Photoinduced Electron Transfer
FULL PAPER
[AlACHTUNGTERNU(NNG DPP)ACHUTNGTERNNUG(AqCOO)]: [AlACHTUNREGTG(NNUN DPP)CAHTNUGTREN(NUNG OMe)] (150 mg, 0.12 mmol) was dis-
photoinduced electron transfer and the back electron trans-
fer adiabatic: the electron-transfer rate is determined solely
by the driving force and reorganization energy of electron
transfer, and not by geometric differences between the
donor and acceptor moieties. Thus, the present study pro-
vides valuable insights for the rational design of efficient
electron-transfer systems of metalloporphyrins.
solved in CH2Cl2/acetone (3:1 v/v) with an aqueous solution of K2CO3
(5 mm, 1 mL), and the mixture was heated under reflux overnight. The
solvent was evaporated, and the crude product was dissolved in CH2Cl2.
After filtration, the filtrate was washed with water in a separating funnel
and then dried over anhydrous sodium sulfate. Evaporation of the sol-
vent gave a solid of [Al
using the same procedure as for [Al
(DPP)(OH)] instead of [Al(TPP)(OMe)]. Recrystallization of the solid
A
R
ACHTUNGTREN(NUNG AqCOO)] was prepared
A
ACHTUNGTRENNUNG
A
R
ACHTUNGTRENNUNG
from CH2Cl2/hexane gave purple crystals, which were used for the ele-
mental analysis. Then, the crystals were redissolved in PhCN, and the ad-
dition of hexane afforded plate-shaped crystals suitable for X-ray crystal-
lographic analysis. Yield: 71% (126.2 mg). Elemental analysis calcd (%)
for C107H67O4N4Al·C6H14: C 85.58, H 5.15, N 3.53; found: C 85.21, H 5.00,
N 3.57; 1H NMR (CDCl3): d=8.23–8.18 (m, 2H; Aq5-, Aq8-H), 7.78–
7.73 (m, 3H; Aq1-, Aq6-, Aq7-H), 7.05 (d, J=8.1 Hz, 1H; Aq4-H), 7.03
(d, J=6.9 Hz, 8H; meso-phenyl o-H), 6.74–6.63 (m, 48H; meso-phenyl p-
H, b-phenyl H), 6.45 (d, J=8.1 Hz, 1H; Aq3-H), 6.47–6.42 ppm (m, 8H;
meso-phenyl m-H); MALDI-TOF MS (matrix: dithranol): m/z calcd for
C107H67O4N4Al [M]+: 1499.7; found: 1500.1; UV/Vis (in PhCN): lmax (e)=
455 (3.6ꢀ105), 585 (1.7ꢀ104), 634 nm (1.5ꢀ104 mꢀ1 cmꢀ1).
Experimental Section
Materials: Chemicals were purchased from commercial sources and used
without further purification, unless otherwise noted. 2,3,5,6-Tetramethyl-
p-benzoquinone (Me4Q), 2,5-dimethyl-p-benzoquinone (Me2Q), 2-
methyl-p-benzoquinone (MeQ), p-benzoquinone (Q), 2-chloro-p-benzo-
quinone (ClQ), 2,5-dichloro-p-benzoquinone (Cl2Q), and p-chloranil (tet-
rachloro-p-benzoquinone; Cl4Q), supplied by Aldrich, were purified by
vacuum sublimation. Benzonitrile (PhCN) was purchased from Wako
Pure Chemical Industries, Ltd. and purified by successive distillation over
P2O5. CH2Cl2, used as a solvent, was distilled over CaH2 before use.
H2TPP was purchased from a commercial source and used without fur-
ther purification. H2DPP was synthesized as reported previously.[44, 45]
X-ray crystallographic measurements:
A single crystal of [AlACHTUNGTRENNUNG(TPP)-
A
ACHTUNGTRENNUNG
mounted in a loop with liquid paraffin. The measurements were per-
formed on a Rigaku Mercury CCD area detector at ꢀ1508C with graph-
ite-monochromated MoKa radiation (l=0.71070 ꢂ) up to 2qmax =54.78.
All calculations were performed using the Crystal Structure crystallo-
graphic software package,[49] and structure refinements were made by a
direct method using SIR97.[50] The crystallographic data are summarized
in Table 3. The Flack parameter was obtained as 0.1(2) by using 3442
Friedel pairs to confirm the absolute structure crystallographically.[51]
Synthesis of porphyrin complexes: [Al
and [Zn
(DPP)][48] were synthesized on the basis of the procedure report-
ed previously.
[Al(DPP)(PhCOO)]: Triethylaluminum (1.2 equiv, 0.15 mL, 1.9m in tolu-
ene) was added to solution of dodecaphenylporphyrin (H2DPP)
ACHTUNGTRENU(NGN TPP)ACHNUTRTGENNUNG ACTHNUGTRENNUGN
(PhCOO)],[46] [Zn(TPP)],[47]
ACHTUNGTRENNUNG
G
ACHTUNGTRENNUNG
a
(350 mg, 0.29 mmol) in dry CH2Cl2 (300 mL) under an atmosphere of N2.
The solution was stirred at room temperature for 4 h. The reaction was
quenched with 5 mL of methanol, and the stirring was continued over-
night. The solvent was removed with a rotary evaporator. The residue
was purified by column chromatography on activated alumina using
CH2Cl2 as eluent. H2DPP can be removed as the first fraction, and [Al-
Table 3. X-ray
crystallographic
data
for
[AlACTHNGUTERNNU(G TPP)ACHTUNGTRENNUNG(AqCOO)-
A
E
N
(H2O)]·PhCN.
[Al(TPP)(AqCOO)-
G
E
[Al
ACHUTGTNREN(NUG DPP)ACHTUNGTRENNUNG(AqCOO)-
ACHTUNGTRENNUNG(DPP)ACHTUNGTRENNUNG(OMe)] trapped at the top of the column was collected by using
A
ACHTUNGTRENNUNG
CH2Cl2/MeOH as the eluent. The solution was evaporated to dryness to
obtain a purple solid (296 mg, 81% yield). Solid benzoic acid (5 equiv,
formula
fw
crystal system
space group
T [K]
a [ꢂ]
b [ꢂ]
c [ꢂ]
a [8]
b [8]
C66H40AlN5O5
1010.05
tetragonal
P41
123
13.1233(11)
13.1233(11)
28.758(3)
C114H74AlN5O5
1620.76
47.6 mg, 0.39 mmol) was added to
a solution of [AlACHTUNGTREGUN(NN DPP)ACHTGNURTEN(NUGN OMe)]
triclinic
(100 mg, 0.078 mmol) in CHCl3 (50 mL). The resulting solution was
stirred at room temperature for 24 h and then filtered to remove the
excess benzoic acid. Hexane was added to the solution, yielding [Al-
¯
P1
298
13.4830(2)
16.3174(3)
20.1155(4)
90.1790(10)
91.8430(10)
106.7710(10)
4234.77(13)
2
ACHTUNGTRENNUNG(DPP)ACHTUNGTRENNUNG(PhCOO)] as a purple solid. Yield: 91% (97 mg). Elemental analy-
sis calcd (%) for C99H65O2N4Al·C6H14: C 86.63, H 5.47, N 3.85; found: C
86.50, H 5.32, N, 3.91; 1H NMR (CDCl3): d=7.07 (d, J=7.3 Hz, 1H;
axial phenyl p-H), 7.01 (d, J=7.2 Hz, 8H; meso-phenyl o-H), 6.82 (t, J=
7.7 Hz, 2H; axial phenyl m-H), 6.75–6.41 (m, 52H; meso-phenyl m-, p-H,
b-phenyl H), 5.99 ppm (d, J=7.1 Hz, 2H; axial phenyl o-H); MALDI-
TOF MS (matrix: dithranol): m/z calcd for C99H65O2N4Al [M]+: 1368.5;
found: 1368.5; UV/Vis (in PhCN): lmax (e)=455 (3.6ꢀ105), 585 (1.7ꢀ
104), 634 nm (1.5ꢀ104 mꢀ1 cmꢀ1).
90
90
90
g [8]
V [ꢂ3]
Z
4952.7(7)
4
0.0478 [I>2.0s(I)]
0.0993 [I>2.0s(I)]
0.824
[a]
R1
0.0656 [I>2.0s(I)]
0.1605 [I>2.0s(I)]
1.049
[b]
Rw
[Al
ACHTUNGTRENNUNG(TPP)ACHTUNGTRENNUNG
GOF
Flack parameter
(8 equiv, 400 mg, 1.60 mmol) was added to a solution of [Al
N
ACHTUNGTRENNUNG
0.1(2)
–
(137 mg, 0.21 mmol) in CHCl3 (250 mL). The solution was stirred at
room temperature for 12 h and then filtered to remove the excess
AqCOOH. The solvent was removed with a rotary evaporator, yielding
[a] R1=Sj jFo jꢀjFc j j/SjFo j. [b] Rw =[S(w(F2oꢀFc2)2)/Sw(Fo2)2]1/2
. w=1/
[s2(Fo2)+(0.0500P)2 +30.0000P, in which P=(max(Fo2,0)+2F2c)/3.
[AlACHTUNGTRENNUNG(TPP)ACHTUNGTRENNUNG(AqCOO)] as a purple solid. Recrystallization of the solid from
PhCN/hexane gave purple crystals, which were dried in vacuo at 1008C
for 12 h. Yield: 90% (171 mg). Elemental analysis calcd (%) for
C59H35O4N4Al·H2O·0.5PhCN: C 78.16, H 4.14, N 6.56; found: C 78.07, H
The diffraction data of [AlCAHTUNGTREN(NNGU DPP)ACHTUNGTREG(NNUN AqCOO)CAHTNUGTREN(UNNG H2O)]·PhCN were collected
at ambient temperature from a small dark violet plate (0.10ꢀ0.07ꢀ
0.03 mm3), which was obtained from the crystallization solution (PhCN/
hexane), immediately covered with a thin layer of Paratone-N oil and
fixed to a glass rod with epoxy resign. Unlike the unprotected samples,
which suffered from loss of solvent in less than 0.5 h, the protected crys-
tal did not show any signs of degradation during data collection, and
therefore no decay correction was applied. The X-ray diffraction data, up
to 2q=528, were collected by w-scans (0.58 frame width) with an APEX2
diffractometer (Bruker AXS),[52] using MoKa X-rays obtained from a ro-
1
4.22, N 6.47; H NMR (CDCl3): d=9.09 (s, 8H; b-phenyl H), 8.18 (d, J=
5.7 Hz, 8H; meso-phenyl o-H), 8.05 (m, 2H; Aq5-, Aq8-H), 7.78–7.72
(m, 12H; meso-phenyl m-, p-H), 7.63 (m, 2H; Aq6-, Aq7-H), 7.34 (d, J=
8.1 Hz, 1H; Aq4-H), 6.14 (s, 1H; Aq1-H), 5.43 ppm (d, J=8.1 Hz, 1H;
Aq3-H); MALDI-TOF MS (matrix: dithranol): m/z calcd for
C59H35O4N4Al [M]+requires 890.9; found: 890.1; UV/Vis (in PhCN): lmax
(e)=: 320 (1.8ꢀ104), 426 (3.9ꢀ105), 561 (1.4ꢀ104), 601 nm (6.0ꢀ
103 mꢀ1 cmꢀ1).
Chem. Eur. J. 2011, 17, 12372 – 12384
ꢁ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
12381