carboxy derivatised ir(iii) complexes: synthesis ...avishek paul, nivedita das, yvonne halpin,...

- 1 -

Supporting Information

_____________________________________________________________________

Carboxy Derivatised Ir(III) Complexes: Synthesis, Electrochemistry, Photophysical Properties and Photocatalytic

Hydrogen Generation

Avishek Paul, Nivedita Das, Yvonne Halpin, Johannes G. Vos* and Mary T. Pryce*

*School of Chemical Sciences, Dublin City University, Dublin 9, Ireland_____________________________________________________________________

Index

Figure S1: 1H NMR (DMSO-d6, 400 MHz) of ppy-COOH 3

Figure S2: 1H NMR (DMSO-d6, 400 MHz) of ppy-COOEt 3

Figure S3: 1H NMR(Acetonitrile-d6, 400 MHz) of

[Ir(ppy-COOEt)2(dceb)](PF6) 4

Figure S4: COSY NMR (Acetonitrile-d3, 400 MHz) of

[Ir(ppyCOOEt)2(dceb)](PF6) 4

Figure S5: 1H NMR (Acetonitrile-d6, 400 MHz) of

[Ir(ppy-COOEt)2(bpy)](PF6) 5

Figure S6: 2D COSY NMR(Acetonitrile-d6, 400 MHz) of

[Ir(ppy-COOEt)2(bpy)](PF6) 5


[Ir(ppy-COOEt)2(dpb)](PF6) 6


[Ir(ppy-COOEt)2(dpb)](PF6) 6


[Ir(ppy-COOEt)2(5Brbpy)](PF6) 7

Figure S10: COSY NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-

COOEt)2(5Brbpy)](PF6) 7


[Ir(ppy-COOEt)2(bpp)](PF6) 8


[Ir(ppy-COOEt)2(bpp)](PF6) 8

Figure S13: Chemical shifts of protons (ppy-COOEt) in different

iridium complexes. 1H NMR(Aceteonitrile-d3, 400 MHz);

Electronic Supplementary Material (ESI) for Dalton Transactions. This journal is © The Royal Society of Chemistry 2015Electronic Supplementary Material (ESI) for Dalton Transactions.This journal is © The Royal Society of Chemistry 2015

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(A) [Ir(ppy-COOEt)2(dceb)](PF6) ;

(B) [Ir(ppy-COOEt)2(bpy)](PF6) ;

(C) [Ir(ppy-COOEt)2(dpb)](PF6) ;

(D) [Ir(ppy-COOEt)2(5Brbpy)](PF6) ;

(E) [Ir(ppy-COOEt)2(bpp)](PF6) 9

Figure S14: 1H NMR (DMSO-d6, 400 MHz) of [Ir(ppy-COOEt)2Cl]2 10

Figure S15a: UV-Vis spectra of [Ir(ppy-COOEt)2Cl]2 was recorded

in acetonitrile at room temperature. Concentration of

the solution is ~10-5 M. 10

Figure S15b: UV-Vis spectra of iridium complexes recorded

in acetonitrile at room temperature. Concentration of

the solutions are ~10-5 M. 11

Figure S16: Life time experiment and kinetic fit graph of

[Ir(ppy-COOEt)2(µ-Cl)]2. Life time experiment was recorded

in nitrogen purged DCM solution at room temperature 12


[Ir(ppy-COOEt)2(bpy)](PF6). Life time experiment was recorded



[Ir(ppy-COOEt)2(bpp)](PF6). Life time experiment was recorded



[Ir(ppy-COOEt)2(5Brbpy)](PF6). Life time experiment was recorded



[Ir(ppy-COOEt)2(dpb)](PF6). Life time experiment was recorded


Figure S21: Life time experiment and kinetic fit graph of [Ir(ppy-

COOEt)2(dceb)](PF6). Life time experiment was recorded in

nitrogen purged DCM solution at room temperature. 14

Synthesis of 4,4’-Bis(diethylmethylphophonato)-2,2’-bipyridine (dpb) 15

Synthesis of 5-bromo-2,2’-bipyridine (5Brbpy) 15

Synthesis of 2,2':5',2''-terpyridine (bpp) 15

Quantum Yield Measurements and TON calculation 16

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7.58.08.59.09.510.0 ppm

0.97

1.00

2.98

1.97

0.95

11.512.012.513.013.514.014.515.0 ppm

0.848

NCOOH

6

5

4 3 2 3

56

H6(Py)

H3(Ph)H5(Ph)

H2(Ph)H6(Ph)H3(Py)

H4(Py)H5(Py)

OH

Py Ph

Figure S1: 1H NMR (DMSO-d6, 400 MHz) of ppy-COOH.

7.57.67.77.87.98.08.18.28.38.48.58.68.78.8 ppm

1.04

1.06

3.14

2.10

1.00

4.14.24.34.44.54.6 ppm

2.111

1.21.31.41.5 ppm

3.145

NCOOEt

6

5

4 3 2 3

56

H6(Py)

H5(Ph)H3(Ph) H6(Ph)

H2(Ph)H3(Py)

H4(Py)H5(Py)

Ester-CH3Ester-CH2

Py Ph

Figure S2: 1H NMR (DMSO-d6, 400 MHz) of ppy-COOEt.

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Ir

N

N

N

H3CH2COOCCOOCH2CH3

COOCH2CH326

54

3

2

3 5 65

3

3'

6'5'

Ph

Py

(PF6)

9.0 8.5 8.0 7.5 7.0Chemical Shift (ppm)

1.912.014.036.324.012.00

4.8 4.7 4.6 4.5 4.4 4.3 4.2 4.1 4.0 3Chemical Shift (ppm)

4.063.99

1.50 1.45 1.40 1.35 1.30 1.25 1.20Chemical Shift (ppm)

6.226.02

dceb ester CH2 ppy ester CH2dceb ester CH3 ppy ester CH3

H3, H3’(dceb)H5(Ph1)H5(Ph2)

H5(Py1)H5(Py2)

H6, H6’(dceb)H4(Py1)H4(Py2)H2(Ph1)H2(Ph2)

H3(Ph1)H3(Ph2)H6(Py1)H6(Py2)

H5, H5’(dceb)H3(Py1)H3(Py2)

Figure S3: 1H NMR(Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(dceb)](PF6)

9.0 8.5 8.0 7.5 7.0F2 Chemical Shift (ppm)

7.0

7.5

8.0

8.5

9.0

F1

Ch

em

ica

l Sh

ift (

pp

m)

Figure S4: COSY NMR (Acetonitrile-d3, 400 MHz) of [Ir(ppy-COOEt)2(dceb)](PF6)

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29 1.28 1.27 1.26 1.25 1.24 1.23 1.22 1.21 1.20 1.19 1.18 1.17Chemical Shift (ppm)

6.00

1.21

1.23

1.25

IrN

N

N

H3CH2COOC

65

4

3

3'

4'5'6'2

65

4

3

2

3 5Ph

Py

(PF6)

8.5 8.0 7.5 7.0Chemical Shift (ppm)

1.852.022.032.041.992.114.064.062.00

H5(Ph)H2(Ph)

H3(Ph)H3,H3’(bpy)

H4,H4’(bpy)

H3(Py)H5,H5’(bpy)

H5(Py)

H6(Py)H6,H6’(bpy)

H4(Py)


3.99

Ester-CH2

Ester-CH3

Figure S5: 1H NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(bpy)](PF6)

8.5 8.0 7.5 7.0F2 Chemical Shift (ppm)

6.8

6.9

7.0

7.1

7.2

7.3

7.4

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

8.4

8.5

8.6

8.7

F1

Che

mic

al S

hift

(pp

m)

Figure S6: 2D COSY NMR(Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(bpy)](PF6)

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1.901.931.902.001.923.922.172.001.72

4.4 4.3 4.2 4.1 4.0 3.9 3.8 3.7 3.6 3.5 3.4 3.3Chemical Shift (ppm)

4.558.264.61

1.40 1.35 1.30 1.25 1.20 1.15 1.10 1.05 1.00Chemical Shift (ppm)

18.60

H3(dpb)H3’(dpb)

H5(dpb)H5’(dpb)

H5(Py1)H5(Py2)

H5(Ph1)H5(Ph2)

H6(dpb)H6’(dpb)H2(Ph1)H2(Ph2)

H3(Py1)H3(Py2)

H4(Py1)H4(Py2)

H6(Py1)H6(Py2)

H3(Ph1)H3(Ph2)

ppy ester CH2 dpb ester CH2

dpb P-CH2

ppy ester CH3dpb ester CH3

Figure S7: 1H NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(dpb)](PF6)


7.0

7.5

8.0

8.5

9.0

F1

Che

mic

al S

hift

(ppm

)

Figure S8: COSY NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(dpb)](PF6)

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Ir

N

N

N

H3CH2COOC

Br2

65

4

3

2

3 5 6'5'

4'

3'

3

46

Ph

Py

(PF6)


0.950.972.061.033.071.006.393.101.041.041.05


4.15

1.28 1.27 1.26 1.25 1.24 1.23 1.22 1.21 1.20 1.19 1.18Chemical Shift (ppm)

6.40

Ester-CH2 Ester-CH3

H5(Py1)H5(Py2)

H5(Ph1),H5(Ph2)

H5(5Brbpy)

H6(Py2)H3

H3’

H4’H3(Py1)H3(Py2)H4(5Brbpy)

H6’H6(5Brbpy)

H4(Py1)H4(Py2)

H3(Ph1)H3(Ph2)H6(Py1)

H2(Ph1)H2(Ph2)

Ester (1)

Ester (2)

Figure S9: 1H NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(5Brbpy)](PF6)

ppm

6.86.97.07.17.27.37.47.57.67.77.87.98.08.18.28.38.48.58.6 ppm

6.8

7.0

7.2

7.4

7.6

7.8

8.0

8.2

8.4

8.6

Figure S10: COSY NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(5Brbpy)](PF6)

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PR22-2010.220.ESP

4.30 4.25 4.20 4.15 4.10 4.05Chemical Shift (ppm)

4.24

4.16

4.174.17

4.19

4.21

30 1.25 1.20Chemical Shift (ppm)

6.58

1.2

11

.21

1.2

21

.23

1.2

41

.24

IrN

N

N

N

H3CH2COOC

26

54

3

2

3 5 6

5

4

3

3'

4'6'

3''

4''5''

6''

Ph

Py

(PF6)

Ester-CH2

Ester-CH3


H5(Ph1)

H5(Ph2)H3(Ph1)H3(Ph2)

H2(Ph2)H2(Ph1)

H3’ H4’

H6’’ H5’’

H5(Py1)H5(Py2)

H6’

H3(Py1)H3(Py2)H4(bpp)

H6(bpp)

H4(Py1)H4(Py2)

H5(bpp)

H6(Py1)

H4’’H6(Py2)

H3(bpp)

H3’’

-CH3(1)

-CH3(2)

Figure S11: 1H NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(bpp)](PF6) p


6.7

6.8

6.9

7.0

7.1

7.2

7.3

7.4

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

8.4

8.5

8.6

8.7

8.8

8.9

F1

Che

mic

al S

hift

(pp

m)

Figure S12: COSY NMR (Acetonitrile-d6, 400 MHz) of [Ir(ppy-COOEt)2(bpp)](PF6)

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9.0 8.5 8.0 7.5 7.0Chemical Shift (ppm)

H5(Ph1)H5(Ph2)

H5(Py1)H5(Py2)

H3(Py1)H3(Py2)

H2(Ph1)H2(Ph2)

H3(Ph1)H3(Ph2)H6(Py1)H6(Py2)

H4(Py1)H4(Py2)(A)

(B)

(C)

(D)

(E)

Figure S13: Chemical shifts of protons (ppy-COOEt) in different iridium complexes. 1H

NMR(Aceteonitrile-d3, 400 MHz); (A) [Ir(ppy-COOEt)2(dceb)](PF6) ; (B) [Ir(ppy-

COOEt)2(bpy)](PF6) ; (C) [Ir(ppy-COOEt)2(dpb)](PF6)

; (D) [Ir(ppy-

COOEt)2(5Brbpy)](PF6) ; (E) [Ir(ppy-COOEt)2(bpp)](PF6).

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10.0 9.5 9.0 8.5 8.0 7.5 7.0 6.5Chemical Shift (ppm)

H5(Ph1)H5(Ph2)

H5(Ph3)H5(Ph4)

H3(Py3)H3(Py4)

H3(Py1)H3(Py2)

H6(Py3)H6(Py4)

H6(Py1)H6(Py2)

H4(Py1)H4(Py2)

H4(Py3)H4(Py4)

H5(Py1)H5(Py2)

H5(Py1)H5(Py2)

H2(Ph3)H2(Ph4)

H2(Ph1)H2(Ph2)

H3(Ph3)H3(Ph4)

H3(Ph1)H3(Ph2)

SEP17-2010.180.ESP

4.20 4.15 4.10 4.05 4.00 3.95Chemical Shift (ppm)

8.00

4.0

54

.06

4.0

74.0

7

4.0

84

.09

4.1

0

4.1

2

4.1

4

MSO SEP17-2010.180.ESP

1.22 1.21 1.20 1.19 1.18 1.17 1.16 1.15 1.14 1.13 1.12 1.11 1.10 1.Chemical Shift (ppm)

11.37

1.1

4

1.1

4

1.1

61.1

6

1.1

8

1.1

8

Figure S14: 1H NMR (DMSO-d6, 400 MHz) of [Ir(ppy-COOEt)2Cl]2

250 300 350 400 450 500 5500.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Ab

s/n

m

Wavelength/nm

[Ir(ppy-COOEt)2Cl]

2

452413365

Figure S15a: UV-Vis spectra of [Ir(ppy-COOEt)2Cl]2 was recorded in acetonitrile at room

temperature. Concentration of the solution is ~10-5 M.

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250 300 350 400 450 500 5500.0

0.2

0.4

0.6

0.8

1.0

1.2

350 400 450 500 5500.00

0.05

0.10

0.15

0.20

0.25

Ab

sorp

tio

n (

a.u

.)

Wavelength (nm)

1a 1b 1c 1d 1e

Ab

so

rpti

on

(a.

u.)

Wavelength (nm)

Figure S15b: UV-Vis spectra of Iridium complexes, recorded in acetonitrile at room

temperature. Concentration of the solution is ~10-5 M.

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0.000000 0.000002 0.000004 0.000006 0.000008 0.000010-0.05

-0.04

-0.03

-0.02

-0.01

0.00

Vo

lts

Time(sec)

[{Ir(ppy-COOEt)2(Cl)}

2]

Figure S16: Life time experiment and kinetic fit graph of [Ir(ppy-COOEt)2(µ-Cl)]2. Life time

experiment was recorded in nitrogen purged DCM solution at room temperature.

0.0000000 0.0000004 0.0000008 0.0000012 0.0000016 0.0000020-0.05

-0.04

-0.03

-0.02

-0.01

0.00

Vo

lts

Time(sec)

[Ir(ppy-COOEt)2(bpy)](PF

6)

Figure S17: Life time experiment and kinetic fit graph of [Ir(ppy-COOEt)2(bpy)](PF6). Life

time experiment was recorded in nitrogen purged DCM solution at room temperature.

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0.0000000 0.0000004 0.0000008 0.0000012 0.0000016 0.0000020

-0.040

-0.035

-0.030

-0.025

-0.020

-0.015

-0.010

-0.005

0.000

Vol

ts

Time(sec)

[Ir(ppy-COOEt)2(bpp)].PF

6

Figure S18: Life time experiment and kinetic fit graph of [Ir(ppy-COOEt)2(bpp)](PF6). Life


0.0000000 0.0000004 0.0000008 0.0000012 0.0000016 0.0000020-0.05

-0.04

-0.03

-0.02

-0.01

0.00

Vo

lts

time(sec)

[Ir(ppy-COOEt)2(5Brbpy)].PF

6

Figure S19: Life time experiment and kinetic fit graph of [Ir(ppy-COOEt)2(5Brbpy)](PF6).

Life time experiment was recorded in nitrogen purged DCM solution at room temperature.

- 14 -

0.0000000 0.0000004 0.0000008 0.0000012 0.0000016 0.0000020-0.040

-0.035

-0.030

-0.025

-0.020

-0.015

-0.010

-0.005

0.000

Vo

lts

Time(sec)

[Ir(ppy-COOEt)2(dpb)].PF

6

Figure S20: Life time experiment and kinetic fit graph of [Ir(ppy-COOEt)2(dpb)](PF6). Life


0.0000000 0.0000004 0.0000008 0.0000012 0.0000016 0.0000020-0.05

-0.04

-0.03

-0.02

-0.01

0.00

Vo

lts

Time(sec)

[Ir(ppy-COOEt)2(dceb)].PF

6

Figure S21: Life time experiment and kinetic fit graph of [Ir(ppy-COOEt)2(dceb)](PF6). Life


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4,4’-Bis(diethylmethylphophonato)-2,2’-bipyridine (dpb)1

1.7 g (4.97 mmol) of 4,4’-dimethylbromo-2,2-bipyridine in 11.3 cm3 chloroform was refluxed

with 24.17 cm3 of triethylphosphite under a nitrogen atmosphere for 3 hours. Excess

triethylphosphite and chloroform were removed under high vacuum. After the removal of

solvent and excess triethylphosphite, an oily crude product was obtained which was further

washed with pentane and collected as a white solid. Yield: 92% (2.08 g, 4.57 mmol). 1H

NMR (400 MHz, CDCl3) ppm 1.21 (m, 12 H), 3.20 (d, 20 Hz, 4H), 3.96 - 4.06 (m, 8 H),

7.29 (d, J = 5.05, 2 H), 8.31 (s, 2 H), 8.55 (d, J = 5.05 Hz, 2 H) . 31P NMR (400 MHz, CDCl3)

ppm 34.17 ppm.

5-bromo-2,2’-bipyridine (5Brbpy) 2-6

0.299 gm (0.258 mmol) of Pd(PPh3)4 and 2 g (8.44 mmol) of 2,5-dibromobipyridine were

added to a dried two neck round bottom flask under nitrogen atmosphere. The temperature

was kept low using ice bath during the addition of 19.35 ml (8.4 mmol) of 2-pyridylzinc

bromide to the reaction mixture. The reaction mixture was then stirred for 12 hours at room

temperature under nitrogen atmosphere. The reaction mixture was then poured into a

saturated aqueous solution of EDTA/Na2CO3 until some yellow flakes appear. The aqueous

mixture was extracted with dichloromethane and dried over MgSO4. Dichloromethane was

evaporated in air and the crude product was purified by alumina column using hexane/ethyl

acetate (9:1) as eluent. Yield: 1.57 g (6.67 mmol, 79.5%). 1H NMR (400 MHz, DMSO-d6) δ

ppm 7.49 (dd, J = 7.45, 4.80 Hz, 1 H), 7.97 (td, J = 7.71, 7.71 Hz, 1 H), 8.20 (dd, J = 8.46,

2.40 Hz, 1 H), 8.30 - 8.39 (m, 2 H), 8.67 - 8.73 (m, 1 H), 8.82 (d J = 2.40, 1 H)

2,2':5',2''-terpyridine (bpp)7

0.299 g (0.258 mmol) of [Pd(PPh3)4] and 2 g (8.44 mmol) of 2,5-dibromobipyridine were

added to a two necked round bottom flask under a nitrogen atmosphere. 38.7 cm3 (16.8

mmol) of 2-pyridylzincbromide (in THF) was then added to the flask under a nitrogen

atmosphere. The reaction mixture was then stirred for 15 hours in the dark at 200C under

nitrogen atmosphere. Subsequently the reaction mixture was poured into a saturated aqueous

solution of EDTA/Na2CO3. The aqueous solution was extracted with dichloromethane and

the organic layer was dried over MgSO4. The solvent was evaporated in air and the crude

product was purified on a neutral alumina column using hexane/ethyl acetate (9:1) as mobile

phase. Yield: 1.57 g (6.75 mmol, 80%). 1H NMR (400 MHz, DMSO-d6) δ ppm 7.46 (dd, J =

- 16 -

7.58, 4.80 Hz, 1 H), 7.50 (dd, J = 6.69, 5.43, 1.01 Hz, 1 H), 7.98 (d, J = 7.58 Hz, 2H), 8.16 (d,

J = 8.08 Hz, 1 H), 8.47 (d, J = 8.08 Hz, 1 H), 8.52 (d, J = 8.34 Hz, 1 H), 8.63 (d, J = 8.34 Hz,

1 H), 8.70 - 8.78 (m, 2 H), 9.40 (d, J = 2.27 Hz, 1 H). Elemental analysis for C20H14N4: M.W.

= 233.26; Calc. C 77.23, H 4.75, N 18.01, Found. C 77.07, H 4.77 and N 18.25%.

Quantum Yield Measurements:

Following equation was used to calculate the emission quatum yield for all the complexes

both in aerated and deaerated acetonitrile.

Φs = Φr (Is / Ir) . (Ar / As)

Where Φs is the quantum yield of the sample. Φr is the quantum yield of the reference

complex. Is and Ir represent points of maximum intensity. Ar and As represent the

absorbance value of the complex and reference at the excitation wavelength. [Ru(bpy)2]Cl2 is

used as refernce for both aerated ( Փ = 0.02) and deaerated samples in acetonitrile solvent

(Փ = 0.06).8

Experimental conditions for photocatalytic hydrogen: Photocatalytic hydrogen production experiments were carried out using an air-cooling

apparatus for maintaining the solutions at room temperature at 22 ͦ C, during irradiation using

LEDs (355 and 470 nm). Acetonitrile used was dried over calcium hydride and the

triethylamine dried over sodium before being freshly distilled under nitrogen. The samples

were prepared in GC vials (4.9 ml volume, VWR) with a known headspace of 2.9 ml.

Photosensitiser (Iridium complexes) and catalyst K2[PtCl4] were taken in 1:1 ratio and

dissolved in 4:1 Acetonitrile/H2O solution containing 1.2 x 10-4 M of PS. 1.91 ml of the Ir/Pt

solution and 90 µL of 0.5 M triethylamine were added to the GC vials under argon

atmosphere. Subsequently, the GC vials containing 2 ml samples were irradiated with 355

and 470 nm wavelength LED’s for 18 hours. After irradiation, 100 μL samples were drawn

from the headspace and injected into the GC apparatus. The experiments were repeated two

times.

1. I. Gillaizeau-Gauthier, F. Odobel, M. Alebbi, R. Argazzi, E. Costa, C. A. Bignozzi, P.

Qu and G. J. Meyer, Inorg. Chem., 2001, 40, 6073-6079. 2. Q. Liu, H. Duan, X. Luo, Y. Tang, G. Li, R. Huang and A. Lei, Adv. Syn. Cat., 2008,

350, 1349-1354. 3. Y.-Q. Fang and G. S. Hanan, Synlett, 2003, 2003, 0852,0854. 4. A. Lützen and M. Hapke, Eur. J. Org. Chem., 2002, 2002, 2292-2297.

- 17 -

5. J. E. Milne and S. L. Buchwald, J. Am. Chem. Soc., 2004, 126, 13028-13032. 6. U. Kiehne, J. Bunzen, H. Staats and A. Lutzen, Synthesis, 2007, 1061-1069. 7. S. Soman, G. Singh Bindra, A. Paul, R. Groarke, J. C. Manton, F. M. Connaughton,

M. Schulz, D. Dini, C. Long, M. T. Pryce and J. G. Vos, Dalton Trans., 2012, 41, 12678-12680.

8. M. S. Lowry, W. R. Hudson, R. A. Pascal and S. Bernhard, J. Am. Chem. Soc., 2004, 126, 14129-14135.

carboxy derivatised ir(iii) complexes: synthesis ...avishek paul, nivedita das, yvonne halpin,...

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