TY - JOUR
T1 - UV-visible absorption study of the selfassociation of non-ionic chromonic triphenylenes TP6EOnM (n = 2, 3, 4) in dilute aqueous solutions
T2 - Impact of chain length on aggregation
AU - Herbaut, Antoine
AU - Baranoff, Etienne
PY - 2015/9/1
Y1 - 2015/9/1
N2 - A series of triphenylenes with oligoethoxy chains of various length, TP6EOnM with n = 2, 3, 4, has been synthesised and purified by HPLC. The self-association of these disc-shaped molecules in dilute aqueous solutions (~10-7 to ~4 × 10-4 M) has been studied by UV-visible absorption spectroscopy. The free energy of association decreases as the length of the chains increases. As a result, for a given concentration, the average size of aggregate diminishes as the chain length increases. While the absorption properties of the monomer are identical for the three molecules, the extinction coefficients of solutions of the three triphenylenes at a given concentration are significantly different and are directly linked to the average size of the aggregates. The change of epsilon values upon aggregation could explain the trend generally observed with dyes for solar cells substituted with chains of increasing length showing increasing extinction coefficient values.
AB - A series of triphenylenes with oligoethoxy chains of various length, TP6EOnM with n = 2, 3, 4, has been synthesised and purified by HPLC. The self-association of these disc-shaped molecules in dilute aqueous solutions (~10-7 to ~4 × 10-4 M) has been studied by UV-visible absorption spectroscopy. The free energy of association decreases as the length of the chains increases. As a result, for a given concentration, the average size of aggregate diminishes as the chain length increases. While the absorption properties of the monomer are identical for the three molecules, the extinction coefficients of solutions of the three triphenylenes at a given concentration are significantly different and are directly linked to the average size of the aggregates. The change of epsilon values upon aggregation could explain the trend generally observed with dyes for solar cells substituted with chains of increasing length showing increasing extinction coefficient values.
KW - Aggregation
KW - Self-association
KW - TP6EO2M
KW - Triphenylene
KW - UV-visible absorption
UR - http://www.scopus.com/inward/record.url?scp=84944043213&partnerID=8YFLogxK
U2 - 10.2533/chimia.2015.520
DO - 10.2533/chimia.2015.520
M3 - Article
AN - SCOPUS:84944043213
SN - 0009-4293
VL - 69
SP - 520
EP - 523
JO - CHIMIA International Journal for Chemistry
JF - CHIMIA International Journal for Chemistry
IS - 9
ER -