skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Astatine partitioning between nitric acid and conventional solvents: indication of covalency in ketone complexation of AtO +
Title: Astatine partitioning between nitric acid and conventional solvents: indication of covalency in ketone complexation of AtO +
Astatine-211 has been produced at Texas A&M University on the K150 cyclotron, with a yield of 890 ± 80 MBq through the 209 Bi(α,2n) 211 At reaction via an 8 h bombardment with a beam current of 4–8 μA and an α-particle beam energy of 28.8 MeV. The target was then dissolved in HNO 3 and the extraction of 211 At was investigated into a variety of organic solvents in 1–3 M HNO 3 . Extraction of 211 At with distribution ratios as high as 11.3 ± 0.6, 12.3 ± 0.8, 42.2 ± 2.2, 69 ± 4, and 95 ± 6 were observed for diisopropyl ether, 1-decanol, 1-octanol, 3-octanone, and methyl isobutyl ketone, respectively, while the distribution ratios for 207 Bi were ≤0.05 in all cases. The extraction of 211 At into both methyl isobutyl ketone and 3-octanone showed a strong, linear dependence on the HNO 3 initial aqueous concentration and better extraction than other solvents. DFT calculations show stronger binding between the carbonyl oxygen of the ketone and the At metal center.  more » « less
Award ID(s):
1664866
PAR ID:
10252431
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Chemical Communications
Volume:
56
Issue:
63
ISSN:
1359-7345
Page Range / eLocation ID:
9004 to 9007
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. (, Limnology and Oceanography: Methods)
    Abstract 210Bi (t1/2: 5.01 d)—the daughter of210Pb and parent of210Po—has rarely been measured in aquatic systems, and its behavior in the water column is poorly understood. In this article, I present a method for quickly measuring210Pb,210Bi, and210Po in aquatic samples, where (1)210Bi and210Po are scavenged onto an anion solid‐phase extraction disk within 15 min of pretreating the sample; (2) beta decay of210Bi is counted on the disk immediately thereafter; (3)210Po is subsequently removed from the disk and redeposited on a copper plate for α‐spectroscopy; and (4)210Pb is determined via the ingrowth of210Bi. I present decay‐corrected calculations for total, dissolved, and particle‐bound fractions of each nuclide and conclude with an analysis of210Pb,210Bi, and210Po activities in rain,dreissenid(quagga) mussels, and water samples from the Milwaukee Inner Harbor in Lake Michigan. Results show that the loss of lead on the anion solid‐phase extraction disks was negligible (0.2% ± 2.1%; ± 1 SD,n= 4), and the sorption of bismuth was complete (99% ± 2%; ± 1 SD,n= 16). Relative mean absolute deviations of duplicate sample analyses of lake water were 2.4% ± 1.9% for210Pb (geometric mean of total sample activity: 3.0 disintegrations per minute [dpm],n= 6), 7.7% ± 5.8% for210Bi (geometric mean of total sample activity: 2.6 dpm,n= 8), and 2.7% ± 1.7% for210Po (geometric mean of total sample activity: 1.4 dpm,n= 8). 
    more » « less
  2. ; (, Environmental Science: Atmospheres)
    Despite their atmospheric abundance, heterogeneous and multiphase reactions of carbonyl compounds are poorly understood. In this study, we investigate the surface adsorption and surface chemistry of methyl ethyl ketone (MEK), the second most abundant ketone in the atmosphere, with several mineral oxide surfaces including SiO 2 , α-Fe 2 O 3 and TiO 2 . In particular, the chemistry of MEK with these common components of mineral dust, under both dry and high relative humidity (RH%) conditions, has been investigated. Furthermore, reactions of adsorbed MEK with gas-phase NO 2 were also examined. We show that MEK molecularly and reversibly adsorbs on SiO 2 whereas irreversible adsorption occurs on both α-Fe 2 O 3 and TiO 2 surfaces, followed by the formation of higher molar mass species resulting from dimerization and oligomerization reactions. Isotope labeling experiments confirmed the incorporation of H atoms from surface hydroxyl groups and strongly adsorbed water into these oligomer products. Most interesting is that at 80% RH, oligomer formation on α-Fe 2 O 3 shifts toward a higher relative abundance of MEK tetramer relative to the dimer while on TiO 2 there was no change in product distribution. In the presence of gas-phase NO 2 , MEK undergoes degradation to formaldehyde and acetaldehyde, followed by the formation of aldol condensation products of these aldehydes on the α-Fe 2 O 3 surface. Overall, this study provides mechanistic insights on mineralogy-specific heterogeneous chemistry of a prevalent and atmospherically abundant ketone. 
    more » « less
  3. ; ; ; ; ; ; (, Physics and Chemistry of Liquids)
    Experimental water-to-methyl isobutyl ketone partition coefficientshave been determined for 27 different organic solutes based on gaschromatographic measurements. Updated Abraham model correlationswere determined for describing solute transfer into methyl isobutylketone by combining the measured partition coefficient data deter-mined in the present study with published experimental values takenfrom chemical and engineering literature. One hundred nineteen com-pounds were used in determining the revised Abraham model correla-tions. After calculations, the revised mathematical correlations werefound to match the experimental data to within an overall averagestandard deviation of 0.21 log units. 
    more » « less
  4. ; ; ; (, Angewandte Chemie International Edition)
    Abstract A novel, selective and high‐yielding palladium‐catalyzed carbonylative arylation of a variety of weakly acidic (pKa25–35 in DMSO) benzylic and heterobenzylic C(sp3)−H bonds with aryl bromides has been achieved. This system is applicable to a range of pro‐nucleophiles for access to sterically and electronically diverse α‐aryl or α,α‐diaryl ketones, which are ubiquitous substructures in biologically active compounds. The Josiphos SL‐J001‐1‐based palladium catalyst was identified as the most efficient and selective, enabling carbonylative arylation with aryl bromides under 1 atm CO to provide the ketone products without the formation of direct coupling byproducts. Additionally, (Josiphos)Pd(CO)2was identified as the catalyst resting state. A kinetic study suggests that the oxidative addition of aryl bromides is the turnover‐limiting step. Key catalytic intermediates were also isolated. 
    more » « less
  5. ; ; (, The Journal of Physical Chemistry B)
    This study investigates Marangoni effect-induced structural changes in spin-coated polymer nanocomposite (PNC) films composed of poly(methyl methacrylate)-grafted silica nanoparticles (NPs) and poly(styrene-ran-acrylonitrile). Films cast from methyl isobutyl ketone (MIBK) solvent exhibit distinct hexagonal honeycomb cells with thickness gradients driven by surface tension variations. Atomic force microscopy reveals protruded ridges and junctions at cell intersections, where NP concentration is the highest. Upon annealing at 155 degrees C, NPs segregate to the surface due to their lower surface energy, and the initially protruding features flatten and eventually form depressed channels while maintaining higher NP density than surrounding areas. Time-of-flight secondary ion mass spectrometry corroborated these findings, highlighting enhanced surface segregation of NPs in MIBK films. These defects can be eliminated using methyl isoamyl ketone (MIAK) as a solvent that produces homogeneous films of uniform thickness. This study highlights the impact of the Marangoni effect on the microstructure and surface properties of PNC films, providing insights for enhancing film quality and performance. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email