Pseudo-cyclic face-to-face rigid structure caused by the intramolecular ion pair effect.
Six 3-methylpyridine zwitterions and six quinoline zwitterions were synthesized through the reaction of 4-hydroxycoumarins, p-benzoquinone and the corresponding N-aromatics. The novel pseudo-cyclic face-to-face rigid structure of the zwitterion was elucidated by (1)H-NMR at different temperatures, and assumed to be caused by both the intramolecular ion pair attraction and the steric interaction.
Zhang
Sheng-Ling
SL
Department of Chemistry, Shaoguan University, Shaoguan 512005, PR China. zhisland@yahoo.com.cn
Huang
Zhi-Shu
ZS
Gu
Lian-Quan
LQ
D015110:4-Hydroxycoumarins / Q000138:chemical synthesis / Q000737:chemistry; D007477:Ions; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D011725:Pyridines / Q000737:chemistry; D011804:Quinolines / Q000737:chemistry
D015110:4-Hydroxycoumarins; D007477:Ions; D011725:Pyridines; D011804:Quinolines