Self assembly oligomers

Soon after Guldi et al. published on their system, Stod-dart and coworkers published a report wherein dynamic chemistry was used to form self-assembled oligomers that were found to be capable of binding and, possibly even, sorting SWNTs by size. Their system is composed of 5,15-fran.y-pyridyl metalloporphyrin, 13, which can act as a linear divalent ligand and cw-protected Pd or Pt complexes (Figure 13). While neither the Pd/Pt ligand nor the porphyrin displayed an ability to solubilize SWNTs on its own, they were found to completely solubilize SWNTs in aqueous acetonitrile solutions when used in conjunction with one another. 

Self-assembled structures can be closed if all the potential binding sites are utilized, or open if they are not. Closed assemblies have a definite geometry and stoichiometry, while open assemblies exist as mixtures of oligomers or polymers of varying stoichiometry. In addition, the self-assembled structure can be classified as cooperative if the multiple binding interactions reinforce each other to yield enhanced stability, or trivial if the binding interactions do not cooperate in the... 

The self-assembly of cyclic dimers is entropically favored over the assembly of higher cyclic oligomers, but the assembly of larger oligomers is possible if the geometry of the monomer is incompatible with dimerization. 

Fig. 8.14 TEM images showing (A) self-assembled layers of individual myoglobin molecules wrapped by condensed oligomers of AMP (B) top view of single sheet showing ordered superstructure of the hydrophobic organoclay wrapped myoglobin molecules.

FIG. 38. a-D-GalNAc 2,2 -bipyridine oligomers self-assembled around a copper(II) salt.277... 

Layer-by-layer Ru3 cluster-based multilayers were fabricated onto preorganized self-assembled monolayer gold electrode surfaces by Abe et al. [15], in which [Ru3(q3-0)( i-0Ac)6(4,4/-bpy)2(C0)] was utilized as the synthetic precursor. The stepwise connection of oxo-centered triruthenium cluster units onto the gold electrode surface is a feasible approach for construction of Ru3 cluster-based oligomers on a solid surface, in which the bridging ligand 4,4 -bipyridine appears to mediate weak cluster-cluster electronic interaction between the Ru3 cluster centers. 

Cygan MT, Dunbar TD, Arnold JJ, Bumm LA, Shedlock NF, Burgin TP, Jones L II, Allara DL, Tour JM, Weiss PS (1998) Insertion, conductivity, and structures of conjugated organic oligomers in self-assembled alkanethiol monolayers on Au 111). J Am Chem Soc 120 2721-2732... 

Certain diglyceryl alkyl ethers (vide supra) that form, by self-assembly, liquid crystals have a future in nanochemistry [46, 47]. Evidently, therefore, selective catalytic synthesis of specific oligomers of glycerol in a shape selective environment (vide supra) will contribute significantly to the generation of new classes of bio-and nano-materials. 

As noted above, salt-extracted H2A H2B will form higher oligomers, fibers could be obtained from salt-extracted histones (Fig. 3c), and even octamers are now known to associate into superstructures at very high salt concentration (Wachtel and Sperling, 1979). It would therefore seem that self-assembly is a general property of histones. The pattern of complex formation of the core histones is shown schematically in Fig. 4. 

---