Study of Copper(II) Polyazamacrocyclic Complexes by Electronic Absorption Spectrophotometry and EPR Spectroscopy

Geraldes, Carlos F. G. C.; Marques, M. P. M.; Castro, Baltazar de; Pereira, Eulalia F.

doi:10.1002/(sici)1099-0682(200003)2000:3<559::aid-ejic559>3.0.co;2-j

Cited by 35 publications

(27 citation statements)

References 36 publications

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“…The stability constant of Cu(II)-DOTP measured here (26.2±0.2) is about the same as the value previously reported (25.4) [13,34]. The stability constants of Cu(II)-DO2P and Cu(II)-DO3P are 28.7±0.3 and 26.9±0.2, respectively.…”

Section: Protonation and Stability Constantssupporting

confidence: 90%

“…By electronic absorption spectrophotometry and electron paramagnetic resonance (EPR) spectroscopy, the solution structure of the Cu(II)-DOTP complex was recently determined to be a square-pyramidal geometry with four ring-nitrogen atoms defining the equatorial plane, while the axial position is probably occupied by an oxygen from one methanephosphonate side-arm [34]. This structure is similar to the solid state structure of the Cu(II) complex with a similar ligand, N,N¢,N¢¢,N¢¢¢-tetrakis[2-(diphenylphosphoryl)ethyl]-1,4,7,10-tetraazacyclododecane [35].…”

Section: Introductionmentioning

confidence: 74%

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In vivo behavior of copper-64-labeled methanephosphonate tetraaza macrocyclic ligands

et al. 2003

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Copper-64 ( T(1/2)=12.7 h; beta(+): 0.653 MeV, 17.4%; beta(-): 0.578 MeV, 39%) is produced in a biomedical cyclotron and has applications in both imaging and therapy. Macrocyclic chelators are widely used as bifunctional chelators to bind copper radionuclides to antibodies and peptides owing to their relatively high kinetic stability. In this paper, we evaluated three tetraaza macrocyclic ligands with two, three, and four pendant methanephosphonate functional groups. DO2P [1,4,7,10-tetraazacyclododecane-1,7-di(methanephosphonic acid)], DO3P [1,4,7,10-tetraazacyclododecane-1,4,7-tri(methanephosphonic acid)], and DOTP [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methanephosphonic acid)] were all radiolabeled with (64)Cu in high radiochemical yields. Copper-64-labeled DO2P and DOTP were highly stable in rat serum out to 24 h, while (64)Cu-DO3P remained 73% intact, with the remainder possibly forming a (64)Cu(.)2DO3P dimer by 24 h. The biodistribution experiments were performed in normal Sprague-Dawley rats. Of the three complexes, (64)Cu-DO2P demonstrated the most optimal clearance through the blood and liver. Copper-64-DO3P and (64)Cu-DOTP exhibited higher liver uptake and longer retention of liver activity, possibly because of the large negative charge of the complexes under physiological conditions. All three (64)Cu-labeled complexes showed high accumulation in bone, likely due to the binding of the methanephosphonate groups to hydroxyapatite. These results suggest that this series of methanephosphonate macrocyclic ligands may be useful as potential bone-imaging agents. The thermodynamic stability constants of the Cu(II) complexes with these three ligands were determined, and were found to be significantly higher than those of their acetate analogues. The Cu(II)-DO2P complex exhibited the highest stability constant among divalent transition metal ion DO2P complexes. Metabolism studies of (64)Cu-DO2P in rat liver suggest that the DO2P ligand may be used as a bifunctional chelator for copper radionuclides in radiodiagnostic or radiotherapeutic studies.

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Section: Protonation and Stability Constantssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 74%

In vivo behavior of copper-64-labeled methanephosphonate tetraaza macrocyclic ligands

et al. 2003

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“…Since the liver is the anatomical location of copper metabolism, the stability of the copper chelate in a 64 Cu-containing radiopharmaceutical under physiological conditions is very important (Wadas et al, 2007). Increasing the stability of copper complexes in vivo has been a major focus in the field of nuclear medicine for some time (Di Bartolo et al, 2001 andGasser et al, 2008;Kukis et al, 1993;Voss et al, 2007;Pippin et al, 1991;Geraldes et al, 2000;Wieghardt et al, 1982;van der Merwe et al, 1985;Soluri et al, 2003;Maina et al, 2005;Monstein et al, 2006;Sun & Chen, 2007) as the development of stable copper complexes will allow for a variety of copper-based diagnostic and therapeutic strategies. Recent work in the field of copper radiochemistry has produced very promising results.…”

Section: Micropet Imaging With Copper-64-bbn Conjugatesmentioning

confidence: 99%

“…Recently, we have reported on the superior microPET imaging quality of NOTA bifunctional chelator over that of the DOTA using 64 Cu in a GRPR-positive human prostate cancer mouse model . Previous investigations have reported a highly stable complex consisting of NOTA and divalent copper (Kukis et al, 1993;Geraldes et al, 2000;Wieghardt et al, 1982). Also reported are biomolecules conjugated with NOTA and chelating 64 Cu.…”

Section: Micropet Imaging With Copper-64-bbn Conjugatesmentioning

confidence: 99%

Molecular Imaging of Breast Cancer Tissue via Site-Directed Radiopharmaceuticals

Jackson¹,

Retzloff²,

Nanda³

et al. 2011

Breast Cancer - Recent Advances in Biology, Imaging and Therapeutics

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“…The EPR parameters for Cu(II) complexes are determined by the chemical composition and the geometry of the atoms nearest to the metal ion. The significant increase in the axial ligand field in this complex is most probably reflected in the measured values of the hyperfine coupling constants, which are much smaller than the values of A found for six-coordinate complexes of distorted octahedral geometry, such as the bis(pyridine-2,6-diimine) Cu(II) complex (A =145 × 10 − 4 cm − 1 ), with six nitrogen atoms in the coordination sphere [11], or the [Cu(NOTA)] − complex (NOTA =1,4,7-triazacyclononane-1,4,7-triacetate) (A =149.5 × 10 − 4 cm − 1 ), with three nitrogen and tree oxygen atoms in the coordination sphere [12].…”

Section: Epr Spectroscopymentioning

confidence: 99%

Copper complexes with bibracchial lariat ethers: from mono- to binuclear structures

Rodrı́guez-Infante

Esteban‐Gómez

Avecilla

et al. 2001

Inorganica Chimica Acta

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Copper(II) complexes with a series of bibracchial lariat ethers are described. Independently of the nature of the counterion present (nitrate or perchlorate), the lariat ether N, N%-bis(2-aminobenzyl)-1,10-diaza-15-crown-5 (L 1 ) always forms mononuclear complexes, whereas the lariat ethers N, N%-bis(2-aminobenzyl)-4,13-diaza-18-crown-6 (L 2 ) and N,N%-bis(2-salicylaldiminobenzyl)-4,13-diaza-18-crown-6 (L 3 ) only give binuclear compounds. The X-ray crystal structure of [CuL 1 ](ClO 4 ) 2 shows a seven-coordinated copper(II) ion in a distorted (axially compressed) pentagonal-bipyramidal geometry. The X-ray crystal structure of [Cu 2 (L 3 -2H)](ClO 4 ) 2 confirms the binuclear nature of the compound with both metal ions having identical coordination environments and each one placed out of the crown hole but efficiently encapsulated by the corresponding pendant arm; each copper(II) ion is five-coordinated with an intermediate geometry between trigonal-bipyramidal and square-pyramidal (~= 0.40). The EPR spectra in frozen solution samples are in accordance with a stable coordinate pattern for the metal centre of ligand L 1 , yielding a rhombic distorted complex with axial compression in solution, in agreement with the X-ray crystal structure of [CuL 1 ](ClO 4 ) 2 . For the binuclear complexes of L 2 and L 3 , the Cu(II) centres in solution can be distorted from their tetragonally elongated structures via interaction with ethanol and/or the nitrate counterion, leading to more than one species.

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Study of Copper(II) Polyazamacrocyclic Complexes by Electronic Absorption Spectrophotometry and EPR Spectroscopy

Cited by 35 publications

References 36 publications

In vivo behavior of copper-64-labeled methanephosphonate tetraaza macrocyclic ligands

In vivo behavior of copper-64-labeled methanephosphonate tetraaza macrocyclic ligands

Molecular Imaging of Breast Cancer Tissue via Site-Directed Radiopharmaceuticals

Copper complexes with bibracchial lariat ethers: from mono- to binuclear structures

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