Photoinduced electron transfer in Zn(II)porphyrin-bridge-Pt(II)acetylide Complexes: Variation in rate with anchoring group and position of the bridge

Article abstract of DOI:10.1021/ic100605t

The synthesis and photophysical characterization of two sets of zinc porphyrin platinum acetylide complexes are reported. The two sets of molecules differ in the way the bridging phenyl-ethynyl unit is attached to the porphyrin ring. One set is attached v

Full text of DOI:10.1021/ic100605t

Supporting information
for
Photoinduced Electron Transfer in Zn(II)porphyrin-Bridge-
Pt(II)acetylide complexes: Variation in Rate with Anchoring Group
and Position of the Bridge
Erik Göransson,1 Julien Boixel,2 Cyrille Monnereau,2 Errol Blart,2 Yann Pellegrin,2 Hans-Christian
Becker,1,3 Leif Hammarström1* and Fabrice Odobel2*
1Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20
Uppsala, Sweden.
2CEISAM, Chimie Et Interdisciplinarité, Synthèse, Analyse, Modélisation CNRS, UMR CNRS
6230, UFR des Sciences et des Techniques 2, rue de la Houssinière - BP 92208, 44322 NANTES
Cedex 3, France.
3Present address: Department of Chemical and Biological Engineering, Chalmers University of
Technology, SE-412 96 Gothenburg, Sweden
*To whom correspondence should be addressed. E-mail: Leif.Hammarstrom@fotomol.uu.se,
Fabrice.Odobel@univ-nantes.fr
Content
Key to labels in 1H-NMR data, reported in the experimental section
Synthesis and characterisation of compound 3, 4, 7, 8, 11 and 15
Comparison between absorption spectra of donor-acceptor dyads and references
Absorption and emission properties in 2-MTHF
Emission spectra in DMF
2
3
6
6
7
Additional fs-TA pump probe data
8
Reactions from the porphyrin S2-state
9
State diagram for electron transfer reaction in charge-shift compounds
References
10
10
1

Key to labels in 1H-NMR data, reported in the experimental section
PF6
Ar
N
PF6
Hβ
Hβ
N
N
Ph
Zn
Ph
Hβ
N
Pt
HTpy
N
N
N
N
Hβ
Zn
Ar
Pt
N
Hmeso
N
HTpy
N
N
N
N
HΦ
HΦ
HTpy
Ph
Ph
ZnP-m- -Pt+
ZnP- -Pt+
HTpy
Hβ
Hβ
O
EtO2C
O
O
H2C CH3
HBpy
EtO2C
O
H2C CH3
HBpy
N
N
Pt
N
N
Pt
HΦ
Hβ
HΦ
Hβ
Ph
Ph
Ph
Ph
Ph
Ar
Ph
Ar
N
N
N
Zn
N
N
Zn
N
N
N
Zn
Zn
N
N
N
Hβ
N
N
N
Hβ
N
N
Ar
Ar
Ph
Hmeso
Ph
Hβ
(ZnP-m- ) -Pt
(ZnP- ) -Pt
Chart S1. Structures of ZnP-m-φ-Pt+, ZnP-β-Pt+, (ZnP-m-φ)2-Pt and (ZnP-β)2-Pt. The proton labels correspond to
those reported in the experimental setup in the manuscript.
2

Synthesis and characterisation of compound 3, 4, 7, 8, 11 and 15
1-(4-triisopropylacetylene)benzene)-5,15-(3,5-di-tert-butylphenyl)-zincporphyrin (3)
Ar
Hβ
N
N
N
N
Zn
TIPS
Hmeso
HΦ
Ar
4-(pinacolboron)-(triisopropylacetylene)benzene 1 (185 mg, 0.44 mmol), the bromo zinc porphyrin 2
(342 mg, 0.44 mmol), triphenylphosphine (133 mg, 0.51 mmol), barium hydroxyde hexahydrate
(219 mg, 0.66 mmol) and palladium Pd2dba3.CHCl3 (68 mg, 7.10-5 mol) were dissolved in a mixture
of DME (28 mL) and H2O (1.8 mL) and degassed by three freeze-pump-thaw cycles. The reaction
mixture was stirred under argon for 12 hours at 90°C and purified by flash chromatography on silica
gel using petroleum ether/CH2Cl2: 6/4 as eluent to give the expected product (85 mg, 20%) as a
purple solid. 1H NMR δ: (300 MHz, CDCl3, 25°C): 10.29 (s, 1H; Hmeso); 9.44 (d, 3J= 3.9Hz, 2H, Hβ);
3
3
3
9.19 (d, J= 3.9Hz, 2H, Hβ); 9.10 (d, J= 3.9Hz, 2H, Hβ); 8.99 (d, J= 3.9Hz, 2H, Hβ); 8.22 (m, 2H,
Hφ); 8.15 (s, 4H, HAr); 7.5 (m, 4H, 2Hφ+2HAr); 1.60 (s, 36H, tBu); 1.20 (s, 21H, TIPS). HR-ESMS:
calcd for C65H76N4SiZn: 1004.5125; found 1004.5114 [M+].
1-(4-acetylene)benzene)-5,15-(3,5-di-tert-butylphenyl)-zincporphyrin (4)
Ar
Hβ
Hβ
N
N
N
N
Zn
Halkyne
Hmeso
HΦ
Ar
The porphyrin 3 (85 mg, 0.1 mmol) was dissolved in THF (13 mL) and stirred with TBAF (110 μL,
0.12 mmol) at r.t. for 1h. The mixture was washed with water and dried over Na2SO4 to afford a
purple solid (80 mg, 95%). 1H NMR δ: (300 MHz, CDCl3, 25°C): 10.29 (s, 1H; Hmeso); 9.45 (d, 3J=
3
3
3
3.9Hz, 2H, Hβ); 9.195 (d, J= 3.9Hz, 2H, Hβ); 9.09 (d, J= 3.9Hz, 2H, Hβ); 9.00 (d, J= 3.9Hz, 2H,
Hβ); 8.225 (m, 2H, Hφ); 8.147 (s, 4H, HAr); 7.5 (m, 4H, 2Hφ+2HAr); 3.30 (s, 1H, Halkyne), 1.60 (s,
36H, tBu). UV-vis (CH2HCl2): λ/nm (ε/104 M-1cm-1): 305 (1.3), 351 (0.91), 395 (2.2), 414 (22), 450
(0.63), 545 (1.1), 584 (0.27). HR-ESMS: calcd for C56H56N4Zn: 848.3791; found 848.3802 [M+].
3

3-(4-triisopropylsilylacetylene)benzene)-1,5,15,20-phenyl-porphrin (7)
Ph
Zn
Ph
Hβ
TIPS
Hβ
N
N
N
N
HΦ
Ph
Ph
Hβ
Hβ
The β bromo porphyrin 6 (108 mg, 1.6.10-4 mol) and 4-(tris(isopropyl)silylethynyl)-ethynyl benzene
5 (180 mg, 6.2.10-4 mol) were dissolved in a mixture of THF (35 mL) and triethylamine (3 mL). The
resulting solution was purged with argon through 3 freeze-pump-thaw cycles and tetra-
(triphenylphosphine)-palladium (33 mg, 3.2.10-5 mol) and triphenyl arsine (161 mg, 5.3.10-4 mol)
were added. A second cycle of 3 freeze-pump-thaw cycles was performed before heating at 60°C
overnight. The solvents were removed and the crude product was purified by column
chromatography over silica gel (petroleum ether/CH2Cl2: 6/4), to afford 7 as a green solid (65 mg, 45
%). 1H NMR δ: (300 MHz, CDCl3, 25°C): 9.17 (s, 1H, Hβ); 8.90 (s, 1H, Hβ); 8.88 (s, 1H, Hβ); 8.85
3
3
(d, J= 4.8Hz, 2H, Hβ); 8.76 (d, J= 4.6Hz, 2H, Hβ); 8.20 (m, 8H, HPh); 7.5-7.8 (m, 12H, HPh); 7.46
(d, 3J= 8.0Hz, 2H, Hφ); 7.33 (d, 3J= 8.0Hz, 2H, Hφ); 1.21 (s, 21H, HTIPS). UV-vis (CH2HCl2): λ/nm
(ε/104 M-1cm-1): 288 (1.8), 353 (1.1), 432 (20), 560, (1.3), 595 (0.55). HR-ESMS: calcd for
C63H52N4SiZn: 956.3253; found 956.3259 [M+].
3-(4-acetylene)benzene)-1,5,15,20-phenyl-zincporphrin (8)
Ph
Zn
Ph
Hβ
HAlkyne
Hβ
N
N
N
N
HΦ
Ph
Ph
Hβ
Hβ
The porphyrin 7 (89 mg, 0.1 mmol) was dissolved in THF (13 mL) and stirred with TBAF (120 μL,
0.12 mmol) at r.t. for 1h. The mixture was washed with water and dry over Na2SO4 to afford the
1
green solid (83 mg, 100%). H NMR δ: (300 MHz, CDCl3, 25°C): 9.22 (s, 1H, Hβ); 8.905 (s, 1H,
3
3
Hβ); 8.89 (s, 1H, Hβ); 8.86 (d, J= 4.8Hz, 2H, Hβ); 8.76 (d, J= 4.8Hz, 2H, Hβ); 8.20 (m, 8H, HPh);
3
3
7.6 – 7.8 (m, 12H, HPh); 7.48 (d, J= 8.1Hz, 2H, Hφ); 7.34 (d, J= 8.1Hz, 2H, Hφ); 3.19 (s, 1H,
alkyne). UV-vis (CH2HCl2): λ/nm (ε/104 M-1cm-1): 287 (1.83), 352 (1.06), 432 (19.8), 559 (1.3), 595
H
(0.54). HR-ESMS: calcd for C54H32N4Zn 800.1918, found: 801.1997 [MH+]. E.A: calcd for C:
60.42, H: 6.59, N: 1.70, found C: 60.47, H: 6.52, N: 1.86.
4

General Procedure for the preparation of the reference platinum complexes 11 and 15.
The platinum complex 9 or 14 (typically 0.01 mmol) and phenylacetylene (7 or 14 eq., 0.07 or 0.14
mmol respectively) were dissolved in distilled dichloromethane (80 mL). Diisopropylamine (1 mL)
was added. The mixture was degassed by N2 bubbling with sonication, and a catalytic amount of
copper iodide (1 mg) was added. The mixture was then stirred in the dark for 10 hours, and water
was added. The precipitate was isolated by filtration as an orange solid.
11: yield 63%.
PF6
N
Pt
N
HTpy
HΦ
N
HTpy
3
1H NMR δ: (300 MHz, d6-DMSO, 25°C): 9.15 (m, 1H, Htpy); 8.65 (m, 6H, Htpy); 8.5 (t, J= 8.0Hz,
3
3
3
2H, Htpy); 7.93 (t, J= 6.9Hz, 2H, Htpy); 7.50 (d, J= 7.2Hz, 2H, Hφ); 7.35 (d, J= 7.5Hz, 2H, Hφ);
3
7.30 (d, J= 6.9Hz, 1H, Hφ). UV-vis (DMF): λ/nm (ε/104 M-1cm-1): 262 (0.27), 317 (0.10), 350
(0.09), 420 (0.06). HR-ESMS: calcd for C23H16N3Pt: 528.0972, found 528.0973 [M+]. E.A.: calcd
for C 6.25, H 0.23, N 0.97, found C 6.22, H 0.10, N 0.95.
15: yield 99%.
O
EtO2C
O
H2C CH3
HBpy
N
N
Pt
HΦ
1H NMR δ: (300 MHz, CDCl3, 25°C): 9.70 (m, 2H, Hbpy); 8.62 (s, 2H, Hbpy); 8.05 (d, 3J= 4.
2Hz, 2H, Hbpy); 7.48 (m, 4H, Hφ); 7.16 – 7.35 (m, 6H, Hφ); 4.45 (q, 4H, HCH2); 1.5 (t, 6H, HCH3).
UV-vis (DMF): λ/nm (ε/104 M-1cm-1): 239 (0.16), 264 (0.22), 313 (0.13) 441 (0.05). HR-ESMS:
calcd for C32H26N2O4Pt, Na+ 719.1418; found 719.1417 [M+]. E.A.: calcd for C 54.15, H 4.45, N
3.13, found C 54.34, H 4.33, N 3.76.
5

Comparison between absorption spectra of donor-acceptor dyads and
references
Figure S1. Comparison of the absorption spectra of ZnP-m-φ-Pt+ and ZnP-β-Pt+ and their respective components. a)
Absorption spectra of ZnP-m-φ-Pt+ (blue) and its components; ZnP-m-φ (red) and Pt(tpy)(eφ)+ (green). b) ZnP-β-Pt+
(blue) and its to components; ZnP-β (red) and Pt(tpy)(eφ)+ (green).
Absorption and emission properties in 2-MTHF
Table S1. Absorption and emission properties in 2-MTHF.
a
λabs
(nm)
λem (RT)a λem (77 K)b
E00
Relative
τem (fraction)
(nm)
670
620
(nm)
591
593
-
(eV)
2.09c
2.08c
2.07d
Φem
(ns)
-
-
450
455
303, 403, 424,
556, 595
420, 551, 591
435, 564, 600
-
-
-
Pt(bpy)(eφ)2
Pt(tpy)(eφ)+
ZnTTP
604, 656
1.9 (0.96)
597, 647
616, 668
770
810
2.09d
2.04d
1e
1f
2.4 (0.91)
1.8 (0.95)
ZnP-m-φ
ZnP-β
ZnP-m-φ-Pt+
(ZnP-m-φ)2-Pt
ZnP-β-Pt
-
-
-
313, 436, 566,
601
319, 434, 564,
616, 669
616, 669
-
2.04d
2.04d
-
0.30f
0.06f
-
0.09 (0.62)
(ZnP-β)2-Pt
-
-
599
-
ZnP-m-e-Pt+ g
-
a) Peak position, b) Only phosphorescence peaks reported, c) From 77 K emission peak, d) From ((λabs)-1+(λemi, RT) -1))/2,
e) Using ZnP-m-φ as reference, f) Using ZnP-β as reference, g) Data not given for 2-MTHF in Monnereau et al..1
6

Figure S2. Comparison of absorption (full line) and emission (doted line) spectra of ZnP-β-Pt+ in DMF (red) and 2-
MTHF (blue).
Emission spectra in DMF
Figure S3. Emission spectra of ZnP-m-φ (blue), ZnP-β (red) and ZnTTP (gray) in DMF.
7

Additional fs-TA pump probe data
Figure S4. Transient spectra of a) ZnP-m-φ (λexc = 596 nm) and b) ZnP-β (λexc = 603 nm) in DMF. The Spectra are at 1
ps (purple), 10 ps (blue), 100 ps (orange), 1000 ps (red) and 6000 ps (brown).
Figure S5. The figure show fs-TA measurements on (ZnP-β)2-Pt in a) DMF (λexc 605 nm) and b) 2-MTHF (λexc 602
nm). The difference spectra represents times at 1 ps (purple), 10 ps (blue), 100 ps (orange) and 1000 ps (red). In 2-
MTHF there is almost quantitative yield of the triplet state (τ = 26 ps). In DMF the singlet state spectra decays slower
and seems to mainly go back to the ground state (τ = 61 ps). There is some triplet state formed, but the yield is only
about a third of that in 2-MTHF.
8

Reactions from the porphyrin S2-state
Figure S6 shows fs-TA measurements on ZnP-m-φ and ZnP-m-φ-Pt+ in 2-MTHF, after excitation of
porphyrin S2 state at 420 nm. The S2-state in ZnP-m-φ undergo internal conversion to the S1-state
with τ = 1.7 ps. For ZnP-m-φ-Pt+ the quenching of the S2 signal is significantly faster (τ = 0.35 ps).
This rapid process yield the S1-state which reacts in the same way as an initial S1 excitation (Figure
3); i.e. electron transfer with τ = 24 ps and recombination with τ = 5 ps.
Figure S6. fs-TA measurements on ZnP-m-φ (a, b) and ZnP-m-φ-Pt+ (c, d) in 2-MTHF exciting into the porphyrin S2-
state at 420 nm. a) Difference spectra of ZnP-m-φ taken 0.2 ps (purple), 1 ps (blue), 10 ps (green) and 200 ps (red) after
excitation. b) Kinetic traces of ZnP-m-φ at 395 nm and 455 nm. c) Difference spectra of ZnP-m-φ-Pt+ taken 0.2 ps
(purple), 1 ps (blue), 10 ps (green) and 200 ps (red) after excitation. d) Kinetic traces of ZnP-m-φ-Pt+ at 395 nm and 455
nm.
9

State diagram for electron transfer reaction in charge-shift compounds
Figure S7. A generic state diagram for a charge-shift reaction, showing how the relative positioning of the states change
with solvent polarity. a) Electron transfer from an excited state resulting in a charge-shifted state (CShS). b) Back
electron transfer from a charge shifted state to either a low lying triplet state (T1) or to the ground state (S0). Notice how
the shift to a less polar solvent results in decrease in activation energy BET to T1, while the barrier for BET to S0 is
increased.
References
(1)
Monnereau, C.; Gomez, J.; Blart, E.; Odobel, F.; Wallin, S.; Fallberg, A.;
Hammarström, L. Inorg. Chem. 2005, 44, 4806-4817.
10