Oligomeric aggregates

Structure of some gold oligomeric aggregate molecules (a) Au5(mes)5 (mes = C6H3Me3-2,4,6) (b) [LAuClb, 1--------------1... 

Making use of the concept of aurophilicity, simple gold compounds can be combined to yield complicated oligomeric aggregates in designed synthesis. Figure 19.6.2 shows the structures of three oligomeric molecules. 

Solvents such as water, methanol, dioxan etc. stabilize the oligomeric associate. Hydrocarbons and their chlorinated derivatives do not associate with acrylic acid, and they shift equilibrium (28) to the left. The polymerization of an equilibrium mixture of oligomers and dimers in polar complexing solvents is almost 20 times more rapid than the polymerization of dimers only [64], Moreover, even with polymerization in bulk, it proceeds autocatalytically under these conditions. Oligomeric aggregates associate by hydrogen bonds on to the polymer matrix which is formed immediately after the start of the... 

Quaternary structure refers to the association of several polypeptide chains or subunits into a larger oligomeric aggregate unit. This structure depends on the close fit of the polypeptide subunits through interactions at their contact surfaces and with any prosthetic groups. 

At ambient temperature, capture by pyridine was fast (7.9 x 10"M- s- ), as was reaction with alcohols. Plots of kohs against alcohol concentration (at constant [Py]) were not linear, as hydrogen-bonded oligomeric aggregates reacted faster than monomeric alcohols. From the four alcohols studied, it is possible to derive a very approximate Bronsted a of 0.4 for the reaction with monomeric alcohols, with the rate for hexafluoro-2-propanol (2.9 x 10 M-... 

According to forces or bonding effects involved, we briefly describe the mechanisms of surfactant adsorption that have been iniroduced to explain how surface-active molecules may adsorb onto the solid substrates from aqueous solutions generally involving single molecules or oligomeric aggregates rather than micelles" ... 

FIGURE 4.1 Schematic model for the formation of fluoroalkyl end-capped oligomeric aggregates with the aggregation of end-capped fluoroalkyl groups. 

Fluoroalkyl end-capped oligomeric aggregates can be applicable to the encapsulation of metal flne particles such as gold nanoparticles [98-101], magnetic nanoparticles [102], palladium nanoparticles [103], zinc oxide nanoparticles [104], copper nanoparticles [105,106], and silver nanoparticles [107] to afford the colloidal stable fluorinated oligomeric nanocomposites-encapsulated these metal nanoparticles. In these nanocomposites, especially, encapsulated gold nanoparticles into these fluorinated oligomeric nanocomposite cores can afford the extremely red-shifted plasmon... 

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