Experimental and DFT studies on the vibrational, electronic spectra and NBO analysis of thiamethoxam.
Vibrational and electronic spectral measurements were performed for 3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro) amine (thiamethoxam). Optimized geometrical structure and harmonic vibrational frequencies were calculated with ab initio RHF and DFT (B3LYP, CAMB3LYP, M06 and PBE1PBE) methods with 6-311++G (d, p) basis set. Complete assignments of the observed spectra were proposed. The absorption spectra of the compound were computed in gas-phase using TD-B3LYP/6-311++G (d, p) approach and H2O solution using PCM-TD-B3LYP/6-311++G (d, p) approach. The calculated results matched well with the experimental values. Temperature dependence of thermodynamic parameters in the range of 100-1000 K were determined. The bond orbital occupancies, contribution from parent natural bond orbital (NBO), the natural atomic hybrids was discussed.
School of Chemical Engineering, Ningxia University, Ningxia 210094, PR China.
Fang
F
Zhang
Yu
Y
Zhang
Haiwei
H
Ni
Kuirong
K
Ma
Rongqing
R
Li
D004583:Electrons; D008958:Models, Molecular; D008968:Molecular Conformation; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000737:chemistry*; D010078:Oxazines / Q000737:chemistry*; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013816:Thermodynamics; D000077922:Thiamethoxam; D013844:Thiazoles / Q000737:chemistry*; D014732:Vibration
D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D013844:Thiazoles; D000077922:Thiamethoxam
Density functional theory (DFT); Electronic spectra; NBO; Thiamethoxam; Vibrational spectra