Dodecanethiol ligands

Scheme 3 Syntheses of various AFAT-AuNPs (using the ligand substitution procedure) for the selective recognition and titration of oxo-anions (for instance, 18-Fc means AuNPs with 18% AFAT ligand and 82% dodecanethiolate ligand)...

Fig. 9.2. High Resolution Transmission Electron Microscopic (HRTEM) image of Au nanoparticles stabilized by dodecanethiol ligand molecules after SMAD and digestive ripening procedure. (Reprinted from Stoeva, S. et al J. Phys. Chem. B, 2003,107,7441-7448, Fig. 11(c), by permission of the American Chemical Society, copyright 2002, American Chemical Society.)...

Short alkanes such as decane and dodecane are completely miscible in sc-CO2 at moderate pressures and temperatures. Based on the earlier simulations, it would seem that nanocrystals capped with dodecanethiol should disperse in sc-CO2 at moderate conditions however, this is not the case. Gold and silver nanocrystals capped with dodecanethiol ligands were exposed to SC-CO2 at pressures as high as 483 bar and temperatures up to 80 C without any visible dispersibility. This indicates that ligands with better CO2 compatibility need to be developed to allow for effective dispersibility. The dodecanethiol capped nanocrystals were dispersible in sc-ethane, as the solvent-ligand interactions were much more compatible. 

Figure 3.8 Various components of the interaction potential between two 5-nm gold nanoparticle molecules with dodecanethiol ligands.

Figure 3.8 shows the interaction potential between two 5-nm gold nanoparticle molecules with dodecanethiol ligands, the sum of Equations (3.3), (3.6), (3.7), and (3.8). 

In an attempt to create particles with different sizes and properties, ligands other than dodecanethiol were used to create polydispersed colloids from the SMAD method. Thus, dodecylamine, trioctyl phosphine, and dodecyl alcohol were used in addition to dodecanethiol. The results of these studies led to nearly monodispersed stable colloids for the phosphine protected particles at 6.3 nm in diameter (Figure 13). 

Astruc and co-workers have prepared the amidoferrocenylalkylthiol (AFAT)-gold nanoparticle system depicted as 110 [76]. The proportion of AFAT to dodecanethiol obtained by ligand substitution on different batches of dode-... 

Very recently Beer and co-workers have developed a surface-enhanced optical anion sensor based on gold nanoparticles [78]. Dodecanethiol-stablised gold nanoparticles were modified by ligand substitution with a disulphide-substituted zinc porphyrin 113 to provide 30 and 80 receptors per nanoparticle. Titration of both the free receptor and the modified nanoparticles with various... 

Other metallic clusters that have been demonstrated to show the QDL effect are palladium [116, 117], silver [118] and copper [119]. Palladium MFCs capped with mixed monolayers of hexanethiolate/dodecanethiolate and ferrocene thiolate ligands are prepared in a manner similar to that employed for gold MFCs. The DPV studies exhibit a quantized charging effect but the current peaks are not as well defined as those observed for Au-MPCs. Capacitance values of the order of 0.35 aF are obtained, indicating smaller core sizes or thicker monolayer dielectrics [116]. 

Figure 3.10 A large, 2d superlattice of 5.5-nin gold Danoparticles ligated with dodecanethiol on a silicon nitride surface. Note hexatic, close-pacfced structure (like pennies on a table top) and the spacing between the nanoparticles, which is filled with the alkane chains of the ligands, which keeps the gold particles fiom touching, which would lead to irreversible aggregation.

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