Sodium cation ethers

Initially, on addition of sodium cations to a solution of the ligand, two distinct CV waves were observed, corresponding to the uncomplexed and complexed compound [1] (Fig. 4) (Chariot et al., 1962). Hie wave at the higher positive potential corresponds to the solution complexed species. Hie oxidized ferrocene crown ether has a lower binding constant with sodium than the... 

Sodium Cation Binding by Nitrogen-pivot. Lariat Ethers... 

Solvents, specifically surrounding the sodium cation, lower its effect. In the presence of a crown ether, including and blockading the sodium cation, the rate of the final product formation is entirely restored. 

The conjugation in the molecular wire may be disrupted or modulated to create systems with different properties. For example, a porphyrin Ceo donor-acceptor system linked with a conjugated binaphthyl unit, has a preference for the atropi-somer where the fullerene unit is closer to the porphyrin system, thus increasing the through space interactions [82]. The charge transfer process on a dyad containing a crown ether in the linker structure can be modulated by complexation/ decomplexation of sodium cations [83] but even more interesting is the construction of supramolecular systems where the donor and acceptor moieties are... 

In a recent paper, Soumillion and co-workers [49] were able to identify CIP and SSIPin the P-naphtholate anion/alkali cation/tetrahydrofuran system. They found out that with lithium, a CIP is formed whereas with sodium/crown ether, a SSIP results. Using uncomplexed sodium or potassium counterion, mixtures of CIPs and SSIP s were detected. All their conclusions are based on spectral shifts in the transient absorption and emission spectra which were gained using laser flash spectroscopy. 

A biexponential decay was observed in weakly polar solvents like dioxane, THF or dimethoxyethane CIP and SSIP ion pairs coexist in these solvents with a majority of CIP in the case of lithium naphtholate while the SSIP dominates in the case of the potassium salt. In the presence of a crown ether and sodium cation, a monoexponential decay was observed and this allowed the attribution of the longest decay time to the SSIP. 

The tren-based heteroditopic receptor 22, featuring a tripodal tetrahedral amide hydrogen-bond anion-recognition site in combination with benzo-15-crown-5 ether cation-binding moieties, has been found to cooperatively bind chloride, iodide, and perrhenate anions via co-bound crown ether-complexed sodium cations. It also can efficiently extract the radioactive sodium pertechnetate from simulated aqueous nuclear waste streams. The anion-binding affinity of 22 is considerably reduced in the absence of a co-bound cation <1999CC1253>... 

If electrons are added into the crystal structure, they lead to the breaking of the Sn-Sn bonds, each atom carrying an unshared electron pair, and ultimately to the formation of isolated anionic clusters with triangular faces (deltahedra), known as Zintl ions (e.g. 1 and 2 see Chapter 1.6). These compounds are diamagnetic and poor conductors. They can be prepared either by reduction of tin with an alkali metal or electrochemically, and are soluble in polar, basic solvents. For example, [Na+]4 [Sng]" " can be prepared from the reaction of tin with sodium in ethylenediamine, or in the presence of a crown ether to associate with the sodium cations. The most common structure is a nine-atom cluster 2. ... 

Cs7[K-(2,2,2-crypt)](Sn9)2 3en.2 Apparently, the flat crown ethers have a similar size and shape effect. In addition, complete absence of a sequestering agent, as in Na4Sn9 7en and Li4Sn9 (NH3)i7, logically leads to the same clusters in the solid state. Finally, the crystallization of Sng with [Na-(2,2,2-crypt)l maybe due to the smaller size of the sodium cation and its effect on the overall size of the cryptated cation. 

The addition of sodium to aromatic hydrocarbons produces only the corresponding radical anion [121]. Alkali metals, however, dissolve in aliphatic ethers, e.g. tetrahydrofuran, dioxan, producing the characteristic blue colour [122], The solutions are diamagnetic because of the formation of higher ion pairs. Flash photolysis of solutions of sodium in ethers forms the ion pair consisting of the solvated electron and a sodium cation [123]. Three transients are formed in the flash photolysis of sodium pyrenide in tetrahydrofuran [124]. These have been identified as the solvated electron, es"oiv. the ion pair, esoiv> Na, and the sodium atom, Na°. Rate coefficients of reactions of es ,iv with various compounds relative to the rate of reaction with NjO have been determined recently by the 7-radiolysis of 2-methyl-tetrahydrofuran [125]. 

Steol CA-460 Surfactant Fatty ether sulfate. Sodium cation. (60% active) Stepan... 

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