Synthesis and aggregation behavior of hosts containing phthalocyanine and crown ether subunits
| Autor: | M. M. Van Tilborg, R. Hendriks, O.E. Sielcken, Wiendelt Drenth, M.F.M. Roks, Roeland J. M. Nolte |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
chemistry.chemical_classification
Pyrazine Inorganic chemistry chemistry.chemical_element Free base General Chemistry Ring (chemistry) Biochemistry Copper Catalysis Solvent chemistry.chemical_compound Colloid and Surface Chemistry chemistry Polymerization Polymer chemistry Phthalocyanine Crown ether |
| Zdroj: | Journal of the American Chemical Society. 109:4261-4265 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja00248a021 |
| Popis: | Four new organic hosts are described that contain a phthalocyanine core to which four crown ether rings are attached. These hosts include a free base phthalocyanine with 18-crown-6 rings and three copper phthalocyanines with 15-crown-5, 18-crown-6, and 21-crown-7 rings. The macrocycles are synthesized from benzo crown ethers in three steps. In solution the phthalocyanines tend to form aggregates. This aggregation is affected by the polarity of the solvent and the presence of alkali-metal salts, which coordinate to the crowns. Cations with diameters that match the diameters of the crown ether rings form 4:4 host-guest complexes with the new hosts. Complexes with 8:4 host-guest stoichiometry are formed when the diameters of the cations exceed that of the crown ether rings. Binding free energies of the copper phthalocyanine hosts are presented and compared to those of benzo crown ethers. The binding profiles support the results of UV-vis experiments; i.e., that large cations induce aggregation of the macrocycles. Since the discovery of crown ethers by Pedersen, now 20 years ago,1 hundreds of papers have been published dealing with the chemistry of these compounds.2 An even larger number of papers have appeared on phthalocyanines and related macrocycles.3 Until recently, no papers have been published describing hosts in which both type of ring systems are incorporated.4 In the course of a program aimed at the development of new ion and electron carriers, we became interested in such mixed-ring systems as possible building blocks for the construction of ion channels. In previous papers we showed that ion channels can be synthesized by arranging crown ether rings in stacks.5 The stacks remain in a fixed position with the help of a rigid polymer support. Another possible route leading to stacks of crown ether rings could be one in which phthalocyanine rings containing crown ether subunits are polymerized (Figure 1). By chosing different ligands L (e.g., pyrazine, - O - , CN") and metals M a great variety of cascade complexes is possible. These complexes can be expected to transport ions and electrons in the direction of the stacks.5b'6 Here we report on phthalocyanines which have been functionalized with 15-crown-5, 18-crown-6, and 21-crown-7 rings: la-d.7 Their aggregation behavior in different solvents and in the presence of various alkali-metal salts is described. The construction of ion channels from la -d will be the subject of a separate paper. Results |
| Databáze: | OpenAIRE |
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