http://www.mdpi.com/journal/ijms/special_issues/recent-advances-in-nuclear-magnetic-shielding-theory/ http://www.mdpi.com/1422-0067/3/8/914/ A theory for the calculation of self-energy corrections to the nuclear magnetic parameters is given in this paper. It is based on the S-matrix formulation of bound-state quantum electrodynamics (QED). Explicit expressions for the various terms of the S-matrix are given. The interpretation of the self-energy, one- and two-vertex terms and some perspective for possible future developments are discussed. http://www.mdpi.com/1422-0067/3/8/914/ Sat, 31 Aug 2002 00:00:00 CEST International Journal of Molecular Sciences 2002-08-31 3 8 Article 914 930 1422-0067 Self-energy Effects on Nuclear Magnetic Resonance Parameters within Quantum Electrodynamics Perturbation Theory 2002-08-31 doi: 10.3390/i3080914 Rodolfo H. Romero Gustavo A. Aucar http://www.mdpi.com/1422-0067/3/8/907/ NMR chemical shifts of the amide proton of a supermolecule, an Nmethylacetamide hydrogen-bonded with a formamide, were calculated as functions of hydrogen-bond length RN…O and hydrogen-bond angles by FPT-GIAO method within the framework of HF/STO 6-31++G(d,p) ab initio MO method. The calculations explained reasonably the experimental data reported previously that the isotropic proton chemical shifts move downfield with a decrease in RN…O. Further, the behavior of proton chemical shift tensor components depending on the hydrogen-bond length and hydrogen-bond angle was discussed. http://www.mdpi.com/1422-0067/3/8/907/ Sat, 31 Aug 2002 00:00:00 CEST International Journal of Molecular Sciences 2002-08-31 3 8 Article 907 913 1422-0067 Proton NMR Chemical Shift Behavior of Hydrogen-Bonded Amide Proton of Glycine-Containing Peptides and Polypeptides as Studied by ab initio MO Calculation 2002-08-31 doi: 10.3390/i3080907 S. Hori K. Yamauchi S. Kuroki I. Ando http://www.mdpi.com/1422-0067/3/8/888/ Ring formation in phosphate systems is expected to influence both the magnitude and orientation of the phosphorus (31P) nuclear magnetic resonance (NMR) chemical shielding anisotropy (CSA) tensor. Ab initio calculations of the 31P CSA tensor in both cyclic and acyclic phosphate clusters were performed as a function of the number of phosphate tetrahedral in the system. The calculation of the 31P CSA tensors employed the GAUSSIAN 98 implementation of the gauge-including atomic orbital (GIAO) method at the Hartree-Fock (HF) level. It is shown that both the 31P CSA tensor anisotropy, and the isotropic chemical shielding can be used for the identification of cyclic phosphates. The differences between the 31P CSA tensor in acyclic and cyclic phosphate systems become less pronounced with increasing number of phosphate groups within the ring. The orientation of the principal components for the 31P CSA tensor shows some variation due to cyclization, most notably with the smaller, highly strained ring systems. http://www.mdpi.com/1422-0067/3/8/888/ Sat, 31 Aug 2002 00:00:00 CEST International Journal of Molecular Sciences 2002-08-31 3 8 Article 888 906 1422-0067 Ab Initio Calculations of 31P NMR Chemical Shielding Anisotropy Tensors in Phosphates: Variations Due to Ring Formation 2002-08-31 doi: 10.3390/i3080888 Todd M. Alam http://www.mdpi.com/1422-0067/3/8/873/ Recent ab initio calculations of cobalt NMR shielding show that DFT-GIAO calculations using hybrid functionals are found to reproduce experimental values well. This method is used to calculate the variation of the cobalt NMR shielding tensor of sqaure pyramidal nitrosyl complexes with respect to the CoNO geometry and to differing basal ligands. The isotropic shielding is shown to have a large negative derivative with respect to CoX distance where X is a ligating atom.; the derivative with respect to NO distance is smaller but still significant. The zz component where z is along the CoN(NO) bond is more sensitive to the basal ligands but the other two principal components are sensitive to the CoNO geometry. http://www.mdpi.com/1422-0067/3/8/873/ Sat, 31 Aug 2002 00:00:00 CEST International Journal of Molecular Sciences 2002-08-31 3 8 Article 873 887 1422-0067 Ab Initio Calculations of Co Shielding in Model Complexes 2002-08-31 doi: 10.3390/i3080873 Elaine A. Moore http://www.mdpi.com/1422-0067/3/8/858/ Solid state 15N NMR chemical shift measurements have been performed on a series of nitro- and amino-substituted nitrogen-containing heterocycles that are of interest as potential new insensitive explosives. Due to low solubilities, many of these compounds are not amenable to study by solution state methods. Theoretical calculations of 15N chemical shift parameters have been performed on the structures of interest and are reported herein. The calculated and experimental values are in good agreement. The use of a model that includes intermolecular effects and allows the proton positions of the nearest neighbors to be optimized leads to the best agreement between calculated and experimental values. The theoretical models accurately predict the effects of nitro and amino substituents on ringnitrogen chemical shifts, explaining a seeming reversal in trend that is noted in the pyridine and pyridine-1-oxide chemical shifts of the highly substituted compounds. http://www.mdpi.com/1422-0067/3/8/858/ Sat, 31 Aug 2002 00:00:00 CEST International Journal of Molecular Sciences 2002-08-31 3 8 Article 858 872 1422-0067 15N Chemical Shifts in Energetic Materials: CP/MAS and ab Initio Studies of Aminonitropyridines, Aminonitropyrimidines, and Their N-Oxides 2002-08-31 doi: 10.3390/i3080858 Karen L. Anderson Lawrence H. Merwin William S. Wilson Julio C. Facelli http://www.mdpi.com/1422-0067/3/8/856/ n/a http://www.mdpi.com/1422-0067/3/8/856/ Sat, 31 Aug 2002 00:00:00 CEST International Journal of Molecular Sciences 2002-08-31 3 8 Editorial 856 857 1422-0067 Special Issue on Recent Advances in Nuclear Magnetic Shielding Theory 2002-08-31 doi: 10.3390/i3080856 Marta B. Ferraro