Supporting Information

© Wiley-VCH 2008

69451 Weinheim, Germany

S1

SUPPORTING INFORMATION FOR:

Ru-Hbpp Based Water Oxidation Catalysts Anchored into Conducting Solid Supports

Joaquim Mola, Elena Mas-Marza, Xavier Sala, Isabel Romero*, Montserrat Rodríguez, Clara Viñas, Teodor Parella and Antoni Llobet*

Experimental Details

[Ru2(µ-Cl)(µ-bpp)(t-trpy)2](PF6)2·3H2O, 1(PF6)2·3H2O. This compound was

prepared in the same manner as described for 1’, but using t-trpy instead of trpy

(see reference 5 of the main text). Yield: 0.160 g (36%). Anal. Calcd. for

C65H55ClF12N12O3P2Ru2·3H2O: C, 49.42; H, 3.51; N, 10.64; Found C, 49.11; H,

3.80, N, 10.43. IR: ν = 3090, 2920, 1625, 1390, 850 cm-1. 1H-NMR (500 MHz,

acetone-d6, 25 ºC): δ= 5.26 (s, H3), 6.10 (t, H1), 6.82 (t, H17), 6.84 (t, H2), 7.4 (d,

J5-6= 8.5 Hz, H5), 7.52 (d, J16-17= 5 Hz, H16), 7.64 (t, J14-13= J14-15= 4.5 Hz, H14),

7.83 (t, J18-19= J18-17= 7.5 Hz, H18), 7.96 (t, J13-12= J13-14= 7.5 Hz, H13), 8.06 (d, J6-

5= 8.5 Hz, H6), 8.28 (d, J19-18= 8 Hz, H19), 8.41 (d, J15-14= 4.5 Hz, H15), 8.52 (s,

H22), 8.71 (d, J12-13= 7.5 Hz, H12), 8.96 (s, H9). 13C-NMR (500 MHz, acetone-d6,

25ºC): δ = 52.1 (C3), 103.5 (C22), 108.1 (C1), 120.1 (C19), 120.3 (C9), 121.8

(C17), 122 (C2), 124 (C12), 127.3 (C14), 127.6 (C6), 128.2 (C5), 136 (C7), 137.3

(C18), 137.5 (C13), 141.4 (C4), 145.7 (C8), 148.4 (C21), 153.4 (C15), 153.9 (C16),

158.2 (C10), 158.6 (C20), 160 (C11). UV-vis [CH2Cl2; λmax/nm (ε/M-1cm-1)]: 285

(48318), 314 (40672), 383 (15902), 490 (12844), 516 (11500). E1/2

Ru(II,II)/Ru(II,III) (V): (CH2Cl2 + 0.1M TBAH) 0.71 and E1/2 Ru(II,III)/Ru(III,III) (V):

(CH2Cl2 + 0.1 M TBAH) 1.15 vs. SSCE.

[Ru2(µ-OAc)(µ-bpp)(t-trpy)2](PF6)2·4H2O, 2(PF6)2·4H2O. A sample of 0.083 g

(0.054 mmol) of 1·3H2O and 0.015 g (0.108 mmol) of sodium acetate were

dissolved in 20 mL of acetone:water (3:1) and heated at reflux for 2h. The resulting

solution was filtered and a few drops of saturated aqueous solution of NH4PF6

S2

added. Upon reducing the volume, a solid come out of the solution that was

washed with cold water and ether. Yield: 0.067g (80%). Anal. Calcd. for

C67H52F12N12O2P2Ru2·4H2O: C, 49.63; H, 3.73; N, 10.37; Found: C, 49.34; H, 3.59;

N, 10.08. IR: ν = 3090, 2920, 1625, 1390, 1230, 850 cm-1. 1H-NMR (500 MHz,

acetone-d6, 25 ºC): δ= 0.49 (s, H24), 5.31 (s, H3), 6.12 (t, H1), 6.85 (t, H2), 6.85 (t,

H2), 6.85 (t, H17), 7.47 (d, H5), 7.48 (d, H16), 7.55 (t, J14-13= J14-15= 7 Hz, H14),

7.76 (t, J18-19= J18-17= 7.5 Hz, H18), 8.06 (t, J13-12= J13-14= 8 Hz, H13), 8.16 (d, J6-5=

8 Hz, H6), 8.23 (d, J19-18= 7.5 Hz, H19), 8.48 (d, J15-14= = 5.5 Hz, H15), 8.57 (s,

H22), 8.84 (d, J12-13= 8 Hz, H12), 9.08 (s, H9). 13C-NMR (500 MHz, acetone-d6,

25ºC): δ = 25.6 (C24), 53 (C3), 102.5 (C22), 109.1 (C1), 120.4 (C19), 121.1 (C9),

121.8 (C2), 121.8 (C17), 124.6 (C12), 128.2 (C14), 128.6 (C6), 128.9 (C5), 136.8

(C18), 138.1 (C13), 138.8 (C7), 142.1 (C4), 146.5 (C8), 152.3 (C21), 153.7 (C16),

154.7 (C15), 157.3 (C20), 160.4 (C10), 160.4 (C11), 192.2 (C23). UV-vis [CH2Cl2;

λmax/nm; (ε/M-1cm-1)]: 285 (67297), 316 (57875), 370 (26918), 499 (15814), 547

(15141). E1/2 Ru(II,II)/Ru(II,III) (V): (CH2Cl2 + 0.1M TBAH) 0.67 and E1/2

Ru(II,III)/Ru(III,III) (V): (CH2Cl2 + 0.1M TBAH) 1.01 vs. SSCE.

For the NMR assignments of 1 and 2, we use the labeling scheme indicated in

Figure S1.

The anionic dicarbollide Cobalt complex containing a covalently bonded N-

substituted pyrrole monomer 4 was prepared according to literature procedures

(Masalles, C.; Llop, J.; Viñas, C.; Teixidor, F. Adv. Mat. 2002, 14, 826 and Llop, J.;

Masalles, C.; Viñas, C.; Teixidor, F.; Sillanpää, R.; Kivekäs, R. Dalton Trans.,

2003, 556).

Electrochemistry. Electrochemical experiments were performed in an IJ-

Cambria IH-660 potentiostat using a three electrode cell. Vitreous carbon sponge

(VCS) or fluorine-doped tin oxide (FTO) electrodes were used as working

electrodes, platinum plate (1x1 cm) as auxiliary and SSCE as the reference

electrode. All cyclic voltammograms presented in this work were recorded under

S3

nitrogen atmosphere unless explicitly mentioned. For electropolymerization

experiments, the complexes were dissolved in previously degassed CH2Cl2

containing 0.1 M n-Bu4N+PF6- (TBAH) as supporting electrolyte, and several

(between 5 and 30) consecutive cycles in a potential range from 0.0 to 1.2 V were

performed. The concentration of the complexes was approximately 0.2 mM. The

generated films were first transferred to a clean electrolyte CH2Cl2 solution and

further cycled 4-5 times, and finally were dipped in a 0.1 M triflic acid aqueous

solution for three days to achieve hydrolysis of the acetate bridging ligand. The

amount of catalyst supported was estimated from the intensity of the corresponding

two-electron III-III/II-II electrochemical wave in 0.1 M triflic acid solution.

Coulombimetric experiments for electrocatalytic generation of oxygen were

carried out in a Methrom cell containing 140 mL of 0.1 M triflic acid equip with

reference electrode (SSCE) and a platinum auxiliary electrode (surface area 2X1

cm2) with an applied potential of 1.17 V. The working electrode consisted on

VCS/poly-3 containing 13.0 nmols. The formation of molecular oxygen was

confirmed by the CV experiments showing a reduction wave at – 0.5-0.6 V due to

the superoxide formation which was not observed in the blank experiment.

Measurement of O2. In homogeneous phase oxygen evolution was

measured analyzing the concentration of the gas phase using a GC with TCD

detector. In this case the reactions are finished in less than 30 minutes. In

heterogeneous phase oxygen evolution was measured in solution with a

Hansatech Oxygraph System and the measurements were done during periods of

12-14 hours. See figure S7.

S4

Scheme S1. Synthetic pathway

2 [RuIIICl3(t-trpy)]

i)LiCl, NEt3ii)bpp-

4h reflux in MeOH

[Ru2II(µ-Cl)(bpp)(t-trpy)2]2+

2h reflux inwater:acetone (1:3)

H+

[Ru2II(µ-OAc)(bpp)(t-trpy)2]2+

1 2

[Ru2II(bpp)(t-trpy)2(H2O)2]3+

3

NaOAc

S5

Table S1. UV-vis spectroscopic features for the complex 3’ and its higher oxidation states species

generated with Ce(IV) measured at pH = 1.0 in a 0.1 M solution of triflic acid.

Complex λmax, nm (ε, M-1cm-1)

[Ru2II,II(bpp)(trpy)2(OH2)2]

3+

271.0(55372), 313.0(57484), 471.9

(11295),356.0(19192), 490.0(10468)

[Ru2II,III(bpp)(trpy)2(OH2)2]

4+ 272.1(50964), 312.0(46327), 465.1(8173)

sh at 377

wide band centered at a 574

[Ru2III,III(bpp)(OH)(trpy)2(OH2)]

4+ 272.1(1.058), 312.0(47337), 476.0(2617)

wide band centered at 549

[Ru2III,IV(bpp)(OH)2(trpy)2]

4+ 273.0(48531), 312.0(47337), 476.0(2250),

540(2204)

Table S2. E1/2 redox potentials for the complex 3’ extracted from cyclic voltammetry experimentes

at pH = 1.0 in a 0.1 M solution of triflic acid.

Redox couple E1/2 (V) vs. SSCE

RuIII-RuII/RuII-RuII 0.58

?E=110mV

RuIII-RuIII/RuIII-RuII 0.64

?E= 60 mV

RuIV-RuIII/RuIII-RuIII 0.88

?E= 100 mV

S6

Figure Captions.

- Figure S1. Drawings of: (a) complex 1, (b) complex 2.

- Figure S2. 1D and 2D NMR spectra (500 MHz, 298 K, acetona-d6) for complex 1:

(a) 1H-NMR, (b) COSY, (c) ROESY, (d) HSQC.

- Figure S3. 1D and 2D NMR spectra (500 MHz, 298 K, acetona-d6) for complex 2:

(a) 1H-NMR, (b) COSY, (c) ROESY, (d) HSQC.

- Figure S4. a) Growth of a VCS/poly-2 film (electrode volume, 2.0 x 0.7 x 0.7 cm;

pore size grade = 10 PPI) upon 5 repetitive scans from 0.0 to 1.2 V vs. SSCE in

0.2 mM 2, 0.1 M TBAH, CH2Cl2 (υ = 0.05 V·s-1). b) Five repetitive scans of the

transferred film generated in (a), after soaking it in a 0.1 M CF3SO3H solution for

three days (formation of a VCS/poly-3 film).

- Figure S5. a) Five repetitive scans for the FTO/poly-3 film (electrode area,1.0 x

1.0 cm; Γ Ru = 1.0 x 10-9 mol cm-2; see Figure 2 in the main text for the generation

of the FTO/poly-2 precursor) upon transferring it to a 0.1 M CF3SO3H solution after

three days soaking in the same media. b) CV for the analogous

[Ru2(bpp)(trpy)2(H2O)2]3+ 3’, complex in CF3SO3H 0.1 M solution. c) UV-vis spectra

of the different oxidation states generated chemically using Ce(IV) from the

FTO/poly-3 film in 0.1 M CF3SO3H solution. d) UV-vis spectra for the analogous

[Ru2(bpp)(trpy)2(H2O)2]3+ 3’, complex in CF3SO3H 0.1 M solution.

- Figure S6. a) Growth of a FTO/poly-(2-co-4) film upon 15 repetitive scans from

0.0 to 1.2 V vs. SSCE of a solution containing 0.2 mM 2, 0.2 mM 4, and 0.1 M

TBAH in CH2Cl2 (υ = 0.05 V·s-1). b) Five repetitive scans of the transferred film

generated in (a), after soaking it in a 0.1 M CF3SO3H solution for three days

(formation of a FTO/poly-(3-co-4) film (electrode area 1.0 x 1.0 cm2; ΓRu = 0.5 x 10-

S7

9 mol·cm-2)). c) UV-vis spectra for the FTO/poly-(3-co-4) film after 3 three soaking

in 0.1 M CF3SO3H solution.

- Figure S7. a) Oxygen evolution measured with a Hansatech Oxygraph System for

water oxidation caytalyzed by a FTO/poly-(3-co-4) film with Ce(IV) after 2

reutilizations (see main text for details in Table 1 entry 5). b) Background

experiment performed with 3.64 x 10-6 mols Ce(IV) in 2 mL total volume.

- Figure S8. Spectral changes for FTO/poly-3 film during catalytic reaction with a

Ce(IV):Ru-cat molar ratio of 3600:1 (1 nmol Ru catalyst anchored)

- Figure S9. Spectral changes for FTO/poly-(3-co-4) film after two reutilizations of

the catalytic system with a Ce(IV):Ru-cat molar ratio of 3600:1 in each experiment

(0.5 nmol Ru catalyst anchored).

- Figure S10. Cyclic voltammograms of VCS/poly-3 film: a) before and after the catalytic

reaction, b) CV obtained after the catalytic reaction in homogeneous phase using 3’.

- Figure S11. Intensity vs. time curves obtained applying a 1.17 V vs. SSCE potential to a

VCS/poly-3 film (blue) and to a similar VCS electrode without the poly-3 catalyst (pink).

S8

Figure S1. Drawings of: (a) complex 1, (b) complex 2.

(a)

1

2

3 4

5 6

7

8

9 10

11

12

13 14

15

16

17 18 19

20 21 22

Ru

N

NNN

Ru

N

N

N

Cl

N

N

N NN

(b)

Ru

N

NNN

Ru

N

N

N

N

N

N NN

OO

1

2

3 4

5 6

7

8

9 10

11

12

13 14

15

16 17

18 19

20 21

22

S9

Figure S2. 1D and 2D NMR spectra (500 MHz, 298 K, acetona-d6) for complex 1: (a) 1H-

NMR, (b) COSY, (c) ROESY, (d) HSQC.

(a)

5.56.06.57.07.58.08.59.0 ppm

(b)

ppm

5.05.56.06.57.07.58.08.59.0 ppm

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

S10

(c)

ppm

5.05.56.06.57.07.58.08.59.0 ppm

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

S11

(d)

ppm

5.56.06.57.07.58.08.59.09.5 ppm

50

60

70

80

90

100

110

120

130

140

150

S12

Figure S3. 1D and 2D NMR spectra (500 MHz, 298 K, acetona-d6) for complex 2:

(a) 1H-NMR, (b) COSY, (c) ROESY, (d) HSQC.

(a)

5.56.06.57.07.58.08.59.0 ppm

(b)

ppm

6.57.07.58.08.59.0 ppm

6.0

6.5

7.0

7.5

8.0

8.5

9.0

S13

(c)

ppm

6.57.07.58.08.59.0 ppm

6.0

6.5

7.0

7.5

8.0

8.5

9.0

S14

(d)

ppm

123456789 ppm

20

40

60

80

100

120

140

S15

Figure S4. a) Growth of a VCS/poly-2 film (electrode volume, 2.0 x 0.7 x 0.7 cm;

pore size grade = 10 PPI) upon 5 repetitive scans from 0.0 to 1.2 V vs. SSCE in

0.2 mM 2, 0.1 M TBAH, CH2Cl2 (υ = 0.05 V·s-1). b) Five repetitive scans of the

transferred film generated in (a), after soaking it in a 0.1 M CF3SO3H solution for

three days (formation of a VCS/poly-3 film).

(a)

-8,00E-04

-4,00E-04

0,00E+00

4,00E-04

8,00E-04

0 0,2 0,4 0,6 0,8 1 1,2 1,4

potential (V)

Cu

rren

t (A

)

(b)

-6,00E-04

-4,00E-04

-2,00E-04

0,00E+00

2,00E-04

4,00E-04

6,00E-04

0 0,2 0,4 0,6 0,8 1 1,2 1,4

potential (V)

Cu

rren

t (A

)

S16

- Figure S5. a) Five repetitive scans for the FTO/poly-3 film (electrode area,1.0 x

1.0 cm; Γ Ru = 1.0 x 10-9 mol cm-2; see Figure 2 in the main text for the generation

of the FTO/poly-2 precursor) upon transferring it to a 0.1 M CF3SO3H solution after

three days soaking in the same media. b) CV for the analogous

[Ru2(bpp)(trpy)2(H2O)2]3+ 3’, complex in CF3SO3H 0.1 M solution. c) UV-vis spectra

of the different oxidation states generated chemically using Ce(IV) from the

FTO/poly-3 film in 0.1 M CF3SO3H solution. d) UV-vis spectra for the analogous

[Ru2(bpp)(trpy)2(H2O)2]3+ 3’, complex in CF3SO3H 0.1 M solution.

S17

(a)

-1,50E-04

-1,00E-04

-5,00E-05

0,00E+00

5,00E-05

1,00E-04

1,50E-04

0 0,2 0,4 0,6 0,8 1 1,2 1,4

potential (V)

Cu

rren

t (A

)

(b)

- 4

- 2

0

2

4

6

0 0,2 0,4 0,6 0,8 1 1,2E (V)

I x 1

0-6 (A

)

S18

(c)

(d)

II- II II- III

III- III

III- IV 0

0,5

1

1,5

2

2,5

250 350 450 550 650 750

Wavelength (nm)

Abs

orba

nce

0

0,5

1

1,5

2

250 350 450 550 650

Wavelength (nm)

Abs

orba

nce

II-II II-III

III-IV

III-III

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

320 420 520 620 720

λ (nm)

Ab

sorb

ance

S19

Figure S6. a) Growth of a FTO/poly-(2-co-4) film upon 15 repetitive scans from 0.0

to 1.2 V vs. SSCE of a solution containing 0.2 mM 2, 0.2 mM 4, and 0.1 M TBAH in

CH2Cl2 (υ = 0.05 V·s-1). b) Five repetitive scans of the transferred film generated in

(a), after soaking it in a 0.1 M CF3SO3H solution for three days (formation of a

FTO/poly-(3-co-4) film (electrode area 1.0 x 1.0 cm2; ΓRu = 0.5 x 10-9 mol·cm-2)). c)

UV-vis spectra for the FTO/poly-(3-co-4) film after 3 three soaking in 0.1 M

CF3SO3H solution.

(a)

-1,80E-04

-1,20E-04

-6,00E-05

0,00E+00

6,00E-05

1,20E-04

1,80E-04

0 0,2 0,4 0,6 0,8 1 1,2

potential (V)

Cu

rren

t (A

)

S20

(b)

-1,00E-04

-5,00E-05

0,00E+00

5,00E-05

1,00E-04

0 0,2 0,4 0,6 0,8 1 1,2 1,4

potential (V)

Cu

rren

t (A

)

(c)

0

0,2

0,4

0,6

320 370 420 470 520 570 620 670 720 770

λ (nm)

Ab

sorb

ance

S21

Figure S7. a) Oxygen evolution measured with a Hansatech Oxygraph System for

water oxidation caytalyzed by a FTO/poly-(3-co-4) film with Ce(IV) after 2

reutilizations (see main text for details in Table 1 entry 5). b) Background

experiment performed with 3.64 x 10-6 mols Ce(IV) in 2 mL total volume.

Figure S7. (a)

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18

time (hours)

nm

ols

O2/

ml

1st reaction

2nd reaction

3rd reaction

(b)

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18

time (hours)

nm

ols

O2/

ml

background

S22

Figure S8. Spectral changes for FTO/poly-3 film during catalytic reaction with a

Ce(IV):Ru-cat molar ratio of 3600:1 (1 nmol Ru catalyst anchored)

0

0,2

0,4

0,6

0,8

1

320 370 420 470 520 570 620 670 720 770

λ (nm)

Abs

orba

nce

before reaction

1st reaction

S23

Figure S9. Spectral changes for FTO/poly-(3-co-4) film after two reutilizations of

the catalytic system with a Ce(IV):Ru-cat molar ratio of 3600:1 in each experiment

(0.5 nmol Ru catalyst anchored).

0

0,2

0,4

0,6

320 370 420 470 520 570 620 670 720 770

λ (nm)

Ab

sorb

ance

before rx1st reaction2nd reaction3rd reaction

S24

Figure S10. Cyclic voltammograms of VCS/poly-3 film: a) before and after the catalytic

reaction, b) CV obtained after the catalytic reaction in homogeneous phase using 3’.

-6,00E-04

-4,00E-04

-2,00E-04

0,00E+00

2,00E-04

4,00E-04

6,00E-040,000 0,200 0,400 0,600 0,800 1,000

potential (V)

Cur

rent

(A

)

after reactionbefore reaction

Figure S10. (b)

-0,00012

-0,00007

-0,00002

0,00003

0,00008

0,00013

0,00018

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

potential (V)

Cu

rren

t (A

)

S25

Figure S11. Intensity vs. time curves obtained applying a 1.17 V vs. SSCE potential to a

VCS/poly-3 film (pink) and to a similar VCS electrode without the poly-3 catalyst (blue).

0,00E+00

2,00E-04

4,00E-04

6,00E-04

8,00E-04

1,00E-03

1,20E-03

1,40E-03

1,60E-03

1,80E-03

2,00E-03

0 1000 2000 3000 4000 5000

Time (s)

Cu

rren

t (A

)