Anion solvation, polymer-salt

While small ions such as Li+ which can be strongly solvated, lead to formation of polymer salt complexes even up to LiCl (lattice energy 853 KJ mob1) other larger cations such as Na+, K+ etc., require bulky counter anions such as I, SCN, or CF3SO3 in order to be solvated by PEO [38]. 

Ionic polymers may exist as undissociated, unsolvated ion pairs undissociated ion pairs solvated to some extent solvated ions dissociated to some extent or some combination of these. The propagation rate constant kp and the dissociation equilibrium constant K of the lithium salt of anionic... 

Solvent for Displacement Reactions. As the most polar of the common aprotic solvents, DMSO is a favored solvent for displacement reactions because of its high dielectric constant and because anions are less solvated in it (87). Rates for these reactions are sometimes a thousand times faster in DMSO than in alcohols. Suitable nucleophiles include acetyUde ion, alkoxide ion, hydroxide ion, azide ion, carbanions, carboxylate ions, cyanide ion, hahde ions, mercaptide ions, phenoxide ions, nitrite ions, and thiocyanate ions (31). Rates of displacement by amides or amines are also greater in DMSO than in alcohol or aqueous solutions. Dimethyl sulfoxide is used as the reaction solvent in the manufacture of high performance, polyaryl ether polymers by reaction of bis(4,4 -chlorophenyl) sulfone with the disodium salts of dihydroxyphenols, eg, bisphenol A or 4,4 -sulfonylbisphenol (88). These and related reactions are made more economical by efficient recycling of DMSO (89). Nucleophilic displacement of activated aromatic nitro groups with aryloxy anion in DMSO is a versatile and useful reaction for the synthesis of aromatic ethers and polyethers (90). 

Figure 5. (a) The ( A, SO,) anion symmetric streching mode of polypropylene glycol)- LiCF,SO, for 0 M ratios of 2000 1 and 6 1. Solid symbols represent experimental data after subtraction of the spectrum corre-ponding to the pure polymer. Solid curves represent a three-component fit. Broken curves represent the individual fitted components, (b) Relative Raman intensities of the fitted profiles for the ( Aj, SO,) anion mode for this system, plotted against square root of the salt concentration, solvated ions ion pairs , triple ions, (c) The molar conductivity of the same system at 293 K. Adapted from A. Ferry, P. Jacobsson, L. M. Torell, Electrnchim. Acta 1995, 40, 2369 and F. M. Gray, Solid State Ionics 1990, 40/41, 637. 

Several arylplatinum complexes of Tl+ have been reported (Table 15). The anionic /rreacts with T1N03 to produce a chain polymer 120, in which successive Pt atoms are bridged to each other by two Tl+ ions (Scheme 28).112 The compound is an acetone solvate, and there also appear to be weak Tl F interactions in the solid-state structure. Upon irradiation (A = 441 nm), the complex exhibits an intense emission with a maximum at 678 nm. The luminescence is attributed to MLCT transitions. 

One of the most interesting processes in electrically initiated polymerization was an initiation with the solvated electron proposed by Laurin and Parravano (22), who studied electro-anionic polymerization of 4-vinylpyridine in liquid ammonia solution of alkali metal salts in the temperature range — 33 to — 78° C. Rapid and efficient polymerization occurred and conversions of monomer to polymers formed exclusively at the cathode in the form of an orange-red, porous, solid deposit, suggesting the formation of a pile of living polymers. 

No exchange may take place when the metal is coordinatively unsaturated. Excluding metal powders, treated in 5.8.2.12.1, there are many salts that easily add CO. The coordinative unsaturation may be hidden, the metal salt being solvated by solvent molecules or existing as a dimer, polymer or cluster. The metal salt or complex can also contain bidentate or polydentate ligands or anions that leave a coordination site free for CO addition. 

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