XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
138
T1: P–5
Spectroscopic study of metalloporphyrins with out-of-plane ligands
Aleksander Gorski
1
, Alexander Starukhin
2
, Jędrzej Solarski
1
, Tat’iana Pavich
2
,
Valerii Kniukshto
2
, Victor Chernii
3
, and Iryna Tretyakova
3
1
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw,
Poland, e-mail: agorski@ichf.edu.pl
2
B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Independence Av. 68,
220072, Minsk, Belarus
3
V.I.Vernadskii Institute of General and Inorganic Chemistry National Academy of Sciences of
Ukraine, Palladin Av. 32/34, 03680, Kyiv, Ukraine
Photophysical parameters of metallocomplexes of macrocyclic compounds depend on the
molecular structure of organic ligands and nature of central ions. Previously, we proposed a ligand
exchange reaction at the central metal atom of a phthalocyanine (Pc) macrocycle which induces
changes of physical and chemical properties of parent compound [1]. This report is devoted to the
study of porphyrins with out-of-plane ligands which are structural analogues of Pc. Porphyrins with
out-of-plane coordinated ligands possess rare electrochromic properties and stay an object of primary
interest of the relationship between the molecular structure and photophysical properties.
In this report we presented spectroscopic and photophysical data obtained for new
metalloporphyrins with out-of-plane ligands: dichlorido zirconium 2,3,7,8,12,13,17,18-
octamethylporphyrin
(OMPZrCl
2
)
and
dibenzoylmethanato
zirconium
5,10,15,20-
tetraphenylporphyrin (TPPZrDbm
2
) at ambient and liquid nitrogen temperatures. The structures of
OMPZrCl
2
and TPPZrDbm
2
are presented on Fig.1 (a, b). OMPZrCl
2
was obtained by the
metallization reaction of OMPН
2
with Zirconium tetrachloride, аnd TPPZrDbm
2
by ligand exchange
reaction of TPPZrCl
2
with dibenzoylmethane, as was previously reported for Pc complexes of Zr and
Hf [2].
a)
b)
c)
Fig. 1. Structures of OMPZrCl2 (a) and TPPZrDbm2 (b). TPPZrDbm2 fluorescence
and phosphorescence spectra (c) in 2-methyltetrahydrofurane at 77 K (λexc.=422 nm).
The exchange of central ion from Zn(II) to Zr(IV) atom leads to noticeable modification of spectral
and photophysical properties of the metallocomplexes. In particular, very intensive phosphorescence
is appeared in the spectral range about 700 nm at low temperatures (Fig. 1c). In contrast, the
fluorescence of new complexes at ambient temperature is significantly quenched. The fluorescence
lifetimes measured in 2-methyltetrahydrofurane at ambient temperature are 0.22 ns and 0.57 ns for
OMPZrCl
2
and TPPZrDbm
2
, respectively.
Keywords: metalloporphyrins; out-of-plane ligands; luminescence spectra
Acknowledgment
This work was supported by the European Union’s Horizon 2020 research and innovation program under grant
agreement No 645628.
References
[1] L.A. Tomachynski, I.N. Tretyakova, V.Ya. Chernii, S.V. Volkov et all, Inorg. Chim. Acta, 361 (2008) 2569.
[2] V.Ya.
Chernii,
V.V.
Bon,
I.N.
Tretyakova,
O.V.
Severinovskaya,
S.V.
Volkov,
Dyes
and
Pigm.
94
(2012)
187.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
139
T1: P–6
Kinetics consideration on triplet-triplet annihilation process
for photochemical up-conversion
Jędrzej Solarski
1
, Alexander Gorski
1
, Jakub Ostapko
1
, and Viktor Chernii
2
1
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw,
Poland, e-mail: jsolarski@ichf.edu.pl
2
V.I.Vernadskii Institute of General and Inorganic Chemistry National Academy of Sciences of
Ukraine, Palladin Av. 32/34, 03680, Kyiv, Ukraine
The process of organic photon upconversion (UC) through triplet-triplet annihilation (TTA),
is one of several technologies that can, in principle, convert low-energy photons to high-energy.
One way to achieve this type of photon upconversion (UC) is through the process called Triplet-
Triplet Annihilation (TTA) relying on the interaction between two molecules; a sensitizer and an
annihilator. The efficiency of energy up-conversion (UC) via triplet-triplet annihilation (TTA) is
limited by two steps of the overall process [1]: the triplet-triplet energy transfer between a
phosphorescent donor and an emitting acceptor (annihilator), and the triplet-triplet annihilation
of acceptors. The latter generates the acceptor singlet excited state from which emission light
higher in energy than that of excitation takes place (thence the UC). Both steps are considered to
be energy transfer processes of Dexter type (electron exchange). Despite its relevance, a general
understanding of bimolecular energy transfer reactions in liquid media is still lacking [2, 3]. This
is especially true about the proper kinetic description in terms of the reactants and medium
properties. This is due to the scarcity of experimental data due to the specific requirements
needed to be fulfilled by the studied physico-chemical model systems that would enable to
reveal relevant kinetic information with high precision. Herein we present a new method to
measure the time profile of excited triplet state of the acceptor in the model systems. The time
profile triplet excited state of the annihilator is crucial in establishing proper kinetic scheme for
this reaction. A proper kinetical description and the description of the factors that control energy
transfer reactions would potentially lead to maximizing the UC efficiency by controlling the
magnitude of TTA rate constants.
Keywords: upconversion; delayed fluorescence; triplet-triplet annihilation
Acknowledgment
This work was supported by the European Union’s Horizon 2020 research and innovation program under
grant agreement No 645628.
References
[1] T.N. Singh-Rachford, F.N. Castellano, Coordination Chemistry Rev. 254 (2010) 2560.
[2] K. Sandros, Acta Chem. Scand. 18 (1964) 2355.
[3] V. Balzani, F. Bolletta, F. Scandola, J. Am. Chem. Soc. 102 (1980) 2152.
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