chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

, a cavitand is a container-shaped

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

. The cavity of the cavitand allows it to engage in

host–guest chemistry In supramolecular chemistry, host–guest chemistry describes inclusion compound, 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 bo ...

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 ...

includes many classes of molecules:

cyclodextrins Cyclodextrins are a family of cyclic oligosaccharides, consisting of a macrocyclic ring of glucose subunits joined by α-1,4 glycosidic bonds. Cyclodextrins are produced from starch by enzymatic conversion. They are used in food, pharmaceuti ...

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 ...

pillararene Pillararenes are macrocycles composed of hydroquinone or dialkoxybenzene units (5 to 10) linked in the Para isomer, para position by methylene bridges. They are structurally similar to the cucurbiturils and calixarenes that play an important part i ...

s 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 species, chemical systems composed of a integer, discrete number of molecules. The strength of the forces responsible for spatial organization of the system range from w ...

specifically refers to cavitands formed on a

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

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 ...

pyridyl Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom . It is a highly flammable, weakly alkaline, water-miscible liquid with a ...

, 2,3-disubstituted-quinoxaline, ''o''-dinitrobenzyl, dialkylsilylene, and

phosphonate In organic chemistry, phosphonates or phosphonic acids are organophosphorus compounds containing Functional group, groups, where R is an organic group (alkyl, aryl). If R is hydrogen then the compound is a Phosphite_ester#Chemistry_of_HP(O)(OR ...

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 De novo (Latin, , used in English to mean 'from the beginning', 'anew') may refer to: Science and computers * ''De novo'' mutation, a new germline mutation not inherited from either parent * ''De novo'' protein design, the creation of a protei ...

'' 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, which are the monomers of the polymer. A single amino acid ...

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

sarcosine Sarcosine, also known as ''N''-methylglycine, or monomethylglycine, is a amino acid 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 some ...

in water and

urine Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...

solutions.

References

{{Reflist Supramolecular chemistry Chelating agents

Applications of Cavitands

See also

References