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@article{390689,
author = {Lubal, Přemysl and Kývala, M. and Hermann, P. and Holubová, J. and Rohovec, J. and Havel, Josef and Lukeš, Ivan},
article_location = {Oxford},
article_number = {1-2},
keywords = {Polyazamacrocycles; phosphinic acids; cyclen and cyclam derivatives; copper(II) complexes; potenciometry; kinetics; stability constants},
language = {eng},
issn = {0277-5387},
journal = {Polyhedron},
title = {Thermodynamic and kinetic study of copper(II) complexes with N-methylene(phenylphosphinic acid) derivatives of cyclen and cyclam},
volume = {20},
year = {2001}
}
TY - JOUR
ID - 390689
AU - Lubal, Přemysl - Kývala, M. - Hermann, P. - Holubová, J. - Rohovec, J. - Havel, Josef - Lukeš, Ivan
PY - 2001
TI - Thermodynamic and kinetic study of copper(II) complexes with N-methylene(phenylphosphinic acid) derivatives of cyclen and cyclam
JF - Polyhedron
VL - 20
IS - 1-2
SP - 47-55
EP - 47-55
PB - Pergamon-Elsevier Science
SN - 02775387
KW - Polyazamacrocycles
KW - phosphinic acids
KW - cyclen and cyclam derivatives
KW - copper(II) complexes
KW - potenciometry
KW - kinetics
KW - stability constants
N2 - Equilibria in the Cu2+-H4L1 and Cu2+-H4L2 systems, where H4L1 is 1,4,7,10-tetraaza-cyclododecane-1,4,7,10-tetrayl-tramethylene-tetrakis(phenylphosphinic acid) and H4L2 is 1,4,8,11-tetraaza-cyclotetradecane-1,4,8,11-tetrayl-tetramethylene-tetrakis(phenylphosphinic acid), were investigated by glass electrode potentiometry at 25 degreesC (I = 0.1 mol dm(-3) KNO3). A simple chemical model with the metal:ligand molar ratio 1:1 was found in the systems. The presence of main species, [CuL1](2-)(log beta = 20.37(4)) and [CuL2](2-) (log beta = 17.19(2)), was also confirmed by MALDI-TOF/MS. The dissociation kinetics of the complexes was followed by spectrophotometry and a mechanism of the dissociation was proposed. Activation parameters (activation enthalpy and entropy) of the dissociation were estimated. For the Cu2+ -H4L1 system, the complex dissociation starts after protonation of the phosphinic pendant arms and its mechanism is similar to the decomplexation of [Cu(cyclen)](2+). The Cu2+ complex with H4L2 is kinetically much less stable. The proton transfer from the phosphinic pendant arm to the azacycle plays a significant role in the reaction mechanism of both the complexes.
ER -
LUBAL, Přemysl, M. KÝVALA, P. HERMANN, J. HOLUBOVÁ, J. ROHOVEC, Josef HAVEL and Ivan LUKEŠ. Thermodynamic and kinetic study of copper(II) complexes with N-methylene(phenylphosphinic acid) derivatives of cyclen and cyclam. \textit{Polyhedron}. Oxford: Pergamon-Elsevier Science, 2001, vol.~20, 1-2, p.~47-55. ISSN~0277-5387.
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