Chiral self-assembly

Zsila, F., J. Deli, and M. Simonyi. 2001a. Color and chirality Self-assemblies in flower petals. Planta 213 937-942. 

To address this issue, several researchers have developed models of chiral self-assembly. In this section, we review these models. We begin with models based on nonchiral mechanisms and argue that they all have limitations in identifying a mechanism to select a particular tubule radius. We then discuss models based on the elastic properties of chiral membranes and argue that they provide a plausible approach to understanding the formation of tubules and helical ribbons. Most of this discussion was previously presented in our recent theoretical review article.139... 

The basic concept behind all models of chiral self-assembly can be stated as follows. In general, chiral molecules do not pack parallel to their neighbors but rather pack at a slight angle with respect to their neighbors. This favored packing can be visualized by the packing of hard screws,6 as illustrated in... 

Fiedler, D., Pagliero, D., Brumaghim, J.L., Bergman, R.G. and Raymond, K.N. (2004) Encapsulation of cationic ruthenium complexes into a chiral self-assembled cage. Inorg. Chem., 43 (3), 846-848. 

Femtosecond fluorescence upconversion studies of chiral self-assembled supramolecules in solution... 

Notably, even if the V monomer precursors (1) are racemic at the V center in solution, only a particular arrangement of two V monomers among possible structural arrangements is allowed as a stable structure at the Si02 surface, creating a new chiral V center (2) to provide a chiral reaction space for the enantioselective catalysis. Chiral self-assembly is a common phenomenon that is applied to other catalytic materials on surfaces. 

Supramolecular Metal Complexes Chiral Self-Assembled Supramolecular Helicates Since the first introduction of the term helicate by Lehn et al. in 1987,58 there have been a number of investigations of self-assembled supramolecules with... 

We present here a few examples of enantiomeric supramolecular absolute structures. In fact, many supramolecular diastereomers with chiral ligands have been isolated stereoselectively. For example, enantiomers of the chiral self-assembled triple helicates trinuclear [Ni3(L)3](C104)6 (L = tris(bpy)) and dinuclear [Co2(L)3]4 + (L = 5-bismpmb) were partially resolved by SP Sephadex chromatography.63,64 The ligands and structures are given in Figure 5.17a and b. 

Enantioselectivity control in a [2 + 2]-photocydoaddition reaction was achieved in a chiral, self-assembled host. Fluoranthenes and N-cyclohexylmaleimide underwent an intramolecular reaction in a cage made of M6L4, with the metal M being palladium (II) coordinated to a chiral diamine, and the ligand Lbeing2,4,6-tris(4 -pyridyl)-l,3,5-triazine. Up to 50% ee was observed [117]. 

Some chiral self-assembling systems are able to incorporate enantiomers of opposite chirality into the supramolecular structure because the chiral centre is relatively remote from the moiety that is involved in self-assembly [18,19]. By contrast, NDI... 

Keywords bridged silsesquioxanes, chirality, self-assembly... 

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