Diaminocyclohexanetetraacetate

The kinetic parameters for the reaction between the Mn(III) complex with EDTA and the Mn(II) complex with rra/ji-l,2-diaminocyclohexanetetraacetate have recently been reported by Wilkins and Yelin as 1.2 l.mole sec S 7.1 kcal.mole and — 34 cal.deg mole . ... 

Baybarz, R. D. (1966). Dissociation constants of the transplutonium element chelates of l,2,diaminocyclohexanetetraacetic acid, J. Inorg. Nucl. Chem 28, 1055. 

Another class of Mn( III) complexes involves the polyaminocarboxylic acid ligands. The earliest study appeared in 1962 ( 44) and was followed shortly by studies of the cyclohexane analog of EDTA as well as other derivatives of EDTA (45). A recent paper discusses the reactivity of the manganese (III )-diaminocyclohexanetetraacetate complex with hydrogen peroxide (46). A mechanism is proposed which involves complexation by the peroxide anion followed by subsequent electron transfer to produce the Mn(II) complex and the H02 radical. The results are interesting and indicate the potential for selective catalysis by the higher oxidation state manganese complexes. 

An analysis of the time course of luminescence emission following selective laser excitation has enabled the forward and reverse rate constants to be obtained for the equilibrium between the Eu" complex of 1,2-diaminocyclohexanetetraacetate, [Eu(DCTA)], and iminodiacetate, IMDA, to form the ternary complex [Eu(DCTA)(IMDA)] . Some other systems in which chemical interconversion processes occur at rates much greater than, or much slower than, the reciprocal excited-state lifetime of the Eu" -containing species were also examined. A matrix isolation e.s.r. study has appeared of the photoreduction of the formato-complex of Eu " in a formic acid-sodium formate buffer. A three-step cyclic scheme has been suggested to explain the observations, namely photoreduction of by Eu, radical alternation from H to C02 , and oxidation of CO2 by Eu ". ... 

Figure 5. Variation of rate constants for the autoxidation of ascorbic acid as a function of concentration of Fe(III) chelates at 25°C and —log [H ] of 2.45 DTPA = diethylenetriaminepentaacetic acid CDTA = trsins l,2-diaminocyclohexanetetraacetic acid other terms as in caption of...

CDTA trans-l,2,-diaminocyclohexanetetraacetic acid chelidamic (l,4-dihydro-4-oxo-2, 6-pyridine-dicarboxylic) acid... 

Among many ligands used for simultaneous ion chromatography of metals, the most common eluents used are oxalic acid, tartaric acid, citric acid, 4-(2-pirydylazo)resorcinol (PAR), pyridine-2,6-dicarboxylic acid (PDCA), a-hydroxyi-sobutyric acid (HIBA), 1,2-diaminocyclohexanetetraacetic acid (DCTA), diethylenetriarninepentaacetic acid (DTPA), and ethylenediaminetetraacetic acid (EDTA). 

Figure 8 Formation constants of Ln with some aminocarboxylic acids. DCTA, 1,2-diaminocyclohexanetetraacetic acid EDTA, ethylenediaminetetraacetic acid EGTA, l,2-bis(di(carboxymethyl)aminoethoxy)ethane...

Briicher E. P. Szarvas, Kinetic study of the isotope-exchange reactions of the central ions of the lanthanide ethylenediaminetetraacetate and trans-l,2-diaminocyclohexanetetraacetate complexes. Inorg. Chim. Acta 4, 632—636 (1970). 

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