Metallosupramolecular architecture

Stadler, A.-M., Kyritsakas, N., Graff, R. and Lehn, J.-M. (2006) Formation of rack- and grid-type metallosupramolecular architectures and generation of molecular motion by reversible uncoiling of helical ligand strands. Chem.-Eur. J., 12, 4503. 

Fig. 5 Generation of multifunctionality/multivalency by self-assembly. Octa-valency from either hydrazide and dialdehyde components/subunits (left), or preformed ligands (top right) in the case of the formation of [2x2] grid-type metallosupramolecular architectures. Insert. Schematic representation of the generation of hexadeca-valency from tetrasubstituted ligand molecules...

Self-organization with selection occurs in the metal cation driven build-up of [2x2] grid-type metallosupramolecular architectures by dynamic ligand generation with selection of the proper components [53-56], as well as in the self-sensing process enabled by the cation-induced recomposition of a dynamic polymer [57]. In these cases the evolution of the system is driven by cation coordination pressure. 

Cao XY et al (2007) Generation of [2X2] grid metallosupramolecular architectures from preformed ditopic bis(acylhydrazone) ligands and through component self-assembly. Eur J Inorg Chem 2944—2965. 

In a similar approach, double-stranded helicates of various lengths that were derived from copper and silver-based metallosupramolecular architectures have also been classified by their diffusion properties and estimates of the molecular sizes made [48]. Owing to the ellipsoidal structures, it was necessary to introduce appropriate shape factors to translate the hydrodynamic radii determined directly from the unmodified Stoke-Einstein equation into dimensions that were meaningful for these assemblies. Thus, knowledge of the width of the helicates (determined from the X-ray structure of a single complex in this case) allowed the determination of their lengths from the hydrodynamic radii. The results for a series of these helicates is summarised in Table 9.9. It was further shown that 2D DOSY spectra could be employed to differentiate the helicates of different lengths when present simultaneously in a mixture. 

Elaboration of metallosupramolecular architectures through desymmet-rization selBassembly of symmetric building blocks 13CL328. 

Another interesting example of Ag(I)-backbone organometallic polymers are those based on diallylmelamine and poly-carboxylates. Silver-vinyl bonding represents a versatile synthon for the construction of polymeric metallosupramolecular architectures. The particular structural motifs result from the introduction of different auxiliary polycarboxylates into the silver/diallylmelamine system and the diverse coordination modes and conformations of diallylmelamine (Fig. 29.3) [108]. Remarkably, apparent silver-vinyl interactions with a ri mode were commonly observed in the solid-state structures of these complexes (Ag-C = 2.311(4)-2.467(5)A). In addition, they display solid-state photoluminescence and moderate thermal stabilities at room temperature. 

Ruben M et al (2004) Grid-type metal ion architectures functional metallosupramolecular arrays. Angew Chem Int Ed Engl 43 3644-3662... 

Grid-type metal ion architectures in functional metallosupramolecular arrays 04AG(E)3644. 

In this chapter, the concept of self-sorting is in the focus. The metallosupramolecular complexes discussed above combine multiple copies of the same building blocks into larger architectures. The pseudorotaxanes presented here instead combine a number of different building blocks that are positioned in the complexes with spatial control. 

Kolb U, Buscher K, Helm CA, Lindner A, Thunemann AF, Menzel M, Higuchi M, Kurth DG (2006) The solid-state architecture of a metallosupramolecular polyelectrolyte. Proc Natl Acad Sci U S A 103 10202-10206. doi 10.1073/pnas.0601092103... 

Smulders M, Riddell I, Browne C, Nitschke JR (2013) Building on architectural principles for three-dimensional metallosupramolecular construction. J Chem Soc Rev 42 1728-1735... 

Most work on metallosupramolecular dye architectures has focused on porphyrin systems. This choice was reasonable for two reasons First, porphyrins are structurally closely related to natural chlorin dyes which give their assemblies the appeal to be biomimetic . Second, porphyrins are tetradentate ligands which easily complex various metal ions in their center. As most metal ions are able to coordinate a fifth or even a sixth ligand, met-alloporphyrins are Lewis-acidic building blocks which can be organized by appropriate ligands to establish otherwise not easily accessible supramolecu-... 

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