hydrogenation effects in metalloporphycenes: synthesis and redox behavior … · 2012-03-28 · s-1...

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Supplementary information

Hydrogenation effects in metalloporphycenes: synthesis and redox behavior of

Ni(II)–tetra(n-propyl)dihydroporphycene

Toru Okawara,a Koichi Hashimoto,a Masaaki Abe,*a Hisashi Shimakoshia and Yoshio

Hisaeda*a,b

a Department of Chemistry and Biochemistry, Kyushu University, 744 Moto-oka, Nishi-ku,

Fukuoka 819-0395, Japan.

b International Research Center for Molecular Systems (IRCMS), Kyushu University, 744

Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.

Electronic Supplementary Material (ESI) for Chemical CommunicationsThis journal is © The Royal Society of Chemistry 2012

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Experimental Details

Materials. Reagents and solvents used in this work were of commercially available

reagent-quality unless otherwise stated. Deuterated solvent, CDCl3 (99.7% deuterated) containing

0.03% tetramethylsilane (TMS), used for NMR measurements was purchased from Wako Pure

Chemical Industries, Ltd. and used as received. Dichloromethane and THF used for

electrochemical measurements were distilled from CaH2 before use. Tetra(n-butyl)ammonium

hexafluorophosphate (n-Bu4NPF6) was used as a supporting electrolyte. The free-base

2,7,12,17-tetrapropylporphycene and its nickel(II) complex 3 were prepared according to the

literature methods.1

Instruments. UV/Vis absorption spectra were measured with a Hitachi U-3310

spectrophotometer using CH2Cl2 as a solvent. IR spectra were obtained with a JASCO FT/IR-460

Plus spectrometer with a KBr method. 1H NMR spectra were recorded with a Bruker AVANCE

500 FT-NMR spectrometer. Chemical shifts are reported in ppm with reference to TMS.

Elemental analysis was performed by the Service Center of Elementary Analysis of Organic

Compounds at Kyushu University. Electrochemical measurements were carried out in a

nitrogen-filled glovebox with a standard three-electrode configuration using glassy carbon,

platinum wire and Ag/AgCl as working, counter and reference electrodes, respectively. Under our

experimental conditions, a half-wave potential (E1/2) of ferrocene/ferricinium (Fc/Fc+) redox

couple was observed at +0.60 V and +0.48 V vs. Ag/AgCl, respectively, in THF and CH2Cl2

containing 0.1 M n-Bu4NPF6. EPR spectra were recorded with a Bruker EMX 8/2.7 spectrometer.

X-ray diffraction study. X-ray crystallography was performed using a Bruker SMART APEX

CCD diffractometer quipped with graphite-monochromated Mo Kα radiation (λ = 0.71073 Å)

from a fine-focus sealed tube operated at 50 kV and 30 mA. A single crystal of 1 was mounted on

a glass fiber and the data frames were integrated using SAINT2 and merged to give a unique data


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set for the structure determination. Absorption corrections by SADABS3 were carried out. The

structure was solved by a direct method and refined by the full-matrix least-squares method on all

F2 data using the SHELXL-974 suite of programs. All non-hydrogen atoms were anisotropically

refined. Hydrogen atoms except those on disordered carbon atoms were placed using

geometrically idealized positions and constrained to ride on their parent atoms with Uiso(H) =

1.2Ueq(CH and CH2), Uiso(H) = 1.5Ueq(CH3). Hydrogen atoms on inner nitrogen atoms were

placed with an occupancy of 0.5 and Uiso(H) = 1.2Ueq(N).

Synthesis.

2,3-Dihydro-2,7,12,17-tetrapropylporphycene (1). 2,7,12,17-Tetrapropylporphycene (20.1 mg,

0.0421 mmol) was dissolved in CH2Cl2 (12 mL). To this were added Zn powder (0.273 g, 4.17

mmol) and an aqueous solution of 2 M HCl (12 mL), and the mixture was stirred for 30 min.

After neutralizing with NaHCO3, Zn was removed by filtration. The organic layer was washed

twice with water. After dried over MgSO4, the solvent was removed under reduced pressure. The

remaining solid was dissolved in n-hexane and filtered. Evaporation of the solvent gave 1 as a

purple solid which was recrystallized from ethyl acetate. Yield: 12.9 mg (64%). 1H NMR (500

MHz, CDCl3): δ 9.31 (d, J = 11 Hz, 1H), 8.97 (d, J = 11 Hz, 1H), 8.94 (d, J = 11 Hz, 1H), 8.86 (s,

1H), 8.84 (s, 1H), 8.68 (s, 1H), 8.19 (d, J = 11 Hz, 1H), 5.88 (brs, 1H), 5.00 (dd, J = 9, 17 Hz, 1H),

4.83 (m, 1H), 4.67 (dd, J = 3, 17 Hz, 1H), 3.78 (m, 6H), 3.08 (brs, 1H), 2.42 (m, 1H), 2.28 (m,

6H), 2.10 (m, 1H), 1.70 (m, 1H), 1.56 (m, 1H), 1.27 (m, 9H), 1.06 (t, 3H). 13C{1H} NMR (125

MHz, CDCl3): δ 168.37, 154.41, 143.13, 142.81, 141.27, 140.73, 138.49, 132.68, 132.40, 130.21,

127.30, 122.77, 120.46, 117.30, 114.50, 112.40, 105.72, 105.19, 48.07, 39.95, 38.50, 30.27, 30.04,

29.92, 25.53, 25.22, 25.07, 20.22, 14.53, 14.47, 14.43, 14.28. IR (KBr, cm–1): ν = 2954, 2927,

2869, 1609, 1561, 1496, 1463, 1367, 1257, 1209, 1177, 1083, 1042, 969, 950, 897, 811, 744.

HR-ESI-TOF-MS: Calcd for C32H41N4: m/z = 481.3331 (M+H+). Found: m/z = 481.3365 (M+H+).

UV/Vis (CH2Cl2): λmax/nm (ε/M–1 cm−1): 366 (90,100), 383 (58,300), 402 (102,200), 573 (34,600)


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598 (29,600). Anal. Calcd for C32H40N4: C, 79.96; H, 8.39; N, 11.66%. Found: C, 79.77; H, 8.29;

N, 11.54%.

2,3-Dihydro-2,7,12,17-tetrapropylporphycenatonickel(II) (2). Compound 3 (78.5 mg, 0.148

mmol) was dissolved in CH2Cl2 (50 mL). To this were added Zn powder (3.0 g, 46 mmol) and an

aqueous solution of 2 M HCl (50 mL), and the mixture was stirred for 1 h. After neutralization

with NaHCO3, Zn was removed by filtration. The organic layer was washed twice with water.

After dried over MgSO4, CH2Cl2 was removed under reduced pressure. The resulting violet solid

was dissolved in CH2Cl2/n-hexane (1:3, v/v) and loaded onto a silica gel column (Silica gel 60N,

Kanto Chemicals). Elution with CH2Cl2/n-hexane (1:3, v/v) gave a purple band from which

compound 2 was obtained after recrystallization from CH2Cl2/n-hexane. Yield: 27 mg (35%). 1H

NMR (500 MHz, CDCl3): δ 9.02 (d, J = 11.5 Hz, 1H), 8.62 (d, J = 11.5 Hz, 1H), 8.51 (s, 1H),

8.45 (d, J = 11.5 Hz, 1H), 8.33 (s, 1H), 8.10 (s, 1H), 7.47 (d, J = 11.5 Hz, 1H), 4.33 (m, 1H), 4.22

(dd, J = 9.5, 17.5 Hz, 1H), 4.01 (d, J = 4.0, 17.5 Hz, 1H), 3.74 (t, J = 7.5 Hz, 2H), 3.57 (t, J = 7.5

Hz, 2H), 3.56 (t, J = 7.5 Hz, 2H), 2.22 (m, 2H), 2.15 (m, 4H), 2.08 (m, 1H), 1.86 (m, 1H), 1.47 (m,

1H), 1.36 (m, 1H), 1.25 (m, 9H), 0.94 (t, J = 7.5 Hz, 3H). 13C{1H} NMR (125 MHz, CDCl3): δ

163.35, 156.19, 150.05, 147.43, 147.36, 144.22, 143.16, 141.98, 141.73. 138.70, 136.64, 120.19,

116.42, 115.73, 112.10, 111.14, 103.00, 99.84, 49.77, 39.93, 32.95, 30.88, 30.72, 30.62, 25.36,

24.79, 24.61, 19.40, 14.49, 14.48, 14.45, 14.08. IR (KBr, cm–1): ν = 2956, 2928, 2869, 1642,

1618, 1592, 1555, 1509, 1442, 1375, 1319, 1235, 1142, 1075, 992, 934, 802 cm–1.

HR-ESI-TOF-MS Calcd for C32H38N4Ni: m/z = 536.2450 (M+). Found: m/z = 536.2480 (M+).

UV/Vis (CH2Cl2) λmax/nm (ε/M–1 cm−1): 396 (50,300), 416 (71,300), 564 (24,000), 570 (25,900).

Anal. Calcd for C32H38N4Ni: C, 71.52; H, 7.13; N, 10.43%. Found: C, 71.51; H, 7.19; N, 10.47%.

Figs. S1–S10 show 1D and 2D NMR spectra of 2. Tables S1 and S2 summarize the assignment of

1H and 13C resonances of 1 and 2, respectively. The cyclic voltammograms of 1−3 in THF


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containing n-Bu4NPF6 are shown in Fig. S11−S13.

Chemical reduction of 2 for EPR spectroscopy. In a nitrogen-filled glovebox, compound 2 (0.5

mg, 0.9 µmol) was dissolved in THF (super dehydrated, Wako Pure Chemical Industries, Ltd.) in

an EPR quartz tube. A one equiv. of freshly prepared sodium anthracenide in THF was added to

the solution. The EPR tube was sealed, taken out from the glovebox, and the EPR spectrum,

shown in Fig. S14, was recorded at 125 K.

Controlled potential electrolysis. In a nitrogen-filled glovebox, compound 2 (1.2 mg, 2.1 µmol)

was dissolved in a THF solution (5 mL) containing n-Bu4NPF6 (387 mg, 1.0 mmol) and DDT

(13.6 mg, 42 µmol). A three-electrode cell consisting of a platinum mesh (0.8 × 3 cm) working

electrode, Zn plate (0.5 × 5 cm) counter electrode and an Ag/AgCl reference electrode was used

for the controlled-potential electrolysis. The electrode potential was applied to −2.00 V vs. Fc/Fc+.

After 3-h electrolysis, the solvent was removed by evaporation. The residue was loaded onto a

silica gel column (Silica gel 60N, Kanto Chemicals) and eluted with CH2Cl2/n-hexane (1:6, v/v).

The colorless first band was collected and the solvent was removed. The residual oil was

dissolved in CDCl3. The formation of dechlorinated products, DDD and DDMU, was confirmed

by 1H NMR spectroscopy as shown in Fig. S15.

References:

1) E. Vogel, M. Balci, K. Pramod, P. Koch, J. Lex and O. Ermer, Angew. Chem. Int. Ed. Engl.,

1987, 26, 928.

2) Bruker AXS (2009). SAINT, Bruker AXS Inc., Madison, WI, USA.

3) Bruker AXS (2008). SADABS, Bruker AXS Inc., Madison, WI, USA.

4) G. M. Sheldrick, Acta Cryst. 2008, A64, 112.


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Fig. S1. 1H NMR spectrum of 2 in CDCl3.

Fig. S2. 13C NMR spectrum of 2 in CDCl3.


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Fig. S3. 1H-1H COSY spectrum of 2 in CDCl3 from 0 to 5 ppm.

Fig. S4. 1H-1H COSY spectrum of 2 in CDCl3 from 3 to 9 ppm.


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Fig. S5. HMQC spectrum of 2 in CDCl3 from 0.5 to 5 ppm (1H) and from 10 to 50 ppm (13C).

Fig. S6. HMQC spectrum of 2 in CDCl3 from 6.5 to 9 ppm (1H) and from 100 to 125 ppm (13C).


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Fig. S7. HMBC spectrum of 2 in CDCl3 from 0.5 to 9 ppm (1H) and from 10 to 60 ppm (13C).

Fig. S8. HMBC spectrum of 2 in CDCl3 from 1 to 9.5 ppm (1H) and from 90 to 180 ppm (13C).


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Fig. S9. HMBC spectrum of 2 in CDCl3 from 6 to 10 ppm (1H) and from 16 to 160 ppm (13C).

Fig. S10. HMBC spectrum of 2 in CDCl3 from 0 to 5 ppm (1H) and from 10 to 160 ppm (13C).


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Fig. S11. Cyclic voltammogram of 1 in THF containing 0.1 M n-Bu4NPF6.



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Fig. S14. An EPR spectrum of 2− in frozen THF at 125 K. The sample was prepared by reducing 2

with 1 equiv. of sodium anthracenide.


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Fig. S15. A 1H NMR spectrum of reaction products in CDCl3 obtained after electrolysis of DDT in

the presence of 2 (Eap = −2.0 V vs. Fc/Fc+).


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Table S1. Assignments of the peaks in 1H and 13C NMR spectra for 1.


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Table S2. Assignments of the peaks in 1H and 13C NMR spectra for 2.


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