2003
High Thermodynamic Stability and Extraordinary Kinetic Inertness of Cu(II) Complexes with 1,4,8,11-Tetraazacyclotetradecane-1,8-bis(methylphosphonic acid): Example of a Rare Isomerism between Kinetically Inert Penta- and Hexacoordinated Cu(II) Complexes
KOTEK, Jan, Přemysl LUBAL, Petr HERMANN, Ivana CÍSAŘOVÁ, Ivan LUKEŠ et. al.Základní údaje
Originální název
High Thermodynamic Stability and Extraordinary Kinetic Inertness of Cu(II) Complexes with 1,4,8,11-Tetraazacyclotetradecane-1,8-bis(methylphosphonic acid): Example of a Rare Isomerism between Kinetically Inert Penta- and Hexacoordinated Cu(II) Complexes
Autoři
KOTEK, Jan (203 Česká republika), Přemysl LUBAL (203 Česká republika), Petr HERMANN (203 Česká republika, garant), Ivana CÍSAŘOVÁ (203 Česká republika), Ivan LUKEŠ (203 Česká republika), Tomáš GODULA (203 Česká republika), Ivona SVOBODOVÁ (203 Česká republika), Petr TÁBORSKÝ (203 Česká republika) a Josef HAVEL (203 Česká republika)
Vydání
Chemistry - A European Journal, Weinheim, WILEY-VCH Verlag, 2003, 0947-6539
Další údaje
Jazyk
angličtina
Typ výsledku
Článek v odborném periodiku
Obor
10406 Analytical chemistry
Stát vydavatele
Německo
Utajení
není předmětem státního či obchodního tajemství
Odkazy
Impakt faktor
Impact factor: 4.353
Kód RIV
RIV/00216224:14310/03:00007933
Organizační jednotka
Přírodovědecká fakulta
UT WoS
000180368600020
Klíčová slova anglicky
cyclam derivatives; kinetics ; macrocyclic ligands ; phosphonate ligands ; stability constants
Změněno: 26. 6. 2009 12:26, prof. RNDr. Přemysl Lubal, Ph.D.
Anotace
V originále
In an aqueous solution at room temperature, 1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylphosphonic acid) (H4L1) and CuII form a pentacoordinated (pc) complex, pc-[Cu(L1)]2-, exhibiting conformation I of the cyclam ring. At high temperature, the complex isomerises to a hexacoordinated isomer, trans-O,O-[Cu(L1)]2-, with a trans-III[Note ] conformation of the cyclam ring. In pc-[Cu(L1)]2-, four ring nitrogen atoms and one phosphonate oxygen atom are arranged around CuII 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(L1)]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) (H4L2), forms an analogous pentacoordinated complex, pc-[Cu(L2)]2-, at room temperature. However, the complex does not isomerise to the octahedral complex analogous to trans-O,O-[Cu(L1)]2-. Because of the high thermodynamic stability of pc-[Cu(L1)]2-, (log =25.40(4), 25 degrees of Celsius, I=0.1 mol dm-3 KNO3) and the formation of protonated species, CuII is fully complexed in acidic solution (-log [H+] ~ 3). Acid-assisted decomplexation of both of the isomers of [Cu(H2L1)] 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 1/2=19.7 min for pc-[Cu(H2L1)] and about seven months for trans-O,O-[Cu(H2L1)] for decomplexation in 5 M HClO4 at 25 degrees of Celsius. The mechanism of formation of pc-[Cu(L1)]2- is similar to those observed for other macrocyclic complexes.
Návaznosti
GA203/02/0493, projekt VaV |
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GA203/03/0168, projekt VaV |
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MSM 143100011, záměr |
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