We explore the structures of [Ti(CO) ] cluster anions using infrared photodissociation spectroscopy and quantum chemistry calculations. The existence of spectral signatures of metal carbonyl CO stretching modes shows that insertion of titanium atoms into C-O bonds represents an important reaction during the formation of these clusters. In addition to carbonyl groups, the infrared spectra show that the titanium center is coordinated to oxalato, carbonato, and oxo ligands, which form along with the metal carbonyls. The presence of a metal oxalato ligand promotes C-O bond insertion in these systems. These results highlight the affinity of titanium for C-O bond insertion processes.
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http://dx.doi.org/10.1021/acs.jpca.8b01843 | DOI Listing |
Molecules
January 2025
School of Chemistry and Materials Engineering, Huainan Normal University, Huainan 232038, China.
Efficient access to pyranoisoquinoline derivatives via rhodium-catalyzed double C-H functionalization of phenyl oxadiazoles and diazo compounds has been developed. Two C-C bonds and one C-O and C-N bond formation was realized by this tandem reaction, along with the formation of two heterocycles, affording diversified pyran-fused isoquinolines in moderate to good yields with broad functional group tolerance under mild reaction conditions.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Wisconsin─Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Aryl triflates make up a class of aryl electrophiles that are available in a single step from the corresponding phenol. Despite the known reactivity of nickel complexes for aryl C-O bond activation of phenol derivatives, nickel-catalyzed cross-electrophile coupling using aryl triflates has proven challenging. Herein, we report a method to form C(sp)-C(sp) bonds by coupling aryl triflates with alkyl bromides and chlorides using phenanthroline (phen) or pyridine-2,6-bis(-cyanocarboxamidine) (PyBCam)-ligated nickel catalysts.
View Article and Find Full Text PDFInt J Cosmet Sci
January 2025
Department of Engineering Science, Osaka Electro-Communication University, Neyagawa, Japan.
Objective: This study aimed to identify structural changes in age-related curved hair (referred to as "YUGAMI" hair in Japanese) induced by cyclical extension using infrared (IR) spectroscopy coupled with chemometrics, such as multivariate curve resolution (MCR) and two-dimensional correlation spectroscopy (2DCOS).
Methods: The hair fibres were stretched at a strain level of 0.3-N, and this operation was counted as one cycle and was repeated 500 cycles.
Chemistry
January 2025
INDIAN INSTITUTE OF SCIENCE EDUCATION AND RESEARCH PUNE, CHEMISTRY, HOMI BHABA ROAD, PASHAN, PUNE, 411008, PUNE, INDIA.
In this work, we have reduced CO2 with HBpin to afford borylated methanol product selectively in ~99% yield using Ce[N(SiMe3)2]3(THF)3 as a catalyst. This led to multigram scale isolation of methanol obtained from CO2 reduction via the hydrolysis of borylated methanol, this establishes the potential of Ce[N(SiMe3)2]3(THF)3 as an efficient homogeneous catalyst for the bulk scale methanol synthesis. A practical application of this catalytic system was also shown by reducing CO2-containing motorbike exhaust efficiently and selectively.
View Article and Find Full Text PDFChemistryOpen
January 2025
Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
5-Enolpyruvylshikimate-3-phosphate synthase (EPSPS) catalyzes the conversion of 5-enolpyruvate (PEP) and shikimic acid phosphate (S3P) to 5-enolpyruvylshikimic acid-3-phosphate (EPSP), releasing inorganic phosphate. This reaction is the sixth step of the shikimate pathway, which is a metabolic pathway used by microorganisms and plants for the biosynthesis of aromatic amino acids and folates but not in mammals. In the present study, the detailed reaction mechanism of EPSPS from Nicotiana tabacum (NtEPSPS) is revealed by quantum chemical calculations with the cluster approach.
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