Supporting Information
Charge Transfer Liquid: A Stable Donor-Acceptor
Interaction in Solvent-free Liquid State
Vivek C. Wakchaure,a,b
Lekshmi V. Pillai,c
Goudappagouda,a,b
Kayaramkodath
C. Ranjeesh,a,b
Suman Chakrabarty,d Sapna Ravindranathan,
b,e Pattuparambil R.
Rajamohanan,b,e
Sukumaran S. Babu*a,b
a. Organic Chemistry Division, National Chemical Laboratory (CSIR-NCL), Dr. Homi
Bhabha Road, Pune-411008, India. b.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201 002, India. c. Amrita Vishwa Vidyapeetham University, Amritapuri, Kerala-690525, India.
d. S. N. Bose National Centre for Basic Sciences, JD Block, Sector-III, Salt Lake City,
Kolkata - 700 106, India e. Central NMR Facility, National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha
Road, Pune-411008, India.
Content
1. Experimental Page S2
2. Synthesis Page S5
3. Figures S1 to S21 Page S10
4. References Page S23
Electronic Supplementary Material (ESI) for ChemComm.This journal is © The Royal Society of Chemistry 2019
S-2
Experimental
Materials
All chemicals, 12-tricosanone, 1-bromo-2-ethylhexane, 1,8-naphthalic anhydride,
naphthalene-1,4,5,8-tetracarboxylic dianhydride (TCI), 2-ethylhexyl amine, ammonium
acetate (Spectrochem), sodium cyanoborohydride, dithranol (Aldrich), 2,6-
dihydroxynaphthalene (Alfa Aeser) and hydrochloric acid (Spectrochem) were used as
received. The solvents such as dichloromethane, methanol, dimethylformamide (Finar) were
used as received without further purification. Thin layer chromatography was carried out
using Aluchrosep Silica Gel 60/UV254 purchased from Merck Specialities Pvt Ltd and
visualized either by UV Fluorescence or by iodine chamber. Column chromatography was
performed using silica gel (100-200 mesh), bed was made by using 60-120 mesh silica
purchased from Spectrochem Pvt. Ltd. India and mixtures of dichloromethane-PET used for
elution were distilled before use.
General
All the reactions were carried out in oven dried round bottom flasks under argon atmosphere
unless otherwise mentioned. The 1H,
13C NMR spectra were recorded on a Bruker-400 MHz
NMR spectrometer. NOESY and ROESY NMR experiments were carried out on a Bruker
700 MHz spectrometer while diffusion experiments were carried out on a Bruker 500 MHz
spectrometer equipped with a broad band diffusion probe (DIFF60) generating a maximum
gradient of 1700 Gauss/cm. The chemical shift values for 1H (TMS as internal standard) and
13C NMR are recorded in CDCl3. The value of coupling constant (J) is stated in Hertz (Hz).
MALDI-TOF MS spectrum was recorded using dithranol as the inert matrix on AB SCIEX
MALDI TOF/TOF™ 5800. FT-IR spectra were recorded using Bruker Alpha FT-IR
spectrometer and reported in frequency of absorption (cm-1
). UV-Vis absorption spectra were
recorded with a Shimadzu 1800 spectrophotometer, while all emission spectra were
performed using PTI Quanta Master™ Steady State Spectrofluorometer. The Powder X-ray
diffraction patterns were recorded on a Rigaku, MicroMax-007HF equipped with high
intensity Micro focus rotating anode X-ray generator. The data was collected with the help of
Control Win software. A Rigaku, R-axis IV++ detector was used for the wide-angle
experiments using Cu K (1.54 Å) radiation outfitted with a Ni filter and Aluminium holder
was used as sample holder. DSC Q 10 differential scanning calorimeter connected to Q Series
S-3
PCA (TA Instruments, USA) was used to determine the phase transition temperatures of
molecule. TGA data was collected in METTLER TOLEDO, TGA/SDTA851 instrument.
Rheology experiment was carried out using a MCR dynamic oscillatory Cup and Bob
Frequency Sweep at 20 oC by using about 5 g of the liquid samples.
Preparation of liquid CT complex
The donor 1 and acceptor 2 with different equivalents in glass vials (1.5 mL) were either
stirred well with spatula or heated gently to become a homogeneous mixture.
UV-VIS spectrum of neat liquids
UV-Vis spectra of all neat liquids were recorded in the transmittance mode and the samples
are prepared by making a uniform transparent coating of 5 mg sample on 1 x 1 cm2 area of
quartz plate. The consistency of each spectrum was confirmed by repeated trails.
NMR experiments
NMR spectra in n-hexane were recorded using DMSO-d6 as the external reference. All the
NMR spectra in the neat condition (1, 2 and 1+2 CT liquids) were recorded by placing the
compounds (~ 200 mg) in a 3 mm NMR tube and inserting it in an outer 5 mm NMR tube
containing DMSO-d6 as an external lock. After mixing, samples were allowed to homogenize
at the measurement temperature before carrying out the experiments. The actual ratios of 1
and 2 were estimated by integration of peak areas of the aromatic protons.
Molecular dynamics (md) simulations
All MD simulations were performed using Gromacs 5.0.7 software. Molecule 3 with short
branched alkyl chain has been chosen for facile MD simulations. The GAFF force field
parameters for compound 1 and 3 were generated using the antechamber utility of
AmberTools 18. A cubic simulation box containing 10 acceptor and 100 donor molecules
(D:A = 1:0.1) was prepared with periodic boundary conditions. The system was energy
minimized using steepest descent algorithm. All the systems were equilibrated for 2 ns in
NPT ensemble using a velocity rescale thermostat and Parrinello-Rahman barostat at 300 K
and 1 bar. Long-range electrostatic interactions were calculated with the particle mesh Ewald
(PME) summation method with a grid spacing of 0.16 nm and fourth-order cubic
interpolation. For short range electrostatics and van der Waals interaction, a cut-off distance
of 1 nm was used. The integration time step was set to 2 fs. The production run was further
continued for 100 ns and coordinates were saved every 20 ps for further analysis. Radial
distribution functions (RDF) captures the statistical distribution of the distance between
chosen pairs.
S-4
Synthesis
Molecules1 and 2 are synthesized as shown in Scheme S1.
Scheme S1. Synthesis of 1and 2.
Procedure for synthesis of 2,6-bis((2-ethylhexyl)oxy)naphthaleneS1
Potassium carbonate 8.6 g (5 eq.) was suspended in 50 ml of acetonitrile and sonicated for 30
min followed by degassing N2 for 30 minutes. 12 g (5 eq.) of 2-ethylhexyl bromide was
added into above reaction mixture. Separately 2 g (1 eq.) of 1,5-dihydroxynaphthalene
suspended in acetonitrile and added via a dropping funnel to the reaction mixture. After
completion of addition, the reaction mixture was refluxed under N2 for 24 h. The progress of
reaction was monitored by TLC. After completion of reaction, the reaction mixture was
filtered, the filtrate collected and solvent removed under reduced pressure. The residue
obtained was dissolved in chloroform and washed with 1M hydrochloric acid, water and
brine. The organic layer was dried over sodium sulphate and the solvent was removed under
reduced pressure. The crude product was purified by silica gel column chromatography by
using 10% dichloromethane in petroleum ether as an eluent (Rf = 0.8). Combined organic
layer was concentrated under reduced pressure and dried under vacuo to yield a colourless
liquid (3.94 g, 82%).
S-5
1H-NMR (400 MHz, CDCl3, 25
oC): δ = 7.63 (2H, d, J = 8.7 Hz), 7.14-7.12 (2H, dd, J = 8.7
and 2.26 Hz), 7.10 (2H, d, J = 2.26 Hz), 3.95-3.93 (4H, m), 1.79 (2H, m), 1.55-1.38 (8H, m),
1.37-1.34 (8H, m), 0.98-0.91 (12H, m) ppm.
13C-NMR (100 MHz, CDCl3, 25
oC): δ = 155.76, 129.66, 127.91, 119.24, 106.88, 70.55,
39.41, 30.60, 29.11, 23.94, 23.06, 22.9, 14.09, 11.14 ppm.
MALDI-TOF MS: calcd. for C26H40O2 = 384.6040, found 384.2239.
Tricosan-12-amineS2
1,2-Tricosanone, ammonium acetate (NH4OAc) and sodium cyanoborohydride (NaBH3CN)
were dissolved in 40 ml methanol (HPLC grade) and stirred at RT for 56 h (3 days). After a
clear solution was observed in the reaction mixture, it was quenched by adding conc.
hydrochloric acid dropwise. The solution was then concentrated with rotatory evaporator.
The solid thus obtained was dispersed in 250 ml of water and adjusted to pH = 10 with KOH.
The obtained latex solution was extracted by using 150 ml of dichloromethane two times.
Combined organic layer was dried over sodium sulphate and the solvent was removed under
reduced pressure to give pale yellow liquid in quantitative yield. The amine obtained was
used further without purification.
2,7-di(tricosan-12-yl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraoneS3
Naphthalene-1,4,5,8-tetracarboxylic dianhydride (200 mg, 1 eq.) and tricosan-12-amine (633
mg, 2.5 eq.) were suspended in DMF (20 mL) in 100 ml round bottom flask. The reaction
mixture was stirred for 6 h at 140°C. The progress of reaction was monitored by TLC. After
completion of reaction, the reaction mixture was allowed to cool to RT and it was quenched
by addition of hydrochloric acid (2N, 40 mL). Reaction mixture was extracted with
dichloromethane (3 × 200 mL). The organic layer was dried over sodium sulphate and the
solvent was removed under reduced pressure. The crude product was purified by silica gel
S-6
column chromatography by using 50% dichloromethane in petroleum ether as an eluent (Rf =
0.6). Combined organic layer was concentrated under reduced pressure and dried under vacuo
to yield a light brown colour solid (584 mg, 86%).
1H-NMR (500 MHz, CDCl3, 25
oC): δ = 8.73 (4H, s), 5.21-5.12 (2H, m), 2.24-2.17 (4H, m),
1.87-1.78 (4H, m), 1.33-1.19 (72H, m), 0.85 (12H, t, J = 6.8 Hz) ppm.
13C-NMR (125 MHz, CDCl3, 25
oC): δ = 164.1, 162.9, 131.3, 130.6, 126.8, 55.2, 32.3, 31.9,
29.6, 29.5, 29.3, 26.9, 22.7, 14.1 ppm.
MALDI-TOF MS: calcd. for C60H98N2O4 = 911.4540, found 911.5922.
1H NMR spectra of 2,6-bis((2-ethylhexyl)oxy)naphthalene 1.
VW_Dye_01022019.001.001.1r.esp
7.7 7.6 7.5 7.4 7.3 7.2 7.1 7.0
Chemical Shif t (ppm)
2.012.032.04
7.1
07
.10
7.1
2
7.1
37
.14
7.2
7
7.6
17
.63
VW_Dye_01022019.001.001.1r.esp
7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
Chemical Shif t (ppm)
12.258.308.102.054.072.012.032.04
0.9
10
.92
0.9
60
.98
1.3
41
.35
1.3
51
.37
1.4
71
.56
1.5
91
.78
1.7
91
.80
3.9
33
.94
3.9
43
.95
7.1
07
.10
7.1
27
.27
7.6
17
.63
S-7
13
C NMR spectra of 2,6-bis((2-ethylhexyl)oxy)naphthalene 1.
MALDI-TOF MS of 2,6-bis((2-ethylhexyl)oxy)naphthalene 1.
13C.jdf
180 160 140 120 100 80 60 40 20 0
Chemical Shif t (ppm)
CHLOROFORM-d
11
.14
14
.09
23
.06
23
.94
29
.11
30
.60
39
.41
70
.55
77
.00
10
6.8
8
11
9.2
4
12
7.9
11
29.6
6
15
5.7
6
S-8
1H NMR spectra of naphthalene-1,4,5,8-tetracarboxylic dianhydride 2.
13
C NMR spectra of naphthalene-1,4,5,8-tetracarboxylic dianhydride 2.
Tue3av2#183_11682.001.001.1r.esp
9 8 7 6 5 4 3 2 1 0
Chemical Shif t (ppm)
12.0472.044.024.022.003.96
0.0
00.8
20
.85
0.8
8
1.1
91
.25
1.5
91
.78
1.8
11
.85
1.8
72
.17
2.1
92
.21
2.2
4
5.1
15
.13
5.1
65
.18
5.2
07.2
7
8.7
3
Tue3av2#183_11682.001.001.1r.esp
9.0 8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0
Chemical Shif t (ppm)
2.003.96
5.1
25
.135
.16
5.1
95
.21
7.2
7
8.7
3
13C.001.1r.esp
180 160 140 120 100 80 60 40 20 0
Chemical Shif t (ppm)
CHLOROFORM-d
14
.09
22
.65
26
.88
29
.29
29
.53
29
.57
31
.88
32
.27
55
.16
77
.00
12
6.3
11
26.7
9
13
0.6
11
31.3
4
16
2.9
81
64.1
3
S-9
MALDI-TOF MS of naphthalene-1,4,5,8-tetracarboxylic dianhydride 2.
Synthesis and characterization of molecules 3S3
, 4S4
, and 5S5
are conducted according to the
reported procedures.
S-10
Figures
Figure S1. a) absorption and b) steady state emission spectra of 1 and 2 in dichloromethane
solution and in neat thin film (λex = 342 nm for 1 and 353 nm for 2). Inset of Figure S1-b
shows the photograph of 1 under UV light (365 nm). c, d) DSC thermograms in the heating
trace at a scanning rate of 10 ˚C/min and e, f) TGA of 1 and 2, respectively.
Absorption spectra show that both the compounds absorb in the range of 300 to 400 nm
(Figure S1-a) and there is no absorption peak between 400 to 600 nm for both the molecules.
Both 1 and 2 exhibits almost similar absorption features in solution and thin film. Compound
1 shows an enhanced deep blue emission ranging from 350 to 450 nm with λmax located at
372 nm (Figure S1-b). NDI derivative 2 exhibited a comparatively broad emission from 370
to 550 nm, which is nearly 30 nm red shifted to that of 1. However, in the neat form only
compound 1 is found to be emissive (Inset; Figure S1-b).
400 500 600
In
ten
sit
y (
No
rm)
Wavelength (nm)
1 sol
1 Thin film
2 sol
300 400 500
A
bso
rban
ce (
No
rm)
Wavelength (nm)
1 sol
1 Thin film
2 sol
2 Thin film
100 200 300 400 500
0
50
100
50% at 303 oC
Wt
loss / %
Temperature (oC)
1
5% at 234 oC
100 200 300 400 500
0
50
100
Wt
los
s / %
Temperature (oC)
2
5% at 281 oC
50% at 421 oC
-50 0 50 100
-2
0
2
En
do
the
rmic
Temperature (oC)
Cooling
1
-60.1 oC
Heating
c)
e)
-100 -50 0 50 100 150-4
-2
0
2
4
Temperature (oC)
2-15.68
oC
9.62 oC
46.84 oC
Cooling
HeatingEn
do
therm
ic
d)
f)
a) b)
S-11
Figure S2. a) Variation of storage modulus (Gʹ) (■), loss modulus (Gʺ) () and complex
viscosity (ŋ*) (■) versus angular frequency on double logarithmic scale, of 1. b) Comparison
of PXRD pattern of 1 and 2.
We prepared a series of acceptor molecules (even donor and acceptor with same branched
alkyl chain) and except molecules 2, none found as RT liquid. Molecule 2 with long branched
chain is a low melting solid giving diffraction peaks in PXRD at RT, not a free flowing liquid.
However, we found that 2 is a free flowing liquid above 46 oC.
Figure S3. a) Variation in absorption spectra of 1 in n-hexane (25 mM) with increasing
equivalents of 2 in n-hexane at 25 ˚C, b) corresponding variation of absorbance at 497 nm
with increasing equivalents of 2. c) Photographs of the CT complex with varying equivalents
(0 to 3) of acceptor 2.
0 10 20 30 40 50
Inte
nsit
y
2
2 (degree)
1
10 10010
-2
100
102
*
(Pa.s
)
G,
G'' (
Pa)
(rad s-1)
G'
G''
a) b)
0 1 2 3
0.0
0.5
1.0
1.5
Ab
so
rba
nc
e a
t 4
97
nm
Equivalents of 2450 500 550 600 650
0.0
0.5
1.0
1.5 0.0
0.2
0.4
0.6
0.8
1.0
1.5
2.0
2.5
3.0
Ab
so
rban
ce
Wavelength (nm)
0 0.2 0.4 0.6 0.8 1.0 1.5 2.0 2.5 3.0
a)
c)
b)
S-12
Figure S4. a) Variation in absorption spectra of 1 in dichloromethane (25 mM) with
increasing equivalents of 2 in dichloromethane at 25 ˚C, b) corresponding variation of
absorbance at 497 nm with increasing equivalents of 2. c) Photographs of the CT complex
with varying equivalents (0 to 3) of acceptor 2.
450 500 550 600 650
0.0
0.1
0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.5
2.0
2.5
3.0
Ab
so
rban
ce
Wavelength (nm)
0 0.2 0.4 0.6 0.8 1.0 1.5 2.0 2.5 3.0
0 1 2 3
0.0
0.1
0.2
Ab
so
rba
nc
e a
t 4
97
nm
Equivalents of 2
a)
c)
b)
S-13
Figure S5. Photographs of the 1+2 (1:1) CT complex in various solvents at different
concentrations.
5 mM
10 mM
20 mM
25 mM
Tetr
ahyd
rofu
ran
Dic
hlo
rom
eth
ane
Ch
loro
form
Tolu
en
e
Cyc
loh
exan
e
n-H
exan
e
S-14
Figure S6. a) UV-Vis absorption spectra of 1+2 (1:1) CT complex in various solvents (25
mM) and the corresponding variation of absorbance at λ = 497 nm against refractive index of
the solvents. Photographs of the 1+2 (1:1) CT complex in various solvents (25 mM) showing
the variation of CT complex colour.
A clear decrease in the CT band intensity shows that the complexation is primarily due to
electrostatic interaction between the donor-acceptor. It has to be noted that polar solvents
can efficiently disrupt the electrostatic attraction unlike nonpolar solvents. Hence, n-hexane
and cyclohexane stabilize the CT complex compared to other polar solvents.
450 500 550 600 6500.0
0.5
1.0A
bso
rban
ce
Wavelength (nm)
n-Hexane
Cyclohexane
Toluene
Chloroform
Dichloromethane
Tetrahydrofuran
1.35 1.40 1.45 1.500.0
0.5
1.0
Dichloromethane
ChloroformTetrahydrofuranToluene
n-Hexane
Ab
so
rban
ce a
t 49
7 n
m
Refractive index
Cyclohexane
a) b)
c)
Tetr
ahyd
rofu
ran
Dic
hlo
rom
eth
ane
Ch
loro
form
Tolu
en
e
Cyc
loh
exan
e
n-H
exan
e
S-15
Figure S7. Absorption spectral variation of 1+2 CT liquid with increasing equivalents of 2
ranging from a) 1:0.0 to 1:0.01, b) 1:0.02 to 1:0.1 and c) 1:0.2 to 1:1.0 in the solvent-free
condition. d) Relative variation of λmax at 495 nm with respect to neat donor as a function of
acceptor concentration at RT.
420 480 540 600 6600.000
0.027
0.054
1:0.01
1:0.005
1:0.001
1:0.0
Ab
so
rban
ce
Wavelength (nm)450 500 550 600 650
0.0
0.2
0.4
0.6 1:0.1
1:0.09
1:0.08
1:0.07
1:0.06
1:0.05
1:0.04
1:0.03
1:0.02
Ab
so
rban
ce
Wavelength (nm)
450 500 550 600 6500
1
2
3 1:1.0
1:0.9
1:0.8
1:0.7
1:0.6
1:0.5
1:0.4
1:0.3
1:0.2
Ab
so
rba
nce
Wavelength (nm)
a) b)
c) d)
[A], moles/Kg
l4
95
nm
Y = b*K*x / (1+k*x)
K = 2.024 0.20 Ml-1
b = 1.48 0.08
S-16
Figure S8. a) Absorption spectral variation of 1+2 CT liquids with increasing equivalents of
2 ranging from 0.0002 to 0.001 equivalents and b) corresponding photographs of CT liquids
of 1 and 2.
Figure S9. DSC thermograms in the heating trace of 1+2 CT liquids with varying equivalents
of 2 at a scanning rate of 10 ˚C/min.
450 500 550 600 6500.00
0.01
0.02
0.03 0.001
0.0005
0.00033
0.00025
0.0002
0.0A
bso
rban
ce
Wavelength (nm)
1:0.001 1:0.0005 1:0.00033 1:0.00025 1:0.0002 0:0
a)
b)
1:0.1
1:0.25
1:0.5
1:0.75
25 50 75 100
Exo
therm
ic
Temperature (oC)
1:1
S-17
Figure S10. DSC thermograms of 1+2 CT liquid with varying acceptor ratio, a) 1:0.1 and b)
1:0.25 at a scanning rate of 10 ˚C/min.
-50 0 50 100-2
0
2
37.9 oC
1:1 (1:0.25)11.8
oC
Temperature (oC)
En
do
the
rmic
-50 0 50 100
-2
0
2
4
-60.3 oC
0.7 oC 1:2 (1:0.1)
30.5 oC
Temperature (oC)
En
do
therm
ic
b)
a)
S-18
Figure S11. DSC thermograms of 1+2 CT liquid with varying acceptor ratio, a) 1:0.5, b)
1:0.75 and c) 1:1 at a scanning rate of 10 ˚C/min.
0 20 40 60 80 100
0
2
47.4 oC
Cooling
1:1
Heating
22.4 oC
En
do
the
rmic
Temperature (oC)
0 20 40 60 80 100
-2
0
2
44.9 oC
Cooling
1:0.75
Heating
20.2 oC
En
do
the
rmic
Temperature (oC)
0 20 40 60 80 100
-4
-2
0
2
4
42.2 oC
Cooling
1:0.5
Heating
17.9 oC
En
do
the
rmic
Temperature (oC)
a)
b)
c)
S-19
Figure S12. TGA analysis of 1, 2 and 1+2 (1:1) CT liquid.
Figure S13. Photographs of the 1+2 CT liquids with varying D-A ratio stored at three
different temperatures, a) -20 ˚C (freezer), b) 30 ˚C (RT) and c) 90 ˚C (oven) for two months.
100 200 300 400 500
0
50
100
Wt
los
s (
%)
Temperature (oC)
1
2
1+2 (1:1)
5% Wt loss
1 234 oC
2 281 oC
1+2 256 oC
-20 oC
30 oC
90 oC
1:0.001 1:0.01 1:1
S-20
Figure S14. a) Photograph of the 3 mm NMR tube containing 1+2 CT liquid inside the 5 mm
NMR tube with DMSO-d6 as an external lock used for all NMR studies. b) Comparison of 1H
NMR spectra of 1 as neat and in CDCl3 solution.
Comparison of the 1H NMR spectra of the donor molecule in CDCl3 and in the neat state
(external reference DMSO-d6), show that all signals shift upfield. The proton Ha at 7.63 (2H,
d, J = 8.7 Hz) shift to 6.78 (2H, d, J = 8.9 Hz) and becomes broad compared to spectrum in
CDCl3. The Hb proton showing doublet of doublets at δppm 7.14 with large ortho coupling
8.7 Hz and small meta coupling 2.26 Hz, shifts to 6.35 showing a doublet with coupling
constant 8.9 Hz. Proton Hc which shows a doublet (J = 2.26 Hz) at δppm 7.10 appears as a
broad singlet at δppm 6.26.
DAN.001.001.1r.esp
2.021.982.00
6.26
6.336.35
6.76
6.78
1H.001.001.1r.esp
7.5 7.0 6.5Chemical Shift (ppm)
2.001.991.99
7.10
7.10
7.12
7.13
7.14
7.27
7.61
7.63
1H.001.001.1r.esp
2.001.99
7.10
7.10
7.12
7.127.
137.
14
Neat
In CDCl3
Ha
Hb Hc
b)a)
S-21
Figure S15. Expansion of 1H NMR titration spectra recorded at 318 K, showing donor 1
proton signals in the aromatic region.
Figure S16. NOESY spectrum of the 1+2 (1:0.98) CT liquid at 318 K. Mixing time is 30 ms,
for which spin diffusion effects are minimal.
HcHbHa
1:0.04
1:0.07
1:0.15
1:0.23
1:0.29
1:0.37
1:0.45
1:0.57
1:0.69
1:0.78
1:0.98
1:1.53
1:0.00
S-22
Figure S17. ROESY spectrum of the 1+2 (1:0.98) CT liquid at 318 K. Spin-lock strength and
duration is 2.5 KHz and 100 ms, respectively.
Figure S18. 2D NMR spectra a) NOESY and b) ROESY of 1+2 (1:1) CT complex in n-
hexane (25 mM) at 318 K.
b)a)
S-23
Figure S19. Two Preferred orientations in the D-A complex obtained from MD simulation.
A near perpendicular stacking is more populated/stable in the MD simulation possibly due to
less steric repulsion between the long alkyl chains. In parallel stack, due to repulsion
between the chains stacking may be a bit distorted. Also, the two aromatic rings of donor
need to align above the four rings of acceptor, hence a staggered alignment of the central
axis of the molecules is likely.
Figure S20. a) Temperature dependent absorption spectral changes of the 1+2 (1:1) CT
complex in cyclohexane (3 mM) and b) the corresponding variation of absorbance at 497 nm
with temperature.
450 500 550 600 650
0.00
0.02
0.04
0.06
0.08 40
oC
45 oC
50 oC
55 oC
60 oC
65 oC
70 oC
5 oC
10 oC
15 oC
20 oC
25 oC
30 oC
35 oC
Ab
so
rban
ce
Wavelength (nm)0 20 40 60 80
0.02
0.04
0.06
Ab
so
rba
nc
e a
t 4
97
nm
Temperature oC
a) b)
S-24
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