S1

Supporting Information

Tetraphenylethene-Based Tetracationic Dicyclophanes: Synthesis,

Mechanochromic Luminescence, and Photochemical Reaction

Hao Nian,a Aisen Li,b Yawen Li,a Lin Cheng,a Ling Wang,a Weiqing Xu,b and Liping Caoa,*

[a] Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the

Ministry of Education, College of Chemistry and Materials Science, Northwest

University, Xi’an, 710069, P. R. China.

*e-mail: chcaoliping@nwu.edu.cn

[b] State Key Laboratory of Supramolecular Structure and Materials, Institute of

Theorical Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P.

R. China

Table of Contents Pages

General experimental details S2

Synthetic procedures and characterization data S2

X-ray structure determination S11

UV/vis, Fluorescence and PXRD experiments S18

High-pressure experiments S22

Electronic Supplementary Material (ESI) for Chemical Communications.This journal is © The Royal Society of Chemistry 2020

mailto:chcaoliping@nwu.edu.cn

S2

Experimental Procedures

General Experimental Details. Starting materials were purchased from commercial

suppliers were used without further purification. Melting points were recorded by using

a WRS-1A apparatus in open capillary tubes. IR spectra were measured on a

TENSOR27 spectrometer. NMR spectra were recorded on a spectrometer operating at

400 MHz for 1H and 100 MHz for 13C NMR spectra on a Bruker ascend spectrometer.

Mass spectrometry was performed using an Electron Spray Ionization (ESI) on a

Ultimate3000 and a Micromass Quattro II triplequadrupole mass spectrometer using

electrospray ionization with a MassLynx operating system. UV/vis spectra were done

on Agilent Cary-100 spectrometer. Fluorescence spectra were performed by using a

Horiba Fluorolog-3 spectrometer. SEM images were obtained on Hitachi SU8010

microscope. Powder X-ray diffraction (PXRD) experiments were recorded on Bruker

D8 ADVAHCL.

Synthetic Procedures and Characterization Data

NN

N N

NN

N N

NN

N N

NN

N N

Br

Br

a) MeCN, reflux

b) NH4PF6

43 14PF6

4ClTBACl

Compound 1•4PF6-. A 250mL two-necked flask was charged with 4 (180 mg, 0.68

mmol), dry MeCN (100 mL) and the suspension was heated at 85 °C until all of

compound had dissolved. 3 (200 mg, 0.34 mmol) was added to dry MeCN (10 mL).

The suspension was added into reaction in batches and heated to 85 °C for 3 days. The

reaction mixture was then cooled to ambient temperature and collected precipitate. The

precipitate was washed with acetone (3 × 20 mL) to give rise to a colorless solid. To

exchange Br- counterions to PF6- the solid was dissolved in H2O (10 mL), adding excess

amount of NH4PF6 (300 mg) and the mixture was stirred for 12 h. The precipitate was

collected and washed with H2O (3 × 20 mL) to give rise to a white solid (270 mg). The

final powder product was purified by column chromatography, with CH2Cl2:MeCN

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(saturated NH4PF6) = 4:1 mobile phase (yield: 15.1%). M.p. > 300 °C. IR (KBr, cm-1):

3440m, 3167s, 1548s, 1510m, 1184m, 1076m, 842s, 557m. 1H NMR (400 MHz,

CD3CN): 7.76 (s, 8H), 7.66 (s, 8H), 7.30 (s, 4H), 7.23 (d, J = 8.6, 8H), 7.15 (d, J = 8.6,

8H), 5.42 (s, 8H). 13C NMR (100 MHz, MeCN-d3): 144.0, 143.5, 136.4, 135.0, 134.3,

133.3, 133.1, 125.0, 123.6, 122.0, 54.5. ESI-TOF-MS: m/z 547.1491 ([1•4PF6--2PF6-

]2+, calcd. for [C54H44N8P2F12]2+, 547.1481); 316.4462 ([1•4PF6--3PF6-]3+, calcd. for

[C54H44N8PF6]3+, 316.4438); 201.0929 ([1•4PF6--4PF6-]4+, calcd. for [C54H44N8]4+,

201.0917).

Compound 1•4Cl-. 1•4PF6- (100 mg, 0.07 mol) was dissolved in MeCN (5 mL),

adding excess amount of tetrabutylammoium choride hydrate (TBACl, 100 mg) and the

mixture was stirred for 12 h. The precipitate was collected and washed with MeCN (3

× 10 mL) to give rise to a white solid (yield: 65.8%). M.p. > 300 °C. IR (KBr, cm-1):

3386s, 1631m, 1546m, 1188s, 1076m, 802s, 727m, 536m. 1H NMR (400 MHz, D2O):

7.85-7.75 (m, 8H), 7.64 (s, 8H), 7.46 (s, 4H), 7.19 (d, J = 8.8, 8H), 7.15 (d, J = 8.8,

8H), 5.45 (s, 8H). 13C NMR (100 MHz, MeOH-d4): 144.6, 144.3, 135.6, 135.4, 133.9,

133.4, 125.7, 123.7, 122.6, 54.8 (only 10 of the 11 resonances expected were observed).

(ESI-TOF-MS: m/z 437.1462 ([1•4Cl--2Cl-]2+, calcd. for [C54H44N8Cl2-]2+, 437.1528);

279.7752 ([1•4Cl--3Cl-]3+, calcd. for [C54H44N8Cl-]3+, 279.7787); 201.0882 ([1•4Cl--

4Cl-]4+, calcd. for [C54H44N8]4+, 201.0917).

NN

N N

NN

N N

NN

N N

NN

N N

Br

Br

a) MeCN, reflux

b) NH4PF6

53 24PF6

4ClTBACl

Compound 2•4PF6-. A 250 mL two-necked flask was charged with 5 (250 mg, 0.69

mmol), dry MeCN (100 mL) and the suspension was heated at 85 °C until all of

compound had dissolved. 3 (200 mg, 0.34 mmol) was added to dry MeCN (10 mL).

The suspension was added into reaction in batches and heated to 85 °C for 3 days. The

S4

reaction mixture was then cooled to ambient temperature and collected precipitate. The

precipitate was washed with acetone (3 × 20 mL) to give rise to a colorless solid. To

exchange Br- counterions to PF6- the solid was dissolved in H2O (10 mL), adding excess

amount of NH4PF6 (300 mg) and the mixture was stirred for 12h. The precipitate was

collected and washed with H2O (3 × 20 mL) to give rise to a yellow solid (175 mg).

The final powder product was purified by PTLC, with CH2Cl2: MeCN (saturated

NH4PF6) = 3:1 to mobile phase (yield: 17.8%). M.p. > 300 °C. IR (KBr, cm-1): 3437s,

3160s, 1627w, 1546m, 1510m, 1190w, 842s, 557m. 1H NMR (400 MHz, CD3CN): 8.46

(dd, J = 7.0 and 3.2 MHz, 8H), 8.07 (s, 4H), 7.80-7.70 (m, 12H), 6.93 (s, 16H), 6.85 (s,

4H), 6.59 (s, 8H). 13C NMR (100 MHz, DMSO-d6): 142.4, 142.1, 134.9, 133.3, 131.8,

130.5, 127.8, 126.7, 124.9, 124.5, 122.3, 121.2, 45.8. ESI-TOF-MS: m/z 647.1748

([2•4PF6--2PF6-]2+, calcd. for [C70H52N8P2F12]2+, 647.1794); 383.1323 ([2•4PF6--3PF6-

]3+, calcd. for [C70H52N8PF6]3+, 383.1313); 251.1084 ([2•4PF6--4PF6-]4+, calcd. for

[C70H52N8]4+, 251.1073).

Compound 2•4Cl-. 2•4PF6- (100 mg, 0.06 mol) was dissolved in MeCN (5 mL),

adding excess amount of tetrabutylammoium choride hydrate (TBACl, 100 mg) and the

mixture was stirred for 12 h. The precipitate was collected and washed with MeCN (3

× 10 mL) to give rise to a yellow solid (yield: 71.9%). M.p. > 300 °C. IR (KBr, cm-1):

3398s, 3055s, 1624m, 1546s, 1510m, 1190s, 1078m, 802m, 727m, 609m. 1H NMR

(400 MHz, D2O): 8.50-8.40 (m, 8H), 8.13 (s, 4H), 7.84 (s, 4H), 7.76 (dd, J = 6.9 and

3.1 MHz, 8H), 6.95 (d, J = 8.6, 8H), 6.86 (d, J = 8.6, 8H), 6.83 (s, 4H), 6.63 (s, 8H). 13C NMR (100 MHz, CD3OD): 144.5, 143.9, 135.2, 133.7, 132.2, 129.7, 127.8, 126.1,

125.4, 123.6, 123.0, 47.3 (only 10 of the 11 resonances expected were observed). ESI-

TOF-MS: m/z 537.1782 ([2•4Cl--2Cl-]2+, calcd. for [C70H52N8Cl2-]2+, 537.1841); m/z

346.4634 ([2•4Cl--3Cl-]3+, calcd. for [C70H52N8Cl-]3+, 346.4662); m/z 251.1050

([2•4Cl--4Cl-]4+, calcd. for [C70H52N8]4+, 251.1073).

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Figure S1. 1H NMR spectrum recorded (400 MHz, CD3CN, RT) for 1•4PF6-.

Figure S2. 13C NMR spectrum recorded (100 MHz, CD3CN, RT) for 1•4PF6-.

S6

Figure S3. 1H NMR spectrum recorded (400 MHz, D2O, RT) for 1•4Cl-.

Figure S4. 13C NMR spectrum recorded (100 MHz, CD3OD, RT) for 1•4Cl-.

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Figure S5. 1H NMR spectrum recorded (400 MHz, CD3CN, RT) for 2•4PF6-.

Figure S6. 13C NMR spectrum recorded (100 MHz, DMSO-d6, RT) for 2•4PF6-.

S8

Figure S7. 1H NMR spectrum recorded (400 MHz, D2O, RT) for 2•4Cl-.

Figure S8. 13C NMR spectrum recorded (100 MHz, CD3OD, RT) for 2•4Cl-.

S9

Figure S9. Experimental and calculated electrospray ionization mass spectra of

1•4PF6-.

Figure S10. Experimental and calculated electrospray ionization mass spectra of

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1•4Cl-.

Figure S11. Experimental and calculated electrospray ionization mass spectra of

2•4PF6-

S11

Figure S12. Experimental and calculated electrospray ionization mass spectra of

2•4Cl-.

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X-ray Structure determination.

The crystal of 1•4Cl-: Data collections was performed on Bruker VENTURE system

with PHOTON 100 CMOS detector equipped and a Mo-target fine-focus X-ray source

(λ = 0.71073 Å) and graphite monochromator. The data was collected at 114 K crystal

temperature (Oxford Cryosystems CRYOSTREAM 700), 50 kV and 30 mA with an

appropriate 0.5° ω and φ scan strategy. Data reduction and integration were performed

with SAINT (version 8.38A).1 Data was corrected for absorption effects using the

empirical methods as implemented in SADABS (version 2016/2).2 The structure was

solved by SHELXT (version 2018/2)3 and refined by full-matrix least-squares

procedures using the SHELXL program (version 2018/3)4 through the OLEX25

graphical interface. All non-hydrogen atoms, including those in disordered parts, were

refined anisotropically. All H-atoms were included at calculated positions and refined

as riders, with Uiso(H) = 1.2 Ueq(C) and Uiso(H) = 1.5 Ueq(C) for methyl groups. In

each unit cell, there are 3 methanol molecules that were found to be severely disordered

and hard to be modeled with disorders so they were removed by the SQUEEZE routine

in PLATON (version 220719).6 The total void volume was 171.1 Å3 indicated by

PLATON, equivalent to 5.56% of the unit cell’s total volume. Further crystal and data

collection details are listed in Table S1.

1•4Cl- was dissolved in MeOH and the solution was passed through a 0.45-μm filter

into a 10-mL tube, which was placed inside a 500-mL wild-mouth bottle containing

diethyl ether (50 mL). The bottle was capped, after slow evaporation of diethyl ether at

4℃ into the MeOH solution for 7 day, and colorless single crystals of 1•4Cl- were

obtained.

The crystal of 2•4PF6-: Data collections was performed on Bruker VENTURE system

with PHOTON 100 CMOS detector equipped and a Ga-target Liquid METALJET D2

PLUS X-ray Source (λ = 1.34139 Å). The data was collected at 180 K crystal

temperature (Oxford Cryosystems CRYOSTREAM 700), 50 kV and 30 mA with an

appropriate 0.5° ω and φ scan strategy. Data reduction and integration were performed

with SAINT (version 8.38A).1 Data was corrected for absorption effects using the

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empirical methods as implemented in SADABS (version 2016/2).2 The structure was

solved by SHELXT (version 2018/2)3 and refined by full-matrix least-squares

procedures using the SHELXL program (version 2018/3)4 through the OLEX25

graphical interface. All non-hydrogen atoms, including those in disordered parts, were

refined anisotropically. All H-atoms were included at calculated positions and refined

as riders, with Uiso(H) = 1.2 Ueq(C). In each unit cell, there are 20 acetonitrile

molecules that were found to be severely disordered and removed by the SQUEEZE

routine in PLATON (version 220719).6 The total void volume was 1631.8 Å3 indicated

by PLATON, equivalent to 35.86 % of the unit cell’s total volume. Further crystal and

data collection details are listed in Table S2.

2•4PF6- was dissolved in MeCN and the solution was passed through a 0.45-μm filter

into a 10-mL tube, which was placed inside a 500-mL wild-mouth bottle containing

diethyl ether (50 mL). The bottle was capped, after slow evaporation of diethyl ether at

4℃ into the MeCN solution for 7 day, and light-yellow single crystals of 2•4PF6- were

obtained.

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Table S1. Crystal data and structure refinement for 1•4Cl-

Chemical formula C61.50H74Cl4N8O7.50

Mr 1187.08

Crystal system, space group Triclinic, P¯1

Temperature (K) 114

a, b, c (Å) 11.8059 (14), 14.764 (2), 19.268 (2)

α, β, γ (°) 78.553 (5), 73.274 (4), 75.000 (5)

V (Å3) 3078.7 (7)

Z 2

F(000) 1254

Dx (Mg m-3) 1.281

Radiation type Mo Kα

μ (mm-1) 0.25

Crystal size (mm) 0.12 × 0.09 × 0.06

Diffractometer Bruker D8 Venture PHOTON 100 CMOS

Radiation source fine-focus sealed tube

Scan method ϕ and ω scans

Absorption correction Multi-scan SADABS2016/2 (Bruker, 2016/2) was

used for absorption correction. The Ratio of minimum to maximum transmission is 0.9069. The λ/2 correction factor is Not present.

Tmin, Tmax 0.572, 0.631

No. of measured, independent and observed [I > 2 (I)] reflections𝜎

49040, 10847, 7281

Rint 0.057

θ values (°) θmax = 25.1, θmin = 2.2

(sin θ/λ)max (Å-1) 0.596

Range of h, k, l h = -14→14, k = -17→17, l = -22→22

R[F2 > 2σ(F2)], wR(F2), S 0.073, 0.202, 1.05

S15

No. of reflections 10847

No. of parameters 757

No. of restraints 88

∆>max, ∆>min (e Å-3) 1.05, -0.81aR1 = ||Fo|-|Fc||/|Fo|. bwR2 = [[w(Fo2-Fc2)2]/[w(Fo2)2]].cQuality-of-fit = [[w(Fo2-Fc2)2]/(Nobs-Nparams)]½, based on all data.

S16

Table S2. Crystal data and structure refinement for 2•4PF6-

Chemical formula C90H82F24N18P4

Mr 1995.61

Crystal system, space group Tetragonal, P42212

Temperature (K) 180

a, c (Å) 19.429 (4), 12.057 (2)

V (Å3) 4551 (2)

Z 2

F(000) 2048

Dx (Mg m-3) 1.456

Radiation type Ga Kα, λ= 1.34138 Å

μ (mm-1) 1.10

Crystal size (mm) 0.17 × 0.12 × 0.09

Diffractometer Bruker D8 Venture PHOTON 100 CMOS

Radiation source Liquid METALJET D2 PLUS X-ray Source

Scan method ϕ and ω scans

Absorption correction Multi-scan SADABS2016/2 (Bruker,2016/2) was

used for absorption correction.

Tmin, Tmax 0.875, 0.956

No. of measured, independent and observed [I > 2σ(I)] reflections

30148, 4325, 3598

Rint 0.077

θ values (°) θmax = 54.9, θmin = 4.0

(sin θ/λ)max (Å-1) 0.610

Range of h, k, l h = -23→23, k = -23→20, l = -14→14

R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.142, 1.06

No. of reflections 4325

No. of parameters 240

∆>max, ∆>min (e Å-3) 0.24, -0.22

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Absolute structure Flack x determined using 1313 quotients [(I+)-(I-)]/[(I+)+(I-)]

(Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).

Absolute structure parameter 0.019 (12)aR1 = ||Fo|-|Fc||/|Fo|. bwR2 = [[w(Fo2-Fc2)2]/[w(Fo2)2]].cQuality-of-fit = [[w(Fo2-Fc2)2]/(Nobs-Nparams)]½, based on all data.

Figure S13. The torsion angles four benzene rings of TPE in 1•4Cl-.

S18

Figure S14. The torsion angles four benzene rings of TPE in 2•4PF6-.

Figure S15. The C–H…F interaction along the c axis between the PF6- ions and the

protons of aromatic rings.

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UV/vis, Fluorescence and PXRD experiments

Table S3. Absolute quantum yield (ΦF, %) of different solvents and solid of 1•4PF6-,

1•4Cl-, 2•4PF6- and 2•4Cl-. (λex = 350 nm for 1; 365nm for 2)

solvents 1•4PF6- 1•4Cl- 2•4PF6- 2•4Cl-

H2O 6.47 6.34 4.29 6.07

MeOH 8.27 17.41 12.07 14.84

CHCl3 41.52 - 11.55 -

MeCN 14.38 21.56 25.21 37.86

Acetone - 27.99 - 5.37

DCM 32.16 - 17.98 -

THF 35.94 27.22 10.28 5.90

Dioxane 26.21 29.04 28.83 13.86

EA 17.28 - 17.98 -

EtOH - 20.03 - 25.53

solid 17.93 16.47 4.42 3.81

Figure S16. The fluorescence emission spectra of 1•4PF6- (20 μM) in CHCl3 (1%

MeCN) and in the solid state. λex = 350 nm.

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Figure S17. UV/vis spectra of 1•4PF6- (20 μM) in different solvents (1% MeCN). A =

MeCN; B = H2O; C = CHCl3; D = Dioxane; E = THF; F = EA; G = MeOH; H = DCM.

Figure S18. (a) UV/vis spectra and (b) Fluorescence spectra of 1•4Cl- (20 μM) in

different solvents (1% H2O). A = H2O; B = MeCN; C = MeOH; D = THF; E = Dioxane;

F = Acetone; G = EtOH. (Inset) Fluorescence images under UV light (365 nm). λex =

350 nm.

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Figure S19. (a) UV/vis spectra and (b) Fluorescence spectra of 2•4PF6- (20 μM) in

different solvents (1% MeCN). A = MeCN; B = H2O; C = CHCl3; D = Dioxane; E =

THF; F = EA; G = MeOH; H = DCM. (Inset) Fluorescence images under UV light (365

nm). λex = 365 nm.

Figure S20. (a) UV/vis spectra and (b) Fluorescence spectra of 2•4Cl- (20 μM) in

different solvents (1% H2O). A = H2O; B = MeCN; C = MeOH; D = THF; E = Dioxane;

F = Acetone; G = EtOH. (Inset) Fluorescence images under UV light (365 nm). λex =

365 nm.

S22

Figure S21. Comparison of the PXRD profiles of 1•4PF6- before and after grinding.

Figure S22. Solid fluorescence spectra of 2•4PF6- before and after grinding. λex = 365 nm.

S23

High-pressure experimentsThe high-pressure experiments were performed in a set of diamond anvil cell (BGI-

type DAC) with 500 μm in diameter. T301 stainless steel sheets served as gaskets with

sample chambers of 200 μm in diameter and 250 μm in thickness. A small ruby chip

along with sample was loaded into the sample chamber for in situ pressure calibration

according to monitoring the fluorescence of the ruby R1 line. Meanwhile, in order to

provide a guarantee for obtaining the hydrostatic pressure according to the Pascal’s

principle, silicone oil was used in the experiments as a pressure-transmitting medium

(PTM). The measurements of the ruby chip were performed at a Horiba Jobin Yvon

T64000 Raman spectrometer with a 1800 gr mm−1 holographic grating. The high-

pressure fluorescence spectra under grinding and hydrostatic conditions were measured

using a fluorescence microscope (IX71, Olympus 20×, numerical aperture = 0.4)

equipped with a spectrometer (Horiba Jobin Yvon iHR320), and the light source of

which was a mercury lamp with an excitation wavelength of 365 nm.

Figure S23. (a) fluorescent images, (b) and (c) fluorescence spectra of the powder

samples of 1•4Cl- in the increasing and decreasing pressure processes. λex = 365 nm.

S24

Figure S24. (a) fluorescent images, (b) and (c) fluorescence spectra of the powder

samples of 2•4Cl- in the increasing and decreasing pressure processes. λex = 365 nm.

Figure S25. 3D Fluorescence spectra of 2•4PF6- (10 μM-60 μM) after exposure to a

UV-flashlight. λex = 365 nm.

S25

Figure S26. Relative photochemical reation ratio under the different condition of

2•4PF6- (10μM-60 μM). λex = 365 nm.

Figure S27. 1H NMR spectrum recorded (400 MHz, CD3CN, RT) for 2•4PF6- and

2•4PF6- after exposure to a UV-light (λem = 365 nm).

S26

Figure S28. Experimental and calculated electrospray ionization mass spectra of

2•4PF6- after exposure to a UV-light (λem = 365 nm).

Figure S29. (a) Fluorescence spectra and (b) the 1931 CIE chromaticity coordinate

changes of 1•4PF6- (20 μM) after exposure to a UV-flashlight. λex = 350 nm.

S27

Figure S30. 1H NMR spectrum recorded (400 MHz, CD3CN, RT) for 1•4PF6- and

1•4PF6- after exposure to a UV-light (λem = 365 nm).

Figure S31. Experimental and calculated electrospray ionization mass spectra of

1•4PF6- after exposure to a UV-light (λem = 365 nm).

S28

Reference:

1. SAINT; part of Bruker APEX3 software package (version 2017.3-0): Bruker AXS,

2017.

2. SADABS; part of Bruker APEX3 software package (version 2017.3-0): Bruker AXS,

2017.

3. G. M. Sheldrick, Acta Cryst. 2015, A71, 3-8.

4. G. M. Sheldrick, Acta Cryst. 2015, C71, 3-8.

5. O.V. Dolomanov, L.J. Bourhis, R.J, Gildea, J.A.K. Howard, H. Puschmann, J. Appl.

Cryst. 2009, 42, 339-341.

6. A. L. Spek, Acta Cryst. 2015, C71, 9−19.