Journal
JOURNAL OF ORGANIC CHEMISTRY
Volume 72, Issue 19, Pages 7244-7252Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jo071106g
Keywords
-
Categories
Funding
- NIGMS NIH HHS [GM 58907] Funding Source: Medline
Ask authors/readers for more resources
[GRAPHICS] The macrocyclic receptors 4-6 were synthesized via the anion-templated condensation of appropriately chosen dialdehyde and diamine building blocks. Whereas all three products could be obtained directly via the appropriate choice of reaction conditions, the larger [3+3] product, 6, which incorporates three of each precursor subunit, could also be obtained conveniently via an indirect procedure involving ring expansion of the smaller [2+2] inacrocycle 4. As detailed earlier (Sessler, J. L.; Katayev, E. A.; Pantos, G. D.; Reshetova, M. D.; Khrustalev, V. N.; Lynch, V. M.; Ustynyuk, Y. A. Angew. Chem. 2005, 117, 7552-7556; Angew. Client., Int. Ed. 2005, 44, 7386-7390), this ring expansion occurs under thermodynamic control in the presence of HSO4- and H2PO4- anions in acetonitrile solution and serves to effect the conversion of 4 to 6. An analysis of the X-ray crystal structure of complex 6H(2)(2+)center dot HpO(4)(2-) revealed a strong resemblance to the active site of the phosphate binding protein (PBP) with similar structural analogies being drawn between the active site of the sulfate binding protein (SBP) and the corresponding hydrogensulfate anion complex. In both cases, the anions are bound in a 1:1 fashion in the solid state through a complementary hydrogen bond network involving both the receptor 6 and the anions. UV-vis spectroscopic titrations provide support for the conclusion that macrocycle 6 binds the hydrogensulfate and dihydrogerphosphate anion (studied as the corresponding tetrabutylammonium salts) with high selectivity and affinity in acetonitrile (log K-a for the first binding interaction approaching 7), albeit with different receptor-to-anion binding stoichiometries (1:1 vs 1:3 for HSO4- and H2PO4-, respectively).
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available