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A semi‐empirical MO calculation of 13 C chemical shifts—I: Alkanes
Author(s) -
Solkan V. N.,
Mamayev V. M.,
Sergeyev N. M.,
Ustynyuk Yu. A.
Publication year - 1971
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270030511
Subject(s) - chemical shift , chemistry , methane , excitation , range (aeronautics) , pentane , carbon fibers , series (stratigraphy) , atomic physics , computational chemistry , alkane , carbon 13 , thermodynamics , physics , hydrocarbon , materials science , nuclear physics , organic chemistry , quantum mechanics , paleontology , composite number , composite material , biology
13 C shielding constants have been calculated for a series of alkanes, methane to pentane. The quantities σ d and σ p have been obtained, using an average excitation energy approximation and the extended Hückel MO wave functions in terms of the Pople method. The results fit the experimental data and the VB results of Grant et al . fairly well. The quantity σ d varies within a wide range for carbon atoms of various degrees of substitution. Two conformations of the hydrocarbons studied have been calculated. The results show that the 13 C chemical shifts may be used for conformational analysis.