Enhancing Fluorescence of Naphthalimide Derivatives by Suppressing the Intersystem Crossing

Transcription

1 Supporting information Enhancing Fluorescence of Naphthalimide Derivatives by Suppressing the Intersystem Crossing Wenqiang Zhang,,, Yuwei Xu,, Muddasir Hanif, Shitong Zhang, Jiadong Zhou, Dehua Hu,*, Zengqi Xie, Yuguang Ma*, State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun , P. R. China Institute of Polymer ptoelectronic Materials and Devices, State Key Laboratory ofluminescent Materials and Devices, South China University of Technology,Guangzhou , P. R. China. Synthesis of NMIs... 3 Thermal properties of Ph-NMI and TPA-NMI... 5 Photograph of NMIs under UV-light radiation... 5 PL quantum efficiency of NMI films... 6 Lifetime measurement of TPA-NMI... 6 X-ray Crystallography of Ph-NMI and TPA-NMI derivatives Cyclic voltammetry of Ph-NMI and TPA-NMI Frontier orbital distribution calculation... 9 Energy landscape of singlet and triplet of TPA-NMI LED performance of TPA-NMI LED performance of NMIs withoutdoping S1

2 NMR spectra of Ph-NMI and TPA-NMI Chemical structures of NPB, MADN, mcp, TCTA, TPBi Reference S2

3 Synthesis of NMIs Br i Br N ii 3 H B H N Ph-NMI 1 2 N N N B TPA-NMI i: acetic acid, 80 C; 20 h; ii:pa(pph3)4, K2C3(2 M aq), toluene, H2, ethanol, 90 C, 24 h; SchemeS1. Synthesis procedure and chemical structures of Ph-NMI and TPA-NMI. 4 Synthesis of Br-NMI (2): 500 mg (1.81 mmol) 4-Bromo-1,8-naphthalic anhydride (Compound 1), 500 mg (2.17 mmol) 2,6-diisopropylphenylamine were added into 15 ml glacial acetic acid, and then refluxed for 24 hours at 120 C. After that, the reaction mixture was cooled to room temperature and dropped into 100 ml water and filtrated. Washed with saturated NaHC 3 solution, water and CH 3 H (30 ml 3 times) subsequently. The solid was purified by column chromatography. Yield: 86%. 1 H NMR(500 MHz,CDCl 3,δ): (d, 1H, ArH), (d, 1H, ArH), (d, 1H, ArH), (d, 1H, ArH), (t, 1H, ArH), (t, 1H, ArH), (d, 2H, ArH), (m, 2H, CH), (d, 12H, CH 3 ), MS (ESI): MW 436.3, m/z (M + ). Synthesis of Ph-NMI: A portion of 300 mg (0.69 mmol) compound 2, mg (1.38 mmol) phenylboronic acid, 1.38 g anhydrous potassium carbonate was added into 10 ml depurated toluene, 5 ml water and 2 ml ethanol. Degassed with inert gas totally and then added 40 mg tetrakis(triphenylphosphine)palladium(0). The temperature was elevated up to 90 C. the mixture was heated for 24 hours. After cooled to room temperature, the obtained mixture was poured into 100 ml water and stirred for half an hour, then extracted with CHCl 3. The organic phase was treated with anhydrous Na 2 S 4 to remove the residual water. Purified by column chromatography. Yield: 70%. 1 H NMR(500 MHz,CDCl 3,δ):8.72 (t, J = 7.5 Hz, 2H), 8.36 (d, J = 10 Hz, 1H), S3

4 7.76 (t, J = 7.5 Hz, 2H), 7.58 (m, J =5.0 Hz, 5H), 7.49 (t, J = 10.0 Hz, 1H), 7.35 (d, J = 5.0 Hz, 2H), 2.79 (m, J = 5.0 Hz, 2H), 1.18 (d, J = 5.0 Hz, 12H), 13 C NMR (100 MHz, CDCl 3, δ): , , , , , , , , , , , , , , , , , , , , 29.13, HRMS (ESI): m/z calcd for C 30 H 27 N 2 : [M] + ; found: Synthesis of TPA-NMI: A portion of 2.18 g (5 mmol) compound 2, 1.47 g (4 mmol) 4-(Diphenylamino)phenylborate, 8.28 g anhydrous potassium carbonate was added into 60 ml depurated toluene, 30 ml water and 10 ml ethanol. Degassed with inert gas totally and then added 150 mg tetrakis(triphenylphosphine)palladium(0) and refluxed at 90 C for 24 hours. After cooled to room temperature, the obtained mixture was poured into 100 ml water and stirred for half an hour, then extracted with CHCl 3. The organic phase was treated with anhydrous Na 2 S 4 to remove the residual water. Purified by column chromatography. Yield: 80%. 1 H NMR(500 MHz,CDCl 3,δ):8.70 (d, J = 5.0 Hz, 2H), 8.50 (d, J = 10 Hz, 1H), 7.78 (t, J = 7.5 Hz, 2H), 7.48 (t, J =5.0 Hz, 1H), 7.41 (d, J = 5.0 Hz, 2H), 7.34 (m, J = 5.0 Hz, 6H), 7.24 (m, J = 5.0 Hz, 6H), 7.11 (t, J = 5.0 Hz, 2H), 2.79 (m, J = 5.0 Hz, 2H), 1.18 (d, J = 5.0 Hz, 12H), 13 C NMR (100 MHz, CDCl 3, δ): , , , , , , , , , , , , , , , , , , , , , , , 29.12, HRMS (ESI): m/z calcd for C 42 H 36 N 2 Na 2 : [M+Na] + ; found: S4

5 Thermal properties of Ph-NMI and TPA-NMI (a) (b) Exothermic 97.3 Exothermic Temprature / C Temprature / C (c) Weight /% Ph-NMI TPA-NMI Temperature / C Figure S1. DSC curves of a)ph-nmi and b) TPA-NMI, measured under nitrogen flowat a heating rate of 10 C min -1 and a cooling rate of 5 C min -1. c) TGA curves of Ph-NMI and TPA-NMI derivatives, measured under nitrogen flow (20 ml min -1 ) at a heating rate of 10 C min -1. Photograph of NMIs under UV-light radiation Figure S2. Photographs of Ph-NMI and TPA-NMI derivatives under UV-light radiation. S5

6 PL quantum efficiency of NMI films Table S1. Summary of PL quantum efficiency of NMI films Ph-NMI TPA-NMI No-doping 14.9% 31.1% Doping (PMMA 2%) 26.2% 67.8% Lifetime measurement of TPA-NMI 100k 10k TPA-NMI IRF τ F = 6.9 ns Counts (cps) 1k Time (ns) Figure S3. Lifetime measurement of TPA-NMI. (Irradiation wavelength: 420 nm) X-ray Crystallography of Ph-NMI and TPA-NMI derivatives. The intensity data for the single crystal X-ray diffraction analysis of two molecules were collected at room temperature on diffractometer using CuKa radiation (λ= Å). Data collection was performed with CLLECT cell refinement and data reduction with DENZ/SCALEPACK. The structure was solved with SHELXL2014 was used for full matrix least squares refinement. The H-atoms were then introduced at idealized positions and constraint to their parent atom during thelast refinements. Graphics were generated with MERCURY 2.4.CCDC and CCDC contain the supplementary crystallographic data for the two S6

7 compounds. The data can be obtained free of charge via Figure S4. Molecular structure and packing structure of Ph-NMI (a) and TPA-NMI (b) in single crystals. Table S2 Crystal data and structure refinement for Ph-NMI and TPA-NMI, respectively. CDE NAME Ph-NMI TPA-NMI Empirical formula C 30 H 27 N 2 C 42 H 36 N 2 2 Formula weight Temperature (K) 293(2) 150(2) Wavelength (Å) Crystal system Tetragonal Tetragonal Space group P-43 P-42/n Unit cell dimensions a (Å) (2) (4) b (Å) (2) (4) c (Å) (10) (3) α ( o ) β ( o ) γ ( o ) Volume (Å 3 ) (14) (3) S7

8 Z, density-diffrn (mg/m 3 ), R(%) 4, 1.210, , 1.220, 2.37 Absorption Coefficient (mm -1 ) F (000) Theta ranges for data collection ( o ) Limiting indices R indices (all data) -11<=h<=10-8<=k<=11-32<=l<=26 R 1 =0.0383, wr 2 = <=h<=14-27<=k<=27-14<=l<=14 R 1 =0.0559, wr 2 = Goodness-of-fit on F Cyclic voltammetry of Ph-NMI and TPA-NMI. The electrochemical properties of Ph-NMI and TPA-NMI were investigated by the cyclic voltammetry (CV) method as shown in Figure S5. From the spectra, the highest occupied molecular orbital (HM) and the lowest unoccupied molecular orbital (LUM) energy levels could be calculated from the onset of the oxidation and reduction potentials with regard to the energy level of ferrocene. Ph-NMI possessed a HM level of ev while TPA-NMI possessed an energy level of 5.33 ev. This difference could be attributed to the different electronic structures of NMIs derivatives with different donor unit. Current (a.u.) Ph-NMI TPA-NMI Potential versus Ag/Ag + / V Figure S5. Cyclic voltammograms of NMIs. Solvent: CH 2 Cl 2, 0.1 mol L -1 n-bu 4 NPF 6, S8

9 298 K, Fc/Fc +. Frontier orbital distribution calculation In order to deeply understand the electronic structures at molecular level, density functional theory (DFT) calculations (B3LYP/6-31G (d)) were carried out as shown in Figure S6. Matched with CV data, electrons of LUM were mainly located on the naphthalene skeleton for both compounds. For HM distribution, the electrons of TPA-NMI were located on the donor triphenylamine unit, while electrons of Ph-NMI were distributed on the naphthalene ring and N-substituent phenyl ring, totally different with TPA-NMI compound. The HM and LUM energy calculated by DFT were matched well with that from CV characterization. Figure S6. Calculated spatial distributions of the HM and LUM of Ph-NMI and TPA-NMI. Figure S7. Natural transition orbitals for S 0 S 2 excitation for the H-NMI. S9

10 Energy landscape of singlet and triplet of TPA-NMI. Excitation Energy (ev) Energy of singlet and triplet (TD-DFT M06-2X) S 2 S 1 hν "hot exciton" RISC T 3 T 2 T 1 (T 4 ) TPA-NMI Figure S8. The energy landscape of singlet and triplet excited states from TD-DFT calculations of TPA-NMI molecule. The high exciton utilizing efficiency (EUE) in TPA-NMI may be explained by its special energy levels arrangement in excited state, in which the reverse intersystem crossing (RISC) from upper triplet levels to the singlet manifold can occur. As shown in Figure S8, the energy levels of T 2 ~T 4 are very close to that of S 1, while a relative large energy gap between T 2 ~T 4 and T 1. In this situation, RISC processes from T 2 ~T 4 to S 1 can compete with the internal crossing (IC) from T 2 ~T 4 to T 1. Therefore, possible RISC from T 2 ~T 4 to S 1 may be expected. This phenomenon has been proposed in some previous reports by our group. [S1-S4] Table S3. Energy levels details of singlet and triplet states of TPA-NMI and Ph-NMI, respectively. TPA-NMI States Energy (ev) scilator Strength States Energy (ev) S T S T S T S10

11 S T S T S T S T S T S T S T Ph-NMI States Energy (ev) scilator Strength States Energy (ev) S T S T S T S T S T S T S T S T S T S T S11

12 LED performance of TPA-NMI Electroluminance (cd m -2 ) Current Density (ma cm -2 ) Figure S9. Electroluminance under different current densities in TPA-NMI. Good linear relationship is observed that no TTA process exists in the EL device. [S5] LED performance of NMIs withoutdoping (a) Current Density (ma cm -2 ) Voltage(V) Luminance (cd m -2 ) (b) LE (cd A -1 ) Luminance (cd m -2 ) 2 1 EQE (%) (c) EL intensity(a.u.) nm Wavelength (nm) Figure S10. Current density-voltage-brightness (J-V-L) characteristics (a), current efficiency and external quantum efficiency versus brightness curves (b) and (c) EL S12

13 spectra recorded at 100 cd m -2 for Ph-NMI derivative without doping device; Table S4. EL performance of TPA-NMI without doping. No-dopi ng V on L max CE max PE max EQE max at 100 cd m -2 (V) (cd m -2 ) (cd A -1 ) (lm W -1 ) (%) V CE EQE (V) (cd A -1 ) (%) CIE (x,y) (0.262,0.216) (a) Current Density (ma cm -2 ) Voltage (V) Luminance (cd m -2 ) (b) LE (cd A -1 ) Luminance (cd m -2 ) EQE (%) Luminance (cd m -2 ) (c) 1.0 EL intensity(a.u.) nm Wavelength (nm) Figure S11. Current density-voltage-brightness (J-V-L) characteristics (a), current Wavelength (nm) efficiency and external quantum efficiency versus brightness curves (b) and EL spectra recorded at 100 cd m -2 for TPA-NMI derivative without doping device. Table S5. EL performance of Ph-NMI without doping. S13

14 NMR spectra of Ph-NMI and TPA-NMI. Figure S12. 1 H NMR (600 MHz, CDCl3) of Ph-NMI. Figure S C NMR (150 MHz, CDCl3) of Ph-NMI. S14

15 Figure S14. 1 H NMR (600 MHz, CDCl3) of TPA-NMI. Figure S C NMR (150 MHz, CDCl3) of TPA-NMI. Chemical structures of NPB, MADN, mcp, TCTA, TPBi. Chart S1. Chemical structure of NPB, MADN, mcp, TCTA, TPBi. S15

16 Reference (S1). Li, W. J.; Pan, Y. Y.; Xiao, R.; Peng, Q. M.; Zhang, S. T.; Ma, D. G.; Li, F.; Shen F. Z.; Wang, Y. H.; Yang, B. et al. Adv. Funct. Mater., 2013, DI: /adfm (S2). Li, W. J.; Liu, D. D; Shen, F. Z.; Ma, D. G; Wang, Z. M.; Feng, T.; Xu, Y. X.; Yang, B.; Ma, Y. G. Adv. Funct. Mater. 2012, 22, (S3). Peng, Q. M.; Li, W. J.; Zhang, S. T.; Chen, P.; Li, F.; Ma, Y. G. Adv.pt. Mater. 2013, 1, (S4). Yao, L.; Zhang, S. T.; Wang, R.; Li, W. J.; Shen, F. Z; Yang, B.; Ma, Y. G. Angew. Chem. Int. Ed., 2014, 53, (S5). Nakagawa, T.; Ku, S. Y.; Wong, K. T.; Adachi, C. Chem. Commun. 2012, 48, S16