Stability and Aromaticity of the Cyclopenta-Fused Pyrene Congeners

Havenith, Remco W. A.; Jiao, Haijun; Jenneskens, Leonardus W.; Lenthe, Joop H. van; Sarobe, Martín; Schleyer, Paul von Ragué; Kataoka, Masahiro; Necula, and Atena; Scott, Lawrence T.

doi:10.1021/ja011538n

Cited by 95 publications

(67 citation statements)

References 28 publications

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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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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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“…38 A similar behavior was found for the cyclopenta-fused pyrenes. 15,16 However, this trend is not reproduced either by the ab initio VB resonance energies (E res ) or by the ASEs.…”

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confidence: 96%

An ab Initio Valence Bond Study on Cyclopenta-Fused Naphthalenes and Fluoranthenes

2005

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To probe the effect of external cyclopenta-fusion on a naphthalene core, ab initio valence bond (VB) calculations have been performed, using strictly atomic benzene p-orbitals and p-orbitals that are allowed to delocalize, on naphthalene (1), acenaphthylene (2), pyracylene (3), cyclopenta[b,c]-acenaphthylene (4), fluoranthene (5), and cyclopenta[c,d]fluoranthene (6). For the related compounds 1-4 and 5,6 the total resonance energies (according to Pauling's definition) are similar. Partitioning of the total resonance energy in contributions from the possible 4n + 2 and 4n π-electron conjugated circuits shows that only the 6π-electron conjugated circuits (benzene-like) contribute to the resonance energy. The results show that cyclopenta-fusion does not extend the π system in the ground state; the five-membered rings act as peri-substituents. As a consequence, the differences in (total) resonance energy do not coincide with the differences in thermodynamic stability. Notwithstanding, the relative energies of the Kekulé structures can be estimated using Randić's conjugated circuits model.

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“…It is well known that the strong aromaticity is helpful for improving stability. 33,34 The nucleusindependent chemical shifts (NICS) 35 is most widely used to estimate aromaticity due to its simplicity and efficiency. The NICSs obtained at the points locating at the ring centre and at 0.5, 1.0, 1.5, and 2 Å above the ring centre are listed in table 5.…”

Section: Aromaticitymentioning

confidence: 99%

Theoretical studies on the stability of the salts formed by DTDO with HNO 3 and HN(NO 2 ) 2

2015

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Three stable conformations of salts formed from 3,6-diguanidino-1,2,4,5-tetrazine-1,4-di-N-oxide (DTDO) and HNO 3 and HN(NO 2 ) 2 were studied using the density functional theory. For two salts, free energies (Gs) and total energies (Es) of the three conformations increase in the same order. Intramolecular interactions in the three conformations, such as the hydrogen bonding interaction (E H ), the charge transfer (q), the binding energy (E b ), the dispersion energy (E dis ) and the second-order perturbation energy (E 2 ), decrease in completely opposite order to that of Gs and Es. Different conformations have distinct effects on the chemical stabilities and UV stabilities of two salts. Aromaticities of tetrazine in different conformations are slightly different. Although stabilities of the three conformations are different, their values are comparable.

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Stability and Aromaticity of the Cyclopenta-Fused Pyrene Congeners

Cited by 95 publications

References 28 publications

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

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

An ab Initio Valence Bond Study on Cyclopenta-Fused Naphthalenes and Fluoranthenes

Theoretical studies on the stability of the salts formed by DTDO with HNO 3 and HN(NO 2 ) 2

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