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Recognition Material for Cu(II) Ions Based on Photoinduced Electron Transfer and Surface Plasmon Resonance Effects

Orłowska M., Kledzik K., Mroczkiewicz M., Ostaszewski R., Kłonkowski A. M.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 6

1289-1293

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Enhancement of 5D4 → 7FJ Luminescence in Tb(III) in the Vicinity of Ag Nanoparticles in Silica Xerogel

Lipowska B., Kledzik K., Kłonkowski A. M.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 6

1295-1298

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Optical recognition elements. Macrocyclic imidazole chromoionophores entrapped in silica xerogel

Kledzik K., Jamrógiewicz M., Gwiazda M., Wagner-Wysiecka E., Jezierska J., Biernat J. F., Kłonkowski A. M.

Materials Science Poland

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2007

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Vol. 25, No. 4

1041--1051

EN

Materials containing new chromoionophores consisting of crown residue and azole moiety as parts of macrocycles were encapsulated by the sol-gel procedure in silica xerogel matrices and proposed as chemical recognition elements especially for such metal ions as Li+, Cs+ and Cu2+. Action of these recognition elements is in principle based on changes of reflectance. The recognition elements containing 21- membered chromogenic derivatives of unsubstituted imidazole and 4-methylimidazole are able to distinguish in aqueous solution whether the Li+ concentration ratio is lower or higher than 1. In the case of Cu2+ complexes with 18-membered macrocyclic chromoionophore in which phenol residue was replaced by imidazole and 21-membered chromogenic derivative of 4-methylimidazole, values of the EPR parameters g and A suggest participation of two oxygen and two nitrogen atoms of the ligand in the equatorial plane of the tetragonally distorted octahedral environment of the central ion.

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Zastosowanie spektroskopii TOF-SIMS w charakterystyce katalizatorów Pd/SiO2 otrzymanych metodą zol-żel

Karski S., Ludomirska I., Proga H., Szynkowska M.I., Witońska I., Kłonkowski A.M., Kledzik K.

Przemysł Chemiczny

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2006

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T. 85, nr 1

33-37

PL

Zbadano wpływ warunków preparatyki katalizatorów Pd/SiO2 otrzymanych metodą zol-żel na ich aktywność i selektywność w procesie redukcji aldehydu krotonowego. Do analizy powierzchni katalizatora użyto spektrometru TOF– SIMS, co umożliwiło wizualizację powierzchni, określenie składu chemicznego oraz segregację warstw powierzchniowych katalizatora w zależności od temperatury kalcynacji i redukcji, i w konsekwencji dobranie optymalnych warunków preparatyki.

EN

Catalyst activity and selectivity were tested in the redn. (100°C/2 hrs.) of crotonaldehyde satd. vapors in 0.03 l. H2/ min in relation to the 5%Pd/SiO2 prepn. history, esp. to calcination at 300, 500, or 700°C in Ar and at 300 or 500°C in H2 just before the reaction. The 500 and 300°C, resp., resulted in Pd distributed uniformly on the SiO2 surface, a factor crit. for catalyst’s high activity. TOF-SIMS found CH3+, CH3O+, C2H5, and SiCH3+ on the catalyst surface, but calcination at 500 or 700°C removed most of the org. fragments. The H2-treatment at 500–700°C, resulted in Pd clusters nonuniformly distributed (TOF–SIMS) on the surface and in a less active catalyst.

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Functions of Eu3+ ions in materials with CdS nanoparticles and oxide matrices

Kłonkowski A.M., Szałkowska I.

Materials Science Poland

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2005

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Vol. 23, No. 1

253--260

EN

CdS semiconductor nanoparticles are used to improve the luminescence properties of europium(III) -doped matrices such as silica xerogel and silica nanoparticles, both prepared by a sol-gel method as well as zeolite NaY. The impregnation of CdS nanosized clusters on an Eu3+-doped matrix enhances the luminescence of both dopants. Additionally, the luminescence of the materials can be improved by thermal treatment and by changing the Eu3+/CdS molar ratio. Eu3+ emission spectra show changes in the intensities of the bands at 595 and 612 nm, depending on the structural order of the oxide matrices.

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Luminescent materials, recognition phases of the chemical sensors and heterogeneous catalysts prepared by sol-gel method

Kłonkowski A. M.

Materials Science

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2002

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Vol. 20, No. 1

57-70

EN

The sol-gel process enables one to prepare oxide xerogels at room temperature. By using this method, it is possible to encapsulate a wide variety of organic, complex (organometallic) molecules and metallic nanoparticles stabilized by organic ligands in the inorganic or inorganic/organic hybrid matrix. Studies of this new type of inorganic/organic composite have evolved towards the deliberate doping of the supramolecular species. This review gives three examples of how doped xerogel materials prepared by the sol-gel method are emerging as an important means of producing new materials. The first part of this review is devoted to luminescent materials which are based on the antenna effect and are composed of Eu(III) complex (luminescence centre) entrapped in xerogel matrix. In this case results of the experiments concerning the coordination sphere composition show that a cryptand ligand with aromatic groups and an aromatic co-ligand, settle efficient action the antenna effect and isolate the central ion from each efficient quenchers, as e.g. water molecules. Secondly, silica xerogel samples with entrapped series of three fluorescent chemosensors of the Ant-R-Ant type, where Ant is an anthryl group and R is a receptor (spacer) with donor atoms, were prepared as chemical recognition phases. The recognition phase with fluorosensor of the type Ant- N-O-O-N-Ant, where N and O are donor atoms, can be regenerated many times and seems to be most promising system for the fluorescent chemical sensor. In the third part of this paper, ligand protected metal nanoclusters as immobilized catalysts are the point of interest. This type of heterogeneous catalysts are much less investigated than the bare metal particles on supports. The main interest is focused on the function of the ligands.

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Correlation between spectral properties and optical basicity for oxide gels doped with chromium(II) ions.

Kłonkowski A.M., Widernik T., Biczkowski M.

Optica Applicata

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2000

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Vol. 30, nr 4

503-508

EN

For oxide xerogels of the types: Na/sub 2/O-B/sub 2/O/sub 3/-SiO/sub 2/ and SiO/sub 2/-TiO/sub 2/ prepared by the sol-gel procedure a correlation between one of the absorption bands of Cr/sup 3+/ ion (attributed to the /sup 4/A/sub 2g/(F) to /sup 4/T/sub 2g/(F) transition) and theoretical optical basicity has been found. The experimental results show that Cr/sup 3+/ ion can play the role of basicity probe in the Lewis sense for oxide xerogels. Additionally, its band position can be a relative measure of water content in the same material.

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Ład w bezładzie, czyli kompleksy jonów metali przejściowych w szkłach i żelach tlenkowych

Kłonkowski A.M.

Wiadomości Chemiczne

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1998

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[Z] 52, 1-2

57-85

EN

The most basic difference between crystalline and non-crystalline solids is that a long range order (LORO) in the distribution of atoms (ions) or molecules exists only in crystalline materials [1]. This is indicated by diffraction patterns: the ideal crystal (the first extreme case) shows reflectants whose location and intensity obey three Laue conditions. The second extreme case is an ideally random structure. Scattering of radiation is impossible in the case of an ideally homogenous medium. Any real substance, including non-crystalline materials is inhomogenous regardless of its form or scale. Thus glasses can be thought of as assemblies of microcrystals (i.e. microcrystallites or paracrystals). Strain introduced due to lattice mismatch at grain boundaries, the presence of a disordered interfacial or matrix region, and defects such as dislocation, or stacking faults can be assumed to give rise to departures from periodicity at distances smaller than the average grain size [10]. In this sense glasses are interesting in the supramolecular science because they are intermediate objects in the way from random to organized matter [5]. The object of this article are such amorphous materials as inorganic oxide glasses with structural groups YO4, where Y = Si, P, and organically modified silicate gels. Among the studied glasses are ones of the type : R2O-SiO2 and R2O-Al2O3-SiO2, where R represents alkali atom (Li to Cs) [23, 25, 27], as well as M(II)O-P2O5, where M(II) is an alkaline earth atom (Mg to Ba) [28, 29, 32, 33]. Undoped glasses and those doped with copper (II) ions were investigated. These metal ions have played the role of probes. All the vitreous systems are classified according to their theoretical optical basicity [lambda] cal proposed by Duffy and Ingram [34]. Thanks to this method one can methodically observe and sensibly interpret changes of real measures of basicity as molar refractivity of oxide ions Ro (see Figs 9 and 10a), the so-called Imagawa's basicity (Fig.10b) and other physical and chemical properties of oxide glasses (Fig.11). The studied glasses are also classified according to their bond nature (Fig. 6)., taking into account their proximity to the onset of metallization [4]. Attention is also focused on the mixed alkali effect [22, 24]. A full understanding of the properties of colloids calls upon a wide range of physical and chemical ideas, while the multitude of colloidal systems presented to us in nature, and familiar in modern society, exhibits a daunting complexity. On the experimental side there is an ever-increasing emphasis on the application of modern physical techniques to colloidal problems. Colloid science is thus a truly interdisciplinary subject [3]. In the case of the xerogels there are described Cu(II) complexes existing on surface and in interior of the material [59-63]. Moreover, silica xerogels with immobilized supramolecular ligands show intensive luminescence (Fig. 17) which is effectively quenched by Cu(II) ions [64].