Transient infrared spectroscopy

Dyer R B, Einarsdottir 6, Killough P M, Lopez-Garriga J J and Woodruff W H 1989 Transient binding of photodissociated CO to of eukaryotic cytochrome oxidase at ambient temperature. Direct evidence from time-resolved infrared spectroscopy J. Am. Chem. Soc. Ill 7657-9... 

The objective of this study is to investigate the mechanism of propylene oxidation by a transient infrared spectroscopic technique over Rh/Al203. This technique allows simultaneous measurement of the dynamics of adsorbed species by in situ infrared spectroscopy and the product formation profile by mass spectrometry. 

Troullier, A., Reinstadler, D., Dupont, Y, Naumann, D., and Forge, V. (2000). Transient non-native secondary structures during the refolding of alpha-lactalbumin detected by infrared spectroscopy. Nat. Struct. Biol. 7, 78-86. 

The spectroscopy, reaction kinetics, and photophysics of coordinatively unsaturated metal carbonyls generated in the gas phase via UV photolysis are probed via transient infrared spectroscopy. The parent compounds that have been used to generate coordinatively unsaturated species are Fe(CO)5, Cr(C0)5 and Mn2(CO)io- In contrast to what is observed in solution phase, photolysis of these compounds produces a variety of coordinatively unsaturated photoproducts. 

Despite the considerable amount of information that has been garnered from more traditional methods of study it is clearly desirable to be able to generate, spectroscopically characterize and follow the reaction kinetics of coordinatively unsaturated species in real time. Since desired timescales for reaction will typically be in the microsecond to sub-microsecond range, a system with a rapid time response will be required. Transient absorption systems employing a visible or UV probe which meet this criterion have been developed and have provided valuable information for metal carbonyl systems [14,15,27]. However, since metal carbonyls are extremely photolabile and their UV-visible absorption spectra are not very structure sensitive, the preferred choice for a spectroscopic probe is time resolved infrared spectroscopy. Unfortunately, infrared detectors are enormously less sensitive and significantly slower... 

Agnelli, M., Swaan, H. M., Marquez-Alvarez, C., Martin, G. A., and Mirodatos, C. 1998. CO hydrogenation on a nickel catalyst. II. A mechanistic study by transient kinetics and infrared spectroscopy. J. Catal. 175 117-28. 

Infrared Measurements. Elementary-step models can be fit to transient gas-phase data (5) which are obtained by the methods described above. The models will then predict the surface intermediate concentration during transients and at steady state. It is clear that it is also important to observe these surface species experimentally, during transients as well as at steady state. Infrared spectroscopy can be used during catalysis in the presence of the gas phase, so it plays an important role in transient studies. 

The significance of the coupling of micro- and macrorelaxations for resonance phenomena observed in catalytic systems under forced periodic operation (cycling) (15) implies that the wave-front analysis of transients of this kind can eventually suggest a more effective strategy in seeking the optimal conversion and selectivity. Finally the existence of certain surface structures and complexes could be established, if the transients of the surface intermediates will be followed e.g. by infrared spectroscopy (see e.g. (16, 17)). 

Bemath, P. F. (1990), High Resolution Infrared Spectroscopy of Transient Molecules, Ann. Rev. Phys. Chem. 41,91. 

G. Hungerford, The application of spark source fluorescence lifetime spectroscopy to the study of infrared fluorescence, transient species and DCM, Ph.D. thesis. University of Strathclyde, Glasgow, Scotland (1991). 

Lamberti, C., Groppo, G., Spoto, S., Bordiga, S., and Zecchina, A. (2007) Infrared spectroscopy of transient surface species. Adv. Catal, 51,1-74. 

Probing Metalloproteins Electronic absorption spectroscopy of copper proteins, 226, 1 electronic absorption spectroscopy of nonheme iron proteins, 226, 33 cobalt as probe and label of proteins, 226, 52 biochemical and spectroscopic probes of mercury(ii) coordination environments in proteins, 226, 71 low-temperature optical spectroscopy metalloprotein structure and dynamics, 226, 97 nanosecond transient absorption spectroscopy, 226, 119 nanosecond time-resolved absorption and polarization dichroism spectroscopies, 226, 147 real-time spectroscopic techniques for probing conformational dynamics of heme proteins, 226, 177 variable-temperature magnetic circular dichroism, 226, 199 linear dichroism, 226, 232 infrared spectroscopy, 226, 259 Fourier transform infrared spectroscopy, 226, 289 infrared circular dichroism, 226, 306 Raman and resonance Raman spectroscopy, 226, 319 protein structure from ultraviolet resonance Raman spectroscopy, 226, 374 single-crystal micro-Raman spectroscopy, 226, 397 nanosecond time-resolved resonance Raman spectroscopy, 226, 409 techniques for obtaining resonance Raman spectra of metalloproteins, 226, 431 Raman optical activity, 226, 470 surface-enhanced resonance Raman scattering, 226, 482 luminescence... 

Selected entries from Methods in Enzymology [vol, page(s)] Biomolecular vibrational spectroscopy, 246, 377 Raman spectroscopy of DNA and proteins, 246, 389 resonance Raman spectroscopy of metalloproteins, 246, 416 structure and dynamics of transient species using time-resolved resonance Raman spectroscopy, 246, 460 infrared spectroscopy applied to biochemical and biological problems, 246, 501 resonance Raman spectroscopy of quinoproteins, 258, 132. 

The double )5-scission pathway becomes dominant in bicyclic systems (Equations (7)-(9) and Scheme 13). Thus, cyclopentene ozonide (69) gives cyclopropane (Equation (7)) <68TL329l>. Photolysis of the ozonide derived from 1,4-benzodioxins (70) provides a method for the preparation of labile o-benzoquinones (71) (Scheme 13) <87JOC56l6>. Photolysis can also provide a route to unstable compounds and transient species such as the aziridine-2,3-dione (72) (Equation (8)), identified at 77 K using infrared spectroscopy <80JA6902>. Relatively unstable azacarbapenems (73) have been prepared by photolysis of tricyclic compounds containing a cyclobutene ozonide (Equation (9)). On silica, the 1,2,4-trithiolane (74) underwent photo-equilibration (Equation (10)) with the 1,3-dithetane (75) and sulfur. 

The term 1 or h indicates low or high coverage of adsorbed ethene, as inferred from ethene exposures.h TPD, temperature-programmed desorption LITD, laser-induced thermal desorption 1 FT-MS, Fourier-transform mass spectrometry SIMS, secondary-ion mass spectrometry MS, mass spectrometry T-NEXAFS, transient near-edge X-ray absorption fine structure spectroscopy RAIRS, reflection-absorption infrared spectroscopy. d Data for perdeut-erio species.1 Estimated value. 

Transient two-dimensional infrared spectroscopy - towards measuring ultrafast structural dynamics... 

Transient nvo-dirttcnsml infrared spectroscopy towards measuring ultra fast structural dy namics... 

These conclusions were supported by transient absorption spectroscopy, which revealed signals corresponding to the formation of the diimine radical anion, with lifetimes in close agreement with the luminescence lifetimes. Time-resolved infrared spectroscopy of the acetylide C = C bonds provides further conclusive evidence for the MLCT assignment. Thus, in the ground state IR spectrum of 4, there are two v(C=C) bands at 2115 and 2124 cm-1, whilst the step-scan FTIR difference spectrum obtained 50 ns after irradiation at 355 nm reveals bleaching of the parent bands, and the formation... 

A quite different approach to radiofrequency, microwave and infrared spectroscopy is that known as Fourier transform (FT) spectroscopy. As we shall see, this method of recording the spectra of transient molecular species is particularly appropriate in combination with the use of pulsed gas nozzles. For this reason it has proved to be a powerftd technique for the study of weakly bound dimer complexes formed in supersonic gas expansions. It has, however, also been used for the study of diatomic molecules, both... 

Dougherty TP, Heilweil EJ. Transient infrared spectroscopy of (jj5-C5H5)Co(CO)2 photoproduct reactions in hydrocarbon solutions. J Chem Phys 1994 100(5) 4006-4009. 

Grubbs WT, Dougherty TP, Heilweil EJ. Vibrational energy redistribution in Cp Ir(CO)2 (Cp = j5-pentamethylcyclopentadienyl) studied by broadband transient infrared spectroscopy. Chem Phys Lett 1994 227 480-484. 

Arrivo SM, Kleiman VD, Dougherty TP, Heilweil EJ. Broadband femtosecond transient infrared spectroscopy using a 256 x 256 element indium antimonide focal-plane detector. Optics Lett 1997 22(19) 1488-1490. 

Beckerle JD, Cavanagh RR, Casassa MP, Heilweil EJ, Stephenson JC. Subpicosecond transient infrared spectroscopy of adsorbates vibrational dynamics of CO/Pt(lll). J Chem Phys 1991 95 5403-5418. 

The area in which matrix isolation is perhaps of greatest value is the stabilization of transient species such as free radicals and high-temperature vapors. Until quite recently, infrared spectroscopy was utilized almost exclusively for the vibrational studies of matrix-isolated species. With the introduction of laser sources and the development of more sensitive, electronic, light detection systems, Raman matrix-isolation studies are now feasible and have recently been applied to a limited number of unstable inorganic fluoride species including the molecules OF (5) and C1F2 (6). Both of these species were formed for Raman study by a novel technique that utilizes the... 

---