Resonance Raman Spectra and Structure of Partially Oxidized Magnus' Salt

1979 ◽  
Vol 34 (7) ◽  
pp. 986-988 ◽  
Author(s):  
G. C. Papavassiliou ◽  
T. Theophanides

Abstract The partially oxidized form of Magnus' salt has been studied by resonance Raman spectroscopy (RRS) and it has been established that the oxidized form is a chlorine bridged chain polymer. The spectra show intense progressions, υν, where ν, is the symmetric ···X-Pt(IV)-X··· stretching mode, and v the quantum number

1999 ◽  
Vol 19 (1-4) ◽  
pp. 71-74 ◽  
Author(s):  
Xuming Zheng ◽  
David Lee Phillips

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.


2012 ◽  
Vol 35 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Magdalena Laskowska ◽  
Łukasz Laskowski ◽  
Kazimierz Dzilinski

Abstract Mesoporous silica SBA-15 functionalized by (1,4,8,11-tetraazacyclotetradecane) cyclam groups containing nickel ions (Ni-cyclam) was synthesized by two different approaches, and investigated by resonance Raman spectroscopy. Vibrational features of organometallic moleculess are analyzed for (Ni-cyclam) groups grafted in the silica pores. An assignment of bands in resonance Raman spectra was done to monitor the structure and properties of the mesoporous silica material with regard to the methods of synthesis used in this study. It was shown, that Raman scattering can be useful for probing of functionalization's efficiency of mesoporous silica. On the base of the resonance investigation: Raman and EPR spectroscopy, distribution of the functional groups inside pores can be determined. In the present article the Raman spectroscopy is treat as a complementary research to EPR investigation. It was shown that a clustering of the active groups alter significantly the resonance Raman spectra through broadening and shifts of the corresponding bands in comparison with separated molecules. Results obtained from the analysis of the resonance Raman spectra indicate significant differences between the samples prepared by the two procedures. The discussion of the Raman results was referred to EPR results, and on the base of this authors concluded about correct achievement of the functionalization.


1980 ◽  
Vol 35 (10) ◽  
pp. 1272-1273 ◽  
Author(s):  
Robin J. H. Clark ◽  
Mohamedally Kurmoo ◽  
K. D. Buse ◽  
H. J. Keller

Abstract The partially oxidized cis-Pt(NH3)2(SCN)2I has been studied by resonance Raman spectroscopy. A progression in the symmetric I-PtIV-I vibration (v1 = 120.1 cm-1), reaching as far as 8 v1, has been observed. The compound Pt(NH3)2(SCN)2I could be identified as a mixed valence solid with neutral, linear PtII···I-PtIV chains.


1999 ◽  
Vol 19 (1-4) ◽  
pp. 311-316 ◽  
Author(s):  
Susan M. Tavender ◽  
Steven A. Johnson ◽  
Daniel Balsom ◽  
Anthony W. Parker ◽  
Roger H. Bisby

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Anneli Ehlerding ◽  
Ida Johansson ◽  
Sara Wallin ◽  
Henric Östmark

Resonance-enhanced Raman spectroscopy has been used to perform standoff measurements on nitromethane (NM), 2,4-DNT, and 2,4,6-TNT in vapor phase. The Raman cross sections for NM, DNT, and TNT in vapor phase have been measured in the wavelength range 210–300 nm under laboratory conditions, in order to estimate how large resonance enhancement factors can be achieved for these explosives. The results show that the signal is enhanced up to 250,000 times for 2,4-DNT and up to 60,000 times for 2,4,6-TNT compared to the nonresonant signal at 532 nm. Realistic outdoor measurements on NM in vapor phase at 13 m distance were also performed, which indicate a potential for resonance Raman spectroscopy as a standoff technique for detection of vapor phase explosives. In addition, the Raman spectra of acetone, ethanol, and methanol were measured at the same wavelengths, and their influence on the spectrum from NM was investigated.


The Analyst ◽  
2018 ◽  
Vol 143 (24) ◽  
pp. 5950-5958 ◽  
Author(s):  
Rekha Gautam ◽  
Joo-Yeun Oh ◽  
Rakesh P. Patel ◽  
Richard A. Dluhy

A method to acquire the Raman spectra of sub-surface components using diffusely focused radiation in a microscope sampling configuration is described.


Clay Minerals ◽  
1988 ◽  
Vol 23 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Y. Soma ◽  
M. Soma

AbstractResonance Raman spectroscopy has been used to observe the formation of cation radicals in the adsorption of N,N,N',N'-tetramethylbenzidine (TMBD), benzidine, N,Ndimethylaniline (DMA) and aniline on Na-, Cu- and Fe-montmorillonites. Cation radicals of benzidine and TMBD, and their dications were formed at acid sites on the montmorillonite surface, or through the reduction of Cu or Fe interlayer ions, and were adsorbed in the interlayer. Their structures are represented by biphenoquinone type structure, where the inter-ring CC bond and the ring C-N bond have double bond characters. It was demonstrated from Raman spectra that DMA and aniline adsorbed on Cu-montmorillonite from the vapour phase dimerize to form TMBD and benzidine dications.


Resonance Raman spectroscopy involves laser excitation within an absorption band of the sample. Certain vibrational modes, those which couple to the electronic transition, exhibit greatly increased Raman scattering in the resulting spectrum. Sensitivity approaches that of absorption spectrophotometry, while the high resolution characteristic of vibrational spectroscopy is preserved, even in solution at room temperature. If the resonant electronic transition is associated with a site of biological activity, then the technique offers a sensitive probe for structural features of the site. Haem proteins afford particularly informative resonance Raman spectra, with a rich assortment of porphyrin ring vibrations, which can be classified and analysed via their symmetry properties. Certain of these frequencies are sensitive to the structural concomitants of spin- and oxidation-state changes of the haem group. These can be used to monitor the structural consequences of ligation or electron transfer in haem proteins.


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