Cavitand tetratopic

Scheme 7.12 Self-assembly of tetratopic Pd/Pt complex 52 and the other two possible cyclic structures. In the top views sketched in the scheme each sphere corresponds to two cavitands, one over the other.

Allosteric behavior in a ditopic cavitand receptor has been induced via metal coordination [62]. Addition of Ag+ ions to a solution of a 2,2 -bipyridine-bridged biscavitand 56 switches the molecule from an S-shaped to a C-shaped conformation with the two cavities facing each other. At the same time two bis-cavitand molecules are brought together to give an overall tetratopic complex 57 (Figure 7.24). 

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