Место издания:The Magnetic Resonance Spectroscopy Division of the Gesellschaft Deutscher Chemiker (GDCh) Frankfurt
Первая страница:122
Последняя страница:122
Аннотация:Molecules with anisotropy of magnetic susceptibility exhibit small partial orientation in strong magnetic fields. The resulting macroscopic anisotropy may become manifest anisotropic nuclear dipolar and quadruple coupling. This very tiny effect can provide information on the spatial structure of molecules. New procedure ALIGN was suggested for quantitative simultaneous analysis of a series of strongly coupled high resolution NMR spectra recorded on spectrometers with different magnetic field strength. This technique allows accurate separation of the field-independent spin-spin and field-dependent dipole-dipole coupling constants. It gives also estimates for anisotropy and rhombicity of magnetic susceptibility tensor, which independently can be calculated quntum-mechanically with CSGT technique. We performed detailed experimental and theoretical (Gaussian-09 program suit) studies for a series of bicyclic carbo- and heterocycles. The results supported applicability of the method for structure applications.