Electronic Supplementary Information (ESI)

Electronic Supplementary Information (ESI)

One- and two-photon solvatochromism of the fluorescent dye

Nile Red and its CF3, F and Br-substituted analogues

Mick Hornum,

_{* Peter Reinholdt,}

_{Jan K. Zaręba,}

_{Brian Bjarke Jensen,}

Daniel Wüstner,

_{Marek Samoć,}

_{Poul Nielsen}

_{and Jacob Kongsted}

a_{Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.} b_{Advanced Materials Engineering and Modelling Group, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 29,}

50-370 Wrocław, Poland. c_{Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55,}

DK-5230 Odense M, Denmark. *e-mail: [email protected]

Table A1. Photophysical properties of Nile Red (NR) and the five analogs 1–5. ... 2

Figure A1. Normalized absorption (green) and fluorescence (orange) spectra for Nile Red (NR) and the five analogs 1–5 at concentrations of 3.0 μM in the following six solvents with relative polarities given in parentheses (listed in order of decreasing polarity): MeOH (0.762), DMSO (0.444), acetone (0.355), chloroform (0.259), THF (0.207) and toluene (0.099). ... 3

Table A2. Natural transition orbitals (NTOs) for the five lowest transitions of 1. ... 3

Table A3. Natural transition orbitals (NTOs) for the five lowest transitions of 2. ... 4

Table A4. Natural transition orbitals (NTOs) for the five lowest transitions of 3. ... 4

Table A5. Natural transition orbitals (NTOs) for the five lowest transitions of 4. ... 5

Table A1. Photophysical properties of Nile Red (NR) and the five analogs 1–5.

Molar extinction coefficient ε [103 _M-1_cm-1_]

~1050-nm 2PA band ~860-nm 2PA band

Solute Solvent Solvent polarity

Absorption

max [nm] max [nm] Emission Stokes shift max [nm] Quantum yield Φ

Figure A1. Normalized absorption (green) and fluorescence (orange) spectra for Nile Red (NR) and the five analogs 1–5 at concentrations of 3.0 μM in the following six solvents

with relative polarities given in parentheses (listed in order of decreasing polarity): MeOH (0.762), DMSO (0.444), acetone (0.355), chloroform (0.259), THF (0.207) and toluene (0.099). 400 500 600 700 800 Wavelength [nm] P o la ri ty MeOH PhMe CHCl3 DMSO Acetone THF O N N O NR 400 500 600 700 800 Wavelength [nm] P o la ri ty MeOH PhMe CHCl3 DMSO Acetone THF 400 500 600 700 800 Wavelength [nm] P o la ri ty MeOH PhMe CHCl3 DMSO Acetone THF 400 500 600 700 800 Wavelength [nm] P o la ri ty MeOH PhMe CHCl3 DMSO Acetone THF O N N O 1 CF3 400 500 600 700 800 Wavelength [nm] P o la ri ty MeOH PhMe CHCl3 DMSO Acetone THF 400 500 600 700 800 Wavelength [nm] P o la ri ty MeOH PhMe CHCl3 DMSO Acetone THF

Table A2. Natural transition orbitals (NTOs) for the five lowest transitions of 1.

State Occupied NTO Virtual NTO Transition

S1 𝜋 → 𝜋∗

S2 𝑛 → 𝜋∗

S3 𝜋 → 𝜋∗

S4 𝜋 → 𝜋∗

Table A3. Natural transition orbitals (NTOs) for the five lowest transitions of 2.

State Occupied NTO Virtual NTO Transition

S1 𝜋 → 𝜋∗

S2 𝑛 → 𝜋∗

S3 𝜋 → 𝜋∗

S4 𝜋 → 𝜋∗

S5 𝑛 → 𝜋∗

Table A4. Natural transition orbitals (NTOs) for the five lowest transitions of 3.

State Occupied NTO Virtual NTO Transition

S1 𝜋 → 𝜋∗

S2 𝑛 → 𝜋∗

S3 𝜋 → 𝜋∗

S4 𝜋 → 𝜋∗

Table A5. Natural transition orbitals (NTOs) for the five lowest transitions of 4.

State Occupied NTO Virtual NTO Transition

S1 𝜋 → 𝜋∗

S2 𝑛 → 𝜋∗

S3 𝜋 → 𝜋∗

S4 𝜋 → 𝜋∗

S5 𝑛 → 𝜋∗

Table A6. Natural transition orbitals (NTOs) for the five lowest transitions of 5.

State Occupied NTO Virtual NTO Transition

S1 𝜋 → 𝜋∗

S2 𝑛 → 𝜋∗

S3 𝜋 → 𝜋∗

S4 𝜋 → 𝜋∗