Herringbone packing motif

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...

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

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. 2.2. 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]...

In cage-type A packing motifs, cyclodextrin molecules are arranged cross-wise in a herringbone mode. This packing is found for a-, / -, and y-cyclodextrins if... 

Fig. 9 A Large-scale in-situ STM image of the herringbone-type motif 11c of TMA on Au(lll)-(1 X l)/0.05 M H2SO4 in the presence of 3mM TMA, =0-20 V, iT = 270pA. The lattice vectors a and V are indicated. B High-resolution image of lie on Au(lll)-(1 x 1), Es = 0.18 V, ii = 120 pA. The experimental unit cell is outlined. C Proposed packing model of TMA in lie. The parameters of the unit cell are smnmarized in Table 1 [67]...

FIGURE 17.2 Views of the prototypical herringbone packing in poly(p-phenylene vinylene) and this motif is often seen in crystalline unsubstituted ir-conjugated polymers. (Reprinted from Winokur, M.J. and Chunwachira-siri, W., /. Polym. Sci., 41, 2630, 2003. With permission.)... 

Figure 16.3 Crystal structures of (a) a 6Tand (b) compound 67 showing characteristic herringbone and coplanar molecular packing motifs, respectively. Adapted from J. Cornil, D. Beljonne, J.-P. Calbert and J.-L. Bredas, Adv. Mater., 13, 1053 (2001). Copyright Wiley-VCH Verlag GmbH Co. KGaA. Reproduced with permission...

Examination of the crystal packing indicated that 92a exhibited an expanded herringbone pattern often found in unsubstituted acenes [75]. This undesirable packing motif is attributable to the steric bulk of the four interdigitated (triisopro-pylsilyl)ethynyl groups in 92a. 

Fig. 25.9 Schematic 2D model showing the various degenerate channel sites and unit cell structures for various threefold and fourfold channel packing motifs that are appropriate for alkali metal intercalation, (a)-(c) Sequential progression of high symmetry structures from the pristine herringbone phase, HB (a) to the intermediate x (or 120° [74]) phase (b) to the distorted-120° phase (c). (d)-(f) Sequential progression of high symmetry structures from the pristine herringbone phase, HB (d) to the intermediate stage 2 phase (e) to the final stage 1 phase.

Packing of the cyclodexthn molecules (a, P, P) within the crystal lattice of iaclusion compounds (58,59) occurs in one of two modes, described as cage and channel stmctures (Fig. 7). In channel-type inclusions, cyclodextrin molecules are stacked on top of one another like coins in a roU producing endless channels in which guest molecules are embedded (Fig. 7a). In crystal stmctures of the cage type, the cavity of one cyclodextrin molecule is blocked off on both sides by neighboring cyclodextrin molecules packed crosswise in herringbone fashion (Fig. 7b), or in a motif reminiscent of bricks in a wall (Fig. 7c). 

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