Metal‐Organic Coordination Polymers Formed from γ‐Cyclodextrin and Divalent Metal Ions

The chemistry of metal‐organic frameworks based on cyclodextrins and alkali metals has been extensively investigated in recent years, but coordination polymers with non‐alkali metals have been rarely reported. Here, we describe the synthesis and X‐ray crystallographic characterization of a series of coordination polymers, [Ba(H 2 O) 3 (γ‐CD)]Cl 2 · 6H 2 O ( γ‐CD‐Ba1 ), [Ba(H 2 O)(γ‐CD)]Cl 2 · 8H 2 O ( γ‐CD‐Ba2) , [Sr(H 2 O)(γ‐CD)](NO 3 ) 2 · 9H 2 O ( γ‐CD‐Sr ), [Ca(γ‐CD) 2 ]Cl 2 · 2CH 3 OH · 16H 2 O ( γ‐CD‐Ca) , and [Pb(H 2 O)(γ‐CD)](NO 3 ) 2 · 11H 2 O ( γ‐CD‐Pb ), which were obtained by reacting γ‐cyclodextrin with alkaline earth metal ions and Pb 2+ . The coordination polymers formed from γ‐cyclodextrin and Ca 2+ and Ba 2+ are obtained for the first time. The only compound in the studied series, γ‐CD‐Ba1 , has a 3D structure. The other compounds have layered structures. In the structure of γ‐CD‐Ca , the coordination and number of γ‐cyclodextrin molecules connected to the Ca 2+ are different from those determined for a series of isostructural 2D coordination polymers, namely, γ‐CD‐Ba2 , γ‐CD‐Sr and γ‐CD‐Pb . The metal‐organic coordination polymer γ‐CD‐Pb exhibits photoluminescence in the near UV‐region (λ max = 345 nm).