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Fluorescence switching with subphthalocyanine-dihydroazulene dyads

Henrik Gotfredsen, Martin Drøhse Kilde, Marco Santella, Anders Kadziola and Mogens Brøndsted Nielsen*

Department of Chemistry, University of Copenhagen, Universitetsparken 5,

DK-2100 Copenhagen Ø, Denmark. E-mail: mbn@chem.ku.dk

Electronic supporting information

Table of Contents

NMR Spectra ........................................................................................................................2

Selected Crystallographic Data ............................................................................................4

UV-Vis Absorption Spectra ...................................................................................................5

Fluorescence Quantum Yields..............................................................................................6

Switching Studies .................................................................................................................8

References .........................................................................................................................10

Electronic Supplementary Material (ESI) for Molecular Systems Design & Engineering.This journal is © The Royal Society of Chemistry 2019

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NMR Spectra

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.010.511.0ppm

3.91

0.95

1.00

2.011.051.09

1.03

1.79

2.06

6.14

6.01

1.621.631.641.651.681.691.70

3.803.803.813.813.81

5.835.835.855.856.306.306.316.326.326.326.336.346.356.366.466.486.496.506.566.576.586.596.88

7.217.23

7.577.597.877.887.887.89

8.828.828.838.83

Figure S1. 1H-NMR (500 MHz) spectrum of 3 recorded in CDCl3.

0102030405060708090100110120130140150160170180ppm

22.20

45.19

51.32

58.00

80.53

89.95

112.82

115.26

119.66

121.29

122.24

125.59

125.96

127.84

129.33

129.88

131.06

131.13

132.41

132.57

138.81

139.81

151.68

N

N N

NN

N

B

O

NCCN

N

N N

NN

N

B

O

NCCN

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Figure S2. 13C-NMR (126 MHz) spectrum of 3 recorded in CDCl3.

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.010.511.0ppm

9.29

0.99

2.04

1.01

1.051.001.031.062.071.00

2.202.144.141.14

5.08

0.94

1.08

3.803.813.813.813.825.315.335.825.835.845.856.296.306.316.316.326.356.366.446.456.456.466.476.476.486.526.536.536.546.556.556.566.766.786.957.707.727.777.797.907.907.917.928.018.028.038.038.818.818.838.848.848.848.858.858.858.869.05

7.77.87.98.08.18.88.99.09.1 5.35.45.85.96.36.46.56.66.76.86.97.0

1

Figure S3. 1H-NMR (500 MHz) spectrum of 6 recorded in CDCl3.

0102030405060708090100110120130140150160170180ppm

31.46

33.98

45.19

51.27

91.50

92.42

112.75

115.17

117.85

119.64

121.71

122.29

122.38

122.45

124.31

124.74

125.86

125.91

126.37

127.87

130.00

130.09

130.19

130.21

130.58

130.94

130.98

130.99

131.13

131.17

131.30

131.34

132.58

132.63

133.24

138.62

139.45

143.81

150.14

150.65

150.66

151.81

151.82

152.39

Figure S4. 13C-NMR (126 MHz) spectrum of 6 recorded in CDCl3.

N

N N

NN

N

B

O

NCCN

N

N N

NN

N

B

O

NCCN

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Selected Crystallographic Data

CCDC 1861766Empirical formula C46H27BN8O Formula weight 718.57 Temperature/K 122(2) Space group P-1 a/Å 10.374(14) b/Å 12.619(14) c/Å 15.496(17) α/° 71.92(6) β/° 80.91(5) γ/° 71.19(4) Volume/Å3 1822(4) Z 2 ρcalcg/cm3 1.310 μ/mm-1 0.081 F(000) 744.0 Radiation MoKα (λ = 0.71073) 2Θ range for data collection/° 4.62 to 50.7 Index ranges -12 ≤ h ≤ 12, -14 ≤ k ≤ 15, -18 ≤ l ≤ 18 Reflections collected 47387 Independent reflections 6522 [Rint = 0.0359] Data/restraints/parameters 6522/0/505 Goodness-of-fit on F2 1.023 Final R indexes [I>=2σ (I)] R1 = 0.0760, wR2 = 0.2092 Final R indexes [all data] R1 = 0.0943, wR2 = 0.2286 Largest diff. peak/hole / e Å-3 1.26/-0.45

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UV-Vis Absorption Spectra

Figure S5. UV-Vis absorption spectrum of 3 recorded in toluene.

Figure S6. UV-Vis absorption spectrum of 6 recorded in toluene.

N

N N

NN

N

B

O

NCCN

N

N N

NN

N

B

O

NCCN

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Fluorescence Quantum Yields

Fluorescence quantum yields (QYs) were measured by multipoint determination using a Cary 300

UV-Vis spectrophotometer for absorption measurements and a Fluotime 300 (PicoQuant)

instrument for fluorescence measurements. Cresyl violet perchlorate in absolute ethanol was used

as reference dye.1

The quantum yields (ФF) were determined using the relative method according to the following

formula.2

Φ𝐹=Φ𝐹,𝑟𝑒𝑓𝛼 ∙ 𝑛2

𝛼𝑟𝑒𝑓 ∙ 𝑛2𝑟𝑒𝑓

The subscript ref designates the reference dye (cresyl violet perchlorate or CVP, ФF,ref = 0.56 in

ethanol), the refractive index of the solvent and the slope obtained from a linear-fit to a set of 𝑛 𝛼

data points (Iint vs. fa). Here Iint refers to the integrated emission intensity and fa to the fraction of

absorbed light (fa = 1-10-A, A being the absorbance measured at the wavelength of excitation, 507

nm). For all QY determinations five or more data points were collected with a measured

absorbance below 0.1 for the longest wavelength absorption.

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Figure S7. Fraction of absorbed light for CVP (reference dye, left) in EtOH and compound 3 (right)

in toluene at different concentrations.

Figure S8. Emission spectra (excitation at 507 nm) of CVP (reference dye, left) in EtOH and 3

(right) in toluene at different concentrations.

Figure S9. Linear-fit of data points (Iint vs fa) for CVP (left) and 3 (right).

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Switching Studies

Figure S10. Left: Change in absorption spectra upon converting 3-DHA to 3-VHF in toluene by

irradiation at 420 nm. Right: Change in absorption spectra upon thermal conversion of 3-VHF to 3-DHA in toluene at 25 oC.

Figure S11. Left: Change in absorption spectra upon converting 6-DHA to 6-VHF in toluene by

irradiation at 420 nm. Right: Change in absorption spectra upon thermal conversion of 6-VHF to 6-DHA in toluene at 25 oC. The conversions do not occur with isosbestic points due to degradation.

A sample of a pure photochromic SubPc-DHA was dissolved in toluene. This stock solution was

kept in the dark at all times. A sample of the stock solution was placed in the cuvette, and a

spectrum was acquired (25 ºC). The sample was then irradiated at 420 nm for a short while

(seconds to minutes for 3 and minutes to hours for 6), then a spectrum was acquired (UV-Vis or

fluorescence). This procedure was repeated until no change in the spectrum could be seen, going

from SubPc-DHA to SubPc-VHF (for 6 this was repeated until what seemed to be degradation of

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the system instead of conversion from 6-DHA to 6-VHF). When fully converted, the SubPc-VHF to

SubPc-DHA back-reaction was monitored at 25 οC by acquiring a UV-Vis absorption spectrum over

more than one half-live. The conversion of 3-DHA to 3-VHF occurred with isosbestic points in the

absorption spectra and also from 3-VHF to 3-DHA (see Figure 4 in article). The decay of

absorption at 460 nm of the SubPc-VHF-species was plotted against time. The exponential decay

of the SubPc-VHF absorbance was subjected to curve fitting (first-order kinetics), from which the

rate constant k25ο

C (SubPc-VHF to SubPc-DHA) was determined (Figures S12 and S13).

Figure S12. Decay in absorbance of 3-VHF at 460 nm in time at 25 oC in toluene.

Figure S13. Decay in absorbance of 6-VHF (plus degradation products) at 460 nm in time at 25 oC

in toluene.

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References

1. R. Sems and K. H. Drexhage, J. Lumin., 1981, 24-25, 709-712.

2. C. Würt, M. Grabolle, J. Pauli, M. Spieles and U. Resch-Genger, Nat. Protoc., 2013, 8, 1535-

1550.