Ligand exchange defined

The stability of adducts 146, 147, and 150 was supported by thermal gravimetric analysis (DSC/TGA) ill-defined mass-loss begins at 200 °C. On the other hand, no ligand exchange was observed with r/s pyridine (C5D5N) up to 200 °C in toluene solutions. 

Y > Sm > Nd) [108]. Neodymium surface species 9 generated by silylamido alkoxo secondary ligand exchange was more efficient in e-CL polymerization, producing well-defined poly(CL)s with controllable molecular weight and polydis-persity [114]. 

Transition metal-catalyzed allylic alkylation is generally considered to involve mechanistically four fundamental steps as shown in Scheme 1 coordination, oxidative addition, ligand exchange, and reductive elimination. A key step of the catalytic cycle is an initial formation of a (7r-allyl)metal complex and its reactivity. The soft carbon-centered nucleophiles, defined as those derived from conjugate acids whose pAj, < 25, usually attack the allyl ligand from the opposite side... 

This is an electron transfer to the solvent, in which a hydrated electron is formed. In this complex there are well defined d-d transitions in the VIS and near UV (NUV), and CT bands in the UV regions. Irradiation in the d-d bands leads to ligand exchange, for instance to photoaquation in water. Irradiation in the CT bands results in electron transfer to the solvent. This provides a very good example of the dependence of the nature of photochemical reactions on irradiation wavelength in metal complexes. 

More recently three other mononuclear [Fe(SR)4]- complexes containing monodentate thiolate have been structurally defined. In these SR = SPh-,219 SEt-219 and 2,3,5,6-tetramethylben-zenethiolate.220 Sterically hindered thiolate ligands appear to stabilize the [Fe(SR)4] coordination unit and thus provide a means for the preparation by ligand exchange of the previously elusive (non-hindered) monodentate tetrathiolato iron(III) complexes. 

Reactions occurring in pristine or polluted waters typically include acid-base (protolysis), electron transfer (redox), electron-sharing, complexa-tion, ligand exchange, and light-induced reactions. The master variables here are normally pH and pE, as defined in Chapter 2. Such reactions are normally responsible for the incorporation, removal, or transformation of ions and compounds in aqueous media these reactions are considered next. Hereafter, we will proceed to a brief discussion of other chemical and physical phenomena mentioned above. 

EDTA) the inhibition effects can be explained by ligand exchange reactions of the type (the definive assignment of the protonation of surface species has not yet been established)... 

The exchange rate and stability of complexes are also highly dependent on the ligands and metals employed. Steric factors are often important in these ligand exchange processes. Steric and electronic properties of ligands are defined later. 

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