Supramolecular dendrimer assemblies

8 Smith, D. K., Dendritic supermolecules - towards controllable nanomaterials , Chem. Commun. 2006, 34-44. 

The focal point is a carboxylate moiety an excellent ligand for the oxophilic lanthanides. The resulting isolation of the lanthanide ion and the antenna effects of the dendrons results in significantly enhanced lanthanide fluorescence. These kinds of species are reminiscent of the light harvesting and conversion devices we looked at in Chapter 11 and indeed the 

Work by the group of David Reinhoudt (Twente, Netherlands) has resulted in perhaps the only truly reversible, metal-coordination based dendrimer assembly strategy. Starting with the dendron core 14.4 Reinhoudt s group removed the chloride ligands with AgBp4 and coordinated the pyridyl functionality of 

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As early as 1992, Percec et al. [184] compared the similarity of supramolecular nanocylinders obtained from his amphiphilic dendrons with the supramolecular assembly of protein subunits to produce the cylindrical viral capsids that surround RNA in the tobacco mosaic virus (TMV). More recently, Percec [185] reviewed the historical inspiration provided by King s seminal Nobel work on the structure of TMV [186, 187]. Percec was able to show unequivocally that dendrons behave much like protein subunits to produce a rich variety of cylindrical and spherical supramolecular dendrimers that exhibit quasi-equivalency, much as noted in many viral capsids. Based on accelerated design strategies involving synthetic amphiphilic dendrons, Percec et al. [188-191] were able to demonstrate the quasiequivalent mimicry of biological systems by using retrostractural analysis [191] of their periodic and quasi-periodic supramolecular dendrimer assemblies, as... 

Thus, the concept and manifestation of molecular recognition mediated supramolecular self-assembly of small chemical units, be it an ABn type building block or a dendrimer molecule, have proved to be vital factors in bridging the gap between small molecules and novel new-age materials. 

Fig. 6a,b. Height micrographs obtained by tapping mode SFM from monolayers of a spherical b cylindrical molecules adsorbed on mica [84]. Top self-assembly of monodendron side groups into spherical and cylindrical supramolecular dendrimers. The process depends on the degree of polymerization of the polystyrene main chain... 

Convergent, supramolecular or more rarely divergent dendrimer assembly using a functional core unit... 

Fig. 6.11 Su pramolecular self-assembly of supramolecular dendrimers (according to Hirsch et al.)...

Figure 14.9 (a) Supramolecular dendrimer based on L-lysine derived dendrons assembled by an... 

The stepwise construction of self-assembled organic/inorganic multilayers based on multivalent supramolecular interactions between guest-functionalized dendrimers and nanoparticles and host-modified gold nanoparticles has been developed, yielding supramolecular LbL assembly (Fig. 13.8).12 Multilayer thin films composed of... 

Figure 13.15 The preparation of a multilayered supramolecular nanostructure of Au nanoparticles and dendrimers on PDMS via supramolecular LbL assembly and transfer printing onto a CD SAM.

NIL patterns were also used for the assembly of nanoparticles via supramole-cular host-guest interactions.95 The NIL-patterned substrate was functionalized with CD SAMs via a three-step synthesis process. The fabrication of 3D nanostructures was achieved by the alternating assembly of multivalent guest-functionalized dendrimers and CD-fnnctionalized Au nanoparticles.88 This methodology can be applied to various nanoparticles, regardless of their size and core material. For instance, CD-functionalized silica and polystyrene nanoparticles were adsorbed onto NIL-patterned CD SAMs with preadsorbed guest-fnnctionalized dendrimers.60 92 Recently, Huskens et al. demonstrated the supramolecular LbL assembly of 3D multicomponent nanostructures of nanoparticles by alternating assembly steps of complementary ferrocenyl-functionalized silica nanoparticles and different kinds of host-fnnctionalized nanoparticles (see Fig. 13.8).66... 

Newkome-type dendrons were attached to the carbon scaffold of SWCNTs and MWCNTs by defect group functionalization [108], First- and second-generation amine dendrons such as those depicted in Fig. 1.5 were condensed with the carboxyl groups of purified and opened SWCNTs and MWCNTs according to the car-bodiimide technique [108], These CNTderivatives can be expected to combine the characteristics of carbon nanotubes with those of dendrimers, potential building blocks for supramolecular, self-assembling and interphase systems. 

Such mesogenic systems represent a class by themselves often referred to as dendromesogens. The dendritic concept results from the self-organization of these dendromesogens into various liquid crystalline morphologies. Cylindrical supramolecular dendrimers are generally obtained by the self-assembly... 

Fig. 3 Schematic representation of the self-assembling of conical-like monodendrons into spherical supramolecular dendrimers and their self-organization into cubic phases (here Pm3n symmetry)...

Wedge-shaped dendrons such as those described above form mainly columnar and cubic phases. However, a liquid-crystalline phase with a tetragonal three-dimensional unit cell (Tet phase) containing 30 globular supramolecular dendrimers has been reported recently. Each of these supramolecular dendrimers is the result of the self-assembly of 12 dendrons, as is shown in Fig. 8 [120,121]. Interestingly, the complex tetragonal phase of symme-... 

Newkome et al. successfully prepared dendrimers with terpyridine units as linkers that are able to form supramolecular network assemblies. [54] The same authors have suggested recently to incorporate H-bonding moieties within a dendrimer to allow supramolecular network formation. [55]... 

Fig. 16. Example of a tapered block used for self-assembly into a supramolecular dendrimer...

Fig. 17. Self-assembly of tapered blocks into a supramolecular dendrimer (from ref 91 and 92)...

Reaction of dendrimers 38-[G2] with L-hexadecylamino-l-deoxylactitol led to the formation of the cationic dendrimers 39-[G2] (Scheme 27). A spontaneous supramolecular self-assembly leading to the formation of vesicles was observed by transmission electron microscopy (TEM). It was shown that the size of these vesicles was around 100 nm, and that their shell was constituted by a bilayer (thickness 10 nm) made of two lipophilic layers (thickness 3 nm) separated by a hydrophilic layer. Furthermore, preliminary experiments show that these cationic dendrimers possess an anti-HIV activity in vitro [41]. 

N. J. Tomalia, D.A. Dendrimers with hydrophobic cores and the formation of supramolecular dendrimer-surfactant assemblies. Langmuir 1997, 13. 3136-3141. 

Grimm F, Hartnagel K, Wessendorf F, Hirsch A (2009) Supramolecular self-assembly of dendrimers containing orthogonal binding motifs. Chem Commun 2009(11) 1331-1333... 

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