Two different charge transfer states of photoexcited 9,9'-bianthryl in polar and nonpolar solvents characterized by nanosecond time-resolved near-IR spectroscopy in the 4500-10,500 cm(-1) region.

Transient absorption spectra of 9,9'-bianthryl (BA) in heptane, in acetonitrile, and in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (bmimTf(2)N) are observed with a nanosecond time-resolved near-IR absorption spectrometer for the wavenumber range of 4500-10,500 cm(-1) (2200-950 nm). In nonpolar heptane solution, a broad absorption band is observed at 6700 cm(-1) (1500 nm), in addition to a strong absorption band of the locally excited (LE) state centered at 9800 cm(-1) (1020 nm). The broad band is assigned to a partial charge transfer (PCT) band. The decay time constants of the PCT band and the LE band are both (13 +/- 1) ns. The agreement of the two decay constants strongly suggests that the PCT state is in equilibrium with the LE state in heptane. In acetonitrile, an absorption band of the charge transfer (CT) state is observed at 8000 cm(-1) (1250 nm). This band decays in (41 +/- 2) ns. In bmimTf(2)N, the CT band appears at 8500 cm(-1) (1180 nm) and decays in (34 +/- 1) ns. The difference in peak position for the CT bands in acetonitrile and in bmimTf(2)N, and the PCT bands in heptane, is explained well by the model based on the charge resonance between the two equivalent electronic structures of the CT state.

[1]  N. Nakashima,et al.  Picosecond Flash Spectroscopy of Solvent-Induced Intramolecular Electron Transfer in the Excited 9,9′-Bianthryl , 1976 .

[2]  H. Hartmann,et al.  Verbrennungswärmen und Resonanzenergien von mehrkernigen aromatischen Kohlenwasserstoffen , 1951 .

[3]  K. Hara,et al.  Solvent effect in an “isolated” solvated molecule in a free jet: Intramolecular charge-transfer state of solvated 9,9'-bianthryl , 1986 .

[4]  J. Warman,et al.  Symmetry breaking in the relaxed S(1) excited state of bianthryl derivatives in weakly polar solvents. , 2001, Journal of the American Chemical Society.

[5]  Klaas A. Zachariasse,et al.  Intramolecular charge transfer in the excited state Kinetics and configurational changes , 1996 .

[6]  P. Barbara,et al.  Dynamic solvent effects in the electron-transfer kinetics of S1 bianthryls , 1988 .

[7]  H. Hamaguchi,et al.  Construction of a Versatile Microsecond Time-Resolved Infrared Spectrometer , 1990 .

[8]  O. Kajimoto,et al.  Excited state dynamics of 9,9'-bianthryl clusters with H2O and Ar , 1998 .

[9]  H. Miyasaka,et al.  Ultrafast charge transfer process of 9,9'-bianthryl in imidazolium ionic liquids. , 2008, The journal of physical chemistry. B.

[10]  Manfred Schneider.  Einfache Methode für die Auswertung von Messungen der Transportphänomene , 1968 .

[11]  W. Rettig,et al.  Electron transfer and solvation in 9,9′-bianthryl and derivatives: a sub-ps fluorescence upconversion study , 2001 .

[12]  M. W. George,et al.  Nanosecond Time-Resolved Infrared Spectroscopy with a Dispersive Scanning Spectrometer , 1994 .

[13]  R. Wortmann,et al.  EFFECT OF S1 TORSIONAL DYNAMICS ON THE TIME-RESOLVED FLUORESCENCE SPECTRA OF 9,9'-BIANTHRYL IN SOLUTION , 1997 .

[14]  W. Rettig,et al.  Ultrafast electron transfer in acceptor substituted bianthryl derivatives , 2000 .

[15]  Hiro-o Hamaguchi,et al.  Charge resonance character in the charge transfer state of bianthryls: effect of symmetry breaking on time-resolved near-IR absorption spectra. , 2006, The journal of physical chemistry. A.

[16]  J. Clark,et al.  Picosecond excited-state solvation dynamics of 9,9'-bianthryl in alcohol solutions , 1987 .

[17]  Dynamic solvent effects on polar and nonpolar isomerizations , 1988 .

[18]  Wolfgang Rettig,et al.  Photoinduced Electron Transfer in Bianthryl and Cyanobianthryl in Solution: The Case for a High-Frequency Intramolecular Reaction Coordinate , 2003 .

[19]  G. M. Schneider,et al.  J. M. Prausnitz: Molecular Thermodynamics of Fluid Phase Equilibria. International Series in the Physical and Chemical Engineering Sciences. Prentice-Hall Inc., Englewood Cliffs, New Jersey, 1969. 523 Seiten Preis: 145 s , 1970 .

[20]  T. Takaya,et al.  Femtosecond electron transfer dynamics of 9,9′-bianthryl in acetonitrile as studied by time-resolved near-infrared absorption spectroscopy , 2004 .

[21]  K. Egashira,et al.  Effects of a solvent molecule on the torsional potential of 9,9'-bianthryl , 2000 .

[22]  T. Takaya,et al.  Femtosecond time-resolved absorption anisotropy spectroscopy on 9,9'-bianthryl: detection of partial intramolecular charge transfer in polar and nonpolar solvents. , 2009, The Journal of chemical physics.

[23]  H. Hamaguchi,et al.  Vibrational and electronic infrared absorption spectra of benzophenone in the lowest excited triplet state , 2005 .

[24]  H. Miyasaka,et al.  Picosecond dynamics of excited 9,9 '-bianthryl adsorbed on porous glass: Role of symmetry breaking in the ground state , 2002 .

[25]  Wolfgang Rettig,et al.  Charge-transfer rates in symmetric and symmetry-disturbed derivatives of 9,9'-bianthryl , 1989 .

[26]  K. Honma,et al.  Microscopic solvation of acetone to 9,9’‐bianthryl studied in a free jet: Polar excited state formation , 1991 .

[27]  Kimihiko Hara,et al.  The torsional potential of 9,9'-bianthryl determined by laser-induced fluorescence in a free jet , 1986 .

[28]  N. Mataga,et al.  Torsional relaxations from perpendicular to tilted configurations in the intramolecular charge transfer of excited 9,9′-bianthryl as studied by femtosecond-picosecond time-resolved absorption spectral measurements in solution , 1996 .

[29]  O. Kajimoto,et al.  Rotational coherence spectroscopy of 9,9′-bianthyrl and its van der Waals complexes with Ar and H2O , 1996 .

[30]  P. Barbara,et al.  Electron-transfer times are not equal to longitudinal relaxation times in polar aprotic solvents , 1987 .

[31]  G. Köhler,et al.  Two-State Model for the Photophysics of 9,9‘-Bianthryl. Fluorescence, Transient-Absorption, and Semiempirical Studies† , 1998 .

[32]  O. Kajimoto,et al.  9,9′-Bianthryl and its van der Waals complexes studied by rotational coherence spectroscopy: Structure and excited state dynamics , 2000 .