Intersystem crossing processes and molecular geometry in aromatic amines

Haink, H. J.; Huber, J. Robert

doi:10.1016/0009-2614(76)80423-x

Cited by 21 publications

(14 citation statements)

References 8 publications

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“…[1][2][3][4][5][6][7][8][9][10][11] The attention mainly focussed on the equilibrium orientation of the phenyl rings, i.e., the twist angles of the phenyl groups around the C-X bonds relative to the C-X-C plane, and on the frequencies of the corresponding torsional motions. These properties are believed to play an important role in the intra-molecular dynamics as well as in the chemical behaviour of such molecules.…”

Section: Introductionmentioning

confidence: 99%

“…There is a strong relationship between the molecular geometry and the nature of electronic transitions, and Huber and co-workers concluded from an extensive study on a series of aromatic amines, whose molecular configurations gradually change from a distinctly nonplanar to a planar geometry, that ''the excited state behaviour of aromatic amines is dominated by the influence of molecular geometry on spin-orbit coupling''. [3][4][5][6] The molecular geometry thereby also influences intersystem crossing ͑ISC͒ processes. In addition, the torsional modes are expected to determine intramolecular vibrational relaxation ͑IVR͒.…”

Section: Introductionmentioning

confidence: 99%

“…15 Existing experimental data on DPA come from studies in the liquid or solid state. [1][2][3][4][5][6][16][17][18][19][20] Nonetheless, information pertaining to the geometry and dynamics of DPA and other bridged biphenylic molecules ͑C 6 H 5 ͒ 2 X is surprisingly incomplete. Those properties are best studied in the gas phase on the isolated molecule.…”

Section: Introductionmentioning

confidence: 99%

“…24,25 In solution, a fluorescence lifetime of singlet excited DPA of 3 ns has been determined. 6 The REMPI spectrum consists of many vibrational lines and the major part of the activity in the electronic spectrum is carried by two low-frequency vibrational modes that most likely involve the motion of the phenyl-rings as entities relative to the frame of the molecule. The most prominent vibrational mode has a frequency of ͑62.1Ϯ0.3͒ cm…”

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confidence: 99%

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A study on the structure and vibrations of diphenylamine by resonance-enhanced multiphoton ionization spectroscopy and ab initio calculations

Boogaarts¹,

Helden²,

Meijer³

1996

The Journal of Chemical Physics

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Laser-desorption jet-cooling has been applied in combination with mass-selective gas-phase spectroscopic techniques to study the structure and low-frequency vibrations of diphenylamine ͑DPA͒. Two-color ͑1ϩ1Ј͒ resonance-enhanced multiphoton ionization has been used to measure the vibrationally resolved excitation spectrum of the S 1 ←S 0 transition in the 305-309 nm region. Ion-dip measurements have been performed to determine the vibrational structure in the electronic ground state. The electronic spectra of DPA are dominated by long progressions in low-frequency vibrations involving the motion of the phenyl rings as a whole. For the interpretation of the experimental data ab initio calculations have been performed at the Hartree-Fock level for the S 0 -state and using single-excitation configuration interaction for the S 1 -state. The DPA molecule is found to change from a pyramidal geometry around the N-atom with unequal torsional angles of the phenyl groups in the S 0 -state to a planar geometry with equal torsional angles in the S 1 -state. The two most prominent vibrational motions are the in-phase wagging and the in-phase torsion of the phenyl rings. In addition, the resonance-enhanced multiphoton ionization spectra of the S 1 ←S 0 transition in the DPA-Ar, DPA-Kr, and DPA-Xe van der Waals complexes have been measured. From these spectra it is inferred that there is a coupling between the van der Waals modes and the low-frequency intra-molecular modes of DPA.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

A study on the structure and vibrations of diphenylamine by resonance-enhanced multiphoton ionization spectroscopy and ab initio calculations

Boogaarts¹,

Helden²,

Meijer³

1996

The Journal of Chemical Physics

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“…10 In solution a value of 3 ns has been determined for the fluorescence lifetime of singlet excited DPA. 11,12 After intersystem crossing, the long-lived triplet states of DPA can be detected using an ArF excimer laser ͑193 nm; 6.42 eV͒ for ͑time-delayed͒ ionization out of the triplet manifold.…”

Section: Methodsmentioning

confidence: 99%

Measurement of the beam intensity in a laser desorption jet-cooling mass spectrometer

Boogaarts

Meijer

1995

The Journal of Chemical Physics

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In a laser desorption jet-cooling molecular beam spectrometer the concentration of translationally and internally cooled laser desorbed organic molecules that can be achieved is experimentally determined. Sensitive direct absorption detection of laser desorbed jet-cooled diphenylamine ͑DPA͒ via cavity ring down ͑CRD͒ spectroscopy on the S 1 ←S 0 transition around 308 nm is used to measure the line-integrated absolute absorption of the pulse of laser desorbed DPA molecules. The absolute cross section for the various vibrational bands of the electronic transition that is used, is determined in a separate two-color ionization experiment. It is concluded that the optimum beam intensity that is obtained with laser desorption is comparable to the beam intensity that is obtained in the same spectrometer by conventional seeding of the desired species at a partial pressure of 10 Ϫ4 .

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Photophysical properties of the asymmetrically substituted spirobifluorenes spiro‐DPO and spiro‐MeO‐DPO

Brendel

Dias

Saragi

et al. 2009

Physica Status Solidi (a)

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The photophysical behaviour of the oxadiazolyl (PBD) and diphenylamino (TAD) substituted spirobifluorenes 2′,7′‐bis‐(N,N‐diphenylamino)‐2‐(5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazol‐2‐yl)‐9,9′‐spirobifluoren (spiro‐DPO) and 2′,7′‐bis‐(N,N‐diphenylamino)‐2‐(5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazol‐2‐yl)‐9,9′‐spirobifluoren (spiro‐MeO‐DPO) has been investigated by temperature‐dependent steady‐state absorption and luminescence spectroscopy and gated measurements. Fluorescence and phosphorescence lifetime measurements, relative quantum yields and dipole moments of the excited states have been determined. Asymmetrically substituted spirobifluorenes exhibit charge‐transfer (CT) emission due to coupling (spiroconjugation) between the fluorene fragments of spirobifluorene. They show a considerable ground‐state dipole moment and exist as equilibrating conformeres. Population of the CT state only occurs after absorption to the locally excited singlet state. The CT fluorescence is dominated by the emission of two equilibrating conformeres with similar dipole moments. At low temperature they planarize in both molecular halves and show strong phosphorescence that is still detectable at room temperature.

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Intersystem crossing processes and molecular geometry in aromatic amines

Cited by 21 publications

References 8 publications

A study on the structure and vibrations of diphenylamine by resonance-enhanced multiphoton ionization spectroscopy and ab initio calculations

A study on the structure and vibrations of diphenylamine by resonance-enhanced multiphoton ionization spectroscopy and ab initio calculations

Measurement of the beam intensity in a laser desorption jet-cooling mass spectrometer

Photophysical properties of the asymmetrically substituted spirobifluorenes spiro‐DPO and spiro‐MeO‐DPO

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