Ultraviolet/Visible, Infrared and Raman Spectra

Furukawa, Yukio

doi:10.1002/9780470682531.pat0101

Cited by 2 publications

(3 citation statements)

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“…The observed increasing (or decreasing) exponential-like patterns of C = C and C–C bond length changes in all-trans polyenes upon systematic increase of the molecular system size is reminiscent of the structural dependencies calculated for linear acenes, closed rings or “belts” of cyclacenes and model single-walled carbon nanotubes [ 9 , 27 ]. In fact, similar to systems containing linearly conjugated benzene rings [ 27 ], polyenes show strong electron delocalization, and a saturation effect is also apparent for oligomers containing more than 6–7 C = C units.…”

Section: Resultsmentioning

confidence: 89%

“…Force constants and vibrational stretching frequencies in polyenes are directly related to their C = C and C–C bond lengths [ 9 , 45 ]. For this reason, we first analyzed in detail the patterns of B3LYP/6-311++G**-calculated C = C and C–C bond length changes upon increasing the length ( n ) of all-trans polyenes (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Anyhow, the two methods of graphical presentation seem to be equivalent, and to produce the same Y(∞), but we prefer our approach, which directly and nicely shows the convergence pattern upon increasing the chain length. Besides, it is worth mentioning that, some time ago, Furukawa [ 9 ] reported on successful fitting of polyene infrared frequencies using an exponential-like mathematical expression similar to Eq. ( 1 ).…”

Section: Resultsmentioning

confidence: 99%

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DFT studies on the structural and vibrational properties of polyenes

et al. 2016

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Detailed density functional theory (DFT) calculations on the structure and harmonic frequencies of model all-trans and all-cis polyenes were undertaken. For the first time, we report on the convergence of selected B3LYP/6-311++G** and BLYP/6-311++G** calculated structural parameters resulting from a systematic increase in polyene size (chains containing 2 to 14 C = C units). The limiting values of the structural parameters for very long chains were estimated using simple three-parameter empirical formulae. BLYP/6-311++G** calculated ν(C = C) and ν(C–C) frequencies for all-trans and all-cis polyenes containing up to 14 carbon–carbon double bonds were used to estimate these values for very long chains. Correction of raw, unscaled vibrational data was performed by comparing theoretical and experimental wavenumbers for polyenes chains containing 3 to 12 conjugated C = C units with both ends substituted by tert-butyl groups. The corrected ν(C = C) and ν(C–C) wavenumbers for all-trans molecules were used to estimate the presence of 9 – 12 C = C units in all-trans polyene pigment in red coral.Graphical abstractDetailed density functional theory (DFT) calculations on the structure and harmonic frequencies of model all-trans and all-cis polyenes were undertaken. For the first time, we report on the convergence of selected B3LYP/6-311++G** and BLYP/6-311++G** calculated structural parameters resulting from a systematic increase in polyene size (chains containing 2 to 14 C=C units). The limiting values of the structural parameters for very long chains were estimated using simple three-parameter empirical formulae.Electronic supplementary materialThe online version of this article (doi:10.1007/s00894-016-2969-1) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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