Conformational analysis of calix[n] arenes with chiral substituents by using circular dichroism

Calix [n] arenes (n= 4 and 6) bearing chiral substituents (R*) on the lower rim (1n) or on the upper rim (4n) were synthesized. The isomers derived from 14 were conformationally immobile and showed different circular dichroism (CD) spectra. In the 1H NMR spectra the proton signals in R* shifted to higher magnetic field when the lower rim is sterically crowded and in the CD spectra a strong CD band appeared. Therefore, the change in the CD spectra is rationalized in terms of R*…π interactions. In contrast, compound 44 was not conformationally immobilized and the CD spectra changed in response to the metal binding to the methoxy oxygens arranged on the lower rim. The specific metal interaction enabled the metal binding event to be detected by the CD technique.

[1]  Katsuhira Yoshida,et al.  New chromoionophores based on indoaniline dyes containing calix[4]arene , 1991 .

[2]  J. Atwood,et al.  Water Soluble Calixarene Salts. A Class of Compounds with Solid-State Structures Resembling Those of Clays , 1991 .

[3]  S. Shinkai,et al.  Conformations and structures of tetra-O-alkyl-p-tert-butylcalix[4]arenes. How is the conformation of calix[4]arenes immobilized? , 1991 .

[4]  D. Reinhoudt,et al.  syn-1,2-dialkylated calix[4]arenes : general intermediates in the NaH/DMF tetraalkylation of calix[4]arenes , 1991 .

[5]  P. Nieto,et al.  Carbon-13 NMR chemical shifts. A single rule to determine the conformation of calix[4]arenes , 1991 .

[6]  D. Reinhoudt,et al.  The 1,2-alternate conformation of calix[4]arenes: a rare comformation? Dynamic $1$H NMR studies of flexible tetraalkylated calix[4]arenes , 1991 .

[7]  T. Arimura,et al.  New water-soluble host calixarenes bearing chiral substituents , 1991 .

[8]  S. Shinkai,et al.  Syntheses of all possible conformational isomers of O-alkyl-p-t-butylcalix[4]arenes , 1991 .

[9]  D. Reinhoudt,et al.  SELECTIVE FUNCTIONALIZATION OF CALIX(4)ARENES AT THE UPPER RIM , 1990 .

[10]  S. Shinkai,et al.  Remarkable metal template effects on selective syntheses of p-t-butylcalix[4]arene conformers , 1990 .

[11]  D. Reinhoudt,et al.  Kinetically stable complexes of alkali cations with rigidified calix[4]arenes: synthesis, X-ray structures, and complexation of calixcrowns and calixspherands , 1989 .

[12]  C. Gutsche,et al.  Calixarenes 9 : Conformational isomers of the ethers and esters of calix[4]arenes , 1983 .