Using high-pressure infrared methods, we have investigated close interactions of charge-enhanced C-H-O type in ionic liquid∕dimethyl sulfoxide (DMSO) mixtures. The solvation and association of the 1-butyl-3-methylimidazolium tetrafluoroborate (BMI(+)BF(4)(-)) and 1-butyl-2,3-dimethylimidazolium tetrafluoroborate (BMM(+)BF(4)(-)) in DMSO-d(6) were examined by analysis of C-H spectral features. Based on our concentration-dependent results, the imidazolium C-H groups are more sensitive sites for C-H-O than the alkyl C-H groups and the dominant imidazolium C-H species in dilute ionic liquid∕DMSO-d(6) should be assigned to the isolated (or dissociated) structures. As the dilute mixtures were compressed by high pressures, the loss in intensity of the bands attributed to the isolated structures was observed. In other words, high pressure can be used to perturb the association-dissociation equilibrium in the polar region. This result is remarkably different from what is revealed for the imidazolium C-H in the BMM(+)BF(4)(-)∕D(2)O mixtures. DFT-calculations are in agreement with our experimental results indicating that C(4)-H-O and C(5)-H-O interactions seem to play non-negligible roles for BMM(+)BF(4)(-)∕DMSO mixtures.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/1.3526485 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Remote -selective C-H bromination of arenes using a recyclable Ru-based aminopropyl bifunctional PMO with robust imidazolium bridges.
Dalton Trans
January 2025
DICATECh, Politecnico di Bari, Bari, I-70125, Italy.
This systematic study delves into the synthesis and characterization of robust bi-functional aminopropyl-tagged periodic mesoporous organosilica with a high loading of small imidazolium bridges in its framework (PrNH@R-PMO-IL, ∼2 mmol g of IL). The materials proved to be a reliable and enduring support for the immobilization of Ru species, demonstrating strong performance and excellent selectivity in the -bromination of various derivatives of 2-phenylpyridine compounds and other heterocycles, showcasing its effectiveness and robust nature. The synthesized materials were thoroughly characterized to determine their structural properties, such as pore size distribution, loading of organic groups, and surface area, using various analytical techniques.
View Article and Find Full Text PDFFacile and Regioselective Deuteration of C2-Alkylated Imidazolium Salts in the Presence of Cesium Carbonate.
Chemistry
December 2024
Laboratory of Catalysis, MolSys Research Unit, Université de Liège, Institut de Chimie Organique (B6a), Allée du six Août 13, 4000, Liège, Belgium.
Thirteen imidazolium iodides bearing benzyl, mesityl, or 2,6-diisopropylphenyl substituents on their nitrogen atoms, and C-C alkyl chains on their C2 carbon atom were readily deuterated with DO as a cheap and non-toxic deuterium source in the presence of CsCO, a weak, innocuous, inorganic base. The isotopic exchange proceeded quickly and efficiently under mild, aerobic conditions to afford a range of aNHC and NHO precursors regioselectively labeled on their C2α exocyclic position and/or C4=C5 heterocyclic backbone. A "carbene-free" mechanism was postulated, in which the carbonate anion acts as a catalyst to activate an exocyclic, acidic C-H bond and ease a deuterium transfer from DO to the imidazolium salt in a concerted fashion.
View Article and Find Full Text PDFMagnetic Isolation of the Linear Trinuclear Anion in [Cu(Him)] {Cu(Him)[Cu(μ-EDTA)(Him)]}·6HO (1) as the Novel Imidazolium(+) Salt (Him)[Cu(Him){(µ-EDTA)Cu(Him)}]·2HO (2)-A Comparative Look to Their Crystal Structures, Thermal, Spectral and Magnetic Properties and DFT Calculations.
Int J Mol Sci
December 2024
Department of Inorganic Chemistry, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain.
Article Synopsis
- The study focuses on synthesizing and analyzing the structure of a compound featuring imidazolium ions as countercations, based on previously known crystal structures.
- Various techniques, including thermal stability assessments and spectral analysis, reveal differences in how the pentadentate chelator µ-EDTA interacts with copper centers in two different compounds.
- The findings highlight the impact of imidazolium ions on the magnetic properties and stability of the structures, supported by DFT calculations showing significant hydrogen bonding and stacking interactions within the trinuclear anion.
Uncovering diverse reactivity of NHCs with diazoalkane: C-H activation, C[double bond, length as m-dash]C bond formation, and access to N-heterocyclic methylenehydrazine.
Chem Sci
October 2024
Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory Dr Homi Bhabha Road, Pashan Pune 411008 India
N-heterocyclic carbenes (NHCs) have attracted significant attention due to their strong σ-donating capabilities, as well as their transition-metal-like reactivity towards small molecules. However, their interaction with diazoalkanes remains understudied. In this manuscript, we explore the reactivity of a series of stable carbenes, encompassing a wide range of electronic properties, with MeSiCHN.
View Article and Find Full Text PDFThe interplay of mutagenesis and ecDNA shapes urothelial cancer evolution.
Nature
November 2024
Department of Medicine, Weill Cornell Medicine, New York, NY, USA.
Article Synopsis
- Advanced urothelial cancer displays significant genetic diversity and involves complex interactions between internal and external mutagens, which contributes to its deadly nature.
- The study revealed that APOBEC3-induced mutations occur early during tumor development, while chemotherapy leads to a surge of later mutations, with both processes affecting the structure of extrachromosomal DNA.
- Findings emphasized the role of circular ecDNA in the development of treatment resistance, specifically through CCND1 amplifications, highlighting key mechanisms that can inform future cancer therapies.
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!