ISSN:
0009-2940
Keywords:
Crown compounds / Host-guest chemistry / Macropentacyclic compounds / Phanes / Supramolecular chemistry
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Pentamacrocyclic Tris-Crown Hosts. - Selective Binding of Cationic, Anionic, and Neutral Guest CompoundsThe tris-crown host compounds 1-4 were synthesized for the first time. The X-ray crystal structures of 2 and of the 1:3 complex of 1 and KSCN were determined. Whereas in the free crown 2 a less well preorganized molecular cavity is encountered, in the complex of 1 with KSCN one potassium ion is bound to each crown ether unit. One of the three SCN- anions is situated in the interior of the cavity and in addition is disordered in such a way as to be bound to the K+ using partially the S atom of the SCN- ion. Organic guest molecules like 1,2-, 1,3-, 1,5-, 2,6-, and 2,7-naphthalenediol as well as β-naphthol in acidic water solution are bound selectively in the interior of the cavities of the host molecules 2 and 3, but not by 1 and 4, the cavities of which seem to be too small and too large, respectively. In contrast, the binding of α-naphthol and of smaller phenolic guest molecules like phenol, resorcinol, pyrocatechol, phloroglucinol, pyrogallol, and 1,2,4-trihydroxy-benzene with the host 1-4 is much less pronounced (1H- NMR highfield shifts).
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230435
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