Hexyl chain

Fig. 5. Conjectured cross-sectional representation of complex for cucur-bituril plus C HjNHfCHjj NH-(CHjj NHj in acidic and in alkaline solution. Outlines are drawn as for Fig, 4. In all probability a slight buckling of the hexyl chain actually occurs in the upper situation, better filling the cavity and bringing the ammonium ions into improved alignment with the carbonyl dipoles of the receptor, from [8] with permission...

The stereoselective total synthesis of ( )-lepadiformine was accomplished in the laboratory of S.M. Weinreb. The introduction of the hexyl chain in a stereoselective fashion was achieved by a Grignard reaction to an iminium salt during the last steps of the synthetic sequence. The iminium salt was generated in situ from an a-amino nitrile with boron trifluoride etherate, and the addition of hexylmagnesium bromide gave a 3 1 mixture of alkylated products favoring the desired stereoisomer. Removal of the benzyl group completed the total synthesis. 

An asymmetric hexyl-substituted quarterthiophene derivative (32a) has been reported[202] and compared to unsubstituted and di-hexyl substituted analogues (Figure 3.1.11). The authors showed an increase in mobility from 2 x 10 cm V s with no side chains (27a), to 0.02 cm V s with one hexyl chain (32a), and 0.06 cm V s for the symmetric hexyl substituted quaterthiophene (28a). Fused ben-zothiophene end-groups (32b) also improved the mobility (0.01 cm V- s" ) compared to unsubstituted 4T (27a), but to a lesser extent. [202]... 

Ackermann, J. et al., Effectof end-substitution of hexyl chains on the growth and electrical... 

The first soluble oligomer with significant field-effect mobility was 5,5" -dihexyl-quaterthiophene, described by the Gamier group in 1998 [25]. The chemical stracture is shown in Figure 5.3.1. The compound exhibits a mesophase transistion below 100°C. The hexyl chains improve the ordering of the compound relative to unsubstituted quaterthiophene, which in turn is believed to lead to improved mobility as... 

The effect of the nature of the terminal group and the position of the imine link has also been investigated. Thus, when hexyl chains are substituted at each end of a rhenium complex with the same motif as 12, a nematic phase was observed (Cr 129N 167 1). Moreover, when one of the two hexyl chains were replaced by one (Figure 28) or two perfluorinated chains, the mesophase was changed to SmA phase, and occurred at higher temperatures, with decomposition taking place in the mesophase. ... 

Fig. 5.33 View along the crystallographic c-axis (above) and side view (below) of the crystal packing of the cyclotetraikosiphenylene. Hydrogen atoms, chloroform molecules and hexyl chains have been omitted for clarity.

And the longest chain that has been explored in this Muni Metro series is the six-carbon hexyl chain which is, quite logically, the L-series, sort of the end of the Taraval line (see under METHYL-J for an explanation). The central compound for all the L-compounds was the ketone 1-(3,4-methylenedioxyphenyl)-2-hexanone, which was prepared by the Grignard reagent of (n)-amyl bromide with piperonal to give... 

Figure 9 Cartoon of an NaDEHP rod (in the solid state or as a crystallite in solution) and its constituents. (a) Side view of the rod s crystalline core (of length L) consisting of a stack of disks (with average height h), each occupied by two (white) or three (shaded) Na PO ion pairs. The protrusion (5-I-) and the recess (S-) symbolize the net overall axial displacement of the Na+ ions relative to the PO4 ions, which results in a permanent dipole moment. The exposed polar ends of the rod are hydrated, (b) The PO4 tetrahedron of NaDEHP (showing only the main hexyl chains), (c) Top view of a disk, indicating the preferential orientation of the POj groups (Na" " ions not shown). The length / of an NaDEHP molecule is the radius r of the crystallite. (Reprinted with permission from Ref. 50. Copyright 1995 American Chemical Society)...

The hexylbenzene spectrum (Figure 13.35cT) bears similarities to those of hexane and benzene. Peaks for C—H stretching are found both above and below 3000 cm for sp and sp C—H stretching, respectively. The benzene ring is represented in the weak peak at 1496 cm The three peaks between 750 and 690 cm include bending modes for the hexyl chain and the ring. 

The phenanthroline-containing ligands 66a and b (Chart 5.19) have been incorporated into Cu complexes and electropolymerized [74]. The geometry at the Cu" " center in poly-[Cu(66a)2] and poly-[Cu(66b)2] was probed using X-ray absorption. It was shown that the Cu centers in poly-[Cu(66b)2] contribute to the conductivity of the film. Removal of the copper with cyanide causes the structure of the polymer to irreversibly collapse in poly-[Cu(66a)2], whereas the presence of the hexyl chains in poly-[Cu(66b)2] help to maintain an intact polymer structure after the removal of the metal. 

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