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Reexamination of the π‐bond strengths within H 2 C=XH n systems: A theoretical study
Author(s) -
Chen JunXian,
Kim Chang Kon,
Lee Hai Whang,
Xue Ying,
Kim Chan Kyung
Publication year - 2011
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.21718
Subject(s) - extant taxon , chemistry , basis set , computational chemistry , set (abstract data type) , electronic correlation , lone pair , divalent , bond length , basis (linear algebra) , thermodynamics , atomic physics , statistical physics , molecule , mathematics , physics , computer science , density functional theory , geometry , organic chemistry , evolutionary biology , biology , programming language
The accurate determination of π‐bond energies, D π , in doubly‐bonded species has been an important issue in theoretical chemistry. The procedure using the divalent state stabilization energy defined by Walsh has been suggested, and the procedure seems to be conceptually reasonable and applicable to all kinds of doubly‐bonded species. Therefore, the aim of this study was to examine whether the procedure could be a reliable methodology for estimating the D π values for a variety of H 2 C=XH n species. To achieve a higher accuracy, the D π values were estimated at QCISD(T)/6‐311++G(3df,2p) level of theory combined with isogyric correction. The D π values estimated in this work were in excellent agreement with the extant literature values. On the other hand, in determining accurate D π values for doubly bonded species, especially in species with lone‐pair electrons such as H 2 C=O, it has been found that consideration of highly sophisticated electron correlation effects could be important. However, sufficiently accurate D π values have been obtainable at QCISD(T) or CCSD(T) levels with a 6‐311++G(3df,2p) basis set on geometries at relatively inferior correlated levels such as MP2 and B3LYP levels with a 6‐31+G(d) basis set. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011