Packing motifs

S- -S contacts between rings within the dimer (ds.,.s=3.217 A).71 Recently Awaga and co-workers72 showed that on heating, BDTA melted and immediately re-solidified to form a new phase, which was paramagnetic in the solid state. In the case of BDTA there are (at least) two stable solid-state structures but their packing motifs are such that they preclude interconversion between them. As a consequence melting the dimer then allows the substantial... 

The electron-donor molecule most studied as a component of cation-radical salts is BEDT-TTF. Over 50 superconducting salts containing this molecule have been reported in the literature. Several distinct packing motifs [6-8] of the BEDT-TTF radical cations have yielded superconducting salts, but the most studied of these are... 

Scheme 2 Four common packing motifs of the BEDT-TTF molecule. The black bars represent and end-on view of the molecule, looking down the long molecular axis. The a-phase, which is quite similar to the 0-phase, is characterized as a herringbone structure, the P -phase contains stacks of slipped dimers, the K-phase contains orthogonally arranged dimers, and the P"-phase is characterized by canted stacks of donor molecules...

Fig. 2 Packing diagram of the layered structure of kl-(BEDT-TTF)2Cu(CF3)4(TCE) (top). The packing motif of the BEDT-TTF electron donor molecules (lower left). The anion layer contains both disordered [Cu(CF3)4] anions and neutral TCE solvent molecules (lower right). In all cases, hydrogen atoms have been omitted for clarity...

Fig. 7 The novel packing motif of a" -(BEDT-TTF)4([Fe(C5H4S03)2]-6H20. Regions containing a-type circled with a dotted line, while regions with P"-packing are highlighted with an oval (top). The anionic layer is characterized by an extensive hydrogen bonding network (dashed bonds) between water molecules and the sulfonate functionality of the anion...

Fig. 10 Side view of the cation radical stacks in the [Au(ppy)(C8H4S8)]2[PF6] (left) and [Au(ppy) (C8H4S602)]2[BF4] (right) salts. The packing motif is influenced by S—S contacts in the [Au(ppy) (C8H4S8)]2[PF6] salt and O-HC hydrogen bonds in [Au(ppy)(C8H4S602)]2[BF4]...

Figure 8. The 2D herringbone packing motif in (a) naphthalene, (b) biphenyl, and (c) anthracene as viewed normal to the ab plane, (d) Anticipated 1 3 pillar (black)-guest (grey) herringbone packing within the gallery regions of a templated...

Figure 14.6 Structural arrangement of peptides (a and c) 1 (EIAQLEYEISQLEQ) and (b and d) 3 (EIAYIEQEISQLEQ) in the coiled coil or amyloid-fike /8-sheet packing motifs. Amino acids are represented with upper case standard single letter code whereas position in the heptad repeat is indicated in lowercase italic. Reprinted from Dong and Hartgerink (2007). Copyright 2007 American Chemical Society.

Explain the fact that benzene adopts a herringbone packing motif (Figure 1.20), whereas higher aromatic hydrocarbons possess y-type or graphitic interactions. 

The dominant supramolecular synthon present in these compounds is the pi-halogen dimer (PHD) interaction [22], This efficient packing motif results from two inversion-related host molecules packing such that one bromine atom from each is situated in the cleft of its V-shaped partner (Figure 3), in addition to aromatic endo, endo-facial interaction. 

Fig. 2.2. Examples of herringbone and herringbone-like packing motifs for several rigid-backbone, small molecule, organic semiconductors A) pentacene [54a] B) pyrene [54b] C) perylene [54c]...

The metastable, 2-D packing motif presented by some Pcs adsorbed on Ag(l 11) has also prompted the utilization of such ensembles as templates for the organization of complementary guest molecules such as fullerenes [193] or corannulenes [194], giving rise to the formation of two-component, 2-D architectures. More recently, a similar approach has been used to prepare a surface-supported, three-component system. In fact, the immersion of an Au substrate into a solution containing both a ZnPc and a Zn porphyrin led to the formation of a highly ordered, 2-D arrangement of both Pc and porphyrin which can act as a bimolecular chessboard toward the supramolecular assembly of a third component (i.e., C6o fullerene) which is selectively trapped in the open spaces (Fig. 25) [195],... 

---