Benzo phenanthrene, structure

These are benzo[cjphenanthrene and benz[ajanthracene which, as Hewett (36) noted in 1940, are both phenanthrene derivatives. In contrast, linear structures such as naphthacene are not associated... 

Figure 1. Structures and numbering of benzo[h]quinoline (BhQ), benzoff)quinoline (BfQ), Benzofc]phenanthridine (BcPhen) and their carbon analogues phenanthrene (Phe) and Chrysene (Chry). Adapted from Reference 26.

L. Lewis-Bevan, S. B. Little, J. R. Rabinowitz, Quantum Mechanical Studies of the Structure and Reactivities of the Diol Epoxides of Benzo[c]phenanthrene , Chem. Res. Toxicol. 1995, 8, 499 - 505. 

One starts with the IUPAC preferred name (sometimes referred to as the trivial name ) used for certain of the simple PAHs, e.g., anthracene, phenanthrene, pyrene, and fluoranthene. More complicated structures are then built up by the addition of, for example, benzo, dibenzo, or naphtho groups to the skeleton of the simple PAH. 

Most of the diphosphine complexes of silver known are of the type AgXP2, where X is a halide and P2 is a diphosphine. In general, they adopt dimeric structures in the solid state, with the exception of the silver chloride complex of 2,ll-bis(diphenylphosphinomethyl)benzo[c]-phenanthrene which is monomeric. 

In cases where the oxirane ring is unsymmetrically substituted, the product structure can be predicted on the basis of attack at the most electrophilic center. This center has the lowest Dewar reactivity number (A/,) as predicted by MO calculations. The following example is illustrative. Benzo[c]phenanthrene 5,6-oxide (31) could give rise to two different zwit-terions (237 and 238). The former has a Dewar reactivity number 1.79 and the... 

In practice, we have utilized it for the analysis of molecular systems comprised of 3 to 5 fused benzene rings. Our discussion in this document is limited to the following compounds phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(e)pyrene, benzo(a)pyrene, and dibenz(a,h)anthracene. The structures for these compounds are presented in Table I. It is important to note that the method has also been adapted to the determination of several other PAH compounds (e.g., benzo(c)phenanthrene, perylene, 3-methylcholanthrene, carbazole, 7H-dibenzo(c,g)carbazole, and indeno(l,2,3-cd)pyrene). 

Fig. 8.4 Chemical structures of PAHs (a) naphthalene (b) fluorine (c) 9-methylanthracene (d) phenanthrene (e) fluoranthene (f) pyrene (g) benzo(a)pyrene 4...

With azines the situation is varied. In the radical cations of pyridine and diazines the semi-occupied orbital is largely confined to the nn orbital(s) (see Scheme 2, structure 2), while the radical cation is of the n type with monoazanaphthalenes, -phenanthrenes and -anthracenes. The situation might change with substitution. As an example, alkylpyridine radical cations are of the n type, like the parent compound, whereas for the 2,5-dimethyl, 2-chloro, and 2-bromo derivatives the structure is of the n type [13]. Likewise, with benzo[c]cinnoline the parent compound and its alkyl derivatives give an n radical cation, but with some dimethoxy derivatives a n structure is found [14] and a switch from n to 7t structure occurs also in passing from 1,2,4,5-tetrazine to its 3,6-diamino derivatives [15]. 

Figure 2 Structures of polycyclic aromatic hydrocarbons. Symbols used in this figure and text Na (naphthalene). Ay (acetonaphthylene), Ae (acenaphthene), FI (fluorene). Pa (phenanthrene), A (anthracene), MPa (methyl phenanthrene), F (fluoranthene), Py (pyrene), BaA (benz(a)anthracene), Chy (chrysene), BlcF (benzo(k)fluoranthene), BbF (benzo(b)fluoranthene), BaP (benzo(a)pyrene), IP (indenopyrene), B(ghi)Pe (benzo(ghi)perylene), and Db(ah)A...

Benzo[b]thiepin structures are also assumed to be intermediates in sulfur extrusion reactions of cyclopropabenzothiopyrans (61JA4034 69JOC56). Phenanthrenes 74 are formed when dibenzo[b,/]thiepins 73 are desulfurized under drastic conditions (57JCS3814) (Scheme 17). 

These PAHs could be arranged so that a series of successive two- and four-carbon additions would result in all these species being produced through a buildup of rings. The additions are not random, but are determined by two simple structural features. If a PAH had a three-sided bay (concave) region (such as phenanthrene or benzo[e]pyrene), a two carbon addition closed that area (e.g., going from phenanthrene to pyrene). This is conceptually similar to a Diels-Alder reaction. 

Treatment of AgCl with 2,1 l-bis(diphenylphosphinemethyl)benzo[c] phenanthrene (P-P) in Me2CO yields [Ag(P-P)Cl)]. The X-ray structures of this and similar Cu and Au analogues show a remarkable change in P—M—P bond angle from 132° (Cu) to 141° (Ag) and 176° (Au). Conductivities of the complexes indicate that the degree of dissociation of Cl increases in the order Cumetal-chlorine bond lengths. 

Lewis-Bevan, L., Little, S. B., and Rabinowitz, J. R. (1995). Quanmm mechanical studies of the structure and reactivities of the diol epoxides of benzo[c]phenanthrene. Chem Res Toxicol 8, 499—505. Lodovici, M., Akpan, V., Giovannini, L., Migliani, E., and Dolara, P. (1998). Benzo[a]pyrene diol-epoxide DNA adducts and levels of polycyclic aromatic hydrocarbons in autoptic samples from human... 

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