Optical and magnetic properties of the lowest triplet state of pyrido(2,3-b)pyrazine. An example of /sup 3/n. pi. * azanaphthalene

Journal Article · Thu Mar 26 04:00:00 EST 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100291a016· OSTI ID:6802308

Yamauchi, S; Hirota, N

The lowest excited triplet (T/sub 1/) states of pyrido(2,3-b)pyrazine(2,3-b)pyrazine (PP; 1,4,5-triazanaphthalene) in the three kinds of environments have been studied by using various spectroscopic and magnetic resonance techniques. The authors obtained phosphorescence emission and excitation spectra, triplet lifetimes, zero field splittings (zfs), and triplet sublevel properties. From the analysis of the results the authors conclude that T/sub 1/ is /sup 3/n..pi..* in character in a single crystal of durene and in ethanol, but it is /sup 3/..pi pi..* in trifluoroethanol. Observation of the /sup 3/n..pi..* phosphoresence was made for the first time in azanaphthalenes, which provides direct information about /sup 3/n..pi..* azanaphthalene. The 0-0 band and vibronic bands involving a' vibrations are dominant in the phosphorescence spectrum. Large zfs and negative D (identical with -3/2X; -3.1 GHz) were obtained. As for the sublevel properties T/sub z/ is the most active and T/sub x/ is inactive in both radiative and nonradiative processes, whereas T/sub y/ is moderately active in the T/sub 1/ approx...-->.. S/sub 0/ nonradiative decay process. These /sup 3/n..pi..* properties were discussed in comparison with those of /sup 3/..pi pi..* PP and azanaphtalenes and numbern..pi..* azabenzenes. Possible mechanisms to explain the radiative and nonradiative properties are given.

• Research Organization: Kyoto Univ., Japan
• OSTI ID: 6802308
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:7; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AZINES
DATA
ELECTRON SPIN RESONANCE
EMISSION SPECTRA
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
LIFETIME
LUMINESCENCE
MAGNETIC RESONANCE
MULTIPLETS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHORESCENCE
PYRAZINES
RESONANCE
SPECTRA
TRIPLETS