Kompleksy jonów metali d- i f-elektronowych z N-tlenkiem pirydyny i związkami pochodnymi : badania spektroskopowe
Journal Title: Wiadomości Chemiczne - Year 2011, Vol 65, Issue 5
Abstract
This article reviews results of studies, collected in the literature, related to complexation abilities of pyridine N-oxides, including forms and properties of dand f-metal ion complexes with this group of ligands. In this paper the synthetic pathways of the ligands, based on an oxidation of the corresponding heterocyclic compounds are presented (Scheme 3) [2, 4, 5]. Substituted pyridine N-oxides form an interesting group of compounds, which have found numerous applications [296-299, 314-318]. They have been used in catalysis, crystal engineering, synthesis of coordination polymers, as well as drugs and components in pharmaceutical chemistry [300-309]. Some of them are useful in destroying of microorganisms and the HIV virus [277, 278, 303-307]. Moreover, they are important compounds in the thermal and photochemical oxidation processes [296-299]. The complexes of metal ions with the N-oxide ligands can be formed by binding an oxygen atom of the N›O group, and/or by binding the substituents present in the aromatic ring, e.g. oxygen atoms of carboxylic groups. The complexes can be obtained in monomeric [64, 159], dimeric [58] or polymeric forms [60, 153, 175]. The formation of polymeric forms is more effective when the distance between the positions of COOH and N›O groups in the aromatic ring increases [168]. Complexes of Ln3+ ions and particularly of Eu3+ with pyridine N-oxides are good luminescent materials, better than their heterocyclic counterparts [180, 211]. The emission intensity of europium ions in these systems depends on the efficiency of the LMCT (ligand-metal charge transfer) and LMET (ligand-metal energy transfer) transitions, as well as on electron-donor properties of the substituents present in the pyridine N-oxide ring [37, 132, 155]. A special role in the complexation of Ln3+ ions plays cryptands, which can encapsulate the metal ion. This process protects the metal ion from a penetration of its first coordination sphere by solvent molecules or counterions [245, 246]. The complexes of europium(III) with macromonocyclic, macrobicyclic and acyclic ligands, equipped with photoactive units such as pyridine N-oxide, 2,2'-bipyridine-N,N'-dioxide or 3,3'-biisoquinoline-2,2'-dioxide in solutions, solid states, and incorporated in a silicate matrices by sol-gel method, gained a lot of attention [247-274].
Authors and Affiliations
Zbigniew Hnatejko
Keywords
Related Articles
- EP ID EP591227
- DOI -
- Views 123
- Downloads 0
Wzór Scherrera : stulecie błędnych praktyk
We present the sources of uncertainty in the evaluation of grain size in nanomaterial. The calculations are made for the same diffraction pattern using Scherrer and Williamson-Hall methods. As an example we use the CoCr2...
Badania nanokompozytów hydroksyapatytowych wobec bakterii beztlenowych
Nanocrystalline apatites Ca10(PO4)6(OH)2(HAp) non-doped and doped with Ag+and Eu3+ions were synthesized by different wet chemistry methods. The obtained hydroxyapatite was loaded with Ag0, as well as nitroimidazole antim...
Znaczenie i przykłady zastosowania banków pseudoatomów asferycznych w krystalografii małych cząsteczek i ich potencjalne wykorzystanie w krystalografii makromolekuł
X-rays are diffracted by the electron density of crystals. Thus, the correct analysis of a single crystal X-ray diffraction pattern can provide information about the distribution of the electron density. How precise and...
Chemiczne aspekty celowanej terapii przeciwnowotworowej II. Połączenia nośnik -lek
Traditional anticancer therapy is usually low effective. Popular and common drugs applied in anticancer therapy are characterized by low solubility and nonspecific biodistribution in an organism. The chemotherapy kills n...
Zastosowanie soli chinoliniowych i pirydyniowych do oznaczania wybranych związków siarki w próbkach biologicznych
heterocyclic ring [4, 13, 23]. In analytical chemistry quinolinium and pyridinium salts such as 2-chloro-1-methylquinolinium tetrafluoroborate (CMQT) or 1-benzyl-2-chloropyridinium bromide (BCPB) perform very well as thi...