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Author

Bruce S. Ault

Other affiliations: University of Virginia
Bio: Bruce S. Ault is an academic researcher from University of Cincinnati. The author has contributed to research in topics: Matrix isolation & Infrared spectroscopy. The author has an hindex of 30, co-authored 269 publications receiving 4190 citations. Previous affiliations of Bruce S. Ault include University of Virginia.


Papers
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TL;DR: In this article, the matrix isolation technique has been employed to isolate several intermediates, in sequence, in the oxidation of CH3OH by CrCl2O2, leading to the production of HCl and ClCrO2OCH3.
Abstract: The matrix isolation technique has been employed to isolate several intermediates, in sequence, in the oxidation of CH3OH by CrCl2O2. Consistent with previous theoretical calculations, a hydrogen-bonded complex formed initially after twin jet deposition and was enhanced by matrix annealing to 33 K. This complex was photodestroyed by Hg arc irradiation with λ < 500 nm, and led to the production of HCl and ClCrO2OCH3. These species were also produced by room temperature reaction of the two precursors in a flow system followed by rapid matrix trapping. Heating the flow reaction zone above 150 °C led to destruction of ClCrO2OCH3, and production of CH2O and HCl. Above 250 °C bands due to CH2O were destroyed and bands due to CO and CO2 grew in. High-level density functional calculations (B3LYP/6-311G*) were carried out to identify potential intermediates in this system and to provide theoretical vibrational spectra for comparison to experiment.

38 citations

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TL;DR: In this paper, the 1:1 hydrogen-bonded complex between H2O2 and (CH3)2O was characterized using matrix isolation infrared spectroscopy and MP2/6-31+G(d,p) calculations.
Abstract: Matrix isolation infrared spectroscopy has been combined with MP2/6-31+G(d,p) calculations to characterize the 1:1 hydrogen-bonded complex between H2O2 and (CH3)2O. The O−H stretching mode was observed to red shift 234 cm-1 upon hydrogen bond formation, while a 45 cm-1 blue shift was noted for the O−O−H bending mode of the H2O2 subunit in the complex. These values compare well to the computed shifts of −293 and +20 cm-1, respectively. The perturbations to the vibrational modes of the two subunits in the HOOH:O(CH3)2 complex are substantially larger than the perturbations reported previously for the analogous HOH:O(CH3)2 complex, suggesting that H2O2 is a better proton donor for hydrogen bonding than H2O. In contrast, band shifts in HOOH:O(CH3)2 are much less than observed for FH:O(CH3)2 and ClH:O(CH3)2.

37 citations

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TL;DR: In this paper, a composes d'addition formes entre acides and bases of Lewis, par exemple SiF 4 •NH 3, are presented.
Abstract: Cas particulier des composes d'addition formes entre acides et bases de Lewis, par exemple SiF 4 •NH 3

37 citations

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TL;DR: In this paper, the magnesium-ozone reaction has been studied by condensing the reagents with nitrogen at 14 K. Isotopic substitution with 26Mg, 16,18O3, and 18O3 has identified infrared absorptions due to two different Mg+O−3 species, MgO2 and Mg
Abstract: The magnesium–ozone reaction has been studied by condensing the reagents with nitrogen at 14 K. Isotopic substitution with 26Mg, 16,18O3, and 18O3 has identified infrared absorptions due to two different Mg+O−3 species, MgO2 and MgO. Six isotopic MgO molecules support this infrared detection of MgO which shows a blue matrix shift. Analogous argon matrix reactions produced only Mg+O−3 and two isomeric MgO3 species.

35 citations

Journal ArticleDOI
TL;DR: In this paper, a matrix isolation technique combined with infrared spectroscopy was employed to isolate and characterize hydrogen-bonded complexes between 1-alkynes and a series of second-and third-row bases.
Abstract: The matrix isolation technique, combined with infrared spectroscopy, has been employed to isolate and characterize hydrogen-bonded complexes between 1-alkynes and a series of second- and third-row bases. Distinct evidence for hydrogen bond formation was observed in each case, with a characteristic shift to lower energies of the alkynic C-H stretching mode. These shifts ranged from 25 to 150 cm{sup {minus}1}, with complexes of CF{sub 3}CCH consistently having the largest shifts. For a given acid, the magnitude of the shift of the C-H stretching vibration, as a function of the base, varied in the order P(CH{sub 3}){sub 3} > (CH{sub 3}){sub 2}S > (CH{sub 3}){sub 2}Se > PH{sub 3} > H{sub 2}S > AsH{sub 3}. For the very weak bases H{sub 2}S and AsH{sub 3}, a second complex in which the alkyne serves as a proton acceptor and H{sub 2}S or AsH{sub 3} serves as the proton donor was also detected. The shifts observed in this study were significantly smaller than observed in previous studies and have been rationalized in terms of hard/soft acid/base theory.

35 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors survey the local density functional formalism and some of its applications and discuss the reasons for the successes and failures of the local-density approximation and some modifications.
Abstract: A scheme that reduces the calculations of ground-state properties of systems of interacting particles exactly to the solution of single-particle Hartree-type equations has obvious advantages. It is not surprising, then, that the density functional formalism, which provides a way of doing this, has received much attention in the past two decades. The quality of the energy surfaces calculated using a simple local-density approximation for exchange and correlation exceeds by far the original expectations. In this work, the authors survey the formalism and some of its applications (in particular to atoms and small molecules) and discuss the reasons for the successes and failures of the local-density approximation and some of its modifications.

3,285 citations

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TL;DR: The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.
Abstract: The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

2,582 citations

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TL;DR: In this Review, the fundamental characteristics of azide chemistry and current developments are presented and the focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles.
Abstract: Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aube rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.

1,766 citations

Journal ArticleDOI
TL;DR: The review covers the knowledge on photoremovable protecting groups and includes all relevant chromophores studied in the time period of 2000–2012 and the most relevant earlier works are discussed.
Abstract: The review covers the knowledge on photoremovable protecting groups and includes all relevant chromophores studied in the time period of 2000–2012; the most relevant earlier works are also discussed.

1,274 citations