Complexes, containing inequivalent

In an effort to understand the mechanisms involved in formation of complex orientational structures of adsorbed molecules and to describe orientational, vibrational, and electronic excitations in systems of this kind, a new approach to solid surface theory has been developed which treats the properties of two-dimensional dipole systems.61,109,121 In adsorbed layers, dipole forces are the main contributors to lateral interactions both of dynamic dipole moments of vibrational or electronic molecular excitations and of static dipole moments (for polar molecules). In the previous chapter, we demonstrated that all the information on lateral interactions within a system is carried by the Fourier components of the dipole-dipole interaction tensors. In this chapter, we consider basic spectral parameters for two-dimensional lattice systems in which the unit cells contain several inequivalent molecules. As seen from Sec. 2.1, such structures are intrinsic in many systems of adsorbed molecules. For the Fourier components in question, the lattice-sublattice relations will be derived which enable, in particular, various parameters of orientational structures on a complex lattice to be expressed in terms of known characteristics of its Bravais sublattices. In the framework of such a treatment, the ground state of the system concerned as well as the infrared-active spectral frequencies of valence dipole vibrations will be elucidated. 

As for the dinuclear complexes, one might now ask how closely do the synthetic materials correspond overall to the native site should it contain an Mn4 aggregate. There are Indeed several features which again suggest that close approach to the native site may have been achieved (1) four Mn atoms in two Inequivalent pairs with two distinct Mn...Mn separations (24) ... 

The ozonide ion O3 has been clearly characterized by EPR and reflectance spectroscopy. Labeling experiments with 170 indicate that the O3 species contains three inequivalent oxygens forming a bond angle of about 110° and that it decomposes slowly at room temperature to form O ". A second type of species has been reported as O3 but has very different characteristics, since it is stable only at low temperatures and labeling experiments with 170, which indicate two equivalent nuclei, are difficult to interpret the balance of the evidence points toward a more complex polyoxygen species (see Section V,A). The data for O4 indicates that it is likely to exist on the surface under special conditions and we expect to see this confirmed by further studies. 

PI (Men = 2.58BM). The monoclinic crystals contain the six-coordinate [Ni(m-stien)2(H20)2](Cl2CHC02)2-2H20 while the triclinic form contains two inequivalent complexes, one square planar, [Ni(m-stien)2](Cl2CHC02)2, the other six-coordinate, [Ni(m-stien)2(Cl2CHC02)2]. 

The stepped frequency approach has been adopted in a range of more complex zirconium-containing compounds including NaZr03,223 Na2Zr-SiC>5,224 where the two crystallographically inequivalent zirconium sites could... 

Complexes of cobalt containing PCF3 groups have been prepared independently by two groups, (116, 117) and parameters reported are shown with structures [220] to [224]. The P-CF3 coupling constant is increased in each case compared with that in the free ligand, as expected. Compound [222] appears from the spectra to be a mixture of isomers a and b the separation of the second order doublet for the major isomer is 88 Hz. The spectrum of [223] is also second order, with a major doublet separation of 68 Hz. Compound [224] shows inequivalent CF3 groups attached to phosphorus, and a bent Co-Co bond is invoked to account for this. (117)... 

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