DOTA (chelator)

DOTA

Names
IUPAC name 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid
Other names DOTA, DotA, tetraxetan
Identifiers
CAS Number	60239-18-1 N
3D model (JSmol)	Interactive image Interactive image
ChemSpider	108701 N
ECHA InfoCard	100.113.833
IUPHAR/BPS	5538
PubChem CID	121841
InChI InChI=1S/C16H28N4O8/c21-13(22)9-17-1-2-18(10-14(23)24)5-6-20(12-16(27)28)8-7-19(4-3-17)11-15(25)26/h1-12H2,(H,21,22)(H,23,24)(H,25,26)(H,27,28) N Key: WDLRUFUQRNWCPK-UHFFFAOYSA-N N InChI=1/C16H28N4O8/c21-13(22)9-17-1-2-18(10-14(23)24)5-6-20(12-16(27)28)8-7-19(4-3-17)11-15(25)26/h1-12H2,(H,21,22)(H,23,24)(H,25,26)(H,27,28) Key: WDLRUFUQRNWCPK-UHFFFAOYAO
SMILES O=C(O)CN(CC1)CCN(CC(=O)O)CCN(CC(=O)O)CCN1CC(=O)O C1CN(CCN(CCN(CCN1CC(=O)O)CC(=O)O)CC(=O)O)CC(=O)O
Properties
Chemical formula	C16H28N4O8
Molar mass	404.42 g·mol−1
Appearance	White crystalline solid
Hazards
GHS pictograms
GHS signal word	WARNING
GHS hazard statements	H315, H319, H335
GHS precautionary statements	P261, P305+351+338
Related compounds
Related compounds	Cyclen, EDTA
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (also known as DOTA) is an organic compound with the formula (CH₂CH₂NCH₂CO₂H)₄. The molecule consists of a central 12-membered tetraaza (i.e., containing four nitrogen atoms) ring. DOTA is used as a complexing agent, especially for lanthanide ions. Its complexes have medical applications as contrast agents and cancer treatments.

The acronym DOTA is shorthand for both the tetracarboxylic acid and its various conjugate bases. In the area of coordination chemistry, the tetraacid is called H₄DOTA and its fully deprotonated derivative is DOTA⁴⁻. Many related ligands are referred to using the DOTA acronym, although these derivatives are generally not tetracarboxylic acids or the conjugate bases.

DOTA is derived from the macrocycle known as cyclen. The four secondary amine groups are modified by replacement of the N-H centers with N-CH₂CO₂H groups. The resulting aminopolycarboxylic acid, upon ionization of the carboxylic acid groups, is a high affinity chelating agent for di- and trivalent cations. The tetracarboxylic acid was first reported in 1976. At the time of its discovery DOTA exhibited the largest known formation constant for the complexation (chelating) of Ca²⁺ and Gd³⁺ ions. Modified versions of DOTA were first reported in 1988 and this area has proliferated since.

As a polydentate ligand, DOTA envelops metal cations, but the denticity of the ligand depends on the geometric tendencies of the metal cation. The main applications involve the lanthanides and in such complexes DOTA functions as an octadentate ligand, binding the metal through four amine and four carboxylate groups. Most such complexes feature an additional water ligand, giving an overall coordination number of nine.

For most transition metals, DOTA functions as a hexadentate ligand, binding through the four nitrogen and two carboxylate centres. The complexes have octahedral coordination geometry, with two pendent carboxylate groups. In the case of [Fe(DOTA)]⁻, the ligand is heptadentate.