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Investigation Of Gas Phase Metal Ion Complexes Using Infrared Multiple Photon Dissociation Spectroscopy And Density Functional Theory Calculations
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Book Synopsis Investigation of Gas-phase Metal Ion Complexes Using Infrared Multiple Photon Dissociation Spectroscopy and Density Functional Theory Calculations by : Ryan Patrick Dain
Download or read book Investigation of Gas-phase Metal Ion Complexes Using Infrared Multiple Photon Dissociation Spectroscopy and Density Functional Theory Calculations written by Ryan Patrick Dain and published by . This book was released on 2010 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: A combination of theoretical chemistry and "action" spectroscopy has become the most used tool for the exploration of gas-phase molecular ions. In this study, density functional theory (DFT) calculations were used to test the validity of conclusions drawn from the results of a matrix-isolation infrared (MI-IR) experiment and develop a modeling method that could be used for metal-coordinating chlorate ion pairs. That modeling method was then used in comparison with experimental infrared multiple photon dissociation (IRMPD) spectroscopy to determine the structures of metal-chlorate anions. In addition to structural information, the effect of the modeling method on spectral correlation was also investigated.
Book Synopsis Chiral Analysis by : Kenneth W. Busch
Download or read book Chiral Analysis written by Kenneth W. Busch and published by Elsevier. This book was released on 2011-10-13 with total page 721 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chiral Analysis covers an important area of analytical chemistry of relevance to a wide variety of scientific professionals. The target audience is scientific professionals with an undergraduate background in chemistry or a related discipline, specifically organic chemists, researchers in drug discovery, pharmaceutical researchers involved with process analysis or combinatorial libraries, and graduate students in chemistry. Chapters have been written with the nonspecialist in mind so as to be self-contained.* Broad coverage - spectroscopic and separation methods covered in a single volume* Up-to-date and detailed review of the various techniques available and/or under development in this field* Contributions from leading experts in the field
Book Synopsis Structures of Gaseous Ions by Infrared Multiple Photon Dissociation (IRMPD) Spectroscopy by : Khadjch Rajabi
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:
Book Synopsis Journal by : American Chemical Society
Download or read book Journal written by American Chemical Society and published by . This book was released on 2004 with total page 978 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mass-selected Infrared Multiple-photon Dissociation as a Structural Probe of Gaseous Ion-molecule Complexes by : Richard Alexander Marta
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.
Book Synopsis The Use of Infrared Multiple Photon Dissociation and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry to Study the Thermochemical Dynamics of Dephosphorylation and the Spectral and Density Functional Theory Determined Structural Characteristics of Monosaccharide Isomers by :
Download or read book The Use of Infrared Multiple Photon Dissociation and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry to Study the Thermochemical Dynamics of Dephosphorylation and the Spectral and Density Functional Theory Determined Structural Characteristics of Monosaccharide Isomers written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Photon (vibrationally resonant) induced dissociation or action spectra, spanning the C-H-and O-H stretch regions, were then acquired for four rubidium cation-bound glycosides. Comparison of the experimental and Density Functional Theory calculated spectra revealed a network of intermolecular hydrogen bonding and rubidium attachments that provided the means to differentiate D-glucoside and D-galactoside anomers in the O-H stretching region of the infrared spectrum. In the second project, two cw-CO2 lasers were also set up for gas-phase experiments. Dephosphorylation rate constants (at varying laser powers) were obtained for both positively and negatively charged phosphopeptide ions at three different wavelengths. In these experiments, the dissociation rate constants favored the negatively charged species at all wavelengths (a result of lower activation energies) as the overall Arrhenius activation energies were independent of vibrational mode intensities.
Book Synopsis Infrared Spectroscopy of Transition Metal-Molecular Interactions in the Gas Phase by :
Download or read book Infrared Spectroscopy of Transition Metal-Molecular Interactions in the Gas Phase written by and published by . This book was released on 2008 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal-molecular complexes produced in a molecular beam are mass-selected and studied with infrared laser photodissociation spectroscopy. Metal complexes with carbon monoxide, carbon dioxide, nitrogen, water, acetylene or benzene are studied for a variety of metals. The number and intensity of infrared active bands are compared to the predictions of density functional theory calculations to derive structures, spin states and coordination numbers in these systems. These studied provide new insights into subtle details of metal-molecular interactions important in heterogeneous catalysis, metal-ligand bonding and metal ion solvation.
Book Synopsis Gas-Phase IR Spectroscopy and Structure of Biological Molecules by : Anouk M. Rijs
Download or read book Gas-Phase IR Spectroscopy and Structure of Biological Molecules written by Anouk M. Rijs and published by Springer. This book was released on 2015-06-03 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field. Review articles for the individual volumes are invited by the volume editors. Readership: research chemists at universities or in industry, graduate students.
Book Synopsis Time-resolved Infrared Spectroscopy and Density Functional Theory Study of Weak Interactions of Metal Carbonyls and Organic Solvents by : Carolyn Evans Sheffield
Download or read book Time-resolved Infrared Spectroscopy and Density Functional Theory Study of Weak Interactions of Metal Carbonyls and Organic Solvents written by Carolyn Evans Sheffield and published by . This book was released on 2010 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed laser flash photolysis of M(CO)6 (M = Cr, W) in cyclohexane with a small amount of benzene results in three sequential reactions. The first is the photodissociation of the parent to yield a M(CO)5:C6H12 complex, which takes place faster than the time resolution of our experiments. The second reaction is the replacement of the cyclohexane ligand with benzene to form a M(CO)5:C6H6 complex, in which benzene is coordinated to the metal via one side of the ring. This complex then falls apart in solution as M(CO)5 coordinates with a trace impurity in the solution that is likely water. Kinetic studies over a range of temperatures result in the following activation energies: 39 kJ/mol for the dissociation of W(CO)5:C6H6; 30 kJ/mol for conversion of Cr(CO)5:C6H12 to Cr(CO)5:C6H6; 33 kJ/mol for the dissociation of Cr(CO)5:C6H6. DFT calculations of binding energies for each complex suggest that all reactions proceed through a combination of an associative and dissociative mechanism. Further calculations of carbonyl vibrational frequencies for 13 weak metal--solvent complexes using three different density functionals: B3LYP, M06, and M06-L allowed us to calculate scale factors for predicting experimental vibrational frequencies. The scale factors are: 0.952 for B3LYP, 0.943 for M06, and 0.957 for M06-L. Using these scale factors leads to average errors in predicted experimental vibrational frequencies of less than 1% for each functional.
Book Synopsis Novel Mass Spectroscopy Techniques Implementing UV Action Spectroscopy for the Characterization of DNA Cation Radicals and Transition Metal Complexes by : Andy Dang
Download or read book Novel Mass Spectroscopy Techniques Implementing UV Action Spectroscopy for the Characterization of DNA Cation Radicals and Transition Metal Complexes written by Andy Dang and published by . This book was released on 2019 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass spectrometry has become a powerful analytical tool for the detection and characterization of chemical compounds for biological and environmental studies. Advancements in mass spectrometry including new ionization sources, ion traps, and ion activation and separation methods have allowed for enhanced structure elucidation of gas-phase ions. With electrospray ionization, multiply-charged ions in solution can now be readily transferred into the gas phase. 3D quadrupole and linear ion traps can now facilitate multi-staged tandem (MSn) mass spectrometry experiments. That is, ions (based on their mass-to-charge ratios) can be isolated and fragmented, desired fragment ions can be subsequently isolated and fragmented, and so on. Ion activation methods including collision-induced dissociation (CID), electron transfer dissociation (ETD), and UV-Vis photodissociation (UVPD) can now offer different fragmentations of precursor ions and can be combined for more robust structural analyses. Here, novel tandem mass spectrometry techniques implementing UVPD action spectroscopy for the characterization of DNA cation radicals and transition metal complexes is presented. To begin, the employment of new automated action spectroscopy methods on two different commercial mass spectrometers is discussed. UVPD action spectroscopy involves exposing isolated ions to high-energy photons and measuring the resulting photo-fragmentation as a function of photon wavelength (i.e. 200-700 nm). The generated action spectrum is representative of the gas-phase ion population's electronic excitations, and can be complemented with theoretical calculations to probe the predominant gas-phase structures. The modifications imposed on a 3D quadrupole and a linear ion trap mass spectrometer, including the optical setups needed to direct an external laser beam into the ion traps, are described in detail. Utilization of the instruments' auxiliary interface features, as well as the specific software (LabView) codes created to orchestrate automated MS[superscript]n-UVPD at specified photon wavelengths, is also reported. To compare the performance of the automated action spectroscopy methods between the two mass spectrometers, the experimental action spectrum of a well-studied compound was generated using both systems. Next, the focus is shifted towards the characterization of DNA molecules using tandem mass spectrometry with UVPD action spectroscopy. Radiative damage of DNA can lead to the formation of nucleobase cation radicals along DNA chains, resulting in nucleobase loss and strand breaks. Here, DNA-based cation radicals of guanine, 9-methylguanine, and guanosine were generated in the gas phase, and their isolated structures and intrinsic properties were probed using UVPD action spectroscopy and excited state computations. The DNA cation radicals generated in the gas phase via MS2-CID of their doubly-charged Cu(II)-complexes were isolated and subjected to MS3-UVPD at incremental wavelengths from 210-700 nm. Experimental action spectra were acquired for the isolated cation radicals and were found to closely match the theoretical spectra generated by time-dependent density functional theory (TD-DFT) calculations, which considered various functionals and basis sets. The results also suggested that the guanine, 9-methylguanine, and guanosine canonical structures were the predominant cation radical conformations in the gas-phase, and were in agreement with past infrared multiphoton photodissociation (IRMPD) action spectroscopy studies. The DNA nucleobase cation radical of thymine was also closely investigated using UVPD action spectroscopy in conjunction with other complementary methods. In this case, thymine cation radicals were generated via MS2-CID of their doubly-charged Cu(II)-complexes and were characterized via UVPD action spectroscopy, hydrogen-deuterium exchange experiments, ion-molecule reactions, and theoretical calculations. The experimental results suggested a mixture consisting chiefly of non-canonical thymine cation radical tautomers (77%), with the canonical isomer as a minor component (23%). Theoretical calculations predicting the low-energy isomers also supported the experimental results. Lastly, the peculiar discovery of gas-phase water splitting involving simple transition metal complexes is addressed. For decades, immense efforts have been directed at achieving catalytic water splitting using sophisticated water oxidation complexes and sunlight to generate carbon-neutral fuels. Here, a novel method utilizing transition metal complexes and near-UV light to split water into hydroxyl radical is explained. (2,2'-bipyridine)Metal-O+ ions (Metal = Cu, Ni, Co) were first produced by near-UV photodissociation of [(2,2'-bipyridine)Metal[superscript]IINO3]+ ions in the gas phase. Upon storage in an ion trap, the (2,2'-bipyridine)Metal-O+ ions spontaneously added water, and the newly-formed [(2,2'-bipyridine)Metal-O + H2O]+ complexes eliminated OH after subsequent near-UVPD (i.e. 260-340 nm) to achieve stoichiometric homolytic cleavage of gaseous water. Ion-molecule reactions, isotope-labeling experiments, and DFT calculations were further conducted to better characterize the reactions.
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mass Selected-ion Infrared Photodissociation Spectroscopy of Gas Phase Transition Metal-acetylene Complexes by : Timothy Brandon Ward
Download or read book Mass Selected-ion Infrared Photodissociation Spectroscopy of Gas Phase Transition Metal-acetylene Complexes written by Timothy Brandon Ward and published by . This book was released on 2018 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Alkali Metal Ions: Their Role for Life by : Astrid Sigel
Download or read book The Alkali Metal Ions: Their Role for Life written by Astrid Sigel and published by Springer. This book was released on 2016-02-09 with total page 663 pages. Available in PDF, EPUB and Kindle. Book excerpt: MILS-16 provides an up-to-date review of the impact of alkali metal ions on life. Their bioinorganic chemistry and analytical determination, the solid state structures of bio-ligand complexes and the properties of alkali metal ions in solution in the context of all kinds of biologically relevant ligands are covered, this includes proteins (enzymes) and nucleic acids (G-quadruplexes). Minerals containing sodium (Na+) and potassium (K+) are abundant in the Earth's crust, making Na+ and K+ easily available. In contrast, the alkali elements lithium (Li+), rubidium, and cesium are rare and the radioactive francium occurs only in traces. Since the intra- and extracellular, as well as the compartmental concentrations of Na+ and K+ differ significantly, homeostasis and active transport of these ions are important; this involves transporters/carriers and pore-forming ion channel proteins. Systems like Na+/K+-ATPases, H+/K+-ATPases or Na+/H+ antiporters are thoroughly discussed. The role of K+ in photosynthesis and the role of Na+ in charging the "battery of life" are pointed out. Also, the relationships between alkali metal ions and diseases (e.g., Parkinson or traumatic brain injury) are covered and the relevance of Li+ salts in medicine (pharmacology and mechanism) is reviewed. This and more is treated in an authoritative and timely manner in the 16 stimulating chapters of Volume 16, The Alkali Metal Ions: Their Role for Life, which are written by 44 internationally recognized experts from 12 nations. The impact of this vibrant research area is manifested in nearly 3000 references, over 30 tables and more than 150 illustrations (two thirds in color). MILS-16 also provides excellent information for teaching. Astrid Sigel, Helmut Sigel, and Roland K. O. Sigel have long-standing interests in Biological Inorganic Chemistry. Their research focuses on metal ion interactions with nucleotides and nucleic acids and on related topics. They edited previously 44 volumes in the series Metal Ions in Biological Systems.
Download or read book Oxide Surfaces written by and published by Elsevier. This book was released on 2001-05-21 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is a multi-author survey (in 15 chapters) of the current state of knowledge and recent developments in our understanding of oxide surfaces. The author list includes most of the acknowledged world experts in this field. The material covered includes fundamental theory and experimental studies of the geometrical, vibrational and electronic structure of such surfaces, but with a special emphasis on the chemical properties and associated reactivity. The main focus is on metal oxides but coverage extends from 'simple' rocksalt materials such as MgO through to complex transition metal oxides with different valencies.
Book Synopsis Characterization of Several Small Biologically Relevant Molecules by Infrared Multiple Photon Dissociation Spectroscopy and Electronic Structure Calculations by : Sabrina M. Martens
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).
Book Synopsis American Doctoral Dissertations by :
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2002 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
