Abstract:
The ability of oxyamines to undergo homolytic cleavage of the O-C bond, leading to the formation of stable radicals, is widely used in polymerization processes and to prevent oxidative stress in materials. We present a mid and near-infrared spectroscopy study on two model compounds, the commercial N,N-diethylhydroxyloxyamine (C4H11NO) and the non-commercial N,N-diethylacetyloxyamine (C6H13NO2) in the liquid phase. The analysis of the spectra is based on a complete exploration of the conformational space, coupled to harmonic and anharmonic calculations performed using the generalized second-order vibrational perturbation theory (GVPT2) formalism at the B3LYP-D3(BJ)/Def2-TZVP level of calculation and potential energy distribution analysis. In the most stable species out of 25, the three amine chains present an all-anti arrangement, with the carbonyl oxygen atom pointing towards the nitrogen lone pair. The simulated spectra are in overall good agreement with the experimental ones, and suitable for the assignment of the main observed bands. Furthermore, similarities and divergences between the two molecules are discussed.
摘要:
氧胺经历O-C键的均裂的能力,导致形成稳定的自由基,广泛用于聚合过程和防止材料中的氧化应激。我们对两种模型化合物进行了中近红外光谱研究,商业N,N-二乙基羟基氧胺(C4H11NO)和非商业N,液相中的N-二乙基乙酰氧基胺(C6H13NO2)。对光谱的分析是基于对构象空间的全面探索,耦合到在B3LYP-D3(BJ)/Def2-TZVP计算和势能分布分析水平上使用广义二阶振动扰动理论(GVPT2)形式主义进行的谐波和非谐波计算。在25个中最稳定的物种中,三个胺链呈现全反排列,羰基氧原子指向氮孤对子。模拟光谱与实验光谱总体吻合良好,并适用于主要观察波段的分配。此外,讨论了两种分子之间的异同。