Gelation of Luminescent Supramolecular Cages and Transformation. to Crystals with Trace-Doped-Enhancement Luminescence

Transcription

1 Supporting Information Gelation of Luminescent Supramolecular Cages and Transformation to Crystals with Trace-Doped-Enhancement Luminescence Juan Feng, Lihua Zeng, Kunyu Chen, Haobin Fang, Jianyong Zhang,* Zhenguo Chi and Cheng-Yong Su Sun Yat-Sen University, Lehn Institute of Functional Materials, MOE Laboratory of Bioinorganic and Synthetic Chemistry, MOE Key Laboratory of Polymeric Composite and Functional Materials, Guangzhou , China.

2 Experimental section Materials and methods. All reagents were analytical grade and used as received without further purification unless otherwise stated. 1,1,2,2-tetrakis(4-diphenylphosphino-(1,1'-biphenyl)ethane (L) was synthesized according to the reported method. 1 NMR spectra were recorded on a Bruker Avance III 400/500 MHz spectrometer. HR-ESI-TOF mass spectra were recorded on a Bluker ESI-Q-TOF Maxis 4G high-resolution mass-spectrometer. Scanning electron microscopy (SEM) images were collected on a Hitachi SU8010 Ultra-high Resolution FE-SEM. Before measurement, the aerogel sample was dispersed in CHCl 3 -CH 3 CN (v:v 5:3) with the aid of sonication, put on silicon plate, and sputter coated with gold. Transmission electron microscopy (TEM) investigations were carried out on a FEI Tecnai G2 Spirit 120 kv transmission electron microscope. The gel sample was dispersed in CHCl 3 -CH 3 CN (v:v 5:3) with the aid of sonication and mounted on a carbon coated copper grid. The photoluminescence spectra and time-resolved emission spectra were measured on a FLS980 Combined Lifetime and Steady State Fluorometer (Edinburgh Instruments Ltd.) and the luminescence quantum yields were determined on a Hamamatsu C G absolute PL quantum yield measurement system. Preparation of Ag 4 L 2 -dppb gel. A solution of L (27.4 mg, 0.02 mmol) in 1.0 ml CHCl 3 and a solution of AgBF 4 (7.8 mg, 0.04 mmol) in 0.6 ml CH 3 CN were mixed to form a yellowish green solution with the aid of sonication. To this solution dppb (17.1 mg, 0.04 mmol) was added rapidly with the aid of sonication. A transparent yellowish green gel was obtained within 30 s upon standing. AgL-dppb-I. An aqueous solution of tetrabutylammonium iodide (0.8 ml, 0.05 mol L -1 ) was layered on top of the above Ag 4 L 2 -dppb gel. The gel degraded gradually and crystals appeared after 1 h. The gel degraded completely overnight to yield pale green crystals (20 mg, 80%). Found (calcd.) for C 56 H 56 P 4 Ag 2 I 2 : C (50.86), H 4.68 (4.27) %. AgL-dppb-Br. An aqueous solution of tetrabutylammonium bromide (0.4 ml, 0.1 mol L -1 )

3 was layered on top of the above Ag 4 L 2 -dppb gel. The gel degraded gradually and crystals appeared after 1 h. The gel degraded completely overnight to yield pale green crystals (17 mg, 70%). Found (calcd.) for C 56 H 56 P 4 Ag 2 Br 2 : C 54.50(54.75), H 4.76(4.59)%. Rheological measurements. Rheological measurements were studied by using a HAAKE MARS(III) equipped with a 20-mm diameter steel parallel plate. The gap distance was fixed at 2.0 mm and measurements were conducted at 25 o C. Strain sweeps at a constant frequency (1.0 Hz) were performed in the 0.01~100 % range to determine the linear viscoelastic region of the gel sample. Frequency sweeps were obtained from 0.01 to 10 Hz at a constant strain within the linear regime determined by the strain sweep (0.1%). The dynamic time sweep was performed in 1.0 h at 1.0 Hz frequency and a constant strain within the linear regime determined by the strain sweep (0.1%). Thixotropy loop tests in response to applied shear force were investigated with the following procedure: 0.1% (3 min) 100% (1 min) 0.1% (3 min) 100% (1 min) 0.1% (3 min) 100% (1 min) 0.1% (3 min). The continuous and careful addition of solvent may prevent the evaporation of solvent and result in little fluctuation of the data. The frequency of the measurement was 1.0 Hz. Fluorescence experiments. In a 100 ml volumetric flask, mg of Ag 4 L 2 -dppb wet gel was added to 100 ml of H 2 O and dispersed by ultrasonic for 10 min to obtain a dispersion (c(l) = mol L -1 ). The fluorescence response in the range nm was monitored upon excitation at 440 nm (decided by UV-spectra, Figure S10) after incremental addition of PA solutions (0.2 mmol L -1 ). To maintain homogeneity, the fluorescence measurement was performed with continuous stirring for 1 min after PA was added. For calculating detection limit, TNP (0 200 μl, 0.02 μmol L -1 stock solution) was added to Ag 4 L 2 -dppb gel (171.1 mg, in 100 ml water) and fluorescent intensity was recorded. By plotting fluorescence intensity with increasing concentration of TNP, slope (m) of graph was found to be (R 2 = 0.994). Standard deviation (σ) was calculated from six

4 blank measurements of Ag 4 L 2 -dppb gel. Detection limit is calculated according to the formula: Detection limit = 3σ/m. X-ray crystallography. X-ray crystallographic data of AgL-dppb-I were collected at 291(2) K on an Agilent Technologies SuperNova X-ray diffractometer system equipped with CCD detector using Cu X-ray tube. The structure was solved by the direct method following difference Fourier syntheses, and refined by the full-matrix least-squares method against F 0 2 using SHELXL-2014/7 software. 2 All non-hydrogen atoms were refined with anisotropic thermal parameters while hydrogen atoms were introduced in the final refinement model in calculated positions with isotropic thermal parameters. Crystallographic data for AgL-dppb-I (yellow rod): C 56 H 56 Ag 2 P 4 I 2 M w = , monoclinic, P2(1)/n, a = (1), b = (2), c = (2) Å, α = γ = 90, β = (1), V = (5) Å 3, Z = 2, μ = mm -1, λ = Å, F(000) = 1304, reflections were collected (5202 were unique) for 4.03 <θ< 74.09, R(int) = , R = , wr 2 = [I > 2σ(I)], R = , wr 2 = (all data) for 289 parameters with no restraint, GOF = CCDC Unit cell for AgL-dppb-Br (yellowish green block): monoclinic, P2(1)/n, a = (6), b = (5), c = (4) Å, α = γ = 90, β = 99.34(4), V = 2534(2) Å 3. References (1) Feng, J.; Yao, L.; Zhang, J.; Mu, Y.; Chi Z.; Su, C.-Y. A Luminescent Silver-Phosphine Tetragonal Cage Based On Tetraphenylethylene. Dalton Trans. 2016, 45, (2) G. M. Sheldrick, Crystal structure refinement with SHELXL. Acta Cryst. 2015, C71, 3 8.

5 Tables, schemes and figures Ph 2 P PPh 2 Ph 2 P PPh 2 Ph 2 P PPh 2 N N H 2 N NH 2 H 2 N NH 2 Scheme S1. Bridging ligands (BL) tested. Table S1. Gelation tests of AgBF 4, L and dppb (Ag + :L:dppb = 2:1:2, c(l) = mol L -1 ) in various solvents. Entry Solvent DMF-CH 3OH (5:3) toluene-ch 3OH (5:3) 1,4-dioxane-CH 3CN (5:3) Result Yellowish green gel after Pale yellowish green Pale yellowish green 40 min suspension suspension Photo Table S2. Gelation tests of AgBF 4, L and dppb (Ag + :L = 2:1) at various molar ratios. Ag:L:dppb Result 4:2:2 Yellowish green solution 4:2:3 Transparent yellowish green gel within 5 s. 4:2:4 Transparent yellowish green gel within 5 s, turned opaque overnight 4:2:5 Opaque, pale yellowish green gel within 5 s Reaction conditions: L (13.7 mg, 0.01 mmol) and AgBF 4 (3.9 mg, 0.02 mmol) were mixed in CHCl 3 -CH 3 CN (0.8 ml, v:v 5:3) in the aid of sonication, and then dppb ( mmol) was added.

6 Table S3. Gelation tests of L and AgBF 4 at various molar ratios in various solvents (c(l) = mol L -1 ). L:AgBF 4 Solvent Result 1:0.33 CHCl 3 -CH 3 CN (5:3) Bright yellow solution 1:0.5 CHCl 3 -CH 3 CN (5:3) Yellowish green viscous solution 1:1 CHCl 3 -CH 3 CN (5:3) Yellowish green viscous solution 1:1.33 CHCl 3 -CH 3 CN (5:3) Pale yellowish green suspension 1:2 CHCl 3 -CH 3 CN (5:3) Yellowish green solution 1:1 CHCl 3 -CH 3 OH (5:3) Yellowish green suspension 1:1 1,4-dioxane-CH 3 CN (5:3) Pale green precipitate 1:1 1,4- dioxane -CH 3 OH (5:3) Pale yellow precipitate 1:1 DMF-CH 3 CN (7:3) Yellowish green solution 1:1 DMF-CH 3 OH (7:3) Yellowish green solution 1:1 toluene-ch 3 CN (7:3) Yellowish green viscous solution Figure S1. 31 P{ 1 H} NMR spectrum of L used in the gelation study (162 MHz, CDCl 3 ).

7 Intensity a b c d Figure S2. Photographs of a) Ag 4 L 2 -dppm gel, b) Ag 4 L 2 -dppb gel, c) Ag 4 L 2 -dpph gel and d) Ag 4 L 2 -PPh 3 suspension (Ag + :L:PPh 3 = 2:1:4) # # / o Figure S3. PXRD pattern of Ag 4 L 2 -dppb xerogel (Signals labeled with # symbols correspond to silicon plate).

8 Counts/s Counts/s Counts/s C 1s F 1s Ag 3d P 2p Binding energy / ev Ag 3d ev 3d 3/ ev 3d 5/ P 2p ev 2p 1/ ev 2p 3/ Binding energy / ev Binding energy / ev Figure S4. XPS survey, Ag 3d and P 2p core level spectra of Ag 4 L 2 -dppb xerogel (The atomic ratio of P/Ag is 4.0).

9 Counts/s Counts/s Counts/s C 1s F 1s Ag 3d P 2p Binding energy / ev Ag 3d ev 3d 3/ ev 3d 5/ P2p ev 2p 3/ ev 2p 1/ Binding energy / ev Binding energy / ev Figure S5. XPS survey, Ag 3d and P 2p core level spectra of Ag 4 L 2 cage (The atomic ratio of P/Ag is 2.2).

10 Ag 4 L 2 -dppb Ag 4 L Wavenumber/cm -1 Figure S6. FT-IR spectra of Ag 4 L 2 -dppb xerogel and Ag 4 L 2 (2917, 2859 (CH 2 ), 1074 cm -1 (BF - 4 ). Figure S7. Soild-state 31 P CP/MAS NMR spectrum of Ag 4 L 2 -dppb xerogel. Singals with # symbols are spinning sidebands.

11 Figure S8. 31 P{ 1 H} NMR titration of Ag 4 L 2 with PPh 3 (162 MHz, DMSO, c(l)= 0.04 mol L -1 in DMSO, reference: 85% conc. H 3 PO 4 ). Blue dotted lines highlight the change of Ag 4 L 2 signals and red ones highlight the changes of PPh 3 signals.

12 [Ag 2 L] 2+ [Ag 4 L 2 ] 4+ [Ag 4 L 2 +Cl] 3+ [2Ag 4 L 2 +10PPh 3 +Cl+BF 4 +4H 2 O] 6+ [Ag 4 L 2 +PPh 3 +Cl] 3+ [Ag 4 L 2 +5PPh 3 +Cl+2MeOH] 3+ [Ag 2 L+PPh 3 ] 2+ [Ag 4 L 2 +2PPh 3 +Cl] 3+ [Ag 4 L 2 +PPh 3 +2Cl] 2+ [Ag 4 L 2 +PPh 3 ] 4 [Ag 4 L 2 +2Cl] 2+ Figure S9. ESI-TOF-MS spectrum of Ag 4 L 2 -PPh 3 (1:8) in DMSO (diluted by MeOH). Partial mass spectroscopy data are shown as follow (Fig. S7-1-S7-10): m/z observed (simulated) for [C 214H 159P 9Ag 4Cl 2] 2+ ([Ag 4L 2 + PPh 3 + 2Cl] 2+ ), ( ); [C 196H 144P 8Ag 4Cl 2] 2+ ([Ag 4L 2 + 2Cl] 2+ ), ( ); [C 288H 227P 13Ag 4O 2Cl] 3+ [Ag 4L 2 + 5PPh 3 + Cl + 2CH 3OH] 3+, ( ); [C 572H 446P 26Ag 8O 4ClBF 4] 6+ [2Ag 4L PPh 3 + Cl + BF 4 + 4H 2O] ( ); [C 250H 189P 11Ag 4Cl] 3+ ([Ag 4L 2 + 3PPh 3 + Cl] 3+ ), ( ); [C 232H 174P 10Ag 4Cl] 3+ ([Ag 4L 2 + 2PPh 3 + Cl] 3+ ), ( ); [C 214H 159P 9Ag 4Cl] 3+ ([Ag 4L 2 + PPh 3 + Cl] 3+ ), ( ); [C 196H 144P 8Ag 4Cl] 3+ ([Ag 4L 2 + Cl] 3+ ), ( ) ; [C 232H 174P 10Ag 4] 4+ ([Ag 4L 2 + 2PPh 3] 4+ ), ( ); [C 116H 87P 5Ag 2] 2+ ([Ag 2L + PPh 3] 2+ ), ( ); [C 214H 159P 9Ag 4] 4+ ([Ag 4L 2 + PPh 3] 4+ ), ( ); [C 196H 144P 8Ag 4] 4+ ([Ag 4L 2] 4+ ), ( ); [C 98H 72P 4Ag 2] 2+ ([Ag 2L] 2+ ), ( ). Cl - may origin from CHCl 3 solvent. Figure S9-1. Observed and simulated isotopic distributions. HRMS: m/z found (calcd) for [C 214 H 159 P 9 Ag 4 Cl 2 ] 2+ ([Ag 4 L 2 + PPh 3 + 2Cl] 2+ ), ( ).

13 Figure S9-2. Observed and simulated isotopic distributions. HRMS: m/z found (calcd) for [C 196 H 144 P 8 Ag 4 Cl 2 ] 2+ ([Ag 4 L 2 + 2Cl] 2+ ), ( ). Figure S9-3. Observed and simulated isotopic distributions (overlaid). HRMS: m/z found (calcd) for [C 288 H 227 P 13 Ag 4 O 2 Cl] 3+ [Ag 4 L 2 + 5PPh 3 + Cl + 2CH 3 OH] 3+, ( ). [C 572 H 446 P 26 Ag 8 O 4 ClBF 4 ] 6+ [2Ag 4 L PPh 3 + Cl + BF 4 + 4H 2 O] ( ).

14 Figure S9-4. Observed and simulated isotopic distributions. HRMS: m/z found (calcd) for [C 250 H 189 P 11 Ag 4 Cl] 3+ ([Ag 4 L 2 + 3PPh 3 + Cl] 3+ ), ( ). Figure S9-5. Observed and simulated isotopic distributions. HRMS: m/z found (calcd) for [C 232 H 174 P 10 Ag 4 Cl] 3+ ([Ag 4 L 2 + 2PPh 3 + Cl] 3+ ), ( ). Figure S9-6. Observed and simulated isotopic distributions. HRMS: m/z found (calcd) for [C 214 H 159 P 9 Ag 4 Cl] 3+ ([Ag 4 L 2 + PPh 3 + Cl] 3+ ), ( ).

15 Figure S9-7. Observed and simulated isotopic distributions. HRMS: m/z found (calcd) for [C 196 H 144 P 8 Ag 4 Cl] 3+ ([Ag 4 L 2 + Cl] 3+ ), ( ). Figure S9-8. Observed and simulated isotopic distributions (overlaid). HRMS: m/z found (calcd) for [C 232 H 174 P 10 Ag 4 ] 4+ ([Ag 4 L 2 + 2PPh 3 ] 4+ ), ( ); [C 116 H 87 P 5 Ag 2 ] 2+ ([Ag 2 L + PPh 3 ] 2+ ), ( ).

16 Figure S9-9. Observed and simulated isotopic distributions. HRMS: m/z found (calcd) for [C 214 H 159 P 9 Ag 4 ] 4+ ([Ag 4 L 2 + PPh 3 ] 4+ ), ( ). Figure S9-10. Observed and simulated isotopic distributions (overlaid). HRMS: m/z observed (simulated) for [C 196 H 144 P 8 Ag 4 ] 4+ ([Ag 4 L 2 ] 4+ ), ( ); [C 98 H 72 P 4 Ag 2 ] 2+ ([Ag 2 L] 2+ ), ( ).

17 Luminescence study Table S4. Fluorescence lifetime data of Ag 4 L 2 cage in solution and in solid state, Ag 4 L 2 -dppb wet gel, AgL-dppb-I crystals and Ag 2 I 2 (dppb) 2 crystals (The resulting signals were fitted with a double exponential decay function, which obtained the best fit with respect to both the recorded phase and intensity information). Ag 4 L 2 cage [d] In CHCl 3 ( mol L -1 ) Sample 1 /ns [a] A 1 [b] 2 /ns [a] A 2 [b] /ns [c] Solid Ag 4 L 2 -dppb gel Wet gel [a] AgL-dppb-I Crystals Ag 2 I 2 (dppb) 2 Crystals Fluorescence lifetime. [b] Fractional contribution. [c] Weighted mean lifetime. [c] Data from ref 1. Table S5. Fluorescence quantum yields of Ag 4 L 2 cage in solution and in solid state, Ag 4 L 2 -dppb wet gel, AgL-dppb-I crystals and Ag 2 I 2 (dppb) 2 crystals. Sample Ag 4 L 2 cage [a] In CHCl 3 ( mol L -1 ) Φ 45% Solid 89% Ag 4 L 2 -dppb gel Wet gel 69% AgL-dppb-I Crystals 72% Ag 2 I 2 (dppb) 2 Crystals 8.5% [a] Data from ref 1. Detection of PA in aqueous phase Fluorescence titration measurements were performed by the gradual addition of a 0.2 mmol L -1 aqueous solution of picric acid (PA) to well-dispersed aqueous suspension of Ag 4 L 2 -dppb gel (100 ml, c(l) = mol L -1 ). A progressive decrease in fluorescence intensity of Ag 4 L 2 -dppb gel was observed upon incremental addition of PA. The quenching efficiency was calculated by using the equation (I 0 I)/I 0 100%, where I 0 and I are the respective fluorescence intensities of Ag 4 L 2 -dppb gel before and after the addition of PA. Fluorescence quenching took place upon the addition of PA (200 μl of 0.2 mmol L -1 ), and PA showed highly significant fluorescence quenching (87%).

18 Absorbance/a.u. The quenching constant of PA were calculated from Stern Volmer (SV) plot in aqueous medium using the SV equation I 0 /I = K SV [A] + 1, where I 0 and I are the fluorescence intensities before and after the addition of the respective analyte, [A] is the molar concentration of the analyte and K SV is the quenching constant. PA resulted in a linear SV plot, indicating the static quenching mechanism is operative at a low concentration range. The linear fitting of the SV plot for PA at the low concentration range (0 14 μmol L -1 ) offered a quenching constant of L mol 1 (R 2 = ). In order to calculate the limit of detection for PA by Ag 4 L 2 -dppb gel, incremental amounts of a very low concentration PA (20 μmol L -1 ) solution were added to the aqueous suspension of Ag 4 L 2 -dppb gel and the fluorescence quenching was monitored. The change in fluorescence intensity versus concentration of PA graph revealed a linear curve with a slope (m) of and correlation coefficient (R 2 ) of The limit of detection (LOD) was calculated by using the equation: LOD = 3σ/m, where σ is the standard deviation of the initial intensity of Ag 4 L 2 -dppb gel without analyte and m denotes the slope of the above-mentioned linear curve. The limit of detection for PA was found to be 39 ppb Wavelength/nm 0 L 1 L 5 L 10 L 20 L 35 L 50 L 75 L 100 L 150 L 200 L 300 L Figure S10. UV-vis spectra of aqueous dispersion of Ag 4 L 2 -dppb gel (c(l) = mol L -1 ) with adding PA solution (0.2 mmol L -1 ) at room temperature.

19 Intensity/a.u. (I 0 /I) c(tnp)/ M Figure S11. Stern Volmer traces of PA (0 200 μl; 0.2 mmol L -1 ) in aqueous dispersion of Ag 4 L 2 -dppb gel (100 ml, c(l) = mol L -1 ). Table S6. Standard deviation for Ag 4 L 2 -dppb gel. Blank readings Fluorescence Intensity Standard deviation (σ) Equation y = a + b*x Pearson's r Adj. R-Square Value Standard Error B Intercept B Slope c/ M Figure S12. Linear region of fluorescence intensity of aqueous dispersion of Ag 4 L 2 -dppb upon addition of PA solution at λ em = 508 nm (λ ex = 440 nm) (R 2 = 0.994). Table S7. Detection limit calculation for Ag 4 L 2 -dppb gel. Slope from graph (m) Detection limit (3σ/m) µm 39 ppb

20 Anion-response study Table S8. The response of Ag 4 L 2 -dppb gel towards various anions (one equivalent of anion with respect to Ag + ). Anion HSO 4 - H 2 PO 4 - HPO 4 2- NO 2 - Response after 16 h Anion AcO - NO 3 - BF 4 - F - Response after 16 h Anion Cl - Br - I - Response after 16 h Reaction conditions: L (27.4 mg, 0.02 mmol) and AgBF 4 (7.8 mg, 0.04 mmol) were mixed in CHCl 3-CH 3CN (1.6 ml, v:v 5:3) in the aid of sonication, and then dppb (17.1 mg, 0.04 mmol) was added to obtain the Ag 4L 2-dppb gel. An aqueous solution of tetrabutylammonium (TBA) salts with various counteranions (0.04 mmol) was layered on top of the gel. The concentration of TBA salt solutions listed is 0.1 mol L -1 except that TBA salt of BF 4 - is not so soluble, and the concentration of BF 4 - solution is 0.05 mol L -1, while other TBA salts with PF 6 -, OTf - and ClO 4 - were not tested due to their poor solubility in water. Table S9. Selected bond lengths (Å) and angles (deg) for AgL-dppb-I. Bond lengths Bond angles Ag(1)-P(2)# (7) P(2)#1-Ag(1)-P(1) (2) Ag(1)-P(1) (8) P(2)#1-Ag(1)-I(2) (18) Ag(1)-I(2) (3) P(1)-Ag(1)-I(2) (18) Ag(1)-I(2)# (3) P(2)#1-Ag(1)-I(2)# (18) I(2)-Ag(1)# (3) P(1)-Ag(1)-I(2)# (18) P(2)-Ag(1)# (7) I(2)-Ag(1)-I(2)# (7) Ag(1)-I(2)-Ag(1)# (7) Symmetry transformations used to generate equivalent atoms: #1 -x+1,-y+1,-z+1.

21 Counts/s Intensity AgL-dppb-I Ag 2 I 2 (dppb) 2 simulated / Figure S13. PXRD patterns of AgL-dppb-I crystals, and Ag 2 I 2 (dppb) 2 crystals synthesized without the Ag 4 L 2 -dppb gel, and simulated pattern from the cif file, and molecular structure of AgL-dppb-I determined by X-ray diffraction I 3d Ag 3d C 1s P 2p Binding energy / ev Figure S14. XPS survey spectrum of AgL-dppb-I crystals (The atomic ratio of P/Ag is 1.9 and that of I/Ag is 0.97).

22 Intensity/a.u Wavelength/nm Figure S15. Photoluminescence spectrum of Ag 2 I 2 (dppb) 2 crystals (λ ex = 359 nm).