Phenothiazine Scope: Steric Strain Induced Planarization and Excimer Formation

We present a spectroscopic investigation on the effect of changing the position where carbazole is attached to biphenyl in carbazolebiphenyl (CBP) on the triplet state energies and the propensity to excimer formation. For this, two CBP derivatives have been prepared with the carbazole moieties attached at the ( para ) 4- and 4 ′ -positions ( p CBP) and at the ( meta ) 3- and 3 ′ -positions ( m CBP) of the biphenyls. These compounds are compared to analogous m CDBP and p CDBP, i.e. two highly twisted carbazoledimethylbiphenyls, which have a high triplet energy at about 3.0 eV and tend to form triplet excimers in a neat film. This torsion in the structure is associated with localization of the excited state onto the carbazole moieties. We find that in m CBP and p CBP, excimer formation is prevented by localization of the triplet excited state onto the central moiety. As conjugation can continue from the central biphenyls into the nitrogen of the carbazole in the para -connected p CBP, emission involves mainly the benzidine. By contrast, the meta -linkage in m CBP limits conjugation to the central biphenyl. The associated shorter conjugation length is the reason for the higher triplet energy of 2.8 eV in m CBP compared with the 2.65 eV in p CBP.

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Importance of transition-state steric strain in the nitrogen inversion of hydrazines

Journal of the Chemical Society Chemical Communications ◽

10.1039/c39740000823 ◽

1974 ◽

pp. 823 ◽

Cited By ~ 6

Author(s):

Victor J. Baker ◽

Alan R. Katritzky ◽

Jean-Pierre Majoral ◽

Stephen F. Nelsen ◽

Patrick J. Hintz

Keyword(s):

Transition State ◽

Steric Strain ◽

Nitrogen Inversion

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Excimer Formation by Steric Twisting in Carbazole and Triphenylamine-Based Host Materials

The Journal of Physical Chemistry C ◽

10.1021/jp512772j ◽

2015 ◽

Vol 119 (5) ◽

pp. 2380-2387 ◽

Cited By ~ 45

Author(s):

Sergey A. Bagnich ◽

Stavros Athanasopoulos ◽

Alexander Rudnick ◽

Pamela Schroegel ◽

Irene Bauer ◽

...

Keyword(s):

Host Materials ◽

Excimer Formation

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A method for measuring membrane microviscosity using pyrene excimer formation. Application to human erythrocyte ghosts

Biochimica et Biophysica Acta (BBA) - Biomembranes ◽

10.1016/0005-2736(79)90277-3 ◽

1979 ◽

Vol 552 (2) ◽

pp. 201-211 ◽

Cited By ~ 35

Author(s):

Micah Dembo ◽

Victor Glushko ◽

Mary E Aberlin ◽

Martin Sonenberg

Keyword(s):

Human Erythrocyte ◽

Erythrocyte Ghosts ◽

Membrane Microviscosity ◽

Excimer Formation ◽

Pyrene Excimer Formation

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Excimer emission based on the control of molecular structure and intermolecular interactions

Journal of Materials Chemistry C ◽

10.1039/c5tc03289j ◽

2016 ◽

Vol 4 (14) ◽

pp. 2784-2792 ◽

Cited By ~ 32

Author(s):

Jaehyun Lee ◽

Hyocheol Jung ◽

Hwangyu Shin ◽

Joonghan Kim ◽

Daisuke Yokoyama ◽

...

Keyword(s):

Molecular Structure ◽

Intermolecular Interactions ◽

Excimer Emission ◽

Oled Device ◽

Center Position ◽

Excimer Formation

The wavelength of excimer formation and efficiency of an OLED device were controlled through the change of the center position of the triple-core chromophore.

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Faraday communications. Intramolecular excimer formation in 1,5-di(9-anthryl)-n-pentane

Journal of the Chemical Society Faraday Transactions ◽

10.1039/ft9949002845 ◽

1994 ◽

Vol 90 (18) ◽

pp. 2845 ◽

Cited By ~ 1

Author(s):

T. A. Smith ◽

G. D. Scholes ◽

G. O. Turner ◽

K. P. Ghiggino

Keyword(s):

Intramolecular Excimer ◽

Excimer Formation

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Unfolding of Helical Poly(L-Glutamic Acid) in N,N-Dimethylformamide Probed by Pyrene Excimer Fluorescence (PEF)

Polymers ◽

10.3390/polym13111690 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1690

Author(s):

Weize Yuan ◽

Remi Casier ◽

Jean Duhamel

Keyword(s):

Glutamic Acid ◽

Local Density ◽

Guanidine Hydrochloride ◽

Racemic Mixture ◽

Excimer Fluorescence ◽

Excimer Formation ◽

Blob Model ◽

Α Helix ◽

The Relationship ◽

Pyrene Excimer Formation

The denaturation undergone by α–helical poly(L-glutamic acid) (PLGA) in N,N-dimethylformamide upon addition of guanidine hydrochloride (GdHCl) was characterized by comparing the fluorescence of a series of PLGA constructs randomly labeled with the dye pyrene (Py-PLGA) to that of a series of Py-PDLGA samples prepared from a racemic mixture of D,L-glutamic acid. The process of pyrene excimer formation (PEF) was taken advantage of to probe changes in the conformation of α–helical Py-PLGA. Fluorescence Blob Model (FBM) analysis of the fluorescence decays of the Py-PLGA and Py-PDLGA constructs yielded the average number (<Nblob>) of glutamic acids located inside a blob, which represented the volume probed by an excited pyrenyl label. <Nblob> remained constant for randomly coiled Py-PDLGA but decreased from ~20 to ~10 glutamic acids for the Py-PLGA samples as GdHCl was added to the solution. The decrease in <Nblob> reflected the decrease in the local density of PLGA as the α–helix unraveled in solution. The changes in <Nblob> with GdHCl concentration was used to determine the change in Gibbs energy required to denature the PLGA α–helix in DMF. The relationship between <Nblob> and the local density of macromolecules can now be applied to characterize the conformation of macromolecules in solution.

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