Dynamic aggregation of the mid-sized gadolinium complex {Ph4[Gd(DTTA)(H2O)2]− 3}
摘要:
A compound binding three Gd3+ ions, {Ph-4[Gd(DTTA)(H2O)(2)](-) (3)} (where H(5)DTTA is diethylenetriaminetetraacetic acid), has been synthesized around a hydrophobic center made up of four phenyl rings. In aqueous solution the molecules start to self-aggregate at concentrations well below 1 mM as shown by the increase of rotational correlation times and by the decrease of the translational self-diffusion constant. NMR spectra recorded in aqueous solution of the diamagnetic analogue {Ph-4[Y(DTTA)(H2O)(2)](-) (3)} show that the aggregation is dynamic and due to intermolecular pi-stacking interactions between the hydrophobic aromatic centers. From estimations of effective radii, it can be concluded that the aggregates are composed of two to three monomers. The paramagnetic {Ph-4[Gd(DTTA)(H2O)(2)](-) (3)} exhibits concentration-dependent H-1 NMR relaxivities with high values of approximately 50 mM(-1) s(-1) (30 MHz, 25 A degrees C) at gadolinium concentrations above 20 mM. A combined analysis of H-1 NMR dispersion profiles measured at different concentrations of the compound and O-17 NMR data measured at various temperatures was performed using different theoretical approaches. The fitted parameters showed that the increase in relaxivity with increasing concentration of the compound is due to slower global rotational motion and an increase of the Lipari-Szabo order parameter S-2.
A benzene-core trinuclear Gd<sup>III</sup>complex: towards the optimization of relaxivity for MRI contrast agent applications at high magnetic field
作者:João Bruno Livramento、Lothar Helm、Angélique Sour、Conlin O'Neil、André E. Merbach、Éva Tóth
DOI:10.1039/b717390c
日期:——
A novel ligand, H(12)L, based on a trimethylbenzene core bearing three methylenediethylenetriamine-N,N,N'',N''-tetraacetate moieties (-CH(2)DTTA(4-)) for Gd(3+) chelation has been synthesized, and its trinuclear Gd(3+) complex [Gd(3)L(H(2)O)(6)](3-) investigated with respect to MRIcontrastagent applications. A multiple-field, variable-temperature (17)O NMR and proton relaxivity study on [Gd(3)L(H(2)O)(6)](3-)
Process for the production of DTPA-tetraesters of terminal carboxylic
申请人:Schering Aktiengesellschaft
公开号:US05514810A1
公开(公告)日:1996-05-07
The invention relates to a process for the production of diethylenetriaminepentacarboxylic acid tetraesters of general formula I ##STR1## in which R.sup.1 and Z have different meanings.
该发明涉及一种制备通式I的双乙烯三胺五羧酸四酯的方法,其中R1和Z具有不同的含义。
Substituted DTPA monoamides of the central carboxylic acid group and
申请人:Schering Aktiengesellschaft
公开号:US05676923A1
公开(公告)日:1997-10-14
Diethylenetriaminepentaacetic acid monoamide derivatives, their complexes and complex salts, containing an element of atomic numbers 21-29, 31, 32, 39, 42-44, 49 or 57-83, pharmaceutical agents containing these compounds, their use as contrast media and process for their production.
Process for the production of DTPA-monoamides of the central carboxylic
申请人:Schering Aktiengesellschaft
公开号:US05679852A1
公开(公告)日:1997-10-21
A process for the production of of general formula I diethylenetriaminepentacarboxylic acid monoamide derivatives ##STR1## in which E.sup.1, E.sup.2 and Z have varying meanings.
Cascade polymer complexes, process for their production and pharmaceutical agents containing said complexes
申请人:Schering AG
公开号:US20020187101A1
公开(公告)日:2002-12-12
Cascade polymer complexes with at least 16 ions of an element of atomic numbers 20 to 29, 39, 42, 44 or 57-83, useful NMR or x-ray lymphography imaging.