The gas-phase acidities of the vinyl hydrogens of cis- and trans-2-butene were measured by the silane kinetic method in a Fourier-transform ion cyclotron resonance spectrometer. The acidities of ethene and the secondary vinyl hydrogen of propene were measured by the same method. The method was calibrated using the known acidities of methane and benzene. The vinyl hydrogens of trans-2-butene are more acidic than the vinyl hydrogens of cis-2-butene by 4.5 kcal/mol; the acidities of ethene and the secondary vinyl hydrogen of propene are between those of the two butenes. The acidity of cis-2-butene is 409 +/- 2 kcal/mol, and the acidity of trans-2-butene is 405 +/- 2 kcal/mol. Density functional theory calculations are in good agreement with the experiments. The results are discussed in terms of steric interactions, polarizabilities, dipole-dipole interactions, and charge-dipole interactions.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jp0666075 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Microplastics and Dechlorane Plus co-exposure amplifies their impacts on soybean plant.
Environ Pollut
January 2025
Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China. Electronic address:
The co-existence of microplastics (MPs) and organic pollutants on agricultural ecosystems pose potential implications for both food safety and environmental integrity. The combined effects of MPs with Dechlorane Plus (DP), a newly listed banned flame retardant, remain unknown. This study explores the biological responses of soybean plants to exposure from polyethylene (PE) and polyvinyl chloride (PVC) MPs and DP.
View Article and Find Full Text PDFUntangling the Efficient Boron-Initialized Hydroxyl-Terminated Polybutadiene Combustion for High Energetic Solid Propulsion Systems.
J Phys Chem A
December 2024
Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States.
Highly energetic boron (B) particles embedded in hydroxyl-terminated polybutadiene (HTPB) thermosetting polymers represent stable solid-state fuel. Laser-heating of levitated B/HTPB and pure HTPB particles in a controlled atmosphere revealed spontaneous ignition of B/HTPB in air, allowing for examination of the exclusive roles of boron. These ignition events are probed via simultaneous spectroscopic diagnostics: Raman and infrared spectroscopy, temporally resolved high-speed optical and infrared cameras, and ultraviolet-visible (UV-vis) spectroscopy.
View Article and Find Full Text PDFOrvinol-based opioid receptor antagonist fluorinated at C(20)-pharmacophore.
Eur J Med Chem
December 2024
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 28, bld. 1, Moscow, 119334, Russia. Electronic address:
Thevinols and their 3-O-demethylated relatives, orvinols, are derivatives of the Diels-Alder adduct of natural alkaloid thebaine with methyl vinyl ketone. Taken together, thevinols and orvinols constitute an important family of opioid receptor (OR) ligands playing an important role in both the OR mediated antinociception and OR antagonism. Herein, we disclose for the first time the antagonist activity of the N-allyl substituted orvinol derivative fluorinated within the pharmacophore associated with C(20) and its surrounding.
View Article and Find Full Text PDFA Shape-Memory and Durable Transparent Polyacrylate Film Integrated by Soft-Rigid Chains.
Chemistry
December 2024
School of Chemical Engineering, Changchun University of Technology, Changchun, 130012, China.
Flexible film in display requires multi-functional integration, such as stretchability, flexibility, abrasion resistance, transparency, and shape memory. In this paper, a reasonable design strategy of flexible polyacrylate (PA) film with high transparency, shape memory, excellent abrasion resistance and foldability is presented. The PA films are prepared by free radical polymerization of vinyl-terminated polyurethane (PU) prepolymer as a cross-linking agent and acrylate monomers in ultraviolet (UV) light.
View Article and Find Full Text PDFSimple Preparation and Bone Regeneration Effects of Poly(vinyl alcohol)-Resveratrol Self-Cross-Linked Hydrogels.
ACS Omega
December 2024
Department of Radiotherapy Oncology, Changzhou No.2 People's Hospital, Nanjing Medical University, Changzhou 213003, China.
Hydrogels have broad application prospects in bone repair. Pure poly(vinyl alcohol) (PVA) hydrogels have limited applications because of their low hardness and poor mechanical properties. This study found that resveratrol (Res) and PVA self-assembled and cross-linked through the formation of strong hydrogen bonds after freeze-thawing, forming an easily available PVA-Res supramolecular hydrogel through a green process.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!