Wyniki wyszukiwania - BazTech

1

Białka błony zewnętrznej fusobacterium nucleatum jako potencjalny czynnik promocji nowotworu jelita grubego

Lesiów M. K., Krupa K., Komarnicka U. K., Walencik P. K.

Wiadomości Chemiczne

|

2018

|

[Z] 72, 7-8

585--596

EN

Fusobacterium nucleatum is a Gram-negative, anaerobic bacterium located in an oral cavity. This bacterium can migrate with blood to the different part of the human body e.g colon. The studies suggest participation of Fn in a colorectal cancer promotion, but a particular mechanism of this disease is still unclear. Colorectal cancer leads to million of new death cases each year. It is third in the worldwide in terms of mortality. The predictions for the coming years are not optimistic. The statistics encourage researchers to know the details of the mechanism of colorectal cancer. It is suggest, that outer membrane proteins of Fn are responsible for development of this disease. Transition metal ions such as Cu(I), Cu(II), Fe(II) can coordinate to proteins and generate free radicals by Fenton reaction. Reactive oxygen species (ROS) destroy important biological macromolecules such as DNA, proteins or lipids and cause different diseases. The paper presents characteristics of Fn and its outer membrane proteins, description of copper(II) complexes and their ability to ROS generation.

2

Styrene oxidation by copper(II) complexes salen-type encapsulated into NaY zeolite

Kuźniarska-Biernacka I., Carvalho M. A., Correia Neves I., Fonseca A. M., Lisińska-Czekaj A., Czekaj D.

Archives of Metallurgy and Materials

|

2013

|

Vol. 58, iss. 4

1291--1294

EN

The copper(II) complex with a Schiff-base salen-type ligand has been encapsulated in the nanopores of a NaY zeolite by using two different methodologies, the flexible ligand and in situ complex preparation methods. The encapsulated and non-encapsulated copper(II) complexes were screened as catalysts for styrene oxidation by using TBHP as the oxygen source in acetonitrile solvent. Under the optimized conditions, the catalysts exhibited moderate activity with higher selectivity to benzaldehyde. Both heterogeneous catalysts were found to be reusable after the catalytic cycle, but with some loss of activity.

PL

Osadzenie kompleksu miedzi(II) z zasadą Schiffa typu salen na zeolicie typu NaY zostało przepowadzone za pomocą dwóch metod „flexible ligand" i „in situ”. Katalityczne właściwości otrzymanego kompleksu oraz jego heterogenizowanych analogów badano w reakcji utleniania styrenu w obecności TBHP. Jako rozpuszczalnik stosowano acetonitryl. Testowane katalizatory wykazują średnią aktywność katalityczną z tendencją wytwarzania aldehy du benzoesowego. Oba heterogenizowane katalizatory mogą być wykorzystywane ponownie bez utraty aktywności katalitycznych.

3

Magnetyczne oddziaływania nadwymienne przez wiązania wodorowe

Korabik M.

Wiadomości Chemiczne

|

2008

|

[Z] 62, 5-6

449-478

EN

Hydrogen bonds play a key role in interactions in biological structures, supramolecular chemistry, and crystal engineering [28, 29]. The development of supramolecular structure created by hydrogen bonds is a new challenge for the synthesis of materials, in order to study their magnetic behaviour [59, 62]. A role played by hydrogen bonds in the transmission of magnetic interactions is still not fully understood, but the number of magnetically coupled hydrogen-bonded systems is growing. The present paper describes magnetic properties of copper(II) complexes [33] with nitrobenzoate and salicylate ligands where the system of hydrogen bonds O-HźźźO is the only path of magnetic interaction. Magnetic measurements in the temperature range 1.8-300 K show magnetic phase-transition at 6 K to antiferromagnetically coupled CuII dimers with singlet-tryplet energy gap 2J = -6.26 cm-1. A variety of different supramolecular hydrogen bond structures [27, 33-52, 57-62] and significant changes in their magnetic properties were analyzed to show the role of hydrogen bonds in magnetic interactions. Magnetostructural correlation has been made taking into account both covalently bridging ligand and the existence of intermolecular hydrogen bonds. An evidence for hydrogen-bond-mediated exchange coupling has been observed in magnetic study as well as in DFT calculations [40, 48]. Intermolecular interaction has been generally treated as a nuance, but today, it has established itself as an important functional tool, tunable at will [59] in the design of nanosized magnetic materials and their dimensionally-expanded compounds [57-62]. Intermolecular magnetic exchange interactions through hydrogen bonds, can have a large influence on the quantum properties of single molecular magnets SMMs [59]. Hydrogen bonding leads to coupling of the magnetic effects of individual SMMs units and to different quantum behaviour. Even very weak hydrogen bond inter-molecular interactions demonstrate a possibility of switching from an original nanosized magnetic system to a correlated system, for example, from single molecule magnet SMM to single chain magnet SCM or from such nanosized magnets to a bulk magnet [59].