (1-4) ◽  
pp. 311-316 ◽  
Author(s):  
Susan M. Tavender ◽  
Steven A. Johnson ◽  
Daniel Balsom ◽  
Anthony W. Parker ◽  
Roger H. Bisby
Keyword(s):  
Amino Acids ◽  
Raman Spectroscopy ◽  
Group Theory ◽  
Free Radical ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Point Group ◽  
Biological Significance ◽  
Molecular Symmetry ◽  
Resonance Raman Spectra

The carbonate radical (Co3−·) is of biological significance acting as an intermediate in free radical-mediated damage and is capable of oxidising amino acids and proteins. In order to distinguish between the four possible structures of Co3−·, nanosecond timeresolved resonance Raman (TR3) experiments were undertaken. Photolysis of persulphate at 250 nm generated the So4−· radical which then oxidised sodium carbonate. Resonance Raman spectra of the resulting Co3−· radical were obtained using a probe wavelength of 620 nm. Point group theory calculations and interpretation of the TR3 spectra suggest that the radical has C2v molecular symmetry.

Resonance Raman Spectra of Halogen Molecules Adsorbed on Metal Substrates

1987 ◽  
Vol 101 ◽  
Author(s):  
Takeo Matsushima ◽  
Masahiro Kawasaki ◽  
Hiroyasu Sato
Keyword(s):  
Substrate Surface ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Band Intensity ◽  
Similar Increase ◽  
Metal Substrates ◽  
Excitation Profile ◽  
Molecular Transfer ◽  
Resonance Raman Spectra ◽  
The Sacrifice

ABSTRACTResonance Raman spectroscopy was used to monitor the adsorption of halogen molecules (bromine and iodine) on metal substrates. The Raman bands of chemisorbed, physisorbed and crystalline species were found in the spectra. In the case of bromine, when the temperature was raised from 77 K, the band associated with the chemisorbed species increased in intensity with the concomitant decrease in intensity of the band of crystalline species. A similar increase in the band intensity of the chemisorbed species at the sacrifice of that of the crystalline species was found on continued laser irradiation. The saturation of the band intensity of chemisorbed species was found in the latter case, however. The continued evaporation of bromine vapor onto the substrate surface at 77 K with the simultaneous monitoring of the layer thickness revealed that the initial deposit of bromine onto the substrate did not lead to the chemisorbed species. The accumulation of the crystalline species occurred in its stead. The occurrence of the molecular transfer process from the crystalline species into the chemisorbed species was suggested. The Raman excitation profile showed that bromine molecules adsorbed on a substrate do not dissociate in the wavelength range studied (16000-22000 cm-1). The excitation profile is to be given by Albrecht's A term and roughly corresponds to the absorption spectrum of thin film of bromine on the substrate, which is very difficult to obtain directly.

Resonance Raman Spectroscopy of Photolabile Transition Metal Carbonyls: Controlled Photoalteration with Continuous Wave Lasers to Record Spectra of Reactants or Transient Species

2003 ◽  
Vol 57 (8) ◽  
pp. 960-969 ◽  
Author(s):  
Laurence C. Abbott ◽  
Caroline J. Feilden ◽  
Clare L. Anderton ◽  
John N. Moore
Keyword(s):  
Transition Metal ◽  
Continuous Wave ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Inert Atmosphere ◽  
Metal Carbonyls ◽  
Transient Species ◽  
Transition Metal Carbonyls ◽  
Resonance Raman Spectra ◽  
High Level

A method has been developed that enables resonance Raman spectra of photolabile species in solution to be recorded under conditions where the level of photoalteration is controlled: a low level enables reactant spectra to be recorded, whereas a high level enables the spectra of short-lived transient species to be recorded in real time using continuous-wave (CW) lasers and standard Raman detection equipment. The design includes a sealed flow system, enabling air-sensitive species to be studied under an inert atmosphere. A simple theoretical model has been developed to aid the interpretation of experimental results, and its applicability is demonstrated. Controlled photoalteration and its theory are demonstrated with 413.1-nm excitation of carbonmonoxymyoglobin (MbCO), which generates deoxymyoglobin (deoxy-Mb) on photolysis, and for which the spectra of both species are well established. The methods have also been applied to two air-sensitive, photolabile transition metal carbonyls using 514.5-nm wavelength excitation: for Cp2Mo2(CO)6 (Cp = η5–C5H5), increasing levels of photoalteration result only in a decrease in the parent band intensities, relative to the solvent bands; for Cp2Fe2(CO)4, increasing levels of photoalteration result in the appearance of additional bands that are assigned to the transient species CpFe(μ–CO)3FeCp, formed following the loss of a CO ligand.

scholarly journals Ruthenium(II)-bis(4′-(4-ethynylphenyl)-2,2′:6′, 2″-terpyridine) — A versatile synthon in supramolecular chemistry. Synthesis and characterization

2011 ◽  
Vol 9 (6) ◽  
pp. 990-999 ◽  
Author(s):  
Ronald Siebert ◽  
Florian Schlütter ◽  
Andreas Winter ◽  
Martin Presselt ◽  
Helmar Görls ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Supramolecular Chemistry ◽  
Photophysical Properties ◽  
Resonance Raman Spectroscopy ◽  
Bathochromic Shift ◽  
Resonance Raman ◽  
Electronic Effects ◽  
Charge Transfer Transition ◽  
Click Reactions ◽  
Ligand Charge Transfer

AbstractA homoleptic ethynyl-substituted ruthenium(II)-bisterpyridine complex representing a versatile synthon in supramolecular chemistry was synthesized and analyzed by NMR spectroscopy, mass spectrometry and X-ray diffractometry. Furthermore, its photophysical properties were detailed by UV/Vis absorption, emission and resonance Raman spectroscopy. In order to place the results obtained in the context of the vast family of ruthenium coordination compounds, two structurally related complexes were investigated accordingly. These reference compounds bear either no or an increased chromophore in the 4′-position. The spectroscopic investigations reveal a systematic bathochromic shift of the absorption and emission maximum upon increasing chromophore size. This bathochromic shift of the steady state spectra occurs hand in hand with increasing resonance Raman intensities upon excitation of the metal-to-ligand charge-transfer transition. The latter feature is accompanied by an increased excitation delocalization over the chromophore in the 4′-position of the terpyridine. Thus, the results presented allow for a detailed investigation of the electronic effects of the ethynyl substituent on the metal-to-ligand charge-transfer states in the synthon for click reactions leading to coordination polymers.

Sign in / Sign up

Export Citation Format

Share Document