The major source of fluoride, namely calcium difluoride (CaF), is derived from the mineral fluorspar. Recent advances in the activation of CaF via mechanochemical methods have inspired investigation of the fundamental properties of Ca-F bonds in molecular complexes. However, the paucity of well-defined molecular Ca-F-containing complexes undermines systematic understanding of the factors governing nucleophilic fluoride delivery.
View Article and Find Full Text PDFBy exploiting the electronic capabilities of the N-heterocyclic boryloxy (NHBO) ligand, we have synthesized "naked" acyclic gallyl [Ga{OB(NDippCH)}] and indyl [In{OB(NDippCH)}] anions (as their [K(2.2.2-crypt)] salts) through K abstraction from [KGa{OB(NDippCH)}] and [KIn{OB(NDippCH)}] using 2.
View Article and Find Full Text PDFCalcium fluoride is the ultimate source of all fluorochemicals. Current synthetic approaches rely on the use of HF, generated from naturally occurring fluorspar and sulfuric acid. Methods for constructing E-F bonds directly from CaF have long been frustrated by its high lattice energy, low solubility and impaired fluoride ion nucleophilicity.
View Article and Find Full Text PDFAll fluorochemicals-including elemental fluorine and nucleophilic, electrophilic, and radical fluorinating reagents-are prepared from hydrogen fluoride (HF). This highly toxic and corrosive gas is produced by the reaction of acid-grade fluorspar (>97% CaF) with sulfuric acid under harsh conditions. The use of fluorspar to produce fluorochemicals via a process that bypasses HF is highly desirable but remains an unsolved problem because of the prohibitive insolubility of CaF.
View Article and Find Full Text PDFThe direct catalytic conversion of atmospheric CO to valuable chemicals is a promising solution to avert negative consequences of rising CO concentration. However, heterogeneous catalysts efficient at low partial pressures of CO still need to be developed. Here, we explore Co/CeO as a catalyst for the methanation of diluted CO streams.
View Article and Find Full Text PDFAiming at knowledge-driven design of novel metal-ceria catalysts for automotive exhaust abatement, current efforts mostly pertain to the synthesis and understanding of well-defined systems. In contrast, technical catalysts are often heterogeneous in their metal speciation. Here, we unveiled rich structural dynamics of a conventional impregnated Pd/CeO catalyst during CO oxidation.
View Article and Find Full Text PDFThe first example of photocatalytic trifluoromethoxylation of arenes and heteroarenes under continuous-flow conditions is described. Application of continuous-flow microreactor technology allowed to reduce the residence time up to 16 times in comparison to the batch procedure, while achieving similar or higher yields. In addition, the use of inorganic bases was demonstrated to increase the reaction yield under batch conditions.
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