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| 2. |
- Csendes, Z., et al.
(author)
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Superoxide dismutase inspired Fe(III)-amino acid complexes covalently grafted onto chloropropylated silica gel - Syntheses, structural characterisation and catalytic activity
- 2013
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In: Journal of Molecular Structure. - : Elsevier BV. - 0022-2860. ; 1044, s. 39-45
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Journal article (peer-reviewed)abstract
- In this work the syntheses, structure and SOD activity of covalently grafted Fe(III)-complexes formed with various N- or C-protected amino acid ligands (L-histidine and L-tyrosine) inspired by the active site of the Fe SOD enzyme are presented. Chloropropylated silica gel was used as support to mimic the proteomic skeleton of the enzyme. Anchored complexes having uniform amino acids as well as their two-component mixtures have been prepared. The products were characterised by mid and far IR and Raman spectroscopies. SOD activities of the substances were determined via the Beauchamp-Fridovich test reaction. It was found that the preparation of covalently anchored Fe(III)-amino acid complexes was successful in many cases. The structures of the anchored complexes and the coordinating groups varied upon changing the conditions of the syntheses. All the covalently immobilised complexes displayed (in some instances appreciable) SOD activity. (C) 2012 Elsevier B.V. All rights reserved.
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| 3. |
- Csendes, Z., et al.
(author)
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Synthesis, structural characterisation, and catalytic activity of Mn(II)-protected amino acid complexes covalently immobilised on chloropropylated silica gel
- 2015
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In: Catalysis Today. - : Elsevier BV. - 0920-5861. ; 241, s. 264-269
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Journal article (peer-reviewed)abstract
- In this work the syntheses, structure, superoxide dismutase (SOD) activity and the catalytic use in the oxidative transformations of cyclohexene of covalently grafted Mn(II)-complexes formed with various C-protected amino acid (L-histidine, L-cysteine and L-cystine) ligands are presented. The structural features of the surface complexes were studied by EPR, X-ray absorption, and mid/far IR spectroscopies. The superoxide dismutase activities of the materials were determined in a biochemical test reaction. The obtained materials were used as catalysts for the oxidation of cyclohexene with peracetic acid in acetone. Covalent grafting and building the complex onto the surface of the chloropropylated silica gel were successful in all cases. It was found that in many instances the structures obtained and the coordinating groups substantially varied upon changing the conditions of the syntheses. All the covalently immobilised Mn(II)-complexes displayed superoxide dismutase activity and could catalyse the oxidation of cyclohexene. (C) 2014 Elsevier B.V. All rights reserved.
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| 4. |
- Ferencz, Zs, et al.
(author)
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Mechanochemical synthesis and intercalation of Ca(II)Fe(III)-layered double hydroxides
- 2016
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In: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596. ; 233, s. 236-243
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Journal article (peer-reviewed)abstract
- A mechanochemical method (grinding the components without added water - dry grinding, followed by further grinding in the presence of minute amount of water or NaOH solution - wet grinding) was used in this work for the preparation and intercalation of CaFe-layered double hydroxides (LDHs). Both the pristine LDHs and the amino acid anion (cystinate and tyrosinate) intercalated varieties were prepared by the two-step grinding procedure in a mixer mill. By systematically changing the conditions of the preparation method, a set of parameters could be determined, which led to the formation of close to phase-pure LDH. The optimisation procedure was also applied for the intercalation processes of the amino acid anions. The resulting materials were structurally characterised by a range of methods (X-ray diffractometry, scanning electron microscopy, energy dispersive analysis, thermogravimetry, X-ray absorption and infra-red spectroscopies). It was proven that this simple mechanochemical procedure was able to produce complex organic-inorganic nanocomposites: LDHs intercalated with amino acid anions.
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| 5. |
- Sranko, D., et al.
(author)
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A SEM, EDX and XAS characterization of Ba(II)Fe(III) layered double hydroxides
- 2011
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In: Journal of Molecular Structure. - : Elsevier BV. - 0022-2860. ; 993:1-3, s. 62-66
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Conference paper (peer-reviewed)abstract
- The structural characteristics of Ba-Fe double hydroxides were studied by various methods, such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX) fluorescence and X-ray absorption spectroscopies (XAS). It was verified that under hyperalkaline conditions (using 10 M or 20 M NaOH solution for precipitating the substances) layered double hydroxides could be prepared and the structure collapsed on heat treatment at 523 K. Important structural parameters could also be obtained through the quantitative analysis of the XAS spectrum of Ba3Fe-LDH made using 20 M NaOH for precipitating the material. (C) 2010 Elsevier B.V. All rights reserved.
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| 6. |
- Sranko, D. F., et al.
(author)
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Radiation induced topotactic [2+2] dimerisation of acrylate derivatives among the layers of a CaFe layered double hydroxide followed by IR spectroscopy
- 2013
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In: Journal of Molecular Structure. - : Elsevier BV. - 0022-2860. ; 1044, s. 279-285
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Journal article (peer-reviewed)abstract
- Various acrylates [E-phenylpropenoate, E-3(4'-nitrophenyl)propenoate, E-3(2',5'-difluorphenyl)propenoate, E-3(2'-thienyl)propenoate, E-3(4'-imidazolyl)propenoate or E-2,3-dimethylpropenoate] were successfully intercalated into Ca(II)Fe(III) layered double hydroxide (CaFe - LDH) verified by a range of instrumental methods. The possible arrangements for the organic anions were suggested on the basis of basal spacing data, layer thickness and the dimensions of the quantum chemically optimised structures of the acrylate ions. Using the acrylate CaFe LDHs as reactant-filled nanoreactors, photoinitiated topotactic [2 + 2] cyclisation reactions followed by IR spectroscopy could be performed with many representatives [E-phenylpropenoate-, E-3(4'-nitrophenyl)propenoate-, E-3(2',5'-difluorphenyl)propenoate- or E-3(2'-thienyl)propenoate-CaFe-LDHs] resulting in cyclobutane derivatives within the layers of the host material indicating that there were domains where the intercalated anions were in close proximity to each other and in proper arrangement for the reaction to occur. (C) 2012 Elsevier B.V. All rights reserved.
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| 7. |
- Varga, G., et al.
(author)
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Building, characterising and catalytic activity testing of Co-C-protected amino acid complexes covalently grafted onto chloropropylated silica gel
- 2015
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In: Journal of Molecular Structure. - : Elsevier BV. - 0022-2860. ; 1090, s. 138-143
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Journal article (peer-reviewed)abstract
- Co-C-protected amino acid (C-protected L-histidine, L-tyrosine, L-cysteine and L-cystine) complexes were covalently grafted onto chloropropylated silica gel, and the materials thus obtained were structurally characterised by mid/far IR and X-ray absorption spectroscopies. The superoxide dismutase-like activities of the substances were determined via the Beauchamp-Fridovich test reaction. It was found that covalent grafting and the preparation of the anchored complexes were successful in most cases. The coordinating groups varied upon changing the conditions of the syntheses. All materials displayed catalytic activity, although catalytic activities differed widely. (C) 2014 Elsevier B.V. All rights reserved.
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