The out-of-plane vibrations of azulene

Steele, D.

doi:10.1016/0022-2852(65)90149-9

Cited by 18 publications

(2 citation statements)

References 14 publications

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“…11 In particular, we agree on the wavenumber of the origin, the wavenumbers of strong bands in the S 2 -S 0 excitation and emission spectra, and most of the vibrational assignments. However, an examination of important additional details which can be observed in our S 2 -S 0 spectra led us to discover some inconsistencies and errors in band assignments made in previous studies [10][11][12][13][14][16][17][18][27][28][29][30][31][32][33][34][35][36][37] of the spectroscopy and dynamics of azulene. None of these assignments involve bands which are crucial to the interpretation of the spectra of azulene's van der Waals complexes in the present work.…”

Section: Resultsmentioning

confidence: 99%

S₂−S₀ Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases

1996

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The S 2 -S 0 fluorescence emission and excitation spectra of jet-cooled azulene and its complexes with the rare gases, Ne, Ar, Kr, and Xe, have been measured. Features due to AZ‚RG n (n ) 1-4 when RG ) Ar, Kr, Xe and n ) 1 when RG ) Ne) are observed in the S 2 -S 0 fluorescence excitation spectra when azulene is coexpanded with the rare gases. The microscopic solvent shifts, δν j, of the origin bands for each complex scale linearly with the polarizability of the adatom(s), indicating that binding is dominated by dispersive interactions. This conclusion has been confirmed in calculations of the separate contributions of dispersion and induction to δν j. Mildly anharmonic progressions in very low frequency excited-state intermolecular (van der Waals) modes are attached to the origin bands of each AZ‚Kr n and AZ‚Xe n complex. The dominant progression is assigned to single quantum changes in that excited-state bending mode which involves motion of the adatom(s) in the plane perpendicular to the azulene ring containing the long (x) axis of the molecule. This assignment has been confirmed by calculating the frequencies of the bending and stretching vibrations in the ground state by using one-dimensional Morse and Taylor's series potential functions. The most stable geometries of the n ) 1-4 complexes in their ground states have been calculated by using a summation of pairwise atom-atom Lennard-Jones 6-12 potentials. The potential minima of the 1:1 complexes are located over the seven-membered ring; no second minimum is found over the five-membered ring. The most stable 1:2 species appears to be the symmetric (1 + 1) complex in which one adatom is bound on each side of the azulene surface. Some evidence of the asymmetric (2 + 0) isomer is also found.

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Section: Resultsmentioning

confidence: 99%

S₂−S₀ Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases

1996

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“…The program is documented in section D.3. It was intended to be also employed in the analysis of instantaneous normal modes of the azulene derivatives described in the previous chapter, because the use of more complex potentials, such as the ones developed by Steele [161][162][163] , in molecular dynamics programs is often not straightforward. These efforts remained unfinished.…”

Section: Interactions In Weakly Bound Noble Gas-halide Clustersmentioning

confidence: 99%

S2 State Photodissociation of Diphenylcyclopropenone, Vibrational Energy Transfer along Aliphatic Chains, and Energy Calculations of Noble Gas-Halide Clusters

Vennekate¹

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In this work, three major topics are investigated. The decarbonylation of diphenylcyclopropenone from its second excited electronic state forms the first part. This reaction was investigated using pump laser pulses of several different wavelengths (267 nm and 295-340 nm). Earlier reports [4] that excited state diphenylacetylene is generated as a product are dismissed on three grounds. First, the intensity of the S 1 state absorption of diphenylacetylene at 1553 cm −1 after decarbonylation of diphenylcyclopropenone was found to be much too weak. Second, ground state diphenylacetylene could be observed almost immediately within few picoseconds after the reaction had been triggered. Third, the pump wavelength limit of the appearance of the S 1 state absorption of diphenylacetylene was very similar in both the direct excitation of diphenylacetylene and photo-decarbonylation of diphenylcyclopropenone. The alternative hypothesis of internal conversion followed by a hot ground state reaction [5] could not be substantiated. Hence it is concluded that this reaction proceeds non-adiabatically to the electronic ground state of the product. These findings have been corroborated by model calculations and observations of the visible to near-UV transient spectra reported elsewhere [6] .In the main part, the investigation of IVR in several azulenyl-acetamides with aliphatic side chains of different lengths is reported. Three marker bands were monitored to assess the progress of intramolecular vibrational energy transport (IVR) after excitation of the azulene moiety to its S 1 state at 610 nm and the well-known subsequent internal conversion: an azulene ring distortion mode, the amide I mode of the acetamide, and a characteristic mode of a group installed at the opposite end of the chain, i.e. either an asymmetric azide stretching mode or a carbonyl mode. The side chains themselves consisted of methylene groups or ethylene glycol oligoethers. The velocity of energy loss from the azulene group -in agreement with previous research [7] -could be confirmed to saturate with increasing chain length. Energy transport was found to occur fast, with transport times approximately proportional to chain length, xiii Abstract as reported earlier for similar systems [8] , and hence concluded to be ballistic in nature. Transport efficiency, on the other hand, was found to decay greatly with chain length. Finally, the amide group presented a suitable reporter for intermediate steps of IVR, exhibiting a distinct spectral response during the progress of energy redistribution. Efforts to shed light on the underlying cause of this phenomenon as well as on the spectral signatures of the other observed marker bands through constants of anharmonicity did not yield conclusive results.The setup used for both of these experimental works consisted of a transient difference IR spectrometer using laser pulses of roughly 100 fs width, capable of monitoring the range from 1250 to 2400 cm −1 .The third part is devoted to weakly bound halide-noble gas clusters ...

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Synthesis and characterization of new derivatives of azulene, including experimental and theoretical studies of electronic and spectroscopic behavior

Förster

Hahn

Loose

et al. 2012

J of Physical Organic Chem

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Four new azulene derivatives featuring two π‐conjugated and sulfur terminated rigid side arms in the 1,3‐positions of the azulene core were designed, synthesized, and characterized. The syntheses were carried out on the basis of a palladium cross‐coupling procedure in the key reaction step. The crystal structures of the target compound 3 and of the intermediate compounds 7 and 9 have been studied. Supporting density functional theory calculations reveal insights into the electronic properties of the particular azulenes. The comparison of measured UV–Vis, infrared, and Raman data to calculated values allowed assignment of major spectral features to the particular structural differences of the new compounds and comparison to plain azulene. Cyclic voltammetry measurements were performed showing the redox characteristics of the new azulene derivatives. Copyright © 2012 John Wiley & Sons, Ltd.

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The out-of-plane vibrations of azulene

Cited by 18 publications

References 14 publications

S₂−S₀ Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases

S₂−S₀ Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases

S2 State Photodissociation of Diphenylcyclopropenone, Vibrational Energy Transfer along Aliphatic Chains, and Energy Calculations of Noble Gas-Halide Clusters

Synthesis and characterization of new derivatives of azulene, including experimental and theoretical studies of electronic and spectroscopic behavior

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The out-of-plane vibrations of azulene

Cited by 18 publications

References 14 publications

S2−S0 Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases

S2−S0 Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases

S2 State Photodissociation of Diphenylcyclopropenone, Vibrational Energy Transfer along Aliphatic Chains, and Energy Calculations of Noble Gas-Halide Clusters

Synthesis and characterization of new derivatives of azulene, including experimental and theoretical studies of electronic and spectroscopic behavior

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Product

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S₂−S₀ Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases

S₂−S₀ Spectroscopy of the van der Waals Complexes of Azulene with Rare Gases