Calixarenes calixspherands

Amalgamation of stmctural units typical of crowns and calixarenes has led to the development of calixpodands, calixcrowns, and calixspherands (55). Naturally they behave as cation complexants rather than iaclusion hosts for uncharged molecules. 

Numerous modifications of calixarenes, spherands and similar systems have been synthesized 241 [40], 242 [41], calixspherands like 243 [42] and torands like 244 [43] to name but a few pertaining interesting ligands. 

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