Substituted hydrocarbon: a CCSD(T) and local vibrational mode investigation
Substituted hydrocarbon: a CCSD(T) and local vibrational mode investigation
复制标题
DOI：
10.1080/00268976.2021.1970844
复制
发表时间：
2021-08-27
影响因子：
1.7
通讯作者：
Kraka, Elfi
中科院分区：
文献类型：
--
作者：
Ann Delgado, Alexis Antoinette;Sethio, Daniel;Kraka, Elfi
在过去的七十年里，碳氢化合物的碳-碳键上的取代基效应一直是人们感兴趣的话题，因为所得的信息将使人们能够调节CC键的活性。然而，目前对乙炔、乙烯和乙烷及其衍生物的C当量、C=C和C-C键强度的评估依赖于间接测量，如键长和键离解焓。在这项工作中，我们介绍了一个定量测量的固有强度的C相当于C，C=C，和C-C键的一组40烃系统组成的3个母体结构，36烃衍生物涉及CF 3，CH 3，CHO，F，NH 2，或OH基团，和共轭体系，基于振动光谱。对于系统1-32和34-40，在CCSD（T）/cc-pVTZ理论水平下计算局部模式力常数k（a）（CC），对于33，在CCSD（T）/cc-pVDZ理论水平下计算局部模式力常数k（a）（CC）。从k（a）（CC），我们推导出相关的键强度顺序BSO n（CC），以提供定量措施的内在键强度。进行了拓扑电子密度和自然布居分析，以分析这些键的性质和补充键强度的措施。对于取代的烃系统，我们发现CC键的加强/减弱发生的共价键的性质增加/减少，通过不同的电荷离域。我们的研究结果提供了新的指导方针，理想地调节C相当于C，C=C，和C-C键强度和键断裂反应的前瞻性途径的设计。[图形]。
Substituent effects on the carbon-carbon bonds of hydrocarbons have been a topic of interest within the past seven decades as resultant information would enable one to tune the activity of CC bonds. However, current assessments of the C equivalent to C, C=C, and C-C bond strength of acetylene, ethylene, and ethane as well as their derivatives rely on indirect measures such as bond length and bond dissociation enthalpy. In this work, we introduce a quantitative measure of the intrinsic strength of C equivalent to C, C=C, and C-C bonds for a set of 40 hydrocarbon systems consisting of 3 parent structures, 36 hydrocarbon derivatives involving CF3, CH3, CHO, F, NH2, or OH groups, and a conjugated system, based on vibrational spectroscopy. Local mode force constants k(a)(CC) were computed at the CCSD(T)/cc-pVTZ level of theory for systems 1-32 and 34-40 and CCSD(T)/cc-pVDZ for 33. From k(a)(CC), we derived related bond strength orders BSO n(CC) in order to provide quantitative measures of intrinsic bond strength. Topological electron density and natural population analyses were carried out as to analyze the nature of these bonds and complement bond strength measures. For substituted hydrocarbon systems, we found the strengthening/weakening of the CC bonds occurs as the covalent nature of the bond increases/decreases by means of varying charge delocalizations. Our findings provide new guidelines for desirably modulating C equivalent to C, C=C, and C-C bond strength and for the design of prospective pathways for bond cleavage reactions.[GRAPHICS].