Anion-directed assembly

Gale, P. A. Anion coordination and anion-directed assembly highlights from 1997 and 1998. Coord. Chem. Rev. 2000, 199, 181-233. 

Coles, S. J., Frey, J. G., Gale, P. A., et al, Anion-directed assembly the first fluoride-directed double helix. Chem. Commun. 2003, 568-569. 

Since the first examples of anion-directed assemblies were reported in the 1990s, a wide range of molecular and supramolecular systems have been successfully prepared using anions as templates. This section has been divided by the type of molecular or supramolecular species formed and, as mentioned before, it will mainly focus on systems that have been recently reported in the literature (making reference to previous examples when important for the sake of clarity and completion). 

Anion-Directed Assembly, p. 5i Guanidinium-Based Anion Receptors, p. 615 Hydrogen Bonding, p. 658 Organometallic Anion Receptors, p. 1006 Protonated Aza-Macrocycles for Anion Complexation, p. 1170... 

One of the first anion-directed assemblies is the [12]mer-curacarborand-4 (1) reported by Hawthorne in 1991. which can be prepared in high yields by reacting 1,2-dilithio-carborane with mercuric chloride (see Fig. 1). " This compound consists of four bivalent 1 2-carborane cages linked by four mercury atoms forming a macrocycle with a chloride ion located at its center. The anion displays strong Lewis-acid-base interactions with the four mercury atoms of the macrocycle. Such interactions play an important role in directing the formation of the cyclic... 

Beer recently reported the anion-directed assembly of the [2]pseudorotaxane 17. In this system (see Fig. 5), a chloride anion has been employed as the central core about which two ligands (the macrocycle and the liner species) are orthogonally disposed by means of bonding to the anion. The formation of 17 was studied in solution by UV/Vis spectroscopy and H-NMR and confirmed in the solid state by an x-ray crystal structure. While chloride was demonstrated to be a good directing agent for the formation of 1. other anions such as Br. ... 

Keegan, J. Kruger, P.E. Nieuwenhuyzen, M. O Brien, J. Martin, N. Anion directed assembly of a dinuclear double helicate. Chem. Commun. 2001, 2192 -2193. 

Amino Acids Applications, p. 42 Anion-Directed Assembly, p. 51 Anticrowns, p. 68... 

Amide- and Urea-Based Anion Receptors, p. 31 Anion-Directed Assembly, p. 5 i Catenanes and Other Interlocked Molecules, p. 206 Chemical Topology, p. 229... 

Anion-Directed Assembly, p. 51 DNA Nanotechnology, p. 475 Enzymes Characteristics and Mechanisms, p. 554 Micelles and Vesicles, p. 861 Molecular-Level Machines, p. 931 Self-Assembly Definition and Kinetic and Thermodynamic Considerations, p. 1248 Strict Self-Assembly and Self-Assembly witii Covalent Modifications, p. 1372 Viruses as Host Assemblies, p. 1563... 

Although the chanistry of anion directed assemblies is a flourishing field that can profit from the geometrical properties of anions similar to those of cations, examples of tanplated synthesis assisted by anion coordination are far less common than cationic examples. A pioneer example came from Beer s group. The authors took advantage of the tetrahedral organization of a sulfate anion coordinated to two hydrogen atoms of secondary amides (Scheme 17.3). 

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