共 44 条
Landscape of the structure-O-H bond dissociation energy relationship of oximes and hydroxylamines
被引:17
作者:
Dao, Rina
[1
]
Wang, Xinyu
[1
]
Chen, Kexian
[2
]
Zhao, Chenxuan
[1
]
Yao, Jia
[1
]
Li, Haoran
[1
,3
]
机构:
[1] Zhejiang Univ, Dept Chem, ZJU NHU United R&D Ctr, Hangzhou 310027, Zhejiang, Peoples R China
[2] Zhejiang Gongshang Univ, Sch Food Sci & Biotechnol, Hangzhou 310018, Zhejiang, Peoples R China
[3] Zhejiang Univ, Coll Chem & Biol Engn, State Key Lab Chem Engn, Hangzhou 310027, Zhejiang, Peoples R China
基金:
中国国家自然科学基金;
关键词:
HYPERFINE COUPLING-CONSTANTS;
MOLECULAR-OXYGEN;
N-HYDROXYPHTHALIMIDES;
AEROBIC OXIDATION;
GAS-PHASE;
RADICALS;
HYDROXYIMIDES;
AUTOXIDATION;
EQUILIBRIUM;
ENTHALPIES;
D O I:
10.1039/c7cp03809g
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
The relationship between the homolytic O-H bond dissociation enthalpies (BDEs) and the structures of N-oxyl radical precursors (i.e. hydroxylamines and oximes) is important to predict their reactivity. Yet several crucial facts remain hidden to complete the picture such as the substituent electronic effects on the BDEs of oximes. In this work, the O-H BDEs of 120 hydroxylamines and 120 oximes have been calculated. It was found that the majority of the iminoxyl radicals are sigma radicals, except for some pi radicals. The resonance effect dominates the electronic effects on the BDEs of oximes, and electron-donating conjugation increases the BDE. However, both the resonance and the inductive effects are important in the BDEs of hydroxylamines; meanwhile, the BDEs increase with the increase of the electron-withdrawing ability of the substituents. Besides, the Delta BDEs of oximes and hydroxylamines with two substituents almost equal the algebraic sum of the Delta BDEs of single substituents. In addition, dipole-dipole repulsion is responsible for the difference in the BDEs of open chain and cyclic acyl hydroxylamines. Although the ring strain affects the N-O bonding property of nitroxide radicals, it has negligible effect on the BDEs of oximes. These new rules provide a complete and precise understanding of the structure-bond energy relationship of N-oxyl radical precursors.
引用
收藏
页码:22309 / 22320
页数:12
相关论文