Thermodynamic and kinetic study of copper(II) complexes with N-methylene(phenylphosphinic acid) derivatives of cyclen and cyclam

Lubal, Přemysl; Kývala, Mojmı́r; Hermann, Petr; Holubová, Jana; Rohovec, Jan; Havel, Josef; Lukeš, Ivan

doi:10.1016/s0277-5387(00)00586-6

Cited by 34 publications

(25 citation statements)

References 56 publications

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“…Anyway, it is known that Cu(II)-cyclam complexes are much less stable in acidic media [38,41,42], so that HNO 3 solutions at various concentrations have been tested as possible detection media applied to the same accumulation conditions (selected here as 2 min preconcentration from 1.0 Â 10 À6 M Cu(II) solution at pH 4.5). Some typical results are illustrated in Figure 2, where it appears that 0.01 M HNO 3 is not strong enough to enable Cu(II) desorption as no measurable stripping signal was observed.…”

Section: Factors Affecting the Detection Stepmentioning

confidence: 99%

Cyclam‐Functionalized Silica‐Modified Electrodes for Selective Determination of Cu(II)

et al. 2009

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Cyclam derivatives have been grafted via 1, 2 or 4 silylated arms to the surface of mesoporous silica and the resulting materials have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Cu(II). Sensitive and selective detection of the target analyte was achieved owing to the attractive binding properties of this macrocyclic ligand towards Cu(II) species. Various parameters likely to affect the preconcentration and detection steps have been studied, including pH of the accumulation medium, composition of the detection solution, structure and composition of the adsorbent, accumulation time, or presence of potentially interfering species. In particular, the effect of the number of silylated groups linking the macrocycle to the silica network on the sensor performance was discussed. After optimization, Cu(II) can be determined in a linear concentration range extending from 2 nM to 100 mM. The method was validated by reliable Cu(II) determination in tap water.

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Section: Factors Affecting the Detection Stepmentioning

confidence: 99%

Cyclam‐Functionalized Silica‐Modified Electrodes for Selective Determination of Cu(II)

et al. 2009

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“…[22±24] It was found that these two ligands contain two very basic ring nitrogen atoms [22,23] and are somewhat selective toward large metal ions. [17c] We studied the influence of the methyl(phenyl)phosphinic acid pendant arms on the ability of the 12-and 14-membered tetraazacycles to complex transtion-metal [25,26] and lanthanide ions. [27] Our investigation of Cu II complexes of the ligands shows their high thermodynamic stability, the reasonable kinetic inertness of [Cu(H 2 dotp Ph )], and the kinetic lability of [Cu(H 2 tetp Ph )] in acid-assisted decomplexation.…”

Section: Introductionmentioning

confidence: 99%

“…[27] Our investigation of Cu II complexes of the ligands shows their high thermodynamic stability, the reasonable kinetic inertness of [Cu(H 2 dotp Ph )], and the kinetic lability of [Cu(H 2 tetp Ph )] in acid-assisted decomplexation. [26] A comparison of complexation properties of macrocycles with acetic and phosphorus acid pendant arms has been reviewed recently. [28] To design hexadentate ligands suitable for the first-row transtion-metal ions, 1,8-diacetic derivatives of cyclam, H 2 L 4 and H 2 L 5 , were synthesized.…”

Section: Introductionmentioning

confidence: 99%

High Thermodynamic Stability and Extraordinary Kinetic Inertness of Copper(II) Complexes with 1,4,8,11‐Tetraazacyclotetradecane‐1,8‐bis(methylphosphonic acid): Example of a Rare Isomerism between Kinetically Inert Penta‐ and Hexacoordinated Copper(II) Complexes

Kotek

Lubal

Hermann

et al. 2002

Chemistry A European J

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In an aqueous solution at room temperature, 1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylphosphonic acid) (H(4)L(1)) and Cu(I) (I) form a pentacoordinated (pc) complex, pc-[Cu(L(1))](2-), exhibiting conformation I of the cyclam ring. At high temperature, the complex isomerises to a hexacoordinated isomer, trans-O,O-[Cu(L(1))](2-), with a trans-III conformation of the cyclam ring. In pc-[Cu(L(1))](2-), four ring nitrogen atoms and one phosphonate oxygen atom are arranged around Cu(I) (I) in a structure that is half-way between a trigonal bipyramid and a tetragonal pyramid, with one phosphonic acid group uncoordinated. In the trans-O,O-[Cu(L(1))](2-) isomer, the nitrogen atoms form a plane and the phosphonic acid groups are in a mutually trans configuration. A structurally very similar ligand, 4-methyl-1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylphosphonic acid) (H(4)L(2)), forms an analogous pentacoordinated complex, pc-[Cu(L(2))](2-), at room temperature. However, the complex does not isomerise to the octahedral complex analogous to trans-O,O-[Cu(L(1))](2-). Because of the high thermodynamic stability of pc-[Cu(L(1))](2-), (logbeta=25.40(4), 25 degrees C, I=0.1 mol dm(-3) KNO(3)) and the formation of protonated species, Cu(I) (I) is fully complexed in acidic solution (-log [H(+)] approximately 3). Acid-assisted decomplexation of both of the isomers of [Cu(H(2)L(1))] takes place only after protonation of both uncoordinated oxygen atoms of each phosphonate moiety and at least one nitrogen atom of the cycle. The exceptional kinetic inertness of both isomers is illustrated by their half-lives tau(1/2)=19.7 min for pc-[Cu(H(2)L(1))] and tau(1/2) about seven months for trans-O,O-[Cu(H(2)L(1))] for decomplexation in 5 M HClO(4) at 25 degrees C. The mechanism of formation of pc-[Cu(L(1))](2-) is similar to those observed for other macrocyclic complexes.

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“…Its lanthanide(III) complexes are kinetically inert but the rate of their formation is rather slow [24,25]; the complexes have a high affinity for calcified tissues [10,18,19,[26][27][28][29][30][31]. On the other hand, tetrakis(methylphosphinic acid) H 4 dota analoges (Chart 1; R 0 = H, Et) form complexes with lower stability constants than those of the parent ligand as they exhibit a lower overall basicity [32][33][34][35]. It was shown that other properties of their complexes (rate of complex formation and decomposition, hydrophilicity, biodistribution, etc.)…”

Section: Introductionmentioning

confidence: 99%

Chemical and biological evaluation of 153Sm and 166Ho complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid monoethylester) (H4dotpOEt)

Försterová

Jandurová

Marques³

et al. 2008

Journal of Inorganic Biochemistry

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Thermodynamic and kinetic study of copper(II) complexes with N-methylene(phenylphosphinic acid) derivatives of cyclen and cyclam

Cited by 34 publications

References 56 publications

Cyclam‐Functionalized Silica‐Modified Electrodes for Selective Determination of Cu(II)

Cyclam‐Functionalized Silica‐Modified Electrodes for Selective Determination of Cu(II)

High Thermodynamic Stability and Extraordinary Kinetic Inertness of Copper(II) Complexes with 1,4,8,11‐Tetraazacyclotetradecane‐1,8‐bis(methylphosphonic acid): Example of a Rare Isomerism between Kinetically Inert Penta‐ and Hexacoordinated Copper(II) Complexes

Chemical and biological evaluation of 153Sm and 166Ho complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid monoethylester) (H4dotpOEt)

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