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Kinetically stable high-energy isomers of C14H12 and C12H10N2 derived from cis-stilbene and cis-azobenzene.

Baker J, Wolinski K - J Mol Model (2010)

Bottom Line: The isomers were obtained by applying external forces to pairs of carbon atoms from each of the benzene rings in cis-stilbene and cis-azobenzene simultaneously, and are all at least 100 kcal mol(-1) higher in energy than the starting material.Each new structure was characterized as a minimum by vibrational analysis.Despite their high energy, all of the new isomers appear to be kinetically stable with respect to rearrangement back to cis-stilbene or cis-azobenzene, respectively.

View Article: PubMed Central - PubMed

Affiliation: Parallel Quantum Solutions, 2013 Green Acres Road, Fayetteville, AR 72703, USA. baker@pqs-chem.com

ABSTRACT
Following on from our recent enforced geometry optimization (EGO) investigation of isomerization in cis-stilbene (J Comput Chem, in press) we report the discovery of two interesting new, symmetrical "fused sandwich" isomers of both cis-stilbene and the related cis-azobenzene. The isomers were obtained by applying external forces to pairs of carbon atoms from each of the benzene rings in cis-stilbene and cis-azobenzene simultaneously, and are all at least 100 kcal mol(-1) higher in energy than the starting material. Each new structure was characterized as a minimum by vibrational analysis. Despite their high energy, all of the new isomers appear to be kinetically stable with respect to rearrangement back to cis-stilbene or cis-azobenzene, respectively.

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Simulated SQM-scaled B3LYP/6-31G* IR spectra of C14H12-Cs, C14H12-C2v, and cis- and trans-stilbene
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Fig4: Simulated SQM-scaled B3LYP/6-31G* IR spectra of C14H12-Cs, C14H12-C2v, and cis- and trans-stilbene

Mentions: The simulated IR and Raman spectra for the four new “fused sandwich” isomers reported here, together with those for cis- and trans-stilbene and ditto azobenzene, are shown in Figs. 4, 5, 6, 7. These were obtained directly from the computed B3LYP/6-31G* force constant (Hessian) matrix, scaled using the five standard precomputed scaled quantum mechanical (SQM) scale factors [10] shown in Table 3, and visualized using the PQSMol graphical user interface available with PQS [9]. All spectra have been partially standardized to aid comparison.Fig. 4


Kinetically stable high-energy isomers of C14H12 and C12H10N2 derived from cis-stilbene and cis-azobenzene.

Baker J, Wolinski K - J Mol Model (2010)

Simulated SQM-scaled B3LYP/6-31G* IR spectra of C14H12-Cs, C14H12-C2v, and cis- and trans-stilbene
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102204&req=5

Fig4: Simulated SQM-scaled B3LYP/6-31G* IR spectra of C14H12-Cs, C14H12-C2v, and cis- and trans-stilbene
Mentions: The simulated IR and Raman spectra for the four new “fused sandwich” isomers reported here, together with those for cis- and trans-stilbene and ditto azobenzene, are shown in Figs. 4, 5, 6, 7. These were obtained directly from the computed B3LYP/6-31G* force constant (Hessian) matrix, scaled using the five standard precomputed scaled quantum mechanical (SQM) scale factors [10] shown in Table 3, and visualized using the PQSMol graphical user interface available with PQS [9]. All spectra have been partially standardized to aid comparison.Fig. 4

Bottom Line: The isomers were obtained by applying external forces to pairs of carbon atoms from each of the benzene rings in cis-stilbene and cis-azobenzene simultaneously, and are all at least 100 kcal mol(-1) higher in energy than the starting material.Each new structure was characterized as a minimum by vibrational analysis.Despite their high energy, all of the new isomers appear to be kinetically stable with respect to rearrangement back to cis-stilbene or cis-azobenzene, respectively.

View Article: PubMed Central - PubMed

Affiliation: Parallel Quantum Solutions, 2013 Green Acres Road, Fayetteville, AR 72703, USA. baker@pqs-chem.com

ABSTRACT
Following on from our recent enforced geometry optimization (EGO) investigation of isomerization in cis-stilbene (J Comput Chem, in press) we report the discovery of two interesting new, symmetrical "fused sandwich" isomers of both cis-stilbene and the related cis-azobenzene. The isomers were obtained by applying external forces to pairs of carbon atoms from each of the benzene rings in cis-stilbene and cis-azobenzene simultaneously, and are all at least 100 kcal mol(-1) higher in energy than the starting material. Each new structure was characterized as a minimum by vibrational analysis. Despite their high energy, all of the new isomers appear to be kinetically stable with respect to rearrangement back to cis-stilbene or cis-azobenzene, respectively.

Show MeSH
Related in: MedlinePlus