Hydrolysis of phosphate esters catalyzed by copper(II)-triamine complexes. The effect of triamine ligands on the reactivity of the copper(II) catalysts

Itoh, Toyofumi; Hisada, Hiroyuki; Usui, Yoshiharu; Fujii, Yuki

doi:10.1016/s0020-1693(98)00222-9

Cited by 68 publications

(75 citation statements)

References 55 publications

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“…Kady et al [31] found that mononuclear Zn II models with N 3 and N 3 O ligands showed k obs values of between 4.5 î 10 À2 and 1.5 î 10 À6 s À1 for diethyl(4-nitrophenyl)phosphate hydrolysis in water. Itoh et al [32] studied the catalytic hydrolysis of 2,4-dinitrophenyl ethylphosphate using mononuclear Cu II complexes with N 3 ligands. These displayed k cat values of between 0.7 î 10 À6 and 1.6 î 10 À3 s…”

Section: Magnetic Propertiesmentioning

confidence: 99%

Pentacoordinate Nickel(II) Complexes Double Bridged by Phosphate Ester or Phosphinate Ligands: Spectroscopic, Structural, Kinetic, and Magnetic Studies

Santana

Garcı́a

Lozano

et al. 2004

Chemistry A European J

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The bis(phosphatediester)-bridged complexes [[Ni([12]aneN(3))(mu-O(2)P(OR)(2))](2)](PF(6))(2) [[12]aneN(3)=Me(3)[12]aneN(3), 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene; R=Me (1), Bu (2), Ph (3), Ph-4-NO(2) (4); [12]aneN(3)=Me(4)[12]aneN(3), 2,4,4,9-tetramethyl-1,5,9-triazacyclododec-1-ene; R=Me (5), Bu (6), Ph (7), Ph-4-NO(2) (8)] were prepared by hydrolysis of the phosphate triester with the hydroxo complex [[Ni([12]aneN(3))(mu-OH)](2)](PF(6))(2) or by acid-base reaction of the dialkyl or diaryl phosphoric acid and the above hydroxo complex. The acid-base reaction was also used to synthesise the phosphinate-bridged complexes [[Ni([12]aneN(3))(mu-O(2)PR(2))](2)](PF(6))(2) [[12]aneN(3)=Me(3)[12]aneN(3), R=Me (9), Ph (10); [12]aneN(3)=Me(4)[12]aneN(3), R=Me (11), Ph (12)]. The molecular structures of complexes 2, 3 and 12 were established by single crystal X-ray diffraction studies. The eight-membered rings defined by the nickel atoms and the bridging ligands show distorted twist-boat, chair and boat-boat conformations in 2, 3 and 12, respectively. The experimental susceptibility data for compounds 2, 3 and 12 were fitted by least-squares methods to the analytical expression given by Ginsberg. The best fit was obtained with values of J=-0.11 cm(-1), D=-9.5 cm(-1) and g=2.20 for 2; J=-0.97 cm(-1), D=-9.3 cm(-1) and g=2.21 for 3; and J=-0.14 cm(-1), D=-11.9 cm(-1) and g=2.195 for 12. The magnetic-exchange pathways must involve the phosphate/phosphinate bridges, because these favour antiferromagnetic interactions. The observation of a higher exchange parameter for compound 3 is a consequence of a favourable disposition of the O-P-O bridges. The kinetics for the hydrolysis of TNP (tris(4-nitrophenyl)phosphate) with the dinuclear nickel(II) hydroxo complex [[Ni(Me(3)[12]aneN(3))(mu-OH)](2)](PF(6))(2) was studied by UV-visible spectroscopy. The proposed mechanism for TNP-promoted hydrolysis can be described as one-substrate/two-product, and can be fitted to a Michaelis-Menten equation.

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Section: Magnetic Propertiesmentioning

confidence: 99%

Pentacoordinate Nickel(II) Complexes Double Bridged by Phosphate Ester or Phosphinate Ligands: Spectroscopic, Structural, Kinetic, and Magnetic Studies

Santana

Garcı́a

Lozano

et al. 2004

Chemistry A European J

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“…Stability constants for the binary Cu(II)-TACH and Cu(II)-dipeptide (ligand B) systems determined under our experimental conditions are available in the Supplementary material (Table S2). In addition to the species detected earlier in the Cu(II)-TACH system [42], [CuAH, CuA and CuAH -1 {or more precisely CuA(OH)}], a monomer-dimer equilibrium of a mixed hydroxo species 2, CuA(OH)M [CuA(OH)] 2 , was also assumed. Formation of the dihydroxo-bridged dinuclear complex was unambiguously proven by the approximately 90% decrease in EPR signal intensity due to antiferromagnetic coupling between the copper(II) centers through the OH -bridges (Fig.…”

Section: Speciation and Epr Study Of The Cu(ii)-tachdipeptide And Cu(mentioning

confidence: 99%

“…We have been studying several copper(II)-triamine complexes that effectively promote the hydrolytic cleavage of DNA [42,43], as well as peptide bonds, and recently briefly reported the crystal structure of the glycylglycine complex of copper(II)-cis,cis-1,3,5-triaminocyclohexane [Cu(II)(TACH)] as a reaction intermediate [44]. In this paper, we discuss the mechanism of the hydrolysis of the dipeptides GlyGly, GlyLeu, LeuGly and GlySer with Cu(II)(TACH), together with the site selectivity of the serine residue [19,20,22] …”

Section: Introductionmentioning

confidence: 99%

Copper(II)-cis,cis-1,3,5-triaminocyclohexane complex-promoted hydrolysis of dipeptides: kinetic, speciation and structural studies

et al. 2002

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The hydrolysis of glycylglycine (GylGly), glycyl-L-leucine (GlyLeu), L-leucylglycine (LeuGly) and glycyl-DL-serine (GlySer) promoted by a copper(II)- cis, cis-1,3,5-triaminocyclohexane complex [Cu(II)TACH] was investigated at 70 degrees C and pH 7-10, using HPLC. The observed pseudo-first-order rate constants (k(obs)) and rate enhancing factors (REF) were as follows: 4.1x10(-3 )h(-1)(REF=23) for GylGly, 1.6x10(-3 )h(-1)(REF=21) for GlyLeu, 5.1x10(-3 )h(-1)(REF=64) for LeuGly and 9.2x10(-2 )h(-1)(REF=47) for GlySer [pH 8.1, dipeptide 2 mM, copper(II) 2 mM and TACH 2 mM]. Based on the pH dependence and dipeptide concentration dependence of the initial rates and speciation of the Cu(II)-TACH-dipeptide system at 25 degrees C and I=0.1, the reactions proceed via the formation of a ternary complex [Cu(TACH)(dipeptide)](+) as an intermediate followed by OH(-)-dependent and OH(-)-independent paths to give amino acid(s). GylGly, GlyLeu and LeuGly preferred the OH(-)-dependent path, while GlySer preferred the OH(-)-independent path. The latter can be explained by the intramolecular attack of the amide carbonyl group coordinated with its oxygen atom by the OH group in the serine residue. The X-ray crystal structure of [Cu(TACH)(GlyGly)]BPh(4).MeOH confirmed that GlyGly coordinates to copper(II) ion with its terminal amino N and amide O atoms. The crystal structures of [Cu(TACH)(Gly)]BPh(4) and [Cu(2)(TACH)(2)(OH)(2)](ClO(4))(2).NaClO(4).H(2)O are also reported.

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“…[28] This reduction is probably due to the effect of both the hydrophobic environment around the coordinated water molecule and weak interactions after complexation in 2, similar to those in carbonic anhydrase or alkaline phosphatase. [18] Values for the pK a2 of water molecules coordinating the same metal ion such as…”

Section: Resultsmentioning

confidence: 98%

“…Zn II with complex L 1 was titrated with various concentrations of b-CD according to a previously described method. [22,23] The…”

Section: Resultsmentioning

confidence: 99%

An Effective Metallohydrolase Model with a Supramolecular Environment: Structures, Properties, and Activities

Zhou

Zhao

et al. 2007

Chemistry A European J

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A supramolecular inclusion complex, [Zn(L1)(H2O)2(beta-CD)](ClO4)2.9.5 H2O (1) was synthesized and characterized structurally and its first-order active species for hydrolysis of esters, [Zn(L1)(H2O)(OH)(beta-CD)](ClO4) (2), was isolated (L1=4-(4'-tert-butylbenzyl)diethylenetriamine; beta-CD=beta-cyclodextrin). The apparent inclusion stability constant of the host and the guest measured in aqueous solution was (5.91+/-0.03)x10(3) for 1. The measured values of the first- and second-order pK(a) values of coordinated water molecules were 8.20+/-0.08 and 10.44+/-0.08, respectively, and were assigned to water molecules occupying the plane and remaining axial positions in a distorted trigonal bipyramid of the [Zn(L1)(H2O)2(beta-CD)]2+ sphere according to the structural analysis of [Zn(L2)(H2O)}2(mu-OH)](ClO4)3 (3) (L2=4-benzyldiethylenetriamine). p-Nitrophenyl acetate (pNA) hydrolysis catalyzed by 1 at pH 7.5-9.1 and 25.0+/-0.1 degrees C exhibited a first-order reaction with various concentrations of pNA and 1, but the pH profile did not indicate saturated kinetic behavior. Second-order rate constants of 0.59 and 24.0 M(-1) s(-1) were calculated for [Zn(L1)(H2O)(OH)(beta-CD)]+ and [Zn(L1)(OH)2(beta-CD)], respectively; the latter exhibited a potent catalytic activity relative to the reported mononuclear and polynuclear Zn(II) species.

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Hydrolysis of phosphate esters catalyzed by copper(II)-triamine complexes. The effect of triamine ligands on the reactivity of the copper(II) catalysts

Cited by 68 publications

References 55 publications

Pentacoordinate Nickel(II) Complexes Double Bridged by Phosphate Ester or Phosphinate Ligands: Spectroscopic, Structural, Kinetic, and Magnetic Studies

Pentacoordinate Nickel(II) Complexes Double Bridged by Phosphate Ester or Phosphinate Ligands: Spectroscopic, Structural, Kinetic, and Magnetic Studies

Copper(II)-cis,cis-1,3,5-triaminocyclohexane complex-promoted hydrolysis of dipeptides: kinetic, speciation and structural studies

An Effective Metallohydrolase Model with a Supramolecular Environment: Structures, Properties, and Activities

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