Supramolecular ribbon structure

A, while that between the pairs is 3.383(6) A. The 7r-stacked arrays of cations are linked by centrosymmetric pairs of Se(2)—N(l ) contacts, thereby generating ribbons running along the y-direction. These four-center Se—N supramolecular synthons, which are common in diselenadiazolylium salts and diselenadiazolyl radicals, are likely to dominate the solid-state structures of reduced diselenazolyl materials. 

Hierarchical Higher Organization - From Bilayers to Fibers and Rods Amphiphile assembly sometimes results in higher order supramolecular assemblies. Fibrous structures and helical ribbons with molecular dimensions are formed spontaneously. 

Many types of amphiphile can form these supramolecular structures (see Fig. 4.52). Most of these have the abiUty to form hydrogen bonds - hydrogen bond formation significantly increases the stabihty of a supramolecular assembly. The presence of a chiral center sometimes leads to the formation of ribbon-Uke structure and twisted fibers. 

FIGURE 1. Supramolecular structure of the complexes between isosteviol and aniline (94), N,N-dimethylaniline (X = N(CH3)2) or toluene (X = CH3) (95). Isosteviol is represented as ribbon helices. Adapted from Reference 159... 

Fig. 17 Supramolecular architectures from self-assembly of rod-coil macrocycles, a Body-centered orthorhombic structures from ribbon-like aggregates b body-centered tetragonal structures from barrel-like aggregates...

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