calixarene

{{Quote box|width = 35% |title = IUPAC definition |quote = calixarenes: Originally macrocyclic compounds capable of assuming a basket (or 'calix') shaped conformation. They are formed from p-hydrocarbyl phenols and formaldehyde. The term now applies to a variety of derivatives by substitution of the hydrocarbon cyclo{oligo(1,3-phenylene)methylene}. }} A calixarene is a macrocycle or cyclic oligomer based on a methylene-linked phenols. With hydrophobic cavities that can hold smaller molecules or ions, calixarenes belong to the class of cavitands known in host–guest chemistry.

==Nomenclature== Calixarene nomenclature is straightforward and involves counting the number of repeating units in the ring and including it in the name. A calix[4]arene has 4 units in the ring and a calix[6]arene has 6. A substituent in the meso position Rb is added to the name with a prefix C- as in C-methylcalix[6]arene The word calixarene is derived from the Greek calix or chalice because this type of molecule resembles a vase (or cup) and from the word arene that refers to the aromatic building block.