The configurational stability of chlorophosphines is investigated. Several mechanisms involving chlorophosphine monomer, dimers, and adducts with HCl are evaluated by density functional theory calculations. The presence of HCl in the medium is found to catalyze the P-center chiral inversion at room temperature. The reaction involves a two-step mechanism with low transition states (10 kcal.mol-1) and a stabilized achiral intermediate (-2.6 kcal.mol-1). Further calculations and experiments on the halogen exchange with HBr corroborate this mechanism, with bromophosphines being formed instantaneously. Finally, to avoid the racemization, the borane is found to be a very promising protecting group for the configurational stability of the P-chirogenic chlorophosphines.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ic026128u | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Modification of Liposomal Properties by an Engineered Gemini Surfactant.
Langmuir
January 2025
Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, United States.
Lipid membranes form the primary structure of cell membranes and serve as configurable interfaces across numerous applications including biosensing technologies, antifungal treatments, and therapeutic platforms. Therefore, the modification of lipid membranes by additives has important consequences in both biological processes and practical applications. In this study, we investigated a nicotinic-acid-based gemini surfactant (NAGS) as a chemically tunable molecular additive for modulating the structure and phase behavior of liposomal membranes.
View Article and Find Full Text PDFEPR Characterization of the BlsE Substrate Radical Offers Insight into the Determinants of Reaction Outcome that Distinguish Radical SAM Dioldehydratases from Dehydrogenases.
J Am Chem Soc
January 2025
Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
A small but growing set of radical SAM (-adenosyl-l-methionine) enzymes catalyze the radical mediated dehydration or dehydrogenation of 1,2-diol substrates. In some cases, these activities can be interchanged via minor structural perturbations to the reacting components raising questions regarding the relative importance of hyperconjugation, proton circulation and leaving group stability in determining the reaction outcome. The present work describes trapping and electron paramagnetic resonance (EPR) characterization of an α-hydroxyalkyl radical intermediate during dehydration and dehydrogenation of cytosylglucuronic acid and its derivatives catalyzed by the radical SAM enzyme BlsE and its Glu189Ala mutant from the blasticidin S biosynthetic pathway.
View Article and Find Full Text PDFDevelopment of Novel Oral Delivery Systems Using Additive Manufacturing Technologies to Overcome Biopharmaceutical Challenges for Future Targeted Drug Delivery.
Pharmaceutics
December 2024
Department of Biopharmaceutics and Pharmaceutical Technology, Institute of Pharmacy, University of Greifswald, Felix-Hausdorff-Strasse 3, 17489 Greifswald, Germany.
The development of targeted drug delivery systems for active pharmaceutical ingredients with narrow absorption windows is crucial for improving their bioavailability. This study proposes a novel 3D-printed expandable drug delivery system designed to precisely administer drugs to the upper small intestine, where absorption is most efficient. The aim was to design, prototype, and evaluate the system's functionality for organ retention and targeted drug release.
View Article and Find Full Text PDFAn Over-Actuated Hexacopter Tilt-Rotor UAV Prototype for Agriculture of Precision: Modeling and Control.
Sensors (Basel)
January 2025
Faculty of Minas Gerais (FAMINAS), Muriaé 36888-233, Brazil.
This paper focuses on the modeling, control, and simulation of an over-actuated hexacopter tilt-rotor (HTR). This configuration implies that two of the six actuators are independently tilted using servomotors, which provide high maneuverability and reliability. This approach is predicted to maintain zero pitch throughout the trajectory and is expected to improve the aircraft's steering accuracy.
View Article and Find Full Text PDFStructural, Electronic, and Magnetic Properties of Neutral Borometallic Molecular Wheel Clusters.
Materials (Basel)
January 2025
Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093 Warsaw, Poland.
Atomic clusters exhibit properties that fall between those found for individual atoms and bulk solids. Small boron clusters exhibit planar and quasiplanar structures, which are novel materials envisioned to serve as a platform for designing nanodevices and materials with unique physical and chemical properties. Through past research advancements, experimentalists demonstrated the successful incorporation of transition metals within planar boron rings.
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!