Azulenoid

The ( 5,6], 3)-spheres are called fullerenes in Organic Chemistry, where fullerenes and other two-faced maps are prominent molecular models. The ( 5,7], 3)-spheres are called, in chemical context, azulenoids (see Figure 7.1 for azulene and [BCC96]). 

Figure 9.3 Two chemical azulenoid nets ([OKHy96]) the boron net YCrB4 (left) and ThMoB4 (right) they are strictly face-regular (5,7)-planes 5/fj, 7Ri (case 17)...

HaSo07] R. Hajduk, F. Kardos, and R. Sotak, On the azulenoids with large ring of 5-gons, manuscript, 2007. 

Kir94] E. C. Kirby, On toroidal azulenoids and other shapes of fullerene cage, Fullerene Science and Technology 2-4 (1994) 395-404. 

Whereas in chloroform and water, no enol form (8b) is detectable, the enol content is 5 cmol/mol in cyclohexane, 20 cmol/mol in methanol, 55 cmol/mol in 1,4-dioxane, and 95 cmol/mol in dimethyl sulfoxide. Apparently, the enol is stabilized in solvents that can act as hydrogen-bond acceptors, while the keto form is favoured in protic solvents acting as hydrogen-bond donors. 6-Hydroxy-4,8-dimethylazulene behaves similarly [59a]. In polar solvents such as acetonitrile or dimethyl sulfoxide, the enolic azulenoid structure is exclusively observed, whereas in less polar solvents, dichloromethane or chloroform, a keto/enol equilibrium in a ratio of about 3 1 is detectable by NMR measurements [59a]. 

As mentioned in Section III., B. 3., the use of the cyclic heptamethinium salt (44) in condensation-cyclization reaction provides an approach to several azulenoid compounds. But arylacetonitriles usually fail to condense with (44) under ordinary reaction conditions. The strongly electrophilic (44) reacts in an irreversible manner... 

Beck, A., Hunkier, D., and Prinzbach, H., Synthesis and electrocychsation of hendecafulvadienes azulenoid 14jt-annulenes, Tetrahedron Lett.. 24, 2151, 1983. 

For more specific cases where the surface network has a simple uniform pattern of rings, we specify the surface type and refer, for example, to a toroidal polyhex (also called a toroidal hexagonal system by John and Walther ) or a toroidal azulenoid, and so on. Others " -prefer to speak more generally of torusenes or toroidal forms of carbon or of graphitic carbon or graphite. 

Figure 13. NiceGraph drawing of a toroidal azulenoid cage with ten pentagons (reprinted from Ref. 40). NiceGraph appears to have a significant and important ability, namely, in favorable cases it can recognize genus.

Figure 81. Two Kekule structures of the cyclic azulenoid system shown in Figure 79, having df = 3 and having different numbers of disjoint conjugated circuits.

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