Matrix isolation infrared spectroscopic study of 4-Pyridinecarboxaldehyde and of its UV-induced photochemistry
| Autor: | Liesel Cluyts, Archna Sharma, Rui Fausto, Kristien Schoone, Nihal Kuş |
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| Přispěvatelé: | Anadolu Üniversitesi, Fen Fakültesi, Fizik Bölümü, Kuş, Nihal |
| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Infrared 4-Pyridinecarboxaldehyde Matrix isolation Infrared spectroscopy Quantum Chemical Calculations 010402 general chemistry Photochemistry 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Analytical Chemistry Narrowband Uv-Induced Photochemistry Benzaldehyde Matrix Isolation Infrared Spectroscopy chemistry.chemical_compound Delocalized electron chemistry Pyridine Molecule Density functional theory Instrumentation Spectroscopy |
| Zdroj: | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 171:207-212 |
| ISSN: | 1386-1425 |
| DOI: | 10.1016/j.saa.2016.08.002 |
| Popis: | WOS: 000385601300027 PubMed ID: 27532226 The structure, infrared spectrum, barrier to internal rotation, and photochemistry of 4-pyridinecarboxaldehyde (4PCA) were studied by low-temperature (10 K) matrix isolation infrared spectroscopy and quantum chemical calculations undertaken at both Moller-Plesset to second order (MP2) and density functional theory (DFT/B3LYP) levels of approximation. The molecule has a planar structure (Cs point group), with MP2/6-311 ++G(d,p) predicted internal rotation barrier of 26.6 kJ mol(-1), which is slightly smaller than that of benzaldehyde (similar to 30 kJ mol(-1)), thus indicating a less important electron charge delocalization from the aromatic ring to the aldehyde moiety in 4PCA than in benzaldehyde. A complete assignment of the infrared spectrum of 4PCA isolated in an argon matrix has been done for the whole 4000-400 cm(-1) spectral range, improving over previously reported data. Both the geometric parameters and vibrational frequencies of the aldehyde group reveal the relevance in this molecule of the electronic charge back-donation effect from the oxygen trans lone electron pair to the aldehyde C-H anti-bonding orbital. Upon in situ UV irradiation of the matrix-isolated compound, prompt decarbonylation was observed, leading to formation of pyridine Portuguese "Fundacao para a Ciencia e a Tecnologia" (FCT) - COMPETE-UE [UI0313/QUI/2013]; FCT [SFRH/BPD/88372/2012] The Coimbra Chemistry Centre (CQC) is supported by the Portuguese "Fundacao para a Ciencia e a Tecnologia" (FCT), through the project UI0313/QUI/2013, co-funded by COMPETE-UE. N. Kus thanks FCT for the post-doctoral grant ref. SFRH/BPD/88372/2012. |
| Databáze: | OpenAIRE |
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