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Synergizm kompleksów metaloorganicznych z półprzewodnikami do fotokatalitycznego generowania wodoru

Grabowska-Musiał Ewelina

Wiadomości Chemiczne

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2024

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[Z] 78, 3-4

263--278

EN

Currently, considerable attention is paid to durable, stable and energy-saving systems for photocatalytic water decomposition. Traditional photocatalytic systems are mainly based on semiconductor materials surface-modified with noble metals or inorganic cocatalysts. Recently, significant attention has been paid to hybrid systems in which semiconductor materials are integrated with metal complexes, which seem to be an effective strategy for constructing efficient photocatalytic systems for water decomposition. This review focuses on examining the possibility of obtaining photoactive materials by integrating semiconductors with compounds of various metal ions: platinum, nickel and cobalt. The aim of such integration is to increase the efficiency of hydrogen production from water and obtain the so-called "green energy".

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Funkcjonalizowane klatkowe silseskwioksany : wybrane strategie syntezy i właściwości koordynacyjne na przykładzie metali 13 grupy

Szybisty Aleksandra, Wytrych Patrycja, Ejfler Jolanta, John Łukasz

Wiadomości Chemiczne

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2021

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[Z] 75, 3-4

293--318

EN

Completely condensed POSS compounds have a cage structure built of Si-O bonds, which makes their electronic properties similar to those of silica and silicates. Moreover, due to their relatively inelastic structure, they impose a coordination geometry on the metal atom, imitating the geometry imposed by silica. Due to the above-mentioned properties, homogeneous models based on silsesquioxanes may not only allow for a better understanding of the nature of heterogeneous catalysts at the molecular level, but also may act as valuable catalysts themselves. Many coordination compounds of main group metals, transition metals and lanthanides have already been obtained. From among the group 13 metals of which this work is concerned, coordination entities of boron, aluminum, gallium, thallium, and indium have been prepared and analyzed so far. They turned out to be suitable models for heterogeneous catalysts, in some cases showing catalytic properties themselves.

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Zastosowanie analizy termicznej do badania związków koordynacyjnych

Jabłońska-Wawrzycka A., Zienkiewicz M., Barszcz B.

Aparatura Badawcza i Dydaktyczna

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2011

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T. 16, nr 2

99-105

PL

Analiza termiczna znajduje zastosowanie jako metoda badawcza zjawisk fizycznych oraz reakcji chemicznych zachodzących w próbce substancji wskutek zmian temperatury w czasie. W swojej pracy wykorzystujemy metodę termograwimetryczną do badania trwałości termicznej i potwierdzenia składu połączeń koordynacyjnych metali przejściowych z pochodnymi pirydyny i imidazolu. Przeprowadzona analiza TG przykładowych kompleksów wykazała bardzo dobrą korelację wyników z danymi strukturalnymi i potwierdziła słuszność zaproponowanych wzorów sumarycznych oraz pozwoliła przewidzieć prawidłowo wzory strukturalne.

EN

Thermal methods of analysis are widely used for indicating thermal stability, thermal decomposition and other properties of solid compounds. In this work we report thermal behavior of exemplary complexes with pyridine and imidazole derivatives as the ligands. The results of the thermal analysis correlate very well with the data of CHN, IR and X-ray diffraction methods.

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Efektywność grup donorowych nukleotydów w reakcjach z jonami metali w układach podwójnych i potrójnych z udziałem tetramin

Gąsowska A.

Wiadomości Chemiczne

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2007

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[Z] 61, 5-6

339-359

EN

Nucleotides, being multifunctional ligands with donor nitrogen and oxygen atoms, take part in the majority of selective and specific processes occurring in nature [1-15]. It has been established that nucleotides react with the polyamines (biogenic amines) present in the living organisms and take part in genetic information transfer [16-24]. Nucleotides are composed of a purine or pyrimidine base, sugar residua and phosphate groups (Fig. 1) [25-27]. Each of the three components have potential centres of interaction with metal ions [28-29]. Because of the wide diversity of coordination possibilities there are often controversies as to the mode of coordination even in simple complexes with metal ions. Some authors claim that only nitrogen atoms of the nucleotide are effectively engaged in the metallation [30-43], while others maintain that it requires a combined engagement of nitrogen atoms and phosphate group [44-71]. There are also researchers who point to the involvement of only phosphate group of the nucleotide in the metallation [72-77]. The reaction of nucleotides with tetramines results in the formation of molecular complexes (Fig. 3) [78-88]. In the literature to date, there is no agreement as to the character of interactions and effectiveness of nucleotide donor groups in the formation of adducts with polyamines [80-82, 85-87, 89, 90]. According to some authors, the interaction between a nucleotide and polyamines in the metal-free systems has a noncovalent ion-ion or ion-dipole nature and the stability of molecular complexes is determined by the number of active centres in the reagents and the structural factor [80-84, 87]. According to other authors, it is a typical electrostatic interaction and the adduct stability is determined by the charge of the reagents [85, 89]. In the adducts formed by nucleotides with polyamines, the main interaction centres of a nucleotide are endocyclic nitrogen atoms and a phosphate group (the latter undergoes deprotonation already at a low pH), while in the case of tetramine the interaction centres are the NHx+ groups [77, 80-87, 89-91]. In the ternary systems of metal/nucleotide/tetramine, the following heteroligand molecular complexes are formed: MLźźźźźźHxL' (x = 4, HxL'-fully protonated polyamine) (Fig. 4) [80-82, 91, 94, 96], mixed protonated complexes MLHxL' (x = 1, 2, 3) (Fig. 5) [81, 82, 92, 96] and MLL' type complexes (Fig. 6) [81, 82, 91]. A significant influence of polyamines on the character of interactions of nucleotides with metal ions has been noted [80-82, 90-96]. In molecular complexes, the fully protonated polyamine is located in the outer coordination sphere. In the MLHxL' type complexes, the deprotonated nitrogen atoms of tetramine are involved in the coordination, while its protonated centres -NHx+ take part in noncovalent interactions that additionally stabilise the complex [81, 82, 92, 96, 97]. In the MLL' type complexes, oxygen atoms of nucleotide phosphate group and deprotonated nitrogen atoms of tetramine are in the inner coordination sphere, while nucleotide donor nitrogen atoms do not take part in the metallation [81, 82, 91].