Four silver-based coordination polymers, {Ag(L)2(BF4)}∞ (1), {Ag(H2BTC)(L)·(H3BTC)}∞ (2), {Ag2(H2BTEC)(L)2·3.33H2O}∞ (3), and Ag(H25SSA)(L)∞ (4), were synthesized using ...thiomorpholine-4-carbonitrile (L) as the primary ligand and three aromatic polyoxoacids as coligands: trimesic (H3BTC), pyromellitic (H4BTEC), and 5-sulfosalicylic acid (H35SSA). Compounds 1 and 3 are two-dimensional, while 2 and 4 are one-dimensional. L acts as a bis-monodentate ligand, while the Ag(I) ion is three-coordinated in 2 and four-coordinated in all of the other compounds. The tetrahedral coordination of Ag(I) in 3 leads to an almost complete absence of intermolecular interactions with the metal center. All compounds show reasonable photocatalytic activity for photocatalytic degradation of mordant blue 9 dye, with reaction rates in the 0.036–0.056 min–1 range. Changes in the reaction rates can be correlated with the type and coordination of the coligand. Complex 3 exhibits photoluminescence at 77 K, while 4 exhibits photoluminescence at both room temperature and 77 K. Luminescence lifetimes indicate electronic transitions of singlet parentage, where transitions are allowed. A TD-DFT study determined the contributions of individual singlet–singlet electronic excitations to the fluorescence, indicating that metal– intraligand transitions are responsible for luminescence in both complexes.
Pt(II) and Pd(II) complexes (1 and 2, respectively) with thiomorpholine-4-carbonitrile (TM-CN), an N-substituted thiomorpholine derivative, were synthesized from tetrachlorido precursors in water. ...Structural analysis has shown that 1 represents the first monomeric metal complex with this ligand type with an axial M–S bond with respect to the TM-CN ring chair conformation, while in 2 a typical equatorial M–S bond position with respect to the ring chair conformation was observed. A detailed DFT investigation revealed that axial conformers are more stable for molecular forms of both metals, while intermolecular interactions in the crystals stabilize the axial conformer for Pt(II) and the equatorial conformer for Pd(II). The magnitude of this stabilization in the case of 2 is large enough to change the most stable axial conformer in the molecular form to the equatorial conformer in the crystal. Further investigation of the strength of individual intermolecular interactions revealed significant differences of some interactions between the two structures. The likely cause of the difference in the crystal structures of experimentally obtained complexes is the fact that 1 and 2 exhibit different dominant interactions: C–H/M and C–H/S are more dominant in 1 and C–H/Cl interactions are more dominant in 2. In addition, DFT calculations have shown that while the axial position of the Pt–S bond with respect to the ring chair conformation results in a significantly shorter C–H/Pt interaction distance than that in the hypothetical equatorial conformer, there is very little difference in C–H/Pd interaction distances in conformers with axial and equatorial positions of Pd–S bond with respect to the ring chair conformation.
An octahedral complex of Zn(II) with a ligand from a class of pyridine- based 1,3-selenazolyl-hydrazones was synthesized and characterized by IR and NMR spectroscopy and single crystal X-ray ...diffraction analysis. The purity of the complex was confirmed by elemental analysis. Two ligands are coordinated in the neutral NNN-tridentate form forming a complex cation, while the positive charge is neutralized by ZnCl42-. Complex crystallizes in monoclinic C2/c space group with the Zn atoms situated in a special position. The packing features of the novel complex were analyzed using Hirshfeld surfaces, construction of 2D pseudosymmetric plot and DFT quantum mechanical calculations and compared with the previously published sulfur-based isostere. The key difference in the structures, imposed by replacement of sulfur with selenium, were identified.
Two square?planar complexes, PtLCl (1) and PdLCl (2), were synthesized with quinoline-2-carboxaldehyde thiosemicarbazone ligand (HL), and characterized by IR and NMR spectroscopy and single crystal ...X-ray diffraction analysis. In both complexes, L- is coordinated tridentately via the same donor atom set, while the fourth coordination site is occupied by a chloride ion. However, the complexes are not isostructural due to different types of non-covalent intermolecular interactions. These interactions were analyzed using Hirshfeld surfaces and two-dimensional fingerprint plots.
Many articles in the literature deal with horseradish peroxidase (HRP) biomineralization, but none pay attention to the isoenzyme composition of commercial HRP or the influence of the carbohydrate ...component of the protein molecule on the biomineralization process. To study the impact of these factors, we performed periodate oxidation of commercial HRP and a purified HRP-C isoform for biomineralization within ZIF-8. With purified HRP, enzyme@ZIF-8 biocomposites with higher activity were obtained, while periodate oxidation of the carbohydrate component of both commercial HRP and purified HRP-C yields biocomposites with very high activity in acetate buffer that does not degrade the ZIF-8 structure. Using acetate instead of phosphate buffer can prevent the false high activity of HRP@ZIF-8 biocomposites caused by the degradation of ZIF-8 coating. At the same time, purification and especially oxidation of the carbohydrate component of enzymes prior to biomineralization lead to significantly improved activity of the biocomposites.
Four silver-based coordination polymers, {Ag(L1)
2
NO
3
}
∞
(
1
), {Ag(L1)
2
ClO
4
}
∞
(
2
), {Ag(L2)
2
NO
3
·H
2
O}
∞
(
3
) and {Ag(L2)
2
ClO
4
}
∞
(
4
), were synthesized using the ...thiomorpholine-4-carbonitrile (L1) and piperazine-1,4-dicarbonitrile (L2) ligands. Compounds
1
and
2
are two-dimensional, while
3
and
4
are three-dimensional. L1 and L2 are 1,4-bis-monodentate ligands in all compounds, while Ag(
i
) ions are four-coordinated in a slightly distorted tetrahedral geometry. Topological analysis in standard representations suggests that underlying nets in
1
and
2
have an
sql
topology, while
3
and
4
exhibit a
dia
topology. Thermal analysis shows that
3
loses crystalline water at room temperature, while other compounds show good thermal stability. All compounds show good photocatalytic activity for photocatalytic degradation of the mordant blue 9 dye, with reaction rates in the range 0.029 to 0.061 min
−1
. The best result was obtained for compound
4
, which can be correlated to its largest lattice volume.
The reaction of the thiomorpholine-4-carbonitrile and piperazine-1,4-dicarbonitrile ligands afforded four Ag(
i
) coordination polymers with excellent photocatalytic activity in the degradation of the mordant blue 9 dye.
Zeolitic imidazolate framework-8 (ZIF-8) is widely used as a protective coating to encapsulate proteins via biomimetic mineralization. The formation of nucleation centers and further biocomposite ...crystal growth is entirely governed by the pure electrostatic interactions between the protein’s surface and the positively charged Zn(II) metal ions. It was previously shown that enhancing these electrostatic interactions by a chemical modification of surface amino acid residues can lead to a rapid biocomposite crystal formation. However, a chemical modification of carbohydrate components by periodate oxidation for glycoproteins can serve as an alternative strategy. In the present study, an industrially important enzyme glucose oxidase (GOx) was selected as a model system. Periodate oxidation of GOx by 2.5 mM sodium periodate increased negative charge on the enzyme molecule, from −10.2 to −36.9 mV, as shown by zeta potential measurements and native PAGE electrophoresis. Biomineralization experiments with oxidized GOx resulted in higher specific activity, effectiveness factor, and higher thermostability of the ZIF-8 biocomposites. Periodate oxidation of carbohydrate components for glycoproteins can serve as a facile and general method for facilitating the biomimetic mineralization of other industrially relevant glycoproteins.
Analyzed structures of silver-based monomer and coordination polymer with organic thiocyanate represent an example where the nature of (non)coordinated ions were found to have the profound influence ...on coordination mode of the ligand and consequently crystal packing. The monomer showed an excellent antiproliferative activity in tested human tumor cell lines.
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The first complexes of 2-pyridylthiocyanate (L) and silver nitrate (1) and perchlorate (2) were prepared and characterized by a single crystal X-ray analysis. The common structural motif of both 1 and 2 is coordination of two L molecules via pyridine nitrogen atom to Ag(I). In order to properly describe the nature of coordinative bonds in 1 and 2, as well as crystal packings in respective structures, a Quantum Theory of Atoms in Molecule topological analysis was performed. Coordinated nitrate ion provides more electron density to Ag(I) in comparison to perchlorate ion. Additional electron density in the case of 2 was provided by the coordination of third L molecule via thiocyanate nitrogen atom resulting in a 1D polymeric structure. Detailed computational analysis of intermolecular interactions, as well analysis of interactions between pyridine ring and –SCN group was performed. Antiproliferative activity of monomeric compound 1 was found to be better than of cisplatin on three out of four studied human cancer cell lines. Docking studies indicate intercalation as a major binding mode of 1 to DNA, while human serum albumin was revealed as possible carrier for distribution of 1 in the blood stream.
The beginning of the 21st century marked an evolutionary "leap" in Internet technology - the transition from static web pages whose content was determined solely by their creator to dynamic, ...interactive user-created web pages and the emergence and proliferation of social networks as a special and multi-purpose cyber info-sphere.In such a new and dynamic environment, naturally the need for new ways of functioning of public relations has emerged, finding new approaches and methods that would successfully fit into the new digital environment and take advantage of all the newly created potential. This next evolutive stage of the Internet - Web 2.0 brought interactive access web-pages, blogs, social networks/media, targeted advertising and pod-casts have become new and vital fields of contemporary PR. The new interactive technologies have enabled not only more accurate identification of target groups but also direct access to the collection of unimaginable quantity and quality of data that describes not only groups but individuals as well. This quantum leap in knowledge of target audiences made possible more precise "tailoring" of messages for each of them, thus dramatically increasing the effectiveness of these messages. This paper will analyze the principles, functions and possibilities of modern digital public relations, the methods and tools for it`s application as well as practical examples.
The goal of market communications is for the advertiser to convince the recipient, i.e. the consumer, to accept his commercial offer and to choose his among the multitude of similar, competing ...products or services. Advertising is a key phase of the marketing process and success on the market depends on its effectiveness. In order to carry out persuasion, it is necessary to know all the factors in the communication process and their characteristics. It is necessary to analyze all the relevant features of the message sender, the transmission channel and most of all the receiver in the process of audio-visual communication using theories that explain the process of communication, theories that can be used to determine and predict the reactions of recipients to various types and forms of information, their psychological and motivational factors in the decision-making process and determining their practical application to market persuasion. Determining the characteristics and attitudes of consumers, their motivational mechanisms and needs and using or changing them or creating new ones by the market communicator-advertiser is a key condition that needs to be fulfilled in order to achieve successful persuasion, i.e. marketing of a product, service or idea. For this purpose, the application of psychological mechanisms in advertising and persuasion based on them is the only effective tool and as such a necessary element of persuasion through audio-visual media. Emotional factors -humor, fear, pleasure and Ego have a key influence on the effectiveness of persuasive commercial messages and their use in market communications is significant.
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