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RESEARCH PRODUCT

Supramolecular Adducts of Ferrocene and Five Bile Acid Derived Triolides

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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 1H NMR. The best computer-assisted data fitting on the 1H-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.