Salts exotic

Exotic Salts of Lithium, Rubidium and Caesium and their Formulations... 

Synthetic procedures for many ammine complexes are given by Schlessinger. Table 3 lists some (sometimes exotic) salts of representative ammine complexes, together with the average metal NH3 bond distance and an estimate of the average M NH3 bond energy. 

TNT and picric acid have been replaced gradually by tetryl, RDX, and nitroglycerine (Section 9-11). On the research front, chemists are continuing to explore novel structures. A case in point is octanitrocubane, synthesized in 2000, in which ring strain adds to the brisance of the compound. Its molecular formula, CgNgOig, indicates the potential to generate 8 CO2 -f 4 N2 molecules, with an associated 1150-fold volume expansion. A recent example from 2012 is the exotic salt TKX-50, in which two lone carbon atoms are surrounded by 10 nitrogens and the equivalent of 4 H2O moieties. 

It is impossible to recommend how far you should pursue the possibilities discussed in this chapter. Essentially, all analytical process developers routinely screen both anion and cation exchangers with salt gradients over a range of fixed pH values. A smaller subset routinely evaluates pH gradients as well. Exploration into more exotic territory is usually undertaken only when conventional approaches fail. This is probably as it should be. As powerful and versatile as IEC is, it is only one of a suite of proven chromatography techniques for protein analysis. If investigating the basics in IEC does not yield the results you seek, it... 

Although these two methods have found widespread application for the synthesis of free carbenes, they failed for selected saturated imidazolidin-2-ylidenes and especially in the preparation of triazolin-5-ylidenes. In these cases the free carbene species 7 can be obtained from 2-alkoxyimidazolidines 6 [44] or 5-aUcoxytriazoles [36] by thermally induced ot-elimination of an alcohol (Fig. 5). In addition to 2-aUcoxyimidazolidmes, 2-(pentafluorophenyl)imidazolidines [45, 46] have also been used for the generation of NHCs by cx-elimination. The adduct 8 eliminates acetonitrile upon heating [47] to yield the benzimidazolin-2-ylidene 9. In a more exotic procedure, imidazolium salts have been reduced electrochemically to give the free imidazolin-2-ylidenes [48]. 

Somewhat more exotic is the reaction of benzopyrylium salts with alkenes, which yields... 

Ammonium carbamate is prepared from dry ice and liquid ammonia [14]. These conditions are very similar to the conditions under which we have observed the formation of amine salts. To some readers, ammonium carbamate may seem to be an exotic compound. In fact, it is manufactured industrially on a multiton scale, because on heating (usually at 100-185°C) ammonium carbamate is converted to urea and water [14-16]. Urea is important for both the agricultural and the plastics industries. The ammonium carbamate is not always isolated during urea preparation. Instead, the reactions are carried out under conditions where the carbamate is just an intermediate. Ammonium carbamate is only moderately stable and it gradually loses ammonia in air. Although the data are sparse, the rate of decomposition of carbamates in solution seems to decrease as the volatility of the parent amine decreases [17]. Free carbamic acids in solution do not decompose spontaneously to free amine and C02. Instead, the acid ionizes by reaction with water the proton is transferred from the hydronium ion to the amine and then decomposition occurs [17]. Acids catalyze the decomposition. 

In recent years, more novel methods have been developed by chemists in order to hasten the reaction between solids or to grow single crystals of new and exotic solids. Among those included in the following syntheses are electrolysis of fused salts, chemical transport, and hydrothermal crystal growth. 

Metal salts with other cations are synthesized in a similar manner. Among these studies, the obtaining of coordination compounds of copper(II) in methanol with N2S2 ligand environment should be mentioned. These complexes are of permanent interest due to the modeling of active centers of blue copper proteins on their basis (see Sec. 2.2.5.4) [235-237]. Such complexes were obtained, in particular, by interaction of divalent copper perchlorate and tetrafluoroborate with very exotic ligands 661 and 662 in methanol [238] ... 

Catalyst Description. The LPO catalyst is a triphenylphosphine modified carbonyl complex of rhodium. Triphenylphosphine, carbon monoxide, and hydrogen form labile bonds with rhodium. Exotic catalyst synthesis and complicated catalyst handling steps are avoided since the desired rhodium complex forms under reaction conditions. Early work showed that a variety of rhodium compounds might be charged initially to produce the catalyst. Final selection was made on the basis of high yield of the catalyst precursor from a commodity rhodium salt, low toxicity, and good stability to air, heat, light, and shock. 

Adhesives may experience many different and exotic environments. Environmental aging of adhesives is accomplished by exposing a stressed or unstressed joint to simulated operating conditions. Exposure is typically to elevated temperature, water, salt spray, or various chemical solutions that simulate the service conditions. A number of standard chemicals that are used to soak bonded specimens for 7 days at room temperature are... 

Interesting potential applications of molten salts are electroplating and electrorefining of refractory metals and rare earth metals. Electrowinning of titanium has been tested on a pilot scale. Electrodeposition of refractory compounds like TiB2 has also been demonstrated. Due to space limitations these more exotic applications of molten salts will not be treated here. However, short chapters on molten salt batteries and fuel cells are included. 

Nickel(IV) is also known, but this oxidation state appears to be confined to the red salt, K2NiF6, the black nickelate, K2Ni03, and a number of rather exotic complexes. 

Since its discovery in 1985, Appel salt 770 has been exploited for nucleophilic displacement reactions. For example, it reacts readily with amines, e.g., Scheme 150 <2002J(P1)1535> (or hydrazine <1996TL3709>), a more exotic example being its reaction with methyl 3-aminocrotonate resulting in formation of an isothiazole 771 (Scheme 151) <1998J(P1)77>. 

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