Linear tape

Hexagonal layer structure of the 1 1 complex of melamine and cyanuric acid. Three kinds of assembly in lower dimensions are possible (a) linear tape, (b) crinkled tape, and (c) rosette. 

Figure 12.1. Aromatic carboxylic acids linked via synthon I (a) 1 forms centro-symmetric dimers, (b) 2 forms linear tapes, (c) 3 forms crinkled tapes and...

Figure 12.8. (a) Flexagonal sheets formed in the co-crystal of 14 with 15. Interrupting the hydrogen bonding by substitution of 14 or 15 produces (b) linear tapes and (c)... 

Figure 12.36. Molecular isomers of 73 form (a) crinkled and (b) linear tapes mediated by aromatic-aromatic interactions.

Fig. 2 a The linear tape structure of terephthalic acid, b The zigzag tape structure of isophthalic acid, c The chicken wire sheet structure of trimesic acid [29]... 

Fig. 13a—d Solid state structural types formed by biimidazolate complexes a dimers b linear tapes c zigzag tapes d hexagonal sheets [111]... 

Fig. 22a, b Schematic representations of a linear tapes b crinkled tapes observed in structures based on N,AT-disubstituted melamines and 5,5-diethylbarbituric acid [169]... 

Extension of the ADA-DAD motif by incorporating two sets of pairs of ADA or DAD faces leads to the potential for forming sextuple hydrogen bonds. The molecules 46 and 47 have been observed to interact strongly by NMR spectroscopy to give linear tapes [207]. 

Figure 2 The structure of the hydrogen-bonded CA M lattice. Three classes of aggregates that we have observed in solution and the solid state are highlighted the rosette, crinkled tape, and linear tape motifs. The molecular strucmres of melamine and cyanuric acid and their abbreviated representation as dark and light disks are shown...

More than 40 crystal structures of DKPs (12) have already been published [30]. Almost all of these DKPs form linear tapes that pack with their long axis parallel. 

There are several pieces of backup hardware that are currently available. You can back up your information to magnetic tape, Digital Audio Tape (DAT), Digital Linear Tape (DLT), optical disk, removable hard disk, and many other removable media. The key here is that all of these media can be removed from the drive and stored in a safe place. 

D. Of the items listed, the following are valid backup hardware digital audio tape, digital linear tape, and optical disk. Because hard disks are more failure-prone than the other types listed, they make a poor backup medium. 

The complementary molecular functionality of substituted melamines and barbituric acids leads to efficient hydrogen bonding between such compounds. This pattern is shown in Figure 6 and has been used by Whitesides, Lehn and others to design various supramolecular structures such as a linear tape, a crinkled tape and a cyclic rosette [68,69]. These structures are also illustrated in... 

Figure 6 (opposite) Melamine-barbituric acid recognition pattern and a schematic depiction of the linear tape, crinkled tape and rosette structures derived from this pattern (see Zerkowski et al. [68].)... 

The iodo- nitro synthon has been used in the structures of 4-iodonitroben-zene (49), the 1 2 complex between 1,4-dinitrobenzene and 4-iodocinnamic acid (51) [81], and the 1 1 complex between 1,4-dinitrobenzene and 1,4-diiodo-benzene (50) [82]. The target in the work was the formation of a linear tape... 

Fig. 4 Two-component (left) and single-component (right) ID self-assembly. Barbituric acid (10a) and triaminopyrimidine (10b) derivatives self-assemble through complementary hydrogen bonds into linear tapes (left)." " At the right, the crystal packing of his-urea compound PI is shown, in which the urea groups form a ID (a-network) hydrogen-bonded array. (From Ref. [29].) View this art in color at www.dekker.com.)...

Figure 32 (a) Components of the 1 1 complex (b) possible cyclic dodecamer (c) possible helical aggregate (d) possible linear tape. Peripheral alkyl chains are truncated in (b)-(d) for clarity [110]. 

In another report, carboxylic acids were used to self-assemble azo dyes, which could be controlled by photoisomerization of the azobenzene dye [70]. The frans-azobenzene isomer 33 of this dye associates into hydrogen-bonded linear tapes, while the czs-azobenzene 34 yields hydrogen-bonded self-assembled tetramers that form rodlike aggregates by additional n-n stacking interactions (Fig. 23). 

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