Efficient uptake of small to large guests, with a large difference in relative size, is quite rare for synthetic host compounds. Herein we designed and prepared a micellar capsule, composed of bent amphiphiles bearing two adamantyl groups, as a new host with a well-defined nanostructure. Unlike previous covalent, coordination, and hydrogen-bonding hosts, the adamantanebased capsule displays unusual uptake abilities toward spherical molecules with small (∼0.6 nm in diameter; e.g., adamantane) to medium size (∼1 nm; e.g., fullerene) as well as large size (∼3 nm; i.e., metal−organic polyhedra (MOP)), where the size differences are up to 5-fold, in water. Moreover, the resultant MOP-uptaking capsule incorporates medium-sized molecules (e.g., perylene and eosin Y) into the polyhedral cavity to generate ternary core−shell structures.
Linear alkanes are essential building blocks for natural and artificial assemblies in water. As compared with typical, linear alkane-based micelles and recent aromatic micelles, we herein develop a cycloalkane-based micelle, consisting of bent amphiphiles with two cyclohexyl frameworks. This uncommon type of micelle, with a spherical core diameter of ~ 2 nm, forms in water in a spontaneous and quantitative manner. The cycloalkane-based, hydrophobic cavity displays peculiar host abilities as follows: (i) highly efficient uptake of sterically demanding Zn(II)-tetraphenylporphyrin and rubrene dyes, (ii) selective uptake of substituted Cu(II)-phthalocyanines and spherical nanocarbons, and (iii) uptake-induced solution-state emission of [Au(I)-dimethylpyrazolate]3 in water. These host functions toward the large metal-complex and other guests studied herein remain unaccomplished by previously reported micelles and supramolecular containers.
An aromatic oligomer micelle, featuring both high stability and high uptake ability, was quantitatively formed in water from amphiphilic oligomers, composed of three bent polyaromatic amphiphiles connected alternately by two hydrophilic chains. The well-defined micelle, with a diameter of ca. 2 nm, remains intact even under highly diluted conditions (ca. 3 mM) and at elevated temperature (> 130 8C), due to the polyaromatic chelate effect. The thermodynamic studies reveal that large enthalpic gain (DH = À110 kJ mol À1 ) is the key for the micelle formation. The oligomer micelle selectively encapsulates unsubstituted oligothiophenes (! 4-mer) to a high degree and the resultant, aqueous host-guest complexes display unusual emission derived from the multiply stacked oligomers. Furthermore, facile uptake and release of unsubstituted polythiophenes can be achieved using the oligomer micelle.
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