Download or read book Infrared Multiple photon Dissociation of Small Organic Sulfoxides written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Infrared Multiple photon Dissociation of Small Organic Sulfoxides written by Marko Peter Banjavčiʹc and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The infrared multiple-photon dissociation of several small organic sulfoxides was studied in order to provide some insight in the dissociative product channels for this class of molecules. Vibrational excitation was achieved with a TEA CO2 laser and photofragments were identified with a laser ionized time of light mass spectrometer. A beam of 10.5 eV photons generated in a static xenon gas tripling cell from a tightly focused Nd:YAG third harmonic beam of light was used to ionize the molecules and fragment species. The photoionization mass spectra were found to contain fewer fragmentation species than the corresponding electron impact ionization mass spectra. Numerous product species were observed from skeletal rearrangement reactions despite the lower level of energy excitation from the photoionization process. The infrared photolysis wavelength dependence of dimethyl sulfoxide indicated that the maximum abundance for the major fragmentation species occurred at (or near) 1085.8 cm−1. The major products at 1085.8 cm−1 were [H3CSO]+ and [CH3]+. Minor products were also observed at a higher output power threshold like the skeletal rearrangement species [H3CS]+ and [OCH3]+. With the infrared photolysis wavelength dependence of methyl phenyl sulfoxide, the major product species ([CH3]+ and [OSCH3]+) had a maximum abundance near 1086.9 cm−1 . Small mass fragment species (like [HCS]+, [C4H5]+ and [C4H3]+) had a maximum abundance near 1080 cm−1 while large mass fragment species ([C6H8S]+ and [C6H5SO]+) had a maximum abundance that was further red-shifted (1058.9 and 1050.4 cm−1 , respectively). The photolysis at 1085.8 cm−1 generated the high mass fragment species ([C6H5SO]+, [C6H8S]+ and [C5H5S]+) at all CO2 laser output powers but a plateau in the abundance was observed at higher output powers. The smaller mass fragmentation species only appeared after a threshold power was surpassed. The maximum abundance for the various fragmentation species of sec-butyl methyl sulfoxide occurred near 1072 cm−1. The CO2 laser output power dependence for the formation of the butane, butyl and butene ions indicated all three were generated at all output powers with an abundance plateau or decline occurring at higher output powers. Fragmentation species were observed from the butyl group primary products with the power threshold increasing for the sequentially smaller secondary species.
Download or read book Characterization of Several Small Biologically Relevant Molecules by Infrared Multiple Photon Dissociation Spectroscopy and Electronic Structure Calculations written by Sabrina M. Martens and published by . This book was released on 2011 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Infrared multiple photon dissociation (IRMPD) spectroscopy has been coupled with electronic structure calculations in order to elucidate the structures of several small biological molecules including: uracil, 5-fluorouracil, 5-fluorocytosine, ferulic acid, and a number of their related analogs. IRMPD is a powerful technique, that when combined with electronic structure calculations can provide convincing evidence for the structural characterization of ions in the gas phase. Isomers of uracil and 5-fluorouracil (5-FU) have been characterized by calculations performed at the MP2(full)/aug-cc-pVTZ level of theory; however, infrared multiple photon dissociation spectroscopy experiments proved to be unsuccessful for these species. Geometry optimization and frequency calculations have isolated the dominant isomer(s) for neutral and deprotonated uracil and 5-fluorouracil, along with several cluster interactions involving water, methanol, ammonia, and methylamine. For both uracil and 5-FU, a single relevant neutral isomer was determined, with each isomer existing in the diketo, as opposed to the enol form. Following the deprotonation of this neutral isomer, both uracil and 5-FU were permitted to form anionic cluster ions with water, methanol, ammonia, or methylamine, and based on the relative Gibbs free energies (298 K) of the calculated isomers, relevant cluster interactions were determined. For each cluster, several sites of intramolecular interaction were found to exist; however, interaction at the site of deprotonation was the most favourable in every instance. Ionic hydrogen bond interactions have been found in several clusters formed by 5-fluorocytosine (5-FC).
Download or read book Mass selected Infrared Multiple photon Dissociation as a Structural Probe of Gaseous Ion molecule Complexes written by Richard Alexander Marta and published by . This book was released on 2009 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass-selected infrared multiple photon spectroscopy (IRMPD), Fourier transform ion cyclotron resonance (FT-ICR) kinetic experiments, RRKM and electronic structure calculations have been performed in order to propose a complex mechanism involving the formation of the proton-bound dimer of water (H5O2) from 1,1,3,3-tetrafluorodimethyl ether. It has been found that the reaction is facilitated by a series of sequential exothermic bimolecular ion-molecule reactions. Evidence for the dominant mechanistic pathway involving the reaction of CF2H-O=CHF2, an ion of m/z 99, with water is presented. The primary channel occurs via nucleophilic attack of water on the ion of m/z 99 (CF2H-O=CHF), to lose formyl fluoride and yield protonated difluoromethanol (m/z 69). Association of a second water molecule with protonated difluoromethanol generates a reactive intermediate which decomposes via a 1,4-elimination to release hydrogen fluoride and yield the proton-bound dimer of water and formyl fluoride (m/z 67). The 1,4-elimination of hydrogen fluoride is found to be strongly supported by the results of both RRKM theory and electronic structure calculations. Lastly, the elimination of formyl fluoride occurs by the association of a third water molecule to produce H5O2 (m/z 37). The most probable isomeric forms of the ions with m/z 99 and 69 were found using IRMPD spectroscopy and electronic structure theory calculations. Thermochemical information for reactant, transition and product species was obtained using MP2/aug-cc-pVQZ//MP2(full)/6-31G(d) level of theory.
Download or read book Infrared Multiple Photon Dissociation Spectroscopy on Biomolecular Ions written by Tjalling Sybren Joannes Antonius de Boer and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structures of Gaseous Ions by Infrared Multiple Photon Dissociation IRMPD Spectroscopy written by Khadjch Rajabi and published by . This book was released on 2010 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Infrared Multiple Photon Dissociation Spectra of Gaseous Ions written by Dilrukshi Manjalika Patuwathavithana Peiris and published by . This book was released on 1994 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structures of Gaseous Ions by Infrared Multiple Photon Dissociation IRMPD Spectroscopy written by Khadjch Rajabi and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1999 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tables of Spectral Data for Structure Determination of Organic Compounds written by Ernö Pretsch and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although numerical data are, in principle, universal, the compilations presented in this book are extensively annotated and interleaved with text. This translation of the second German edition has been prepared to facilitate the use of this work, with all its valuable detail, by the large community of English-speaking scientists. Translation has also provided an opportunity to correct and revise the text, and to update the nomenclature. Fortunately, spectroscopic data and their relationship with structure do not change much with time so one can predict that this book will, for a long period of time, continue to be very useful to organic chemists involved in the identification of organic compounds or the elucidation of their structure. Klaus Biemann Cambridge, MA, April 1983 Preface to the First German Edition Making use of the information provided by various spectroscopic tech niques has become a matter of routine for the analytically oriented organic chemist. Those who have graduated recently received extensive training in these techniques as part of the curriculum while their older colleagues learned to use these methods by necessity. One can, therefore, assume that chemists are well versed in the proper choice of the methods suitable for the solution of a particular problem and to translate the experimental data into structural information.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2000 with total page 956 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directory of Graduate Research written by and published by . This book was released on 2001 with total page 1850 pages. Available in PDF, EPUB and Kindle. Book excerpt: Faculties, publications and doctoral theses in departments or divisions of chemistry, chemical engineering, biochemistry and pharmaceutical and/or medicinal chemistry at universities in the United States and Canada.
Download or read book Visible Light Photocatalysis in Organic Chemistry written by Corey R.J. Stephenson and published by John Wiley & Sons. This book was released on 2018-05-29 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling the need for a ready reference that reflects the vast developments in this field, this book presents everything from fundamentals, applications, various reaction types, and technical applications. Edited by rising stars in the scientific community, the text focuses solely on visible light photocatalysis in the context of organic chemistry. This primarily entails photoinduced electron transfer and energy transfer chemistry sensitized by polypyridyl complexes, yet also includes the use of organic dyes and heterogeneous catalysts. A valuable resource to the synthetic organic community, polymer and medicinal chemists, as well as industry professionals.
Download or read book Mass Spectrometry written by Edmond de Hoffmann and published by Wiley. This book was released on 2001-10-10 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers a complete overview of the principles, theories and key applications of modern mass spectrometry in this introductory textbook. Following on from the highly successful first edition, this edition is extensively updated including new techniques and applications. All instrumental aspects of mass spectrometry are clearly and concisely described; sources, analysers and detectors. * Revised and updated * Numerous examples and illustrations are combined with a series of exercises to help encourage student understanding * Includes biological applications, which have been significantly expanded and updated * Also includes coverage of ESI and MALDI
Download or read book INIS Atomindeks written by and published by . This book was released on 1986 with total page 1390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Devil s Gate written by Thea Harrison and published by Teddy Harrison LLC. This book was released on 2017-08-22 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title was previously published and is being rereleased by the author. It has not been revised. As a coroner, medusa Seremela Telemar has always felt more comfortable chatting over a dead body than over drinks. But when her wild niece, Vetta, runs off to Devil’s Gate, a lawless town that sprung up overnight in a modern-day gold rush, she knows she has to extricate her before the rebellious girl gets into real trouble. Vampyre Duncan Turner is not about to let his new co-worker go into that chaotic Wild West town alone. His Vampyric power and lawyer smarts make him the perfect ally, and the fact that he already had his eye on Seremela for more…personal reasons, doesn’t hurt matters. Any romantic thoughts are put on hold, however, when they arrive at Devil’s Gate and learn Vetta is set to hang by morning. In order to save Vetta and themselves, Seremela and Duncan are going to have to fight fire with force, and magic with fangs. And pray they make it out of Devil’s Gate alive.
Download or read book Concepts and Methods of 2D Infrared Spectroscopy written by Peter Hamm and published by Cambridge University Press. This book was released on 2011-02-24 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2D infrared (IR) spectroscopy is a cutting-edge technique, with applications in subjects as diverse as the energy sciences, biophysics and physical chemistry. This book introduces the essential concepts of 2D IR spectroscopy step-by-step to build an intuitive and in-depth understanding of the method. This unique book introduces the mathematical formalism in a simple manner, examines the design considerations for implementing the methods in the laboratory, and contains working computer code to simulate 2D IR spectra and exercises to illustrate involved concepts. Readers will learn how to accurately interpret 2D IR spectra, design their own spectrometer and invent their own pulse sequences. It is an excellent starting point for graduate students and researchers new to this exciting field. Computer codes and answers to the exercises can be downloaded from the authors' website, available at www.cambridge.org/9781107000056.
