Aminoalkylbis(phosphonates): Their Complexation Properties in Solution and in the Solid State

Kubíček, Vojtěch; Kotek, Jan; Hermann, Petr; Lukeš, Ivan

doi:10.1002/ejic.200600615

Cited by 67 publications

(64 citation statements)

References 27 publications

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“…During complex formation, the proton in [Sc(HL)] species should be bound to a ring nitrogen atom similarly as suggested for lanthanide(III) or gallium-(III) complexes under analogous conditions. [41,43] Stability constant values, log K ScL , are higher than those determined before for the same systems and this is probably caused by the utilization of different methods. The previously used methods could underestimate stability constant values due to using low overall concentration of scandium(III) or complete formation of the complex under the utilized conditions.…”

Section: Stability Constants Of the Scandium(iii) Complexescontrasting

confidence: 46%

“…[18,20] Stability constants of scandium(III) complexes with these ligands are much higher (4-6 orders of magnitude) than those of lanthanide(III) or gallium(III) complexes. [33,42,43] It is expected, as interaction of such a small hard metal ion with highly charged polycarboxylate ligands is stronger (in comparison with Ln 3 + -complexes, eight donor atoms) and the Sc 3 + ion employs all available donor atoms of the ligands (in comparison with Ga 3 + complexes with six donor atoms). Inclusion of the protonated species into chemical model is meaningful, taking into account mechanism of the complex formation in which the "out-ofcage" complex with protonated nitrogen atoms is formed first followed by a rearrangement with metal ion transfer into […”

Section: Stability Constants Of the Scandium(iii) Complexesmentioning

confidence: 97%

“…To check the complex protonation and to help interpretation of the kinetic data, a titration (pH range 1.4-6) of the preformed complex was carried out to determine its log K a analogously to the titration of the preformed [Ga(dota)] À complex. [43] No protonation constant could be fitted from the data.…”

Section: Stability Constants Of the Scandium(iii) Complexesmentioning

confidence: 99%

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Thermodynamic and Kinetic Study of Scandium(III) Complexes of DTPA and DOTA: A Step Toward Scandium Radiopharmaceuticals

Pniok

Kubíček

Havlíčková

et al. 2014

Chemistry A European J

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Diethylenetriamine-N,N,N',N'',N''-pentaacetic acid (DTPA) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) scandium(III) complexes were investigated in the solution and solid state. Three (45)Sc NMR spectroscopic references suitable for aqueous solutions were suggested: 0.1 M Sc(ClO4)3 in 1 M aq. HClO4 (δSc =0.0 ppm), 0.1 M ScCl3 in 1 M aq. HCl (δSc =1.75 ppm) and 0.01 M [Sc(ox)4](5-) (ox(2-) = oxalato) in 1 M aq. K2C2O4 (δSc =8.31 ppm). In solution, [Sc(dtpa)](2-) complex (δSc = 83 ppm, Δν = 770 Hz) has a rather symmetric ligand field unlike highly unsymmetrical donor atom arrangement in [Sc(dota)](-) anion (δSc = 100 ppm, Δν = 4300 Hz). The solid-state structure of K8[Sc2(ox)7]⋅13 H2O contains two [Sc(ox)3](3-) units bridged by twice "side-on" coordinated oxalate anion with Sc(3+) ion in a dodecahedral O8 arrangement. Structures of [Sc(dtpa)](2-) and [Sc(dota)](-) in [(Hguanidine)]2[Sc(dtpa)]⋅3 H2O and K[Sc(dota)][H6 dota]Cl2⋅4 H2O, respectively, are analogous to those of trivalent lanthanide complexes with the same ligands. The [Sc(dota)](-) unit exhibits twisted square-antiprismatic arrangement without an axial ligand (TSA' isomer) and [Sc(dota)](-) and (H6 dota)(2+) units are bridged by a K(+) cation. A surprisingly high value of the last DOTA dissociation constant (pKa =12.9) was determined by potentiometry and confirmed by using NMR spectroscopy. Stability constants of scandium(III) complexes (log KScL 27.43 and 30.79 for DTPA and DOTA, respectively) were determined from potentiometric and (45)Sc NMR spectroscopic data. Both complexes are fully formed even below pH 2. Complexation of DOTA with the Sc(3+) ion is much faster than with trivalent lanthanides. Proton-assisted decomplexation of the [Sc(dota)](-) complex (τ1/2 =45 h; 1 M aq. HCl, 25 °C) is much slower than that for [Ln(dota)](-) complexes. Therefore, DOTA and its derivatives seem to be very suitable ligands for scandium radioisotopes.

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Section: Stability Constants Of the Scandium(iii) Complexescontrasting

confidence: 46%

Section: Stability Constants Of the Scandium(iii) Complexesmentioning

confidence: 97%

Section: Stability Constants Of the Scandium(iii) Complexesmentioning

confidence: 99%

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Thermodynamic and Kinetic Study of Scandium(III) Complexes of DTPA and DOTA: A Step Toward Scandium Radiopharmaceuticals

Pniok

Kubíček

Havlíčková

et al. 2014

Chemistry A European J

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“…It is known that dota-like macrocycles, and especially phosphonic acids, are able to interact with alkali metal cations, [24,36,40,42,43] which lowers the protonation constants values, and so the use of the non-complexing NMe 4 + cation in the present work is more appropriate for the title ligand.…”

Section: Resultsmentioning

confidence: 98%

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

Campello¹,

Lacerda²,

Pereira

et al. 2010

Chemistry A European J

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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 of the divalent and trivalent metal-ion complexes are between the corresponding values of H(4)dota and H(8)dotp complexes, as a consequence of the ligand basicity. The solid-state structures of the ligand and of nine lanthanide(III) complexes were determined by X-ray diffraction. All the complexes are present as twisted-square-antiprismatic isomers and their structures can be divided into two series. The first one involves nona-coordinated complexes of the large lanthanide(III) ions (Ce, Nd, Sm) with a coordinated water molecule. In the series of Sm, Eu, Tb, Dy, Er, Yb, the complexes are octa-coordinated only by the ligand donor atoms and their coordination cages are more irregular. The formation kinetics and the acid-assisted dissociation of several Ln(III)-H(6)L complexes were investigated at different temperatures and compared with analogous data for complexes of other dota-like ligands. The [Ce(L)(H(2)O)](3-) complex is the most kinetically inert among complexes of the investigated lanthanide(III) ions (Ce, Eu, Gd, Yb). Among mixed phosphonate-acetate dota analogues, kinetic inertness of the cerium(III) complexes is increased with a higher number of phosphonate arms in the ligand, whereas the opposite is true for europium(III) complexes. According to the (1)H NMR spectroscopic pseudo-contact shifts for the Ce-Eu and Tb-Yb series, the solution structures of the complexes reflect the structures of the [Ce(HL)(H(2)O)](2-) and [Yb(HL)](2-) anions, respectively, found in the solid state. However, these solution NMR spectroscopic studies showed that there is no unambiguous relation between (31)P/(1)H lanthanide-induced shift (LIS) values and coordination of water in the complexes; the values rather express a relative position of the central ions between the N(4) and O(4) planes.

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“…[23] POM precursor and the alendronic acid H 2 O 3 PC(OH)(C 3 H 6 NH 2 )PO 3 H 2 (H 5 Ale) [24] were synthesized according to reported procedures. All other chemicals were used as purchased without purification.…”

Section: Methodsmentioning

confidence: 99%

Covalent Attachment of Thiophene Groups to Polyoxomolybdates or Polyoxotungstates for the Formation of Hybrid Films

et al. 2015

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A novel bisphosphonate ligand bearing a thiophene group (AleThio) was synthesized and its covalent grafting to polyoxometalates (POMs) investigated. The hybrid polyoxomolybdate [(Mo3O8)4(O3PC(O)(C3H6NH2CH2C4H3S)PO3)4]8– [Mo12(AleThio)4] was synthesized in water by the reaction of Na2MoO4 with AleThio. It is built of four {MoVI3O8} units connected by phosphonate groups around a central Na+ ion. The reaction of the trivacant [PW9O34]9– units with CoII or NiII ions in the presence of AleThio led to the sandwich‐type anions [(PW9O34)2(OH)2(H2O)4M7(O3PC(O)(C3H6NH2CH2C4H3S)PO3)2]14– [M = Ni, Co; M7(AleThio)2]. Salts soluble in organic solvent were prepared by cation‐exchange with bis(triphenylphosphine)iminium ions. 31P NMR spectroscopy showed that Mo12(AleThio)4 is stable in acidic medium (pH ≤ 4) while the M7(AleThio)2 POMs are stable in alkaline medium (6 ≤ pH ≤ 13). Their cyclovoltammograms were recorded in solution. Attempts to surface immobilize the POMs through homo‐polymerization were unsuccessful but co‐polymerization employing 3‐methylthiophene led to polymeric films with covalently attached POMs.

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Aminoalkylbis(phosphonates): Their Complexation Properties in Solution and in the Solid State

Cited by 67 publications

References 27 publications

Thermodynamic and Kinetic Study of Scandium(III) Complexes of DTPA and DOTA: A Step Toward Scandium Radiopharmaceuticals

Thermodynamic and Kinetic Study of Scandium(III) Complexes of DTPA and DOTA: A Step Toward Scandium Radiopharmaceuticals

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

Covalent Attachment of Thiophene Groups to Polyoxomolybdates or Polyoxotungstates for the Formation of Hybrid Films

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Aminoalkylbis(phosphonates): Their Complexation Properties in Solution and in the Solid State

Cited by 67 publications

References 27 publications

Thermodynamic and Kinetic Study of Scandium(III) Complexes of DTPA and DOTA: A Step Toward Scandium Radiopharmaceuticals

Thermodynamic and Kinetic Study of Scandium(III) Complexes of DTPA and DOTA: A Step Toward Scandium Radiopharmaceuticals

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

Covalent Attachment of Thiophene Groups to Polyoxomolybdates or Poly­oxotungstates for the Formation of Hybrid Films

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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

Covalent Attachment of Thiophene Groups to Polyoxomolybdates or Polyoxotungstates for the Formation of Hybrid Films