Electron density distributions transition metal compounds

Crystallographic studies of transition metal hydride complexes Stereochemistry of six-coordination Five-coordinate structures Stereochemistry of five-coordinate Co complexes Absolute stereochemistry of chelate complexes Stereochemistry of optically-active transition metal complexes Electron density distributions in inorganic compounds... 

Most coordination compounds have octahedral, square-planar, or tetrahedral structures. Asphericities of 3d electron-density distributions around transition metal atoms placed in an octahedral and tetrahedral environment differ distinctly from each other. Thus, they will be dealt with separately. 

The importance of the accurate structure determination of optically active transition metal compounds deserves special emphasis. If the electron-density distribution and geometrical arrangement of the atomic nuclei are well known, it is possible, at least in principle, to predict all the physical and chemical properties of the complex on the basis of quantum mechanical calculations. 

The two main methods currently used in computational and combined computational/experimental studies in the general area of transition metal coordination compounds, and specifically also with macrocyclic ligands, are DFT and MM. While DFT yields structural data, energies and molecular vibrations, as well as electronic information (the ground state wave function, spin density, charge distribution etc ), the latter is missing in MM. 

The position of an edge denotes the ionization threshold of the absorbing atom. The inflection in the initial absorption rise marks the energy value of the onset of allowed energy levels for the ejected inner electron (216). For a metal this represents the transition of an inner electron into the first empty level of the Fermi distribution (242) and in case of a compound the transition of an inner electron to the first available unoccupied outer level of proper symmetry. Chemical shifts in the absorption-edge position due to chemical combination (reflecting the initial density of states) were first observed by Bergergren (27). 

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