Photoinduced Electron Transfer from a Tetrathiafulvalene- Calix[4]pyrrole to a Porphyrin Carboxylate within a Supramolecular

Transcription

1 Supporting Information for: Photoinduced Electron Transfer from a Tetrathiafulvalene- Calix[4]pyrrole to a Porphyrin Carboxylate within a Supramolecular Ensemble Christina M. Davis, Yuki Kawashima, Kei Ohkubo, Jong Min Lim, Dongho Kim,*, Shunichi Fukuzumi,*, and Jonathan L. Sessler*, Department of Chemistry, The University of Texas at Austin, 5 E. 4 th Street-Stop A53, Austin, Texas 787-5, United States Department of Material and Life Science, Graduate School of Engineering, Osaka University, and ALCA, Japan Science and Technology (JST), Suita, Osaka , Japan Department of Chemistry, Yonsei University, Seoul -75, Korea Table of Contents: Absorption spectra (p. S) NMR spectra (p. S3) Density functional theory calculations (p. S3) Fluorescence spectra (p. S4) Phosphorescence spectra (p. S4) Femtosecond transient absorption spectra (p. S5) Nanosecond transient absorption spectra (p. S6) Absorbance titration (p. S8) Electron transfer rate analysis (p. S9) Eyring plot (p. S) Electron spin resonance (p. S) Supporting References (p. S) S

2 Normalized Absorbance (a.u.) Wavelength (nm) 6 7 Figure S. Absorption spectra for (black solid), (purple solid), and 3 (purple dashed) as recorded in PhCN at 98 K.. (! - -) []-![], M 5 x -6 Figure S. Linear plot used to determine binding constant (K a ) corresponding to the interaction of with. This plot is based on the observed changes in absorption as detailed in the text. The slope (K a ) is, ± 4 with an R value of (Note: A was set to.45 ; see main text for definitions.) S

3 Figure S3. H NMR spectra for (a) tetraethylammonium porphyrin carboxylate (.5 mm), (b) : mixture of and, each at.5 mm, (c) calix[4]pyrrole (.5 mm). All spectra were recorded at 98 K in deuterated chloroform. Figure S4. The HOMO (left) and LUMO (right) for the optimized supramolecular ensemble formed upon mixing and (complex 4) as calculated by density functionally theory at the B3LYP/6-3G(d) level. S3

4 Figure S5. (a) Fluorescence spectrum for (5 mm) in PhCN at 98 K; excitation wavelength: 5 nm. (b) Fluorescence decay profiles of the singlet-excited state of ( *) observed upon excitation at 485 nm in the absence (black) and the presence of (.5 mm) (red) in deoxygenated PhCN containing (.3 mm). 3.4x 6 3. Intensity (a.u.) nm Wavelength (nm) Figure S6. Phosphorescence spectrum of recorded in a solution of -methyltetrahydrofuran and ethyl iodide (:), which was then used to form transparent glass upon cooling to T = 77 K where the measurement was made via excitation at 435 nm. S4

5 Figure S7. Femtosecond transient absorption spectra of * recorded after irradiation of (. mm) at 4 nm in deoxygenated PhCN at 98 K. Figure S8. Femtosecond transient absorption features seen upon excitation of (. mm) at 4 nm. The changes shown after the sample is subject to laser pulse in deoxygenated PhCN at 98 K. S5

6 (a) 3 (b)!abs at 67 nm!abs at 67 nm 3 3 Time, ps Time, ps Figure S9. (a) Decay in the absorption intensity of * recorded at 67 nm after excitation at 4 nm. The sample used for the analysis contained.3 mm of. Based on curve fitting, the decay rate was found to be 4.3 x 8 s - with R =.99. (b) Decay of absorption at 67 nm attributed to * as observed post excitation at 4 nm for a sample containing (.5 mm) and (.3 mm). Based on these data, the decay rate was calculated to be s with an R =.99. Both samples were done in deoxygenated benzonitrile at 98 K. These decay rates were collected in the Osaka laboratory and are relatively close to the decay rate found in the Seoul laboratory, namely s as described in the text. The results in this figure reflect experiments carried out at higher concentrations than used in the Seoul laboratory (5 µm for both and ). Figure S. (a) Nanosecond laser flash photolysis absorption profile of 3 * (. mm) as observed µs (black) and µs (red) after excitation at 355 nm in deoxygenated benzonitrile at 98 K. (b) Decay of absorption of 3 * at 45 nm post excitation at 355 nm in benzonitrile at 98 K. Based on curve fitting, the decay rate was found to be. x 4 sec with R =.994 (inset). S6

7 . MTTFuMex355-5mJ-TA µs.8.6!abs Wavelength, nm Figure S. Nanosecond laser flash photolysis absorption spectrum observed upon excitation of (.3 mm) at 355 nm in deoxygenated benzonitrile at 98 K To determine the absorption spectra of the radical anion and the radical cation +, chemical redox processes were carried out while monitoring the changes in the UV Vis NIR spectrum. The chemical oxidant tris(4-bromophenyl)ammoniumyl hexachloridoantimonate, also known as magic blue, was used to induce the radical cation +. The titration with up to equivalent of magic blue is shown in Figure S. The emergence of absorption features at 43, 6, and 93 nm following oxidation of is fully consistent with the oxidation of TTF to TTF +. The naphthalene radical anion was used to reduce porphyrin chemically. The naphthalene radical anion was prepared in deoxygenated, anhydrous tetrahydrofuran (THF) following a literature procedure. The UV spectrum for the titration of with the naphthalene radical anion is shown in Figure S. The absorbance bands for the porphyrin radical anion are centered at 57, 68, and 85 nm. S7

8 . + equiv. oxidant Absorbance (a.u.) nm 6 nm 93 nm Wavelength (nm) Figure S. Titration of (5 mm, black line) with up to equivalent of the chemical oxidant magic blue (final spectrum shown with a red line) at 98 K in benzonitrile. Absorbance (a.u.) nm 68 nm naphth. radical anion (nra) + µl nra + µl nra + 3 µl nra + 4 µl nra + 5 µl nra + 6 µl nra 85 nm Wavelength (nm) 9 Figure S3. Titration of (.3 mm, benzonitrile) with the naphthalene radical anion at 98 K. Shown in this figure are the absorbance spectra of the naphthalene radical anion (black), porphyrin (red), with ml naphthalene radical anion added (red-orange), with ml naphthalene radical anion (orange), with 3 ml naphthalene radical anion (yellow), with 4 ml naphthalene radical anion (green), with 5 ml naphthalene radical anion (blue), and with 6 ml naphthalene radical anion (purple). S8

9 Figure S4. (a) Decay time profiles of absorbance at 67 nm with various laser intensities. Inset: First-order plots. Rate of intramolecular back electron transfer (k BET ) (b) vs laser intensity for a sample containing.3 mm and. mm (left) and (c) vs [] for a sample containing.3 mm (right) in deoxygenated benzonitrile at 98 K. S9

10 (a)! nd-oeder-decay (b)! [BTTFC4P + ], M 6 6 [ + ], M 6 5 µm 4 µm 3 µm µm µm Time, Time, ms ms y =.5e e+6x R =.9858 Figure S5. Second order decay analysis of the back electron transfer process at various concentrations of as studied y =.997e e+6x R = in the presence y =.4e+5 of.3 mm + of 8.678e+5x in deoxygenated R =.9879 benzonitrile at 98 K (left). Rate of back electron transfer versus concentration of y in = 844 a.3 mm e+5x solution of R = in PhCN at 98 K. On the basis of these analyses, the intermolecular y =.3754e e+5x R = electron transfer rate was found to be M sec (right).. ln(k BET T, s K ) T, K Figure S6 Eyring plot constructed by plotting the observed changes in the rate of back electron transfer (k BET ) versus temperature in benzonitrile. The concentrations of and were.3 mm and. mm, respectively. ΔG was found to be 4 kcal mol, ΔS to be 4 cal K mol, and ΔH to be.9 kcal mol. S

11 5 + g =.67 - g = Field Strength (mt) Figure S7. Normalized ESR spectra for chemically induced BTTF-C4P ( + ) and porphyrin carboxylate ( ) in deaerated PhCN at 77 K. Supporting References () Park, J. S.; Karnas, E.; Ohkubo, K.; Chen, P.; Kadish, K. M.; Fukuzumi, S.; Bielawski, C. W.; Hudnall, T. W.; Lynch, V. M.; Sessler, J. L. Ion-Mediated Electron Transfer in a Supramolecular Donor-Acceptor Ensemble. Science, 39, () Corey, E. J.; Gross, A. W. tert-butyl-tert-octylamine. Org. Synth. 987, 65, S