X-ray and NMR investigation of 25,27-dihydroxy-26,28-bis(diethoxyphosphoryloxy)-tert-butylcalix[4]arene in the 1,2-alternate conformation
✍ Scribed by Janusz Lipkowski; Myroslav Vysotsky; Joanna Slowikowska; Vitaly I. Kalchenko; Leonid N. Markovsky
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 197 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0894-3230
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✦ Synopsis
The crystal structure of 25,27-dihydroxy-26,28-bis(diethoxyphosphoryloxy)-tert-butylcalix[4]arene (1) (hexane solvate, 1:1) was determined by x-ray crystallography. The crystal data are P2 1 /n, a = 12.652(1) A ˚, b = 12.564(2) A ˚, c = 18.781(4) A ˚, b = 105.56(1)°, V = 2876.0(8) A ˚3, Z = 2. In this complex the molecule adopts a 1,2alternate conformation. Both the calixarene and hexane molecules are centrosymmetric. The phenol units in the asymmetric part of the calix are inclined with respect to the main macrocyclic plane by 115.46(6)°and 128.01(7)°for the phosphorylated and the non-phosphorylated ring, respectively. Self-inclusion of the ethyl chains in the halfcavities is observed. One intramolecular O-H…O and several intermolecular C-H…O hydrogen bonds are present. In the 1 H NMR spectrum one average AX spin system for methylene bridge protons can be interpreted as fast (on the NMR time-scale) interconversion of non-phosphorylated phenol fragments.