In chemistry, a cavitand is a container-shaped

molecule A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

. The cavity of the cavitand allows it to engage in

host–guest chemistry In supramolecular chemistry, host–guest chemistry describes complexes that are composed of two or more molecules or ions that are held together in unique structural relationships by forces other than those of full covalent bonds. Host–guest ch ...

with guest molecules of a complementary shape and size. The original definition proposed by

Cram Cram may refer to: * Cram (surname), a surname, and list of notable persons having the surname * Cram.com, a website for creating and sharing flashcards * Cram (Australian game show), a television show * ''Cram'' (game show), a TV game show that ...

includes many classes of molecules: cyclodextrins,

calixarene 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 Cal ...

s, pillararenes and

cucurbituril In host-guest chemistry, cucurbiturils are macrocyclic molecules made of glycoluril () monomers linked by methylene bridges (). The oxygen atoms are located along the edges of the band and are tilted inwards, forming a partly enclosed cavity ( ...

s. However, modern usage in the field of

supramolecular chemistry Supramolecular chemistry refers to the branch of chemistry concerning chemical systems composed of a discrete number of molecules. The strength of the forces responsible for spatial organization of the system range from weak intermolecular forces ...

specifically refers to cavitands formed on a

resorcinarene In chemistry, a resorcinarene (also resorcarene or calix esorcinarene) is a macrocycle, or a cyclic oligomer, based on the condensation of resorcinol (1,3-dihydroxybenzene) and an aldehyde. Resorcinarenes are a type of calixarene. Other types of ...

scaffold by bridging adjacent phenolic units. The simplest bridging unit is methylene (), although dimethylene (), trimethylene (), benzal,

xylyl In organic chemistry, xylene or xylol (; IUPAC name: dimethylbenzene) are any of three organic compounds with the formula . They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are sub ...

, pyridal, 2,3-disubstituted-quinoxaline, ''o''-dinitrobenzyl, dialkylsilydine, and

phosphonate In organic chemistry, phosphonates or phosphonic acids are organophosphorus compounds containing groups (where R = alkyl, aryl, or just hydrogen). Phosphonic acids, typically handled as salts, are generally nonvolatile solids that are poorly ...

s are known. Cavitands that have an extended aromatic bridging unit, or an extended cavity containing 3 rows of aromatic rings are referred to as deep-cavity cavitands and have broad applications in host-guest chemistry. These types of cavitands were extensively investigated by Rebek, and

Gibb Gibb is a surname of Scottish origin dating to the sixteenth century. It is a diminutive of " Gilbert". Notable people with the given name * Andrew Gibb Maitland (1864–1951), English-born Australian geologist * Gibb McLaughlin (1884–1960), ...

, among others.

Applications of Cavitands

Specific cavitands form the basis of rigid templates onto which '' de novo'' proteins can be chemically linked. This ''template assembled synthetic protein'' (TASP) structure provides a platform for the study of

protein structure Protein structure is the three-dimensional arrangement of atoms in an amino acid-chain molecule. Proteins are polymers specifically polypeptides formed from sequences of amino acids, the monomers of the polymer. A single amino acid monom ...

. Silicon surfaces functionalized with tetraphosphonate cavitands have been used to singularly detect

sarcosine Sarcosine, also known as ''N''-methylglycine, or monomethylglycine, is a monopeptide with the formula CH3N(H)CH2CO2H. It exists at neutral pH as the zwitterion CH3N+(H)2CH2CO2−, which can be obtained as a white, water-soluble powder. Like som ...

in water and

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

solutions.

References

{{Reflist Supramolecular chemistry Chelating agents

Applications of Cavitands

See also

References