S1. 1 H NMR spectrum for PTTBD in CDCl 3. Insert shows the expansion of the aromatic region and the sharp proton resonances.

Transcription

1 Supporting Information Tuning the Förster Overlap Integral: Energy Transfer over 20 Angstroms from a Pyrene-based Donor to Borondipyrromethene (Bodipy) Dan Bai, Andrew C. Benniston, Jerry Hagon, Helge Lemmetyinen, ikolai V. Tkachenko and Ross W. Harrington Contents S1. 1 H MR spectrum for PTTBD in CDCl 3. Insert shows the expansion of the aromatic region and the sharp proton resonances. S2. Selected molecular orbitals calculated for PT using Gaussian 03 and DFT (B3LYP) and the 6-311G basis set. Energy given in ev. S3. ormalised room temperature absorption profiles recorded for PT (black), BD (green) and PTTBD (red) in MeTHF. S4. Absorption spectra for BD in a range of solvents. S5. ormalised fluorescence profiles recorded for PT in MeC (black), CHX (dash), MeTHF (dot) and DCE (dash dot). Abbreviations defined in the main text. S6. ormalised absorption (black) and fluorescence excitation spectrum (red) for PTTBD in MeTHF. S7. ormalised absorption (black) and fluorescence excitation spectrum (red) for PTTBD in cyclohexane. S8. ormalised absorption (black) and corrected fluorescence excitation spectrum (red) for PTTBD in DMSO. S9. Time-correlated single photon counting profile recorded for PT in THF showing the least-sqaures fit (red line) and instrument response function. S10. Plot for the rise-time ( RIS ) for the single-photon-counting data with the solvent viscosity. Red line represents the least-squares fit to the data points. S11. Plot for the radiative rate constant (k RAD ) versus n 2 for PT in a range of solvents. Blue line represents the least-squares fit to the data points ( ). The two anomalous data points are shown ( ). S12. The spectral overlap regions (yellow) from the normalised emission for PT and absorption for BD in DMSO. S13. The spectral overlap regions (yellow) from the normalised emission for PT and absorption for BD in DMF. S14. The spectral overlap regions (yellow) from the normalised emission for PT and absorption for BD in THF. S15. Top: Transient absorption profiles recorded after excitation of PTTBD in CHX with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. Bottom: Kinetic traces at two different probe wavelengths and the least-squares fit to the data points (red). S16. Top: Transient absorption profiles recorded after excitation of PTTBD in DCE with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. Bottom: Kinetic traces at two different probe wavelengths and the least-squares fit to the data points (red).

2 S17. Top: Transient absorption profiles recorded after excitation of PTTBD in MeC with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. Bottom: Kinetic traces at two different probe wavelengths and the least-squares fit to the data points (red). S18.Component differential absorption spectra recorded for PTTBD in toluene following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. S19.Component differential absorption spectra recorded for PTTBD in THF following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. S20.Component differential absorption spectra recorded for PTTBD in Et 2 O following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. S21.Component differential absorption spectra recorded for PTTBD in methoxybenzene following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. S22.Component differential absorption spectra recorded for PTTBD in MeC following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. S23.Component differential absorption spectra recorded for PTTBD in DCE following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. S24.Component differential absorption spectra recorded for PTTBD in cyclohexane following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. S25. Variation of the ratio of the rate for energy transfer and the radiative rate of the donor versus the overlap integral. S26. Apparent inverse relationship between k EET and 1/n 4 for low polarity solvents ( ) and high polarity solvents ( ). Table S1. Values for measured rates of energy transfer and solvent parameters. Table S2. Calculated parameters using the Förster equation assuming 2 = 2/3 and intramolecular distances R.

3 S1. Room temperature 1 H MR spectrum for PTTBD in CDCl 3. Insert shows the expansion of the aromatic region and the sharp proton resonances.

4 S2. Selected molecular orbitals calculated for PT using Gaussian 03 and DFT (B3LYP) and the 6-311G basis set. Energy given in ev.

5 ormalised Absorbance MeTHF Wavelength / nm S3. ormalised room temperature absorption profiles recorded for PT (black), BD (green) and PTTBD (red) in MeTHF. ote: The small differences seen between PT and PTTBD for the pyrene-thiophene segment are a result of the triazole group which slightly perturbs the electronics of the system.

6 max / M-1 cm Black = toluene Red = MeTHF Green = MeC Blue = DCE Cyano = Cyclohexane B F F Wavelength / nm Table Solvent MAX M -1 cm -1 Toluene 78,500 MeTHF 72,000 MeC 72,900 DCE 73,850 Cyclohexane 79,550 S4. Absorption spectra for BD in a range of solvents.

7 ormalised Intenisty Wavelength / nm S5. ormalised fluorescence profiles recorded for PT in MeC (black), CHX (dash), MeTHF (dot) and DCE (dash dot). Abbreviations defined in the main text.

8 ormalised Intensity 1.0 MeTHF S 0.8 F B F Abs Wavenumber / cm -1 Exc S6. ormalised absorption (black) and corrected fluorescence excitation spectrum (red) for PTTBD in MeTHF.

9 ormalised Intensity 1.0 CX S 0.8 F B F Abs Exc Wavenumber / cm -1 S7. ormalised absorption (black) and corrected fluorescence excitation spectrum (red) for PTTBD in cyclohexane.

10 ormalised Intensity 1.0 DMSO S 0.8 F B F Wavenumber / cm -1 Abs Exc S8. ormalised absorption (black) and corrected fluorescence excitation spectrum (red) for PTTBD in DMSO.

11 Counts THF R S Time / ns S9. Time-correlated single photon counting profile recorded for PT in THF showing the least-sqaures fit (red line) and instrument response function.

12 rise / ps slope = 58 ps cp Viscosity / cp S10. Plot for the rise-time ( RIS ) for the single-photon-counting data with the solvent viscosity. Red line represents the least-squares fit to the data points.

13 R S k RAD 10 8 s DMSO DMF n 2 S11. Plot for the radiative rate constant (k RAD ) versus n 2 for PT in a range of solvents. Blue line represents the least-squares fit to the data points ( ). The two anomalous data points are shown ( ).

14 S12. The spectral overlap regions (yellow) from the normalised emission for PT and absorption for BD in DMSO.

15 S13. The spectral overlap regions (yellow) from the normalised emission for PT and absorption for BD in DMF.

16 S14. The spectral overlap regions (yellow) from the normalised emission for PT and absorption for BD in THF.

17 A A A Black 1.8ps Red 2.1ps Green 3.5ps Blue 6.7ps Cyano 14.7ps Pink 34.5ps Yellow 356ps S B F F Wavelength / nm Cyclohexane (532 nm) = 6.4 ps B F F S Time / ps Cyclohexane (745 nm) = 5.8 ps B F F Time / ps S S15. Top: Transient absorption profiles recorded after excitation of PTTBD in CHX with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. Bottom: Kinetic traces at two different probe wavelengths and the least-squares fit to the data points (red).

18 A A A Black 1.7ps Red 2.5ps Green 5ps Blue 27ps Cyano 277ps DCE S B F F Wavelength / nm DCE (733 nm) = 2.7 ps B F F Time / ps S DCE (533 nm) = 2.3 ps Time / ps S B F F S16. Top: Transient absorption profiles recorded after excitation of PTTBD in DCE with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. Bottom: Kinetic traces at two different probe wavelengths and the least-squares fit to the data points (red).

19 A A A Black 1.8ps Red 2.3ps Blue 2.9ps Green 5.1ps Cyano 7.8ps Pink 12.5ps Yellow 100ps MeC S B F F Wavelength / nm MeC (743 nm) = 2.6 ps B F F S Time / ps = 2.4 ps MeC (524 nm) Time / ps S B F F S17. Top: Transient absorption profiles recorded after excitation of PTTBD in MeC with a 70 fs laser pulse delivered at 400 nm. Time delays are shown. Bottom: Kinetic traces at two different probe wavelengths and the least-squares fit to the data points (red).

20 A Toluene Red = 1.8 ps Blue = 5.1 ps Green = 2.4 ns Wavelength / nm S18.Component differential absorption spectra recorded for PTTBD in toluene following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown.

21 A THF Blue = 2.9 ps Red = 21.6 ps Green = 2.4 ns Wavelength / nm S19.Component differential absorption spectra recorded for PTTBD in THF following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown.

22 A Et 2 O Blue = 4.6 ps Red = 1.5 ps Green = 2.4 ns Wavelength / nm S20.Component differential absorption spectra recorded for PTTBD in Et 2 O following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown.

23 A 0.2 Anisole Red = 2.3 ps Blue = 5.8 ps Green = 3 ns Wavelength / nm S21.Component differential absorption spectra recorded for PTTBD in anisole following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown.

24 A MeC Red = 55 ps Blue = 2.5 ps Green = 3.4 ns Wavelength / nm S22.Component differential absorption spectra recorded for PTTBD in MeC following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown.

25 A DCE Red = 200 ps Blue = 3.1 ps Green = 2.2 ns Wavelength / nm S23.Component differential absorption spectra recorded for PTTBD in DCE following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown.

26 A CHX Blue = 7.5 ps Red = 2.6 ps Green = 1.8 ns Wavelength / nm S24.Component differential absorption spectra recorded for PTTBD in cyclohexane following excitation with a 70 fs laser pulse delivered at 400 nm. Time delays are shown.

27 k EET /K RAD J F mmol -1 cm 6 S25. Variation of the ratio of the rate for energy transfer and the radiative rate of the donor versus the overlap integral. Values for k RAD are taken from S10.

28 Table S1. Values for measured rates of energy transfer and solvent parameters. Solvent k EET / s -1 a k EET /k RAD n 1/n 4 F b MEB MeTHF DCE CHX ~0 TOL THF DEE DMF DMSO MeC a Average value. b Pekar function (see below) 2 s 1 n F 2 s 1 2n 2 1 1

29 4.0 MeC 3.5 k EET s /n 4 S26. Apparent inverse relationship between k EET and 1/n 4 for low polarity solvents ( ) and high polarity solvents ( ).

30 Table S2. Calculated parameters using the Förster equation assuming 2 distances R as shown in Figure 1 below. a = 2/3 and intramolecular Solvent R o / Å b k EET / s -1c k EET / s -1d k EET / s -1e R / Å f MEB MeTHF DCE CHX TOL DMF DMSO THF DEE MeC Average 13.8 a Other parameters taken from Tables in manuscript. b Förster distance c Rate for electronic energy transfer assuming R = Å. d Rate for electronic energy transfer assuming R = 20.1Å. e Rate for electronic energy transfer assuming R = 16.0Å. (see below). f Calculated distance over which EET is transferred using Equation 1 and experimental k EET values: Ro (Eq.1) R 1/6 k EET D The calculated distance R is situated in between the pyrene and thiophene unit, which is reasonable considering that the exciplex-like state comprises (pyr + --thio - ) *.

31 Figure 1. Computer calculated structure for PTTBD and selected intramolecular distances.