Some semi-empirical molecular orbital calculations of nuclear spin-spin coupling constants

• Main Author: Khin, Tun
• Published: University of Surrey 1978
• Subjects: 538
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.461967

The main purpose of this work is to calculate the isotropic nuclear spin-spin coupling constants between nuclei other than protons of first-row atoms in a wide variety of molecular environments, with a view to gaining an understanding of the various electronic factors which determine the observed coupling constants. Chapter 1 introduces the theory and the origin of nuclear spin-spin coupling constants. Various MO calculations of nuclear spin-spin coupling constants are briefly reviewed in Chapter 2. Chapter 3 is concerned with approximate MO theories and their application to the SCPT and SOS methods employed in the present work. Chapters 4, 5, 7 and 8 record the INDO-SCPT and the INDO-SOS results for some [13]C-[13]C, [15]N-[13]C, [17]O-[13]C and [19]F-[15]N coupling constants respectively. The relative success of these methods in reproducing both the signs and magnitudes of the observed couplings is discussed in these chapters. The calculated values of [15]N-[15]N couplings obtained by the INDO-SOS method are included in Chapter In general, both the INDO-SCPT and the INDO-SOS methods provide a satisfactory account of the observed coupling constants in most of the molecules under consideration. The numerical computations were performed on an ICL-1905F machine at the University of Surrey Computing Unit and on the CDC-7600 computers of the Universities of London and Manchester.