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Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
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氧化物中的O-H键解离:恢复了秩序
Derek A Pratt1, Jessie A Blake, Peter Mulder
1Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. dpratt@uiuc.edu
Journal of the American Chemical Society
|August 26, 2004
概括
这项研究报告了13个氧化物O-H键解离度 (BDE). 立体效应,而不是电子移位,解释了oxime BDEs的差异,证实了先前的发现.
科学领域:
- 物理有机化学 有机化学
- 计算化学计算化学
- 频谱学是一种光谱学.
背景情况:
- 氧化物 (RR'C=NOH) 是有机化合物,具有不同的R和R'组 (H,基,基).
- 之前的研究提出了电子转移到芳香环或特定的基因结构的影响氧化物O-H键解离度 (BDE).
- 关于影响氧化物O-HBDE的因素的不一致发现需要进一步调查.
研究的目的:
- 准确确定一系列13种不同的氧化物O-H键解离度 (BDE).
- 通过实验验证使用已确定的点对氧化物BDE的理论计算.
- 澄清硬质效应与电子移位在影响氧化物OHBDE中的作用.
主要方法:
- 使用热化学数据和电子偏磁共振 (EPR) 谱法对特定氧化物进行O-H BDEs的实验性确定.
- 在高温下 (423-443 K) 测量相关氧化乙烯的热分解速率.
- 对BDE的理论计算,根据实验点和修订的热化学数据进行验证.
主要成果:
- 报告了13个氧基的OH-BDE,其值经过调整以考虑修订的形成热量和结合.
- 实验数据证实,体效应,而不是电子移位,是氧化物O-H BDEs观察到差异的主要驱动因素.
- 该研究驳斥了由于异地化而导致芳香氧化物中BDE显著降低的说法,并质疑了阻碍基的垂直结构.
结论:
- 简单的固体效应足够地解释了不同替代剂中氧化物O-HBDE的相对较小的变化.
- 这些发现再次证实了1973年的结论,即硬质因素在电子移位或几何变化上占主导地位.
- 这项研究更清楚地了解了控制氧化物中OH键稳定性的因素.
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