Kinetics of phosphodiester hydrolysis by lanthanide ions in weakly basic solutions

Gómez-Tagle, Paola; Yatsimirsky, Anatoly K.

doi:10.1039/a806198j

Cited by 24 publications

(23 citation statements)

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“…Rate enhancements in the order of up to 10 6 -10 7 have been reported for Cu(II) [54][55][56][57] and lanthanide(III) complexes [58][59][60][61][62][63][64][65][66]. However, despite the high positive charge of the metal centre, Cp 2 TiCl 2 does not reach the efficiency of Zr(IV) or Ce(IV) that bring about rate enhancements for BNPP cleavage of 10 8 and >10 9 -fold [67][68][69][70].…”

Section: Discussionmentioning

confidence: 97%

Binding and hydrolysis studies of antitumoural titanocene dichloride and Titanocene Y with phosphate diesters

Erxleben

Claffey

Tacke

2010

Journal of Inorganic Biochemistry

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Section: Discussionmentioning

confidence: 97%

Binding and hydrolysis studies of antitumoural titanocene dichloride and Titanocene Y with phosphate diesters

Erxleben

Claffey

Tacke

2010

Journal of Inorganic Biochemistry

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“…pH-rate profile: In Figure 5 is presented the variation of the pseudo-first-order rate constants k obs for BNPP hydrolysis with pH at a definite TEA concentration and a lanthanum(III) concentration, where it can be seen that in the range of near neutrality, the reaction rate grew slowly on increase in pH, while when pH exceeded 8 the rate was increasesd rapidly with pH, which is indicative of formation of reactive hydroxo complexes. 10 Furthermore, no inflection was observed at pH about 11 though further investigation was limited by precipitation at pH above 11, suggesting a larger than 11 of pK a of the bridging hydroxyl in dinuclear species 4 2 2 2 La (OH) L ＋ , where L ＝ TEA. 14 In the case of La(III)-DEA system, a plot of the pseudo-first-order rate constants k obs for BNPP hydrolysis vs. pH gave a Sigmoid curve, as presented in Figure 6, indicating that the catalytically active species in La(III)-DEA system might be also the hydroxo complex.…”

Section: Kinetics Of Bnpp Hydrolysismentioning

confidence: 94%

“…The inorganic phosphate, another possible product of BNPP hydrolysis was determined quantitatively in the reaction mixture by a stan-dard molybdate/hydrazine colorimetric method. 10,13 Analysis of a mixture containing 2.00×10 -2 TEA or DEA , 2.00×10 -3 La(NO 3 ) 3 and 5.00×10 -3 mol•L -1 BNPP after 72 h at 30 ℃ showed the presence of 4.46 ×10 -3 or 4.77×10 -3 H 3 PO 4 and 9.57×10 -3 or 9.68× 10 -3 mol•L -1 p-nitrophenolate. Above experimental results could indicate that the hydrolysis reaction of BNPP might proceed by following way (Scheme 3).…”

Section: Kinetics Of Bnpp Hydrolysismentioning

confidence: 99%

“…The stabilization of reactive hydroxo lanthanide species or in favorable cases, pre-organization of them for an optimum interaction with substrate, by using appropriate ligands, was considered to be one of the key factors in the development of efficient artificial nucleases. Consequently, macrocyclic ligands 5a,5c,5g,5h,5l , tris(hydroxymethyl)aminomethane (Tris) 8b,10 and derivatives of Tris (Bis-Tris 5d,10 and BTP 1,9,10 ) have been successfully employed for the stabilization of the highly charged metal ions, including Ln(III) and Zr(IV), and high catalytic activities of these systems were observed for the hydrolysis of phosphodiesters. We also found that TEA and DEA (Scheme 1) might form esterolytically active complexes with lanthanum(III) in neutral or mild alkaline conditions.…”

Section: Introductionmentioning

confidence: 99%

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Rapid Phosphodiester Hydrolysis Catalyzed by Lanthanum(III)

Kou¹,

Huang

et al. 2005

Chin. J. Chem.

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The catalytic hydrolysis of bis(4-nitrophenyl)phosphate (BNPP) by lanthanum(III) ion in the presence of amino-alcoholic ligands: diethanolamine (DEA) and triethanolamine (TEA), was investigated kinetically at 30 ℃. The results indicated that the dinuclear dihydroxo complexes formed by lanthanum(III) ion with aminoalcoholic ligands might be the catalytically active species which catalyze the hydrolysis of BNPP to different extents and the catalytic mechanism was believed to involve the synergism of double Lewis acid activation of the substrate and an intramolecular nucleophilic attack of a bridging oxo ligand.

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“…The nature of the transition state region not accessible from direct experimental studies can thus be derived from the theoretical calculations. Use of transition metals, 9,12-24 lanthanides, [25][26][27][28][29][30] alkali [31][32][33][34][35][36] and alkaline earth 37,38 metals in phosphodiester hydrolysis have been reported in the literature. The divalent metal ions Ca 2+ , Zn 2+ , Mg 2+ and Mn 2+ are generally incorporated in biological systems.…”

Section: Introductionmentioning

confidence: 99%

Alkali metals (Li, Na, and K) in methyl phosphodiester hydrolysis

Pinjari

Kaptan

Gejji

2009

Phys. Chem. Chem. Phys.

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The phosphodiester linkage central to biological systems has been modeled by methyl phosphodiester (MPDE) in various theoretical and experimental studies. Under physiological conditions, hydrolysis of the phosphodiester is negligible, however this process can be catalyzed in the presence of metal ions. To understand the role of alkali metals in MPDE hydrolysis and, in particular, how it influences the reaction pathway and the associated energetics, density functional calculations employing the 6-31+G(d,p) basis set have been carried out. Different pathways that include the reactant, intermediates and the products have been investigated for MPDE hydrolysis catalyzed by one or two lithium ions, characterized as stationary point geometries on the potential energy surface. The pathways A and B incorporate a single lithium ion bonded to different oxygens of the diester functionality. In pathway C, a six-membered ring was noticed wherein the nucleophile bridges two lithium ions interacting with different oxygens of the phosphoryl group. Furthermore, in the pathway (D) incorporating two lithium ions, one of the lithium ions interacts with the hydroxyl group and another with the methoxy oxygen; both metal ions are coordinated by the same phosphoryl oxygen. In addition to this, yet another pathway (E), where the metal ions are bound to different oxygens of the phosphoryl group, has also been dealt with. The calculations have shown that the A and B pathways lead to a single step reaction. A three-step mechanism including the nucleophilic (hydroxyl) attack, rotation of a methyl group and, finally, departure of the methoxy group has been predicted for the D and E profiles. Both D and E pathways are favored equally (with a marginal difference of 0.3 kJ mol(-1) in their activation energies) in the gas phase and a transition state corresponding to nucleophilic attack with an energy barrier of 32.5 kJ mol(-1) was located when lithium was used. A penta-coordinated phosphorous intermediate on the potential energy surface was characterized along these pathways. MPDE hydrolysis yielded a lower energy barrier for lithium than those for the remaining alkali metal ions. This agrees well with the experimentally observed trend for the hydrolysis rates: Li > Na > K. Self consistent reaction field (SCRF) calculations reveal the lower energy barrier between the reactant and the transition state for the nucleophilic attack in nonpolar solvents. The extent of bond formation (or cleavage) in different stationary point structures along the reaction path as estimated from the electron density at the bond critical point in the molecular electron density topography, has proven useful in distinguishing the associative or dissociative reaction pathways.

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Kinetics of phosphodiester hydrolysis by lanthanide ions in weakly basic solutions

Cited by 24 publications

References 15 publications

Binding and hydrolysis studies of antitumoural titanocene dichloride and Titanocene Y with phosphate diesters

Binding and hydrolysis studies of antitumoural titanocene dichloride and Titanocene Y with phosphate diesters

Rapid Phosphodiester Hydrolysis Catalyzed by Lanthanum(III)

Alkali metals (Li, Na, and K) in methyl phosphodiester hydrolysis

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