Calculations of the 13C nuclear screening tensors for coumarin and some methoxycoumarins
- 1 August 1977
- journal article
- Published by Wiley in Magnetic Resonance in Chemistry
- Vol. 9 (8) , 477-479
- https://doi.org/10.1002/mrc.1270090806
Abstract
INDO calculations are reported of the 13C nuclear screening tensors in coumarin and some of its methoxy derivatives. Calculations based upon a linear combination of gauge dependent atomic orbitals and those using an uncoupled Hartree–Fock approach are described. Comparison with the results of less sophisticated calculations shows that changes in the excitation energies, bond orders and the 〈r−3〉2p term are together responsible for determining the 13C chemical shifts.Keywords
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