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1 upporting Information Impact of ubstituents on Excited tate and Photosensitizing Properties in Cationic Iridium(III) Complexes with Ligands of Coumarin 6 hin-ya Takizawa,*, aoya Ikuta, Fanyang Zeng, hohei Komaru, hinogu ebata and higeru Murata*, Department of Basic cience, Graduate chool of Arts and ciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo , Japan Graduate chool of cience, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo , Japan. * Corresponding author. Tel.: ; fax: ctaki@mail.ecc.u-tokyo.ac.jp, cmura@mail.ecc.u-tokyo.ac.jp 1

2 IrCl 3 3H Ethoxyethanol/ H 2 44 h, 110 o C Ir Cl Cl Ir Dimer 7 (69%) Dimer 7 R 2 R 1 + Cl - R 2 R 2 R 1 R 1 Ir Ethylene glycol H 4 PF 6 R R 1 2~48 h, 150 o C 2 Ir R 2 + PF6 - R 2 R 1 R 1 2 (R 1 = Me, R 2 = H): 58% 3 (R 1 = H, R 2 = Me): 64% 4 (R 1 = Me, R 2 = H): 50% 5 (R 1 = CF 3, R 2 = H): 38% Dimer 7 H H MeH/CH 2 Cl 2 2 h, reflux Ir + Cl - H H H 4 PF 6 Ir + PF6 - H H 6: 79% cheme 1. ynthetic schemes of complexes 2 6 ε x 10-5 /M -1 cm CH2Cl2 2 Cl 2 CH3C 3 C Intensity /a. u Wavelength /nm Figure 1. UV-vis absorption and emission spectra of coumarin 6 in CH 2 Cl 2 and CH 3 C. 2

3 Table 1. Photophysical properties of coumarin 6 in CH 2 Cl 2 and CH 3 C olvent λ abs /nm (ε /M -1 cm -1 ) a λ em /nm b Φ c τ /ns d k r /s -1 e k nr /s -1 f CH 2 Cl (52,600), 463 (52,900) CH 3 C 457 (52,600) a Absorption maxima (molar extinction coefficient) in the visible region. b Emission maximum. c Emission quantum yield measured in deaerated solution. d Emission lifetime measured in deaerated solution. e Radiative rate constant. f onradiative rate constant. Figure 2. Cyclic voltammogram of complex 1 (Inset: CV recorded in a different sweep range). Figure 3. Cyclic voltammogram of complex 2 (Inset: CV recorded in a different sweep range). 3

4 Figure 4. Cyclic voltammogram of complex 3 (Inset: CV recorded in a different sweep range). Figure 5. Cyclic voltammogram of complex 4 (Inset: CV recorded in a different sweep range). Figure 6. Cyclic voltammogram of complex 5 (Inset: CV recorded in a different sweep range). 4

5 Figure 7. Cyclic voltammogram of complex 6 (Insets: CVs recorded in different sweep ranges). Figure 8. DFT-optimized structure of [Ir(ppy) 2 (bpy)] + depicted by ball-and-stick and space-filling models from different angles. Table 2. The higher energy singly occupied molecular orbital (HM) surfaces, the lower energy singly occupied molecular orbital (LM) surfaces, and spin density distributions for the calculated triplet LMCT states of complexes

6 Table 3. M distributions obtained from the DFT-optimized structures of ground-state Ir(III) complexes 1 6 (B3LYP /6-31G(d) on all the non-metal atoms and LAL2DZ on the Ir atom) L L+7 L+6 L+5 L+4 L+3 L+2 L+1 LUM HM H-1 H-2 H-3 H-4 H-5 6

7 (a) P + /P* Co II /Co I Co III /Co II -7 V vs. Fc + /Fc HAsc/HAsc P + /P P/P Co II /Co I Co III /Co II -7 V vs. Fc + /Fc HAsc/HAsc P*/P Figure 9. Redox potential diagrams of the oxidative (a) and reductive quenching pathways. Redox potentials of ascorbate and Co(dmgH) 2 pycl were obtained from references. 1,2 Excited-state reduction potentials E red * (P*/P ) were estimated using E red * = E red 1/2 + E 0-0, where E 0-0 denotes triplet energy estimated from the highest energy 0-0 peak of phosphorescence at 77 K. Excited-state oxidation potentials E ox * (P + /P*) were estimated using E ox * = E ox 1/2 E

8 Photon counts (a) Asca 0 M 0.02 M M 0.05 M τ 0 /τ y = x R² = Time /ns [HAsca] /M Figure 10. Quenching of phosphorescence of complex 1 by HAsca in deaerated CH 3 C acetate/acetic acid buffer (1:1 v/v). (a) Decay profiles of the phosphorescence (590 nm, λ ex = 470 nm) at various concentrations of HAsca. tern Volmer plot for quenching of the phosphorescence by HAsca using the lifetime. The least-squares analysis of the plot yields a quenching constant, k q τ 0, of 11.6 M 1. Photon counts (a) Co(dmgH) 2 pycl 0 mm mm mm 9 mm τ 0 /τ y = x R² = Time /ns Figure 11. Quenching of phosphorescence of complex 1 by Co(dmgH) 2 pycl in deaerated CH 3 C acetate/acetic acid buffer (1:1 v/v). (a) Decay profiles of the phosphorescence (590 nm, λ ex = 470 nm) at various concentrations of Co(dmgH) 2 pycl. tern Volmer plot for quenching of the phosphorescence by Co(dmgH) 2 pycl using the lifetime. The least-squares analysis of the plot yields a quenching constant, k q τ 0, of 477 M [Co] /mm 8

9 Photon counts (a) Asca 0 mm 4.76 mm 9.09 mm 13.0 mm Time /ns τ 0 /τ y = x R² = [HAsca] /mm Figure 12. Quenching of phosphorescence of complex 4 by HAsca in deaerated CH 3 C acetate/acetic acid buffer (1:1 v/v). (a) Decay profiles of the phosphorescence (585 nm, λ ex = 470 nm) at various concentrations of HAsca. tern Volmer plot for quenching of the phosphorescence by HAsca using the lifetime. The least-squares analysis of the plot yields a quenching constant, k q τ 0, of 109 M 1. Photon counts (a) Co(dmgH) 2 pycl 0 mm mm mm mm Time /ns Figure 13. Quenching of phosphorescence of complex 4 by Co(dmgH) 2 pycl in deaerated CH 3 C acetate/acetic acid buffer (1:1 v/v). (a) Decay profiles of the phosphorescence (585 nm, λ ex = 470 nm) at various concentrations of Co(dmgH) 2 pycl. tern Volmer plot for quenching of the phosphorescence by Co(dmgH) 2 pycl using the lifetime. The least-squares analysis of the plot yields a quenching constant, k q τ 0, of M 1. τ 0 /τ y = x R² = [Co] /mm 9

10 upporting information on the quenching efficiency η q, which is the fraction of the sensitizer excited states (P*) quenched by HAsca or Co(dmgH) 2 pycl k q [HAsc ] η q,asc = kr + k nr +k q [HAsc ] + k q '[Co III ] k q (k r + k nr ) 1 [HAsc ] = 1 + kq (k r + k nr ) 1 [HAsc ] + k q '(k r + k nr ) 1 [Co III ] = k q τ 0 [HAsc ] 1 + k q τ 0 [HAsc ] + k q 'τ 0 [Co III ] K V [HAsc ] = 1 + KV [HAsc ] + K V '[Co III ] η q,co = k q '[Co III ] k r + k nr +k q [HAsc ] + k q '[Co III ] k q '(k r + k nr ) 1 [Co III ] = 1 + kq (k r + k nr ) 1 [HAsc ] + k q '(k r + k nr ) 1 [Co III ] = k q 'τ 0 [Co III ] 1 + k q τ 0 [HAsc ] + k q 'τ 0 [Co III ] K V '[Co III ] = 1 + KV [HAsc ] + K V '[Co III ] P hν P* k q [HAsc ] P + HAsc k nr k r k q '[Co III ] P P P + + Co II 10

11 Absorbance h 10 min 20 min 30 min 1 h 1.5 h 2 h 3 h Wavelength /nm Figure 14. Changes in the absorption spectra during the visible-light-driven H 2 generation using complex 4 as the sensitizer. Conditions: HAsca (100 mm)/ir complex 4 (20.5 µm)/ Co(dmgH) 2 pycl (335 µm) in CH 3 C acetate/acetic acid buffer solution (1:1 v/v, 3 ml), λ > 440 nm. This Figure indicates that complex 4 is stable in this reaction. The appearance of absorption at 346 nm is probably due to a compound derived from dehydroascorbate. 3 (a) Figure 15. (a) EI-TF mass spectrum of complex 2 and its simulated isotope pattern. 11

12 (a) Figure 16. (a) EI-TF mass spectrum of complex 3 and its simulated isotope pattern. (a) Figure 17. (a) EI-TF mass spectrum of complex 4 and its simulated isotope pattern. 12

13 (a) Figure 18. (a) EI-TF mass spectrum of complex 5 and its simulated isotope pattern. (a) Figure 19. (a) EI-TF mass spectrum of complex 6 and its simulated isotope pattern. 13

14 References (1) jus, D.; Kelly, P. M. Biochim. Biophys. Acta, 1993, 1144, (2) Du, P.; chneider, J.; Luo, G.; Brennessel, W. W.; Eisenberg, R. Inorg. Chem. 2009, 48, (3) Tanaka, H.; Kimoto, E. Bull. Chem. oc. Jpn. 1990, 63,