Complexes of tetraazacycles bearing methylphosphinic/phosphonic acid pendant arms with copper(II), zinc(II) and lanthanides(III). A comparison with their acetic acid analogues

Lanthanide(III) Complexes of 4,10‐Bis(phosphonomethyl)‐1,4,7,10‐tetraazacyclododecane‐1,7‐diacetic acid (trans‐H6do2a2p) in Solution and in the Solid State: Structural Studies Along the Series

“…Such a protonation is caused by an increase of the electronic density on the amine groups due to spreading of the negative charge of the mono-protonated phosphonate groups. Such behaviour is common for a-amino phosphonic acids, [35] and this mode of protonation has been also observed for the zwitterionic form of H 5 do3ap (Scheme 1) in the solid state. [36] The two remaining protons are bound to the oxygen atoms of the two carboxylic groups, which are attached to the non-protonated nitrogen atoms.…”

A Triazacyclononane‐Based Bifunctional Phosphinate Ligand for the Preparation of Multimeric 68Ga Tracers for Positron Emission Tomography

“…Also, PrP9 fits into the correlation of overall basicity of these ligands with the stability constants of their Cu II and Zn II complexes. [30] The distribution diagram ( Figure 3) shows that the 1:1 complex is triply negatively charged under physiological pH. In solutions containing two equivalents of Ga 3 + , the primary complex appears to be able to bind an additional Ga 3 + ion, most likely by weak interaction with the side-arm carboxA C H T U N G T R E N N U N G yl-A C H T U N G T R E N N U N G ates and/or the phosphoryl oxygen atoms (that is, in the form of an "out-of-cage" complex).…”

“…In the case of Ga 3 + ("equilibrium" titration) and Gd 3 + ions, the complexation was too slow for a conventional titration. Thus the "out-of-cell" method was used: 30 ] in each tube/ampoule for out-of-cell titration was measured separately with a freshly calibrated electrode (as given below). The constants determined by this technique showed higher standard deviations due to less precise measurements and a smaller number of experimental points.…”

Synthesis and Characterization of New Tetraaza Macrocycles Bearing Two or Four N-Methoxyethyl Pendant Arms and Their Copper(II) and/or Nickel(II) Complexes

“…The major product prepared from the reaction of bearing four N-propyl groups, form square-planar copper(II) complexes, in which the metal ion is coordinated by all of the four tertiary nitrogen atoms. 16,17 This can be attributed to the coordination ability of the N-CH2CH2OCH3 groups in L 3 . All efforts to prepare nickel(II) complex of L 3 under various experimental conditions were unsuccessful; the addition of NaClO4 to the reaction mixture produced the white salt L (Fig.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] In general, coordination geometry and chemical properties of such compounds are strongly influenced by the nature and number of the functional groups.…”