Supplementary Data

Synthesis and Self-Assembly of Thiol-Modified Tellurophenes

Gabrielle C. Hoover, Jennifer Ham, Connie Tang, Elisa I. Carrera, and Dwight S. Seferos*

Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 Canada

E-mail: dseferos@chem.utoronto.ca

Table of Contents:

Synthetic procedures and characterizationS2

Mass spectrum of mixture of thioacetate (6) productsS5

1H, 13C, and 125Te NMR of synthesized compoundsS6

XPS spectraS18

Synthetic Procedures and Characterization

4-((trimethylsilyl)ethynyl)phenol (1):

4-iodophenol (5.3 g, 24.1 mmol), copper(I) iodide (138.4 mg, 0.73 mmol) and Pd(PPh3)2Cl2 (506 mg, 0.72 mmol) were put in a flame-dried 3-neck flask under nitrogen. Triethylamine (80 mL) was added to form an opaque orange-yellow solution. TMS-acetylene (6.0 mL, 42.5 mmol) was added, causing the solution to turn green with white precipitate. The mixture was heated at 80 ˚C for three hours resulting in the formation of a black precipitate. The black precipitate was filtered, and the product was purified by column chromatography (silica gel, 3:2 hexanes : ethyl acetate) 3:2 to give a brown oil (3.9 g, 85%): 1H NMR (400 mHz, CHCl3) 𝛿 7.38 (m, 2H), 6.75 (m, 2H), 0.23 (s, 9H).

1-ethynyl-4-(methoxy triethylene glycol)benzene (2):

1 (2.1 g, 11.2 mmol), tri(ethylene glycol) monomethyl ether tosylate (3.7 g, 11.6 mmol), K2CO3 (6.7 g, 48.4 mmol), and DMF (21 mL) were added to a 3 neck flame-dried flask under nitrogen. The mixture was heated at 85 ˚C for 20 hours. The resulting solution was diluted with water, and the product was extracted with diethyl ether. The organic layer was washed with water and brine, dried over sodium sulfate, and purified by column column chromatography (silica gel, 3:1 hexane : ethyl acetate) to give an orange oil (1.20 g, 41%): 1H NMR (400 mHz, CHCl3) 𝛿 7.41 (m, 2H), 6.85 (m, 2H), 4.14-3.53 (m, 12H), 3.37 (s, 3H), 2.99 (s, 1H).

1-bromoethynyl-4-(methoxy triethylene glycol)benzene (3):

2 (330 mg, 1.2 mmol), NBS (330 mg, 1.9 mmol), AgNO3 (263 mg, 1.5 mmol) and acetone (13.4 mL) were combined in a round bottom flask. The flask was covered with aluminum foil and stirred overnight. The solution was diluted with water (10 mL), then the organic components were extracted with diethyl ether, washed with water and brine, and dried over sodium sulfate to give an oily orange solid (396 mg, 96%): 1H NMR (400 mHz, CHCl3) 𝛿 8.02 (m, 2H), 6.96 (m, 2H), 4.21-3.54 (m, 12H), 3.37 (s, 3H).

6-(4-(2-methoxy triethylene glycol)phenyl)hexa-3,5-diyn-1-ol (4):

3 (389 mg, 1.13 mmol) was sparged in methanol (1.5 mL) and water (0.5 mL) for 30 minutes, as was a butylamine / water solution (2.4 mL, 30%). The butylamine solution was added to copper(I) chloride (spatula tip), forming a blue solution. A few small hydroxylamine hydrochloride crystals were added to form a clear solution. 1-Butynol (0.2 mL, 2.64 mmol) was added, causing the solution to turn opaque yellow. The solution was cooled in an ice bath, then 3 was added slowly over 5 minutes, forming a dark red solution. The mixture stirred for 22 hours at room temperature then was extracted with ethyl acetate, washed with 1 M HCl and brine, dried over sodium sulfate, and purified by column chromatography (silica gel, 2:1 DCM : ethyl acetate) to give a yellow oil (87.5 mg, 23%): 1H NMR (400 mHz, CHCl3) 𝛿 7.39 (m, 2H), 6.82 (m, 2H), 4.12-3.52 (m, 12H), 3.76 (t, J = 6.3 Hz, 2H), 3.37 (s, 3H), 2.61 (t, J = 12.6 Hz, 2H). TOF- MS (DART +) m/z 333.2 [M + H]+.

2-(5-(4-(2-methoxy triethylene glycol)phenyl)tellurophen-2-yl)ethan-1-ol (5):

Tellurium powder (120 mg, 0.94 mmol) and sodium borohydride (140 mg, 3.7 mmol) were added to a 3 neck flask with a water / ethanol solution (15 mL, 3% v/v) under nitrogen. The mixture was heated at 112 ˚C for 2.5 hours, changing from purple to pink. A solution of 4 (85 mg, 0.26 mmol) in ethanol (15 mL) was sparged for one hour, the reaction temperature was reduced to 80 ˚C, the diyne solution was added, and the combined solution was stirred at 80 ˚C for an additional 18 hours. The resulting mixture was filtered through celite, and the plug was washed with ethanol until the filtrate was clear, giving a tan solid (71.2 mg, 60%): 1H NMR (400 mHz, CHCl3) 𝛿 7.51 (d, J = 4.1 Hz, 1H), 7.38 (d, J = 4.1 Hz, 1H), 7.36 (m, 2H), 6.87 (m, 2H), 4.15-3.53 (m, 14H), 3.37 (s, 3H), 3.11 (t, J = 5.4 Hz, 2H). TOF- MS (DART +) m/z 465.1 [M + H]+.

2-(5-(4-(2-methoxy triethylene glycol)phenyl)tellurophen-2-yl)ethyl ethanethioate (6):

A solution of triphenyl phosphine (175 mg, 0.64 mmol) in THF (1.5 mL) was cooled to 0 ˚C under inert atmosphere. DIAD (0.2 mL, 1.01 mmol) was added and allowed to stir for 30 minutes, turning the solution from clear to orange in color. A solution of 5 (101 mg, 0.22 mmol) in 1.5 mL THF was added, followed by thioacetic acid (0.1 mL, 1.4 mmol). The solution was stirred for 22 hours then THF was removed. Some impurities were removed by column chromatography (silica gel, 2:1 DCM : ethyl acetate), but the pure yield could not be determined: 1H NMR (400 mHz, CHCl3) 𝛿 7.47 (d, J = 4.1 Hz, 2H), 7.34 (m, 3H), 6.86 (m, 2H), 4.15-3.54 (m, 12H), 3.37 (s, 3H), 3.13 (t, J = 3.5 Hz, 2H), 2.55 (s, 2H), 2.36 (s, 3H). TOF- MS (DART +) m/z 523.1 [M + H]+.

2-(5-(4-(2-methoxy ethylene glycol)phenyl)tellurophen-2-yl)ethane-1-thiol (7):

The impure mixture of 6 (84 mg) was mixed with potassium carbonate (5.5 mg, 0.04 mmol) in methanol (4.5 mL) for 15 minutes. The reaction was monitored by TLC (silica TLC plate, ethyl acetate eluent). The solution was washed with brine, and the product was extracted with chloroform. When dried and resuspended in methanol, the impurity resulting from the synthesis of 6 dissolved and was decanted from the insoluble target thiol to give a yellow solid (6-7 combined: 13.4 mg, 13%): 1H NMR (400 mHz, CHCl3) 𝛿 7.49 (d, J = 4.1 Hz, 1H), 7.39 (m, 1H), 7.35 (m, 2H), 6.87 (m, 2H), 4.15-3.54 (m, 12H), 3.37 (s, 3H), 3.28 (t, J = 6.9 Hz, 2H), 2.99 (t, J = 6.8 Hz, 2H). TOF- MS (DART +) m/z 479.1 [M + H]+.

((4-(3-bromopropoxy)phenyl)ethynyl)trimethylsilane (8):

4-iodophenol (1.0 g, 4.545 mmol), 1,3-dibromopropane (3.67 g, 18.18 mmol), K2CO3 (3.141 g, 22.73 mmol), and dry acetone (5 mL) were added to a flame-dried 3-neck flask and heated at 65 ˚C overnight. The crude mixture was filtered, diluted with water, extracted with dichloromethane, and purified with a silica column in hexanes to give a yellow oil (0.456 g, 29%): 1H NMR (400 mHz, CHCl3) 𝛿 7.46 (m, 2 H), 6.86 (m, 2H), 4.14 (t, J = 7.7 Hz, 2H), 3.60 (t, J = 4.8 Hz, 2H), 2.37 (m, 2H), 0.08 (s, 9H).

S-(prop-2-yn-1-yl) ethanethioate (11):

A solution 3-bromopropyne (0.84 mL, 7.58 mmol, 1.0 eq.) in DMF (10 mL) was cooled to 0 °C. Potassium thioacetate (0.97 g, 8.40 mmol, 1.1 eq.) was added dropwise under argon over 30 minutes then allowed to stir for 21 hours at room temperature. The solution was added to 1 M HCl, extracted with diethyl ether, washed with water, and dried over sodium sulfate to produce an orange oil (1.03 g, 75%): 1H NMR (400 mHz, CHCl3) 𝛿 3.63 (s, 2H) 2.35 (s, 3H), 2.17 (s, 1H).

Mass spectrum of mixture of thioacetate (6) products

Figure S1. Mass spectrum of crude mixture of 6, a thioacetate-modified tellurophene, and its co-eluent.

Figure S2. 1H NMR spectrum of 4-((trimethylsilyl)ethynyl)phenol (1).

Figure S3. 1H NMR spectrum of 1-ethynyl-4-(methoxy triethylene glycol)benzene (2).

Figure S4. 1H NMR spectrum of 1-bromoethynyl-4-(methoxy triethylene glycol)benzene (3).

Figure S5. 1H NMR spectrum of 6-(4-(2-methoxy triethylene glycol)phenyl)hexa-3,5-diyn-1-ol (4).

Figure S6. 1H NMR spectrum of 2-(5-(4-(2-methoxy triethylene glycol)phenyl)tellurophen-2-yl)ethan-1-ol (5).

Figure S7. 13C NMR spectrum of 2-(5-(4-(2-methoxy triethylene glycol)phenyl)tellurophen-2-yl)ethan-1-ol (5).

Figure S8. 125Te NMR of 2-(5-(4-(2-methoxy triethylene glycol)phenyl)tellurophen-2-yl)ethan-1-ol (5).

Figure S9. 1H NMR spectrum of 2-(5-(4-(2-methoxy triethylene glycol)phenyl)tellurophen-2-yl)ethyl ethanethioate (6).

Figure S10. 13C NMR spectrum of 2-(5-(4-(2-methoxy triethylene glycol)phenyl)tellurophen-2-yl)ethyl ethanethioate (6).

Figure S11. 1H NMR spectrum of 2-(5-(4-(2-methoxy ethylene glycol)phenyl)tellurophen-2-yl)ethane-1-thiol (7).

Figure S12. 13C NMR spectrum of 2-(5-(4-(2-methoxy ethylene glycol)phenyl)tellurophen-2-yl)ethane-1-thiol (7).

Figure S13. 125Te NMR spectrum of 2-(5-(4-(2-methoxy ethylene glycol)phenyl)tellurophen-2-yl)ethane-1-thiol (7).

XPS Spectra

Figure S14. XPS survey of ligand monolayer on a gold-coated silicon substrate.

Figure S15. Elemental composition of ligand monolayer on a gold-coated silicon substrate.

Figure S16. XPS survey of a gold-coated silicon substrate as a control.

Figure S17. Elemental composition of a gold-coated silicon substrate as a control.

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