Supramolecular Adducts of Ferrocene and Five Bile Acid Derived Triolides
✍ Scribed by Lappalainen, Kari ;Kolehmainen, Erkki
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 386 KB
- Volume
- 1997
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Abstract
Formation of supramolecular adducts of ferrocene (guest) and cyclic head‐to‐tail trimers (hosts) derived from bile acid: 3α‐hydroxy‐5β‐cholan‐24‐oic acid triolide (1), 3α‐hydroxy‐7‐oxo‐5β‐cholan‐24‐oic acid triolide (2), 3α‐hydroxy‐12‐oxo‐5β‐cholan‐24‐oic acid triolide (3), 3α‐hydroxy‐7α‐trifluoroacetoxy‐6β‐cholan‐24‐oic acid triolide (4) and 3α‐hydroxy‐12α‐TFA‐5β‐cholan‐24‐oic acid triolide (5) (TFA = trifluoroacetoxy) have been studied by ^1^H NMR. The best computer‐assisted data fitting on the ^1^H‐NMR chemical shift data was given by a 1:2 (guest/host) association model. The association constants vary in the range 170–990 M^−1^, 7‐oxo‐substituted triolide 2 and 12α‐TFA triolide 5 showing the largest and smallest values respectively. Generally, triolides bearing substituents at the position C‐7 (2 and 4), when compared with the 12‐substituted derivatives 3 and 5, seem to favour adduct formation, while a TFA group at the position C‐7 or C‐12 seems to hinder the adduct formation in comparison with the oxo‐substituted congeneers. This finding may be accounted for by the bulky character of the TFA group when compared to the oxo group.