Poly , Alkali Metal Complexes

An exhaustive review on di- and poly-alkali-metal derivatives of heterofunc-tionally substituted organic molecules contains many useful references on aromatic ring metallation, particularly of nitrogen- and sulphur-containing heteroaromatics. Other reviews include a description of the use of chromium tricarbonyl-arene complexes in organic synthesis and the preparation and use in synthesis of highly reactive metal powders. ... 

Poly (macrocyclic) compounds. The analytical application of compounds such as crown polyethers and cryptands is based on their ability to function as ligands and form stable stoichiometric complexes with certain cations. Special importance is due to their preference for alkali metal ions which do not form complexes with many other ligands. A number of these compounds are commercially available and their properties and analytical applications have been described by Cheng et a/.11... 

Polymeric pseudocrown ether networks have been generated in situ by the photopolymerization of poly(ethylene glycol) diacrylate transition metal complexes <00CM633>, and the effect of metal ion templation was evaluated. The 1,6,13,18-tetraoxa[6.6]paracyclophane-3,15-diyne (termed pyxophanes) was prepared from hydroquinone and l,4-dichlorobut-2-yne it forms size-selective 7i-complexes with alkali metal cations <00CC2377>. Dibenzo[ ]crown-m have been used in numerous elegant studies in which they were the needles that were threaded by diverse reagents the resultant... 

The interaction of poly(ethylene oxide) and other polar polymers with metal salts has been known for many years (Bailey and Koleska, 1976). Fenton, Parker and Wright (1973) reported that alkali metal salts form crystalline complexes with poly(ethylene oxide) and a few years later, Wright (1975) reported that these materials exhibit significant ionic conductivity. Armand, Chabagno and Duclot (1978, 1979) recognised the potential of these materials in electro-chemical devices and this prompted them to perform more detailed electrical characterisation. These reports kindled research on the fundamentals of ion transport in polymers and detailed studies of the applications of polymer-salt complexes in a wide variety of devices. 

Polymer electrolytes (e.g., poly (ethylene oxide), poly(propylene oxide)) have attracted considerable attention for batteries in recent years. These polymers form complexes with a variety of alkali metal salts to produce ionic conductors that serve as solid electrolytes. Their use in batteries is still limited due to poor electrode/electrolyte interface and poor room temperature ionic conductivity. Because of the rigid structure, they can also serve as the separator. Polymer electrolytes are discussed briefly in section 6.2. 

Lithium polymer batteries are similar in principle to the lithium batteries described above but the electrolyte is a polymer. The advantage of these batteries is the absence of liquid in the cell and so the batteries do not leak. The polymer electrolyte is a polymer-alkali metal salt complex. The best known such electrolytes are complexes of poly (ethylene) oxide (PEO). 

The introduction at the C- or N-terminal position of a crown ether unit has been used as a strategy to control the aggregation of poly(benzyl glutamate) derivatives 19 The incorporation of the crown unit at the C-terminal position is performed using (benzo-15-crown-5)-4-amine as initiator of the polymerization of l-G1u(OBz1)-NCA. Physical properties of such crown derivatives can be modulated by the formation of sandwich 2 1 complexes driven by the addition of specific alkali metal ions. In the reported case, the formation of K+ sandwich complex between two C-terminal benzo-15-crown-5 modified helical polypeptides induced aggregation. In a similar approach,f20 addition of Cs+ to 18-crown-6 terminated helical peptides results in the formation of supramolecular assemblies having membrane ion conductivity activities. 

There is a range of polysulfide dianions 8 that can be obtained by reaction of sulfur with simple sulfides, by high-temperature reaction of an alkali metal with sulfur, or by reaction of alkali metals with sulfur in liquid ammonia. Often, once formed, the anions are in equilibrium in solution, but individual anions can be complexed successfully. 8tructures of the free poly sulfide anions are shown in Figure 31. 

Rod—coil copolymers are a type of amphiphile that can self-assemble into a variety of ordered nanostructures in a selective solvent.36-37-71 In solvents that selectively dissolve only coil blocks, rod—coil copolymers can form well-defined nanostructures with rod domain consisting of the insoluble block. This results in an increase of the relative volume fraction of the coil segments relative to the rod segments, which gives rise to various supramolecular structures. Particularly, poly(alkylene oxide) as the coil block of rod—coil molecule has additional advantages due to complexation capability with alkali metal cation, which can provide an application potential for solid polyelectrolytes and induce various supramolecular structures.72-75... 

In contrast to conventional cation exchangers, a reversed elution order is observed with crown ether phases, which is mainly determined by the size ratio between crown ether ring and alkali metal ion. Due to the high affinity of poly(benzo-15-crown-5) toward potassium and rubidium ions, these are more strongly retained than lithium, sodium, and cesium ions, respectively. However, the complexing properties of crown ethers also depend on the counter ion being employed. Thus, in potassium salts, for example, an increase in retention in the order KC1 < KBr < KI is observed with an increasing size of the counter ion. 

Beryllium in tap water, dialysis fluids and alkali-metal salts was determined with Chrome Azurol S after preconcentration of the complex on a column packed with polyethylene powder [1]. Sorption preconcentration of Be on a fibrous sorbent (poly(acrylonitrile)-carboxylated polyethylene-polyamine) prior to the determination of metal with Arsenazo I in sea water was described [2]. 

Compounds of Tl have many similarities to those of the alkali metals TIOH is very soluble and is a strong base TI2CO3 is also soluble and resembles the corresponding Na and K compounds Tl forms colourless, well-crystallized salts of many oxoacids, and these tend to be anhydrous like those of the similarly sized Rb and Cs Tl salts of weak acids have a basic reaction in aqueous solution as a result of hydrolysis Tl forms polysulfides (e.g. TI2S5) and poly iodides, etc. In other respects Tl resembles the more highly polarizing ion Ag" ", e.g. in the colour and insolubility of its chromate, sulfide, arsenate and halides (except F), though it does not form ammine complexes in aqueous solution and its azide is not explosive. 

The synthesis of MEEP involves the reaction of poly(dichlorophosphazene) with the sodium salt of methoxy ethoxy ethanol. The byproduct in this reaction is sodium chloride which has to be separated from the polymer completely, since even traces of the ionic impurities would lead to spurious results. However, unfortunately MEEP is also soluble in water and therefore separation from sodium chloride is rendered extremely difficult. A cumbersome and lengthy dialysis procedure is required to effect the separation and purification of the polymer. Further MEEP is also hydrophilic and residual water in the polymer is an undesirable feature for a solid electrolyte particularly when involved with alkali metal salt complexes. Additionally the dimensional stability of MEEP is poor and has been commented upon above. 

Metal-alkyne a complexes (2) and poly-yne analogues (28) are generally prepared by one of the following strategies (a) reaction of alkali metal... 

Our background with chelate complexes suggested the use of Group IA and IIA metal salts for selective polyamine complexation. The specificity of the interaction between alkali-metal and alkaline-earth salts and certain polyamines provides a sensitive technique for separating single polyamines from multicomponent samples. These separations, the factors that affect complex formation, and the unique properties of the poly-tertiary amine chelates of inorganic lithium compounds are discussed in this paper. 

Because the oxygen of ether compounds carries a net negative charge,68 a complex was reported to be formed between the oxygen of compounds such as poly(ethylene glycol) and metal ions, especially alkali metal and alkaline earth metal cations, due to the ion-dipole interactions of the positive charge of the... 

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