Gold complexes stabilizers

Hosomi et al. reported an unprecedented hydrosilylation of ketones and imines displaying remarkable chemoselectivity that enabled ketones to be differentiated from aldehydes. Although the active species were not dear, they accepted that monomeric gold complexes stabilized by excess of tributylphosphine played a crucial role in controlling the reaction [190] (Scheme 8.30). 

The remarkable stability of the gold complexes is due to significant metal-metal bonding. However, their isolation and structural study are remarkable and greatly contributed to our knowledge of higher-coordinate carbocations. 

Bardaji, M., Laguna, A., Perez, M.R. and Jones, P.G. (2002) Unexpected ring-opening reaction to a new cyanamide-fhiolate ligand stabilized as a dinuclear gold complex. Organometallics, 21, 1877. 

Scheme 1. The solvent-free controlled thermolysis of gold(I) thiolate complex producing gold nanoparticles stabilized by alkyl groups derived from the precursor.

Scheme 2. Production of size-regulated gold nanoparticles stabilized by primary amines, tertiary amines, sulfides, and thiols formed by the controlled thermolysis of gold(I) thiolate complex in the presence of amine (reprinted from Ref. [11], 2005, with permission from Elsevier).

The treatment of 2-amino-4,5-dihydrothiazole with [Au(ACAC)(PPh3)] evolves to an unprecedented ring-opening reaction to give the new ligand (2-cyanamide)ethylthiolate, stabilized as the dinuclear gold complex (Equation (42)).2315... 

Bis -7r-coordination has been realized in tweezers-type dialkynyltitanium complexes, as shown in Scheme 81.74 92,93,141,320,321 Theoretical calculations were carried out for the model system [Cl2Ti(C=CH)2]MMe with M = Gu, Ag, Au. It has been shown that the gold complex has the lowest stability in the series.321... 

Ferrous ferric oxide showed a different concentration-time profile with change of pH in comparison to the two other materials - it was linear, while the decline in gold concentration was rather steep for FeOOH and AI2O3 within the first minutes of the experiment. This behavior was observed under all pH conditions. Furthermore, in the case of Fe304 it was seen that an increase in pH resulted in a gradual increase in speed of gold removal from solution, e.g., while it took 90 min to remove all gold present at pH=2 and 3 it took about 60 min at pH=4 and had finished after 5 min at pH=5 and 6, which can also be explained with the mentioned speciation effect in connection with the associated different complex stabilities. 

As already mentioned, CAAC ligands can stabilize electron-deficient metal centers such as in cationic gold complexes. Complex 29 catalyzes a very unique reaction of enamines with acetylene, which produces a cumulene and an imine... 

Any of the particle sols prepared above may be used to adsorb macromolecules to create gold probes. To concentrate the suspensions, the solutions may be filtered through a small-pore filter. Centrifugation also may be done. Each protein-gold complexation should be optimized for the proper amount of protein to add to maintain stability of the colloid. This can be done according to the method described in Section 1. 

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