Unusually rigid macrocyclic tris(picolinolato)-4-tert-butylcalix[4]arene: Its intramolecular interaction effect on picolinoylation

作者：Lee Haeri; Noh Tae Hwan; Kim Eun Ji; Jung Ok Sang^*

来源：Journal of Molecular Structure, 2012, 1027: 53-56.

DOI：10.1016/j.molstruc.2012.06.015

• Macrocycles
• NMR spectroscopy
• Noncovalent interactions
• Picolinoylation
• Steric hindrance

The reaction of 4-tert-butylcalix[4]arene (calix[4]) with picolinoyl chloride affords only the unprecedented rigid tris(pico)-product calix[4]-(pico)(3)(OH) (pica picolinoylato) with an upper-rim and two lower-rim pica groups, via a subtle combination of steric hindrance and intrinsically weak intramolecular interactions. The chemical shift of one of the upper-rim pico group%26apos;s aromatic protons appears, unusually, 5.18 ppm in chloroform, which is the quite up-field chemical shift of the reported aromatic proton signals.

• 出版日期2012-11-14