Given the practical advantages of (68)Ga isotope in positron emission tomography applications, gallium complexes are gaining increasing importance biomedical imaging. However, strong tendency Ga(3+) to hydrolyze and slow formation very high stability macrocyclic altogether render coordination chemistry difficult explain why kinetic data on rather scarce. Here we report solution solid-state studies formed with ligand 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, (DOTA)(4-), its...

For application in positron emission tomography (PET), PrP9, a N,N',N''-trisubstituted triazacyclononane with methyl(2-carboxyethyl)phosphinic acid pendant arms, was developed as (68)Ga(3+) complexing agent. The synthesis is short and inexpensive. Ga(III) Fe(III) complexes of PrP9 were characterized by single-crystal X-ray diffraction. Stepwise protonation constants thermodynamic stabilities metal determined potentiometry. complex possesses high stability (log K([GaL])=26.24) degree kinetic...

A new macrocyclic DOTA-like ligand (BPAMD) for bone imaging and therapy containing a monoamide bis(phosphonic acid) bone-seeking group was designed synthesized. Its lanthanide(III) complexes were prepared characterized by 1H 31P NMR spectroscopy. The Gd(III)−BPAMD complex investigated in detail 17O relaxometric studies to inspect parameters relevant its potential application as an MRI contrast agent. Sorption experiments conducted with Gd(III) Tb(III) using hydroxyapatite (HA) model of...

Three phosphinic acid 1,4,7-triazacyclononane (TACN) derivatives bearing methylphosphinic (TRAP-H), methyl(phenyl)phosphinic (TRAP-Ph), or methyl(hydroxymethyl)phosphinic (TRAP-OH) pendant arms were investigated as members of a new family efficient Ga3+ chelators, TRAP ligands (triazacyclononane acids). Stepwise protonation constants and stability their complexes with Ga3+, selected divalent metal, Ln3+ ions determined by potentiometry. For comparison, equilibrium data for the metal ion–NOTA...

The kinetics of transmetallation [Mn(nota)]− and [Mn(dota)]2− was investigated in the presence Zn2+ (5–50-fold excess) at variable pH (3.5–5.6) by 1H relaxometry. dissociation is much faster for than under both experimental physiologically relevant conditions (t½ = 74 h 1037 [Mn(dota)]2−, respectively, 7.4, c(Zn2+) 10−5 M, 25 °C). complexes proceeds mainly via spontaneous ([Mn(nota)]−k0 (2.6 ± 0.5) × 10−6s−1; [Mn(dota)]2−k0 (1.8 0.6) 10−7s−1) proton-assisted pathways ([Mn(nota)]−k1 (7.8 0.1)...

Abstract Diethylenetriamine‐ N,N,N′,N′′,N′′ ‐pentaacetic acid (DTPA) and 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic (DOTA) scandium(III) complexes were investigated in the solution solid state. Three 45 Sc NMR spectroscopic references suitable for aqueous solutions suggested: 0.1 M Sc(ClO 4 ) 3 1 aq. HClO ( δ =0.0 ppm), ScCl HCl =1.75 ppm) 0.01 [Sc(ox) ] 5− (ox 2− =oxalato) K 2 C O =8.31 ppm). In solution, [Sc(dtpa)] complex =83 ppm, ▵ ν =770 Hz) has a rather symmetric ligand field...

Ligands with geminal bis(phosphonic acid) appended to 1,4,7‐triazacyclonone‐1,4‐diacetic acid fragment through acetamide (NOTAM BP ) or methylenephosphinate (NO2AP spacers designed for 68 Ga were prepared. III complexation is much faster ligand spacer than that one, in both chemical (high reactant concentrations) and radiolabeling studies no‐carrier‐added Ga. For ligands, formation of complex was slower NOTA owing the strong out‐of‐cage binding bis(phosphonate) group. Radiolabeling efficient...

Lanthanide complexes of DOTA derivatives 2a (BPAMD) and 2b (BPAPD), having a monoamide pendant arm with bis(phosphonate) moiety, were comparatively tested for application in MRI, radiotherapy, bone pain palliation. 1H, 31P, 17O NMR spectroscopy show that they are nine-coordinated, one water molecule the first coordination sphere Ln(III) ion. The moieties not coordinated to lanthanide predominantly mono- diprotonated at physiological pH. parameters governing longitudinal relaxivities Gd...

In an effort toward the visualization of β-amyloid plaques by in vivo imaging techniques, we have conjugated optimized derivative Pittsburgh compound B (PiB), a well-established marker Aβ plaques, to DO3A-monoamide that is capable forming stable, noncharged complexes with different trivalent metal ions including Gd(3+) for MRI and (111)In(3+) SPECT applications. Proton relaxivity measurements evidenced binding Gd(DO3A-PiB) amyloid peptide Aβ1-40 human serum albumin, resulting two- four-fold...

H3nota derivatives are among the most studied macrocyclic ligands and widely used for metal ion binding in biology medicine. Despite more than 40 years of chemical research on H3nota, comprehensive study its solution chemistry has been overlooked. Thus, coordination behavior with several divalent ions was detail respect to application as a chelator copper radioisotopes medical imaging therapy. In solid-state structure free ligand zwitterionic form, one proton is bound cavity through strong...

Metastatic bone lesion is a common syndrome of many cancer diseases in an advanced state. The major symptom severe pain, spinal cord compression, and pathological fracture, associated with obvious morbidity. Common treatments including systemic application bisphosphonate drugs aim on pain reduction improving the quality life patient. Particularly, patients multiple metastatic lesions benefit from bone-targeting therapeutic radiopharmaceuticals. Agents utilizing beta-emitting radionuclides...

The Cu II complex of 1,8-bis(2-hydroxybenzyl)-cyclam forms an unexpected variety isomers differing in the mutual orientation substituents on cyclam nitrogen atoms, protonation phenolate pendant, and ligand denticity.

Abstract Five geminal bis(phosphonates) containing an amino group in the α, γ or δ position of carbon chain have been synthesised and their acid–base complexation properties with Cu 2+ , Zn Ca Mg Na + ions studied by potentiometry. Determination stability constants complexes divalent metal is complicated formation precipitates. The results these studies show a negligible effect hydroxo α on ligands. presence position, however, decreases basicity, which lower ability bis(phosphonates)....

Complexes of 4,10-bis(phosphonomethyl)-1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (trans-H(6)do2a2p, H(6)L) with transition metal and lanthanide(III) ions were investigated. The stability constant values the divalent trivalent metal-ion complexes are between corresponding H(4)dota H(8)dotp complexes, as a consequence ligand basicity. solid-state structures nine determined by X-ray diffraction. All present twisted-square-antiprismatic isomers their can be divided into two series. first...

The complexation ability of DOTA analogs bearing one methylenephosphonic (DO3AP) or methylenephosphinic (DO3AP(PrA) and DO3AP(ABn)) acid pendant arm toward scandium was evaluated. Stability constants their scandium(iii) complexes were determined by potentiometry combined with (45)Sc NMR spectroscopy. stability the monophosphinate analogues are somewhat lower than that Sc-DOTA complex. phosphorus moiety interacts trivalent even in very acidic solutions forming out-of-cage complexes; strong...

A new phosphinic-acid DOTA-like ligand, DO3APBP, containing a geminal bis(phosphonic acid) moiety as highly effective bone-seeking group, was synthesized in high yield. Its crystal structure determined by X-ray analysis. Complexation with lanthanide(III) ions occurs under mild conditions (pH = 8–9, 25 °C, 2–3 h). 1H, 31P, and 17O NMR spectroscopy show that DO3APBP forms nine-coordinated complexes one water molecule the first coordination sphere except for Ln Er–Lu, which have addition...

Multimodal imaging-therapeutic nanoprobe TiO(2)@RhdGd was prepared and successfully used for in vitro vivo cell tracking as well killing of cancer cells vitro. TiO(2) nanoparticles were a core phosphonic acid modified functionalities, responsible contrast MRI optical imaging. The probe shows high (1)H relaxivity density values. Presence fluorescent dye allows visualization by means fluorescence microscopy. applicability the studied, using mesenchymal stem cells, HeLa T-lymphocytes. did not...

Cyclam derivatives bearing one geminal bis(phosphinic acid), -CH2PO2HCH2PO2H2 (H2L(1)), or phosphinic-phosphonic acid, -CH2PO2HCH2PO3H2 (H3L(2)), pendant arm were synthesized and studied as potential copper(II) chelators for nuclear medical applications. The ligands showed good selectivity over zinc(II) nickel(II) ions (log KCuL = 25.8 27.7 H2L(1) H3L(2), respectively). Kinetic study revealed an unusual three-step complex formation mechanism. initial equilibrium step leads to out-of-cage...

We propose a new approach for the versatile sensitization of luminescent lanthanide cations. A hydrophobic chromophore is incorporated into micellar assembly formed by amphiphilic chelate. The sensitizer to energy transfer occurs between two moieties without covalent linkage.