物理化学学报Issue(1)：35-42,8.DOI:10.3866/PKU.WHXB201210261
用扩展的Istomin-Palm模型估算双向延伸化合物R1-Y-R2生成焓
An Extended Istomin-Palm Model for Estimating the Enthalpies of Formation of the Two-Direction Extending Compounds R1-Y-R2
摘要
Abstract
Istomin and Palm proposed a model, ΔfH0(RX)=h[R]+h[X]+φ[R]φ[X], (h[R] and h[X] are the contributions of alkyl R and substituent X to theΔfH0(RX), respectively.φ[R]φ[X] represents the interaction of alkyl R and substituent X), to express the enthalpies of formation of monoderivatives of hydrocarbonsΔfH0(RX). However, in two-direction extending compounds R1-Y-R2, the Y substituent is attached to two alkyl groups (R1 and R2), and the intramolecular interactions are more complicated than that in monosubstituted alkanes. Thus, the Istomin-Palm model must be modified. In this work, the interactions among Y, R1, and R2 contributing to the enthalpy of formation,ΔfH0(R1-Y-R2), are divided into three parts: <br> the interaction between R1Y and R2 (φ[R2]φ[R1Y]), the interaction between YR2 and R1 (φ[R1]φ[YR2]), and the interaction between R1 and R2 (ψ[R1]ψ[R2]). These three interactions replace theφ[R]φ[X] term, and a new extended Istomin-Palm model,ΔfH0(R1-Y-R2)=h[R1]+h[R2]+h[Y]+φ[R1]φ[YR2]+φ[R2]φ[R1Y]+ψ[R1]ψ[R2], is proposed. In this model, h[Y] is the contribution of substituent Y to ΔfH0(R1-Y-R2). The h[R1] and h[R2] terms are the contributions of alkyls R1 and R2 toΔfH0(R1-Y-R2). The last three terms are the total contribution of interactions among Y, R1, and R2. Furthermore, the interaction potential index IPI(X) reported in our recent work (Wu, Y. X.; Cao, C. Z.; Yuan, H. Chin. J. Chem. Phys. 2012, 25 (2), 153.) was employed to express the intrinsic interaction of Y with alkyl groups (φ[Y]), and two general expressions were established to estimate ΔfH0, in which one is for thioethers, secondary amines, ethers, and ketones, and the other is for esters. These two estimating equations give results, which are as accurate as G3 and G3MP2 models in calculating ΔfH0 for R1-Y-R2 compounds. Moreover, our method avoids time consuming calculations.关键词
生成焓/取代基/相互作用/双向延伸化合物/相互作用势指数Key words
Enthalpy of formation/Substituent/Interaction/Two-direction extending compound/Interaction potential index分类
化学化工引用本文复制引用
曹晨忠,武亚新..用扩展的Istomin-Palm模型估算双向延伸化合物R1-Y-R2生成焓[J].物理化学学报,2013,(1):35-42,8.基金项目
国家自然科学基金(21072053)和湖南省教育厅科研基金(10K025)资助项目 （21072053）
