3,088 research outputs found
INFRARED SPECTRA OF GUEST MOLECULES IN CRYSTALLINE CLATHRATE HYDRATE FILMS
No full text J. E. Bertie and J. P. Devlin, J. Chem. Phys. 78. 6340 (1983). H. H. Richardson, P. J. Wooldridge and J. P. Devlin, J. Chem. Phys., 83, 4387 (1985)Author Institution: Department of Chemistry, Oklahoma State UniversityThe guest molecules in a clathrate hydrate are isolated in well-defined cages. Such systems were difficult to study spectroscopically prior to the demonstration that crystaline films of the clathrate hydrates of polar molecules can be readily deposited from the vapor . Recently, as part of a study of the mechanism of the growth of ice-like crystals at low temperatures, infrared spectra of several caged molecules have been measured. The spectra are marked by evidence of dynamical coupling between neighbour guest molecules, Evans holes (i.e., Fano antiresonances) caused by the interaction of guest and host vibrational states, and sharp variations with temperature that reflect the orientational dynamics of the engaged molecules
Determination of absolute configuration using vibrational circular dichroism spectroscopy: Phenyl glycidic acid derivatives obtained via asymmetric epoxidation using oxone and a keto bile acid
No full textThe (+)-enantiomers of the o-Br, m-F and p-CH3 derivatives of trans phenyl glycidic acid have been obtained from the
corresponding trans cinnamic acid derivatives using Oxone and the tri-keto bile acid dehydrocholic acid. Vibrational circular dichroism
(VCD) spectroscopy of their methyl esters has been used to determine their absolute configurations. In each case, the absolute
configurations of both methyl ester and parent acid were shown to be (2S,3R)-(+)/(2R,3S)-()
The Promotion Exams
No full text Mr. Devlin is author of Police Procedure, Administration and Organization </jats:p
Determination of Absolute Configuration Using Ab Initio Calculation of Optical Rotation
No full textAb initio Density Functional Theory (DFT) calculations of transparent
spectral region, discrete frequency specific rotations were used to assign the absolute
configurations (ACs) of: 1, 2H-naphtho[1,8-bc]thiophene 1-oxide; 2, m-F-phenyl glycidic
acid methyl ester; 3, o-Br-phenyl glycidic acid methyl ester; 4, p-CH3-phenyl glycidic
acid methyl ester; 5, 2-(1-hydroxyethyl)-chromen-4-one; and 6, 6-Br-2-(1-hydroxyethyl)-
chromen-4-one. The ACs of 5 and 6 were previously determined via X-ray crystallography
to be: 5, R(−)/S(+); 6, R(+)/S(−). The ACs obtained using []D are the same for
both 5 and 6: R(+)/S(−). We conclude that the previously reported AC of 5 is incorrec
The determination of absolute configuration using vibrational circular dichroism spectroscopy: chiral substituted tiepanes
No full text
Many hands make light work
No full textThe responses of plants to the light environment have fascinated biologists for well over 100 years (Briggs, 2006). Early studies in photomorphogenesis focused necessarily on morphological aspects of plant responses; germination, seedling establishment, plant architecture, and flowering time are all regulated by light. More recently, and particularly with the advent of the genetic model Arabidopsis thaliana, the focus has shifted to understanding plant responses at the molecular level. Understanding and genetically manipulating these processes may provide the subtle control of plant growth that will permit successful alteration of these traits for agricultural benefit. This Focus Section, based on the Photomorphogenesis session at this year's Society for Experimental Biology annual conference, contains reviews directed at both the progress in understanding the molecular basis of light-signalling pathways and how to translate this information for agricultural gain
The Interaction of HCl and Crystalline Ice Clusters at Cryogenic Temperatures: Evidence of the Molecular Complex
No full text1. Lance Delzeit, Brad Rowland, and J. Paul Devlin; J. Phys. Chem. 97 10312 (1993). 2. B. S. Ault and G. C. Pimentel; J. Phys. Chem. 77 57 (1973). 3. A. Schriver, et. al.; J. Phys. Chem. 87 2095 (1977). 4. G. Kroes and D. C. Clary; J. Phys. Chem. 96 7079 (1992). 5. Brad Rowland, Mark Fisher, and J. Paul Devlin; J. Chem. Phys. 95 1378 (1991).Author Institution: Oklahoma State University, Stillwater, OK 74078The addition of HCl to the surface of crystalline ice clusters at cryogenic temperatures produces spectroscopic changes which can be related to the formation of the hydronium ion and the HCl acting as a molecular adsorbate. The hydronium ion is identified from its IR active modes below . Evidence for the HCl acting as a molecular adsorbate is its effect on the dangling-hydrogen (d-H) mode and the appearance of a band. Analogous spectra for with the and the show two bands relative to the one band in the region due to the interaction. The single band in the HCl system is attributed to the near overlap of the bands due to the molecular and ionic interaction of the HCl and . Reference to matrix and computational will show the plausibility of the presence of the molecular complex. Shifting of the d-H band is a common effect for molecularly adsorbed species on the surface of The shifting of the d-H to a position yet unobserved for common adsorbates gives strong evidence of the HCl acting as a molecular adsorbate
CRYSTAL TO GLASS TRANSFORMATIONS IN SIMPLE SALT SYSTEMS
No full textG. Pollard, N. Smyrl, and J. P. Devlin, J. Phys. Chem. 76, 1826 (1972).Author Institution: Department of Chemistry, Oklahoma State UniversityIt has been shown that the glass phase of many simple salts (nitrates, chlorates, etc.) can be formed by condensing the molten salt vapors at low Admission of proportionate quantities of water vapor during the deposition of vapors permits formation of glassy solutions which crystallize at , forming a crystalline hydrate. The warming of the crystal hydrate in vacuo results in a loss of water at with the formation of the anhydrous glass, which eventually crystallizes to the stable anhydrous salt at . Spectra that are representative of the phases involved, and which provide evidence for the unusual crystal-to-glass transformation will be discussed
Determination of the Absolute Configuration of a Chiral Oxadiazol-3-one Calcium Channel Blocker, Resolved by Using Chiral Chromatography, via Concerted Density Functional Theory Calculations of Its Vibrational Circular Dichroism, Electronic Circular Dichroism, and Optical Rotation.
No full textThe chiral oxadiazol-3-one 2 has recently been shown to exhibit myocardial calcium entry channel blocking activity, substantially higher than that of diltiazem. To determine the enantioselectivity of this activity, the enantiomers of 2 have been resolved using chiral chromatography. The absolute configuration (AC) of 2 has been determined by comparison of density functional theory (DFT) calculations of its vibrational circular dichroism (VCD) spectrum, electronic circular dichroism (ECD) spectrum, and optical rotation (OR) to experimental VCD, ECD, and OR data. All three chiroptical properties yield identical ACs; the AC of 2 is unambiguously determined to be S(+)/R(-)
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