Capping mechanisms, transition metal

In this mechanism, P-X is activated by the catalysis of activator A, and the capping agent is transferred to form a stable species AX. All currently known successful LRPs in this category use a halogen like Cl and Br as a capping agent X and a halide complex of transition metal like Cu" " and Ru as an activator A. These LRPs are commonly termed atom transfer radical polymerization (ATRP). The rate constants fea and feda defined in Scheme 3 are related to feact and fedeact by... 

State). This geometry requires one less skeletal electron pair than the capped square antiprism, that is, an antibonding orbital would be populated in the intermediate. We prefer mechanisms that both maximize metal-metal connectivity throughout the pathway and possess intermediates (or transition states) that conform to electron-counting rules. 

This study led to the observation of a reversible Mott-Hubbard metal-insulator transition in the nanocrystal ensemble wherein the coulomb gap closes at a critical distance between the particles. Tunnelling spectroscopic measurements on Aims of 2.6 nm Ag nanocrystals capped with decanethiol reveal a coulomb blockade behavior attributable to isolated nanocrystals [203]. On the other hand, nanocrystals capped with hexane and pentane thiol exhibit characteristics of strong interparticle quantum mechanical exchange (see Figure 4.28). Similar behavior was observed... 

---