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.
Departamento de Química Física, Universidad de Málaga, 29071-Málaga, Spain. casado@uma.es
Juan
J
Casado
Kazuo
K
Takimiya
Tetsuo
T
Otsubo
Francisco J
FJ
Ramírez
J Joaquín
JJ
Quirante
Rocío
R
Ponce Ortiz
Sandra R
SR
González
María
M
Moreno Oliva
Juan T
JT
López Navarrete