Columnar array

Most polymeric Hquid crystals are based on stiff rod-like molecular units which are called calamitic mesogens. There are some unusual polymers (which are not discussed here) that contain flat disk-like molecular units called discotic mesogens in which the disks form columnar arrays like stacks of poker chips. 

One such example was reported by Garcia-Garibay and coworkers, where the diethynylanthracene derivative 35 was induced to arrange in a columnar array... 

In the case of Pt(II), however, the d configuration leads to square-planar coordination geometries. A particular feature of these species is the doubly occupied d orbitals, which are normal to the coordination plane. This geometry facilitates the stacking of molecular units into dimers, oligomers, or columnar arrays in which the protruding orbitals can interact, leading... 

A dye molecule that has found widespread attention in the synthetic metals community is phthalocyanine 186, which can be readily made from ortho-dicyanobenzene 187 in a metal-assisted cyclotetramerization that directly provides metal complex derivatives 188 (see scheme 44) [251]. A tuning of the electronic properties is possible via the central atom and, for example, by proceeding to the related tetranaphthalene compound 189 [252]. The importance of phthalocyanines 188 in both fundamental and industrial research comes from the great number of possible applications [253]. Also, 188 can be stacked into columnar arrays by using axial ligands at the metals or by linking silicon centers as central atoms by suitable spacers [254]. The introduction of long chain alkoxy... 

The four-fold symmetry of calixarenes and resorcinar-enes relates to complexation of the siloxane. 8, with 50 in toluene. " Here the fullerenes are arranged in double columnar arrays shrouded by edge on siloxanes (Fig. 2f), the siloxanes interlocking by one of the phenyl groups of one molecule residing in the cavity of another. 

Figure 4.2 shows the molecular arrangement in the hexagonal colurmiar phase (Dj ), the symbol for which is further subscripted depending upon whether the molecules witlm the columnar arrays are ordered or disordered The lattice distance from a... 

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