Interaction metal-ligand

MOMEC is a force field for describing transition metal coordination compounds. It was originally parameterized to use four valence terms, but not an electrostatic term. The metal-ligand interactions consist of a bond-stretch term only. The coordination sphere is maintained by nonbond interactions between ligands. MOMEC generally works reasonably well for octahedrally coordinated compounds. 

Eisenman, G., Sandblom, J., Neher, E. Metal-Ligand Interactions in Organic Chemistry and Biochemistry, Part 2, (eds. Pullman, B., Goldblum, N.), p. 1, D. Reidel, Dordrecht-Holland... 

Selective metal-ligand interactions in heterometallic transition metal clusters. E. Sappa, A. Tiripio-chio and P. Braunstein, Coord. Chem. Rev., 1985, 65, 219 (218). 

Each local metal-ligand interaction in a complex might include a contribution from K bonding. We now remove the restriction of only local <7 bonding adopted above. 

Sanders (83) constructed a supramolecular assembly of heterometal-lic porphyrins held together by different types of metal-ligand interaction. The team exploited the different kinetic and thermodynamic properties of the pyridine-zinc, carboxylate-tin, and pyridine-... 

Multipole analysis with high-resolution X-ray data for [Ni(thmbtacn)]2+ was carried out to determine the electron configuration in the C3 symmetry-adapted orbitals of the Ni ion, confirming a higher occupancy of the crystal field-stabilized t2g orbitals relative to the destabilized eg orbitals. This is interpreted in terms of a predominantly ionic metal-ligand interaction.1424... 

Micera, G. Kozlowski, H. In Handbook of Metal-Ligand Interactions in Biological Fluids. Bioinorganic Chenistry Berthon, G., Ed. Marcel Dekker New York, 1995 Vol. I, Part 3, Chapter 2, pp 707-716. 

Koopman s theorem is found to be valid only in the case of the vanadium (dA) complex 9. The amount of orbital reorganization is increasing considerably in the series 9-14-15-16. It is also found that strong metal-ligand interaction combined with low symmetry leads to extensive delocalization of the outer valence MO s especially in the cylobutadiene complex 16, only two orbitals with >80% metal character are found for which the convenient term essential 3d metal orbital would be justified. 

P 162 x 1CT4 cm-1, k0 0.5, c2 0.9, and fry 0.9 (= V23 0.5), indicating only a small degree of metal-ligand interaction for the level. It was suggested by Rettig etal. (65) that the metal orbitals (5 ) of Mn(Cp)2 were more involved in back donation to the ring than in Fe(Cp)2+ (q.v.) by virtue of the smaller apparent k values found for the former (ca. 0.5 vs. ca. 0.8). However, since the calculated parameter is actually fcy 23 this conclusion cannot be substantiated since only the product of k and V23 is currently known for Fe(Cp)2+. 

It is inappropriate in this survey to attempt to summarise in a short space the results of all the above treatments, but virtually all the calculations indicate that in M(Cp)2 species the 7r(ej) metal-ligand interaction is dominant in the metal to ring bonding. However, debate has largely been concentrated on two points, in the first place the extent of the validity (or otherwise) of Koopmans theorem, and, further, the question of the correct energetic ordering (5 < o < n or o < 5 < n) of the mainly metal tf-type orbitals. 

Fabbrizzi L., Licchelli M., Taglietti A., The Design of Fluorescent Sensors for Anions Taking Profit from the Metal-Ligand Interaction and Exploiting Two Distinct Paradigms, J. Chem. Soc., Dalton Trans. 2003 3471-3479. 

---