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Structural and electronic effects involving pyridine rings in 4-methylpyridine Cu4OX6L4 complexes. I. Vibrational spectra of Cu4OBr n Cl(6− n )(4-Mepy)4 complex
Ondrejovič, Gregor, Koman, Marian and Kotočová, Adela Structural and electronic effects involving pyridine rings in 4-methylpyridine Cu4OX6L4 complexes. I. Vibrational spectra of Cu4OBr n Cl(6− n )(4-Mepy)4 complex Chemical Papers, Vol.62, No. 5, 2008, 480-486
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Document type:
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Článok z časopisu / Journal Article |
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Collection:
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Chemical papers
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| Author(s) |
Ondrejovič, Gregor
Koman, Marian
Kotočová, Adela
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| Title |
Structural and electronic effects involving pyridine rings in 4-methylpyridine Cu4OX6L4 complexes. I. Vibrational spectra of Cu4OBr n Cl(6− n )(4-Mepy)4 complex
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| Journal name |
Chemical Papers
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| Publication date |
2008
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| Year available |
2008
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| Volume number |
62
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| Issue number |
5
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| ISSN |
0366-6352
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| Start page |
480
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| End page |
486
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| Place of publication |
Poland
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| Publisher |
Versita
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| Collection year |
2008
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| Language |
english
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| Subject |
250000 Chemical Sciences
250200 Inorganic Chemistry
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| Abstract/Summary |
Gaussian analysis of bands between 500 cm−1 and 600 cm−1 attributed to the ~u as (Cu4O) stretching vibration of the tetrahedral Cu4O core in Cu4OBr n Cl(6−n)(4-Mepy)4 (n = 0–6) complexes showed two bands, symmetry reduction of the T 2 mode of vibration towards the A 1 and E modes and vibrational coupling with an R-sensitive in-plane pyridine ring bending. The Cu-O bond is considered as vibrationally coupled with the Cu-N bond and the pyridine ring through the donor-acceptor vibrational coupling and the corresponding equilibrium charge distribution. The linear correlation between ~u as (Cu4O) and the number of bromides in Cu4OBr n Cl(6−n)(4-Mepy)4 complexes was used for the estimation of partial charges on the 4-Mepy ligands which were positive for the prevailing donors and negative for the prevailing acceptors thus evoking a π-back bonding between the Cu(II) atoms and the 4-Mepy ligands. Correlations involving selected bond lengths and bond angles in the molecular structure of the Cu4OCl6(4-Mepy)4 complex with four symmetrically independent molecules present in the unit cell indicate a symmetry reduction of the T 2 mode of vibration and the π-back bonding between the Cu(II) atoms and the 4-Mepy ligands.
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