Anion structures supramolecular assembly, self-assembled

In this volume we have collected 10 review chapters from distinguished scientists who have contributed extensively to the study and development of supramolecular assemblies that contain metals and metal-like elements with unusual structures and morphologies and possess potentially useful (and applicable) physical and biological properties. The first chapter by K. Ariga et al. is a general discussion of supramolecular structures that contain inorganic building blocks for hybrid lipid thin films, layer-by-layer assemblies, structure transcription, and functional mesoporous hybrids. This is followed by two chapters, the first by M. L. Kistler et al., who describe the self-assembly of hydrophilic polyoxometalate (POM) macro-anions and examine the structure and behavior of POM macro-ions in solution. This is followed by a chapter by S. K. Das, who provides an overview of the supramolecular features of POM-supported transition metal complexes, POM-crown ether complexes with supramolecular cations, and supramolecular water clusters associated with POMs. 

Fig. 18 Supramolecular chiral aggregates based on bis-guanidinium functional groups A chiral tetra-guanidinium units self-assemble around sulfate anions into a left-handed double helical structure B chiral bis-guanidinium unit associates with a complementary bis-anionic counterpart leading to a left-handed double helix...

Ag(bipy)(N03)]n generates another type of supramolecular isomer for self-assembly of T-shaped components. It self-assembles into linear Ag-bipy chains that cross-link via Ag-Ag bonds. This particular 3D structure has been described as a Lincoln Log type structure and exhibits a threefold level of interpenetration that is open enough to facilitate ion exchange of the loosely bound nitrate anions.47 ... 

Block co-polymers exhibit outstanding potential for a variety of applications as a result of their self-assembly into supramolecular structures (see Section 1.2.4). However, the exploration of organometallic multi-block materials was only begun in the early 1990s. Block co-polymers derived from the living anionic polymerization of vinylferrocene have been already briefly mentioned in Section 12.06.2.2.l.(i). In this section, side-chain metal-containing block co-polymers are surveyed. Examples of block co-polymers with metals in the main chain are discussed in Section 3.X. 

A number of other metal-based redox-active centers have been incorporated into supramolecular receptors, representative examples of which are displayed in Fig. 5 (Compounds 24-28). Many of these receptors electro-chemically respond to cations. but species that respond to anions and neutral molecules are also known. A number of the cation binders are organometallic crown ether and metallocrown or metallothiacrown derivatives, for example. Compound 24. Flow-ever, in many cases, the redox processes are not particularly reversible, and relatively small anodic shifts in the metal-centered redox couples are observed. A series of self-assembled [12]metallocrown-3 complexes, two of which are 25 and 26, were found by Severin to bind halide salts of small Group 1 metals strongly in organic solvents, with affinities similar to those of the cryptands. X-ray crystal structures revealed that the metal cation was... 

The crystal structure consists of 2D H-bonded networks built-up from tetrameric units through the self-assembly of Hmal anions and 2-Cl-HStb cations linked by charge-assisted carboxylate-pyridinium supramolecular heterosynthons O and C-H 0 ]. Adjacent... 

The same fluorinated mercuracycle links thiocyanate anions (in acetone solution) and the tetra-n-butylammonium salt of [(n-C6F4Hg)3SCN] has been isolated and structurally characterized [6]. The crystal structure contains a helical chain of alternating (o-C6F4FIg)3 molecules and SCN ions. The stacks are held by sulfur atoms at Hg- -S distances in the range 3.06-3.36 A, with one longer at 3.87 A. Thus, both host-guest complexation and supramolecular self-assembly if observed with these compounds. 

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