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Electrochemically Investigated pH-dependent Redox Properties of Copper Complexes of Azamacrocyclic Ligands
Koláčná, Lucie ; Maďar, M. ; Kubíček, V. ; Ludvík, Jiří
Investigated Cu(II) complexes are based on plain or cross-bridged cyclam. The\nelectrochemically inactive cyclam was modified by carboxylate, phosphonate, or phenolate\npendant arms. Cu(II) represents the main redox center of the complexes. Modification of the\nligand causes a changed pattern of complex redox response in buffered aqueous solution.\nIrreversible Cu(II) reduction results in complex decomposition to amalgamated copper and\nligand in excess. After Cu(0) electrochemical in situ re-oxidation, copper and ligand are recomplexed.\nComplexes undergo isomerization, accelerated by increasing the temperature. The\ninfluence of pH on complex isomerization and the reversibility of its reduction was described.
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Redox Properties of Conjugated Phosphole Derivatives – Electrochemical Study
Koláčná, Lucie ; Polák, P. ; Tobrman, T. ; Ludvík, Jiří
The study describes pentasubstituted phospholes with a π-conjugated arms in positions 2 and 5 of the phosphole ring. According to the expectations, substituents with electron-donating groups led to lower oxidation potentials, the presence of electron-withdrawing groups shifts the reduction potential to less negative values. Because all studied phospholes have multiple substituents of both types, their resulting potentials represent the sum of their influences. Moreover, since many of the studied compounds have two redox centers (phosphole moiety itself and the pi-conjugated arm), their locations were determined and intramolecular interactions were followed, because substituents which can be conjugated with the π-system of phosphole are able to extend the delocalized π-system resulting in stabilization of primary redox intermediates. Chemical modification of phospholes using various combinations of substituents can set the desired electrochemical properties of studied molecules.
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Electrochemistry of Phospholes
Koláčná, Lucie ; Liška, Alan ; Ludvík, Jiří
Seventeen pentasubstituted phospholes with expected application in organic electronics were\nsynthesized and characterized electrochemically and by UV-vis spectra. Quantum chemical\ncalculations ofredox potentials and HOMO-LUMO energies were performed and experimental\nand theoretical data were successfully correlated. Tuning of redox properties can be achieved\nby combination of induction and resonance effects of substituents, extension / diminution of\nthe pi- delocalized system and by steric changes which affect intramolecular electron\ncommunication.
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Hodnocení vlivu doplňkových závlah s přídavkem bioaditiv v kulturách zeleniny
Koláčná, Lucie
The aim of this study was to evaluate the influence of the bioaditivs on the pepper (Capsicum annuum). For a given experiment were selected products based on bacteria strains , exactly : Azospirillum brasilense K2012 242/9 , Azospirillum largimobile B41 K2012, K2009 Leuconostoc mesenteroides 25/4 , Pseudomonas chlororaphis K2009 13/4, Pseudomonas lundensis K2009 9/4-B and algal bio-preparation R49S/2011 companies Rawat . Furthermore, the variant treated with arbuscular fungi , the inoculum was composed of Glomus intraradices BEG140, Glomus claroideum BEG210 , Glomus microaggregatum BEG56, Glomus intraradices S7, Glomus versiforme a saprophytic fungus Trichoderma harzianum. Next experiment contained a variant treated with phenyl and seven untreated control variant. The aim of this study was to evaluate the influence of the additives, namely the action of bacterial additives on the yield and nutritional parameters. The entire experiment was carried out in the Slovak village Závod. The results were analyzed statistically using programme STATISTICA 12. Based on the obtained results, it is evident that the variant algae + bacteria was found to increase revenues , compared to control treatment. The highest yield was achieved in the variations of Mycorrhiza + Trichoderma. The nutritional parameters were determined total antioxidant capacity in fruits, vitamin C and dry matter content . High levels of vitamin C were achieved in variants Phenyl 7, at least variants Algae + bacteria between these variants was statistically significant difference of almost 50 %. Total antioxidant capacity was clearly highest in control untreatment variant. Among the variants and Algae Control + bacteria was 37 %. In determining the content of dry matter was found that a minimum content of dry matter showed variant Algae + bacteria, 4.75%.
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