Effects of metal ions on the hydrolysis of <i>p</i>‐nitrophenyl caproate by modified poly(ethylenimine)s

Takagishi, Toru; Klotz, Irving M.

doi:10.1002/bip.1979.360181009

Cited by 14 publications

(5 citation statements)

References 15 publications

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“…Although fewer oligomeric polyiodide cations are known, their number is increasing.7 However, only one neutral moiety containing more than a single diodine molecule (bis(((triphenylphosphine sulfide-S)iodine)-/)iodine) appears to have been described. 8 We have now found that the family of neutral molecular compounds, with S as heteroatom in the donor and poly(diiodine) moieties as acceptors, is an extensive one, and we present crystal structure analyses of compounds with formulas • 2, •( 2 The present and earlier structural results suggest that two series of compounds are involved. In the first of these, diiodine chains of varying lengths are attached to sulfur-the examples considered here are • 2 and •( 2)2.…”

mentioning

confidence: 74%

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Crystal structures of polyiodide salts and molecular complexes. 7. Interaction of thiones with molecular diiodine. The crystal structures of dithizone-diiodine, ethylenethiourea-bis(diiodine), bis(ethylenethiourea)-tris(diiodine), bis(dithizone)-heptakis(diiodine), and 1-(1-imidazolin-2-yl)-2-thioxoimidazolidinium triiodide-(ethylenethiourea-diiodine)

Herbstein¹,

Schwotzer²

1984

J. Am. Chem. Soc.

108

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confidence: 74%

“…1978, 7, 697-702). 2(Dithizone)-7(I2) is triclinic (a = 13.312 (8) A, b = 20.637 (7) A, c = 9.746 (6) A, a = 101.8 (1)°, ß = 87.1 (1)°, y = 109. 4 (1)°, Z = 1, space group Pi; RF = 0.086) and has a centrosymmetric, branched twisted chain of iodine molecules held at its ends by strong sulfur-iodine interactions.…”

mentioning

confidence: 99%

Crystal structures of polyiodide salts and molecular complexes. 7. Interaction of thiones with molecular diiodine. The crystal structures of dithizone-diiodine, ethylenethiourea-bis(diiodine), bis(ethylenethiourea)-tris(diiodine), bis(dithizone)-heptakis(diiodine), and 1-(1-imidazolin-2-yl)-2-thioxoimidazolidinium triiodide-(ethylenethiourea-diiodine)

Herbstein¹,

Schwotzer²

1984

J. Am. Chem. Soc.

108

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“…PEI (MW 50 000−60 000, purchased from Aldrich) was purified by dialysis (cutoff MW 12 000). Laurylation of PEI was carried out with Lau bromide according to the procedure reported in the literature to obtain Lau 1 PEI, Lau 6 PEI, Lau 12 PEI, and Lau 18 PEI. The contents of Lau groups in Lau 1 PEI, Lau 6 PEI, Lau 12 PEI, and Lau 18 PEI were 1.2, 5.9, 12, and 18 residue mol %, respectively, as measured by NMR spectrometry.…”

Section: Methodsmentioning

confidence: 99%

Catalytic Activity of Ni(II)−Terpyridine Complex in Phosphodiester Transesterification Remarkably Enhanced by Self-Assembly of Terpyridines on Poly(ethylenimine)

Suh

Hong

1998

J. Am. Chem. Soc.

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To enhance the catalytic activity of metal-terpyridyl complexes toward transesterification of an RNA model [(2-hydroxypropyl)-p-nitrophenyl phosphate, HPNPP], the conformation of terpyridyl moieties assembled on poly(ethylenimine) (PEI) is optimized by attaching the Ni(II) complex of a terpyridyl derivative (Ni II TP) and lauryl (Lau) group to PEI in random combinations. The catalytic activity per Ni(II) center for transesterification of HPNPP varies by up to several thousand times depending on pH as the content of Ni II TP or Lau is changed. The best catalyst obtained is [Ni II TP] 5 Lau 12 PEI, in which the contents of Ni II TP and Lau are 5 and 12 residue mol %, respectively. The catalytic activity of [Ni II TP] 5 Lau 12 PEI expressed in terms of k cat is much higher than those of previously reported binuclear metal complexes whose structures were designed through deliberate planning. In the PEI derivatives containing Ni II TP and Lau, several Ni II TP groups can be positioned in proximity in the hydrophobic clusters formed on the polymer. When the Ni II TP groups take productive positions, the two phosphoryl-oxygen bonds and the hydroxyl group of HPNPP can be effectively activated. Thus, artificial active sites comprising multiple catalytic groups are obtained by self-assembly of the catalytic groups. Moreover, cooperative action among the catalytic groups is optimized through combinatorial approach.

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“…The rate of p-nitrophenyl caproate hydrolysis by modified PEI, containing imidazole groups in the presence of metal ions, increased in the sequence Mn2+, Ni2+, Zn2+, Co2+, Cu2+ [92]. Among the selected metals, a copper complex was shown to be most effective, the maximum rate being achieved at a [imidazole]/[copper] ratio of 2.75.…”

Section: Menten Equation [64]mentioning

confidence: 99%

“…Polymers, with [q] = 0.30-0.56 dl/g, containing methyl sulfonyl groups have been synthesized by copolymerization of methyl-4-vinylphenyl sulfoxide with styrene [92]. These copolymers are soluble in toluene but are insoluble in water.…”

Section: Interfacial Catalysismentioning

confidence: 99%

Catalytic Properties of Polymers in Solutions

Bekturov¹,

Kudaibergenov²

1997

Catalysis by Polymers

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Polymers are increasingly being used as active components in synthesis and catalysis [I -121. Three basic directions of polymer application are cited as follows:( 1 ) use of polymers as reagents; (2) application of functional groups of polymers as catalysts; and (3) use of polymers as supports. Catalysis by functional groups of macromolecules has attracted scientists' attention owing to the rapid development of enzyme catalysis. High catalytic activity of enzymes is attributed to the broad variety of their particular functional groups which enables their involvement in multiple interactions. The main limitation for using polymers in enzyme catalysis is their lack of a diverse functional group. Consequently, complex enzyme functions cannot yet be realized by synthetic analogues. Nevertheless, the molecular nature of proteins has prompted many scientists to focus on catalytic systems based on synthetic polymers as simple model proteins, metalloenzymes and ferments.This chapter presents various examples of enzyme catalysis by polymers including ester hydrolysis, decomposition of hydrogen peroxide, oxidation of disubstituted phenols and hydroquinone, interfacial catalysis and other types of reaction. Because metal ions (Fe, Zn, Cu. Mn, Co, erc.) are often involved as coferments during enzyme catalysis, some examples illustrating their catalytic action are also given. The catalytic activity of polymeric coordination compounds is shown to depend on the strength of the ligand-metal bond.

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Effects of metal ions on the hydrolysis of p‐nitrophenyl caproate by modified poly(ethylenimine)s

Cited by 14 publications

References 15 publications

Catalytic Activity of Ni(II)−Terpyridine Complex in Phosphodiester Transesterification Remarkably Enhanced by Self-Assembly of Terpyridines on Poly(ethylenimine)

Catalytic Properties of Polymers in Solutions

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