with Aggregation-Induced Emission Characteristics

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1 Supporting Information Fluorogenic Zn(II) and Chromogenic Fe(II) Sensors ased on Terpyridine-Substituted Tetraphenylethenes with Aggregation-Induced Emission Characteristics Yuning Hong, Sijie Chen, Chris Wai Tung Leung, Jacky Wing Yip Lam, Jianzhao Liu, ai-wen Tseng, Ryan Tsz Kin Kwok, Yong Yu, Zhengke Wang, and en Zhong Tang*,,,# Department of Chemistry, ano Science and Technology Program, Institute of Molecular Functional Materials, ioengineering Program, and Department of Chemical and iomolecular Engineering, The Hong Kong University of Science & Technology (HKUST), Clear Water ay, Kowloon, Hong Kong, China, and # Department of Polymer Science and Engineering, Institute of iomedical Macromolecules, Key Laboratory of Macromolecular Synthesis and Functionalization of the Ministry of Education, Zhejiang University, Hangzhou 3127, China Contents Experimental Details Aggregation-Induced Emission Fluorogenic Zn(II) Sensing Chromogenic Fe(II) Sensing Particle Size Analysis (3) (9) (1) (14) (16) References (16) 1

2 Figure S1. Particle size distributions of (A) TPETPy, () TPE2TPy in THF/water mixture (1:99 v/v), where d e is effective diameter and d m is mean diameter. [TPE] = 2.5 μm; [metal ion] = 1 μm. (9) Figure S2. Change in FL intensity of (A) TPETPy and () TPE2TPy in aqueous buffer with different ph value. [TPE] = 1. μm; λ ex = 35 nm. (9) Figure S3. Change in FL intensity of (A) TPETPy and () TPE2TPy with different amounts of TFA concentration in THF. [TPE] = 1. μm; λ ex = 35 nm. (1) Figure S4. (A) Emission spectra of TPE2TPy in the presence of different concentrations of Zn 2+ in THF/water mixture (1:99 v/v). () Reciprocal of FL intensity at 545 nm vs. Zn 2+ concentration. [TPE] = 1. μm; λ ex = 35 nm. (1) Figure S5. (A) Emission spectra of TPE2TPy in the presence of different concentrations of Zn 2+ in THF. () FL intensity of TPE2TPy recorded at 55 nm vs. Zn 2+ concentration. [TPE] = 2.5 μm; λ ex = 35 nm. (11) Figure S6. Emission spectra of (A) TPETPy and () TPE2TPy with different metal ions in THF. [TPE] = 2.5 μm; [metal ion] = 1 μm; λ ex = 35 nm. (11) Figure S7. Determination of the stoichiometry in the binding process of TPE2TPy to Zn 2+. (12) Figure S8. Emission spectra of THF/water mixtures (1:99 v/v) of TPE2TPy/Zn 2+ complex containing various metal ions. [TPE] = 2.5 μm; [Zn 2+ ] = 1 μm; [metal ion] = 1 μm; λ ex = 35 nm. (12) Figure S9. UV spectra of TPE2TPy/Zn 2+ complex formed by mixing different concentration ratios of TPE2TPy to Zn 2+ in THF/water mixture (1:99 v/v). The total concentration of TPE2TPy and Zn 2+ is kept at 1 μm. (13) Figure S1. Zn 2+ -induced fluorescence change shown in different matrices. (13) Figure S11. UV spectra of THF/water mixtures (1:99 v/v) of TPE2TPy containing various cations. [TPE] = 2.5 μm; [metal ion] = 1 μm. (14) Figure S12. (A) UV spectra of TPE2TPy in the presence of ferrous ions in THF/water mixtures (1:99 v/v). () Relative absorbance response recorded at 575 nm. [TPE] = 2.5 μm. (15) 2

3 Figure S13. Determination of the stoichiometry in the binding process of TPE2TPy to Fe 2+. (15) Figure S14. Possible stoichiometry of Fe 2+ -TPE2TPy complex and structure of Fe 2+ -bound TPE2TPy. (16) Table S1. Particle Size Analysis of Dye Aggregates by Dynamic Light Scattering. (16) Experimental Details Materials and Instruments. Tetrahydrofuran (THF; Labscan) was purified by distillation from sodium benzophenone ketyl under nitrogen immediately prior to use. 2-Acetylpyridine, sodium hydroxide, ammonium acetate, 4-bromobenzophenone, titanium(iv) chloride, zinc dust, and other reagents were all purchased from Aldrich and used as received. Inorganic salts including zinc perchlorate, magnesium chloride, rhodium(iii) chloride, lead(ii) chloride, ruthenium(iii) chloride hydrate, cadmium(ii) chloride, iron(ii) chloride, iron(iii) chloride, cobalt(ii) chloride, nickel(ii) chloride, and copper(ii) chloride are purchased from Aldrich or International Laboratory. The syntheses of 4 -(4-bromophenyl)-2,2 :6,2 -terpyridine and TPE2TPy were described in our previous publication. 1 1 H and 13 C MR spectra were measured on a ruker AV 4 spectrometer using tetramethylsilane (TMS; δ = ) as internal standard. High resolution mass spectra (HRMS) were recorded on a Finnigan TSQ 7 triple quadrupole spectrometer operating in a MALDI-TOF mode. UV spectra were measured on a Milton Roy Spectronic 3 Array spectrophotometer and the FL spectra were recorded on a Perkin-Elmer LS 55 spectrofluorometer with a Xenon discharge lamp excitation. Samples for absorption and emission measurements were carried out in 1 cm 1 cm quartz cuvettes. FL quantum yields (Φ F,s ) in solution were estimated by reference to quinine sulfate in.1 M H 2 SO 4 (Φ F,s = 54%). Solid state quantum yields were determined by a calibrated integrating sphere. Particle size analyses were determined at room temperature by a ZetaPlus Potential Analyzer (rookhaven Instruments Corporation, USA). Millipore water was used to prepare all aqueous solutions. All experiments were performed at room temperature (~25 o C) unless otherwise specified. 3

4 O r aoh, PEG r H 4 OAc r H O aq. EtOH O 1 O EtOH 2 Synthesis of 4 -(4-romophenyl)-2,2 :6,2 -terpyridine (2). 2-acetylpyridine (5 g, 4.12 mmol) was added to a suspension of crushed aoh (1.2 g, 8.25 mmol) in 7 ml of poly(ethylene glycol) (PEG, average molecular weight = 3). After the solution was stirred at o C for 1 min, 4- bromobenzaldehyde (3.76 g, 2.6 mmol) was then added by syringe and the suspension was kept at o C for 2 h. Every 15 min, the suspension was manually stirred with a spatula as the viscosity became too great for adequate mixing using a magnetic stirrer. After 2 h, excess ammonium acetate (2 g) was added and the suspension was heated at 1 o C for 2 h. The color of the mixture changed from red to brown accompanied with the formation of fine brown precipitate. Water (15 ml) was added to the solution and the precipitate of 2 was isolated by filtration and washed with water (1 ml) and cold ethanol (2 ml). The crude product was purified on a basic aluminium oxide column using hexane/chloroform (1:1 v/v) as eluent. 2 was obtained as white powder in 75% yield (6.5 g). 1 H MR (4 MHz, CDCl 3 ), δ (ppm): (m, 6H), (m, 2H), (d, 2H), (d, 2H), (m, 2H). 13 C MR (1 MHz, CDCl 3 ), δ (ppm): 156., 155.9, 149.1, 148.9, 137.3, 136.9, 132., 128.8, 123.9, 123.4, 121.3, MS (TOF), m/e [(M+H) +, calcd ]. 1. n-uli, THF, -78 o C 1. n-uli O r 3 2. (OMe) 3 3. HCl, H 2 O r 4 (OH) 2 2 Pd(PPh 3 ) 4 /a 2 CO 3 THF/H 2 O TPETPy 4

5 Synthesis of 1-(4-bromophenyl)-1,2,2-triphenylethene (3). To a solution of diphenylmethane (2.2 g, 12 mmol) in dry THF (2 ml) was added 4 ml of a 2.5 M solution of n-butyllithium in hexane (1 mmol) in an acetone dry ice bath at 78 C under nitrogen atmosphere. The resulting orange-red solution was stirred for 3 min at that temperature. To this solution was added 4-bromobenzophenone (9 mmol) and the reaction mixture was allowed to warm to room temperature with stirring for 6 h. The reaction was quenched with the addition of an aqueous solution of ammonium chloride, the organic layer was extracted with DCM, and the combined organic layers were washed with a saturated brine solution and dried over anhydrous MgSO 4. The solvent was evaporated, and the resulting crude alcohol was subjected to acid-catalyzed dehydration as follows. The crude alcohol was dissolved in about 8 ml of toluene in a 1 ml Schlenk flask fitted with a Dean-Stark trap. A catalytic amount of p-toluenesulphonic acid (342 mg, 1.8 mmol) was added, and the mixture was refluxed for 3 4 h and cooled to room temperature. The toluene layer was washed with 1% aqueous ahco 3 solution, dried over anhydrous MgSO 4 and evaporated to afford the crude tetraphenylethylene derivative (3). The crude product was purified on a silica-gel column using hexane as eluent. 3 was isolated as intermediate in the reaction as a white solid in 93.6% yield. 1 H MR (4 MHz, CDCl 3 ), δ (TMS, ppm): 7.21 (d, 2H), (m, 9H), (m, 6H), 6.88 (d, 2H). 13C MR (CDCl3, 1 MHz) δ (ppm): 126.4, , , 127., 127.3, , 127.9, , 128.9, , , 132., 139., 14.7, 14.8, 141.3, 143., , Synthesis of 4-(1,2,2-Triphenylvinyl)phenylboronic acid (4). Into a 25 ml two-necked roundbottom flask under nitrogen was slowly added n-butyllithium (1.6 M in hexane, 7.5 ml, 12 mmol) and a THF solution (8 ml) of 3 (4.11 g, 1 mmol) at 78 o C. After stirring for 3 h, 2.4 ml of trimethylborate (2 mmol) was added into the reaction mixture. The mixture was warmed to room temperature and the reaction was terminated by adding hydrochloric acid (2 M, 1 ml) after 12 h. The mixture was then poured into water and extracted with dichloromethane. The organic layer was washed with water and dried over magnesium sulfate. After filtration and solvent evaporation, the residue was purified by silica-gel column chromatography using n-hexane/ethyl acetate as eluent. White solid of 4 was obtained 5

6 in 7% yield (2.6 g). 1 H MR (3 MHz, CDCl 3 ), δ (TMS, ppm): 7.88 (d, 2H, J = 8.1 Hz), (m, 17H), 4.49 (s, 1H). 13 C MR (75 MHz, CDCl 3 ), δ (TMS, ppm): 148.9, 144.2, 144.1, 144.9, 142.4, 141.4, 135.6, 133.5, 132., 131.6, 128.4, 128.3, 127.4, HRMS (TOF): m/e (M +, calcd ). Synthesis of 1-[4'-(4'-2,2':6',2"-Terpyridyl)-biphenyl-4-yl]-1,2,2-triphenylethene (TPETPy). 4 (.3 g,.71 mmol), 2 (.5 g, 1.43 mmol), and tetrakis (triphenylphosphine)palladium() (41 mg,.36 mmol) were dissolved in 3 ml of degassed THF. 3 ml of saturated aqueous a 2 CO 3 solution was added to the mixture under stirring. After reflux for 48 h, the reaction mixture was cooled to room temperature and filtered. The solvent was evaporated under vacuum and the organic solution was washed with water three times. The crude product was purified on a basic aluminium oxide column using hexane/chloroform (1:1 v/v) as eluent. TPETPy was obtained as yellow powder in 48% yield (.2 g). 1 H MR (4 MHz, CDCl 3 ), δ (ppm): 8.78 (s, 2H), (m, 8H), (d, 2H), (m, 4H), (t, 5H), (d, 2H), (m, 4H), (m, 4H), (m, 2H). 13 C MR (1 MHz, CDCl 3 ), δ (ppm): 156., 155.7, 151.4, 149.4, 148.9, 148.7, 143.5, 142.9, 141.1, 141., 14.3, 137.8, 137.1, 136.8, 136.6, 135.7, 131.9, 131.7, 131.3, 131.2, 128.6, 128.1, 127.7, 127.5, 127.4, 127.1, 126.4, 126.3, 126., HRMS (TOF), m/e (M +, calcd ). O r (OH) 2 TiCl 4 /Zn 1. n-uli, THF, -78 o C r THF 2. (OMe) 3 3. HCl, H 2 O r 5 (HO) Pd(PPh 3 ) 4 /a 2 CO 3 THF/H 2 O TPE2TPy 6

7 Synthesis of 1,2-is(4-bromophenyl)-1,2-diphenylethene (5). In a suspension of 4- bromobenzophenone (5 g, 19.2 mmol) in 5 ml of THF were added TiCl 4 (2.14 ml, 19.2 mmol) and Zn dust (2.48 g, 38.4 mmol). After reflux for 2 h, the reaction mixture was cooled to room temperature and filtered. The solvent was evaporated under vacuum and the crude product was purified by a silica gel column using hexane as eluent. Compound 5 was obtained as white solid in 95% yield (4.3 g). 1 H MR (CDCl 3, 3 MHz), δ (ppm): (m, 4H), (m, 6H), 6.98 (m, 4H), (m, 4H). 13 C MR (CDCl 3, 75 MHz), δ (TMS, ppm): 133., 131.3, 131.2, 131., 128.1, 127.9, 127.8, 127., MS (TOF): m/e (M +, calcd. 49.). Synthesis of 4,4'-(1,2-Diphenylethene-1,2-diyl) bis(1,4-phenylene)diboronic acid (6). Into a 1 ml flask was dissolved 5 (.4 g,.82 mmol) in 2 ml of THF. The flask was cooled in an acetone dry ice bath at 78 C and 1. ml (2.6 mmol) of n-butyllithium (2.5 M in hexane) was added carefully. After stirring for 1h,.46 ml (4. mmol) of trimethyl borate was added and the mixture was allowed to react for 45 min. The mixture was warmed to room temperature and stirred overnight. Dilute HCl solution was then added to quench the reaction. After filtration and solvent evaporation, the product was purified by silica gel column using ethyl acetate as eluent. The product was obtained as yellow solid in 54% yield. 1 H MR (CD 3 OD, 3MHz) δ (ppm): (m, 1H), (m, 4H), (m, 4H). 13 C MR (CD 3 OD, 75MHz), δ (TMS, ppm): 157.2, 146.2, 141.4, 137., 133.9, 132.7, 128.9, 127.4, MS (TOF): m/e [(M) +, calcd: 422.1]. Synthesis of 1,2-is[4 -(4-2,2 :6,2 -terpyridyl)-biphenyl-4-yl]-1,2-diphenylethene (TPE2TPy). 6 (.3 g,.71 mmol), 2 (.5 g, 1.43 mmol), and tetrakis (triphenylphosphine)palladium() (41 mg,.36 mmol) were dissolved in 3 ml of degassed THF. 3 ml of saturated aqueous a 2 CO 3 solution was added to the mixture under stirring. After reflux for 48 h, the reaction mixture was cooled to room temperature and filtered. The solvent was evaporated under vacuum and the organic solution was washed with water three times. The crude product was purified on a basic aluminium oxide column using hexane/chloroform (1:1 v/v) as eluent. TPE2TPy was obtained as yellow powder in 52% yield 7

8 (.37 g). 1 H MR (4 MHz, CDCl 3 ), δ (ppm): (m, 8H), (m, 4H), (t, 4H), (d, 2H), (m, 4H), (m, 4H), (m, 6H), (m, 4H), (m, 4H), (m, 4H). 13 C MR (1 MHz, CDCl 3 ), δ (ppm): 156.1, 149.1, 143.4, 136.9, 132., 128.6, 127.5, 126.2, 123.9, 121.4, 118.6, HRMS (TOF): m/e (M +, calcd ). Preparation of anoaggregates. Stock solutions of the TPE derivatives in THF with a concentration of 25 μm were prepared. Aliquots (.1 ml) of the stock solutions were transferred to 1 ml volumetric flasks. After adding appropriate amounts of THF, water was added dropwise under vigorous stirring to furnish 1 μm solutions with defined fractions of water (fw = 99 vol %). Spectral measurements of the resultant solutions or aggregate suspensions were performed immediately. Sample Preparation for FL Measurement. Stock solutions of the TPE derivatives in THF was diluted to 2.5 μm using water, followed by the addition of an aliquot of different metal ions. The final concentration of the metal ions was 1 μm unless specified. The solutions were mixed by Vortex and stood for 1 min prior to spectral measurement. Solid-state Cation Sensing. The TPE derivatives were mixed with poly(methyl methacrylate) (PMMA) in weight ratio of 1:2 and then dissolved in dichloromethane (DCM) before pouring into Petri dishes. The Petri dishes were covered with a top and the solvent was slowly evaporated to dryness. 2 The transparent and homogeneous thin film was covered with a shadow mask with the fingerprint (herein, letter A ) exposed to acetonitrile solution of zinc perchlorate (1-4 M). The solvent was allowed to evaporate in air for 1 h before the removal of the mask. Cotton swab tip was dipped into aqueous solution of zinc acetate (1-4 M) and used for writing patterns (e.g., letters HK ) on a filter paper strip. The strip was immersed into DCM solution of TPE2TPy. After solvent evaporation, the letters can be easily seen when illuminated under UV light. Either TLC plates or paper strips were first immersed into the solution of DCM solution of TPE2TPy. After solvent evaporation, the plates/strips are ready for cation sensing. 8

9 Aggregation-Induced Emission. 1 8 A Intensity 6 4 TPETPy d e = 93.3 nm d m = nm TPE2TPy d e = 1.3 nm d m = nm Particle size (nm) Particle size (nm) Figure S1. Particle size distributions of (A) TPETPy, () TPE2TPy in THF/water mixture (1:99 v/v), where d e is effective diameter and d m is mean diameter. [TPE] = 2.5 μm; [metal ion] = 1 μm PL 485 nm PL 496 nm A ph value ph value Figure S2. Change in FL intensity of (A) TPETPy and () TPE2TPy in aqueous buffer with different ph value. [TPE] = 1. μm; λ ex = 35 nm. 9

10 PL 485 nm A PL 496 nm [TFA] (mm) [TFA] (mm) Figure S3. Change in FL intensity of (A) TPETPy and () TPE2TPy with different amounts of TFA concentration in THF. [TPE] = 1. μm; λ ex = 35 nm. Fluorogenic Zn(II) Sensing. 4 A [Zn 2+ ] (μm) PL intensity (au) /I [Zn 2+ ] (μm) Figure S4. (A) Emission spectra of TPE2TPy in the presence of different concentrations of Zn 2+ in THF/water mixture (1:99 v/v). () Reciprocal of FL intensity at 545 nm vs. Zn 2+ concentration. [TPE] = 1. μm; λ ex = 35 nm. 1

11 A PL intensity (au) PL 55 nm [Zn 2+ ] (μm) Figure S5. (A) Emission spectra of TPE2TPy in the presence of different concentrations of Zn 2+ in THF. () FL intensity of TPE2TPy recorded at 55 nm vs. Zn 2+ concentration. [TPE] = 2.5 μm; λ ex = 35 nm PL intensity (au) 75 5 A blank a + Ca 2+ Zn 2+ blank a + Ca 2+ Zn PL intensity (au) Figure S6. Emission spectra of (A) TPETPy and () TPE2TPy with different metal ions in THF. [TPE] = 2.5 μm; [metal ion] = 1 μm; λ ex = 35 nm. 11

12 PL Intensity (au) A PL intensity (au) Peak position (nm) [Zn 2+ ]/([Zn 2+ ]+[TPE2TPy]) Figure S7. Determination of the stoichiometry in the binding process of TPE2TPy to Zn 2+. (A) Emission spectra of TPE2TPy/Zn 2+ complex formed by using different concentration ratios of TPE2TPy to Zn 2+ in THF. () Dependence of the emission peak position and PL intensity vs. the concentration ratio of Zn 2+ to the total concentrations of TPE2TPy and Zn 2+ (1 μm). λ ex = 35 nm. PL intensity (au) Zn 2+ Zn 2+ /Cd 2+ Zn 2+ /Rh 3+ Zn 2+ /Pb 2+ Zn 2+ /Mg 2+ Zn 2+ /i 2+ Zn 2+ /Fe 2+ Zn 2+ /Fe 3+ Zn 2+ /Co 2+ Zn 2+ /Cu Figure S8. Emission spectra of THF/water mixtures (1:99 v/v) of TPE2TPy/Zn 2+ complex containing various metal ions. [TPE] = 2.5 μm; [Zn 2+ ] = 1 μm; [metal ion] = 1 μm; λ ex = 35 nm. 12

13 [Zn 2+ ]/[Zn 2+ ]+[TPE] Absorbance (au) Figure S9. UV spectra of TPE2TPy/Zn 2+ complex formed by mixing different concentration ratios of TPE2TPy to Zn 2+ in THF/water mixture (1:99 v/v). The total concentration of TPE2TPy and Zn 2+ is kept at 1 μm. Figure S1. Zn 2+ -induced fluorescence change shown in different matrices. Fluorescence images of (A) TPETPy-doped PMMA film, () filter paper stained by TPE2TPy, and (C) TLC plate soaped in TPE2TPy taken under illumination of UV light. (A) The TPETPy-doped PMMA film was covered with a shadow mask with the letter A exposed to the acetonitrile solution of Zn(OCl 4 ) 2. After solvent evaporation, the mask was removed before UV illumination. () The letters HK were written on filter paper by aqueous solution of Zn(OAc) 2. The filter paper was soaped into DCM solution of TPE2TPy followed by solvent evaporation. (C) The TLC plate was first immersed into the solution DCM solution 13

14 of TPE2TPy. After solvent evaporation, the TLC plate was then partially dipped into aqueous solution of Zn(OAc) 2. Chromogenic Fe(II) Sensing. Absorbance (au) blank Fe 2+ Fe 3+ Cd 2+ Co 2+ Cu 2+ Mg 2+ i 2+ Pb 2+ Ru 3+ Rh 3+ Zn Figure S11. UV spectra of THF/water mixtures (1:99 v/v) of TPE2TPy containing various cations. [TPE] = 2.5 μm; [metal ion] = 1 μm. 14

15 2 [Fe 2+ ] (μm) A Absorbance (au) A/A [Fe 2+ ] (μm) Figure S12. (A) UV spectra of TPE2TPy in the presence of ferrous ions in THF/water mixtures (1:99 v/v). () Relative absorbance response recorded at 575 nm. [TPE] = 2.5 μm. Absorbance (au) A [Fe 2+ ]/([Fe 2+ ]+[TPE2TPy]) [Fe 2+ ]:[TPE2TPy] 2:3 576 nm [Fe 2+ ]/([Fe 2+ ]+[TTPE-2]) Figure S13. Determination of the stoichiometry in the binding process of TPE2TPy to Fe 2+. (A) UV spectra of TPE2TPy/Fe 2+ complex formed by mixing different concentration ratios of TPE2TPy to Fe 2+ in THF/water mixture (1:99 v/v). () Dependence of the absorbance at 576 nm vs. the concentration ratio of Fe 2+ to the total concentration of TPE2TPy and Fe 2+ (1 μm). 15

16 Figure S14. Possible stoichiometry of Fe 2+ -TPE2TPy complex and structure of Fe 2+ -bound TPE2TPy. Particle Size Analysis. Table S1. Particle Size Analysis of Dye Aggregates by Dynamic Light Scattering d e (nm) a d m (nm) b PD c TPETPy TPETPy/Zn TPETPy/Fe TPE2TPy TPE2TPy/Zn TPE2TPy/Fe a Effective diameter. b Mean diameter. c Polydispersity. References 1 Tong, H.; Hong, Y.; Dong, Y.; Haussler, M.; Li, Z.; Lam, J. W. Y.; Dong, Y.; Sung, H. H. Y.; Williams, I. D.; Tang,. Z. J. Phys. Chem. 27, 111, Goze, C.; Ulrich, G.; Charbonnière, L.; Cesario, M.; Prangé, T.; Ziessel R., Chem. Eur. J. 23, 9,