Electronic Supplementary Information for: Gram-scale Synthesis of a Bench-Stable 5,5 -Unsubstituted Terpyrrole

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1 Electronic Supplementary Information for: Gram-scale Synthesis of a Bench-Stable 5,5 -Unsubstituted Terpyrrole James T. Brewster II, a Hadiqa Zafar, a Matthew McVeigh, a Christopher D. Wight, a Gonzalo Anguera, a Axel Steinbrück, a Vincent M. Lynch, a and Jonathan L. Sessler*,a,b a Department of Chemistry, The University of Texas at Austin, Texas , USA b Institute for Supramolecular and Catalytic Chemistry, Shanghai University, Shanghai , China sessler@cm.utexas.edu Contents 1 H & 13 C NMR spectral data S2-3 1 H NMR stability studies and data S3-4 X-ray crystallographic data S5-8 Notes References S9 S9 S1

2 Materials & General Methods All reagents and solvents were purchased from commercial supplies and used without further purification. Analytical thin-layer chromatography (TLC) was performed using commercial precoated silica gel plates containing a fluorescent indicator. Column chromatography was carried out using silica gel ( mm). High-resolution mass spectra (HRMS) were measured using an Ion Spec Fourier Transform mass spectrometer (9.4 T). Proton and carbon NMR spectra were recorded using a Varian 400 spectrometer or Bruker Avance III 500 MHz instrument at room temperature and chemical shifts are reported in ppm using TMS or solvent residual signals as internal reference standards. Data for 1 H NMR spectra are reported as follows: chemical shift (δ ppm), multiplicity, coupling constant (Hz), and integration. Data for 13 C NMR spectra are reported in terms of chemical shift. All NMR spectroscopic solvents were purchased from Cambridge Isotope Laboratories. UV-Vis spectra were recorded from 250 to 800 nm using a Varian Cary 5000 spectrophotometer at room temperature. Fluorescence spectra were recorded on a Photon Technology International Fluorescence Master fluorimeter. The source was a 75 W Xenon short arc lamp. A cell length of 10 mm and spectroscopic grade acetonitrile was used for all UV-Vis and fluorescence studies. 1 H & 13 C NMR spectral data S2

3 1 H NMR stability studies and data The solution stability study (9.5 mg of 1 in 1 ml of CDCl 3 ) was monitored by 1 H NMR spectroscopy at t = 1, 24, and 48 hours then purified by silica gel chromatography at 72 hours to yield 4.5 mg (47%) of terpyrrole 1. Interestingly, no changes in the 1 H NMR spectral features were observed by means of 1 H NMR spectral analysis despite formation of a black precipitate. (a) (b) Figure S1. Pictures of the samples used for the solution state 1 H NMR spectral stability study at (a) t = 1 h and (b) t = 48 h. S3

4 48 h 24 h 1 h Figure S2. 1 H NMR spectra associated with the solution state stability studies as recorded at t = 1, 24, and 48 h. The solid-state stability (10.3 mg of 1 in 1 ml CDCl 3 ) was monitored by 1 H NMR spectroscopy by recording spectra at t = 1 week using 1,2-dichloroethane (2 equivalents; 8H) as an internal reference. Figure S3. 1 H NMR spectrum of terpyrrole 1 recorded after 1 week of exposure to normal laboratory conditions. 1,2-dichloroethane (2 equivalents) was used as an internal reference. S4

5 X-ray Crystallography Data X-ray experimental for compound 1: Crystals grew as clear, colorless needles by slow evaporation from dichloromethane: hexanes (1:1, v/v). The data crystal was cut from a larger crystal and had approximate dimensions; 0.28 x 0.15 x 0.11 mm. The data were collected at -173 C on a Nonius Kappa CCD diffractometer using a Bruker AXS Apex II detector and a graphite monochromator with MoKα radiation (λ = Å). Reduced temperatures were maintained by use of an Oxford Cryosystems 700 low-temperature device. A total of 968 frames of data were collected using ω-scans with a scan range of 0.6 and a counting time of 69 seconds per frame. Details of crystal data, data collection and structure refinement are listed in Table S1. Data reduction were performed using SAINT V8.27B. 1 The structure was solved by direct methods using SHELXT 2 and refined by full-matrix least-squares on F2 with anisotropic displacement parameters for the non-h atoms using SHELXL-2016/6. 3 Structure analysis was aided by use of the programs PLATON 4 and WinGX. 5 The hydrogen atoms bound to carbon atoms were calculated in idealized positions. The hydrogen atoms on the nitrogen atoms were observed in a F map and refined with isotropic displacement parameters. The function, Σω( Fo 2 - Fc 2)2, was minimized, where ω = 1/[(Σ(Fo))2 + (0.0368*P) 2 + (0.2712*P)] and P = ( Fo Fc 2 )/3. Rω(F 2 ) refined to , with R(F) equal to and a goodness of fit, Σ, = Definitions used for calculating R(F),Rω(F 2 ) and the goodness of fit, Σ, are given below. 6 The data were checked for secondary extinction, but no correction was necessary. Neutral atom scattering factors and values used to calculate the linear absorption coefficient are from the International Tables for X-ray Crystallography (1992). 7 All figures were generated using SHELXTL/PC. 8 Tables of positional and thermal parameters, bond lengths and angles, torsion angles and figures are found in the cif files. These files are available from the Cambridge Crystallographic Data Centre by making reference to CCDC number S5

6 Table S1. Crystal data and structure refinement for 1. Empirical formula Formula weight Temperature Wavelength Crystal system C18 H19 N3 O4 100(2) K Å orthorhombic Space group P Unit cell dimensions a = (7) Å α = 90. Volume Z 4 Density (calculated) mg/m 3 Absorption coefficient mm -1 b = (9) Å β = 90. c = (2) Å γ = (3) Å3 F(000) 720 Crystal size x x mm 3 Theta range for data collection to Index ranges Reflections collected <=h<=9, -12<=k<=12, -29<=l<=28 Independent reflections 4004 [R(int) = ] Completeness to theta = % Absorption correction Semi-empirical from equivalents Max. and min. transmission 1.00 and Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 4004 / 0 / 240 Goodness-of-fit on F Final R indices [I>2sigma(I)] R1 = , wr2 = R indices (all data) R1 = , wr2 = Absolute structure parameter 0.1(5) Extinction coefficient Largest diff. peak and hole n/a and e.å-3 S6

7 Figure S4. View of 1 showing the atom-labeling scheme. Displacement ellipsoids are scaled to the 50% probability level. Figure S5. View of 1 showing intramolecular hydrogen bonding. Displacement ellipsoids are scaled to the 50% probability level. S7

8 Figure S6. View of 1 showing intermolecular hydrogen bonding. Displacement ellipsoids are scaled to the 50% probability level. S8

9 Notes [1] Pd(PPh 3 ) 2 Cl 2 purchased from Strem Chemicals Inc. consistently gave higher yields and no leached triphenylphosphine was observed in column purification. [2] Failure to properly purge solids and solvent with N 2 or not maintaining an N 2 atmosphere throughout the course of the reaction resulted in greatly diminished yields. In these instances, final product was obtained in 61-81% yield. [3] If too much CH 2 Cl 2 is added then, after addition of hexanes, some solvent can be blown off under a stream of nitrogen to facilitate precipitation. References [1] SAINT V8.27B Bruker AXS Inc, 2012, Madison, WI. [2] Sheldrick, G. M. SHELXT Integrated space-group and crystal-structure determination. Acta Cryst. 2015, A71, 3-8. [3] Sheldrick, G. M. Crystal structure refinement with SHELXL. Acta Cryst. 2015, C71, 3-8. [4] Spek, A. L. Structure validation in chemical crystallography. Acta Cryst. 2009, D65, [5] Farrugia, J. L. WinGX suite for small-molecule single-crystal crystallography. J. Appl. Cryst. 1999, 32, [6] Rω(F 2 ) = {Σω( Fo 2 - Fc 2 ) 2 /Σω( Fo ) 4 } 1/2 where w is the weight given each reflection. R(F) = Σ( Fo - Fc )/Σ Fo } for reflections with Fo > 4(σ(Fo)). Σ = [Σω( Fo 2 - Fc 2 ) 2 /(n - p)] 1/2, where n is the number of reflections and p is the number of refined parameters. [7] Wilson, A. J. C. International Tables for X-ray Crystallography, Boston: Kluwer Academic Press, 1992, Vol. C., Tables and [8] Sheldrick, G. M. SHELXTL/PC, Siemens Analytical X-ray Instruments, Inc., Madison, Wisconsin, USA, 1994, Version S9