THF/water mixtures where aggregation takes place, g lum factors remain of the same
order of magnitude.
Finally, the Lacour’s group was able to prepare NMI-5 and observe excimer CPL
with g lum ~|8 Â 10
À3 | (Fig. 12.9), to be compared with a g abs ~|2.6 Â 10
À4 |. In this
compound, the donor group on the NMI moieties is attached at position 3 of the
naphthalene subunit (and not 4 as it is usually the case), and this heteroatom serves as
a linker to the 18C6-scaffold [28].
R-NMI-1
S-NMI-1
O
O
O
O
N
N
O
O
O
O
n
n
n = 1
n = 3
NMI-1
NMI-2
Cheng 2015
N
N
O
O
O
O
Cheng 2016
R
R
R = H
R = CH 3 O
NMI-3
NMI-4
Fig. 12.8 1,8-Naphthalene monoimide derivatives developed by Cheng et al. CPL spectra of
NMI-1 (THF, C ¼ 10
À5 M). Adapted with permission from reference [35]
O
O
O
O
O
O
O
O
O
H
H
HN
NH
PrN
O
O
NPr
O
O
NMI-5
Lacour 2018
Fig. 12.9 NMI-functionalized 18C6-macrocycle and CPL spectra recorded in CH 3 CN,
C ¼ 10
À5 M. Adapted from reference [28]. Published by The Royal Society of Chemistry
12 Circularly Polarized Luminescence from Intramolecular Excimers
289