Magnetic circular dichroism , solid-state

Resonance Energies. Resonance energies and the like have been calculated by various procedures for 1,5- and other naphthyridines.209,676,812,840 Ultraviolet and Visible Spectra. As well as those obtained from solution, such spectra of 1,5-naphthyridine have been measured in the vapor state830,1119 and the solid state.1094 Interpretation of the various bands has been proposed with assistance from magnetic circular dichroism data1153 and other sources.1016,1113,1336 Several types of calculation have been used to rationa-... 

The structure of Te4 has been determined (102) from the crystal structures of Te4(AlCl4)a and Te4(AlaCl7)2. In both cases the Te4 ion lies on a center of symmetry and is almost exactly square planar. The tellurium-tellurium distance of 2.66 A is significantly shorter than the tellurium-tellurium distance of 2.864 A within the spiral chain in elemental tellurium (105). This is consistent with a structure exactly analogous to that for 804 + in which each bond has 25% double bond character. The Raman spectra of Te4 in solution and the solid state are analogous to those of 804 and 84 but shifted to lower frequency (Table VIII). The magnetic circular dichroism (75) and visible and... 

Mascharak et al. 63) have prepared a structural BLM model PMAH containing pyrimidine, imidazole, and primary and secondary amine building blocks. The iron -PMAH complex was studied by X-ray absorption, magnetic circular dichroism, and resonance Raman spectroscopy 63). This Fe-BLM model exhibits a five-coordinate, square pyramidal geometry in the solid state and a distorted octahedral geometry in solution with a solvent molecule at the sixth position. Similar spectral features have been found for Fe -BLM. This PMAH-Fe" complex binds O2 to generate PMAH-Fe "-OOH, a low-spin hydroperoxo-iron(III) complex 64) able to promote the lipid peroxidation as BLM 65). 

Fig. 9. Magnetic circular dichroism selection rules. (A) Transitions between Zeeman-split y (or S) = i paramagnetic ground (G) and excited (E) states. Right circularly polarized (RCP) and left circularly polarized (LCP) transitions are indicated. (B) MCD spectra associated with the energy scheme in (A). The dashed bands correspond to individual left and right polarized transitions, whereas the solid line spectra give the dichroism. The C-term spectrum corresponds to a Gaussian band shape, which peaks at the absorption maximum, whereas an A-term reflects its first derivative which crosses zero at the absorption maximum.

Several physical methods have been employed to ascertain the existence and nature of ICs infrared (IR) absorption spectroscopy nuclear magnetic resonance (NMR) spectroscopy,14 including JH nuclear Overhauser effect (NOE) difference spectroscopy, H 2-D rotating-frame Overhauser effect spectroscopy (2-D ROESY),15 and solid-state 13C cross-polarization/magic angle spinning (CP/MAS) spectroscopy 16 induced circular dichroism (ICD) absorption spectroscopy 17 powder and singlecrystal X-ray diffraction 18 and fast atom bombardment mass spectrometry (FAB MS). 

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