Herringbone interaction

The only derivative that yielded crystals suitable for X-ray study [2,3-di(n-hexyloxy)anthracene (33)] showed almost exclusive edge-to-face (herringbone) interaction, with the crystallization appearing again to be driven by interactions between the alkyl chains. 

The interactions between molecules within stacks are mainly defined by k-k interactions. The interplanar distance between adjacent molecules is consistent with a van der Waals bond and equals 0.34 nm In the P modification neighboring stacks are arranged in a herringbone style. In the a form the herringbone interactions are not present. 

Phase transitions in two-dimensional layers often have very interesting and surprising features. The phase diagram of the multicomponent Widom-Rowhnson model with purely repulsive interactions contains a nontrivial phase where only one of the sublattices is preferentially occupied. Fluids and molecules adsorbed on substrate surfaces often have phase transitions at low temperatures where quantum effects have to be considered. Examples are molecular layers of H2, D2, N2 and CO molecules on graphite substrates. We review the path integral Monte Carlo (PIMC) approach to such phenomena, clarify certain experimentally observed anomalies in H2 and D2 layers, and give predictions for the order of the N2 herringbone transition. Dynamical quantum phenomena in fluids are analyzed via PIMC as well. Comparisons with the results of approximate analytical theories demonstrate the importance of the PIMC approach to phase transitions where quantum effects play a role. 

When halide anions are used as electron donors, they frequently work as bidentate modules with either Unear or angled geometries. Thus, on interaction with bidentate XB donors, linear [83,178,179] or herringbone chains [57,90,92,155,180-185] are formed. 

Concerning the Fischer-Tropsch synthesis, carbon nanomaterials have already been successfully employed as catalyst support media on a laboratory scale. The main attention in literature has been paid so far to subjects such as the comparison of functionalization techniques,9-11 the influence of promoters on the catalytic performance,1 12 and the investigations of metal particle size effects7,8 as well as of metal-support interactions.14,15 However, research was focused on one nanomaterial type only in each of these studies. Yu et al.16 compared the performance of two different kinds of nanofibers (herringbones and platelets) in the Fischer-Tropsch synthesis. A direct comparison between nanotubes and nanofibers as catalyst support media has not yet been an issue of discussion in Fischer-Tropsch investigations. In addition, a comparison with commercially used FT catalysts has up to now not been published. 

Recently, by crystal structure studies the number of different polymorphs of Copper Phthalocyanine Blue has been extended to nine, various of which are differing mainly in herringbone-type interaction [17]. 

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

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