We investigated the rotational spectrum of 2,5-dimethylfluorobenzene containing coupled large amplitude motions of two methyl groups in the frequency range from 2 to 26.5 GHz using a pulsed molecular jet Fourier transform microwave spectrometer. The internal rotation of two inequivalent methyl groups with low torsional barriers (around 16 and 226 cm-1) causes splittings of all rotational transitions into quintets with separations of up to hundreds of MHz between the torsional components. Spectral analysis and modeling of the observed splittings were performed using the programs XIAM and BELGI-Cs-2Tops, whereby the latter achieved measurement accuracy. The methyl internal rotation can be used to examine the electronic and steric environments around the methyl group because they affect the methyl torsional barrier. Electronic properties play a particularly important role in aromatic molecules in the presence of a π-conjugated double bond system. The experimental results were compared with those of quantum chemistry. Benchmark calculations resulted in the conclusion that the B3LYP-D3BJ/6-311++G(d,p) level of theory can be recommended for predicting rotational constants to guide the microwave spectral assignment of dimethylfluorobenzenes in particular and toluene derivatives in general.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1063/5.0185005 | DOI Listing |
BMC Nurs
January 2025
College of Nursing Science, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
Background: A hospital nurse's clinical decision-making ability is an important core competency that identifies and solves patient problems in nursing practice. This study aimed to develop a Korean clinical decision-making scale for hospital nurses, and verify its validity and reliability.
Methods: A methodological design that develops a scale was used.
BMC Musculoskelet Disord
January 2025
Department of Pediatric Orthopaedics, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Rd, Minhang District, Shanghai, 201102, China.
Purpose: Ollier's disease (multiple enchondromatosis) can cause severe lower limb length discrepancy and deformity in children. Osteotomy and limb lengthening with external fixation can correct the lower extremity deformity. There may be lesions in the osteotomy part (OP), and the internal fixation part of the external fixation(FP).
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemistry, KAIST, Daejeon, Republic of Korea.
Despite its profound significance, the molecular structural changes near the transition state, driven by the vibronic coupling, have remained largely unexplored, leaving a crucial aspect of chemical reactions shrouded in uncertainty. Herein, the dynamical behavior of the reactive flux on the verge of chemical bond breakage was revealed through the spectroscopic characterization of a large amplitude vibrational motion. Highly excited internal rotor states of S methylamine (CHND) report on the structural change as the molecule approaches the transition state, indicating that the quasi-free internal rotation is strongly coupled to the reaction coordinate as their energies near the maximum of the reaction barrier for the N-D chemical bond predissociation.
View Article and Find Full Text PDFJ Knee Surg
January 2025
Lenox Hill Hospital Department of Orthopedic Surgery, Northwell Health, New York, United States.
Patellar instability following total knee arthroplasty (TKA) is a rare, yet serious complication, potentially requiring revision surgery or resulting in chronic dysfunction. When encountered, it is paramount to understand the etiologies, diagnostic approaches, treatment options, and outcomes of the selected treatment. The most common cause of patella instability is improper positioning of components, leading to lateral maltracking of the patella.
View Article and Find Full Text PDFEur Heart J Case Rep
January 2025
Department of Cardiovascular Medicine, Sendai Kousei Hospital, 1-20 Tsutsumidori-amamiya, Aoba Ward, Sendai, Miyagi 9810914, Japan.
Background: Transcatheter edge-to-edge mitral valve repair (M-TEER) using the MitraClip system is primarily performed using the transfemoral approach. However, when this approach is not feasible, the transjugular approach can be used as an alternative.
Case Summary: A 57-year-old man presented with heart failure and persistent New York Heart Association class IV symptoms, refractory to guideline-directed medical therapy, intravenous therapy, and intra-aortic balloon pumping.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!