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1.

001-es BibID:BIBFORM085312
Első szerző:André, João P.
Cím:H5dotasa (=(αRS)?α?(Carboxymethyl)?1,4,7,10?tetraazacyclododecane?1,4,7,10?tetraacetic Acid), an Asymmetrical Derivative of H4dota (=1,4,7,10?Tetraazacyclododecane?1,4,7,10?tetraacetic Acid) Substituted at One Acetate Pendant Arm: 1H?NMR and Potentiometric Studies of the Ligand and Its Lanthanide(III) Complexes / João P. André, Ernö Brücher, Robert Kiraly, Rui A. Carvalho, Helmut Mäcke, Carlos F. G. C. Geraldes
Dátum:2005
ISSN:0018-019X
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Helvetica Chimica Acta. - 88 : 3 (2005), p. 633-646. -
További szerzők:Brücher Ernő (1935-) (vegyész) Király Róbert Carvalho, Rui A. Mäcke, Helmut Geraldes, Carlos Frederico de Gusmão Campos
Pályázati támogatás:T038364
OTKA
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DOI
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2.

001-es BibID:BIBFORM006198
Első szerző:Kálmán Ferenc K. (vegyész)
Cím:Synthesis, potentiometric, kinetic, and NMR studies of 1,4,7,10-tetraazacyclododecane-1,7-bis(acetic acid)-4,10-bis(methylenephosphonic acid) (DO2A2P) and its complexes with Ca(II), Cu(II), Zn(II) and lanthanide(III) ions / Kalman, F. K., Baranyai, Z., Toth, I., Banyai, I., Kiraly, R., Brucher, E., Aime, S., Sun, X., Sherry, A. D., Kovacs, Z.
Dátum:2008
ISSN:0020-1669
Megjegyzések:A cyclen-based ligand containing trans-acetate and trans-methylenephosphonate pendant groups, H(6)DO2A2P, was synthesized and its protonation constants (12.6, 11.43, 5.95, 6.15, 2.88, and 2.77) were determined by pH-potentiometry and H-1 NMR spectroscopy. The first two protonations were shown to occur at the two macrocyclic ring N-CH2-PO32- nitrogens while the third and fourth protonations occur at the two phosphonate groups. In parallel with protonation of the two -PO32- groups, the protons from the NH+-CH2-PO32- are transferred to the N-CH2-COO- nitrogens. The stability constants of the Ca2+, Cu2+, and Zn2+ (ML, MHL, MH2L, and M2L) complexes were determined by direct pH-potentiometry. Lanthanide(III) ions (Ln(3+)) form similar species, but the formation of complexes is slow; so, "out-of-cell" pH-potentiometry (La3+, Eu3+, Gd3+, Y3+) and competitive spectrophotometry with Cu(II) ion (Lu3+) were used to determine the stability constants. By comparing the log K-ML values with those of the corresponding DOTA (H(4)DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and DOTP (H8DOTP = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylenephosphonic acid) complexes, the order DOTA < DO2A2P < DOTP was found for all the metal ion complexes examined here with the exception of the Ca2+ complexes, for which the order is reversed. The relaxivity of Gd(DO2A2P) decreases between pH 2 and 7 but remains constant in the pH range of 7 < pH < 12 (r(1) = 3.6 mM(-1) s(-1)). The linewiths of the O-17 NMR signals of water in the absence and presence of Gd(DO2A2P) (at pH = 3.45 and 8.5) between 274 and 350 K are practically the same, characteristic of a q = 0 complex. Detailed kinetic studies of the Ce3+ and Gd3+ complexes with DO2A2P showed that complex formation is slow and involves a high stability diprotonated intermediate Ln(H(2)DO2A2P)*. Rearrangement of the diprotonated intermediate into the final complex is an OH- assisted process but, unlike formation of Ln(DOTA) complexes, rearrangement of Ln(H(2)DO2A2P)* also takes place spontaneously likely as a result of transfer of one of the protons from a ring nitrogen to a phosphonate group. The order of the OH- assisted formation rates of complexes is DOTA > DO2A2P > DOTP while the order of the proton assisted dissociation rates of the Gd3+ complexes is reversed, DOTP > DO2A2P > DOTA. H-1 and C-13 NMR spectra of Eu(DO2A2P) and Lu(DO2A2P) were assigned using two-dimensional correlation spectroscopy (2D COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear chemical shift correlation (HETCOR), and exchange spectroscopy (EXSY) NMR methods. Two sets of H-1 NMR signals were observed for Eu(DO2A2P) characteristic of the presence of two coordination isomers in solution, a twisted square antiprism (TSAP) and a square antiprism (SAP), in the ratio of 93% and 7%, respectively. Line shape analysis of the H-1 NMR spectra of Lu(DO2A2P) gave lower activation parameters compared to La(DOTP) for interconversion between coordination isomers. This indicates that the Ln(DO2A2P) complexes are less rigid probably due to the different size and spatial requireents of the carboxylate and phosphonate groups.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Inorganic Chemistry. - 47 : 9 (2008), p. 3851-3862. -
További szerzők:Baranyai Zsolt (1977-) (vegyész) Tóth Imre (1950-) (vegyész) Bányai István (1953-) (vegyész) Király Róbert Brücher Ernő (1935-) (vegyész) Aime, Silvio Sun, Xiankai Sherry, A. Dean Kovács Zoltán
Internet cím:elektronikus változat
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3.

001-es BibID:bibEBI00020634
035-os BibID:bibEBI00020633
Első szerző:Király Róbert
Cím:Aminopolycarboxilates of rare earths, 14. equilibrum and ¹H-NMR studies on the lanthanide-/III/-ethylebenis/exiethylenedinitrilo/ tetraacetate complexes / Király Róbert, Brücher Ernő
Dátum:1985
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Journal of the Less-Common Metals. - 109 (2007), p. 111-116. -
További szerzők:Brücher Ernő (1935-) (vegyész)
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4.

001-es BibID:BIBFORM067445
Első szerző:Nagy Nóra Veronika
Cím:Copper(II) complexes of some N-substituted bis(aminomethyl)phosphinate ligands : An integrated EPR study of microspeciation and coordination modes by the two-dimensional simulation method / Nóra Veronika Nagy, Terézia Szabó-Plánka, Gyula Tircsó, Róbert Király, Zsuzsanna Árkosi, Antal Rockenbauer, Ernő Brücher
Dátum:2004
ISSN:0162-0134
Megjegyzések:Copper(II) complexes of bis(aminomethyl)phosphinic acid (L1), bis(N-glycino-N-methyl)phosphinic acid (L2), bis(N-benzylglycino-N-methyl)phosphinic acid (L3), bis(l-prolino-N-methyl)phosphinic acid (L4) and bis(iminodicarboxymethyl-N-methyl)phosphinic acid (L5) were studied in aqueous solution by pH-potentiometric and electron paramagnetic resonance (EPR) spectroscopic methods. The EPR spectrum packages recorded at various ligand-to-metal concentration ratios and pH's were analyzed (after matrix rank analysis by the method of residual intensities as a complementary method) by the two-dimensional computer simulation method, which simultaneously determines the formation constants and the EPR parameters of the various (micro)species. L1 forms mono and bis complexes in different protonation states; for the other ligands, the mono complexes are always prevalent. For steric reasons, the formation of CuL is shifted to increasingly higher pH regions in the sequence L2, L3 and L4. CuLH was identified for L3, L4 and L5, and also CuLH2 for L4 and L5. Cu2L2 was found in small amounts for L3 and L4, while it predominates at pH > 4 for L5. For L5, Cu2L2H2 was also detected. For the ligands that form dimeric metal complexes in equimolar solution or at a ligand excess, Cu2L is formed at a metal ion excess. Ligation of the phosphinate O was suggested by indirect proofs in the protonated complexes of L1. For the ligands L2, L3 and L4, the copper(II) coordination in various species in different protonation states is reminiscent of that in the mono and bis complexes of simple amino acids. For the bis(aminomethyl)phosphinates, however, the cis positions of the amino groups in CuL are ensured by the structure of the ligand, and the isomers differ from each other in the (equatorial or axial) position of the second carboxylate group.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Electron paramagnetic resonance
Copper(II) complexes
N-Substituted bis(aminomethyl)phosphinic acids
Microspeciation
Coordination modes
Megjelenés:Journal of Inorganic Biochemistry 98 : 11 (2004), p. 1655-1666. -
További szerzők:Szabó-Plánka Terézia Tircsó Gyula (1977-) (vegyész, kémia tanár) Király Róbert Árkosi Zsuzsanna Rockenbauer, Antal Brücher Ernő (1935-) (vegyész)
Pályázati támogatás:T-032929
OTKA
T-038364
OTKA
T-046953
OTKA
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DOI
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5.

001-es BibID:bibKLT00005007
Első szerző:Tóth Éva (koordinációs kémia)
Cím:Equilibrium and kinetic studies on complexes of 10-[2,3-dihydroxy-(1-hydroxymethyl)-propyl]-1,4,7,10-tetraazacyclododecane-1,4,7-triacetate / É. Tóth, R. Király, J. Platzek, B. Radüchel, E. Brücher
Dátum:1996
Tárgyszavak:idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Inorganica Chemica Acta, 249 : 2 (1996), p. 191-199.
További szerzők:Király Róbert Platzek, Johannes Radüchel, Bernd Brücher Ernő (1935-) (vegyész)
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