Rapid hydrolysis of phosphate monoesters by zirconium(IV) complexes in neutral solution

Coleman, Fergal; Erxleben, Andrea

doi:10.1016/j.poly.2012.09.015

Cited by 6 publications

(3 citation statements)

References 28 publications

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“…The hydrolysis mechanisms of phosphate diesters catalyzed by metal complexes have been extensively studied. In contrast, a very limited number of experimental and theoretical efforts have been made to study the hydrolytic cleavage of phosphate monoesters. ,− In uncatalyzed hydrolysis reactions of phosphor-monoesters, the monoester dianions are acknowledged to undergo a concerted process involving a loose transition state, while the hydrolysis of monoester monoanions is thought to be concerted or to undergo a preassociative mechanism involving a discrete metaphosphate intermediate. , In particular, the phosphate monoester dianions are less reactive than the monoanions, and the catalytic advantage of the monoester monoanions is that for the leaving group protonation a proton transfers from the phosphoryl oxygen atom to the leaving group in the P–O bond fission reaction step. However, there are still some uncertainties in the metal-complex-catalyzed hydrolysis mechanisms and the corresponding binding modes of the catalyst–substrate complexes, especially for the phosphate monoester monoanions.…”

Section: Introductionmentioning

confidence: 99%

Mechanismic Investigation on the Cleavage of Phosphate Monoester Catalyzed by Unsymmetrical Macrocyclic Dinuclear Complexes: The Selection of Metal Centers and the Intrinsic Flexibility of the Ligand

et al. 2014

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The hydrolysis mechanisms of phosphor-monoester monoanions NPP(-) (p-nitrophenyl phosphate) catalyzed by unsymmetrical bivalent dinuclear complexes are explored using DFT calculations in this report. Four basic catalyst-substrate binding modes are proposed, and two optional compartments for the location of the nucleophile-coordinated metal center are also considered. Five plausible mechanisms are examined in this computational study. Mechanisms 1, 2, and 3 employ an unsymmetrical dizinc complex. All three mechanisms are based on concerted SN2 addition-substitution pathways. Mechanism 1, which involves more electronegative oxygen atoms attached to the imine nitrogen atoms in the nucleophile-coordinated compartment, was found to be more competitive compared to the other two mechanisms. Mechanisms 4 and 5 are based on consideration of the substitution of the bivalent metal centers and the intrinsic flexibility of the ligand. Both mechanisms 4 and 5 are based on stepwise SN2-type reactions. Magnesium ions with hard base properties and more available coordination sites were found to be good candidates as a substitute in the M(II) dinuclear phosphatases. The reaction energy barriers for the more distorted complexes are lower than those of the less distorted complexes. The proper intermediate distance and a functional second coordination sphere lead to significant catalytic power in the reactions studied. More importantly, the mechanistic differences between the concerted and the stepwise pathways suggest that a better nucleophile with more available coordination sites (from either the metal centers or a functional second coordination sphere) favors concerted mechanisms for the reactions of interest. The results reported in the paper are consistent with and provide a reasonable interpretation for experimental observations in the literature. More importantly, our present results provide some practical suggestions for the selection of the metal centers and how to approach the design of a catalyst.

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Section: Introductionmentioning

confidence: 99%

Mechanismic Investigation on the Cleavage of Phosphate Monoester Catalyzed by Unsymmetrical Macrocyclic Dinuclear Complexes: The Selection of Metal Centers and the Intrinsic Flexibility of the Ligand

et al. 2014

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“…In order to deepen our understanding, the variation of hydrolysis rate by a function of substrate concentration were investigated [31] . The rate of hydrolysis can be expressed as the concentration of reactants decreases or the concentration of production increases with the time increasing as: V=−d[s]/dt=d[NP]/dt, on the basis of Lambert‐Beer's law, A=ϵbc (b=1 cm), V=dA/ϵdt was extracted, where the molar extinction coefficient of 4‐nitrophenol has been measured and equal to 15150 mol −1 L cm −1 at 406 nm.…”

Section: Kinetic Investigation On Phosphate Ester Hydrolysismentioning

confidence: 99%

Macrocyclic Complexes Derived from 2,6‐Diformyl‐4‐X‐phenol: Substituent Effects and Phosphate Hydrolysis Activity

Wang

Mao

Wu³

et al. 2021

ChemistrySelect

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Two 20‐membered macrocyclic complexes, [Cu2L1(ClO4)2] (1) and [Ni2L2(ClO4)2(H2O)2][Cu2L2(H2O)2](ClO4)2 (2) (where H2L1 and H2L2 are the condensation products of ɑ, ω‐amine with 3,3′‐((propane‐1,3‐diylbis(azanylylidene)) bis(methanylylidene))bis(5‐X‐2‐hydroxybenzaldehyde)), have been synthesized and characterized by X‐ray diffractions single crystal structure analysis. The results indicated that the structures of two complexes are symmetrical. In complex 1, the geometry around each copper(II) center is a slightly distorted square pyramidal with structural index parameter τ=0.062 for Cu1 and 0.067 for Cu2, the distance between Cu1 and Cu2 is 3.1075 Å. Complex 2 contains two similar macrocyclic units (A and B), the metal‐metal distances in A and B are 3.0760 and 3.0922 Å, respectively. The interaction between the complexes and calf thymus (CT‐DNA) were investigated by spectroscopic method. The phosphate hydrolysis activities of the complexes were examined using 4‐nitrophenyl phosphate disodium salt hexahydrate (pNPP) as the substrate. The corresponding catalytic rate constant (kcat) at pH 7.2 are 2.14×10−5 and 2.85×10−5 s−1, respectively, 104 times faster than the spontaneous hydrolysis of phosphate monoester.

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“…As for the cyclo-mono-μ-imidotriphosphate and cyclo-diμ-imidotriphosphate anions which include bridging of oxygen atoms in the cyclic molecular skeleton, the P-O bond is easily cleaved by hydrolysis which is caused by the nucleophilic attack from water molecules. [45][46][47][48][49][50][51] Consequently, the cyclo-diμ-imidotriphosphate sodium salt, Na 3 cP 3 O 7 (NH) 2 , in which one of the bridging nitrogen atoms in cyclo-tri-μ-imidotriphosphate sodium salt, Na 3 cP 3 O 6 (NH) 3 , was replaced by an oxygen atom, is applied to a starting material for the synthesis of diimidotriphosphate sodium salt, Na 5 P 3 O 8 (NH) 2 , which has a short chain molecular structure. 37,38,52 Similarly, Na 4 cP 4 O 9 (NH) 3 is expected to be used as a starting material for the synthesis of Na 6 P 4 O 10 (NH) 3 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, protonation equilibrium and peculiar thermal decomposition behavior of cyclo-tri-μ-imidotetraphosphate

et al. 2014

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The synthesis and isolation of the sodium salt of cyclo-tri-μ-imidotetraphosphate, i.e. Na4cP4O9(NH)3·H2O, were achieved by the hydrolysis of Na4cP4O8(NH)4·2H2O under very weak acidic conditions, i.e. using 0.2 mol L(-1) propionic acid and the pH-controlled recrystallization procedure. The purity of Na4cP4O9(NH)3·H2O was improved from 2% to 95% by the pH-controlled recrystallization only two times. The first protonation constants of a series of cyclo-μ-imidotetraphosphate anions, i.e. cP4O(12-n)(NH)n(4-) (n = 0, 2, 3, 4), were determined by potentiometric titration and (31)P NMR chemical shift measurements in aqueous solution. Regardless of the paucity of the purity of trans-cP4O10(NH)2(4-) anions, the protonation processes of all anions may be evaluated accurately without any previous purification, because the NMR signals corresponding to cP4O(12-n)(NH)n(4-) (n = 0, 2, 3, 4) anions are well resolved. The logarithmic first protonation constants increase with a "linear" increase in the number of imino groups which constitute the ligand molecules. Macroscopic protonation reactions could be divided into three microscopic protonation processes for -O-PO2-O-, -O-PO2-NH-, and -NH-PO2-NH- groups. The basicity of the -NH-PO2-NH- group is especially high, because the delocalization of H(+) ions by lactam-lactim tautomerism on the whole ring molecule of cP3O6(NH)3 and cP4O8(NH)4 enhances the protonation of these ligands. In addition, also the concurrent change observed in the (31)P NMR chemical shift values of the phosphorus nuclei in the -O-PO2-NH- and -NH-PO2-NH- groups of cP4O9(NH)3(4-) anions suggested the effect of the lactam-lactim tautomerism. The intrinsic (31)P NMR chemical shifts for the central phosphorus nuclei for -O-PO2-O-, -O-PO2-NH-, and -NH-PO2-NH- groups show a good proportional relationship with the number of nitrogen atoms bonded to the central phosphorus atoms. Two types of imino groups with mutually dissimilar chemical environments which are present in the Na4cP4O9(NH)3 molecule, that is -O-PO2-NH-PO2-NH- and -NH-PO2-NH-PO2-NH-, brought about a two-stage pyrolytic elimination of imino groups from the initial stage of combustion over a wide temperature range.

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Rapid hydrolysis of phosphate monoesters by zirconium(IV) complexes in neutral solution

Cited by 6 publications

References 28 publications

Mechanismic Investigation on the Cleavage of Phosphate Monoester Catalyzed by Unsymmetrical Macrocyclic Dinuclear Complexes: The Selection of Metal Centers and the Intrinsic Flexibility of the Ligand

Mechanismic Investigation on the Cleavage of Phosphate Monoester Catalyzed by Unsymmetrical Macrocyclic Dinuclear Complexes: The Selection of Metal Centers and the Intrinsic Flexibility of the Ligand

Macrocyclic Complexes Derived from 2,6‐Diformyl‐4‐X‐phenol: Substituent Effects and Phosphate Hydrolysis Activity

Synthesis, protonation equilibrium and peculiar thermal decomposition behavior of cyclo-tri-μ-imidotetraphosphate

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