Mean bond disruption enthalpy

Bonds between many neutral ligands and transition metal atoms in low oxidation states, have mean bond disruption enthalpies in the range 80-200 kJ mol 1 (9). Bonds to charged ligands, e.g. 

In the previous exercise (whose outcome was not very successful), we used a new concept to assess the thermodynamic stability of chemical bonds the mean bond dissociation enthalpy (also known as mean bond disruption enthalpy). It is represented by DH° or by (DH°) (the symbol we adopt). As indicated, for... 

As a consequence monomeric complexes are obtained much more easily. Also, the tendency to bridge lanthanide centers is less distinct and, for example, a small cluster chemistry as it exists for alkoxides, e.g. OiPr [13] and OtBu derivatives [14], is not yet known. However, the Ln-N(amide) bond is less strong than the Ln-O(alkoxide) bond, and even comparable to Ln-C(alkyl) bonds, which has an effect in synthetic chemistry. This has been confirmed by the determination of absolute bond disruption enthalpies D by means of calorimetric titrations for the representative systems Cp Sm X (X = OrBu, D = 82.4 kcalmol-1 NMe2, 48.2 CH(SiMe3)2, 47.0) [15]. 

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