Force field methods coordination compounds

Mass-polarization, 54 Mass-velocity correction, in relativistic methods, 209, 211 Matrix element, 55, 103 McLean-Chandler basis sets, 160 Mean field approximation, 64 Metal coordination compounds, force field, 36 Metropolis sampling, in Monte Carlo techniques, 376... 

The determination of the charge distribution in a molecule, needed here for the latter term, (Ges), has been a considerable problem in force field calculations, especially for transition metal compounds (see Sections 3.2.6 and 3.3.6). Most promising but not yet fully tested for transition metal complexes are semi-empiri-cal quantum-mechanical methods[ 103,1041. Future studies might show whether a combination of approximate methods for the computation of charge distributions and solvation will lead to a reliable approximation of solvation parameters of coordination compounds. 

Note that there are two conformers, one with the two H8 atoms on the same side of the coordination plane (syn isomer) and the other with one H8 atom on each side of the coordination plane (anti isomer). Refine and save both using the MOMEC97 force field. Section 17.14 describes how to enforce planarity of a coordination compound. Two dimensional NMR methods can be used to determine which isomer dominates - as long as interconversion of the isomers is not rapid on the NMR time scale. The data used here are hypothetical and we have assumed that one isomer dominates to the exclusion of the other and that there is no interconversion, i. e., the observed NMR spectrum is that of an isomerically pure compound. 

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