2472-88-0Relevant articles and documents
Unbalanced-Ion-Pair-Catalyzed Nucleophilic Fluorination Using Potassium Fluoride
Hammond, Gerald B.,Li, Wangbing,Lu, Zhichao,Xu, Bo
supporting information, p. 9640 - 9644 (2021/12/14)
An unbalanced ion pair promoter (e.g., tetrabutylammonium sulfate), consisting of a bulky and charge-delocalized cation and a small and charge-localized anion, greatly accelerates nucleophilic fluorinations using easy handling KF. We also successfully converted an inexpensive and commercially available ion-exchange resin to the polymer-supported ion pair promoter (A26–SO42–), which could be reused after filtration. Moreover, A26–SO42– can be used in continuous flow conditions. In our conditions, water is well-tolerated.
Unique fluoride anion complexation in basic media by 5,5-dioxophenothiazine bis(phenylurea) and bis(phenylthiourea)
Kormos, Attila,Móczár, Ildikó,Pál, Dávid,Baranyai, Péter,Holczbauer, Tamás,Palló, Anna,Tóth, Klára,Huszthy, Péter
, p. 8142 - 8146 (2013/09/02)
The anion recognition properties of the newly synthesized 5,5-dioxophenothiazine bis(phenylurea) and bis(phenylthiourea) were investigated in acetonitrile using UV-vis spectroscopy. While most of the studied anions were bound only by the neutral receptors
Molecular Metals with Widely Tunable Band Filling. Structure/Stoichiometry/Counterion Relationships in the Electrochemistry of a Cofacially Joined Polymeric Phthalocyanine Metal
Gaudiello, John G.,Kellogg, Glen E.,Tetrick, Stephen M.,Marks, Tobin J.
, p. 5259 - 5271 (2007/10/02)
The oxidative electrochemistry of the cofacially joined phthalocyanine polymer n to yield molecular metals/conductive polymers of the type Xy>n is studied by combination of X-ray diffractometric and spectroscopic techniques.Electrochemical methodology includes controlled-potential coulometry and electrochemical potential spectroscopy (ECPS) applied to rapidly stirred slurries or to microcompactions of the solid polymer.For X(1-)= BF4(1-) in acetonitrile, oxidation ("dopping") of as-polymerized orthorhombic n to yield tetragonal(BF4)y>n (y ca. 0.50) is accompanied by a significant overpotential, minimal tunability in y, and involves a first-order structural phase-transformation.Electrochemical undoping occurs smoothly and over a broader potential range (0.90 V) to afford tetragonal n, which is also accesible by thermally undoping I1.1>n.Once in the more open tetragonal structure, both the electrochemical and diffraction data argue that y (hence, conduction band filling) can be homogeneously/continuously tuned between 0.0 and 0.50.This result verifies the crystal structural basis of the polymer electrochemical "break-in" phenomenon.It also represents the first case in which the band filling of a molecular metal is broadly tunable.In tetrahydrofuran, tetragonal n can also be reversibly n-doped to yield 0.09>n.Oxidative ECPS studies with a number of anions in acetonitrile (PF6(1-), SbF6(1-), tosylate, CF3(CF2)nSO3(1-), n=0,3,7) demonstrate that maximum doping stechiometries achievable (y, hence band filling) are largely a function of anion size, i.e., packing constraints within thetetragonal Xy>n crystal structure.In contrast to these results, ECPS studies of solid Ni(Pc) (monoclinic slipped-stack β phase) reveal a first-order structural transformation to yield tetragonal Ni(Pc)(BF4)y (y ca. 0.48) upon oxidative doping, and a subsequent first-order transformation to another slipped-stack Ni(Pc) structure (monoclinic slipped-stack γ phase) upon undoping.Doping/undoping occurs over a relatively narrow potential range; consequently there is far less tunability in y than in the Xy>n materials, and large overpotentials are observed.ECPS studies of n reveal irreversible oxidative processes, and polymer decomposition via Ge-O bond cleavage is implicated.
