Abstract
Nature routinely uses cooperative interactions to regulate cellular activity. For years, chemists have designed synthetic systems that aim toward harnessing the reactivity common to natural biological systems. By learning how to control these interactions in situ, one begins to allow for the preparation of man-made biomimetic systems that can efficiently mimic the interactions found in Nature. To this end, we have designed a synthetic protocol for the preparation of flexible metal-directed supramolecular cofacial porphyrin complexes which are readily obtained in greater than 90% yield through the use of new hemilabile porphyrin ligands with bifunctional ether-phosphine orthioether-phosphine substituents at the 5 and 15 positions on the porphyrin ring. The resulting architectures contain two hemilabile ligand-metal domains (RhI or CuI sites) and two cofacially aligned porphyrins (ZnII sites), offering orthogonal functionalities and allowing these multimetallic complexes to exist in two states, "condensed" or "open". Combining the ether-phosphine ligand with the appropriate RhI or CuI transition-metal precursors results in "open" macrocyclic products. In contrast, reacting the thioether-phosphine ligand with RhI or CuI precursors yields condensed structures that can be converted into their "open" macrocyclic forms via introduction of additional ancillary ligands. The change in cavity size that occurs allows these structures to function as allosteric catalysts for the acyl transfer reaction between X-pyridylcarbinol (where X = 2, 3, or 4) and 1-acetylimidazole. For 3- and 4-pyridylcarbinol, the "open" macrocycle accelerates the acyl transfer reaction more than the condensed analogue and significantly more than the porphyrin monomer. In contrast, an allosteric effect was not observed for 2-pyridylcarbinol, which is expected to be a weaker binder and is unfavorably constrained inside the macrocyclic cavity.
Original language | English (US) |
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Pages (from-to) | 16286-16296 |
Number of pages | 11 |
Journal | Journal of the American Chemical Society |
Volume | 128 |
Issue number | 50 |
DOIs | |
State | Published - Dec 20 2006 |
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
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CCDC 637777: Experimental Crystal Structure Determination
Oliveri, C. G. (Creator), Gianneschi, N. (Creator), Nguyen, S. (Creator), Mirkin, C. A. (Creator), Stern, C. L. (Creator), Wawrzak, Z. (Creator) & Pink, M. (Creator), Cambridge Crystallographic Data Centre, 2007
DOI: 10.5517/ccpdng5, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccpdng5&sid=DataCite
Dataset
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CCDC 637779: Experimental Crystal Structure Determination
Oliveri, C. G. (Creator), Gianneschi, N. (Creator), Nguyen, S. (Creator), Mirkin, C. A. (Creator), Stern, C. L. (Creator), Wawrzak, Z. (Creator) & Pink, M. (Creator), Cambridge Crystallographic Data Centre, 2007
DOI: 10.5517/ccpdnj7, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccpdnj7&sid=DataCite
Dataset
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CCDC 637778: Experimental Crystal Structure Determination
Oliveri, C. G. (Creator), Gianneschi, N. (Creator), Nguyen, S. (Creator), Mirkin, C. A. (Creator), Stern, C. L. (Creator), Wawrzak, Z. (Creator) & Pink, M. (Creator), Cambridge Crystallographic Data Centre, 2007
DOI: 10.5517/ccpdnh6, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccpdnh6&sid=DataCite
Dataset