Stilbazole complexes

Hydrogen bonded dimers of 4-RF-substituted benzoic acids [119, 120, 122, 126], /rcyclohexane carboxylic acids [120], and hydrogen bonded complexes of benzoic acids with 4,4 -bipyridine and stilbazole [166, 243-246] can be regarded as supramolecular rod-like mesogens with two fluorinated chains. Figures 33 and 34 show comparisons of selected benzoic acid dimers and their bipyridine and stilbazole complexes. Comparison of the benzoic acid dimers 122 and 123 with -alkyl chains and F-terminated -alkyl chains, respectively, indicates that a single F-atom at the end of the alkyl chain reduces the mesophase stability... 

B. Langmuir-Blodgett Films of Metal Stilbazole Complexes Liquid Crystals... 

C. Mesomorphic Stilbazole Complexes of Groups 10 and 11 Metals Hydrogen-Bonded Stilbazole Mesogens... 

Fig. 14. Diagram to show (A) the first excited state of a conjugated donor/acceptor aromatic, (B) inductive charge redistribution caused by isolated donor and acceptor atoms, and (C) a hypothetical charge delocahzation in a group 8 metal stilbazole complex.

The stilbazole complexes of these metals, Pd(II), Pt(II), Ag(I), and Au(I), are considered together because a good deal can be learned by looking at them in this way, particularly as we begin to look at more highly substituted stilbazoles. The liquid-crystal aspects of the silver... 

Fig. 38. Phase diagram for the stilbazole complexes of AgDOS. Reprinted with permission from Acc. Chem. Res. 2000,33, 831. Copyright 2000 American Chemical Society.

Figure 13 Flexibly linked, dinuclear stilbazole complexes.

Figure 19 Aikanoate-substituted stilbazole complexes of palladiumflf).

Figure 22 Phase diagram, for the stilbazole complexes of silver triflate.

The ambivalent donor or acceptor role of low-valent metal carbonyl species, such as M(CO)5 [M = chromium, molybdenum, tungsten], in monometallic p-substituted pyridine (or stilbazole) complexes was investigated in detail by Kanis et al. in the early 1990s, and later by Roberto et al. (Figure 1.22). " As already seen before, when the substituent is an... 

The behavior is typical of relatively simple dipolar materials where a N phase was found at short chain lengths, giving way to a SmA phase in higher homologs. While the iridium complexes could be cycled in and out of the isotropic phase with few problems of decomposition, the rhodium complexes began to decompose rapidly on melting in air. Lateral fluorination of air-iridium stilbazole complexes strongly destabilized the mesophase the 2-fluorinated 4-alkoxystilbazole systems exhibited only monotropic N and SmA phases, whereas the structural isomeric 3-fluori-nated compounds were not mesomorphic. " ... 

Dimeric stilbazole complexes of Ir(i) 73 were reported and a very strong odd-even effect was noticed such that mesophases were observed when n = odd, but not when n = even. 

---