- Enhanced hydrolytic activity of Cu(II) and Zn(II) complexes in highly cross-linked polymers
-
The chelate ligand tris[(1-vinylimidazol-2-yl)methyl]amine (5) was synthesized in five steps from commercially available starting materials. Upon reaction with ZnCl2 or CuCl2 in the presence of NH 4PF6, the complexes [Zn(5)Cl]PF6 (6) and [Cu(5)Cl]PF6 (7) were obtained. The structure of both complexes was determined by single-crystal X-ray crystallography. Immobilization of 6 and 7 was achieved by co-polymerization with ethylene glycol dimethacrylate. The supported complexes P6-Zn and P7-Cu were found to be efficient catalysts for the hydrolysis of bis(p-nitrophenyl)phosphate (BNPP) at 50 °C. At pH 9.5, the heterogeneous catalyst P7-Cu was 56 times more active than the homogeneous catalyst 7. Partitioning effects, which increase the local concentration of BNPP in the polymer, are shown to contribute to the enhanced activity of the immobilized catalyst. The Royal Society of Chemistry 2006.
- Schiller, Alexander,Scopelliti, Rosario,Severin, Kay
-
-
Read Online
- P-nitrophenyl phosphate disodium and preparation method thereof
-
The invention provides p-nitrophenyl phosphate disodium and a preparation method thereof. The preparation method comprises the following steps: 1, enabling p-nitrophenol to react with dialkyl chloridephosphate in the presence of an alkali so as to obtain O,O-dialkyl p-nitrophenyl phosphate; 2, performing an alkyl ester desorption reaction on the O,O-dialkyl p-nitrophenyl phosphate and a compoundwith trimethylsilyl groups so as to obtain O,O-di(trimethylsilyl) p-nitrophenyl phosphate; 3, performing a hydrolysis reaction on the O,O-di(trimethylsilyl) p-nitrophenyl phosphate so as to obtain p-nitrophenyl phosphate; and 4, enabling the p-nitrophenyl phosphate to react with sodium hydroxide, so as to obtain the p-nitrophenyl phosphate disodium. According to the preparation method provided bythe invention, the intermediate product obtained in the step 1 can be purified through vacuum distillation, and byproducts which are hard to remove are not generated in later operation of ether hydrolysis or pH value adjustment, so that the purification difficulty of the product is greatly reduced; and due to selection of the compound with the trimethylsilyl groups, hydrolysis can be implemented thoroughly, and in addition, the system can be clean.
- -
-
Paragraph 0062; 0080-0083; 0084; 0091; 0092
(2020/01/12)
-
- Solution speciation of the dinuclear ZrIV-substituted keggin polyoxometalate [{α-PW11O39Zr(μ-OH)(H2O)}2]8- and Its reactivity towards DNA-model phosphodiester hydrolysis
-
The solution speciation of the ZrIV-substituted Keggin polyoxometalate (Et2NH2)8[{α-PW11O39Zr(μ-OH)(H2O)}2]·7H2O (ZrK 2:2) was fully determined under differ
- Luong, Thi Kim Nga,Absillis, Gregory,Shestakova, Pavletta,Parac-Vogt, Tatjana N.
-
supporting information
p. 5276 - 5284
(2015/04/22)
-
- The advantage of covalent capture in the combinatorial screening of a dynamic library for the detection of weak interactions
-
In this paper we address the advantage of screening a dynamic library by covalent capture in comparison with an approach in which the target is not covalently bound to the molecular receptor. The aim is the selection of recognition units for the binding of an anion (or polyanion) by relatively weak binding interactions, a situation typically found in supramolecular chemistry. To compare the two approaches, two model systems have been studied both based on the functionalization of a molecular platform, by reversible imine formation. In the case of the noncovalently bound substrate, the platform P1 is a trisubstituted benzene unit, 2,4,6-trimethylbenzene-1,3,5-tricarbaldehyde, to select: three recognition arms for the binding of the trisodium salt of benzene-1,3,5tricarboxylate. For the covalent-capture-based approach the platforms P2 and P4 are benzene derivatives with a tethered phosphonate target (tetrabutylammonium 2-formylphenyl ethylphosphonate) for the selection of a single recognition unit. The library of recognition elements comprises phenyl and ammonium-functionalized amines. We show that the selection of recognition units for the binding of the substrate with weak to medium, binding constants may encounter, by using a noncovalently bound substrate, serious problems. This is because the best conditions for the amplification of the library, that is, a large excess of variable recognition elements and target, lead also to competitive binding of the elements not bound to the platform, with the target. This may result in negligible amplification of the best-fit members of the library. In contrast, upon tethering the target to the platform and using the covalent-capture strategy for the selection of the recognition elements, significant amplification is observed, even for systems with much lower binding constants. Although competition with excess recognition units may also become an issue in the case of the tethered target, there is a way to overcome the problem by working at low concentrations.
- Martin, Marco,Gasparini, Giulio,Graziani, Matteo,Prins, Leonard J.,Scrimin, Paolo
-
scheme or table
p. 3858 - 3866
(2010/09/05)
-
