Satoshi Iwashima

Charge-Carrier Drift Mobility in Perylene Single Crystals

Abstract The electron and hole drift mobilities in highly pure perylene single crystals were measured using a conventional time-of-flight method. Observed values were 0.017 ± 0.001 cm2/V sec for electrons and 0.02 ± 0.003 cm2/V sec for holes at room temperature. The mobilities increased with the temperature between 296°-353°K with an activation energy of 0.20 eV for electrons. Taking a fluctuation of transfer integrals and a stabilization of electron energy due to the excimer-like excess electron state into consideration, the fairly good agreement between the calculated and measured values of mobility has been obtained.

Structure determination by MS, NMR and UV spectra of bromo and nitro derivatives of 1-azabenzanthrone

Abstract 3-Bromo-1-azabenzanthrone and 9-nitro-1-azabenzanthrone have been identified by their mass, 1 H (HH COSY) and 13 C (ADEPT) NMR, and UV spectra. The position of the nitro group has also been confirmed by mass and UV spectra of 9-nitro-1-azabenzanthrone derivatives: two isomers of pyridino-1-azabenzanthrones. The changeable substitution position of the nitro group on 1-azabenzanthrone is speculated as resulting from some kind of solvent effect for an electrophilic reaction.

Spectral Dependence of Fluorescence Lifetime as a Monitor for Purity of Fluoranthene Crystal

Abstract Fluorescence lifetime was successfully used aa a monitor for the purity of solid fluoranthene purified by several different methods; i.e., sublimation in vacuo, zone refining, a newly developed chemical process, and the chemical process followed by zone refining. The spectral response of the lifetime was found to be an appropriate criterion for purity. The chemical process followed by zone refking waa found to be an excellent method for purification of fluoranthene. Furthermore, studies were made on the effect of such impurities as anthracene, carbazole, fluorene, and naphthacene on the lifetime and its spectral dependence.

Sn ← S1 and Tn ← T1 absorption spectra of highly purified chrysene in solution

Abstract Time-resolved S n ← S 1 and T n ← T 1 absorption spectra were observed for highly purified chrysene in THF solution. Formerly assigned to the S 4 ← S 1 band located in the 17200–17600 cm −1 (581-568 nm) region. S n ← S 1 was reassigned to S 6 ← S 1 . The S 4 ← S 1 , S 5 ← S 1 , S 7 ← S 1 and S 8 ← S 1 bands were also observed at 13500 cm −1 (740 nm). 15700 cm −1 (635 nm). 19000 cm −1 (525 nm), and 20400 cm −1 (490 nm), respectively. The relevant molar extinction coefficients were 7100 (S 4 ← S 1 ), 15000 (S 5 ← S 1 ), 14000 (S 6 ← S 1 ), 19000 (S 7 ← S 1 ), and 14000 M −1 cm −1 (S 8 ← S 1 ).

Electrostatic repulsion between localized charges on hetero-atoms in a doubly charged ion and mechanism of ionization and fragmentation. Electron impact mass spectra of benzanthrone, 1-azabenzanthrone, 8-azabenzanthrone and their 3-bromo substituents

Abstract Electron impact mass spectra and ionization efficiency curves of fragment ions were taken for six benzanthrone homologues, i.e., benzanthrone, 1-azabenzanthrone, 8-azabenzanthrone, 3-bromobenzanthrone, 3-bromo-1-azabenzanthrone and 3-bromo-8-azabenzanthrone. The main fragmentation reactions were the elimination of CO and subsequently of HCN from the molecular ion Mi+ (i = 1,2) based on the observation of metastable ions and the value of appearance energies of fragment ions. The intensity of a doubly charged ion [MCOHCN (or C2H2 in benzanthrone)]2+ compared with an ion (MCO)2+ is strong for 8-azabenzanthrones, intermediate for 1-azabenzanthrones and weak for benzanthrones. This fact suggests that positive charges are localized on oxygen, nitrogen or other hetero-atoms immediately after the formation of a doubly charged molecular ion, that they exclude each other because of strong repulsion at short distances, and that this repulsive force promotes the above fragmentation. Approximate values of the first and second ionization potentials were interpreted from the easily achieved emission of non-bonding electrons from heteroatoms in the outer surface of molecules, which is correlated with the results of molecular orbital calculations.

Time Dependence of the Crystallization of Tetrabenzo [a, cd, j, lm]perylene Evaporated Film as a Function of Purity

Abstract The rate of crystallization from the amorphous state of Tetrabenzo[a, cd, j, lm]perylene(TBP) film under various temperature conditions was examined as a function of the purity of the specimen. On the basis of the absorption and fluorescence spectra of TBP film, the rate of crystallization of TBP film evaporated at room temperature was found to be decreased with increasing impurity of the specimen. The rate of crystallization of TBP, with an impurity level of 10−6 mol/mol, was decreased at temperatures below the glass transition temperature (135-140°C), while the crystalline thin film was immediately obtained at temperatures above the glass transition point. On the other hand, crystalline thin films of the purest TBP (10−8 mol/mol impurity contents) prepared by our methods (J. Chem. Soc. Jpn., 1979 (4), 443) could be obtained immediately after sample preparation independent of the substrate temperature.

Time Rsponse of Crystallization of Impurity Controlled Tetrabenzo- [a, cd, j, Im]perylene Film

Abstract Crystals with quantitiative additions of adding quantitatively VEB or iso-VEB to TBP were prepared, and the time response of the absorption and flurescence spectra were examined for their thin firks evaported at room temperature, 100[ddot]C, 130[ddot]C and also 140[ddot]C. The crystallization rate was found to depend no the purity of the specimen and also on the substrate temperature. Furthermore, we confirm that the purity of TBP estimated in our previous paper1 is reasonable, and that the crystallization rate can be used as a new monitor of purity.

GLYCEROL CONDENSATION PRODUCTS OF AMINOANTHRAQUINONES

Glycerol condensation reaction of 2- and 1-aminoanthraquinones was reexamined. 2-Aminoanthraquinone gave phenaleno[3,2-f]quinolin-7-one (10,11-pyridinobenzanthrone), 9H- phenanthro[10,1-gh]quinolin-9-one (4,5-pyridinobenzanthrone) and phenaleno[2,3-g]quinolin-7-one (10,9-pyridinobenzanthrone) besides phenaleno[2,3-f]quinolin-13-one (9,8-pyridinobenzanthrone) hitherto reported. 1-Aminoanthraquinone gave phenaleno[3,2-h]quinolin-13-one (8,9-pyridinobenzanthrone) along with a small amount of phenaleno[2,3-h]quinolin-7-one (11,10-pyridinobenzanthrone), but not 13H-phenanthro[1,10-gh]quinolin-13-one (6,5-pyridinobenzanthrone) as hitherto reported. NMR spectra of these six compounds were assigned and they supported the assigned isomeric structures.