Raman spectroscopy shows interchain through space charge delocalization in a mixed valence oligothiophene cation and in its pi-dimeric biradicaloid dication.
The vibrational Raman spectra of a decathiophene are provided in three relevant oxidations states: for the radical cation, its class III mixed valence system and its "frozen, -170 degrees C" class II MV analogue; for the dication, its singlet biradical pi-dimer and its "hot, +70 degrees C" magnetically active triplet excited state. Everything is compatible with interpentathiophene charge delocalization occurring at distances of 4-5 A similar to those found in the crystals of pi-stacked oligothiophenes. This stresses the interest of this spectroscopic tool for the analyses of electronic processes in crystals or in thin films of conjugated organic molecules.
Casado
Juan
J
Departamento de Química Física, Universidad de Málaga, 29071-Málaga, Spain. casado@uma.es
Takimiya
Kazuo
K
Otsubo
Tetsuo
T
Ramírez
Francisco J
FJ
Quirante
J Joaquín
JJ
Ponce Ortiz
Rocío
R
González
Sandra R
SR
Moreno Oliva
María
M
López Navarrete
Juan T
JT