A set of new titanium-silsesquioxane epoxidation catalysts was discovered by exploring the hydrolytic condensation of a series of trichlorosilanes in highly polar solvents by means of high-speed experimentation techniques. The most promising silsesquioxane leads were prepared on a conventional laboratory scale and fully characterised. The lead generated by the hydrolytic condensation of tBuSiCl(3) in DMSO consisted of a set of incompletely condensed silsesquioxane structures, whereas that obtained from the hydrolytic condensation of tBuSiCl(3) in water consisted of a single silsesquioxane structure, tBu(2)Si(2)O(OH)(4). This is the first reported example of the use of this silsesquioxane as a precursor for active Ti catalysts. The Ti complexes prepared with tBu(2)Si(2)O(OH)(4) were supported on silica to produce active heterogeneous epoxidation catalysts.
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http://dx.doi.org/10.1002/chem.200305387 | DOI Listing |
ACS Omega
January 2025
Institute of Process Research and Development, School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
One use of CO as a starting material in organic transformations is in the synthesis of cyclic carbonates and polycarbonates. Due to the low reactivity of CO, this transformation must be carried out in the presence of an efficient catalyst. Although several catalytic systems have been developed in the past decade, reducing the CO pressure at which the reaction is carried out remains one of the main challenges of the process.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
BioCIS, Faculté de Pharmacie, Université Paris-Saclay, CNRS, Orsay 91400, France.
The endoperoxide scaffold is found in numerous natural products and synthetic substances of pharmaceutical interest. The main challenge to their synthetic access remains the preparation of chiral compounds due to the weakness of the peroxide bond, which limits the scope of available or applicable methods. Here, we demonstrate how peroxycarbenium species can be trapped by silylated nucleophiles with high enantioselectivities and diastereoselectivities when applicable, using a chiral imidophosphorimidate (IDPi) as a catalyst.
View Article and Find Full Text PDFThe carbon dioxide (CO) capture and utilization strategy has emerged as an innovative and multifaceted approach to counteract carbon emissions. In this study, a highly porous muffin polyhedral barium (Ba) ̵ organic framework (BaTATB; HTATB = 4,4',4″--triazine-2,4,6-triyl-tribenzoic acid) was synthesized solvothermally. The three-dimensional honeycomb pore architectures were densely populated with Lewis acidic Ba(II) metal sites and basic nitrogen-rich triazines.
View Article and Find Full Text PDFChem Asian J
January 2025
Indian Institute of Technology Ropar, Chemistry, Nangal Road, 140001, Rupnagar, INDIA.
Carbon dioxide (CO2) capture and its subsequent catalytic fixation into usable compounds represent a potential approach for addressing the energy problem and the implications of global warming. Hence, it is necessary to develop effective catalytic systems required for the transformation of CO2 into valuable chemicals/fuels. Herein, we rationally designed a hydroxyl-functionalized porous organic framework (OH-POF) consisting of both acidic (OH) as well as basic N sites for the transformation of CO2 using epoxides for the production of cyclic carbonates (CCs), a useful commodity chemical under environmental-friendly, metal/solvent/co-catalyst-free conditions.
View Article and Find Full Text PDFChemistry
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.
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