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Formation of a new hybrid complex via coordination interaction between 5,10,15-tritolyl-20-(4- and 3-pyridyl)porphyrin or 5,10,15-triphenyl-20-(4-pyridyl)porphyrin and the α-[MSiW 11O 39] 6− Keggin-type polyoxometalate (M = Co 2+ and Ni 2+)
Evidence for the formation of a new complex based on the association of 5,10,15-tritolyl-20-(4- and 3-pyridyl)porphyrin or 5,10,15-triphenyl-20-(4-pyridyl)porphyrin and α-[MSiW 11O 39] 6− (M = Co 2+ and Ni 2+) Keggin-type polyoxometalate is given by steady-state and time-resolved luminescence and pa...
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Published in: | Inorganica Chimica Acta 2010-06, Vol.363 (10), p.2185-2192 |
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Main Authors: | , , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Evidence for the formation of a new complex based on the association of 5,10,15-tritolyl-20-(4- and 3-pyridyl)porphyrin or 5,10,15-triphenyl-20-(4-pyridyl)porphyrin and α-[MSiW
11O
39]
6− (M
=
Co
2+ and Ni
2+) Keggin-type polyoxometalate is given by steady-state and time-resolved luminescence and paramagnetic
1H NMR.
New complexes based on a coordination interaction between a pyridyl-porphyrin (namely 5,10,15-tritolyl-20-(4-pyridyl)porphyrin, 5,10,15-tritolyl-20-(3-pyridyl)porphyrin or 5,10,15-triphenyl-20-(4-pyridyl)porphyrin) and a Keggin-type polyoxometalate (α-[MSiW
11O
39]
6−, M
=
Co
2+ or Ni
2+) are formed in solution. The formation of these complexes is clearly evidenced by steady-state and time-resolved luminescence measurements. A strong quenching of the porphyrin fluorescence, accompanied by an important shortening of the fluorescence lifetime, is observed upon addition of the POM and formation of the complexes. Using a variant of the Job’s method from the luminescence spectra, the association constants of the complexes have been estimated to be around 10
6
L
mol
−1. Paramagnetic
1H NMR experiments confirm the formation of the complexes. Indeed, in addition to broadenings of the signals, the coordination binding of the POM to the porphyrin induces large high-frequency shifts for the protons of the pyridyl group coordinated to the
paramagnetic metal, and low-frequency shifts for all the other resonances. |
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ISSN: | 0020-1693 1873-3255 |
DOI: | 10.1016/j.ica.2010.03.015 |