providing a strong green fluorescence emission. The proportion of H- and
J-aggregations modes within supramolecular gels controlled by the temperature
determines the mechanical and the fluorescent properties (Fig. 4.18). By increasing
temperature, partial H-aggregates change to J-aggregate modes due to enhanced
movement of encapsulated solvent molecules in the gel, leading to green
Si O
OH
Si
O
OH
NH 2 (CH 2 ) 3 Si(OEt) 3
Si O
O
Si
O
O
Si
H 2 N
NH 2
NH 2
NH 2
H 2 N
N
N
O
O
OHC
CHO
Mn
Cl
DMSO, 80
Si O
O
Si
O
O
Si
N
50
61
(61)
(50)
(61)
(50)
(61)
Mn-salen
imine gel layer
Fig. 4.16 Schematic representation of coating of Mn-salen imine gel on the wall of fused-silica
capillary, and SEM images of a cross section of the capillary coated with Mn-salen gel prepared
from 50 and 61 with about 2 lm thickness. Reproduced with permission from [49]. Copyright ©
The Royal Society of Chemistry 2015
146
4 Dynamic Covalent Gels