4th EucheMs chemistry congress

Poster Session 1
s944
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - inorganic Chemistry
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KinetiC StudieS of Ln(iii) CoMPLexeS
of dotP-LiKe MACroCyCLiC LiGAndS
r. SevCiK 1 , J. vAneK 2 , P. LuBAL 2 , z. KotKovA 3 ,
J. KoteK 3 , P. herMAnn 3
1 Masaryk University Faculty of Science, Department of
Chemistry, Brno, Czech Republic
2 Masaryk University Faculty of Science, Department of
Chemistry/CEITEC, Brno, Czech Republic
3 Charles University, Department of Inorganic Chemistry,
Prague, Czech Republic
The Ln(III) complexes of macrocyclic ligands (mostly
DOTA/DOTP derivatives) are often employed in medicinal
chemistry as MRI agents and luminescent probes. For any
biomedical applications, these metal complexes should exhibit a
high thermodynamic stability as well as kinetic inertness under
physiological conditions and therefore, knowledge of their
thermodynamic/kinetic properties (e.g. dissociation rate constants
for an estimation of kinetic inertness) is important to evaluate their
use in these applications.
In this work, the formation/acid-assisted dissociation
kinetics of chosen Ln(III) (Ln = Ce, Eu) complexes with
DOTP-like macrocyclic ligands (H dotp = 1, 4, 7, 10 – tetraaza -
8
cyclododecane – 1, 4, 7, 10 – tetrakis(methylphospho nic acid)
and their analogs: H dotp 4 OEt = tetrakis(monoethylester),
H dotp 4 H = tetrakis(methylphosphinate), H dotp 4 Ph =tetrakis[methyl
(phenyl)phosphinate) was studied using molecular absorption
spectroscopy in UV region and time-resolved laser-induced
fluorescence spectroscopy (TRLIFS). The impact of the
coordination number of Ln(III) ion (Ce vs. Eu) and the
softness/hardness of pendant arms of studied macrocyclic ligands
on kinetic properties of Ln(III) complexes was investigated in
order to optimize the structural design for synthesis of bifunctional
chelators for potential medical applications.
Acknowledgements: This work was done in the framework of
EU CM1006 program. We thank to Ministry of Education of the
Czech Republic (grants ME09065, MSM0021620857, CEITEC
CZ.1.05/1.1.0/02.0068) for financial support.
Keywords: Macrocycles; Lanthanides; Kinetics;
4 th EucheMs chemistry congress
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PhotoCAtALytiC wAter reduCtion with
rutheniuM PoLyPyridyL ChroMoPhoreS
r. StAehLe 1 , M. fiLiPoviC 2 , S. LoSSe 3 , J. G. voS 4 ,
i. ivAnoviC-BurMAzoviC 2 , S. rAu 1
1 Inorganic Chemistry I, Materials and Catalysis, Ulm,
Germany
2 Bioinorganic Chemistry, Chemistry and Pharmacy, Erlangen,
Germany
3 Leibniz Institute for Catalysis, Applied Homogeneous
Catalysis, Rostock, Germany
4 Inorganic Chemistry, School of Chemical Sciences, Dublin,
Ireland
The splitting of water by solar energy, using ruthenium
polypyridyl complexes can be divided into two half reactions; (i)
water oxidation, to yield O and (ii) water reduction, producing
2
H , an alternative fuel. Systems for both separated reactions are
2
well-known using a multiplicity of different dyes and sacrificial
redox reagents. For the light driven overall water splitting both
reactions must have the ability to work parallel, i.e. H evolution
2
in the presence of O . This could not be obtained till now.
2
A supramolecular photocatalytic system for the water reduction
consisting of a ruthenium complex with a 4,4'-dicyano-2,2'-
-bipyridine ligand as photosensitizer has been studied.
Surprisingly this system shows a superior catalytic activity
under aerobic than under anaerobic conditions. The mechanism
of this reaction was studied in detail whereby a conversion of the
nitrile groups and efficient photocatalytic consumption of O2 could be observed. Based on these results we synthesized and
characterized the related ruthenium complex with a 4,7-dicyano-
-1,10-phenanthroline and a 4-cyano-1,10-phenanthroline ligand
for comparison.
references:
1. S. Losse, H. Görls, R. Groarke, J.G. Vos, S. Rau,
Eur. J. Inorg.Chem. 2008, 28, 4448-4452.
2. S. Losse, J.G. Vos, S. Rau, Coord. Chem. Rev. 2010, 254,
2492-2504.
Keywords: Ruthenium; Water splitting; Homogeneous
catalysis; Cobalt;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc