Advanced Salts—Other Anions

MOCF3 salts (M=K, Rb, and Cs) (Fig. 1.35c) have been prepared, however, by passing 0=CF2 through an acetonitrile solution of the fluoride MF [620,621]  

The difluoromethanimine acid (i.e., HN=CF2) (Fig. 1.35e) has been reported [604,605]. This is a colorless gas which is stable at ambient temperature for hours in the gas phase at pressures lower than 5 mm Hg, but which disproportionates at higher pressure  

The hthium hexafluoroisopropylidenimine salt (i.e., LiN=C(CF3)2) (Figs. 1.35e and 1.36c) has been reported [606-611]. The strong electron-withdrawing -CF3 

The lithium salt with the 4,5-dicyano-l,2,3-triazolate anion (DCTA-) (also known as 1,2,3-triazole-4,5-dicarbonitrile (TADC-)) (Fig. 1.38p) was first studied by Michot in 1995 [701] and reported in two publications in 2003 [664,665]. Little has been reported regarding the properties of the lithium salt. Alkali and alkali earth salts with the DCTA anion have also been prepared [666,667]. The thermal stability of these salts was found to be excellent ( 350 °C) [668]. hi general, triazole salts are known to be energetic. The alkali metal salts, however, were found to have low sensitivity towards impact, friction, electrostatic discharge, and fast heating [668]. The acid with the related pyrazole-3,4,5-tricarbonitrile anion (PATC-) (Fig. 1.38q) was first reported in 1962 [669], but the lithium salt has not been investigated extensively as an electrolyte salt [661, 670,671]. Similarly, the acid with the tetracyano-pyrrolide anion (TCP ) (Fig. 1.38r) was also reported in 1962 [672] and the sodium salt with this anion has been prepared [674]. Trifluoromethane-substituted versions of the C5(CN)5 and TCP anions have also been reported (Fig. 1.38v, w) [688-692], but the lithium salt has only been reported for LiC5(CF3)5 (Fig. 1.39k) [692]. 

Lithium salts with the 4,5-dicyano-2-(trifluoromethyl)imidazole (TDI ) (Fig. 1.39h) and 4,5-dicyano-2-(pentafluoroethyl)imidazole PDP) (Fig. 1.39i) 

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Once samples have been obtained, one can use a variety of available chemical, optical, spectroscopic, chromatographic, or other assays to determine concentration. For example, data in Figure 15-7 were obtained using a calibrated densito-metric technique in which one of the two species was colored in advance. Similar results have been obtained using other assay techniques, such as reflection near infrared spectroscopy to evaluate concentrations of magnesium stearate (a common pharmaceutical lubricant) or conductivity assays to evaluate the mixing of salt (NaCl, KCl) in anionic excipients (Avicel). 

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