Halogen-bonded supramolecular

Keywords Halogen bonding Supramolecular chemistry Crystal engineering Tecton Topology... 

Farina, A. Meille, S.V. Messina, M.T. Metrangolo, P. Resnati, G. Vecchio. G. Resolution ofracemic 1.2- dibromo-hexafluoropropane through halogen-bonded supramolecular helices. Angew. Chem.. Int. Ed. 1999, 38. 2433-2436. 

Derossi S, Brammer L, Hunter CA, Ward MD (2009) Halogen bonded supramolecular assemblies of [Ru(bipy)(CN)4] anions and A-methyl-halopyridinium cations in the solid state and in solution. Inorg Chem 48 1666-1677... 

Another example of photoresponsive liquid crystalline material based on halogen bonding appeared recently [61]. The idea here was to extend the concept of photoinduced order-disorder phase transition (Fig. Ic) from conventional photoresponsive LCs to halogen-bonded supramolecular complexes. To do this, the authors complexed azopyridines (AzPy) and molecular dihalogens (Fig. 11) in a... 

Metrangolo P, Resnati G (2007) Halogen Bonding in Supramolecular Chemistry (Chapter 5, this volume). Springer, Heidelberg... 

Metrangolo P, Resnati G (2004) Halogen bonding. In Atwood JL, Steed JW (eds) Encyclopedia of supramolecular chemistry. Dekker, New York, pp 628-635... 

As described most elegantly elsewhere in this volume, the halogen bond is an intermolecular, charge-transfer interaction between a Lewis base and an electron-deficient halogen. Other chapters that accompany this chart its use in, for example, supramolecular chemistry, molecular conductors and coordination chemistry. In this chapter, a much more recent application of halogen bonding is described, namely in the realisation of liquid-crystalline materials. 

Highly fluorinated molecules are also of significant interest for construction of supramolecular LC based on halogen bonding between perfluoroalkyl- or... 

Metrangolo, P., Meyer, F., Pilati, T., Proserpio, D. M., Resnati, G., Highly interpenetrated supramolecular networks supported by N---I halogen bonding. Chem. Eur. J. 2007,13, 5765-5772. 

Supramolecular liquid crystals have also been reported based on more unusual supramolecular interactions such as halogen bonding (Section 1.8.9).12 Neither of the components in 13.17 are mesomorphic by themselves but the presence of the highly activated iodine atom in pentafluoroiodo-benzene results in a strong N---I interaction (N---I distance 2.81 A by X-ray crystallography). These... 

F. Zordan et al., Supramolecular chemistry of halogens Complementary features of inorganic (M-X) and organic (C-X ) halogens applied to M-X—X -C halogen bond formation. J. Am. Chem. Soc. 127, 5979-5989 (2005)... 

Fig. 9 A halogen-bond mediated main-chain supramolecular liquid crystalline polymer 11-4...

A unique assembly of a crystalline hybrid supramolecular salt was achieved by reaction of 2,4-bis (3-pyridylmethyl)oxy -(l,3)-p-bu -calix[4]-crown-6 (33), hexadecafluoro-l,8-diidooctane and Csl (2(X) 4951). In its solid state, the cesium ion of the supercation was encapsulated inside the cavity created by the crown ether loop, the picolyl and inverted phenyl moieties, whereas the two iodide ions of the superanion, formed a discrete five component aggregate held together by hydrogen and halogen bonds. Similar adduct existed in solution. A combination of this calix-crown 33 and octafluoro-l,4-diiodobutane acted as an effective binary host for the selective extraction of Csl from aqueous to fluonous phase. 

Halogen atoms that are involved in halogen-bonding formation can be bound to other halogens (elemental halogens and inter halo gens) or to carbon or nitrogen atoms. The electron-pair donors can be neutral (N, O. S, Se,...) or anionic (1, Br, Cl , F. ..) species. Interaction of these motifs results in a wide diversity of supramolecular synthons (Fig. 1). 

Fig. 1 Most frequently used halogen-bonding-based supramolecular synthons. Eleetron-pair donor sites were reported in blaek, while the aeeeptor sites are in grey. (View this art in color at www.dekker.com)...

Hundreds of supramolecular structures grounded on halogen bonding were reported since the seminal work of Hassel. The following part of this article will survey some... 

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