1. Biotransformation of copper oxide nanoparticles by the pathogenic fungus Botrytis cinereaKatarina Vogel-Mikuš, Darko Makovec, Tamás Papp, Iztok Arčon, Johannes Teun van Elteren, Marjana Regvar, Eva Kovačec, 2017, original scientific article Abstract: Two plant pathogenic fungi, Botrytis cinerea and Alternaria alternata, isolated from crop plants, were
exposed to Cu in ionic (Cu2þ), microparticulate (MP, CuO) or nanoparticulate (NP, Cu or CuO) form, in
solid and liquid culturing media in order to test fungal response and toxic effects of the mentioned
compounds for the potential use as fungicides. B. cinerea has shown pronounced growth and lower levels
of lipid peroxidation compared to A. alternata. Its higher resistance/tolerance is attributed mainly to
biotransformation of CuO and Cu NPs and CuO MPs into a blue compound at the fungal/culturing media
interface, recognized by Cu K-edge EXAFS analysis as Cu-oxalate complex. The pronounced activity of
catechol-type siderophores and organic acid secretion in B. cinerea induce leaching and mobilization of
Cu ions from the particles and their further complexation with extracellularly secreted oxalic acid. The
ability of pathogenic fungus to biotransform CuO MPs and NPs hampers their use as fungicides. However
the results show that B. cinerea has a potential to be used in degradation of Cu(O) nanoparticles in
environment, copper extraction and purification techniques.
Found in: ključnih besedah
Keywords: copper, metal oxide nanoparticles, detoxification mechanisms, metal pollution, Cu-oxalate
Published: 23.08.2017; Views: 3494; Downloads: 0
 Fulltext (1,52 MB) |
2. Crystal habit modification of Cu(II) isonicotinate-N-oxide complexes using gel phase crystallisationJonathan Steed, Žygimantas Drabavičius, Katja Ferfolja, Dipankar Ghosh, Krishna Kumar Damodaran, 20, original scientific article Abstract: We report the crystallisation of three forms of copper(II) isonicotinate-N-oxide complex and their phase interconversion via solvent-mediated crystal to crystal transformation. The different forms of copper complex have been isolated and characterised by single crystal X-ray diffraction. Gel phase crystallisation performed in hydrogels, low molecular weight gels and gels of tailored gelator showed crystal habit modification. Crystallisation in aqueous ethanol resulted in concomitant formation of blue (form-I) and green (form-II/IV) crystals while use of low molecular weight gel results in selective crystallization of the blue form-I under identical conditions. Comparison of gel phase and the solution state crystallisation in various solvent compositions reveals that the blue form-I is the thermodynamically stable form under ambient conditions.
Found in: ključnih besedah
Summary of found: ...report the crystallisation of three forms of copper(II) isonicotinate-N-oxide complex and their phase interconversion via...
Keywords: copper(II) complex, gel phase crystallisation, crystal habit modification, isonicotinate-N-oxide, X-ray diffraction
Published: 08.11.2018; Views: 2650; Downloads: 0
Fulltext (968,24 KB) |
3. Effect of Na, Cs and Ca on propylene epoxidation selectivity over CuOx/SiO2 catalysts studied by catalytic tests, in-situ XAS and DFTJanvit Teržan, Matej Huš, Iztok Arčon, Blaž Likozar, Petar Djinović, 2020, original scientific article Abstract: This research focuses on epoxidation of propylene over pristine, Na, Ca and Cs modified
CuOx/SiO2 catalysts using O2. The selectivity of the reaction is analyzed using a combination
of catalytic tests, in-situ XAS and DFT calculations. The initially present subnanometer CuO
clusters are present in all catalysts which re-disperse/flatten during reaction. During catalytic
reaction, the Cu1+ becomes the predominant oxidation state. There is no correlation between
propylene oxide (PO) selectivity and copper oxidation state. DFT analysis of the propylene
reaction pathway revealed that Na, Cs, and Ca addition decreases the bonding strength of
propylene to CuO and decreases the O2 activation barrier, while simultaneously increase the
exothermicity of O2 dissociation. The Na induced Cu-O bond modification decreases the
activation barrier from 0.87 to 0.71 eV for the oxametallacycle (OMC) ring closure (first step
in the reaction pathway favoring selectivity towards PO) compared to pristine 5Cu catalyst.
At the same time, we observed an increase (from 0.45 to 0.72 eV) of the barrier for the
abstraction of allylic hydrogen. The opposite effect is achieved by Ca addition: the activation
barrier for OMC ring closure increases to 1.08 eV and that for allylic hydrogen stripping
decreases to 0.16 eV.
Found in: ključnih besedah
Summary of found: ...no correlation between
propylene oxide (PO) selectivity and copper oxidation state. DFT analysis of the propylene
reaction...
Keywords: Alkali modification, propylene epoxidation, reaction mechanism, copper oxide, activation barrier.
Published: 05.06.2020; Views: 1992; Downloads: 0
Fulltext (22,78 MB) |
4. The role of hydroxyl ions in the evolution of optical nonlinearity of CuORiya Sebastian, Mohanachandran Nair Sindhu Swapna, H. V. Saritha Devi, Vimal Raj, Misha Hari, Sankaranarayana Iyer Sankararaman, 2019, original scientific article Found in: ključnih besedah
Summary of found: ...hydroxyl ions, optical nonlinearity, Z scan, copper oxide...
Keywords: hydroxyl ions, optical nonlinearity, Z scan, copper oxide
Published: 05.07.2022; Views: 369; Downloads: 31
Fulltext (1,61 MB)
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