We report femtosecond time-resolved measurements of the McLafferty rearrangement following the strong-field tunnel ionization of 2-pentanone, 4-methyl-2-pentanone, and 4,4-dimethyl-2-pentanone. The pump-probe-dependent yields of the McLafferty product ion are fit to a biexponential function with fast (∼100 fs) and slow (∼10 ps) time constants, the latter of which is faster for the latter two compounds. Following nearly instantaneous ionization, the fast time scale is associated with rotation of the molecule to a six-membered cyclic intermediate that facilitates transfer of the γ-hydrogen, while the ∼50-100 times longer time scale is associated with a π-bond rearrangement and bond cleavage between the α- and β-carbons to produce the enol cation. These experimental measurements are supported by molecular dynamics trajectories, which further confirm the time scale of this important stepwise reaction in mass spectrometry.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.jpclett.3c02102 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Developing and evaluating a gamified self-management application for inflammatory bowel disease using the ADDIE model and Sukr framework.
BMC Med Inform Decis Mak
January 2025
Medical Informatics Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, 13944-91388, Iran.
Background: The prevalence and chronic nature of Inflammatory Bowel Diseases (IBD) is a significant global concern. As the essential part of treatments approach, patient adherence to treatment protocols and self-management practices are crucial to = IBD management. Healthcare initiatives focused on chronic conditions are strongly needed to consider various aspects of gamification and how it can positively affect self-management.
View Article and Find Full Text PDFGender differences in acute and perceived stress, bullying, and academic motivation among nursing and midwifery students.
BMC Nurs
January 2025
Department of Nursing Sciences, College of Applied Medical Sciences, Shaqra University, Shaqra, Saudi Arabia.
Background: College-aged students are at risk for experiencing negative events that may influence their future health and life. Those negative events or stressors may vary in type and severity. Stress and bullying are prevalent among nursing students that may affect their academic motivation.
View Article and Find Full Text PDFA prospective, longitudinal, comparative analysis of the World Health Organization / International Committee of the Red Cross Basic Emergency Care Course on emergency medicine knowledge and confidence among recent medical school graduates.
Int J Emerg Med
January 2025
Department of Emergency Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Background: The Basic Emergency Care (BEC) course was created by the World Health Organization (WHO) in collaboration with the International Committee of the Red Cross (ICRC) and the International Federation for Emergency Medicine (IFEM) to train frontline providers in low-resource settings. This study aims to evaluate long-term retention and maintenance of emergency care knowledge and confidence among University of Nairobi School of Medicine graduates after completing the BEC course.
Methods: This longitudinal, prospective, comparative study was conducted with recent graduates of the University of Nairobi School of Medicine from October 2021 to May 2023.
Background: Elderly individuals living alone represent a vulnerable group with limited family support, making them more susceptible to mental health issues such as depression and anxiety. This study aims to construct a network model of depression and anxiety symptoms among older adults living alone, exploring the correlations and centrality of different symptoms. The goal is to identify core and bridging symptoms to inform clinical interventions.
View Article and Find Full Text PDFEfficacy of ultrasound guided erector spinae plane block compared to wound infiltration for postoperative analgesia following laparoscopic living donor nephrectomy: a double-blinded randomized controlled trial.
BMC Anesthesiol
January 2025
Department of Anaesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Background: Postoperative pain remains a significant problem in patients undergoing donor nephrectomy despite reduced tissue trauma following laparoscopic living donor nephrectomy (LLDN). Inadequately treated pain leads to physiological and psychological consequences, including chronic neuropathic pain.
Materials And Methods: This randomized controlled double-blinded trial was conducted in sixty-nine (n = 69) participants who underwent LLDN under general anesthesia.
Want 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!