NO[Al(OC(CF3)2Ph)4]
1 and NO[Al(OC(CF3)3)4]
2 were obtained by the metathesis reaction of NO[SbF6] and the corresponding Li[Al(OR)4] salts in liquid sulfur dioxide solution in ca 40%
(1) and 85%
(2) isolated yield. 1 and 2, as well as Li[NO3] and N2O, were also given by the reaction of an excess of mixture of (90 mol%) NO, (10 mol%) NO2 with Li[Al(OR)4] followed by extraction with SO2. The unfavourable disproportionation reaction of 2NO2(g) to [NO]+(g) and [NO3]−(g)
[ΔH°
=
+616.2 kJ mol−1] is more than compensated by the disproportionation energy of 3NO(g) to N2O(g) and NO2(g)
[ΔH°
=
−155.4 kJ mol−1] and the lattice energy of Li[NO3]
(s)
[UPOT
= 862 kJ mol−1]. Evidence is presented that the reaction proceeds via a complex of [Li]+ with NO, NO2
(or their dimers) and N2O. NO2 and Li[Al(OC(CF3)3)4] gave {NO3(NO)3}[Al(OC(CF3)3)4]2, NO[Al(OC(CF3)3)4] and (NO2)[Al(OC(CF3)3)4] products. The aluminium complex {Li[AlF(OC(CF3)2Ph)3]}23 was prepared by the thermal decomposition of Li[Al(OC(CF3)2Ph)4]. Compounds 1 and 3 were characterized by single crystal X-ray structural analyses, 1–3 by elemental analyses, NMR, IR, Raman and mass spectra. Solid 1 contains [Al(OC(CF3)2Ph)4]− and [NO]+ weakly linked via donor acceptor interactions, while in the SO2 solution there is an equilibrium between the associated [NO]+[Al(OC(CF3)2Ph)4]− and separated solvated ions. Solid 2 contains essentially ionic [NO]+ and [Al(OC(CF3)3)4]−. Complex 3 consists of two {Li[AlF(OC(CF3)2Ph)3]} units linked via fluorine lithium contacts. Compound 1 is unstable in the SO2 solution and decomposes to yield [AlF(OC(CF3)2Ph)3]−, [(PhC(CF3)2O)3Al(μ-F)Al(OC(CF3)2Ph)3]− anions as well as (NO)C6H4C(CF3)2OH, while compound 2 is stable in liquid SO2. The ν(NO+) in 1 and [NO]+(toluene)[SbCl6] are similar, implying similar basicities of [Al(OC(CF3)2Ph)4]− and toluene.
You have access to this article
Please wait while we load your content...
Something went wrong. Try again?