Experimental and theoretical vibrational study of the fungicide pyraclostrobin.
Spectrochim Acta A Mol Biomol Spectrosc
; 259: 119888, 2021 Oct 05.
Article
em En
| MEDLINE
| ID: mdl-34015601
The vibrational study of the pyraclostrobin (methyl N-(2-{[1-(4-chlorophenyl)-1H-pyrazol-3-yl]oxymethyl}phenyl) N-methoxycarbamate) molecule, a synthetic fungicide for agricultural uses, was performed. Pyraclostrobin belongs to the strobilurin family and acts by inhibiting the fungus respiratory chain at the level of Complex III, becoming an excellent agent for preventive, curative and eradicative activities against a wide range of fungal plant pathogens. However, its presence needs to be monitored to avoid the excessive and/or improper use that may compromise human or environmental health. The FTIR and Raman spectra of pyraclostrobin in pure solid state were recorded and compared with those obtained from both the substance in CH2Cl2 solution and in an agricultural commercial product (Comet® BASF). The spectral analysis was complemented with quantum-chemical calculations at the DFT level (B3LYP/6-311G*) for the predictions of the molecular geometry and its vibrational behavior. The high flexibility of the molecule was explored by performing potential energy scans on several dihedral angles and the results suggested that the main conformer of pyraclostrobin is that possessing the ortho-substituted benzene ring in perpendicular orientation regarding the plane that contains the ether group and the pyrazole ring, although the presence of a second preferred conformation in the experimental vibrational spectra was not ruled out. Among the many vibrational bands of pyraclostrobin that were well identified in the spectrum of the composite product for agricultural use, the one located at 936 cm-1 stood out. This signal was assigned to a vibration of the pyrazole ring and promised to be a good candidate as marker of the presence of the fungicide in complex matrixes.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vibração
/
Fungicidas Industriais
Limite:
Humans
Idioma:
En
Revista:
Spectrochim Acta A Mol Biomol Spectrosc
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Reino Unido