Crystal structure of the [protonated 2-(phenylazo)pyridine and protonated 2-(4-hydroxyphenylazo)pyridine (3 : 1)]tetrafluoroborate
โครงผลึกของ [protonated 2-(phenylazo)pyridine และ protonated 2-(4-hydroxy-phenylazo)pyridine (3 : 1)]tetrafluoroborate

Kaliyamoorthy Panneerselvam, Post Doctoral, D. of Physics, National Tsing Hua U., Hsinchu, Taiwan
Kanidtha Hansongnern, D. of Chemistry, F. of Sci., PSU.
Nattaporn Rattanawit, D. of Chemistry, F. of Sci., PSU.
Fen-Ling Liao, D. of Chemistry, National Tsing Hua U., Hsinchu, Taiwan
Tian-Huey Lu, D. of Physics, National Tsing Hua U., Hsinchu, Taiwan
Corresponding e-mail : hkanidth@ratree.psu.ac.th

Grant : Department of Chemistry, PSU. and Postgraduate Education and Research Program in Chemistry
Published : Analytical Sciences 2000, 16, 1107-1108
Key words : azo-compounds, 2-(phenylazo)pyridine

In general, geometrical isomerism of azo-compounds is known to exist in two forms, cis and trans. However, 2-(phenylazo)pyridine (or azpy) was synthesized to be in trans form only by Campbell and coworkers. The azpy molecule contains one nitrogen on pyridine and one on the azo moiety. They are acting as the donor atoms to metal ions. In acidic solution, both nitrogens can react with protons. However, this gives rise to a question, which nitrogen is more basic towards protons. In this work, we confirm that the azo nitrogen is more basic than the other by X-ray analysis.

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