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Electronic Supplementary Information for:

On-Surface Cross Coupling Methods for the Construction of Modified

Electrode Assemblies with Tailored Morphologies

Amber A. S. Gietter, Rachel C. Pupillo, Glenn P. A. Yap, Thomas P. Beebe, Jr., Joel Rosenthal,* and Donald A. Watson*

Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716

Index Page General Experimental Methods S2–S3 Synthetic Protocols S4–S7 Fig. S-1 Iron Region HR-XPS Spectra for CP3 – CP5 S9 Fig. S-2 Nitrogen Region HR-XPS Spectra of Ferrocenyl Azide (4) and CP5 S10 Fig. S-3 Electrochemical Stripping of Copper from CP5 S11 Fig. S-4 Fully Labeled Thermal Elipsoid Plots for Fc1 – Fc3 S12 Table S-1 Crystal Data and Structure Refinement Parameters for Fc1 – Fc3 S13 References S14 NMR Spectra for New Compounds S15-S33

Electronic Supplementary Material (ESI) for Chemical ScienceThis journal is © The Royal Society of Chemistry 2013

General Experimental Methods General Materials and Methods: Reactions were performed in oven-dried round-bottomed flasks unless otherwise noted. Reactions that required an inert atmosphere were conducted under a positive pressure of N2 using flasks fitted with Suba-Seal rubber septa or in a nitrogen filled glove box. Solvents for synthesis were of reagent grade or better and were dried by passage through activated alumina and then stored over 4 Å molecular sieves prior to use.1 Surface deposition and surface cross-coupling reactions (except for Glaser coupling) were carried out in a nitrogen-filled glovebox. All glassware was oven dried for a minimum of two hours or flame dried under vacuum prior to use. Reagents including 4-((triisopropylsilyl)ethynyl)aniline,2 4-((triisopropylsilyl)ethynyl)benzenediazonium tetrafluoroborate (1),3 and 4-iodophenylferrocene (2)4 were synthesized as reported in the literature. Electrochemical grade tetrabutylammoniumhexafluorophosphate (TBAPF6) was purchased and used as received. All other substances and reagents were obtained from commercial sources and used as received. Carbon paper was purchased from Fuel Cell Earth LLC and stored under air. Before modification, the paper was cut into 15mm x 25mm rectangles and transferred into a nitrogen-filled glovebox, unless otherwise noted. “Double manifold” refers to a standard Schlenk-line gas manifold equipped with nitrogen and vacuum (ca. 100 mtorr).

Instrumentation and Chromatography. 400 MHz 1H and 101 MHz 13C spectra were recorded using a 400 MHz FT-NMR spectrometer equipped with a Bruker CryoPlatform. 13C spectra were recorded using Attached Proton Test phase pulse sequence; carbons with an odd number of protons are phased down and those with an even number of protons are phased up.5 All samples were analyzed in the indicated deutro-solvent and were recorded at ambient temperatures. Chemical shifts are reported in ppm. Proton spectra are referenced to the residual proton resonance of the deuterated solvent (CHCl3 = δ 7.26) and carbon spectra are referenced to the carbon resonances of the solvent (CDCl3 = δ 77.16). All chemical shifts are reported using the standard δ notation in parts-per-million. IR spectra were recorded on an Nicolet Magma-IR 560 FT-IR spectrometer in KBr pellets. Column chromatography was preformed with 40-63 µm silica gel with the eluent reported in parentheses. Analytical thin-layer chromatography (TLC) was performed on precoated glass plates and visualized by UV or by staining with KMnO4. GC/MS data was collected using an Agilent 6850 series GC and 5973 MS detector. Low resolution atmospheric-pressure chemical ionization (APCI) data was collected using a Shimadzu LC/MS-2020 single quadrupole MS coupled with an HPLC system, with dual ESI/APCI source via direct injection with a flow rate of 0.4 mL/min and a solvent system of 90% acetonitrile: 10% water (with 0.1% formic acid). High-resolution mass spectrometry analyses were performed by the Mass Spectrometry Laboratory at the University of Illinois at Urbana-Champaign.

Electrochemical Measurements: All electrochemistry was performed using either a CHI-620D potentiostat/galvanostat, a CHI-760D bipotentiostat, or a BAS CV-50 potentiostat. Cyclic voltammetry was performed in a N2 or Ar filled glove box using a standard three-electrode configuration. Cyclic voltammograms for Fc1 – Fc3 were recorded for quiescent solutions using a glassy carbon working disk electrode (3.0 mm diameter), a platinum wire auxiliary electrode and a Ag/AgNO3 reference electrode. Unless otherwise noted, CV scans were recorded for quiescent solutions using a modified carbon paper, a platinum gauge auxiliary electrode and a Ag/AgNO3 reference electrode. All CV experiments were performed using dry acetonitrile containing 0.1 M TBAPF6 as the supporting electrolyte.

CV analysis of modified carbon substrates were initially carried out using a scan rate of 50 mV/s with a sensitivity of 100 µA/V. Laviron plots were constructed by measuring the variation in anodic (Ea) and cathodic (Ec) peak potential as a function of scan rate. Scan rates were varied as follows: 8, 10, 15, 20, 30, 50, 80, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, and 4000 mV/s. Laviron’s formalism was applied by plotting Ec – E1/2 and Ea – E1/2, where E1/2 = (Ea + Ec)/2, as a function of log of scan rate.6 The electron transfer

S2


rate constant (ETRC) was determined for CP3 – CP5 by fitting these data when Ea – Ec ≥ 200 mV.

The active surface area of the carbon paper substrates was assessed by chronocoulometry conducted using a 1.0 mM solution of ferricyanide (D = 6.3 × 10–6) in Millipore water containing 0.1 M KCl.7 The extent of diazonium grafting was calculated using standard coulometric methods.

X-Ray Photoelectron Spectroscopy (XPS). All XPS spectra were acquired using a VG ESCALAB 220I-XL spectrometer. The X-Rays used were monochromatic Al Kα X-Rays (1486.7eV) with a power of 105W (15 kv, 7 mA). The operating pressure in the main chamber was less than 1 × 10-8 torr. The X-Ray spot size was elliptical in shape with a semi-major axis of roughly 400µm.

Initial XPS survey scans were collected at a pass energy of 80 eV using a step size of 0.25 eV. All atomic percentages (𝜒!) were calculated from the surveys and were determined using

the equation: 𝜒! =!!

!!!!

!!! where Ai is the area calculated with a Shirley-type baseline, and Si is

the relative sensitivity factor. Atomic percentages do not include hydrogen in XPS. The atomic percentages reported are the compiled averages taken from a minimum of five separate spots per each individual carbon substrate sampled, and typically 8 to 10 individual carbon substrates. High-resolution XPS spectra were collected at a pass energy of 20 eV using a step size of 0.1 eV. Reported values for average atomic surface composition are the compiled averages of at least five surface spots from at least eight individual samples (n ≥ 40).

Genaration of Alkynyl Modified Carbon Paper Substrates CP1 and CP2. Electrochemical grafting and deprotection of diazonium 1 on bare carbon paper substrates was carried out by modifying a previously published procedure.3 Within a nitrogen filled glove box, a piece of carbon paper (~1 × 2 cm) working electrode was clipped to a platinum wire and immersed in 10 mL of a 0.1 M solution of TBAPF6 in acetonitrile containing 18.6 mg (50 µmol) of diazonium 1. A platinum gauze auxiliary and silver wire pseudo reference electrode were also placed within the vial. The electrodeposition was carried out by varying the applied potential between 0.5 and –0.3 V with a scan rate of 50 mV/s. The electrochemical grafting to generate CP1 was generally complete after roughly 5 – 7 cycles between these potentials. Following the electrochemical grafting, CP1 was rinsed with 8 mL of dry acetonitrile and then soaked in 4 mL of dry acetonitrile for 10 min. This cleaning process was repeated two additional times and the CP1 substrate was then allowed to dry under N2.

The TIPS protecting groups of CP1 were removed by immersing the modified carbon substrate in 10 mL of acetonitrile within N2 filled glove box. To the suspended CP1 substrate was added TBAF (13.0 mg, 50 µmol), and the resulting solution was allowed to stand at room temperature for 2 hr. Following removal of the modified carbon paper with forceps, the alkyne terminated carbon paper (CP2) was rinsed with 8 mL of dry acetonitrile and then soaked in 4 mL of dry acetonitrile for 10 min. This cleaning process was repeated two additional times and the CP2 substrate was then allowed to dry under N2. Tabulated XPS data demonstrating average atomic surface composition are reproduced below.

Element Average Atomic Percent (%)

CP1 CP2 C 1s 92.0 ± 0.8 96.2 ± 0.9 Si 2p 2.9 ± 0.3 0.4 ± 0.2 O 1s 2.5 ± 0.4 2.1 ± 0.5 N 1s 1.8 ± 0.3 1.0 ± 0.3 F 1s 0.7 ± 0.2 0.3 ± 0.2

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Synthetic Protocols

(S1) A hot 50 mL Schlenk flask equipped with a magnetic stir bar and a rubber septum was attached to a double manifold and cooled under vacuum. The flask was backfilled with nitrogen, the septum was removed, and iodophenylferrocene (1.00 g, 2.58

mmol), copper (I) iodide (6.4 mg, 33.6 µmol), and bis(triphenylphosphine) palladium(II) dichloride (18.2 mg, 25.8 µmol) were added. The septum was replaced, the flask was reattached to the double manifold, and evacuated and backfilled with nitrogen three times. Dry, degassed triethylamine (26 mL) and ethynyltrimethylsilane (1.10 mL, 7.73 mmol) were sequentially added using standard syringe technique. The reaction was heated to 55°C in an oil bath for 12 h. After the allotted time, the reaction was cooled to rt and opened to air. The reaction was diluted with dichloromethane (25 mL), transferred to a separatory funnel and washed twice with water (50 mL). The organic layer was dried with magnesium sulfate, filtered, and concentrated in vacuo. The crude reaction mixture was purified by column chromatography (10% CH2Cl2 in hexanes) to afford S1 (94%, 867 mg) as an orange solid: 1H NMR (400 MHz, CDCl3) δ 7.39 (apparent s, 4H), 4.65 (t, J = 1.8 Hz, 2H), 4.34 (t, J = 1.8 Hz, 2H), 4.01 (s, 5H), 0.26 (s, 9H); 13C NMR (101 MHz, CDCl3) δ 140.2, 132.1, 125.8, 120.3, 105.6, 94.2, 84.2, 69.9, 69.5, 66.6, 0.2; FTIR (cm-1): 3085, 2958, 2678, 2153, 1524, 1250, 868, 843; GC/MS (CI) 358.2 (M)+, 343.2 (M-Me)+; HRMS (EI+) m/z, calculated for [C21H22FeSi]+: 358.0840; found: 358.0832.

(3) To a 200 mL round bottom flask equipped with a magnetic stir bar was added TMS alkyne S1 (867 mg, 2.42 mmol), dichloromethane (7.8 mL), methanol (89 mL), and [1M] KOH (30 mL). The reaction was sealed with a polyethylene cap and stirred at rt for

18 h. Upon completion, the cap was removed, and the reaction was diluted with dichloromethane (30 mL). The reaction was washed once with water (25 mL) and the aqueous layer was extracted three times with dichloromethane (20 mL) until no orange color remained. The organic layer was dried with magnesium sulfate and concentrated in vacuo to afford alkyne 3 (99%, 691 mg) as a dark orange solid: 1H NMR (400 MHz, CDCl3) δ 7.41 (apparent s, 4H), 4.65 (t, J = 1.9 Hz, 2H), 4.35 (t, J = 1.9 Hz, 2H), 4.03 (s, 5H), 3.11 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 140.6, 132.3, 125.9, 119.2, 84.2, 84.1, 77.2, 69.9, 69.5, 66.7; FTIR (cm-1): 3286, 3090, 2104, 835, 811; GC/MS (CI) 286.1 (M)+, 165.1 (M-C5H5Fe)+; HRMS (EI+) m/z, calculated for [C14H18Fe]+: 286.0445; found: 286.0449.

(S2) A hot 200 mL Schlenk flask equipped with a magnetic stir bar and a rubber septum was attached to a double manifold and cooled under vacuum. The flask was backfilled with nitrogen, the septum was removed, and palladium (II) acetate (29.3 mg, 131 µmol), 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (SPhos, 107 mg, 261

µmol), K3PO4·H2O (6.01 g, 26.1 mmol), and ferrocene boronic acid (3.06 g, 13.3 mmol) were added. The septum was replaced, the flask was reattached to the double manifold, and evacuated and backfilled with nitrogen three times. Anhydrous toluene (89 mL) was added via syringe and the reaction was heated to 100°C in an oil bath. Once the reaction reached 100°C, ethyl 4-bromobenzoate (2.13 mL, 13.1 mmol) was added via syringe. The reaction remained at 100°C for 24 h. Once complete, the septum was removed and the reaction was cooled to rt and diethyl ether (50 mL) was added. The reaction was flushed through a silica gel plug to remove solids and concentrated in vacuo. The crude reaction mixture was purified by column chromatography (10% diethyl ether in hexanes) to afford ester S2 (86%, 3.75 g) as an orange solid: 1H NMR (400 MHz, CDCl3) δ 7.96 (d, J = 8.4 Hz, 2H), 7.51 (d, J = 8.4 Hz, 2H), 4.71 (t, J = 1.8 Hz, 2H), 4.41 – 4.34 (m, 4H), 4.03 (s, 5H), 1.40 (t, J = 7.1 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 166.8, 145.1, 129.8, 127.8, 125.7, 83.5, 70.0, 69.9, 67.0, 61.0, 14.6; FTIR (cm-1): 3106,

FeTMS

FeH

Fe

O

OEt

S4


2979, 1704, 1608, 1278, 832, 814; GC/MS (CI) 334.1 (M)+, 306.1 (M-C2H5)+; HRMS (EI+) m/z, calculated for [C19H18FeO2]+: 334.0656; found: 224.0650.

(S3) A hot, dry 200 mL round bottom flask equipped with a magnetic stir bar and a rubber septum was attached to a double manifold and cooled under vacuum. The flask was backfilled with nitrogen, the septum was removed, and ester S2 (3.70 g, 11.1 mmol) was added.

The septum was replaced, the flask was reattached to the double manifold, and evacuated and backfilled with nitrogen three times. Anhydrous toluene (111 mL) was added via syringe and the reaction was cooled to –78°C. Once cool, DIBAL (1.2M in toluene, 36.9 mL) was slowly added. The reaction was allowed to slowly warm to rt over 6 h. The reaction was recooled to 0°C and sodium sulfate decahydrate (2.00 g) was added and the slurry was allowed to stir for 1 h after which the reaction was filtered and concentrated in vacuo to afford alcohol S3 (2.82 g, 87%) as an orange solid: 1H NMR (400 MHz, CDCl3) δ 7.48 (d, J = 8.2 Hz, 2H), 7.29 (d, J = 8.2 Hz, 2H), 4.67 (d, J = 5.9 Hz, 2H), 4.64 (t, J = 1.9 Hz, 2H), 4.32 (t, J = 1.9 Hz, 2H), 4.04 (s, 5H), 1.63 (t, J = 5.9 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 139.0, 138.5, 127.4, 126.4, 85.2, 69.7, 69.1, 66.6, 65.5; FTIR (cm-1): 3314, 2936, 2872, 1527, 1424; APCI: 292.0 (M)+, 275.0 (M-OH)+; HRMS (EI+) m/z, calculated for [C17H16FeO]+: 292.0551; found: 292.0558.

(S4) A hot, dry 25 mL round bottom flask equipped with a magnetic stir bar and a rubber septum was attached to a double manifold and cooled under vacuum. The flask was backfilled with nitrogen, the septum was removed, and alcohol S3 (500 mg, 1.71 mmol) was added. The septum

was replaced, the flask was reattached to the double manifold, and evacuated and backfilled with nitrogen three times. Anhydrous CH2Cl2 (10 mL) was added via syringe and the reaction was cooled in an ice/NaCl bath to -10°C. Dry, degassed triethylamine (523 µL, 3.75 mmol) and methanesulfonyl chloride (291 µL, 3.75 mmol) were added via syringe. The reaction was allowed to warm to rt and remain at rt for 12 h. The septum was removed and crude reaction was concentrated in vacuo and purified by column chromatography (1:1 CH2Cl2: hexanes) to afford chloride S4 (405 mg, 76%) as an orange solid: 1H NMR (400 MHz, CDCl3) δ 7.46 (d, J = 8.2 Hz, 2H), 7.31 (d, J = 8.2 Hz, 2H), 4.64 (t, J = 1.8 Hz, 2H), 4.59 (s, 2H), 4.33 (t, J = 1.8 Hz, 2H), 4.04 (s, 5H); 13C NMR (101 MHz, CDCl3) δ 139.9, 135.0, 128.8, 126.5, 84.8, 69.8, 69.3, 66.7, 46.5; FTIR (cm-1): 3094, 1914, 1608, 1525, 1266, 1105, 842, 819; APCI 310.0 (M)+, 275 (M-Cl)+, 306 (M-Cl+OMe)+; HRMS (EI+) m/z, calculated for [C17H15FeCl]+: 310.0213; found: 310.0205.

(4) To a 50 mL round bottom flask equipped with a magnetic stir bar and fitted with a reflux condenser was added chloride S4 (405 mg, 1.30 mmol), sodium azide (211 mg, 3.25 mmol), and dimethylformamide (13 mL). The reaction was heated to 70°C for 15 h in an oil bath. Once

complete, the reaction was cooled to rt and dichloromethane (15 mL) was added. The solution was extracted three times with brine (15 mL), dried over magnesium sulfate, and concentrated in vacuo. The crude reaction was purified by column chromatography (2:1 hexanes: CH2Cl2) to afford azide 4 (371 mg, 90%) as a yellow solid: 1H NMR (400 MHz, CDCl3) δ 7.49 (d, J = 8.3 Hz, 2H), 7.24 (d, J = 8.4 Hz, 2H), 4.65 (t, J = 1.9 Hz, 2H), 4.34 – 4.30 (m, 4H), 4.04 (s, 5H); 13C NMR (101 MHz, CDCl3) δ 139.8, 132.9, 128.5, 126.6, 84.7, 69.8, 69.2, 66.7, 54.9; FTIR (cm-1): 3083, 2924, 2850, 2189, 2097, 1652, 1559, 818; APCI: 317.2 (M)+; HRMS (EI+) m/z, calculated for [C17H15FeN3]+: 317.0615; found: 317.0609.

Fe OH

Fe Cl

Fe N3

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Synthesis of Model Ferrocene Derivatives.

(Fc1) A hot 1-dram vial equipped with a magnetic stir bar and a Teflon-lined septum cap was attached to a double manifold using a syringe needle and cooled under vacuum. The vial was backfilled with nitrogen, the cap was removed, and copper

iodide (1.8 mg, 9.7 µmol), tertakis(triphenylphosphine)palladium (11.2 mg, 9.7 µmol), and 4-iodophenylferrocene (2) (47 mg, 121 µmol) were added. The septum was replaced, the vial was reattached to the double manifold, and evacuated and backfilled with nitrogen three times. Dry, degassed triethylamine (51 µL), anhydrous degassed dimethylformamide (2.4 mL), and phenylacetylene (27 µL, 242 µmol) were added via syringe. The reaction was heated in an oil bath to 80°C for 15 h. The reaction was cooled to rt, diluted with dichloromethane (10 mL), and extracted twice with saturated aqueous NaCl (10 mL). The organic layer was dried with magnesium sulfate and concentrated in vacuo. The crude reaction was purified by column chromatography (1% EtOAc: hexanes) to afford ferrocene Fc1 (37 mg, 84%) as an orange-red solid: 1H NMR (400 MHz, CDCl3) δ 7.56 - 7.52 (m, 2H), 7.45 (s, 4H), 7.38 - 7.32 (m, 3H), 4.67 (t, J = 1.9 Hz, 2H), 4.36 (t, J = 1.9 Hz, 2H), 4.05 (s, 5H); 13C NMR (101 MHz, CDCl3) δ 140.0, 131.8, 131.7, 128.5, 128.3, 126.0, 123.6, 120.5, 89.9, 89.5, 84.4, 69.9, 69.5, 66.7; FTIR (cm-1) 3080, 1595, 1526, 843, 820, 755, 688; APCI 362.1 (M)+; HRMS (EI+) m/z, calculated for [C24H18Fe]+: 362.0758; found: 362.0763.

(Fc2) This compound was prepared by an amended literature procedure.8 To a 10 mL round bottom flask equipped with a magnetic stir bar was added copper chloride (4.5 mg, 45 µmol), alkynyl ferrocene 3 (28.5 mg, 0.100 mmol), pyridine (4 mL), and phenyl acetylene (22

µL, 0.200 mmol). The reaction was heated in an oil bath to 60 °C for 3 h. After cooling to rt, the reaction was concentrated in vacuo. A saturated solution of NH4Cl (7 mL) was added and the aqueous layer was extracted twice with CH2Cl2 (7 mL). The organic layer was dried over magnesium sulfate and concentrated in vacuo. The crude reaction was purified by column chromatography (1% CH2Cl2: hexanes) to afford ferrocene Fc2 (18.9mg, 49%) as an orange solid: 1H NMR (400 MHz, CDCl3) δ 7.54 (dd, J = 7.8, 1.7 Hz, 2H), 7.44 (d, J = 1.2 Hz, 2H), 7.39 - 7.31 (m, 3H), 4.66 (t, J = 1.9 Hz, 2H), 4.37 (t, J = 1.8 Hz, 2H), 4.04 (s, 5H); 13C NMR (101 MHz, CDCl3) δ 141.3, 132.7, 132.6, 129.3, 128.6, 126.0, 122.1, 118.8, 84.0, 82.3, 81.7, 74.3, 74.0,

69.9, 69.7, 66.8, 58.5; FTIR (cm-1): 3091, 2919, 2213, 1522, 1486, 822, 814, 756, 691; APCI 386.1 (M)+; HRMS (EI+) m/z, calculated for [C26H18Fe]+: 386.0758; found: 386.0752. (Fc3) A hot 25 mL Schlenk flask equipped with a magnetic stir bar and a rubber septum was attached to a double

manifold and cooled under vacuum. The flask was backfilled with nitrogen, the septum was removed, and copper sulfate pentahydrate (4.0 mg, 15.8 µmol), ascorbic acid (4.2 mg, 23.7 µmol), and azide 4 (50.0 mg, 158 µmol) were added. The septum was replaced, the flask was reattached to the double manifold, and evacuated and backfilled with nitrogen three times. Anhydrous dimethylformamide (3.16 mL) and phenylacetylene (87.0 µL, 0.788 mmol) were added and the reaction was stirred at rt for 12 h. The septum was removed and CH2Cl2 (5 mL) was added. The reaction was washed twice with brine (10 mL) and the organic layer was dried over magnesium sulfate and concentrated in vacuo to afford ferrocene Fc3 (61.9 mg, 93%) as an orange solid: 1H NMR (400 MHz, CDCl3) δ 7.82 (d, J = 7.2 Hz, 2H), 7.70 (s, 1H), 7.48 (d, J = 8.2 Hz, 2H), 7.41 (t, J = 7.5 Hz, 2H), 7.36 - 7.29 (m, 1H), 7.23 (d, J = 8.2 Hz, 2H), 5.55 (s, 2H), 4.63 (t, J = 1.8 Hz, 2H), 4.33 (t, J = 1.8 Hz, 2H), 4.04 (s, 5H); 13C NMR (101 MHz, CDCl3) δ 148.4, 140.4, 132.1, 130.7, 129.0, 128.3, 126.8, 125.8, 119.6, 84.4, 69.8, 69.4, 66.7, 54.2; FTIR

Fe

Fe

Fe NNN

S6


(cm-1): 3118, 3091, 294, 1527, 1466, 817, 786, 694; APCI: 419.1 (M)+, 275.0 (M-C8H6N3); HRMS (EI+) m/z, calculated for [C25H21FeN3]+: 419.1085; found: 419.1078. Procedure for On-Surface Sonogashira Coupling: In a nitrogen-filled glove box copper iodide (2.4 mg, 12.6 µmol) tetrakis(triphenylphosphine)palladium(0) (13.8 mg, 12.0 µmol), iodophenylferrocene (58 mg, 150 µmol), triethylamine (63.6 µL, 45.0 µmol), and anhydrous dimethylformamide (3 mL) were added to a 20 mL vial. A piece of alkynyl modified carbon paper (CP2) with approximate dimensions of 1.0 × 0.5 cm was then added to this solution using forceps. The vial was capped with a polyethylene-lined cap and heated in an aluminum block to 80 °C for 15 min. The reaction solution was then allowed to cool to room temperature and the modified carbon substrate was removed from solution using forceps. The modified substrate was cleaned by pipetting 4 mL of dry acetonitrile onto both faces of the paper in order to remove excess reagents. The washed substrate was then placed in a clean vial and soaked in 8 mL of dry dimethylformamide for 1 hr. Following removal from the DMF with forceps, the carbon paper was washed again with 4 mL of dry acetonitrile and then soaked for an additional hour in 8 mL of acetonitrile. Following one final rinse with 4 mL of acetonitrile, the modified CP3 substrate was dried by evaporation under nitrogen for several minutes. The average atomic surface composition of CP3 was determined by XPS analysis as described above. High-resolution XPS spectra recorded for CP3 routinely showed the presence of iron (0.29 ± 0.08 %) with only trace levels of copper, iodine and palladium. XPS survey spectra showed the presence of low levels of residual silicon from the diazonium electrodeposition.

Procedure for On-Surface Glaser Coupling: Copper bromide (2.6 mg, 18.0 µmol), ferrocene derivative 2 (21.5 mg, 75 µmol), and pyridine (3 mL) were combined in a 20 mL vial under air. A piece of alkynyl modified carbon paper (CP2) with approximate dimensions of 1.0 × 0.5 cm was then added to this solution using forceps. The vial was loosely sealed with a polyethylene-lined cap and heated in an aluminum block at 60 °C for 3 hrs. After the reaction was cooled to room temperature, the carbon substrate was removed from vial using forceps and was transferred to a nitrogen-filled glovebox. The modified substrate was cleaned by pipetting 4 mL of dry acetonitrile onto both faces of the paper in order to remove excess reagents. The washed substrate was then placed in a clean vial and soaked in 8 mL of dry dimethylformamide for 1 hr. Following removal from the DMF with forceps, the carbon paper was washed again with 4 mL of dry acetonitrile and then soaked for an additional hour in 8 mL of acetonitrile. Following one final rinse with 4 mL of acetonitrile, the modified CP4 substrate was dried by evaporation under nitrogen for several minutes. The average atomic surface composition of CP4 was determined by XPS analysis as described above. High-resolution XPS spectra recorded for CP4 routinely showed the presence of iron (0.12 ± 0.05 %) with only trace levels of copper and bromine. XPS surveys showed the presence of low levels of residual silicon from the diazonium electrodeposition.

Procedure for On-Surface Huisgen Coupling: In a nitrogen-filled glovebox, copper sulfate pentahydrate (2.5 mg, 10.0 µmol), ascorbic acid (2.6 mg, 15.0 µmol), ferrocene derivative 4 (31.7 mg, 0.100 mmol) and dry dimethylformamide (2 mL) were combined in a 20 mL vial. A piece of alkynyl modified carbon paper (CP2) with approximate dimensions of 1.0 × 0.5 cm was then added to this solution using forceps and the vial was sealed with a polyethylene-lined cap. The reaction mixture was allowed to stand in the glovebox at room temperature. After 2 hrs, the modified carbon paper was removed from solution using forceps. The modified substrate was cleaned by pipetting 4 mL of dry acetonitrile onto both faces of the paper in order to remove excess reagents. The washed substrate was then placed in a clean vial and soaked in 8 mL of dry dimethylformamide for 1 hr. Following removal from the DMF with forceps, the carbon paper was washed again with 4 mL of dry acetonitrile and then soaked for an additional hour in 8 mL of acetonitrile. Following one final rinse with 4 mL of acetonitrile, the modified CP5 substrate was dried by evaporation under nitrogen for several minutes. The average atomic surface composition of CP5 was determined by XPS analysis as described above. High-resolution XPS

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spectra recorded for CP5 routinely showed the presence of iron (0.30 ± 0.05 %) with only trace levels of copper and iodine.

X-ray Structural Solution and Refinement. Crystals were selected, mounted on plastic mesh with viscous oil, cooled to 200 K, and diffraction data were collected either on a Bruker-AXS Smart Apex diffractometer (FC1 and Fc2) using Mo k-α radiation monochromated with graphite or on a Bruker AXS Apex 2 Duo diffractometer using Cu k-α radiation monochromated and focused using Goebel mirrors (Fc3). Data were corrected for absorption using multiscan methods (Fc1 and Fc2) or numerical methods (Fc3) [APEX2, Bruker-AXS Inc., 2007, Madison, Wisconsin, USA.] The structures were solved using direct methods and refined using full matrix least squares based on F2 with atomic scattering factors contained in the SHELXTL program suite.9 No symmetry higher than triclinic was observed for Fc2 and solution in the centrosymmetric space group option yielded chemically reasonable and computationally stable results of refinement. Systematic absences and unit cell parameters are consistent, uniquely, for P21/c for Fc1 and for P2 and P2/m for Fc3. Occupancy and the absence of a molecular plane were consistent with P2 for Fc3. The Flack parameter refined to essentially nil indicating the true hand of the data was determined, and an inspection of the unit cell-packing diagram did not reveal any overlooked symmetry. All non-hydrogen atoms were refined with anisotropic displacement parameters. All other hydrogen atoms were placed in calculated positions as idealized contributions.

S8


Fig. S-1 High-resolution XPS spectra recorded for the iron 2p region of carbon substrates modified by on-surface (a) Sonogashira coupling (CP3), (b) Glaser coupling (CP4) and (c) Huisgen coupling (CP5). Reported chemical shift values are averages of n = 4,8, and 4 replicate XPS analyses, respectively.

S9


Fig. S-2 High-resolution XPS spectra recorded for the nitrogen 1s region of (a) ferrocenyl azide (4) drop cast on a piece of bare carbon paper and (b) a sample of CP5 with triazole linkers. The lack of an XPS chemical state for nitrogen at 404.8 eV, which corresponds to the central nitrogen of the azide, clearly demonstrates triazole formation.

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Fig. S-3 (a) Cyclic voltammetry traces for CP5 directly after surface Huisgen reaction. The large anodic current on the first oxidative pass indicates the presence of Cu(I) bound to the surface. This peak decreases upon subsequent passes, revealing a stable ferrocene redox couple after approximately five passes. (b) High-resolution XPS spectra of copper 2p and iron 2p regions before (orange) and after (black) electrochemical removal of Cu. Note: electrochemical stripping of copper from the surface of CP5 was not concomitant with loss of immobilized iron.

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Fig. S-4 Fully labeled thermal ellipsoid plots of Fc1 – Fc3. Ellipsoids are shown at 50% probability and all hydrogen atoms are omitted for clarity.

S12


Table S1. Crystal Data and Structure Refinement Parameters for Fc1 – Fc3.

Fc1 Fc2 Fc3 Empirical formula C24H18Fe C26H18Fe C25H23FeN3 Formula weight 362.23 386.25 421.31 Temperature 200(2) K 200(2) K 200(2) K Crystal system Monoclinic Triclinic Monoclinic Space group P21/c P–1 P1211 Unit cell dimensions a = 21.166(4) Å a = 7.1257(6) Å α = 74.5870(10)° a = 11.3194(6) Å b = 9.9360(17) Å β = 92.968(3)° b = 9.7812(9)Å β = 81.2310(10)° b = 5.7682(3) Å β = 94.364(4)° c = 8.1878(14) Å c = 14.6087(13)Å γ = 70.4900(10)° c = 14.8959(8) Å Volume 1719.6(5) Å3 922.94(14) Å3 969.77(9) Å3 Z 4 2 2 Density (calculated) 1.399 mg/m3 1.390 mg/m3 1.443 mg/m3 Absorption coefficient 0.879 mm–1 0.824 mm–1 6.348 mm–1 F(000) 752 400 440 Crystal size 0.23 x 0.16 x 0.06 mm 0.55 x 0.50 x 0.12 mm 0.17 x 0.12 x 0.05 mm Θ range for data collection 1.93 to 27.56° 2.27 to 27.50° 2.98 to 72.40° Index ranges –27 ≤ h ≤ 27, –12 ≤ k ≤12, –10 ≤ l ≤10 –9 ≤ h ≤ 9, –12 ≤ k ≤12, –18 ≤ l ≤18 –13 ≤ h ≤ 3, –6 ≤ k ≤ 7, –18 ≤ l ≤ 18 Reflections collected 20821 12294 11621 Independent reflections 3965 [Rint = 0.0709] 4234 [Rint = 0.0344] 3644 [Rint = 0.0647] Completeness to Θ = 25.00° 99.9 % 99.9 % 99.5 % Absorption correction Numerical Numerical Numerical Max. and min. transmission 0.9516 and 0.8255 0.9076 and 0.6592 0.7504 and 0.4116 Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2 Full-matrix least-squares on F2 Data / restraints / parameters 3965 / 0 / 226 4234 / 0 / 244 3644 / 337 / 267 Goodness-of-fit on F2 1.043 1.020 1.081 Final R indices [I>2σ(I)] R1 = 0.0409, wR2 = 0.0813 R1 = 0.0309, wR2 = 0.0786 R1 = 0.0738, wR2 = 0.1971 R indices (all data) R1 = 0.0718, wR2 = 0.0941 R1 = 0.0363, wR2 = 0.0821 R1 = 0.0899, wR2 = 0.2146 Largest diff. peak and hole 0.289 and –0.342 e/Å–3 0.273 and –0.272 e/Å–3 0.341 and –0.347 e/Å–3

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References: (1) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.; Timmers, F. J.

Organometallics 1996, 15, 1518. (2) Anderson, S. Chem. Euro. J. 2001, 7, 4706. (3) Leroux, Y. R.; Fei, H.; Noël, J.-M.; Roux, C.; Hapiot, P. J. Am. Chem. Soc. 2010, 132,

14039. (4) Ambroise, A.; Wagner, R. W.; Rao, P. D.; Riggs, J. A.; Hascoat, P.; Diers, J. R.; Seth, J.;

Lammi, R. K.; Bocian, D. F.; Holten, D.; Lindsey, J. S. Chem. Mater. 2001, 13, 1023. (5) Patt, S. L.; Shoolery, J. N. J. Mag. Res. 1982, 46, 535. (6) Laviron, E. J. Electroanal. Chem. Interfac. 1979, 101, 19. (7) Bard, A. J.; Faulkner, L. R. Electrochemical Methods Fundamentals and Applications;

John Wiley & Sons: Hoboken, NJ, 2001. (8) Wang, L.-Y.; Suo, Q.-L.; Han, L.-M.; Wang, Y.-B.; Weng, L.-H. Polyhedron 2007, 26,

4981. (9) Sheldrick, G. Acta Cryst. A 2008, 64, 112.

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-1.0-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

9.28

4.98

2.00

2.06

3.92

0.26

4.01

4.34

4.34

4.35

4.64

4.65

4.65

7.39

Parameter ValueTitle AAG-02212-ASolvent CDCl3Temperature 298.2Number of Scans 16Receiver Gain 11Relaxation Delay 1.0000Pulse Width 15.0000Frequency 400.13Nucleus 1H

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-100102030405060708090100110120130140150160170f1 (ppm)

0.18

66.63

69.51

69.85

84.20

94.18

105.58

120.25

125.75

132.14

140.24

Parameter ValueTitle AAG-02212-ASolvent CDCl3Temperature 298.1Number of Scans 1024Receiver Gain 512Relaxation Delay 2.0000Pulse Width 9.2500Frequency 100.62Nucleus 13C

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S1

-1.0-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

1.00

5.24

2.04

2.16

4.31

3.11

4.03

4.34

4.35

4.35

4.65

4.65

4.66

7.41

Parameter ValueTitle AAG-02221-PSolvent CDCl3Temperature 298.2Number of Scans 16Receiver Gain 14Relaxation Delay 1.0000Pulse Width 15.0000Frequency 400.13Nucleus 1H

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3

-100102030405060708090100110120130140150160170180f1 (ppm)

66.69

69.53

69.85

77.19

84.13

84.17

119.24

125.90

132.29

140.60

Parameter ValueTitle AAG-02221-PSolvent CDCl3Temperature 298.1Number of Scans 1024Receiver Gain 512Relaxation Delay 3.0000Pulse Width 9.2500Frequency 100.62Nucleus 13C

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-1.0-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

2.93

4.69

3.98

1.88

2.00

1.95

1.39

1.40

1.42

4.03

4.35

4.37

4.38

4.39

4.39

4.41

4.71

4.71

4.72

7.26

7.50

7.52

7.95

7.97

4.304.354.404.454.504.554.604.654.704.754.80f1 (ppm)

3.98

1.88

4.35

4.37

4.38

4.39

4.39

4.41

4.71

4.71

4.72

Parameter ValueTitle AAG-03007-BSolvent CDCl3Temperature 298.1Number of Scans 16Receiver Gain 11Relaxation Delay 1.0000Pulse Width 15.0000Frequency 400.13Nucleus 1H

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-100102030405060708090100110120130140150160170180f1 (ppm)

14.55

60.95

67.00

69.89

69.95

83.51

125.71

127.77

129.80

145.10

166.82

Parameter ValueTitle AAG-03007-BSolvent CDCl3Temperature 298.2Number of Scans 1024Receiver Gain 512Relaxation Delay 3.0000Pulse Width 9.2500Frequency 100.62Nucleus 13C

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-1.0-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

1.00

4.95

1.94

2.00

2.09

2.01

2.08

1.61

1.63

1.64

4.04

4.31

4.32

4.32

4.64

4.64

4.65

4.67

4.68

7.28

7.30

7.47

7.49

4.24.34.44.54.64.74.8f1 (ppm)

1.94

2.00

2.09

4.31

4.32

4.32

4.64

4.64

4.65

4.67

4.68


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S3

-100102030405060708090100110120130140150160170180f1 (ppm)

65.48

66.63

69.08

69.73

85.16

126.41

127.35

138.48

138.95


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-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

5.01

1.98

2.19

2.00

2.25

2.10

4.04

4.32

4.33

4.33

4.59

4.64

4.64

4.64

7.30

7.32

7.45

7.47


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-100102030405060708090100110120130140150160170180f1 (ppm)

46.55

66.74

69.27

69.79

84.75

126.50

128.84

134.97

139.94


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-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

4.05

4.02

2.00

2.27

2.12

4.04

4.32

4.32

4.33

4.33

4.64

4.65

4.65

7.23

7.25

7.48

7.50

4.254.304.354.404.454.504.554.604.654.70f1 (ppm)

4.02

2.00

4.32

4.32

4.33

4.33

4.64

4.65

4.65


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-100102030405060708090100110120130140150160170180f1 (ppm)

54.85

66.69

69.23

69.77

84.74

126.56

128.49

132.91

139.75


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4

-1.0-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

5.20

2.00

2.04

3.53

4.14

2.38

4.05

4.35

4.36

4.36

4.67

4.67

4.68

7.26

7.34

7.35

7.35

7.36

7.36

7.37

7.37

7.45

7.53

7.54

7.54

7.55

7.56

Parameter ValueTitle AAG-02044-BSolvent CDCl3Temperature 298.2Number of Scans 16Receiver Gain 13Relaxation Delay 1.0000Pulse Width 15.0000Frequency 400.13Nucleus 1H

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-100102030405060708090100110120130140150160170180f1 (ppm)

66.65

69.50

69.86

84.36

89.54

89.88

120.45

123.59

125.96

128.26

128.49

131.67

131.77

140.01

Parameter ValueTitle AAG-02044-BSolvent CDCl3Temperature 298.1Number of Scans 1024Receiver Gain 512Relaxation Delay 3.0000Pulse Width 9.2500Frequency 100.62Nucleus 13C

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-1.0-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.510.0f1 (ppm)

4.83

1.94

2.00

3.52

4.05

2.16

4.04

4.36

4.37

4.37

4.66

4.66

4.67

7.32

7.33

7.33

7.34

7.36

7.37

7.37

7.38

7.41

7.44

7.44

7.46

7.53

7.53

7.55

7.55

Parameter ValueTitle AAG-03225-CSolvent CDCl3Temperature 298.2Number of Scans 16Receiver Gain 13Relaxation Delay 1.0000Pulse Width 15.0000Frequency 400.13Nucleus 1H

7.207.257.307.357.407.457.507.557.60f1 (ppm)

3.52

4.05

2.16

7.32

7.33

7.33

7.34

7.36

7.37

7.37

7.38

7.41

7.44

7.44

7.46

7.53

7.53

7.55

7.55

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Fc2

-100102030405060708090100110120130140150160170f1 (ppm)

58.46

66.75

69.72

69.91

74.04

74.31

81.74

82.26

83.95

118.79

122.05

125.99

128.58

129.27

132.60

132.70

141.34

Parameter ValueTitle AAG-03225-CSolvent CDCl3Temperature 298.2Number of Scans 1024Receiver Gain 512Relaxation Delay 3.0000Pulse Width 9.2500Frequency 100.62Nucleus 13C

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-1.0-0.50.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.09.5f1 (ppm)

5.15

1.97

2.00

2.09

2.29

1.23

2.33

2.20

1.02

2.14

4.04

4.33

4.33

4.34

4.63

4.63

4.64

5.55

7.22

7.24

7.30

7.32

7.34

7.39

7.41

7.43

7.47

7.49

7.70

7.81

7.82

7.17.27.37.47.57.67.77.87.9f1 (ppm)

2.29

1.23

2.33

2.20

1.02

2.14

7.22

7.24

7.30

7.32

7.34

7.39

7.41

7.43

7.47

7.49

7.70

7.81

7.82


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-100102030405060708090100110120130140150160170180f1 (ppm)

54.23

66.73

69.36

69.79

84.39

119.60

125.83

126.83

128.31

128.96

130.67

132.06

140.43

148.35


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125.83

126.83

128.31

128.96

130.67

132.06

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