Communication: Manipulating the singlet-triplet equilibrium in organic biradical materials.
We investigated the tunability of the singlet-triplet equilibrium population in the organic biradical 1,4-phenylenedinitrene via magneto-optical spectroscopy. A rich magnetochromic response occurs because applied field increases the concentration of the triplet state species, which has a unique optical signature by comparison with the singlet biradical and the precursor molecule. A Curie-like analysis of the magneto-optical properties allows us to extract the spin gap, which is smaller than previously supposed. These measurements establish the value of local-probe photophysical techniques for magnetic property determination in open-shell systems such as biradicals where a traditional electron paramagnetic resonance Curie law analysis has intrinsic limitations.
Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
O
O
Günaydın-Sen
J
J
Fosso-Tande
P
P
Chen
J L
JL
White
T L
TL
Allen
J
J
Cherian
T
T
Tokumoto
P M
PM
Lahti
S
S
McGill
R J
RJ
Harrison
J L
JL
Musfeldt