Mapping the modification of ring currents induced by cyclopenta-fusion on a naphthalene core

Fowler, Patrick W.; Steiner, Erich; Acocella, Angela; Jenneskens, Leonardus W.; Havenith, Remco W. A.

doi:10.1039/b102413m

Cited by 45 publications

(53 citation statements)

References 49 publications

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“…12 and structure 8 considered here (Figure 10)), obey the AWA rule; and yet neither of the two (likewise symmetrical) de-coupled [r,s]-coronenes - [4,8]-coronene and [6,6]-coronene (coronene itself) 13 -is compliant with the AWA rule. However, it should be pointed out that very recent calculations 24 on the pcoronenes 12 by the ipso-centric ab-initio method [17][18][19][20]32,33 have disagreed with those 12 based on the rudimentary graph-theoretical HLPM formalism 1-4,9-11 being exploited here.…”

Section: Discussionmentioning

confidence: 88%

“…12 (It should however be noted that this conclusion is not supported by some very recent calculations 24 based on the 'ipso-centric' ab-initio approach). [17][18][19][20][21]32,33 The AWA model is likewise complied with 13 by the one member of the regular [r,s]-coronene series 25 in which the outer and inner rings are 'decoupled', but not by other regular [r,s]-coronenes, 25 in which these two sets of rings are 'coupled'. 13 The present account further evaluates the possible connection between the decoupled or coupled nature [17][18][19][20][21] of the outer perimeter and inner ring and compliance with, or violation of, the AWA rule.…”

Section: Introductionmentioning

confidence: 99%

“…Most super-ring 26,27 structures seem, however, to violate the AWA model when tested against the results of ab-initio ipso-centric calculations [17][18][19][20][21]32,33 and of 'pseudo-π' calculations 34 of the type frequently presented by Fowler and co-workers, and also when confronted with topological [9][10][11] π-electron ring-currents and bond-currents that we ourselves have calculated 22,23 by means of the HLPM approach. [1][2][3][4] By contrast, the present authors have recently shown 12,13 that, in a homologous series called the p-coronenes, 12 in which the inner ring and outer perimeter are 'decoupled' in the sense defined by Fowler et al, [17][18][19][20][21] the AWA rule is respected -at least, when HLPM 'topological' bond-currents are used as the criterion.…”

Section: Introductionmentioning

confidence: 99%

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An Analysis of Topological Ring-Currents and their Use in Assessing the Annulene-Within-an-Annulene Model for Super-Ring Conjugated Systems

2013

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Abstract. The Hückel-London-Pople-McWeeny approach to calculating ring currents in conjugated systems is considered in detail, especially the 'topological' variant of this formalism, particularly emphasised during the last five years. A step-by-step account is given of how these calculations are effected in practice, in such a way as to enable any interested reader to carry out these computations himself. The method is illustrated by using it to assess the applicability of the so-called 'Annulene-Within-an-Annulene (AWA) Rule' to 'super-ring' conjugated hydrocarbons -some in which the inner ring and outer perimeter are 'coupled', and others in which they are 'decoupled'. Compliance with the AWA model appears more probable in decoupled super-ring structures than in coupled ones. The Appendix touches on previous work involving Professor D. J. Klein, the honorand of this issue. (doi: 10.5562/cca2291)

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Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An Analysis of Topological Ring-Currents and their Use in Assessing the Annulene-Within-an-Annulene Model for Super-Ring Conjugated Systems

2013

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“…Since both semi-empirical [35] and ab initio [38][39][40][41] calculations as well as available single X-ray crystal structures [42,43] of CP-PAH show that the externally fused five-membered rings possess (localised) olefinic bonds, it is expected that these bonds will be most susceptible to undergo epoxidation by cytochrome P450 epoxidases present in the S9-mix (Fig. 7).…”

Section: Epoxidation Of Olefinic Bonds: Am1 Calculationsmentioning

confidence: 99%

Bacterial mutagenicity of the three isomeric dicyclopenta-fused pyrenes: the effects of dicyclopenta topology

Otero-Lobato

Jenneskens

Seinen

2004

Mutation Research/Genetic Toxicology and Environmental Mutagene

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Cyclopenta[cd]pyrene (1) and its congeners dicyclopenta [cd,mn]-(2), dicyclopenta [cd,fg]-(3), dicyclopenta [cd,jk]pyrene (4), which were all identified as constituents of combustion exhausts, as well as their partially hydrogenated derivatives 3,4-dihydrocyclopenta[cd]-(5), 1,2,4,5-tetrahydrodicyclopenta[cd,mn]-(6), 5,6,7,8-tetrahydrodicyclopenta[cd,fg]- (7) and 1,2,6,7-tetrahydrodicyclopenta[cd,jk]pyrene (8), were assayed for mutagenicity in the Salmonella typhimurium strain TA98 using different concentrations of microsomal protein in the metabolic activation system (S9-mix, with S9-fraction from liver of Aroclor-1254-treated rats: 2, 4 and 10% (v/v), respectively). Whereas a positive mutagenic response is found for 1-4 in the presence of S9-mix, 5-8 exert no mutagenicity either with or without S9-mix. Since for 1-4 the highest response is observed with S9-mix 2% (v/v) instead of the standard 4% (v/v), a one-step activation pathway, i.e. epoxidation of the five-membered ring olefinic bonds, appears to be operational. Surprisingly, 3 and, to a lesser extent, 2 (11.7 versus 4.2 His revertants/nmol) also give a positive response in the absence of S9-mix. Hence, 2 and 3 are expected to contribute to the direct-acting mutagenicity of the non-polar fraction of combustion exhausts. Presumably for the direct-acting mutagenicity one-electron transfer processes play a role in bioactivation. The experimental observations are supported by semi-empirical AM1 calculations on the possible ultimate metabolites, i.e. mono-epoxides (2a-4a), cis-di-epoxides (2b-4b) and trans-di-epoxides (2c-4c) and the related mono-hydroxy carbocations (2d-4d and 2e-4e), and the radical anions 1 •− -4 •− .

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“…It is well established that for most CP-PAHs, the double bond at the cyclopenta moiety possesses olefinic character: it represents the most localized double bond according to both theoretical (ab initio calculations) [50][51][52] and experimental data (single crystal X-ray structures) [53,54].…”

Section: Mutagenicity Assaysmentioning

confidence: 99%

CP-arene oxides: the ultimate, active mutagenic forms of cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs)

Otero-Lobato

Kaats-Richters

Koper

et al. 2005

Mutation Research/Genetic Toxicology and Environmental Mutagene

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The bacterial mutagenic response (Ames-assay, Salmonella typhimurium strain TA98 ± S9-mix) of a series of monocyclopentafused polycyclic aromatic hydrocarbons (CP-PAHs) identified in combustion exhausts, viz. cyclopenta[cd]pyrene (1), acephenanthrylene (2), aceanthrylene (3) and cyclopenta[hi]chrysene (4), is re-evaluated. The mutagenic effects are compared with those exerted by the corresponding partially hydrogenated derivatives, 3,4-dihydrocyclopenta[cd]pyrene (5), 4,5-dihydroacephenanthrylene (6), 1,2-dihydroaceanthrylene (7) and 4,5-dihydrocyclopenta[hi]chrysene (8). It is shown that the olefinic bond of the externally fused five-membered ring of 1, 3 and 4 is of importance for a positive mutagenic response. In contrast, whilst CP-PAH 2 is found inactive, its dihydro analogue (6) shows a weak metabolism-dependent response. The importance of epoxide formation at the external olefinic bond in the five-membered ring is substantiated by the bacterial mutagenic response of independently synthesized cyclopenta[cd]pyrene-3,4-epoxide (9), acephenanthrylene-4,5-epoxide (10), aceanthrylene-1,2-epoxide (11) and cyclopenta[hi]chrysene-4,5-epoxide (12). Their role as ultimate, active mutagenic forms, when CP-PAHs 1, 3 and 4 exhibit a positive mutagenic response, is confirmed. Semi-empirical Austin Model 1 (AM1) calculations on the formation of the CP-arene oxides (9-12) and their conversion into the monohydroxy-carbocations (9a-12a and 9b-12b) via epoxide-ring opening support our results. For 2 and 4, which also possess a bay-region besides an annelated cyclopenta moiety, the calculations rationalize that epoxidation at the olefinic bond of the cyclopenta moiety is favoured.

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Mapping the modification of ring currents induced by cyclopenta-fusion on a naphthalene core

Cited by 45 publications

References 49 publications

An Analysis of Topological Ring-Currents and their Use in Assessing the Annulene-Within-an-Annulene Model for Super-Ring Conjugated Systems

An Analysis of Topological Ring-Currents and their Use in Assessing the Annulene-Within-an-Annulene Model for Super-Ring Conjugated Systems

Bacterial mutagenicity of the three isomeric dicyclopenta-fused pyrenes: the effects of dicyclopenta topology

CP-arene oxides: the ultimate, active mutagenic forms of cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs)

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