Thermodynamically controlled synthesis of nanocontainer molecules and study of hemicarceplex properties.

摘要

In chapter 1, a general overview about molecular container compounds is given.; Chapter 2 describes thermodynamically controlled nanometer-size container molecules syntheses using rigid building blocks. Reaction of 4 tetraformylcavitand 9 with 8 4,4'-ethylenedianiline yields quantitatively the distorted tetrahedral nanocontainer 26. The synthesis of octahedral nanocontainer 25 (60-80% yield) from 6 cavitands 9 and 8 1,3,5-tris(4'-aminophenyl)benzene "panels" involves a covalent paneling approach. Various intermediates on the pathway towards 25 have been identified by gel permeation chromatography and MALDI-TOF mass spectrometry. Based on these intermediates, a mechanism for formation of 25 is proposed and discussed.; Thermodynamically controlled container molecule syntheses are further explored in chapter 3. Chiral octaimino hemicarcerand 31 SSSS forms by reacting 4 equivalents (S)-2,2'-bis(aminomethyl)-1,1'-binaphthyl with 2 equivalents 9. When racemic 2,2'-bis(aminomethyl)-1,1'-binaphthyl is used, a dynamic covalent library, composed of 6 stereoisomeric hemicarcerands forms. The distribution of stereoisomers is strongly solvent dependent.; In chapter 4, isotope effects on the dissociation of naphthalene and p-xylene hemicarceplexes are examined. The rate constants were k( 36 ⊙ p-CH3-C6H4-CH 3) = k(36 ⊙ p-CH3-C6D4-CH 3) > k(36 ⊙ p-CD3-C6H4-CD 3) = k(36 ⊙ p-CD3-C6D4-CD 3) at 120°C and k(36 ⊙ C10H8) = k(36 ⊙ C10D8) between 147°C to 178°C. The observed kinetic isotope effects are discussed in terms of steric effects in the transition state and ground state effects. They strongly support the importance of gating in hemicarceplex dissociation. Finally, chromatographic behavior of various hemicarceplexes is discussed in chapter 5. The normal phase chromatographic retention times of a library of hemicarceplexes that differ in their size, shape and polarity were determined. The interaction free energy difference between stationary phase and mobile phase correlates linearly with the length of the polar axis of the hemicarceplexes for hemicarceplexes with similar shape. The molecular basis for the correlations is discussed. Furthermore, a set of isotopomeric p-xylene hemicarceplexes, which differ only in the degree of deuteration of the guest, were separated based on the guest's volume isotope effect.