Nuclear Magnetic Resonance: Volume 36 (Specialist Periodical Reports, Volume 36),Used

Excerpt. Reprinted by permission. All rights reserved.Nuclear Magnetic Resonance Volume 36A Review of the Literature Published between June 2005 and May 2006By G.A. Webb The Royal Society of ChemistryCopyright 2007 The Royal Society of ChemistryAll rights reserved.ISBN: 9780854043620ContentsPreface G. A. Webb, 7,NMR books and reviews W. Schilf, 22,Theoretical and physical aspects of nuclear shielding Cynthia J. Jameson and Angel C. de Dios, 50,Applications of nuclear shielding Shigeki Kuroki, Naoki Asakawa and Hidekazu Yasunaga, 72,Theoretical aspects of spinspin couplings Hiroyuki Fukui, 113,Applications of spinspin couplings Krystyna KamienskaTrela and Jacek Wjcik, 131,Nuclear spin relaxation in liquids and gases R. Ludwig, 170,Solidstate NMR spectroscopy A. E. Aliev and R. V. Law, 196,Multiple pulse NMR Daniel Nietlispach, 244,NMR of proteins and nucleic acids S. J. Matthews, 262,NMR of carbohydrates, lipids and membranes Elizabeth Hounsell, 285,Synthetic macromolecules Hiromichi Kurosu and Takeshi Yamanobe, 309,NMR in living systems Malcolm J. W. Prior, 344,Nuclear magnetic resonance imaging By Tokuko Watanabe, 363,NMR of liquid crystals and micellar solutions Maura Monduzzi and Sergio Murgia, 397,CHAPTER 1Theoretical and physical aspects of nuclear shieldingCynthia J. Jameson and Angel C. de DiosDOI: 10.1039/b618338g1. Theoretical aspects of nuclear shielding1.1 General theoryRelativistic effects on molecular magnetic properties, in particular the nuclear magnetic shielding tensor, can be significant in molecules containing heavy atoms. Many approaches have been put forward. One approach is to append the spinorbit interaction to the nonrelativistic theory. Nakatsuji et al. presented an ab initio UHF formalism for calculating the spinorbit (SO) effect without electron correlationand applied it to many systems," while Malkin et al. presented a density functional theory (DFT) formalism, and Vaara et al., on the other hand, used multiconfiguration self consistent field (MCSCF). While these works showed the importance of including the spin orbit effects, particularly to understanding the observed 'normal halogen dependence', this approach clearly is insufficient for the nuclear shielding of heavy nuclei. Several methods have been proposed to reduce the fourcomponent Dirac equation to twocomponent equations. The most successful twocomponent relativistic method to date starts with the nopair formalism and external field projectors, as developed by Douglas and Kroll and Hess. Nakatsuji and coworkers used a twocomponent quasirelativistic (QR) theory based on the DouglasKrollHess transformation, included the change of picture effect which ensures consistency with the HellmannFeynman theorem for the QR theory, adopted gaugeincluding atomic orbitals (GIAO) method for gauge origins, and incorporated electron correlation at the MP2 level in this reporting period. Fukui and Baba developed a twocomponent method that derived the expression for the nuclear shielding from the DouglasKrollHess (DKH) transformation of the nopair equation for a molecule bearing a nuclear moment and is placed in a magnetic field; they used common origin coupled HartreeFock to begin with, later introduced GIAOs. In these earlier works, the finite perturbation method was used to compute nuclear shielding values. In this reporting period, Kudo and Fukui derived expressions for the shielding tensor by analytically differentiating the electronic energy of a system based on the DouglasKrollHess approach.Earlier, Fukui, Baba and Inomata had derived a twocomponent formalism using the BreitPauli approach; the magnetic vector potential is added to the canonical momentum in the BreitPauli Hamiltonian in order to get a gaugeinvariant scheme up to order c4. In the process, a mass correction term in the shielding became apparent for the first time, arising from a second order expression containing th