Structure and FTIR spectra of 3:2 complexes of trimethylamine N-oxide and 4-dimethylamine-2,6-dimethylpyridine N-oxide with perchloric acid

S Krzywda, M Jaskolski, M Gdaniec, Z DegaSzafran, M GrundwaldWyspianska, M Szafran, Z Dauter, G Davies

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Trimethylamine N-oxide and 4-dimethylamine-2,6-dimethylpyridine N-oxide form three types of crystalline complexes with perchloric acid, with the base-to-acid ratio 1:1, 2:1 and 3:2, which are easily distinguished by their IR absorption. The asymmetric unit of the P (1) over bar unit cell contains two (Me(3)NO)(3) .(HClO4)(2) formula units. Each of the formula units assembles into a (Me(3)NO)(3)2H(+) dication and two independent ClO4- anions which show no H-bond interactions with the cationic components. The oxygen atom of a central trimethylamine N-oxide molecule accepts hydrogen bonds from two protonated trimethylamine N-oxide cations with O ... O distances in the range 2.537(5) - 2.562(7) Angstrom. The O ... H-O bonds are linear and formed along direction of the two electron lone-pairs on the oxygen atom. In acetonitrile solutions the 3:2 complexes exist as mixtures of the 1 : 1 and 2: 1 complexes.

Original languageEnglish
Pages (from-to)197-206
Number of pages10
Issue number3
Publication statusPublished - 10 Feb 1996



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