Department of Chemistry, University of Basel, St. Johanns-Ring 19, Spitalstrasse 51, and Klingelbergstrasse 80, CH-4056 Basel, Switzerland

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1 Charge Transfer Pathways in Three Isomers of Naphthalene-Bridged Organic Mixed Valence Compounds Hauke C. Schmidt, Mariana Spulber, Markus Neuburger, Cornelia G. Palivan, Markus Meuwly,* and Oliver S. Wenger* Department of Chemistry, University of Basel, St. Johanns-Ring 19, Spitalstrasse 51, and Klingelbergstrasse 80, CH-4056 Basel, Switzerland Table of Contents Complete analytical data for all compounds from Scheme 1 Route of synthesis for the target molecules More detailed illustrations of the resonance structures from Scheme 2 Electrochemistry Gaussian fits of the IVCT bands with resulting parameters Computational Data Crystallographic information S2 S22 S23 S24 S26 S27 S37 S1

2 Figure S1. 1 H NMR spectrum of compound (N-1,8) in CDCl 3. S2

3 Figure S2. 13 C NMR spectrum of compound (N-1,8) in CD 2 Cl 2. S3

4 Figure S3. ESI-HRMS measurement of compound (N-1,8). S4

5 Figure S4. Elemental analysis report for compound (N-1,8). S5

6 Figure S5. 1 H NMR spectrum of compound (N-1,5) in CD 2 Cl 2. S6

7 Figure S6. 13 C NMR spectrum of compound (N-1,5) in CD 2 Cl 2. S7

8 Figure S7. ESI-HRMS measurement of compound (N-1,5). S8

9 Figure S8. Elemental analysis of compound (N-1,5). S9

10 Figure S9. 1 H NMR spectrum of compound (N-2,6) in DMSO-d 6. S10

11 Figure S C NMR spectrum of compound (N-2,6) in DMSO-d 6. S11

12 Figure S11. ESI-HRMS measurement of compound (N-2,6). S12

13 Figure S12. Elemental analysis of compound (N-2,6). S13

14 Figure S13. 1 H NMR spectrum of compound (N-1) in acetone-d 6. S14

15 Figure S C NMR spectrum of compound (N-1) in acetone-d 6. S15

16 Figure S15. ESI-HRMS measurement of compound (N-1). S16

17 Figure S16. Elemental analysis of compound (N-1). S17

18 Figure S17. 1 H NMR spectrum of compound (N-2) in acetone-d 6. S18

19 Figure S C NMR spectrum of compound (N-2) in acetone-d 6. S19

20 Figure S19. ESI-HRMS measurement of compound (N-2). S20

21 Figure S20. Elemental analysis of compound (N-2). S21

22 Route of synthesis for the target molecules Scheme S1. Synthesis of the 5 molecules from Scheme 1 with following reagents and conditions: a).pd(dba) 2, [HP( t Bu) 3 ]BF 4, NaO t Bu, toluene, 85 C, overnight; b) I 2, bis(trifluoroacetoxy)iodobenzene, CH 2 Cl 2, 1 h r.t., 2 h reflux; c) n-buli, 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2- dioxaborolane, THF, -78 C, 2 h, r.t. overnight; d) NaNO 2, KI, H 2 SO 4 (6.9 M), -20 C, 80 C, 5 min; e) NaNO 2, KI, H 2 SO 4 (6.9 M), H 3 COOH, 0 C, r.t., 4 h; f) Pd(PPh 3 ) 4, Na 2 CO 3, THF/H 2 O, reflux, overnight. S22

23 More detailed illustrations of the resonance structures from Scheme 2 Scheme S2. More detailed illustrations of the mixed valence resonance forms from Scheme 2, including details regarding the R-substituents. S23

24 Simulated voltammograms and corresponding parameters for di-substituted naphthalenes Table S1. Simulation parameters for cyclic voltammograms. E1 [V] E2 [V] k 0 [cm/s] a f b ca initial [mol/l] c DA [cm 2 /s] d scan rate [V/s] (N-1,8) (N-1,5) (N-2,6) a This is the standard electrochemical rate constant. b This is the transfer coefficient. c Species A is the neutral form; the initial concentrations of species B (monocation) and C (dication) were 0 mol/l in all cases. d The diffusion coefficient was always assumed to be identical for species A, B, and C. The electrode radius was 0.15 cm. Figure S21. Solid black lines: experimental cyclic voltammograms reproduced from Figure 1. Dotted red lines: simulated voltammograms using the EC-Lab software V10.34 from Bio-Logic - Science Instruments and the parameters listed in Table S1. S24

25 Figure S22. Cyclic voltammograms obtained in dry and de-oxygenated CH 2 Cl 2 with 0.1 M TBABArF 24 at 22 C. The potential sweep rate was 100 mv/s. The waves at V vs. Fc + /Fc are due to decamethylferrocene which was added in small quantities for internal potential calibration. S25

26 Gaussian fits of the IVCT bands with resulting parameters Table S2. Parameters obtained from Gaussian fits to the IVCT bands. a cmpd max [cm -1 ] FWHM [cm -1 ] area [M -1 cm -2 ] (N-1,8) (N-1,5) (N-2,6) a Extracted from Figure S23. max and FWHM are associated with errors of 25 cm -1. Figure S23. Solid black traces: experimental absorption spectra in CH2Cl2 at 22 C. Dotted blue traces: Gaussian fits to the experimental spectra. Dashed red traces: sums of the individual Gaussians. Parameters of the Gaussian functions used to fit the IVCT bands are reported in Table S2. S26

27 Computational Data Geometry optimization was performed at the B3LYP/6-31+G** level for the monocationic compounds (N-1,8) +, (N-1,5) + and (N-2,6) +. The cartesian coordinates are given in Å. In order to validate the use of B3LYP/6-31+G**, the UV-Vis spectra (Figure S23) and the spin density distribution (Table S3) for (N-1,8) + were also determined from calculations with BMK/ G** [1]. As noted earlier, [1] the BMK hybrid functional is suitable for organic mixed-valence compounds and expected to perform similarly as the BLYP35 hybrid functional. With B3LYP/6-31+G** the experimental UV-Vis spectrum can be described quite well (Figure 23b), specifically for the bands at 370 and 740 nm. However, the shoulder at 860 nm is shifted to 1300 nm and not reproduced reliably at this level. Conversely, BMK/ G** improves the situation as far as the near-infrared band is concerned (Figure 23c). There is a slight blue shift for the high-frequency bands, although the splitting between the two again agrees with the experimental observations. We conclude that both methods are equally well suited for simulation of our experimental UV-Vis spectra. With regard to the calculated spin densities we note that B3LYP/6-31+G** leads to slightly stronger delocalization than BMK/ G**. This manifests itself in somewhat lower spin densities on the triarylamine-n (0.30 vs. 0.39, Table S3) and the triarylamine C in -position to naphthalene (0.17 vs. 0.21, Table S3). However, the key point for our study is the spin density on the naphthalene bridge, and we note that the spin density on this site is independent of the computational approach employed (0.02, Table S3). S27

28 Figure S24. Optical absorption spectra for (N-1,8) + : a) experimental spectrum (measured in CH2Cl2), b) simulated at B3LYP/6-31+G** level, c) simulated at BMK/ G** level. S28

29 Table S3. DFT-calculated spin densities for different portions of the radical cations (N-1,8) + at different levels. (N-1,8) + B3LYP/6-31+G** BMK/ G** triarylamine triarylamine N atoms triarylamine C atoms in α- position to naphthalene naphthalene bridging unit S29

30 Table S3. Cartesian coordinates and absolute energy value for the optimized geometry of (N-1,8) +. Total energy: hartree Symbol X Y Z C C C C C C N C C C C C C O C O C C C C C C C C C C C C C C C C C C C C C C C S30

31 N C C C C C C O C C C C C C C O C H H H H H H H H H H H H H H H H H H H H H H H H H H H H H S31

32 H H H H H H H H H H H H H Table S4. Cartesian coordinates and absolute energy value for the optimized geometry of (N-1,5) +. Total energy: hartree Symbol X Y Z C C C C C C N C C C C C C O C O C C C C C C S32

33 C C C C C C C C C C C C C C C C C N C C C C C C O C C C C C C C O C H H H H H H H H H H H H S33

34 H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H Table S5. Cartesian coordinates and absolute energy value for the optimized geometry of (N-2,6) +. Total energy: hartree Symbol X Y Z C C C C C C N S34

35 C C C C C C O C O C C C C C C C C C C C C C C C C C C C C C C C N C C C C C C O C C C C C C S35

36 C O C H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H S36

37 Crystallographic information Figure S25. X-ray crystallographic structure of compound (N-1,8) with thermal ellipsoids drawn at the 50% probability level. S37

38 Crystal data for hsch1: formula C 50 H 42 N 2 O 4, M = , F(000) = 3104, colorless block, size mm 3, orthorhombic, space group F d d 2, Z = 8, a = (4) Å, b = (11) Å, c = (4) Å, α = 90, β = 90, γ = 90, V = (4) Å 3, D calc. = Mg m -3. The crystal was measured on a Bruker Kappa Apex2 diffractometer at 123K using graphite-monochromated Cu K α - radiation with λ = Å, Θ max = Minimal/maximal transmission 0.93/0.97, μ = mm -1. The Apex2 suite [2] has been used for data collection and integration. From a total of reflections, 3415 were independent (merging r = 0.028). From these, 3395 were considered as observed (I>2.0σ(I)) and were used to refine 255 parameters. The structure was solved by the charge flipping method using the program Superflip [3]. Least-squares refinement against F was carried out on all non-hydrogen atoms using the program CRYSTALS [4]. R = (observed data), wr = (all data), GOF = Minimal/maximal residual electron density = -0.12/0.12 e Å -3. Chebychev polynomial weights [5] were used to complete the refinement. Plots were produced using Mercury [6]. Crystallographic data (excluding structure factors) for the structure in this paper have been deposited with the Cambridge Crystallographic Data Center, the deposition number is Copies of the data can be obtained, free of charge, on application to the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK [fax: or deposit@ccdc.cam.ac.uk]. [1] Parthey, M.; Kaupp, M.; Chem. Soc. Rev. 2014, 43, [2] Bruker Analytical X-ray Systems, Inc., Apex2, Version 2 User Manual, M86-E01078, Madison, WI. [3] Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, [4] Betteridge, P.W., Carruthers, J.R., Cooper, R.I., Prout, K. & Watkin, D.J. (2003). J. Appl. Cryst. 36, [5] Watkin D.J. (1994). Acta Cryst, A50, [6] C. F. Macrae, I. J. Bruno, J. A. Chisholm, P. R. Edgington, P. McCabe, E. Pidcock, L. Rodriguez- Monge, R. Taylor, J. van de Streek and P. A. Wood, J. Appl. Cryst., 41, , S38