Search results for "Ceramic"
showing 10 items of 2129 documents
A solvent-directed stereoselective and electrocatalytic synthesis of diisoeugenol.
2018
A stereoselective and electrocatalytic coupling reaction of isoeugenol has been reported for the first time in a 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)/boron-doped diamond (BDD) electrode system. This particular C-C bond formation and diastereoselectivity is driven by a solvate interaction between the radical species and another isoeugenol molecule. Due to an electrocatalytic cycle, only understoichiometric amounts of charge are necessary. Since electric current is directly employed as the oxidant, the reaction is metal and reagent-free. In addition, the electrolysis can be conducted in a very simple undivided beaker-type cell under constant current conditions. Therefore, the protocol is …
Enantioselective synthesis of 4H-pyranonaphthoquinones via sequential squaramide and silver catalysis
2015
Chemical communications 52(8), 1669-1672(2016). doi:10.1039/C5CC09592A
A concise route to MK-4482 (EIDD-2801) from cytidine.
2020
A two-step route to MK-4482 (EIDD-2801, 1) was developed consisting of an esterification and hydroxamination of cytidine. The selective acylation and direct amination eliminate the need for protecting and activating groups and proceed in overall yield of 75%, a significant advancement over the reported yield of 17%. The step count is reduced from five transformations to two, and expensive uridine is replaced with the more available cytidine.
Nucleophilic iodonium interactions (NIIs) in 2-coordinate iodine(i) and silver(i) complexes
2021
The generality of nucleophilic iodonium interactions (NIIs) has been demonstrated by preparing a range of silver(i) and iodonium (I+) complexes and studying their 15N NMR chemical shifts, with the first example of a NII-complex involving a 2-coordinate silver(i) complex being confirmed by X-ray crystallography, and its nucleophilicity studied by DFT calculations.
Spiro-fused bis-hexa-peri-hexabenzocoronene.
2018
A spiro-fused hexa-peri-hexabenzocoronene dimer was synthesized, and its physicochemical properties were studied by UV-Vis absorption and emission spectroscopy as well as cyclic voltammetry. Chemical oxidation of SB-HBC afforded its radical cation and dication derivatives, which could be reversibly reduced to the neutral state.
A decacobalt(ii) cluster with triple-sandwich structure obtained by partial reductive hydrolysis of a pentacobalt(ii/iii) Weakley-type polyoxometalat…
2016
Partial reductive hydrolysis of a penta-CoII/III cluster [CoII4(H2O)2(CoIIIW9O34)(PW9O34)]12− (1) leads to the formation of [Co2{Co3(H2O)(Co(OH)2W7O26)(PW9O34)}2]22− (2). This polyoxometalate is made up of two capping [PW9O34]9− units and two bridging [W7O26]10− units that assemble to encapsulate a novel deca-CoII cluster core comprising octahedral and tetrahedral CoII ions.
Electrochemical instability of highly fluorinated tetraphenyl borates and syntheses of their respective biphenyls
2018
Highly fluorinated tetraphenyl borate anions are of importance as weakly coordinating anions in metalorganic reactions. However, at high positive potentials their electrochemical stability in organic solvents is not sufficient. This was investigated by a comprehensive cyclic voltammetry study and can be used synthetically to generate highly fluorinated biphenyls.
The nature of interactions of benzene with CF3I and CF3CH2I
2019
In situ grown crystals of CF3I and CF3CH2I are dominated by I⋯I and F⋯F interactions. Their co-crystals with benzene, (CF3I)2·C6H6 and CF3CH2I·C6H6, contain two completely different sets of intermolecular interactions. (CF3I)2·C6H6 shows a unique halogen-bond type: above-the-bond C–I⋯πC6H6 interactions. CF3CH2I·C6H6 shows above-the-centre C–H⋯πC6H6 interactions. These interactions are electrostatically dominated type II halogen bonds between single halogenoalkane molecules and weaker dispersion dominated interactions between the co-crystal components. The observed preferences for benzene for the two binding partners match with calculated molecular electrostatic potentials.
Chiral footprint of the ligand layer in the all-alkynyl-protected gold nanocluster Au144(CCPhF)60
2019
The electronic structure and chiroptical properties of the recently isolated and structurally characterized all-alkynyl-protected gold nanocluster Au144(CCPhF)60 were analyzed via density functional theory (DFT) computations and compared to those of the structurally similar all-thiolate-protected Au144(SCH2Ph)60. While DFT predicts very strong CD signals of similar strength for both clusters, the origins of chiroptical activity are markedly different. The chiral response of Au144(CCPhF)60 originates only from the footprint of the outermost gold-ligand layer of 30 FPhCC-Au-CCPhF units covering an achiral Ih-symmetric Au114 core whereas the Au114 core of the Au144(SCH2Ph)60 cluster has a chir…
Advances in photochemical and electrochemical incorporation of sulfur dioxide for the synthesis of value-added compounds.
2021
Organic photochemistry and electrochemistry currently receive tremendous attention in organic synthesis as both techniques enable the reagent-less activation of organic molecules without using expensive and hazardous redox reagents. The incorporation of SO2 into organic molecules is a relatively modern research topic, which likewise gains immense popularity since the discovery of the SO2 surrogate DABSO. Sulfur-containing organic molecules are omnipresent in pharmaceuticals and agrochemicals. This review covers the recent progress in electrochemical and photochemical methodologies for the incorporation and uses of SO2 in the synthesis of value-added compounds. Additionally, different work t…