A Pseudorotaxane System Containing γ‐Cyclodextrin Formed via Chiral Recognition with an Au^I₆Ag^I₃Cu^II₃ Molecular Cap

Abstract

Solvent-mediated crystal-to-crystal transformations of [Au 6 Ag 3 Cu 3 (H 2 O) 3 (d-pen) 6 (tdmeto the replacement of a terminal aqua ligand in d-[1(H 2 O) 3 ] 3 + by a monodentate bdc 2À ligand. When γ-cyclodextrin (γ-CD) was added to aqueous Na 2 bdc, d-[1(H 2 O) 3 ] 3 + was transformed to d-[1(bdc@γ-CD)(H 2 O) 2 ] + , where a γ-CD ring was threaded by a bdc 2À molecule to construct a pseudorotaxane structure. While the use of dicarboxylates with an aliphatic carbon chain instead of bdc 2À afforded analogous pseudorotaxanes, such pseudorotaxane species were not formed when crystals of [Au 6 Ag 3 Cu 3 (H 2 O) 3 (lpen) 6 (tdme) 2 ] 3 + (l-[1(H 2 O) 3 ] 3 + ) enantiomeric to d-[1(H 2 O) 3 ] 3 + were soaked in aqueous Na 2 bdc and γ-CD, affording only crystals containing l-[1(bdc)(H 2 O) 2 ] + .