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Bichromophoric behavior of nitrophenyl‐triazene anions: a resonance Raman spectroscopy investigation
Author(s) -
Ando Rômulo A.,
dos Santos Ana P. V.,
Hörner Manfredo,
Santos Paulo S.
Publication year - 2008
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1891
Subject(s) - triazene , delocalized electron , chemistry , raman spectroscopy , resonance raman spectroscopy , photochemistry , moiety , ring (chemistry) , resonance (particle physics) , excited state , electron transfer , stereochemistry , organic chemistry , atomic physics , physics , optics
Highly delocalized molecular frameworks with intense charge transfer transitions, known as push‐pull systems, are of central interest in many areas of chemistry, as is the case of nitrophenyl‐triazene derivatives. The 1,3‐ bis (2‐nitrophenyl)triazene and 1,3‐ bis (4‐nitrophenyl)triazene were investigated by electronic (UV‐Vis) and resonance Raman (RR) spectroscopies. The bichromophoric behavior of 1,3‐ bis (4‐nitrophenyl)triazene anion opens the possibility of tuning with visible radiation, two distinct electronic states. The RR profiles of nitrophenyl‐triazene derivatives clearly show that the first allowed electronic state can be assigned to a charge transfer from the ring π system to the NO 2 moiety ( ca 520 nm), while the second, as a charge transfer from N 3 − to the aromatic ring ( ca 390 nm). In the para ‐substituted derivative, a more efficient electron transfer and a greater energy separation between the two excited states are observed. Copyright © 2008 John Wiley & Sons, Ltd.