Synthesis Schemes: 2+

Transcription

1 Supporting information for Modular Synthesis of Alkyne-Substituted Ruthenium Polypyridyl Complexes Suitable for "Click" Coupling James B. Gerken, Matthew L. Rigsby, Rose E. Ruther, Riviam J. Pérez- Rodríguez, Ilia A. Guzei, Robert J. Hamers*, Shannon S. Stahl* General Considerations Unless otherwise stated, all chemicals were obtained from Sigma-Aldrich and used without further purification. Electrochemical grade ( EC ) boron-doped diamond samples were purchased from Element VI Corporation. cis-ru(dmso) 4 Cl 2 was prepared according to literature procedure. 1 8 and 9 were synthesized in the fashion of the analogous tpy complexes. 2,3 [Ru(tpy)(bpm)(OH 2 )] 2+, used in electrochemical experiments to compare the redox properties of a parent complex with a triazole-modified derivative, was prepared following literature procedures. 4 Proton, carbon, and silicon MR chemical shifts are reported as δ relative to tetramethylsilane and are referenced either to that compound or to residual protons in the solvent. itrogen MR chemical shifts are reported as δ relative to liquid H 3 and are cross-referenced from a proton spectrum. Safety note: Complexes 4, 5, and 6 were typically isolated as perchlorate salts. Although these complexes displayed no untoward behavior during normal laboratory manipulations, a sample of 10 did deflagrate when struck with a hammer. It is suggested that the interested reader adapt the protocol described for the isolation of 4bpm as the hexafluorophosphate if further syntheses of these complexes are undertaken. Synthesis Schemes: 2+ Br TIPS Pd(PPh 3 ) 2 Cl 2, CuI benzene, i-pr 2 H 93% TIPS Ru(DMSO) 4 Cl 2 1,2-DCE 88% TIPS Cl Ru II Cl DMSO 1) AgO 3 2) bpm EtOH, reflux 85% TIPS Ru II Solv bpm Scheme S1. Route to 4bpm beginning with a Sonogashira alkynylation to the terpyridine ligand. Early route overall: 70% Br RuCl 3 Ethanol, reflux 87% Cl 3 Ru Br bpm, Et 3 75% EtOH/water, LiCl 67-83% Ru Cl Br Cl Ru Br AgO 3, LiClO 4 1:1 MeOH/water 69-72% Ru H 2 O Br TIPS PdCl 2 (PPh 3 ) 2, CuI i-pr 2 H, CH 3 C reflux, 2 h 77% Ru H 2 O Late route overall: 35% Scheme S2. Alternative route to 4bpm wherein the Sonogashira reaction is deferred until all desired ligands are present and the Ru III precursor has been reduced. TIPS S1

2 Synthetic details: Synthesis of 2: g 4 -bromo-2,2 :6,2 -terpyridine (1) (0.66 mmol, obtained from TCI America) was dissolved in 10 ml of degassed benzene. TIPS-acetylene (0.37 ml, 2.5 equiv.), CuI (7 mg, 0.01 equiv), Pd(PPh 3 ) 2 Cl 2 (0.026 g, 0.01 equiv), and 4 ml of i-pr 2 H were added and the reaction mixture was heated at reflux under nitrogen for 2 hours. The stirring mixture was then cooled to room temperature and filtered though silica. The filter cake was washed with 50 ml 10% EtOH in CH 2 Cl 2. Solvent was removed under vacuum, and the crude product was purified by column chromatography on silica gel with 2% EtOH:CH 2 Cl 2 to yield g ( 0.61 mmol, 93 %) of a yellowish solid with a musty, mushroom-like odor. The 1 H MR spectrum (300 MHz, CD 2 Cl 2 ) showed peaks at δ 8.70 (dd, J=4.8, 1.9 Hz, 2 H), 8.62 (dd, J=7.9, 1.2 Hz, 2 H), 8.50 (s, 2H), 7.89 (ddd, J=7.9, 7.6, 1.9 Hz, 2H), 7.38 (ddd, J=7.6, 4.8, 1.2 Hz, 2H), 1.20 (m, 21 H) ppm. The 13 C{ 1 H} MR spectrum (75 MHz, CD 2 Cl 2 ) showed peaks at δ , , , , , , ppm. The mass spectrum (EI) showed peaks at 413 (M + ), 370*, 342, 328, 314, 300. Attempts to determine the melting point of the product resulted in decomposition. Synthesis of 3: An 2 purged flask containing a solution of 200 mg of 2 (0.43 mmol) and cis-ru(dmso) 4 Cl 2 (210 mg, 0.43 mmol) in 1,2-dichloroethane was equipped with an 2 purged reflux condenser and heated at reflux for 10 hours in the dark. The mixture was concentrated to half volume on rotovap and stored in the refrigerator. A purple solid was collected by filtration, redissolved in CHCl 3, and precipitated by addition of ether, followed by refrigeration. The product was collected by filtration, washed well with ether, and dried under vacuum in a desiccator to give 243 mg of a purple solid. Yield: 88%. The 1 H MR spectrum (300 MHz, d 6 - DMSO) showed peaks at δ 9.00 (d, 2H), 8.75 (d, 2H), 8.62 (s, 2H), 8.15 (dd, 2H), 7.83 (dd, 2H), 1.2 (m, 21H). The mass spectrum (ESI, acetonitrile) showed peaks at 669 (M + CH 3 C - Cl - ), 649, 463*. Synthesis of 4tpy: 3 (102 mg, 0.15 mmoles) and AgO 3 (69 mg, 0.41 mmoles) were dissolved in 10 ml of degassed EtOH and refluxed under 2 for 3 hours. The mixture was cooled to room temperature and cannula transferred through a pipette filter containing celite under 2 to a refluxing EtOH solution of terpyridine (37 mg, 0.16 mmoles in 5 ml) and stirred at reflux overnight. The next morning, the reaction mixture was cooled to room temperature and 5 ml of 1 M aqueous aclo 4 was added. The mixture was concentrated to half volume and refrigerated. The precipitate was collected by filtration, washed with ether, dissolved in MeC, and solvent was removed to collect the product. Yield: 80%. 1 H-MR (500 MHz, CD 3 C) showed peaks at δ 8.77 (d, J=8.2 Hz, 2H), 8.77 (s, 2H), 8.55 (ddd, J=8.0, 1.4, 0.8 Hz, 2H), 8.50 (ddd, J=8.1, 1.3, 0.7 Hz, 2H), 8.43 (t, J=8.2 Hz, 1H), 7.92 (ddd, J=8.1, 7.6, 1.4 Hz, 2H), 7.91 (ddd, J=8.0, 7.7, 1.3 Hz, 2H), 7.36 (ddd, J=5.7, 1.3, 0.8 Hz, 2H), 7.36 (ddd, J=5.6, 1.4, 0.7 Hz, 2H), 7.18 (ddd, J=7.7, 5.7, 1.4 Hz, 2H), 7.15 (ddd, J=7.6, 5.6, 1.3 Hz, 2H), 1.27 (s, 21H). The 13 C{ 1 H} MR spectrum (126 MHz, CD 3 C) showed peaks at δ , , , , , , , , , , , , , , , , , , , ppm. The 29 Si{ 1 H} MR spectrum (99 MHz, CD 3 C) showed a peak at δ ppm. S2

3 Synthesis of 5tpy: 4tpy (50 mg, 0.05 mmoles) was dissolved in MeC and purged with 2 for 10 min. AgF (20 mg, 0.16 mmoles) was added and stirred under 2 in the dark overnight. The next morning, 250 µl of 1 M aqueous HClO 4 was added by syringe and stirred for 1 hour in the dark. 4 ml of 1 M aclo 4 was then added by syringe and allowed to stir for 10 minutes in the dark. The reaction mixture was filtered through celite and washed with 1 M aqueous aclo 4. The solid filter cake was redissolved in MeC and rotovapped to dryness to collect the product as a red-purple solid. Yield: 98%. 1 H-MR in CD 3 C δ 8.83 (s, 2H), 8.77 (d, 2H), (m, 4H), 8.43 (t, 1H), (m, 4H), (m, 4H), (m, 4H), 4.14 (s, 1H). Synthesis of 4bpm: 3 (67 mg, 0.1 mmol) was dissolved in 20 ml of EtOH. AgBF 4 (44 mg, 0.21 mmol) was added and the mixture was heated at reflux under 2 in the dark. After 2 hours, the reaction was allowed to cool to room temperature and was canula transferred through a celite filter under 2 into a refluxing EtOH solution of 2,2 -bipyrimidine (bpm, 16 mg, 0.1 mmol). After stirring at reflux under 2 for 2 hours, the reaction was allowed to cool to room temperature. 4 ml of water containing KPF 6 (0.182 g) were added and the mixture was rotovapped to reduce volume and stored in a refrigerator overnight. The precipitate was collected by filtration, washed with cold aqueous KPF 6 and then THF, and dried under vacuum in a desiccator. Yield: 85%. 1 H-MR in CD 3 C and CD 3 OD show a mixture of solvento- complexes otherwise similar to 4bpm produced from 10 by an alternative route (vide infra for full characterization of this compound). The mass spectrum (ESI, methanol) showed peaks at 708 (M ++ - i-pr + ), 660*, 415.4, (M ++ ), (M ++ /2). Synthesis of 5bpm: g of Ru-complex 4bpm (0.065 mmol) was dissolved in 10 ml of dry, degassed CH 3 C and allowed to stir under nitrogen. Silver fluoride (0.026 g, 3 equiv.) was added and the mixture was allowed to stir for 6 hours in the dark under nitrogen ml of 1 M aqueous perchloric acid was added and the mixture was allowed to stir for 30 minutes. 5 ml of aqueous aclo 4 was added and allowed to stir for 10 minutes. Under subdued light, the mixture was concentrated by rotary evaporation, filtered, washed with cold aqueous aclo 4 and deionized water, dissolved in CH 3 C, and concentrated by rotary evaporation. The solids were dissolved in 5 ml of CH 3 C, treated with ethyl ether to precipitate the product, and filtered to give g of a burgundy solid (100% yield). The 1 H MR spectrum (500 MHz, CD 3 C) showed peaks at δ (dd, J=5.6, 2.0 Hz, 1H), (dd, J=4.8, 2.0 Hz, 1H), (dd, J=4.7, 2.0 Hz, 1H), (s, 2H), (ddd, J=8.1, 1.3, 0.6 Hz, 2H), (dd, J=5.6, 4.8 Hz, 1H), (ddd, J=8.1, 7.7, 1.4 Hz, 2H), (ddd, J=5.6, 1.4, 0.6 Hz, 2H), (dd, J=5.8, 2.0 Hz, 1H), (ddd, J=5.6, 7.7, 1.3 Hz, 2H), (dd, J=5.8, 4.7 Hz, 1H), (s, 1H). A 1 H- 15 HMBC spectrum (500 MHz, d 6 -DMSO) gave the following correlations δ 9.96:247, 8.25:247, 8.25:300, 7.39:299, 7.39:238, 7.94:238, 9.11:266, 8.87:235, 7.96:235, 7.52:235 ppm (Figure S1). By vapor diffusion of ethyl ether into a CH 3 C solution, crystals suitable for X-ray crystallography were obtained. Diffraction data were solved to yield the structure shown in Figure 2. Synthesis of 4-t-butylphenyl azide 5 : A microwave reactor tube containing a magnetic stir-bar was charged with 3.75 ml of DMSO, g (0.2 equiv.) of proline, and 45 µl (0.2 equiv.) of 2 M aqueous aoh and mixed well g of CuI (0.2 equiv.) was added, producing a bluish color on dissolution, followed by 79.5 µl of 4-t-butylphenyl iodide. Then, g of sodium azide (3 equiv.) was added, the tube was capped, and placed in the microwave reactor. S3

4 The mixture was heated under temperature control and microwave irradiation to 100 C for 1 hour and let cool. The reaction mixture was diluted with 9 ml of water and extracted with three 5 ml portions of ethyl acetate. The combined organic extracts were back-extracted with three 5 ml portions of brine and dried over sodium sulfate. Rotary evaporation yielded g (quantitative yield) of a brown-colored liquid with an acrid odor subtly different from that of the starting aryl iodide. The 1 H MR spectrum (500 MHz, CDCl 3 ) showed peaks at δ (2H, OE to t- butyl), (2H) in a well-resolved A 2 X 2 coupling 6 (J=8.7, j=-0.3, J A =2.8, J B =2.2 Hz), (s, 9H) ppm. The IR spectrum (neat, ATR) showed peaks 7 at 2964, 2123, 2089, 1659, 1017, 831, 756, 707 cm -1. Subsequent synthesis by the method of Adam 8 yielded material with an identical odor and 1 H MR spectrum, and a 15 { 1 H} MR spectrum (50.7 MHz, ca. 1 M in CDCl 3 with ca. 1 mm Cr(acac) 3, 20 s relaxation time, 2808 transients, inverse-gated decoupling) with peaks at δ 243.5, 232.6, 90.2 ppm. 9 Synthesis of 6bpm: Complex 5bpm (10 mg, 0.01 mmole) and 4-t-butylphenyl azide (16 mg, 0.09 mmoles) were dissolved in 1 ml of DMSO in a flask equipped with a stir bar. To this mixture were added 10 mg of sodium ascorbate in 2 ml of an aqueous 1 mg/ml CuSO 4 /TBTA stock solution. The reaction was heated in a boiling water bath under 2 for 20 minutes. 5 After the reaction cooled to room temperature, 3 ml of aqueous aclo 4 was added and the mixture was chilled in an ice bath to precipitate a fuscous solid. This solid was collected by filtration to recover a crude product that was purified by prep-scale TLC (silica, eluted with CH 3 C:H 2 O:aClO 4 85:10:5) to give 2 mg of an amber-colored film (20 % yield, unoptimized). The 1 H-MR spectra (500 MHz, 2 -saturated CD 3 C) showed peaks at δ (dd, J=5.6, 1.4 Hz, 1H, COSY to 8.114), (dd, J=4.3, 1.4 Hz, 1H, COSY to 8.114), (s, 1H, OE to 9.135), (s, 2H, OEs to 9.309, 8.640), (dd, J=3.8, 1.0 Hz, 1H, COSY to 7.231), (d, J=8.2 Hz, 2H, OE to 9.135, COSY to 8.082), (dd, J=5.6, 4.3, 1H, COSY to 9.886, 9.376), (ddd, J=8.2, 7.6, 1.3 Hz, 2H, COSY to 8.640, 7.407), (A 2 X 2, J=9.0, j=0.3, J A =2.6, J B =2.4 Hz, 2H, COSY to 7.737), (dd, J=5.5, 1.3 Hz, 2H, COSY to 7.407), (dd, J=5.7, 1.0 Hz, 1H, COSY to 7.231), (A 2 X 2, J=9.0, j=0.3, J A =2.6, J B =2.4 Hz, 2H, OE to 1.412, COSY to 7.925), (dd, J=7.6, 5.5 Hz, 2H, COSY to 8.082, 7.855), (dd, J=5.7, 3.8 Hz, 1H, COSY to 8.848, 7.776), (s, 9H, OE to 7.737) ppm (Figure S6). A 1 H- 15 HMBC spectrum (500 MHz, O 2 -saturated CD 3 C) gave the following correlations δ 9.88:247, 9.31:362, 9.31:349, 9.31:258, 7.92:258, 9.13:260, 8.63:234, 7.85:234, 7.39:234, 7.77:238 ppm (Figure S7). The mass spectrum (ESI, methanol) showed peaks at (M ++ + ClO 4 - ), 366.6* (M ++ ). High-resolution mass spectrometry gave a peak at m/z , for C 37 H Ru is calculated. S4

5 ote: This alternative route was the originally developed synthesis to reach the TIPS-protected Ru complexes. The other route (Scheme S1) was found to be more generally useful, but this route is presented here for completeness and to guide any readers who find it better suited to their own needs. Synthesis of 8: g of 4 -bromo-2,2 :6,2 -terpyridine (1 mmol) was dissolved in 125 ml of ethanol g (1 mmol, 1 equiv.) of RuCl 3 3H 2 O was added and the mixture was heated to reflux for four hours followed by chilling in a freezer overnight. The resulting solids were isolated by filtration, washed thrice with ice-cold ethanol, once with ice-cold ether, and let dry to give g (0.87 mmol, 87%) of a dark material that was used without further characterization. Synthesis of 9: g of LiCl (1.60 mmol, 5.5 equiv.) was dissolved in 24 ml of a 75% ethanol/water mixture, followed by 47 mg (0.29 mmol, 1 equiv.) of 2,2'-bipyrimidine. Approximately 0.1 ml of triethylamine was added to the solution followed by g (0.28 mmol) of 8. ota bene, this order of addition is critical for optimal yield. The mixture became royal purple colored and was heated to reflux under nitrogen for four hours. Following filtration of the hot mixture, the solution was concentrated by rotary evaporation to ~ 5 ml and chilled in a refrigerator for 24 hours. The solids were isolated by filtration and washed sequentially with ice-cold portions of 3 M aqueous HCl, acetone, and ether and allowed to air-dry g (0.24 mmol, 83%) of a purple solid was obtained which gave an 1 H MR spectrum (300 MHz, D 2 O) showing peaks at δ (dd, 5.8, 2.0 Hz, 1H), 9.32 (dd, 4.8, 2.0 Hz, 1H), 8.85 (s, 2H), 8.74 (dd, 4.6, 1.9 Hz, 1H), 8.43 (dd, 8.2, 1.3 Hz, 2H), 8.18 (dd, 5.8, 4.8 Hz, 1H), 7.98 (ddd, 8.2, 7.7, 1.5 Hz, 2H), 7.83 (m, 3H), 7.37 (ddd, 7.7, 5.6, 1.3 Hz, 2H), 7.18 (dd, 5.8, 4.6 Hz, 1H) ppm. Synthesis of 10: g of LiClO 4 (1.5 mmol, 3 equiv.) was dissolved in 12 ml of deionized water, followed by the addition of 13 ml of methanol g of AgO 3 (1.25 mmol, 2.5 equiv) was added and allowed to dissolve followed by g of 9 (0.5 mmol). The solution was heated to reflux for two hours, filtered hot, and left under a flow of nitrogen to evaporate the methanol. The resulting solution was chilled and filtered with the solid being rinsed with ice-cold water and left to dry. From this, g of a wine-dark solid was obtained (0.36 mmol, 72%). The 1 H MR spectrum (500 MHz, D 2 O) showed peaks at δ 9.90 (dd, 5.8, 2.0 Hz, 1H), 9.37 (dd, 4.9, 2.0 Hz, 1H), 8.90 (s, 2H), 8.73 (dd, 4.7, 1.9 Hz, 1H), 8.46 (dd, 8.3, 1.1 Hz, 2H), 8.23 (dd, S5

6 5.8, 4.9 Hz, 1H), 8.04 (ddd, 8.3, 7.5, 1.6 Hz, 2H), 7.89 (dd, 5.6, 1.6 Hz, 2H), 7.81 (dd, 6.0, 1.9 Hz, 1H), 7.41 (ddd, 7.5, 5.6, 1.1 Hz, 2H), 7.18 (dd, 6.0, 4.7 Hz, 1H) ppm. Alternative synthesis of 4bpm from 10: g of 10 (0.1 mmol) was dissolved in 6 ml of acetonitrile and deoxygenated by bubbling with 2. TIPS-acetylene (70 µl, 3 equiv.), CuI (~1 mg, 0.06 equiv), Pd(PPh 3 ) 2 Cl 2 (6 mg, 0.06 equiv), and 2 ml i-pr 2 H were added and the reaction mixture was heated at reflux under nitrogen for 2 hours. The mixture was reduced by rotary evaporation and filtered through silica gel with acetonitrile followed by an acetonitrile/water/aclo 4 mixture. The filtrate was chromatographed on silica gel with an CH 3 C / 2% (5% aq. aclo 4 ) mixture. The first fraction was rotovapped and precipitated with water, chilled, filtered, redissolved in CH 3 C, and refiltered The green solution was treated with i-proh and i-pr 2 H, followed by reconcentration, precipitation by aq. aclo 4, and cold filtration. Dissolution in CH 3 C, filtration, and rotary evaporation gave g of semi-crude material. The first purple fraction was rotovapped, precipitated with water, and filtered cold. The precipitate was rinsed with deionized water and redissolved in CH 3 C, then rotovapped to give another g of semi-crude. The last fraction was rotovapped, precipitated with aq. aclo 4, filtered, washed with aq. aclo 4 then deionized water, redissolved in CH 3 C, and rotovapped to give g product. As the aqueous filtrate evaporated, a second crop of crystals appeared and was filtered to give g of product. The semi-crude fractions were combined, dissolved in 10 ml EtOH, treated with 40 mg of AgO 3, and let reflux for 1 hour. After cooling, the mixture was filtered through celite and rotovapped. Aqueous aclo 4 was added and the mixture was filtered after chilling. The precipitate was dissolved in CH 3 C and rotovapped to give g of product (0.071 g, mmol, 77% total yield). The 1 H MR spectrum (500 MHz, CD 3 C) showed peaks at δ 9.82 (dd, J=5.7, 2 Hz, 1 H), 9.38 (dd, J=4.9, 2.1 Hz, 1 H), 8.84 (dd, J=4.8, 2 Hz, 1 H), 8.60 (s, 2 H), 8.47 (dm, J=8 Hz, 2 H), 8.09 (dd, J=5.6, 4.7 Hz, 1H), 8.04 (td, J=6, 1.6 Hz, 2 H), 7.81 (dm, J=6.5 Hz, 2H), 7.67 (dd, J=5.8, 2 Hz, 1 H), 7.38 (m, 2 H), 7.31 (dd, J=5.8, 4.7 Hz, 1 H), 1.25 (m, 21 H) ppm. The mass spectrum (ESI, methanol) showed peaks at 701 (M ++ - CH 3 C + OH - ), 683, 619, 352* (M ++ - CH 3 C + CH 3 OH), 157. By slow evaporation of a CH 3 C/H 2 O solution, crystals suitable for X-ray crystallography were obtained. Diffraction data were solved to yield the structure shown in Figure S2. Table S1: Screening of TIPS-alkyne desilylation conditions. How not to do it, at least with TIPS-ac-tpy complexes: Fluoride source Solvent Result LiF, KF MeOH o reaction " CH 3 C " " DMSO " TBAF 10 THF Decomposition " DMSO " HF CH 3 C o reaction HF + AgO 3 " " KF + AgO 3 DMSO v. slow rxn, limited by KF solubility LiF + AgBF 4 CH 3 C slow rxn, decreasing rate KF + AgO 3 MeOH prompt rxn, ppt. Low yield isolated from ppt. in CH 3 C. S6

7 H assigned by comparison to COSY of TIPS-protected H 8 5 H 11 5 H 10 5 H 5 1 H 4 1 H 2 3 H 1 3 H 7 6 * * H 1 4 H 4 2 Figure S1. 1 H- 15 HMBC spectrum of compound 5bpm in d 6 -DMSO. Protons assigned by comparison to COSY of 4bpm. Figure S2. ORTEP rendered X-ray crystal structure of 4bpm, crystallized as the bis-perchlorate acetonitrile complex from acetonitrile/water. Protons, solvent molecules and counter-ions are not shown. itrogen atoms are shown in blue, ruthenium in peach, and silicon in lime. S7

8 Preparation of 5bpm tethered to diamond electrodes: Complex 5bpm was reacted with an azide-functionalized diamond electrode by a method reported previously which we reproduce below (Scheme S3): 11 Azide termination of diamond: Diamond samples were hydrogen terminated prior to use by hydrogen plasma treatment in a manner similar to that developed by Thoms and co-workers. 12 The diamond samples were exposed to a radio-frequency hydrogen plasma (~20 Watts) of pure hydrogen (20 Torr), while heating to ~800 C, for a period of approximately 30 minutes. XPS data (not shown) have established that this leaves the diamond samples terminated with C-H bonds. The resulting hydrogen-terminated diamond samples were removed from the vacuum system and covered with a layer of argon-purged 10-undecen-1-ol (Sigma Aldrich), covered with a fused silica window, and illuminated with UV light (254 nm, ~10 mw/cm 2 ) in a sealed cell under an argon atmosphere. The EC-grade bulk diamond and the BDDTF diamond graft at different rates; reaction times of hours (EC grade) and ~ 4 hours (BDDTF) were used to achieve similar coverages of the 11-undecene- 1-ol on the surfaces. After reaction the samples were sonicated in isopropanol and dried under 2. To convert the alcohol-terminated surface into the mesylate, samples were placed in a solution containing 10 ml methylene chloride, 1 ml triethylamine, and 1 ml methane sulfonyl chloride. The samples were reacted for 1 h in an ice bath. After reaction, the samples were sonicated in methylene chloride and dried under 2. Replacement of the mesylate intermediate with azide was accomplished by treating the samples overnight in a saturated solution of sodium azide in dry DMSO at 80 C. Click Functionalization of Azide-Terminated Diamond Surfaces: The azide-modified diamond samples were immersed in a solution of 100 µm alkyne-complex with 0.8 mm Cu(II)(tris-(benzyltriazolyl-methyl)amine)SO 4 (TBTA) and 15 mm sodium ascorbate in a 3:1 (v:v) DMSO:H 2 O mixture for 5 hours. The samples were sonicated in MeOH, CHCl 3, and isopropanol (IPA) for 30 seconds each and stored in isopropanol until further use. Coverage of 5bpm "clicked" on the electrode surface was calculated based on the ratio of the Ru(3d 5/2 ) and C(1s) XPS peaks. 11 This measurement gave a coverage of 6.6 x Ru/cm 2. Measurement of CV peak areas (Figure 4a in the main text) gave 5.3 x Ru/cm 2 assuming a single electron transfer process. These values are similar to those previously observed for 5tpy tethered to the same surface. ( ) 9 Diamond ( ) 9 5bpm [Cu II (TBTA)]SO 4 a ascorbate ( ) 9 Diamond Ru II Solv Scheme S3. Functionalization of azide-derivatized diamond surfaces by 5bpm. S8

9 Evidence of loss of 5bpm tethered to electrodes upon electrolysis: A. B. C. Figure S3. XPS of 5bpm-functionalized diamond surfaces before (A) and after (B) five minute electrolysis at 1.6 V. (C) (1s) XPS of 5bpm-functionalized diamond surfaces before and after five minute electrolysis at 1.6 V. Retention of a partial nitrogen signal is believed to originate from the presence of residual azide groups. Figure S4. CV of 5bpm-functionalized diamond electrode after a five-minute electrolysis at 1.6 V. S9

10 10000 C(1s) 8000 Counts Azide on surface Ru(3d) x o azide on surface x Binding Energy (ev) Figure S5. XPS of 5bpm-treated vertically aligned carbon nanofiber (VACF) electrode in the absence and presence of surface azide groups. S10

11 JBG /home/thoth/documents/stahl-stuff/ruthenium/nmr F1 [ppm] A F2 [ppm] JBG /home/thoth/documents/stahl-stuff/ruthenium/nmr F1 [ppm] F2 [ppm] B. S11

12 JBG /home/thoth/documents/stahl-stuff/ruthenium/nmr F1 [ppm] F2 [ppm] C. Figure S6. A) 1 H- 1 H DQFCOSY MR of complex 6bpm in CD 3 C. B) 1 H- 1 H OESY MR of complex 6bpm in CD 3 C. C) Expansion of (B). Positive-phase peaks are teal, negative-phase peaks are blue. S12

13 JBG /home/thoth/documents/stahl-stuff/ruthenium/nmr Click product F1 [ppm] Figure S7. 1 H- 15 HMBC MR of complex 6bpm in CD 3 C. The peaks at 1 H δ of ~2 and 15 δ of 241 and 176 ppm are free and bound acetonitrile respectively. Due to choice of spectral window, the triazole nitrogen resonances observed at 162 and 150 ppm have been folded from their resonances at 362 and 349 ppm. 13 Surface-tethering bibliography: A thorough review of the literature on covalent attachment of molecules to surfaces is beyond the scope of this communication. onetheless, the following references were readily at hand and illustrate the diversity of reactions employed at various surfaces. Through phosphonate and carboxylate linkers: (a) Frantz, R.; Durand, J.-O.; Lanneau, G. F.; Jumas, J.-C.; Olivier-Fourcade, J.; Cretin, M.; Persin, M. Eur. J. Inorg. Chem. 2002, (b) Hanson, E. L.; Schwartz, J.; ickel, B.; Koch,.; Danisman, M. F. J. Am. Chem. Soc. 2003, 125, (c) Grätzel, M. Inorg. Chem. 2005, 44, (d) Silverman, B. M.; Wieghaus, K. A.; Schwartz, J. Langmuir 2005, 21, (e) Bishop, L. M.; Yeager, J. C.; Chen, X.; Wheeler, J..; Torelli, M. D.; Benson, M. C.; Burke, S. D.; Pedersen, J. A.; Hamers, R. J. Langmuir 2012, 28, Reductive electrografting of diazonium compounds is often used to bind organic moieties to carbon surfaces: (a) Bélanger, D.; Pinson, J. Chem. Soc. Rev. 2011, 40, (b) dekrafft, K. E.; Wang, C.; Xie, Z.; Su, X.; Hinds, B. J.; Lin, W. ACS Appl. Matl. Interfac. 2012, 4, A similar reductive electrografting method can be employed with halides at silicon surfaces: Gurtner, C.; Wun, A. W.; Sailor, M. J. Angew. Chem. Int. Ed. 1999, 38, F2 [ppm] S13

14 Bipyridine ligands have been oxidatively attached to graphite surfaces via an abnormal Kolbe reaction but the stability of the resulting linkage is sub-optimal: Geneste, F.; Moinet, C.; Ababou-Girard, S.; Solal, F. Inorg. Chem. 2005, 44, Click reactions can be performed to surface-bound alkynes: Rohde, R. D.; Agnew, H. D.; Yeo, W.-S.; Bailey, R. C.; Heath, J. R. J. Am. Chem. Soc. 2006, 128, Even the thiol-ene reaction has been used: Zeng, K.; Guo, M.; Zhang, Y.; Qing, M.; Liu, A.; ie, Z.; Huang, Y.; Pan, Y.; Yao, S. Electrochem. Commun. 2011, 13, Evans, I. P.; Spencer, A.; Wilkinson, G. J. Chem. Soc. Dalton Trans. 1973, Sullivan, B. P.; Calvert, J. M.; Meyer, T. J. Inorg. Chem. 1980, 19, Takeuchi, K. J.; Thompson, M. S.; Pipes, D. W.; Meyer, T. J. Inorg. Chem. 1984, 23, Concepcion, J. J. Jurss, J. W.; Templeton, J. L.; Meyer, T. J. J. Am. Chem. Soc., 2008, 130, From methodology in: McInnis, C. "The Design, Synthesis, and Mechanistic Characterization of Quorum Sensing Modulators", Ph.D. Dissertation, University of Wisconsin- Madison, May a) Assigned via the method in: Martin, J.; Dailey, B. P. J. Chem. Phys. 1962, 37, b) Reported as doublets at similar chemical shifts in Lee, S.; Hua, Y.; Park, H.; Flood, A. H. Org. Lett. 2010, 12, Assigned by analogy to the analysis of phenyl azide in: Dyall, L. K.; Kemp, J. E. Aust. J. Chem. 1967, 20, Adapted from methodology in: Adam, D. "The synthesis and characterisation of halogen and nitro phenyl azide derivatives as highly energetic materials", Ph.D. Dissertation, Ludwig- Maximilans-Universität München, August Cf. spectra of phenyl azide in: a) Müller, J. Z. aturforsch. B 1979, 34, b) Kanjia, D. M.; Mason, J.; Banks, R. E.; Venayak,. D. J. Chem. Soc. Perkin Trans. II 1981, Diederich, F.; Rubin, Y.; Chapman, O. L.; Goroff,. S. Helv. Chim. Acta 1994, 77, Ruther, R. E.; Rigsby, M. L.; Gerken, J. B.; Hogendoorn, S. R.; Landis, E. C.; Stahl, S. S.; Hamers, R. J. J. Am. Chem. Soc. 2011, 133, Thoms, B. D.; Owens, M. S.; Butler, J. E.; Spiro, C. Appl. Phys. Lett. 1994, 65, Cf. shifts tabulated in: Claramunt, R. M; Sanz, D.; López, C.; Jiménez, J. A.; Jimeno, M. L.; ElGuero, J.; Fruchier, A. Magn. Reson. Chem. 1997, 35, S14

15 Collected MR Spectra: 2 (4 TIPS CC )trpy CHDCl2 H2O Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S8. 1 H MR of 2. S15

16 2 (4 TIPS CC )trpy ID Shift [ppm] J [Hz] M Connection J(1, 3) J(1, 4) J(2, 4) J(2, 3) J(3, 4) J(3, 1) J(3, 2) J(4, 2) J(4, 1) J(4, 3) Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S9. 1 H MR of 2, aromatic region. S16

17 (4 TIPS CC )trpy Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 2.00 Hz PC ppm Figure S C{ 1 H} MR of 2. S17

18 (4 TIPS CC TPY) Ru (DMSO)Cl2 DMSO at 2.5 pm, water at 3.3 ppm Current Data Parameters AME RPR fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S11. 1 H MR of cis-dichloro 3. S18

19 [rel] RPR fid 1 1 /home/thoth/documents/stahl-stuff/ruthenium/nmr/rpr fid RPR fid 1 1 /home/thoth/documents/stahl-stuff/ruthenium/nmr/rpr fid Scale : RPR fid 1 1 /home/thoth/documents/stahl-stuff/ruthenium/nmr/rpr fid Scale : RPR fid 1 1 /home/thoth/documents/stahl-stuff/ruthenium/nmr/rpr fid Scale : RPR fid 1 1 /home/thoth/documents/stahl-stuff/ruthenium/nmr/rpr fid Scale : [ppm] Figure S12. 1 H MR of isomerization of cis- to trans-dichloro 3. From top to bottom, 0, 1, 2, 3 days in d 6 -DMSO exposed to subdued lab illumination. Once formed, the trans-isomer appears to persist in solution. S19

20 Current Data Parameters AME JBG EXPO 1 PROCO 1 F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zg30 TD SOLVET CD3C S 16 DS 2 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 1H P usec PLW W SI SF MHz LB 0.30 Hz PC ppm Figure S13. 1 H MR of 4tpy. S20

21 Current Data Parameters AME JBG EXPO 1 PROCO 1 F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zg30 TD SOLVET CD3C S 16 DS 2 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 1H P usec PLW W SI SF MHz LB 0.30 Hz PC ppm Figure S14. 1 H MR of aromatic region of 4tpy. S21

22 Current Data Parameters AME JBG EXPO 2 PROCO F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zgpg30 TD SOLVET CD3C S 173 DS 4 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 13C P usec PLW W ======== CHAEL f2 ======== SFO MHz UC2 1H CPDPRG[2 waltz16 PCPD usec PLW W PLW W PLW W SI SF MHz LB 1.00 Hz PC ppm Figure S C{ 1 H} MR of 4tpy. S22

23 Current Data Parameters AME JBG EXPO 3 PROCO F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zgig TD SOLVET CD3C S 104 DS 4 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 29Si P usec PLW W ======== CHAEL f2 ======== SFO MHz UC2 1H CPDPRG[2 waltz16 PCPD usec PLW W PLW W SI SF MHz LB 2.00 Hz PC ppm Figure S Si{ 1 H} MR of 4tpy. The broad peak is from silica in the sample tube and probe. S23

24 Figure S17. 1 H MR of 5tpy. Inset depicts aromatic and alkynyl protons. S24

25 (4 TIPS CC TPY)Ru(DMSO)(BPM) in methanol after heating several times (from 3, see 4bpm made from 10 for clean spectra) * ppm Figure S18. 1 H MR of 4bpm. See below for cleaner material. S25

26 (4 TIPS CC TPY)Ru(DMSO)(BPM) in methanol after heating several times (mix) ppm ppm Current Data Parameters AME Gcosy_01.fid EXPO 1 PROCO 1 F1 Acquisition parameters TD 512 SFO MHz FIDRES Hz SW ppm FnMODE undefined SI 2048 SF MHz WDW SIE LB 0 Hz PC 1.40 F1 Processing parameters SI 512 MC2 QF SF MHz WDW States LB 0 Hz Figure S19. 1 H GCOSY MR of 4bpm. The couplings within the non-equivalent halves of the bipyrimidine ligand are indicated by solid and dotted lines, couplings within the terpyridine are denoted with dashes. See below for cleaner material. S26

27 4bpm from Sonogashira on 10 Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S20. 1 H MR of 4bpm. Produced by alternate route. S27

28 4bpm from Sonogashira on 10 Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S21. 1 H MR of aromatic region of 4bpm. Produced by alternate route. S28

29 Current Data Parameters AME JBG EXPO 2 PROCO 1 F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zg30 TD SOLVET CD3C S 64 DS 2 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 1H P usec PLW W SI SF MHz LB 0.60 Hz PC ppm Figure S22. 1 H MR of 5bpm. S29

30 4 t butylphenyl azide Current Data Parameters AME JBG EXPO 1 PROCO 1 F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zg30 TD SOLVET CDCl3 S 16 DS 2 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 1H P usec PLW W SI SF MHz LB 0.30 Hz PC ppm Figure S23. 1 H MR of 4-tert-butylphenyl azide. S30

31 4 t butylphenyl azide Current Data Parameters AME JBG EXPO 1 PROCO F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zg30 TD SOLVET CDCl3 S 16 DS 2 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 1H P usec PLW W SI SF MHz LB 0.30 Hz PC ppm Figure S24. 1 H MR of aromatic region of 4-tert-butylphenyl azide. S31

32 6, in presence of acetonitrile, ethyl acetate Current Data Parameters AME JBG EXPO 2 PROCO 1 F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zg30 TD SOLVET CD3C S 32 DS 2 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 1H P usec PLW W SI SF MHz LB 0.30 Hz PC ppm Figure S25. 1 H MR of 6. S32

33 6, in presence of acetonitrile, ethyl acetate Current Data Parameters AME JBG EXPO 2 PROCO 1 F2 Acquisition Parameters Date_ Time ISTRUM spect PROBHD 5 mm CPPBBO BB PULPROG zg30 TD SOLVET CD3C S 32 DS 2 SWH Hz FIDRES Hz AQ sec RG DW usec DE usec TE K D sec TD0 1 ======== CHAEL f1 ======== SFO MHz UC1 1H P usec PLW W SI SF MHz LB 0.30 Hz PC ppm Figure S26. 1 H MR of aromatic region of 6. S33

34 9 (4 Br tpy)(bpm)rucl Cl 2nd crop Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S27. 1 H MR of 9 in D 2 O with DSS. S34

35 9 (4 Br tpy)(bpm)rucl Cl 2nd crop Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S28. 1 H MR of aromatic region of 9 in D 2 O with DSS. S35

36 10 in D2O + DSS Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S29. 1 H MR of 10 in D 2 O with DSS. S36

37 10 in D2O + DSS Current Data Parameters AME JBG fid EXPO 1 PROCO 1 SI SF MHz LB 0.30 Hz PC ppm Figure S30. 1 H MR of aromatic region of 10 in D 2 O with DSS. S37