TRISPHAT (full name tris(tetrachlorocatecholato)phosphate(1−)) is an

inorganic In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemis ...

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

with the formula often prepared as the tributylammonium () or

tetrabutylammonium Tetrabutylammonium is a quaternary ammonium cation with the formula (C4H9)4sup>+. It is used in the research laboratory to prepare lipophilic salts of inorganic anions. Relative to tetraethylammonium derivatives, tetrabutylammonium salts are more ...

(

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quanti ...

. The anion features

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ea ...

(V) bonded to three tetrachlorocatecholate ()

ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's ele ...

s. This anion can be resolved into the axially chiral

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...

s, which are optically stable (the picture shows the Δ enantiomer). The TRISPHAT anion has been used as a

chiral shift reagent A chiral shift reagent is a reagent used in analytical chemistry for determining the optical purity of a sample. Some analytical techniques such as HPLC and NMR, in their most commons forms, cannot distinguish enantiomer In chemistry, an en ...

for

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s. It improves the resolution of ¹H NMR spectra by forming

diastereomeric In stereochemistry, diastereomers (sometimes called diastereoisomers) are a type of stereoisomer. Diastereomers are defined as non-mirror image, non-identical stereoisomers. Hence, they occur when two or more stereoisomers of a compound have di ...

ion pairs.

Preparation

The anion is prepared by treatment of

phosphorus pentachloride Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive and moist ...

with tetrachlorocatechol followed by a

tertiary amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent such ...

gives the anion: :PCl₅ + 3 C₆Cl₄(OH)₂ → H (O₂C₆Cl₄)₃ + 5 HCl :H (O₂C₆Cl₄)₃ + Bu₃N → Bu₃NH⁺ (O₂C₆Cl₄)₃sup>− Using a chiral amine, the anion can be readily resolved..

References

{{reflist Organophosphates Anions Chloroarenes Catechols Phosphates Nuclear magnetic resonance