Effects of meso -diarylamino group of porphyrins on optical and electrochemical properties

Article abstract of DOI:10.1142/S1088424619500652

Introduction of an electron-donating meso-diarylamino group into a porphyrin core affords its broadened and red-shifted absorption and raises the HOMO level of the porphyrin. In this regard, porphyrins with multiple meso-diarylamino groups are expected to

Full text of DOI:10.1142/S1088424619500652

Journal of Porphyrins and Phthalocyanines
J. Porphyrins Phthalocyanines 2019; 23: 1–8
DOI: 10.1142/S1088424619500652
Published at http://www.worldscinet.com/jpp/
Effects of meso-diarylamino group of porphyrins on optical
and electrochemical properties
Tomohiro Higashinoa◊, Yamato Fujimoria, Issei Nishimuraa and Hiroshi Imahori*a,b◊
aDepartment of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku,
Kyoto 615-8510, Japan
bInstitute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
Dedicated to Professor Atsuhiro Osuka on the occasion of his 65th birthday.
Received 10 April 2019
Accepted 14 May 2019
ABSTRACT: Introduction of an electron-donating meso-diarylamino group into a porphyrin core
affords its broadened and red-shifted absorption and raises the HOMO level of the porphyrin. In this
regard, porphyrins with multiple meso-diarylamino groups are expected to show unique optical and
electrochemcial properties depending on the number of the meso-diarylamino groups. Herein, we report
a series of porphyrins with a different number of the meso-diarylamino groups. They were prepared by
the iodine(III)-mediated oxidative amination reaction of the corresponding meso-free porphyrins. With
increasing the number of the meso-diarylamino groups, both red shifts and broadening in the absorption
and negative shifts in the oxidation potential were observed. Notably, the oxidation potential of the
porphyrin with four meso-diarylamino groups is comparable to that of tetrathiafulvalene, which is one
of representative electron donors, suggesting the potential utility of multiply meso-aminated porphyrins
as hole-transporting materials and as electron donors forming charge-transfer complexes with electron
acceptors. We believe that this study sheds light on porphyrins with multiple electron-donating groups
as organic functional materials.
KEYWORDS: porphyrin, amination, electron-donating substituent.
meso-diarylamino group into a porphyrin core affords
INTRODUCTION
its broadened and red-shifted absorption and raises the
Electron-donating triarylamines and diarylamines
HOMO level of the porphyrin. In addition, porphyrins
have attracted significant interest from chemists because
with two meso-diarylamino groups display larger
they have been used as important building blocks for
broadening and red shifts in the absorption and rise
organic functional materials in organic light-emitting
in the HOMO level than porphyrins with one meso-
diodes (OLEDs) [1–5] and organic solar cells (OSCs)
diarylamino group. In this regard, porphyrin dyes
[6–11]. In particular, meso-aminoporphyrins have
with multiple meso-diarylamino groups are expected
drawn increasing attention owing to their great potential
to show unique optical and electrochemcial properties
as excellent sensitizers for dye-sensitized solar cells
depending on the number of the meso-diarylamino
(DSSCs) [12–21]. We previously reported the influences
groups. Herein, we report the synthesis and optical and
of the number and position of meso-diarylamino groups
on the optical, electrochemical, and photovoltaic
properties [22, 23]. Introduction of an electron-donating
electrochemical properties of porphyrins with multiple
meso-diarylamino groups N1P–N4P in comparison with
5,10,15,20-tetraphenylporphyrin (TPP) as a reference
(Fig. 1). We found that both red shifts and broadening
in the absorption and negative shifts in the oxidation
◊SPP full member in good standing
potential are enhanced with an increase in the number of
the meso-diarylamino groups.
*Correspondence to: Hiroshi Imahori, email imahori@scl.
kyoto-u.ac.jp.
Copyright © 2019 World Scientific Publishing Company

2
T. HIGASHINO ET AL.
Ph
Ph
Ph
Ph
Ph
NAr2
NH
N
N
NH
N
N
NH
N
N
NH
N
N
NH
N
N
NH
N
N
Ph
Ph Ph
NAr2 Ph
NAr2 Ar2N
NAr2 Ar2N
NAr2 Ar2N
NAr2
HN
HN
HN
HN
HN
HN
Ph
TPP
Ph
N1P
NAr2
Ph
trans-N2P
NAr2
NAr2
cis-N2P
N3P
N4P
Fig. 1. Molecular structures of meso-diarylaminoporphyrins N1P–N4P and a reference 5,10,15,20-tetraphenylporphyrin TPP (Ar =
4-CH3C6H4)
of TPP. Notably, a new absorption peak appears at
451–475 nm, which is beneficial to improve the light-
harvesting property in the visible region for solar energy
RESULTS AND DISCUSSION
Synthesis and characterization
conversion. Additionally, the Q bands are also broadened
and red shifted compared to TPP. Although the molar
absorption coefficients (e) of cis-N2P are slightly smaller
than those of trans-N2P, the peak positions of cis-N2P
and trans-N2P are almost the same.
Thesyntheticroutesofthemeso-diarylaminoporphyrins
N1P–N4P are shown in Scheme 1. Previously we found
that an iodine(III)-mediated oxidative amination of
meso-free porphyrin is an effective means to prepare
porphyrins with two meso-diarylamino groups [22–25].
Along this line, we aimed to synthesize the meso-
diarylaminoporphyrins by means of meso-free porphyrins
1Zn–3Zn and 4Mg as key precursors. Zinc meso-free
porphyrins 1Zn, cis-2Zn, and trans-2Zn were obtained
by zinc metalation of the corresponding free-base porphy-
rins 1H2, cis-2H2, and trans-2H2. Meanwhile, mono-
substituted 3Zn was synthesized by using the correspon-
ding 1,9-bis(N,N-dimethylaminomethyl)dipyrromethane
[26]. The treatment of 5-phenyldipyrromethane with
N,N-dimethylmethyleneammonium iodide (Eschenmo-
ser’s reagent) [27] and a subsequent reaction with dipyrro-
methane in the presence of Zn(OAc)2 afforded 3Zn in
13% yield. Regarding the synthesis of the porphyrin
with four meso-diarylamoino groups, unsubstituted
magnesium(II) porphine 4Mg was the important inter-
mediate and was prepared according to the literature
[28]. In the next step, the iodine(III)-mediated amination
reaction of the porphyrins 1Zn–3Zn and 4Mg with N,N-
bis(4-methylphenyl)amine provided the corresponding
meso-diarylaminoporphyrins N1P–N4P. Although the
yields of N1P and cis-N2P are moderate (62 and 50%,
respectively), those of trans-N2P, N3P, and N4P are low
(3–20%). The multiple unsubstituted meso-positions may
induce undesirable side reactions under the oxidative
reaction conditions. All the meso-diarylaminoporphyrins
were fully characterized by high-resolution mass spectro-
The steady-state fluorescence spectra of the porphyrins
in CH2Cl2 are also displayed in Fig. 3. As the number
of the diarylamino groups increases, the fluorescence
maximum is shifted toward longer wavelengths with
reducing the intensity, which agrees with the trend of
the absorption properties. The fluorescence lifetimes (tF)
were measured using the time-correlated single-photon
counting (TCSPC) technique (Fig. S8). The tF value of
the meso-aminoporphyrins is decreased gradually with an
increase in the number of the meso-diarylamino groups
(Table 1). The decreasing tendency is probably attributed
to the increased vibrational and rotational degrees of
freedom or enhanced charge-transfer (CT) interaction
as a result of the introduction of the electron-donating
meso-diarylamino groups into the porphyrin core.
From the intersection of the normalized absorption and
fluorescence spectra, the optical HOMO–LUMO gaps
were estimated to be 1.92 eV for TPP, 1.81 eV for N1P,
1.75 eV for cis-N2P and trans-N2P, 1.69 eV for N3P, and
1.64 eV for N4P (Table 1). Because cis-N2P and trans-
N2P exhibit comparable absorption and fluorescence
properties, the position of the meso-diarylamino groups
has little impact on the electronic structures of the
porphyrins.
Electrochemical properties
The electrochemical properties were studied by cyclic
voltammetry (CV) and differential pulse voltammetry
(DPV) techniques in CH2Cl2 vs. ferrocene/ferrocenium
ion (Fc/Fc+) with tetrabutylammonium hexafluoro-
phosphate (Bu4NPF6) as an electrolyte (Fig. S9 and
Table 2). All the meso-diarylaminoporphyins N1P–N4P
exhibit one or two reversible oxidation peaks and two
reversible reduction peaks. As the number of the meso-
diarylamino groups is increased, the first oxidation
potential (Eox1) is significantly shifted to a negative
direction. It is noteworthy that the Eox1 value of N4P
(-0.08 V) is comparable to that of tetrathiafulvalene
1
metry and H NMR and IR spectroscopies (Figs S1–S6
in supporting information). The structure of the meso-
tetraaminoporphyrin N4P has also been supported by its
preliminary X-ray crystal analysis (Fig. S7).
Optical properties
The UV-vis absorption spectra of the meso-diaryl-
aminoporphyrins N1P–N4P and TPP in CH2Cl2 are
depicted in Fig. 2 (see also in Table 1). With increasing
the number of the diarylamino groups, the Soret band
becomes broadened and blue shifted relative to that
Copyright © 2019 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2019; 23: 2–8

EFFECTS OF meso-DIARYLAMINO GROUP OF PORPHYRINS ON OPTICAL AND ELECTROCHEMICAL PROPERTIES
3
Ph
Ph
(4-MeC6H4)2NH
PhI(OAc)2
NH
N
N
N
N
N
N
NaAuCl4•2H2O
Zn(OAc)2
N1P
Ph
Ph
Zn
CH2Cl2/MeOH
CH2Cl2
HN
Ph
Ph
1H2
1Zn
Ph
Ph
(4-MeC6H4)2NH
PhI(OAc)2
NH
N
N
N
N
N
NaAuCl4•2H2O
Zn(OAc)2
cis-N2P
Ph
Ph
Zn
CH2Cl2/MeOH
CH2Cl2
N
HN
cis-2H2
cis-2Zn
Ph
Ph
(4-MeC6H4)2NH
PhI(OAc)2
NH
N
N
N
N
N
N
NaAuCl4•2H2O
Zn(OAc)2
trans-N2P
Zn
CH2Cl2/MeOH
CH2Cl2
HN
Ph
trans-2H2
Ph
trans-2Zn
Ph
Ph
(4-MeC6H4)2NH
PhI(OAc)2
I–
N
CH2
NH HN
Ph
N
N
N
N
NaAuCl4•2H2O
Zn(OAc)2•2H2O
DDQ
N3P
Zn
NH HN
CH2Cl2
EtOH
CH2Cl2
NH HN
NMe2 Me2N
3Zn
(4-MeC6H4)2NH
PhI(OAc)2
N
N
N
N
NaAuCl4•2H2O
N4P
Mg
Ar =
CH3
CH2Cl2
4Mg
Scheme 1. Synthesis of meso-diarylaminoporphyrins N1P–N4P
Fig. 2. UV-vis absorption spectra of (a) TPP, N1P, cis-N2P, and trans-N2P, and (b) TPP, N3P, and N4P in CH2Cl2
Copyright © 2019 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2019; 23: 3–8

4
T. HIGASHINO ET AL.
Table 1. Optical properties of the meso-diarylaminoporphyrins in CH2Cl2
-1
abs, nm (e, 103 M-1 cm )
l
ema, nm
tF, ns
8.4
Eoptb, eV
1.92
.
Porphyrin
TPP
l
418 (500), 516 (19), 550 (7.4), 590 (5.5), 645 (4.1)
413 (220), 451 (33), 592 (11), 668 (5.3)
409 (130), 468 (48), 612 (13), 694 (5.2)
408 (140), 468 (53), 612 (15), 694 (7.2)
402 (73), 474 (60), 638 (13), 713 (6.0)
393 (45), 475 (60), 660 (13), 738 (5.8)
650, 715
702
N1P
4.8
1.81
cis-N2P
trans-N2P
N3P
727
4.0
1.75
727
4.0
1.75
752
3.3
1.69
N4P
783
2.6
1.64
a Wavelength for emission maximum by exciting at 410 nm. b Optical HOMO–LUMO gap.
Fig. 3. Fluorescence spectra of (a) TPP, N1P, cis-N2P, and trans-N2P, and (b) TPP, N3P, and N4P in CH2Cl2. The samples were
excited at 410 nm where the absorbances were adjusted to be identical (0.1) for comparison
(TTF) (-0.07 V) [29], which is a typical donor molecule
for formation of CT complexes with electron acceptors
[30–31]. Thus, the significant electron-rich nature of N4P
is highly promising as a hole-transporting material and
as an electron donor generating versatile CT complexes.
In contrast, the first reduction potential (Ered1) is slightly
shifted to a positive direction with increasing the number
of the meso-diarylamino groups, indicating that meso-
diaryamino groups have no significant impact on the
porphyrin LUMO levels. When the number of the meso-
diarylamino groups is increased, the electrochemical
HOMO–LUMO gaps of N1P–N4P become small
(Table 2), which is in parallel with the trend for the
optical HOMO–LUMO gaps.
Table 2. Electrochemical oxidation and reduction potentials
(vs. Fc/Fc+ ) of the meso-diarylaminoporphyrins in CH2Cl2
Porphyrin Eox2, V Eox1, V Ered1, V Ered2, V Ecva, eV
TPP
0.82
0.54
—
0.52
0.28
0.23
0.18
0.04
-0.08
-1.64
-1.62
-1.60
-1.59
-1.58
-1.56
-1.93
-1.95
-1.94
-1.95
-1.94
-1.96
2.16
1.90
1.83
1.77
1.62
1.48
N1P
cis-N2P
trans-N2P
N3P
—
—
N4P
0.35
a Electrochemical HOMO–LUMO gap.
calculations at the B3LYP/6-31G(d,p) level. The Kohn–
Sham orbitals of N1P–N4P and TPP are depicted in
Fig. S10. For all the meso-diarylaminoporphyrins, the
LUMO and LUMO+1 originate from egx and egy orbitals
Theoretical calculations
To gain further insight into the electronic properties
of the meso-diarylaminoporphyrins, we performed DFT
Copyright © 2019 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2019; 23: 4–8

EFFECTS OF meso-DIARYLAMINO GROUP OF PORPHYRINS ON OPTICAL AND ELECTROCHEMICAL PROPERTIES
5
of TPP. With increasing the number of the meso-
diarylamino groups, the energy levels of the LUMO
and LUMO+1 are slightly lowered, which largely
agrees with the trend for the first and second reduction
potentials. Because the LUMO and LUMO+1 possess
no orbital distributions on the nitrogen atoms of the
meso-diarylamino groups, the small negative shifts of
the LUMO and LUMO+1 levels can be rationalized
by the higher electronegativity of nitrogen atoms than
carbon atoms. Meanwhile, as the number of the meso-
diarylamino groups is increased, the energy level of the
HOMO is raised significantly, which is in good agree-
ment with the trend on the first oxidation potentials. The
HOMO of N1P–N4P largely stem from the a2u orbital of
TPP with significant orbital distributions on the meso-
diarylamino groups. In terms of the introduction of the
meso-diarylamino groups, the a1u orbital of TPP yields
HOMO–1 and HOMO–2 of N1P. On the other hand, the
a1u orbital gives HOMO–2 of cis-N2P and trans-N2P,
HOMO–3 of N3P, and HOMO–4 of N4P. The HOMO–1
of cis-N2P and trans-N2P, HOMO–1 and HOMO–2 of
N3P, and HOMO–1, HOMO–2, and HOMO–3 of N4P
are considerably localized on the meso-diarylamino
groups. These meso-diarylamino-group-based orbitals
are responsible for broadening the absorptions. We also
performed time-dependent DFT (TD-DFT) calculations
at the CAM-B3LYP/6-31G(d) level to evaluate the
absorption (Fig. S11 and Table S1). The calculated
wavelengths of the lowest-energy Q bands for N1P–N4P
(611–653 nm) are red shifted relative to that for TPP
(597 nm). On the contrary, the calculated wavelengths
of the Soret band for N1P–N4P (346–362 nm) exhibit
blue shifts in comparison with those for TPP (370 nm).
Remarkably, for N1P–N4P, calculated new excitations
emerge around 430 nm, which can be assigned to the
new absorption peaks at 451–475 nm. Moreover, the
oscillator strengths of the Q bands for cis-N2P (f =
0.0235–0.0812) are smaller than those for trans-N2P
(f = 0.0369–0.0843), which matches with the smaller
molar absorption coefficient of cis-N2P. Overall, these
TD-DFT calculations verify the absorption properties
of N1P–N4P.
spectrometer (operating at 400 MHz). High-resolution
mass spectra (HRMS) were measured on a Thermo Fischer
ScientificEXACTIVEspectrometerforESImeasurements.
UV-vis absorption spectra were obtained with a Perkin–
Elmer Lambda 900 UV-vis/NIR spectrometer. Steady-
state fluorescence spectra were recorded by a HORIBA
Nanolog spectrofluorometer.
Synthesis
5,10,15-Triphenylporphyrin(1H2)[32],5,10-diphenyl-
porphyrin (cis-2H2) [33], (5,15-diphenylporphyrinato)
zinc(II) (trans-2Zn) [34], and magnesium(II) porphine
(4Mg) [28] were synthesized according to procedures in
the literature.
(5,10,15-Triphenylporphyrinato)zinc(II) (1Zn). To a
solutionof1H2 (46mg, 0.085mmol)inCH2Cl2 (10mL)and
MeOH (5 mL), Zn(OAc)2 (78 mg, 0.42 mmol) was added
and stirred 5 h. The reaction mixture was concentrated
and purified by silica-gel column chromatography (1:1
hexane/CH2Cl2) to give 1Zn (50 mg, 0.083 mmol, 98%) as
a purple solid. 1H NMR (400 MHz, CDCl3) [35]: dH, ppm
10.24 (s, 1H, meso-H), 9.39 (d, J = 4.8 Hz, 2H, b-H), 9.09
(d, J = 4.4 Hz, 2H, b-H), 8.98 (d, J = 4.0 Hz, 4H, b-H), 8.23
(m, 6H, Ph), 7.82 (m, 9H, Ph), 7.75 (m, 6H, Ph).
5-[N,N-bis(4-methylphenyl)amino]-10,15,20-tri-
phenylporphyrin (N1P). To a stirred solution of 1Zn
(40 mg, 0.066 mmol) and bis(4-methylphenyl)amine
(66 mg, 0.33 mmol) in CH2Cl2 (30 mL), PhI(OAc)2
.
(21 mg, 0.066 mmol) and NaAuCl4 2H2O (40 mg,
0.10 mmol) were added. After 30 min, the reaction was
quenched with aqueous saturated Na2S2O3 and the layers
were separated. The organic layer was washed with brine,
dried over Na2SO4, and concentrated. The crude product
was purified by silica-gel column chromatography (2:1
hexane/CH2Cl2) and reprecipitation from CH2Cl2/MeOH
to give N1P (30 mg, 0.041 mmol, 62%) as a green solid.
1H NMR (CDCl3, 400MHz): dH, ppm 9.22 (d, J = 4.9 Hz,
2H, b-H), 8.76 (s, 4H, b-H), 8.71 (d, J = 4.9 Hz, 2H,
b-H), 8.16 (m, 6H, Ph), 7.78–7.68 (m, 9H, Ph), 7.20 (d,
J = 8.3 Hz, 4H, Ar-H), 6.97 (d, J = 8.3 Hz, 4H, Ar-H),
2.23 (s, 6H, CH3), -2.45 (s, 2H, NH). HR-MS (ESI): m/z
733.3194 (calcd. for C52H39N5; [M]•+ 733.3200). UV-vis
(CH2Cl2): lmax, nm (log e) 413 (5.34), 451 (4.52), 592
(4.04), 665 (3.72). Fluorescence (CH2Cl2, lex = 410 nm):
EXPERIMENTAL
l
max, nm 702. FT-IR (ATR): n, cm-1 1502, 1468, 1438,
1346, 1313, 1285, 1256, 1176, 964, 795, 723, 698, 640,
505, 417. Mp > 300°C.
General
(5,10-Diphenylporphyrinato)zinc(II) (cis-2Zn). To
a solution of cis-2H2 (62 mg, 0.13 mmol) in CH2Cl2
(35 mL) and MeOH (10 mL), Zn(OAc)2 (123 mg,
0.67 mmol) was added and stirred overnight. The reaction
mixture was concentrated and purified by silica-gel
column chromatography (1:1 hexane/CH2Cl2) to give cis-
2Zn (66 mg, 0.12 mmol, 92%) as a purple solid. 1H NMR
(400 MHz, CDCl3) [36]: dH, ppm 10.24 (s, 2H, meso-H),
9.47 (s, 2H, b-H), 9.41 (d, J = 4.4 Hz, 2H, b-H), 9.12
Commercially available solvents and reagents were
used without further purification unless otherwise
mentioned. Triethylamine was distilled from CaH2.
Silica-gel column chromatography and alumina column
chromatography were performed with UltraPure Silica
Gel (230–400 mesh, SiliCycle) and Alumina, Activated
(about 300 mesh, Wako). Thin-layer chromatography
(TLC) was performed with Silica gel 60 F254 (Merck).
1H NMR spectra were recorded with a JEOL EX-400
Copyright © 2019 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2019; 23: 5–8

6
T. HIGASHINO ET AL.
.
(d, J = 4.4 Hz, 2H, b-H), 9.02 (s, 2H, b-H), 8.25 (m, 4H,
Ph), 7.82–7.75 (m, 6H, Ph).
2.5 mmol) in ethanol (240 mL), Zn(OAc)2 2H2O
(5.5 g, 25 mmol) was added and refluxed for 2 h. The
reaction mixture was cooled to room temperature and
DDQ (1.7 g, 7.5 mmol) was added. After 15 min, the
reaction was quenched with triethylamine (1.8 mL).
After removal of the solvent, the crude product was
purified by silica-gel column chromatography (1:1
hexane/CH2Cl2) to give 3Zn (152 mg, 0.34 mmol, 13%)
5,10-Bis[N,N-bis(4-methylphenyl)amino]-15,20-
diphenylporphyrin (cis-N2P). To a stirred solution of
cis-2Zn (55 mg, 0.10 mmol) and bis(4-methylphenyl)
amine (103 mg, 0.52 mmol) in CH2Cl2 (35 mL),
.
PhI(OAc)2 (34 mg, 0.10 mmol) and NaAuCl4 2H2O
(62 mg, 0.16 mmol) were added. After 30 min,
the reaction was quenched with aqueous saturated
Na2S2O3 and the layers were separated. The organic
layer was washed with brine, dried over Na2SO4, and
concentrated. The crude product was purified by silica-
gel column chromatography (1:1 hexane/CH2Cl2) and
reprecipitation from CH2Cl2/hexane to give cis-N2P
1
as a purple solid. H NMR (400 MHz, CDCl3) [37]:
dH, ppm 10.37 (s, 2H, meso-H), 10.32 (s, 1H, meso-H),
9.56 (s, 4H, b-H), 9.48 (d, J = 4.4 Hz, 2H, b-H), 9.18
(d, J = 4.4 Hz, 2H, b-H), 8.27 (m, 2H, Ph), 7.80 (m,
3H, Ph).
5-Phenyl-10,15,20-tris[N,N-bis(4-methylphenyl)
amino]porphyrin (N3P). To a stirred solution of 3Zn
(130 mg, 0.29 mmol) and bis(4-methylphenyl)amine
(570 mg, 2.9 mmol) in CH2Cl2 (400 mL), PhI(OAc)2
1
(43 mg, 0.050 mmol, 50%) as a green solid. H NMR
(CDCl3, 400MHz): dH, ppm 9.12 (d, J = 4.4 Hz, 4H,
b-H), 9.10 (s, 2H, b-H), 8.67 (s, 2H, b-H), 8.62 (d,
J = 4.4 Hz, 2H, b-H), 8.09 (m, 4H, Ph), 7.72–7.64 (m,
6H, Ph), 7.17 (d, J = 8.8 Hz, 8H, Ar-H), 6.96 (d, J =
8.8 Hz, 8H, Ar-H), 2.22 (s, 12H, CH3), –2.15 (s, 2H,
NH). HR-MS (ESI): m/z 852.3929 (calcd. for C60H48N6;
[M]•+ 852.3935). UV-vis (CH2Cl2): lmax, nm (log e) 409
(5.11), 468 (4.68), 612 (4.11), 694 (3.72). Fluorescence
(CH2Cl2, lex = 410 nm): lmax, nm 727. FT-IR (ATR): n,
cm-1 1501, 1469, 1346, 1313, 1286, 1258, 975, 963, 795,
777, 755, 720, 698, 660, 639, 487, 422. mp >300°C.
5,15-Bis[N,N-bis(4-methylphenyl)amino]-10,20-
diphenylporphyrin (trans-N2P). To a stirred solution of
trans-2Zn (40 mg, 0.076 mmol) and bis(4-methylphenyl)
amine (75 mg, 0.38 mmol) in CH2Cl2 (80 mL), PhI(OAc)2
.
(186 mg, 0.58 mmol) and NaAuCl4 2H2O (345 mg,
0.87 mmol) were added. After 30 min, the reaction was
quenched with aqueous saturated Na2S2O3 and the layers
were separated. The organic layer was washed with brine,
dried over Na2SO4, and concentrated. The crude product
was purified by silica-gel column chromatography (2:1
hexane/CH2Cl2) and reprecipitation from CH2Cl2/MeOH
to give N3P (10 mg, 0.010 mmol, 3%) as a dark green
solid. 1H NMR (CDCl3, 400 MHz): dH, ppm 9.05 (d, J =
4.8 Hz, 2H, b‑H), 9.01 (q, J = 4.4 Hz, 4H, b-H), 8.55
(d, J = 4.8 Hz, 2H, b-H), 8.04 (m, 2H, Ph), 7.69–7.62
(m, 3H, Ph), 7.13 (m, 12H, Ar-H), 6.96 (m, 12H, Ar-H),
2.23 (s, 18H, CH3), -1.86 (s, 2H, NH). HR-MS (ESI): m/z
971.4658 (calcd. for C68H57N7; [M]•+ 971.4670). UV-vis
(CH2Cl2): lmax, nm (log e) 402 (4.86), 474 (4.78), 638
(4.11), 713 (3.78). Fluorescence (CH2Cl2, lex = 410 nm):
.
(24 mg, 0.076 mmol) and NaAuCl4 2H2O (45 mg,
0.11 mmol) were added. After 30 min, the reaction was
quenched with aqueous saturated Na2S2O3 and the layers
were separated. The organic layer was washed with brine,
dried over Na2SO4, and concentrated. The crude product
was purified by silica-gel column chromatography (2:1
hexane/CH2Cl2) and reprecipitation from CH2Cl2/hexane
to give trans-N2P (10 mg, 0.012 mmol, 16%) as a green
l
max, nm 752. FT-IR (ATR): n, cm-1 1606, 1502, 1469,
1346, 1314, 1287, 1262, 797, 772, 702, 508, 448. mp
>300°C.
5,10,15,20-Tetrakis[N,N-bis(4-methylphenyl)amino]
porphyrin (N4P). To a stirred solution of 4Mg (100 mg,
0.30 mmol) and bis(4-methylphenyl)amine (593 mg,
3.0 mmol) in CH2Cl2 (100 mL), PhI(OAc)2 (194 mg,
1
solid. H NMR (CDCl3, 400MHz): dH, ppm 9.14 (d, J =
4.9 Hz, 4H, b-H), 8.63 (d, J = 4.9 Hz, 4H, b-H), 8.09 (d,
J = 6.4 Hz, 4H, Ph), 7.67 (m, 6H, Ph), 7.18 (d, J = 8.3 Hz,
8H, Ar-H), 6.97 (d, J = 8.3 Hz, 8H, Ar-H), 2.23 (s, 12H,
CH3), -2.13 (s, 2H, NH). HR-MS (ESI): m/z 852.3929
(calcd. for C60H48N6; [M]•+ 852.3935). UV-vis (CH2Cl2):
lmax nm (log e) 408 (5.15), 468 (4.72), 612 (4.18), 694
(3.86). Fluorescence (CH2Cl2, lex = 410 nm): lmax, nm
727. FT-IR (ATR): n, cm-1 1604, 1503, 1470, 1442, 1345,
1315, 1294, 1258, 1028, 972, 794, 698, 659, 509, 413.
mp > 300°C.
.
0.60 mmol) and NaAuCl4 2H2O (359 mg, 0.90 mmol)
were added. After 20 min, the reaction was quenched
with aqueous saturated Na2S2O3 and the layers were
separated. The organic layer was washed with brine,
dried over Na2SO4, and concentrated. The crude product
was purified by silica-gel column chromatography (2:1
hexane/CH2Cl2) and reprecipitation from CH2Cl2/hexane
to give N4P (64 mg, 0.059 mmol, 20%) as a dark brown
1
solid. H NMR (400 MHz, CDCl3): dH, ppm 8.93 (s,
(5-Phenylporphyrinato)zinc(II) (3Zn). To a stirred
solution of 5-phenyldipyrromethane (558 mg, 2.5 mmol)
in CH2Cl2 (40 mL), N,N-dimethylmethyleneammonium
iodide (975 mg, 5.3 mmol) was added. After 1 h, the
reaction mixture was quenched with aqueous NaHCO3
(100mL)andthelayerswereseparated.Theorganiclayer
was dried over Na2SO4 and concentrated. To a stirred
solution of the residue and dipyrromethane (367 mg,
8H, b-H), 7.11 (d, J = 8.8 Hz, 16H, Ar-H), 6.95 (d, J =
8.8 Hz, 16H, Ar-H), 2.22 (s, 24H, CH3), -1.60 (s, 2H,
NH). HR-MS (ESI): m/z 1090.5406 (calcd. for C76H66N8;
[M]•+ 1090.5405). UV-vis (CH2Cl2): lmax, nm (log e) 393
(4.65), 475 (4.78), 660 (4.11), 738 (3.76). Fluorescence
(CH2Cl2, lex = 410 nm): lmax, nm 783. FT-IR (ATR): n,
cm-1 1606, 1502, 1316, 1287, 1266, 798, 775, 753, 703,
596, 505, 422, 405. mp >300°C.
Copyright © 2019 World Scientific Publishing Company
J. Porphyrins Phthalocyanines 2019; 23: 6–8

EFFECTS OF meso-DIARYLAMINO GROUP OF PORPHYRINS ON OPTICAL AND ELECTROCHEMICAL PROPERTIES
7
Electrochemistry
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diameter) working electrode, a Ag/AgNO3 reference
electrode, and a Pt wire counter electrode were employed.
Ferrocene was used as an external standard for the DPV
measurements.
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We reported a series of meso-diarylaminoporphyrins
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Supporting information
Figures S1–S11 and Table S1 are given in the
supplementary material. This material is available free of
charge via the Internet at http://www.worldscinet.com/
jpp/jpp.shtml.
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J. Porphyrins Phthalocyanines 2019; 23: 7–8

8
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