环戊二烯基自由基的生成焓：光声量热法和从头算研究。

Enthalpy of formation of the cyclopentadienyl radical: photoacoustic calorimetry and ab initio studies.

作者信息

Nunes Paulo M, Agapito Filipe, Costa Cabral Benedito J, Borges dos Santos Rui M, Martinho Simões José A

机构信息

Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.

出版信息

J Phys Chem A. 2006 Apr 20;110(15):5130-4. doi: 10.1021/jp060325n.

DOI:10.1021/jp060325n

PMID:16610835

Abstract

The gas-phase C-H bond dissociation enthalpy (BDE) in 1,3-cyclopentadiene has been determined by time-resolved photoacoustic calorimetry (TR-PAC) as 358 +/- 7 kJ mol(-1). Theoretical results from ab initio complete basis-set approaches, including the composite CBS-Q and CBS-QB3 procedures, and basis-set extrapolated coupled-cluster calculations (CCSD(T)) are reported. The CCSD(T) prediction for the C-H BDE of 1,3-cyclopentadiene (353.3 kJ mol(-1)) is in good agreement with the TR-PAC result. On the basis of the experimental and the theoretical values obtained, we recommend 355 +/- 8 kJ mol(-1) for the C-H BDE of 1,3-cyclopentadiene and 271 +/- 8 kJ mol(-1) for the enthalpy of formation of cyclopentadienyl radical.

摘要

通过时间分辨光声量热法（TR-PAC）测定，1,3-环戊二烯中气相C-H键解离焓（BDE）为358±7 kJ mol⁻¹。报告了从头算完全基组方法的理论结果，包括复合CBS-Q和CBS-QB3程序，以及基组外推耦合簇计算（CCSD(T)）。1,3-环戊二烯C-H BDE的CCSD(T)预测值（353.3 kJ mol⁻¹）与TR-PAC结果吻合良好。根据获得的实验值和理论值，我们推荐1,3-环戊二烯的C-H BDE为355±8 kJ mol⁻¹，环戊二烯基自由基的生成焓为271±8 kJ mol⁻¹。