Infrared multiple-photon dissociation

The Exxon data 7or iron with methanol also does not show size selective behavi or(52). The Exxon group has been able to show by infrared multiple photon dissociation that the 0-H bond breaks forming methoxy on these small iron c usters(3h). This is consistent with the behavior of methanol at room temperature on iron... 

T. D. Frigden, L. MacAleese, T. B. McMahon, J. Lemaire, and P. Maitre, Gas phase infrared multiple photon dissociation spectra of methanol, ethanol and propanol proton bound dimers, protonated propanol and the propanol/water proton bound dimer. Phys. Chem. Chem. Phys. 8, 955 966 (2006). 

Fragmentation of peptides can also be observed with FTICR instruments. Infrared multiple photon dissociation (IRMPD) and electron capture dissociation (ECD) have been introduced as two alternative dissociation methods to the low-energy CID method. The IRMPD method produces many fragments that make the spectrum very complex and difficult to interpret. Some of the fragment types observed with IRMPD are b and y type ions or these ions that have lost ammonia or water. However, most of them are not these types of fragment ions. 

Iron clusters exhibit facile chemisorption toward methanol, the reaction proceeding with little or no cluster-size selectivity. An interesting feature of this system is that the chemisorption rate constants are nearly identical toward various isotopic sjjecies (CH3OH, CH30D,CD3 0H). If dissociation of a C—H or O—H bond was the initial step, then this should be manifested in an observable kinetic isotope effect. Thus the initial chemisorption step most likely involves the lone-pair orbital localized on the oxygen atom. More extensive studies of the chemistry of the Fe methanol system have been explored using infrared multiple-photon dissociation spectroscopy. These results are discussed in detail in Section Vlll. 

Vibrational spectroscopy is an important probe used to determine the bonding and structural properties of molecules. Powerful techniques such as electron energy loss spectroscopy (EELS) have been developed, which allow one to obtain the vibrational properties of molecules chemisorbed upon surfaces. Due to low concentration, the highly reactive nature of the clusters, and the large number of possible species which are typically present in the cluster beams used to date, unconventional techniques are required in order to obtain spectroscopic information. One unconventional but powerful technique, infrared multiple photon dissociation (IRMPD), has recently been applied to the study of the vibrational properties of gas-phase metal clusters upon which one or more molecules have been chemisorbed. This same technique, IRMPD, has previously been used to obtain the vibrational spectra of ions, species for which it is difficult to apply conventional absorption techniques. 

As mentioned earlier, CPMD simulations were carried out at 300K on deprotonated phosphorylated serine (p-ser-H) , and the resultant extracted spectrum correlates with the experimental IR spectrum obtained by the recently-developed InfraRed Multiple Photon Dissociation (IRMPD) technique, which was first described in this chapter in Volume 39. 

A wide variety of lasers have been used in combination with trapping mass spectrometers. Two lasers in particular are incorporated already into many commercial mass spectrometers the CO2 (X= 10.6 pm or 0.12 eV photon ) and nitrogen (X=337 nm or 3.68 eV photon ) lasers. The former is used for performing infrared multiple photon dissociation (IRMPD) experiments (mostly in ICR instruments, see Section 9.3) while the latter is used commonly in MALDl ionization sources. Other commonly-used lasers are Q-switched Nd YAG lasers (fundamental X= 1064 nm... 

Oomens, J. Sartakov, B.G. Meijer, G. VonHelden, G. Gas-phase infrared multiple photon dissociation spectroscopy of mass-selected molecular ions. Int. J. Mass Spectrom. 2006, 254,1-19. 

Stephenson, J.L. Booth, M.M. Shalosky, J.A. Eyler, J.R. Yost, R.A. Infrared multiple-photon dissociation in the quadrupole ion-trap via a multipass optical arrangement. J. Am. Soc. Mass Spectrom. 1994,5, 886-893. 

Prison, G. van der Rest, G. Turecek, F. Besson, T. Lemaire, J. Maitre, P Chamot-Rooke, J. Structure of electron-capture dissociation fragments from charge-tagged peptides probed by tunable infrared multiple photon dissociation. J. Am. Chem. Soc. 2008, 130, 14916-14917. 

Atkins, C.G. Rajabi, K. GiUis, E.A.L. Fridgen, T.D. Infrared multiple photon dissociation spectra of proton- and sodium ion-bound glycine dimers in the N-H and O-H stretching region. J. Phys. Chem. A. 2008,112,10220-10225. 

Polfer NC. Infrared multiple photon dissociation spectroscopy of trapped ions. Chem Soc Rev. 2011 40 2211-21. 

Citir M, Steimett EMS, Oomens J, Steill JD, Rodgers MX, Armentrout PB. Infrared multiple photon dissociation spectroscopy of cationized cysteine effects of metal cation size on gas-phase conformation. Int J Mass Spectrom. 2010 297 9-17. 

Nucleotides are covered elsewhere in this volume but worthy of mention is the cyclic 3, 5 -adenosine monophosphate anion (cAMP-H) , generated in gaseous species by electrospray ionization (ESI) and stored in an ion-trap mass spectrometer. This has been investigated by mass-resolved infrared multiple photon dissociation (IRMPD) spectroscopy in the 900 1800 cm fingerprint range using the powerful and continuously-tunable radiation from a free electron laser. Further details of this IRMPD application are given in the mass spectrometry section later. 

The types of action spectroscopy presented in this book include IR-UV ion dip spectroscopy for neutral species and Infrared Multiple Photon Dissociation... 

Peiris DM, Cheeseman MA, Ramanathan R, Eyler JR (1993) Infrared multiple photon dissociation spectra of gaseous ions. J Phys Chem 97 7839-7843... 

Pameix P, Basire M, Calvo F (2013) Accurate modeling of infrared multiple photon dissociation spectra the dynamical role of anharmonicities. J Phys Chem A 117 3954—3959... 

Wu RH, McMahon TB (2007) Infrared multiple photon dissociation spectroscopy as structural confirmation for GlyGlyGlyH(-l-) and AlaAlaAlaH(-t) in the gas phase. Evidence for amide oxygen as the protonation site. J Am Chem Soc 129 11312... 

Prell JS, Chang TM, Biles JA, Berden G, Oomens J, Williams ER (2011) Isomer population analysis of gaseous ions from infrared multiple photon dissociation kinetics. J Phys Chem A 115 2745-2751... 

Burt MB, Fridgen TD (2013) Gas-phase structures of Pb2-i—cationized phenylalanine and glutamic acid determined by infrared multiple photon dissociation spectroscopy and compu-tatirmal chemistry. J Phys Chem A 117 1283-1290... 

Burt MB, Decker SGA, Atkins CG, Rowsell M, Peremans A, Pridgen TD (2011) Structures of bare and hydrated [Pb(AminoAcid-H)](+) complexes using infrared multiple photon dissociation spectroscopy. J Phys Chem B 115 11506-11518... 

Atkins CG, Banu L, Rowsell M, Blagojevic V, Bohme DK, Pridgen TD (2009) Structure of [Pb(Gly-H)](-i-) and the monosolvated water and methanol solvated species by infrared multiple-photon dissociation spectroscopy, energy-resolved collision-induced dissociation, and electronic structure calculations. J Phys Chem B 113 14457-14464... 

Verkerk UH, Zhao JP, Saminathan IS, Lau JKC, Oomens J, Hopkinstm AC, Sin KWM (2012) Infrared multiple-photon dissociation spectroscopy of tiipositive ions lanthanum-tryptophan complexes. Inorg Chem 51 4707-4710... 

Rajabi K, Pridgen TD (2008) Structures of aliphatic amino acid proton-bound dimers by infrared multiple photon dissociation spectroscopy in the 700-2000 cm(—1) region. J Phys Chem A 112 23-30... 

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