0000000000597798
AUTHOR
Moniralsadat Tabatabai
showing 7 related works from this author
ChemInform Abstract: Dissymmetric Calix(4)arenes with C4- and C2-Symmetry. Synthesis, X-Ray Structures, Conformational Fixation, and 1H NMR Spectrosc…
2010
ChemInform Abstract: Calix(4)arenes with Resorcinol Units Incorporated in 2,6-Position.
2010
A resorcinol derived calix[5]arene with C5-symmetry
1994
Abstract Condensation of 2,4-dihydroxy-3-hydroxymethyl benzophenone (4) in dioxane/H2SO4 gave the cyclic pentamer 5, a calix[5]arene with regular incorporation of the resorcinol units via their 2- and 6-positions. The structure follows from the 1H NMR and mass spectra and was further confirmed by single crystal X-ray analysis. Dynamic NMR in C2D2Cl4 gave a surprisingly high barrier of ΔG‡ = 17.3 kcal/mol for the cone-to-cone ring inversion.
Metal ion complexation by tetraester derivatives of bridged calix [4] arenes
1992
A series of bridged calix [4] arenes (5–10 methylene groups in the bridge) were synthesized and transformed into their tetraester derivatives by reaction with ethyl bromoacetate. The stability constants for complexes of the tetraester derivatives with sodium, potassium and silver cations, determined in methanol by spectroscopic or potentiometric techniques, show a drastic decrease (more than 105 for Na +) for the shorter methylene chains. 1H NMR studies demonstrate a conformational rearrangement of the calixarene part to fourfold symmetry to be necessary for the complexation of a cation, which is prevented by the shorter chains. This is further confirmed by the X-ray structure of a tetraest…
Inherently Chiral Calixarenes
1994
Due to the nonplanarity of the basic 1 n -metacyclophane system, calixarenes and resorcarenes can be transformed into molecules with inherent chirality. Various attempts to achieve this goal are reviewed. Special emphasis is given to derivatives with C n -symmetry, including derivatives of spherand calixarenes and other calixarene-like macrocycles.
Dissymmetric calix[4]arenes: Optical resolution of some conformationally fixed derivatives
1993
Various possibilities to obtain intrinsically chiral calix[4]arenes are discussed. The enantiomers of three 1,3-dietheresters and one monoether compound derived from dissymmetric calix[4]arenes with C4 symmetry were separated by HPLC using chiral stationary phases and characterized by their CD spectra. © 1993 Wiley-Liss, Inc.