Supramolecular assemblies xanthate structures

There are two types of objects in supramolecular chemistry supermolecules (i.e., well-defined discrete oligomolecular species that result from the inter-molecular association of a few components), and supramolecular arrays (i.e., polymolecular entities that result from the spontaneous association of a large, undefined number of components) (4, 5). Both are observed in some metal-xanthate structures to be described herein. The most frequent intermolecular forces leading to self-assembly in metal xanthates are so-called secondary bonds . The secondary bond concept has been introduced by Nathaniel W. Alcock to describe interactions between molecules that result in interatomic distances longer than covalent bonds and shorter than the sum of van der Waals radii (6). Secondary bonds [sometimes called soft-soft interactions (7)] are typical for heavier p-block elements and play an important role as bonding motifs in supramolecular organometallic chemistry (8). Other types of intermolecular forces (e.g., Ji- -ji stacking) are also observed in the crystal structures of metal xanthates. 

Some antimony and bismuth xanthates tend to self-assemble through M - -S secondary bonds into supramolecular structures. 

Stereochemical Aspects of Metal Xanthate Complexes Molecular Structures and Supramolecular Self-Assembly... 

In this chapter, we will emphasize aspects of supramolecular self-assembly of metal xanthates, in particular for series of closely related structures. Self-assembly is a feature frequently observed in numerous xanthato complexes of soft metals, but this feature has often been ignored in the primary literature. 

Chapter 3 Stereochemical Aspects of Metal Xanthate Complexes Molecular Structures and Supramolecular Self-Assembly 127 Edward R. T. Tiekink and Ionel Haiduc... 

Among the recent reports on metal xanthate chemistry the following are mentioned, dealing with the structural diversity of nickel(II),213 zinc(II),214 mercury(II), 15 and tellurium(II) bis (xanthate) complexes,216 based upon different coordination patterns and supramolecular self-assembly. 

The crystal structures of several mercury bis(xanthates),267,268 and organomercury derivatives, including methylmercury xanthates, MeHg(S2COR) and their supramolecular self-assembly,269 and phenylmercury xanthates, PhHg(S2COR) (R = Me, Pr1,270 Et,271 have been reported. 

Casas. J.S. Castellano. E.E. Ellena, J. Haiduc. L Sanchez, A. Semeniuc, R.F. Sordo, J. Supramolecular self-assembly in the crystal structures of methylmercury xanthates. MeHgS(S)COR, R = Ft. Pr, and CH2Ph. Inorg. Chim. Acta 2002. 329, 11. 

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