Wyniki wyszukiwania - Biblioteka Nauki

1

Supramolecular complexes of podand ligands with xenon

100%

Gierczyk B. , Pankiewicz R.

Open Chemistry

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2014

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tom 12

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nr 5

624-634

EN

Formation of stable complexes between xenon and podand polyoxyethylene ligands was ascertained. The complexation process was studied by 129Xe NMR titration, NMR diffusiometry and heteronuclear NOE measurements. The ligands studied form a 1:1 complexes with Xe(0). Their stability constants depend on the ligand structure, i.e., polyoxyethylene chain length, number of complexating polyether units and the topology of the anchoring centre.

2

Bifunctional sulfur-silicon podands as new nucleophilic ionophores in acyl transfer reactions. Influence of monovalent cations on the reaction kinetics

80%

ŁLęska B. , Schroeder G. , Gierczyk B. , Rybachenko V.

Open Chemistry

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2006

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tom 4

|

nr 2

351-362

EN

Two bifunctional sulfur-silicon nucleophilic ionophores 3-(trimethoxysilyl)-propanethiol (Nu1) and 3-(tri-2-methoxyethoxysilyl)-propanethiol (Nu2) were used as reagents in the acyl transfer reaction studied by kinetic methods. Nuclear magnetic resonance (NMR) and electro-spray ionisation mass spectrometry (ESI MS) were used for determination of the stoichiometry and stability constants of the complexes made by the podands and lithium or sodium ions in acetonitrile solution.

3

Impact of selected supramolecular additives on the initial electrochemical lithium intercalation into graphite in propylene carbonate

80%

Walkowiak M. , Waszak D. , Gierczyk B. , Schroeder G.

Open Chemistry

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2008

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tom 6

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nr 4

600-606

EN

Impact of silicon tripodand-type electrolyte additives and graphite pre-treatment agents on the electrochemical intercalation of lithium cations into graphite was investigated. Addition of Si-tripodand-type silanes to propylene carbonate-based electrolytes was found to suppress detrimental solvent co-intercalation and graphite exfoliation. Similar effects were observed for graphite pre-treated with the reported silane agents. It was observed that the presented supramolecular additives allow for the formation of effective passive layers on graphite during first charging, and thus can be considered as novel low-cost film-forming components for rechargeable lithium batteries. [...]

4

Unexpected formation of [M]2+from [M+CuCl+H]2+ions under CID conditions, where M is a molecule of 3,5-bis(2,2’-bipyridin-4-ylethynyl)benzoic acid or its methyl ester

61%

Frański R. , Zalas M. , Gierczyk B. , Cegłowski M. , Schroeder G. , Kozik T. , Hoffmann M.

Open Chemistry

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2015

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tom 13

|

nr 1

EN

[M+CuCl+H]2+ ions were generated using electrospray ionization (ESI); where M is a molecule of 3,5-bis(2,2’-bipyridin-4-ylethynyl)benzoic acid or its methyl ester (1 and 2, respectively). The ions were subjected to CID-MS/MS analysis. It was found that their gas phase decomposition lead to the formation of rare di-cations [M]2+, namely [1]2+ and [2]2+ ions. The formation of [1]2+ ion from [3+H+CuCl]2+ ion in the second fragmentation, where 3 is ethyl ester of 3,5-bis(2,2-bipyridin-4-ylethynyl)benzoic acid, was also observed since in the first fragmentation step the loss of ethylene molecule from [3+H+CuCl]2+ ion took place. To the best of our knowledge, it is the first time that [M]2+ ions formation from respective metal complexes has been reported. It is also unusual that formation of [M]2+ ions is not accompanied by formation of [M]+∙ ions. Furthermore, as expected, theoretical calculation and electron ionization mass spectra show that 1 and 2 are not especially prone to form [M]2+ ions. Thus formation of [M]2+ ions under CID conditions is very surprising.

5

Electrospray ionization mass spectrometric study of mercury complexes of N-heterocyclic carbenes derived from 1,2,4-triazolium salt precursors

61%

Frański R. , Gierczyk B. , Schroeder G. , Pieper S. , Springer A. , Linscheid M.

Open Chemistry

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2007

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tom 5

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nr 1

316-329

EN

By mixing 1,2,4-triazolium salts (precursors of N-heterocyclic carbenes 1–6) with mercury acetate, a number of complexes have been obtained under electrospray ionization condition. Carbenes 1 and 2 contain one carbene center; therefore, they are able to bond only one mercury cation. Carbenes 3–5 contain two carbene centers; therefore, they can bond two mercury cations. Mercury complexes of 1–5 always contain an acetate anion attached to a mercury cation. Carbene 6 also contains two carbene centers; however, its structure allows formation of a complex containing mercury bonded simultaneously to both centers, therefore, the complex that does not contain an acetate anion. The MS/MS spectra taken for complexes of carbenes 1–5 have shown formation of a cation corresponding to N1 substituent (adamantyl or benzyl), and those of complexes of carbenes 3–5 (doubly charged ions) have also shown the respective complementary partner ions. Mercury complex of 2 has yielded some other interesting fragmentation pathways, e.g. a loss of the HHgOOCCH3 molecule. The fragmentation pathway of the mercury complexes of 6 was found to be complicated.

6

1H NMR and spectrophotometric study of alkaline metal ion complexes with N-dansyl aza-18-crown-6

61%

Ossowski T. , Sulowska1 H. , Karbowiak T. , Zarzeczanska D. , Gierczyk B. , Schroeder G.

Open Chemistry

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2006

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tom 4

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nr 1

13-28

EN

Formation of complexes of A18C6-Dns and metal cations (Ca2+, Sr2+, Ba2+ and Mg2+) in acetonitrile has been studied by NMR, absorption and fluorescence spectroscopy and PM5 semi-empirical methods. A18C6-Dns forms stable complexes with Ca2+, Sr2+ and Ba2+ cations. The stability constants of various complexes are determined by different methods and their structures are visualised by the PM5 semi-empirical calculations.

7

Copper complexes formed by 3,5-bis(2,2′-bipyridin-4-ylethynyl)benzoic acid and its methyl and ethyl esters as studied by electrospray ionization mass spectrometry

61%

Frański R. , Kowalska M. , Czerniel J. , Zalas M. , Gierczyk B. , Cegłowski M. , Schroeder G.

Open Chemistry

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2013

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tom 11

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nr 12

2066-2075

EN

Electrospray ionization mass spectrometry was used to study the complexes of ligands containing two bipyridine units, namely 3,5-bis(2,2-bipyridin-4-ylethynyl)benzoic acid (1) and its methyl and ethyl esters (2, 3), with copper cation, with CuCl2 as a source of copper. It was found that the type of complexes formed strongly depends on CuCl2 concentration. At lower CuCl2 concentration, the detected complexes were rather simple and some of them were formed upon electrospray ionization conditions e.g. ions [22+Cu2]2+ and [32+Cu2]2+ (complexes ligand-Cu(I) of stoichiometry 2:2) which are analogical to the well known, for quaterpyridine, helical complexes. At higher CuCl2 concentration, the detected complexes were more complicated, and most of them contained copper cations bridged by chlorides. The largest ions were [L2+Cu4Cl6]2+. The CID MS/MS spectra of these ions allowed determination of their mass spectrometric fragmentation pathways and as a consequence their structure elucidation. [...]