A Rearrangement Reaction to Yield a NH(4)(+) Ion Driven by Polyoxometalate Formation

[Image: see text] Triethylamine is a volatile liquid and exists in the atmosphere in the gas phase. It is a hazardous air pollutant and identified as a toxic air contaminant. Thus, producing ammonia (a vital chemical for fertilizer production) from the vapor state of this toxic substance is a challenging task. Diffusion of the vapor of triethylamine, (C(2)H(5))(3)N, into an acidified aqueous solution of sodium molybdate results in the formation of single crystals of compound [(C(2)H(5))(3)NH](2)[(C(2)H(5))(4)N][NaMo(8)O(26)] (1). Notably, compound 1 includes a [(C(2)H(5))(4)N](+) cation, even though the concerned reaction mixture was not treated with any tetraethylammonium salt. The formation of the [(C(2)H(5))(4)N](+) cation from (C(2)H(5))(3)N in an acidic aqueous medium is logically possible only when an ammonium cation (NH(4)(+)) is formed in the overall reaction: 4(C(2)H(5))(3)N + 4H(+) = 3[(C(2)H(5))(4)N](+) + [NH(4)](+). Although the resulting NH(4)(+) cation (identified by Nessler’s reagent test) is not included in the crystals of compound 1 as a cation, it can be made associated with a crown ether in the isolation of single crystals of compound [NH(4)⊂B15C5](3)[PMo(12)O(40)]·B15C5 (2), (B15C5 = benzo-15-crown-5). Crystal structure analysis and (1)H NMR studies of compound 2 have established the presence of an H-bonded NH(4)(+) ion in compound 2, thereby established the rearrangement reaction.