Multiple-interaction self-assembly

Figure 8 Ring-and-strings self-assembly filamentous ligand (17) combines with cyclic ligand (18) to form pseudorotaxane [Cu(17)(18)]+ upon treatment with Cu1. Multiple-interaction self-assembly (uni-/metal-mediated) combining (17), (18), Cu1 and Ru11 generates the catenane (19).

Two main types of multiple-interaction self-assembly have been demonstrated 25 (i) those involving the formation of two or more different types of coordinate bonds (metal-mediated or... 

Figure 9 Multiple-interaction self-assembly (multi-mediated) coordinate bond formation induces assembly of the metallocycle (20). Hydrophobic- and 7r-interactions, along with an entropy contribution, produce the...

The foniiation of 4, therefore, involved several different noncovalent interactions. The cyclization step was brought about by the formation of Pd—N coordinate bonds that is, by a metal-mediated process. The interlocking step involved n- and hydrophobie/hydrophilic-mediated processes, along with an entropic effect. Catenane 4 can. therefore, be considered an example of a multi-mediated,"" multiple-interaction self-assembly. Fujita referred to such processes as ""double-molecular recognition"" procedures, in which the two interlocking molecules bind each other in their cavities. 

Multiple-interaction self-assembly involves the formation of more than one type of interaction. Illustrated in Fig. 3b is a multiple-interaction process in which two types of coordinate bonds are formed (i.e., double subroutine self-assembly). Depicted in Fig. 3c is a multiple-interaction process in which one type of coordinate bond and one type of hydrogen bond are formed (i.e., a multiple molecular recognition process). Processes like that depicted in Fig. 3 b involve mediation by one class of interaction only, and can therefore be referred to as unmediated.Processes of the type depicted in Fig. 3c involve mediation by two different classes of interaction and are therefore refeiTed to as multimediated. ° ... 

Fig. 3 Classes of self-assembly The forination of metal helicates by (a) single-interaction self-assembly, (b) unime-diated multiple-interaction self-assembly, and (c) multimediated multiple-interaction self-assembly. The circles and diamonds represent metal ions with preferences to bind the semicircular and half-diamond binding sites, respectively, on the hybrid ligand strands.

Swiegers. G.F. Malefetse. T.J. Multiple-interaction self-assembly in coordination chemistry. J. Inch Phenom. Macrocycl. Chem. 2001. 40, 253-264. 

Single/Multiple Interaction Self-Assembly Descriptive terms pertaining to the... 

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... 

To examine monolayers on liquid surfaces in situ, multiple interactions by mounting mirrors above and below the surface have been used. X-ray reflectivity measurements have been used to study the counterion overlayers at the interface between electrolyte solutions and monolayers of carboxylic acids terminated alkanethiols self-assemblies on Au (Birdi, 1999). 

Having discussed self-assembly strategies toward noncovalently functionalized side chain supramolecular polymers as well as studies toward the orthogonahty of using multiple noncovalent interactions in the same system, this section presents some of the potential applications of these systems as reported in the literature. The apphcations based on these systems can be broadly classified into two areas 1) self-assembled functional materials and 2) functionalized reversible network formation. 

---