Efficient synthesis of novel porphyrin dimers with versatile linkers via bis(dipyrromethanes) in an excellent mixed-solvent

Article abstract of DOI:10.1071/CH12521

A general and efficient protocol has been developed to synthesise a series of novel porphyrin dimers with versatile aryl linkers via a simultaneous condensation-cyclisation-oxidation reaction of diverse bis(dipyrromethanes) with dipyrromethane-dicarbinol

Full text of DOI:10.1071/CH12521

CSIRO PUBLISHING
Aust. J. Chem. 2013, 66, 972–982
Full Paper
http://dx.doi.org/10.1071/CH12521
Efficient Synthesis of Novel Porphyrin Dimers
with Versatile Linkers via Bis(dipyrromethanes)
in an Excellent Mixed-Solvent
A B C
, ,
A
A
A B
,
Hongbin Zhao,
Junxu Liao, Deliang Yang, Yujia Xie,
A
A
A B
,
Yongjun Xu, Hongke Wang, and Bangying Wang
A
College of Chemistry and Environmental Engineering, Dongguan University of
Technology, Guangdong 523808, China.
B
College of Chemistry, Xiangtan University, Hunan 411105, China.
C
Corresponding author. Email: zhaohbhanlf@163.com
A general and efficient protocol has been developed to synthesise a series of novel porphyrin dimers with versatile
aryl linkers via a simultaneous condensation-cyclisation-oxidation reaction of diverse bis(dipyrromethanes) with
dipyrromethane-dicarbinol catalysed by indium(III) chloride at room temperature in an efficient CH2Cl2 and CH3CN
mixed-solvent. The reaction yields increased to 21–26 % based on liquid chromatography-mass spectrometry (LCMS) and
isolated yields were 13–19 % due to the use of the proper mixed-solvent. This mild method is applicable to the preparation
of linker-tunable porphyrin dimers with targeted functionalities and could potentially be extended to the single-step
construction of longer functionalised multiporphyrin arrays.
Manuscript received: 22 November 2012.
Manuscript accepted: 2 May 2013.
Published online: 29 May 2013.
during the dipyrromethane-dicarbinol[9] and bis(dipyrro-
methanes) acidolysis reactions.[10] The ‘2þ2’ method for the
facile construction of multiporphyrin arrays urgently requires
modification for further investigations and applications.
To this end, we developed a protocol in an earlier work in
2010 for preparing the key intermediates, bis(dipyrromethanes),
and obtained one porphyrin dimer in a 12 % yield by modifying
the ‘2þ2’ method.[11] In this report, we further modify the ‘2þ2’
method by using a CH2Cl2/CH3CN mixed-solvent to synthesise
a series of novel porphyrin dimers, bearing various linkers in the
middle and two active groups at the termini, in satisfactory
yields. This protocol should be applicable to the construction of
longer multiporphyrin arrays, such as porphyrin trimers, tetra-
mers, pentamers and so on. Therefore, our work offers a chance
to further study the synthesis of multiporphyrin compounds and
exploit advances in their promising applications.
Introduction
Covalently linked multiporphyrin arrays have continued to be
synthesised and fabricated for use in molecular devices owing to
their special electronic structures.[1–3] A key factor influencing
the properties and functionality of these compounds is the
electronic interaction between both the constituent porphyrin
rings and the embedded linkers.[2,4] Therefore, diverse por-
phyrin dimers or multiporphyrin arrays are urgently required for
basic properties research. However, this task has been seriously
restricted by inefficient synthetic techniques. Recently, con-
siderable attention has been paid to binding multiple porphyrin
units into functionalised arrays using numerous types of linkers
in a simple, feasible way.[5] The typical method for constructing
multiporphyrin arrays is to couple intact porphyrin building
blocks.[6] However, this inconvenient stepwise approach only
introduces fixed linkers into the porphyrin backbones, which
severely limits the possible diversity and functionality of the
multiporphyrin arrays. Another approach is the ‘2þ2’ method
first reported by MacDonald[7] and exploited by Lindsey.[8] This
method is a well known and potentially important strategy
because the key intermediate compound in this method, bis
(dipyrromethanes) can be designed to contain changeable lin-
kers that can then, theoretically, be condensed in one step to
afford diverse multiporphyrin arrays with targeted functionality.
However, to the best of our knowledge, only a few porphyrin
dimers have been produced via this ‘2þ2’ method with yields
below 8 %,[8] and multiporphyrin arrays containing more por-
phyrin units have not yet been obtained due in part to the
competing reaction between the a and b positions on pyrrole
Results and Discussion
With the ultimate objective of developing an efficient and
general method for constructing porphyrin dimers for basic
photoelectric performance research, nine types of linked bis
(dipyrromethanes), 3, were selected for this work. For example,
both conjugated linkers with different conjugation lengths, such
as phenylene, biphenylene, triphenylene, and triphenylenevi-
nylene, and non-conjugated linkers, such as diphenylether and
1,4-diphenoxybenzene, were included. In addition, three types
of classical photoelectric materials, triphenyl amine, carbazole,
and diphenyl fluorene, were introduced as linkers. These linkers
Journal compilation Ó CSIRO 2013
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Porphyrin Dimers
973
endowed the porphyrin dimers with different distances between
the adjacent porphyrin rings. Moreover, all of these linkers
provide diverse steric configurations with different spatial
positions between the porphyrin units. For example, phenylene,
biphenylene, and triphenylene make the whole molecular
structure linear, while triphenyl amine makes it pyramidal,
where the two porphyrin planes present different dihedral angles
in these latter porphyrin dimers.[12] In addition to the above,
porphyrin dimers substituted with -Br at the termini are func-
tionalised for further Suzuki or Heck coupling and such dimers
can be readily converted into advanced functional molecules
such as porphyrinic macrocycle-polymers[13] or photosensitive
dyes.[14] From a synthetic standpoint, the applied protocol for
constructing porphyrin dimers using such versatile and chal-
lenging linked bis(dipyrromethanes), 3, may be considered
general, and the relatively high efficiency may be considered an
advancement relative to those previously reported.
reaction for studying the influence of different solvent systems
on the reaction yield. To obtain credible data, each experiment
was repeated three times. We first examined several individual
solvents, such as THF, CH3CN, EtOAc, CH2Cl2, and CHCl3,
before investigating several mixed solvents.
Table 1 shows how the diverse solvent systems influenced
the PDa synthesis with yields ranging from 17–25 % based on
LCMS. The CH2Cl2/CH3CN mixed-solvent (19 : 1) exhibited an
especially positive effect on the reaction and gave the highest
isolated yield, 18 %, which was an increase over previous
results. Therefore, we supplemented the model reaction condi-
tions using this solvent mixture. Thus, the optimised synthetic
conditions using InCl3 as catalyst were bis(dipyrromethane), 3,
to dipyrromethane-dicarbinol, 4, ratio of 1 : 2.2 using CH2Cl2/
CH3CN (19 : 1) as the reaction solvent under an argon atmo-
sphere for 30 min before oxidising the protoporphyrin with
Chloranil (5.0 equiv.) in air for 6 h.
With these advantages in mind, a series of phenylene-,
biphenylene-, triphenylene-, triphenylenevinylene-, diphenyl-
ether-, 1,4-diphenoxy-benzene-, carbazole-, triphenyl amine-,
and diphenyl fluorene-linked dialdehydes, 1, was first prepared.
We used an alkylation-bromomethylation-acetylation-reduction-
oxidation-Wittig reaction to transform 1,4-hydroquinone into
the phenylene-linked dialdehydes (1a–1c), triphenylenevinylene-
linked dialdehydes (1g–1h) and diphenyl fluorene-linked dia-
ldehyde (1m).[11,15] Both a Miyaura cross-coupling and Suzuki
coupling reaction or a Suzuki bis-coupling reaction were used to
synthesise the biphenylene-linked dialdehydes (1d–1e) and
triphenylene-linked dialdehyde (1f).[11] The diphenylether-
linked dialdehyde (1i) and 1,4-diphenoxybenzene-linked dia-
ldehyde (1j) were synthesised via a condensation reaction
between either 4-bromobenzaldehyde and 4-hydroxybenzene
or 4,40-dihydroxybenzene,[16] and dialdehyde 1l was obtained
via the oxidation of N,N-diphenyl-4-bromophenylamine by
POCl3.[17]
With this library of dialdehydes in hand, our attention shifted
to the synthesis of the important bis(dipyrromethane) intermedi-
ates, 3. Scheme 1 illustrates this synthesis, which used identical
or slightly modified synthetic conditions to those reported by
our group.[11] A neat reaction between pyrrole and the above
synthesised dialdehydes (160 : 1) was catalysed by InCl3
(0.2 equiv.) at room temperature for 30 min. After a simple
purification, the corresponding bis(dipyrromethanes), 3, were
readily obtained in satisfactory yields (.80 %) and high quality.
With these novel bis(dipyrromethanes) in hand, we focussed
on finding an efficient synthetic strategy for constructing
versatile porphyrin dimers. In our previous work, we established
a condensation-cyclisation-oxidation reaction model for the
facile construction of porphyrin dimers, which involves the
InCl3-catalysed condensation of a bis(dipyrromethane), 3a
(1.0 equiv.) with dipyrromethane-dicarbinol, 4 (3.0 equiv.), fol-
lowed by an oxidation using 2,3,5,6- tetrachlorocyclohexa-2,5-
diene-1,4-dione (Chloranil, 5.0 equiv.) to afford the porphyrin
dimer PDa (Scheme 2) in 12 % yield. To further improve the
synthetic efficiency, we investigated all of the factors that may
influence the porphyrin dimer yield, including the reaction
temperature, reaction time, solvent, and catalyst. Most of these
factors did not have a positive impact on the yield; however, we
found that the reaction solvent greatly influences the yields after
the Chloranil oxidation, based on liquid chromatography-
mass spectrometry (LCMS) analysis. Thus, we used the
condensation reactions of bis(dipyrromethane), 3a (1.0 equiv.)
with dipyrromethane-dicarbinol, 4 (2.2 equiv.) as the model
Based on the success of this protocol in preparing PDa, we
used identical conditions to construct the other 12 porphyrin
dimers shown in Scheme 2.
All nine types of linked bis(dipyrromethanes), 3, readily
formed the corresponding porphyrin dimers with yields ranging
from 13 to 19 % (Table 2) in .95 % purity based on HPLC,
which showed that this reaction model can be successfully
exploited as a general and efficient protocol in the proper
mixed-solvent.
The poor solubility of the reactants was efficiently improved
by using the organic mixed-solvent, which included a sufficiency
of CH2Cl2 and a small amount of CH3CN. Introducing alkyloxy
chains of appropriate length can improve the solubility of
organic compounds in organic solvents, while chains that are
too long will create strong stereo-hindrance rather than good
solubility. As shown in Table 2, the porphyrin dimer yields
were increased by lengthening the alkyloxy chain because the
solubility of the bis(dipyrromethanes) and porphyrin dimers
improved upon the introduction of alkyl chains with the appro-
priate length (PDa-PDb; PDd-PDe) but decreased due to
the strong stereo-hindrance (PDb-PDc).
Absorption spectra of the porphyrin dimers were collected in
CH2Cl2 (Table 3, Fig. 1, and Supplementary Material) for
original photoelectric performance research.
The porphyrin dimers containing phenylene, biphenylene,
triphenylene, triphenylenevinylene, diphenylether, 1,4-diphenoxy-
benzene, triphenylamine, carbazole, and diphenylfluorene
linkers all exhibited four peaks characteristic of porphyrin,
which confirmed the formation of these porphyrin dimers. All
the obtained porphyrin dimers showed similar Soret bands at
,420 and 423 nm as well as visible bands at ,515, 550, 588,
and 646 nm. Fig. 2 (we choose the PDc for example) shows that
Soret bands of these porphyrin dimers were at 422 nm with a
bathochromic shift (,2–4 nm) compared with tetraphenyl por-
phyrin (TPP) due to some of the phenyls being substituted with
electron-rich or electron-deficient groups. The visible bands of
these porphyrin dimers were identical with TPP except for PDg
and PDk which have longer wavelengths of the IV bands due to
the extra conjugation. However, we didn’t see obvious shifts and
splittings among the porphyrin dimers because of the various
geometries and differing lengths of the linkers. This may be
interpreted as the porphyrin moieties being the main chromo-
phores in these molecules; the bridging groups extend the
p-conjugation and reduce the electron cloud density in varying
degrees, but this shows little effect on the porphyrin chromo-
phores. On the other hand, from the spectra of absolute

974
H. Zhao et al.
NH
NH
HN
HN
InCl3, Ar, rt
Linker
Linker
OHC
CHO
ϩ
N
H
1
2
3
Linker:
OC4H9
OC4H9
OC4H9
OC4H9
C4H9O
C10H21
N
C4H9O
C4H9O
C4H9O
1a
1b
1f
1k
OC7H15
OC8H17
OC7H15
Br
OC7H15
C7H15
O
C8H17
O
C7H15
O
C7H15
O
1g
N
OC10H21
OC4H9
OC8H17
OC4H9
1l
C10H21
O
C4H9O
1c
1d
C8H17
O
C4H9O
1h
C8H17
C8H17
O
O
OC4H9
OC4H9
1i
1j
1m
O
C4H9O
C4H9O
1e
Scheme 1. Synthesis of bis(dipyrromethanes).
absorbance (see Supplementary Material), we can see that
PDd, PDe, PDg, PDi, PDj, and PDk, showed stronger absorp-
(dipyrromethanes) and porphyrin dimers. It is important to note
that we successfully established a general route to afford a
variety of bridging group-linked porphyrin dimers with desir-
able yields. This efficient protocol is applicable to constructing
numerous types of porphyrin dimers with tunable, functional
linkers. Furthermore, this protocol should extend to the single-
step construction of longer functionalised multiporphyrin
arrays. Further studies on the synthesis of more novel functio-
nalised porphyrin dimers and even trimers based on this pow-
erful route are in progress in our laboratory.
tion at identical concentrations in
(c ¼ 1 ꢀ 10ꢁ5 mol Lꢁ1).
a CH2Cl2 solution
Conclusion
In summary, a series of novel porphyrin dimers containing
phenylene, biphenylene, triphenylene, triphenylenevinylene,
diphenylether, 1,4-diphenoxybenzene, triphenylamine, carba-
zole, and diphenylfluorene linkers were synthesised under mild
conditions, at room temperature, through the simultaneous
condensation-cyclisation-oxidation reaction of bis(dipyrro-
methanes) with dipyrromethane-dicarbinol, under catalysis by
InCl3 in a CH2Cl2 and CH3CN mixed-solvent, with satisfactory
yields ranging from 13 to 19 %. Such yields are acceptable for
the one step synthesis of porphyrin dimers. By introducing
alkyloxy chains and using a suitable organic mixed-solvent,
we efficiently improved the poor solubility of the bis
Experimental
General
1H and 13C NMR spectra were recorded on a Bruker Avance
(400 and 100 MHz, respectively). All melting points are
uncorrected. The mass spectra were obtained via matrix-assisted
laser desorption ionisation mass spectrometry (MALDI-MS)
using an a-cyano-4-hydroxy-cinnamic acid (a-CHCA) matrix.

Porphyrin Dimers
975
OH
OH
NH
NH
HN
HN
NH
NH
Linker
Br
ϩ
4†
3
1) InCl3,
CH2Cl2/CH3CN
HN
N
N
HN
N
Br
Linker
PD
Br
2) TCQ, rt
N
NH
NH
Linker:
a
OC4H9
OC4H9 OC4H9
OC4H9
C10H21
N
f
k
C4H9O
C4H9O C4H9O
C4H9O
OC7H15
OC8H17
OC7H15
C7H15
Br
N
b
c
OC7H15
g
O
C8H17O
l
C7H15
O
C7H15O
OC10H21
OC4H9
OC8H17
OC4H9
C8H17
C10H21O
h
C4H9O
O
C4H9O
C8H17
C8H17
d
e
i
j
O
OC4H9 OC4H9
m
O
O
C4H9O
C4H9O
†Details of this synthesis are described in the Experimental Section.
Scheme 2. Synthesis of porphyrin dimers.
Silica gel (40 mm average particle size) was used for column
chromatography. Thin-layer chromatography was performed
using SiliCycle silica gel 60 F254 TLC plates and visualised with
ultraviolet light. All compounds were purchased from Alfa-
Aesar and used without further purification unless otherwise
noted. Pyrrole was distilled from CaH2 before use. THF,
CH3OH and toluene were freshly distilled from CaH2. 1g,[11]
1j,[16] 4,40-oxydibenzaldehyde,[16] 1k,[18] 3a,[11] 3b,[11] 3c,[11] and
3d[11] were synthesised according to the literature procedures and
verified by 1H NMR and MS. 4-Bromobenzaldehyde was
commercially available.
Synthesis of Dialdehydes
2,5,30,60-Tetrabutoxybiphenyl-4,40-dicarbaldehyde (1e)
A
modified literature procedure was used for this
reaction.[11] A mixture of 2,5-dibutoxy-4-formyl-1-(4,4,5,5-
tetramethyl1,3,2-dioxaboralane-2-yl)benzene (3.76g, 10 mmol),

976
H. Zhao et al.
Table 1. Solvents used for the construction of PDa
solid (2.99 g, 60 %). M.p. 54–578C. 1H NMR (400 MHz, CDCl3)
d 10.50 (s, 2H), 7.38 (s, 2H), 6.95 (s, 2H), 4.04 (t, J ¼ 6.3 Hz,
4H), 3.92 (t, J ¼ 6.4 Hz, 4H), 1.80 (m, 4H), 1.59 (m, 4H),
1.51 (m, 4H), 1.31 (m, 4H), 0.98 (t, J ¼ 7.3 Hz, 6H), 0.86
(t, J ¼ 7.3 Hz, 6H); 13C NMR (100 MHz, CDCl3) d 189.46,
155.75, 150.65, 135.17, 124.97, 116.74, 110.49, 69.24, 69.00,
31.45, 31.40, 19.42, 19.30, 13.88, 13.83; m/z (MALDI-TOF)
498.273; [MþH]þ requires 498.298.
Entry Solvent [v/v]
(60 mL)
Temp Time
[h]
LCMS
yield
[%]
Isolated
yield
[%]
1
CH2Cl2
rt
rt
rt
rt
rt
rt
rt
rt
rt
rt
rt
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
19
19
19
17
18
19
19
23
25
25
23
12
13
13
12
12
14
13
17
18
18
17
2
CHCl3
3
CH3CN
4
EtOAc
5
THF
2,5-Dibutoxy-1,4-bis[2,5-bis(butoxy)-4-formylphenyl]
benzene (1f)
6
CH2Cl2/THF (9 : 1)
CH2Cl2/EtOAc (9 : 1)
CH2Cl2/CH3CN (9 : 1)
CH2Cl2/CH3CN(14 : 1)
CH2Cl2/CH3CN(19 : 1)
CH2Cl2/CH3CN(24 : 1)
7
A modified literature procedure was used for this reaction.[11]
Pd(PPh3)4 (578 mg, 0.5mmol) and Na2CO3 (30 mL, 2M in water)
were added to a solution of 4-bromo-2,5-dibutoxybenzaldehyde
(3.62 g, 11.0 mmol) and 2,5-dibutoxy-1,4-bis(4,4,5,5-tetramethyl-
1,3,2-dioxaboralane-2-yl)benzene (2.37 g, 5.0 mmol) in toluene
(30 mL), and the mixture was stirred under an argon atmosphere
at 908C for 24 h. After the reaction had cooled to room
temperature, water (150 mL) was added to the flask, and the
mixture was extracted with CH2Cl2 (3 ꢀ 100 mL). The organic
phase was collected, washed with a saturated salt solution
(3 ꢀ 80 mL), and dried over anhydrous MgSO4. After concen-
trating on a rotary evaporator, the solution was purified by silica
gel chromatography (eluting with petroleum ether/EtOAc ¼
30 : 1) to obtain the desired compound, 1f, as a yellow solid
(2.27 g, yield 61 %).M.p. 98–1008C. 1H NMR (400 MHz,
CDCl3) d 10.51 (s, 2H), 7.40 (s, 2H), 7.05 (s, 2H), 6.95
(s, 2H), 4.06 (t, J ¼ 6.3 Hz, 4H), 3.95 (t, J ¼ 6.5 Hz, 4H), 3.86
(t, J ¼ 6.5 Hz, 4H), 1.81 (dd, J ¼ 14.3, 6.7 Hz, 4H), 1.71–1.56
(m, 8H), 1.56–1.45 (m, 4H), 1.43–1.23 (m, 8H), 0.99 (t, J ¼
7.4 Hz, 6H), 0.86 (dt, J ¼ 10.7, 7.4 Hz, 12H). 13C NMR
(100 MHz, CDCl3) d 189.74, 156.01, 151.07, 150.14, 136.48,
127.70, 124.62, 117.46, 116.79, 110.72, 69.54, 69.30, 69.19,
31.80, 31.63, 31.60, 19.58, 19.47, 19.45, 14.04, 14.01, 14.00.
m/z (MALDI-TOF) 718.445; [MþH]þ requires 718.534.
8
9
10
11
Table 2. Yields for the porphyrin dimers under optimised conditions
Porphyrin
dimers
LCMS
yield
[%]
Isolated
yield
Porphyrin
dimers
LCMS
yield
[%]
Isolated
yield
[%]
[%]
PDa
PDb
PDc
PDd
PDe
PDf
PDg
26
26
25
24
25
26
23
18
19
18
17
18
18
16
PDh
PDi
22
25
26
23
23
22
16
18
18
14
13
14
PDj
PDk
PDl
PDm
Table 3. Absorption spectral data of porphyrin dimersA
Cpd
Soret (V)
e [103 mol Lꢁ1 cmꢁ1
Visible e [103 mol Lꢁ1 cmꢁ1
]
]
(IV)
(III)
(II)
(I)
2,5-Bis(octyloxy)-1,4-bis[(2,5-bis(butoxy)-4-formyl)
phenylenevinylene]benzene (1h)
TPP
PDa
PDb
PDc
PDd
PDe
PDf
PDg
PDh
PDi
418 (134)
420,423 (171)
420,422 (152)
420,422 (174)
421,423 (222)
417,423 (240)
423 (162)
515 (7)
550 (5)
589 (4)
587 (7)
588 (5)
645 (3)
645 (5)
645 (4)
514 (18) 548 (9)
515 (13) 551 (7)
A modified literature procedure was used for this reac-
A suspension of 2,5-bis(bromomethyl)-1,4-bis
tion.[11,15]
516 (22) 551 (13) 589 (10) 647 (6)
516 (22) 552 (13) 590 (9)
516 (17) 551 (10) 589 (7)
646 (7)
646 (6)
645 (2)
657 (6)
(octyloxy)benzene (2.86 g, 5.5 mmol) and triphenylphosphine
(3.15 g, 12 mmol) in toluene (90 mL) was refluxed for 3 h. The
solvent was then removed on a rotary evaporator. 2,5-Bis
(butoxy)benzene-1,4-dialdehyde (2.76 g, 10 mmol) and CH2Cl2
(180 mL) were added to the flask followed by the dropwise
addition of a lithium ethoxide solution (14 mL, 1.0 M in ethanol)
via a syringe at room temperature over 10 min. The resulting
solution was allowed to react for 30 min before pouring into
dilute aqueous HCl. The organic layer was separated, washed
with water, and dried over Na2SO4. The residue after solvent
removal contained both the E- and Z-isomers. A solution of this
isomer mixture and iodine (2 g, 7.8 mmol) in CH2Cl2 (90 mL)
was stirred at room temperature overnight. The dark brown
solution was then diluted with CH2Cl2 and washed with an
aqueous Na2S2O3 solution (1.0 M, 2 ꢀ 75 mL) and water. The
organic phase was dried over Na2SO4. After concentrating on a
rotary evaporator, the solution was loaded onto a silica gel
column and eluted with a mixture of hexane and chloroform
(1 : 1) to afford the title compound as a yellow fluorescent solid
516 (7)
552 (4)
590 (3)
426 (266)
525 (20) 562 (12) 600 (6)
421,423 (132)
421,423 (245)
418,423 (198)
423 (202)
515 (26) 552 (17) 588 (13) 647 (8)
515 (42) 550 (27) 589 (20) 646 (13)
514 (32) 550 (20) 588 (14) 646 (9)
PDj
PDk
PDl
524 (20) 561 (10) 603 (6)
517 (18) 555 (11) 592 (9)
660 (4)
648 (6)
646 (4)
419,422 (140)
423 (176)
PDm
516 (12) 552 (8)
590 (5)
AAt room temperature in chloroform.
4-bromo-2,5-dibutoxybenzaldehyde (3.29 g, 10 mmol), Pd(PPh3)4
(0.58 g, 0.5 mmol), toluene (30 mL) and Na2CO3 solution (2 M,
30 mL) was heated to 858C for 24 h under an argon atmosphere.
The catalyst was removed via filtration, and the reaction mixture
was washed with CH2Cl2 after cooling to room temperature. The
organic layer was washed with saturated aqueous NH4Cl
(3 ꢀ 100 mL) and dried over anhydrous MgSO4. After removing
the solvent on a rotary evaporator, the crude product was
purified by column chromatography using silica gel (CH2Cl2/
petroleum ether ¼ 1 : 1) to afford the title compound as a yellow
1
(4.12 g, 94 %). M.p. 150–1518C. H NMR (400 MHz, CDCl3)
d 10.45 (s, 2H), 7.56 (dd, 4H), 7.33 (s, 2H), 7.21 (s, 2H), 7.15
(s, 2H), 4.18–3.94 (m, 12H), 1.93–1.76 (m, 12H), 1.55 (t, 12H),

Porphyrin Dimers
977
1.0
0.9
0.8
0.7
0.6
0.5
0.4
1.0
0.8
0.6
0.4
0.2
0
PDa
PDb
PDc
PDd
PDe
PDf
PDg
PDh
PDi
PDj
PDk
PDl
PDm
405 410 415 420 425 430 435 440 445
Wavelength [nm]
400
500
600
700
Wavelength [nm]
Fig. 1. Normalised absorption spectra of porphyrin dimers in CH2Cl2 solution (c ¼ 1 ꢀ 10ꢁ5 mol Lꢁ1).
2.0
CHCl3 (3 ꢀ 100 mL). The organic layer was separated, washed
with water, dried over Na2SO4 and concentrated on a rotary
evaporator. The residue was purified on a silica gel column
(eluted with petroleum ether) and recrystallised (hexane) to give
the desired compound, 1l, as a green solid (2.47 g, yield 65 %).
422nm
420nm
1.8
1.6
1.4
TPP
PDc
418nm
1
M.p. 205–2078C. H NMR (400 MHz, CDCl3) d 9.91 (s, 2H),
7.79 (d, J ¼ 8.2 Hz, 4H), 7.51 (d, J ¼ 8.3 Hz, 2H), 7.19
1.2
1.0
0.8
0.6
0.4
0.2
0
(d, J ¼ 8.1 Hz, 4H), 7.06 (d, J ¼ 8.2 Hz, 2H).
2,7-Bis(4-formylphenyl)-9,9-dioctylfluorene (1m)
A modified literature procedure was used for this reaction.[19]
A suspension of 2,7-dibromo-9,9-dioctylfluorene (1.65 g,
3 mmol), 4-formylphenyl boronic acid (0.93 g, 6.2 mmol),
Pd(PPh3)4 (347 mg, 0.3 mmol), toluene (25 mL), and 2 M
Na2CO3 solution (25 mL) was refluxed for 24 h under an argon
atmosphere. The reaction mixture was filtered and washed with
CH2Cl2 (50 mL) once it had cooled to room temperature. The
separated organic layer was washed with saturated aqueous
NH4Cl (3 ꢀ 50 mL) and dried over MgSO4. The solvent was
removed on a rotary evaporator, and the crude residues was
purified by column chromatography on silica gel (eluted with
petroleum ether/EtOAc ¼ 12 : 1) to give compound 1m as a pale
TPP
PDc
400
500
600
700
Wavelength [nm]
Fig. 2. Absorption spectra of TPP and PDc in a CH2Cl2 solution
(c ¼ 1 ꢀ 10ꢁ5 mol Lꢁ1).
1.41–1.18 (m, 16H), 1.01 (td, 12H), 0.86 (d, 6H); 13C NMR
(100 MHz, CDCl3) d 189.18, 156.44, 151.55, 150.96, 135.16,
127.70, 127.11, 124.45, 123.45, 111.07, 110.73, 110.43, 69.63,
69.11, 69.03, 31.99, 31.53, 31.51, 29.64, 29.57, 29.46, 26.40,
22.78, 19.58, 19.50, 14.17, 14.05, 13.96; m/z (MALDI-TOF)
883.266; [MþH]þ requires 883.245.
1
green solid (1.16 g, yield 65 %). M.p. 102–1048C. H NMR
(400 MHz, CDCl3) d 10.08 (s, 2H), 7.99 (d, J ¼ 8.0 Hz, 4H), 7.84
(d, J ¼ 8.2 Hz, 6H), 7.66 (d, J ¼ 7.9 Hz, 2H), 7.62 (s, 2H),
2.14–1.99 (m, 4H), 1.22–0.98 (m, 20H), 0.87–0.72 (m, 10H).
13C NMR (100 MHz, CDCl3) d 191.75, 152.08, 147.54, 140.94,
138.93, 135.20, 130.26, 127.69, 126.53, 121.75, 120.49, 55.53,
40.29, 31.71, 29.89, 29.10, 23.80, 22.53, 13.96. m/z (MALDI-
TOF) 598.381; [MþH]þ requires 599.530.
N,N-Bis(4-formylphenyl)-4-bromophenylamine (1l)
A modified literature procedure was used for this reaction.[17]
POCl3 (20 mL) was added dropwise to a solution of N,N-diphenyl-
4-bromophenylamine (3.25 g, 10 mmol) in 1,2-dichloroethane
(50 mL) and DMF (30 mL). The temperature was kept below
08C using an ice salt bath and the resulting mixture was heated
to 908C for 48 h. After cooling to room temperature, the
solution was poured into water (200 mL) and extracted with
Preparation of Bis(dipyrromethanes)
2,5,30,60-Tetrabutoxy-4,40-bis(dipyrromethan-5-yl)
biphenyl (3e)
Compound 1e (645 mg, 1.29 mmol) was dissolved in dry
pyrrole (20 mL, 289 mmol), and the solution was flushed with

978
H. Zhao et al.
argon for 10 min. InCl3 (57 mg, 0.26 mmol) was added, and the
reaction was allowed to proceed for 30 min. The reaction was
quenched with NaOH powder (800 mg, 20 mmol). The mixture
was stirred for 45 min and then filtered. Excess pyrrole was
removed by distilling under reduced pressure, and the resulting
yellow solid was treated with hexanes (10 mL). The solvent was
removed under reduced pressure, and the residue was purified
by column chromatography on silica gel (eluted with hexane/
CH2Cl2/ethyl acetate ¼ 7 : 2 : 1) to give compound 3e as a pale
yellow solid (839 mg, 89 %). M.p. 108–1118C. 1H NMR
(400 MHz, CDCl3) d 8.31 (brs, 4H), 6.90 (s, 2H), 6.78 (s, 2H),
6.68 (s, 4H), 6.14 (m, 4H), 5.97 (s, 4H), 5.71 (s, 2H), 3.82
(t, J ¼ 6.3 Hz, 4H), 3.75 (t, J ¼ 6.2 Hz, 4H), 1.63–1.46 (m, 8H),
1.29 (m, 8H), 0.86 (m, 12H); 13C NMR (100 MHz, CDCl3)
d 150.87, 150.08, 132.83, 131.06, 117.45, 116.69, 116.65,
115.59, 108.37, 106.76, 69.55, 69.53, 39.34, 31.70, 31.68,
31.65, 19.38, 19.35, 19.30, 13.93; m/z (MALDI-TOF)
730.448; [MþH]þ requires 730.446.
1,4-Bis(4-dipyrromethylphenoxy)benzene (3j)
Compound 1j (550 mg, 1.73 mmol) was dissolved in dry
pyrrole (20 mL, 0.30 mol) and flushed with argon for 10 min.
InCl3 (76 mg, 0.35 mmol) was added, and the reaction was
allowed to proceed for 30 min before quenching with powdered
NaOH (0.8 g, 20 mmol). The mixture was stirred for 45 min and
then filtered. Excess pyrrole was removed by distillation under
reduced pressure, and the resulting yellow solid was treated with
hexanes (10 mL). The solvent was removed under reduced
pressure, and the residue was purified by column chromatogra-
phy on silica gel (eluted with CH2Cl2) to afford a pale yellow
solid (0.80 g, 84 %). M.p. 63–668C. 1H NMR (400 MHz, CDCl3)
d 7.96 (brs, 4H), 7.17 (d, J ¼ 8.5 Hz, 4H), 6.98 (d, J ¼ 4.3 Hz,
4H), 6.93 (d, J ¼ 8.5 Hz, 4H), 6.71 (d, J ¼ 1.2 Hz, 4H), 6.16
(d, J ¼ 2.7 Hz, 4H), 5.92 (s, 4H), 5.46 (s, 2H); 13C NMR
(100 MHz, CDCl3) d 156.59, 152.63, 136.82, 132.54, 129.59,
120.40, 118.22, 117.23, 108.37, 107.18, 43.22; m/z (MALDI-
TOF) 549.229; [MþH]þ requires 550.237.
2,5-Dibutoxy-1,4-bis[2,5-bis(butoxy)-4-(dipyrromethan-
5-yl)phenyl]benzene (3f)
2,5-Bis(octyloxy)-1,4-bis{[(2,5-bis(butoxy)-4-
(dipyrromethan-5-yl)]phenylenevinylene} benzene (3h)
Compound 1f (1.8 g, 2.5 mmol) was dissolved in dry
pyrrole (28 mL, 0.4 mol) and flushed with argon for 10 min.
InCl3 (111 mg, 0.5 mmol) was added, and the reaction was
allowed to proceed for 30 min before quenching with NaOH
powder (800 mg, 20 mmol). The mixture was stirred for
45 min and then filtered. Excess pyrrole was removed by
distillation under reduced pressure, and the resulting yellow
solid was treated with hexanes (10 mL). The solvent was
removed under reduced pressure, and the residue was puri-
fied by column chromatography on silica gel (eluted with
hexane/CH2Cl2/ethyl acetate ¼ 7 : 2 : 1) to give the compound
3f as a pale yellow solid (2.1 g, yield 88 %). M.p. 174–1778C;
1H NMR (400 MHz, CDCl3) d 8.31 (s, 4H), 6.98 (s, 2H), 6.95
(s, 2H), 6.80 (s, 2H), 6.69 (s, 4H), 6.15 (d, J ¼ 2.3 Hz, 4H),
5.98 (s, 2H), 5.73 (s, 1H), 3.84 (t, J ¼ 5.5 Hz, 8H), 3.77
(t, J ¼ 6.2 Hz, 4H), 1.58 (dd, J ¼ 18.3, 10.7 Hz, 12H), 1.33
(dd, J ¼ 14.8, 7.5 Hz, 12H), 0.99–0.76 (m, 18H). 13C NMR
(100 MHz, CDCl3) d 150.95, 150.07, 150.04, 132.80, 130.86,
127.80, 127.56, 117.57, 117.28, 116.59, 115.67, 108.29,
106.68, 69.50, 69.37, 39.30, 31.67, 31.64, 31.60, 19.31,
19.23, 13.83. m/z (MALDI-TOF) 950.592; [MþH]þ requires
950.659.
Compound 1h (2.20 g, 2.5 mmol), pyrrole (28 mL, 0.4 mol),
and InCl3 (111 mg, 0.5 mmol) were reacted under an argon
atmosphere at 508C for 30 min. The reaction was quenched with
powdered NaOH (0.8 g, 20 mmol) and stirring for 45 min before
filtering. Excess pyrrole was removed by distillation under
reduced pressure, and the resulting solid was treated with
hexanes (20 mL). The solvent was removed under reduced
pressure. The crude product was purified by column chroma-
tography on silica gel (hexane/CH2Cl2/ethyl acetate ¼ 4 : 2 : 1)
to afford the title compound as a dark green solid (2.71 g, 97 %).
M.p. 124–1268C. 1H NMR (400 MHz, CDCl3) d: 8.24 (brs, 4H),
7.43 (s, 4H), 7.16 (s, 2H), 7.13 (s, 2H), 6.72 (s, 2H), 6.68 (s, 4H),
6.14 (s, 4H), 5.95 (s, 4H), 5.71 (s, 2H), 4.03 (s, 4H), 3.90 (m, 8H),
1.78 (m, 8H), 1.61 (m, 16H), 1.33 (m, 16H), 1.06–0.80 (m, 18H);
13C NMR (100 MHz, CDCl3) d 151.25, 150.81, 132.61, 131.70,
127.66, 127.08, 123.66, 123.48, 116.74, 115.22, 111.30, 110.94,
108.47, 106.80, 69.74, 69.54, 69.50, 39.21, 32.01, 31.72, 29.72,
29.58, 29.45, 26.40, 22.79, 19.61, 19.36, 14.19, 14.09, 13.98;
m/z (MALDI-TOF) 1114.730; [MþH]þ requires 1114.749.
2,5-Bis(octyloxy)-1,4-bis{[(2,5-bis(octyloxy)-4-
(dipyrromethan-5-yl)]phenylenevinylene} benzene (3g)
Compound 1 g (1.02 g, 1.0 mmol), pyrrole (11.2 mL,
160 mmol), and InCl3 (45 mg, 0.2 mmol) were reacted under
an argon atmosphere at 508C for 30 min. The reaction was
quenched with powdered NaOH (0.4 g, 10 mmol) and stirring
for 45 min before filtering. Excess pyrrole was removed by
distillation under reduced pressure, and the resulting solid was
treated with hexanes (20 mL). The solvent was removed under
reduced pressure. The crude product was purified by column
chromatography on silica gel (hexane/CH2Cl2/ethyl acetate ¼
4 : 2 : 1) to afford the title compound as a dark green solid (1.18 g,
4,40-Oxybis(phenyldipyrromethane) (3i)
4,40-Oxydibenzaldehyde (565 mg, 2.5 mmol) was dissolved
in dry pyrrole (28 mL, 0.4 mol) and flushed with argon for
10 min. InCl3 (111 mg, 0.5 mmol) was added, and the reaction
was allowed to proceed for 30 min before quenching with
powdered NaOH (0.8 g, 20 mmol). The mixture was stirred for
45 min and then filtered. Excess pyrrole was removed by
distillation under reduced pressure and the resulting yellow
solid was treated with hexanes (10 mL). The solvent was
removed under reduced pressure, and the residue was purified
by column chromatography on silica gel (eluted with CH2Cl2) to
afford a pale yellow solid (1.04 g, 91 %). M.p. 74–778C.
1H NMR (400 MHz, CDCl3) d 7.95 (brs, 4H), 7.21–7.02
(m, 4H), 6.94 (t, J ¼ 7.9 Hz, 4H), 6.70 (s, 4H), 6.16 (d, J ¼
2.6 Hz, 4H), 5.92 (s, 4H), 5.46 (s, 2H); 13C NMR (100 MHz,
CDCl3) d 155.98, 137.06, 132.53, 129.59, 118.79, 117.25,
108.34, 107.18, 43.20; m/z (MALDI-TOF) 457.189; [MþH]þ
requires 458.210.
1
94 %). M.p. 143–1468C. H NMR (400 MHz, CDCl3) d: 8.25
(s, 4H), 7.42 (s, 4H), 7.16 (s, 2H), 7.13 (s, 2H), 6.72 (s, 2H), 6.68
(s, 4H), 6.14 (d, J ¼ 2.7 Hz, 4H), 5.95 (s, 4H), 5.70 (s, 2H), 4.03
(t, J ¼ 6.2 Hz, 4H), 3.88 (dt, J ¼ 16.2, 5.1 Hz, 8H), 1.91–1.69 (m,
12H), 1.68–1.42 (m, 12H), 1.29 (s, 36H), 0.87 (t, J ¼ 7.1 Hz,
18H). 13C NMR (100 MHz, CDCl3) d 151.34, 150.96, 150.79,
132.59, 131.67, 128.21, 127.12, 123.72, 123.52, 116.69, 115.21,
111.31, 110.98, 108.44, 106.76, 69.85, 69.76, 39.25, 31.97,
31.94, 29.72, 29.26, 29.24, 29.19, 26.35, 26.26, 26.11, 22.73,

Porphyrin Dimers
979
22.71, 14.14. m/z (MALDI-TOF) 1254.805; [MþH]þ requires
Preparation of 5-(4-bromophenyl)dipyrromethane-
1,9-diphenylcarbinol (4) (CAS: 744203–06–3)
1254.806.
A modified literature procedure was used for this reaction.[11]
N-Decyl-3,6-bis(dipyrromethan-5-yl)carbazole (3k)
A
solution of 5-(4-bromophenyl)dipyrromethane (3.01 g,
Compound 1k (910 mg, 2.5 mmol), pyrrole (28 mL, 0.4 mol),
and InCl3 (111 mg, 0.5 mmol) were reacted under an argon
atmosphere at 508C for 30 min. The reaction was quenched with
powdered NaOH (0.8 g, 20 mmol), and stirred for 45 min before
filtering. Excess pyrrole was removed by distilling under
reduced pressure, and the resulting solid was treated with
hexanes (20 mL), which was removed under reduced pressure.
The crude product was purified by column chromatography on
silica gel (hexane/CH2Cl2/ethyl acetate ¼ 4 : 2 : 1) to afford the
title compound as a yellow solid (1.32 g, 89 %). M.p. 109–
1118C; 1H NMR (400 MHz, CDCl3) d 7.93 (s, 4H), 7.82 (s, 2H),
7.31–7.25 (m, 4H), 6.67 (s, 4H), 6.16 (s, 4H), 5.95 (s, 4H), 5.60
(s, 2H), 4.24 (s, 2H), 1.82 (s, 2H), 1.23 (s, 14H), 0.87 (s, 3H).
13C NMR (100 MHz, CDCl3) d 140.23, 133.68, 133.02, 126.78,
123.02, 120.36, 117.39, 109.28, 108.67, 107.37, 44.27, 43.60,
32.16, 29.85, 29.80, 29.72, 29.57, 29.35, 27.63, 22.97, 14.42.
m/z (MALDI-TOF) 595.368; [MþH]þ requires 594.355.
10 mmol) in dry toluene (150 mL) was treated with a EtMgBr
solution (50 mL, 50 mmol, 1.0 M in THF) under argon at room
temperature. After stirring for 60 min, a solution of C6H5COCl
(3.5 mL, 30 mmol) in toluene (15 mL) was added over 15 min.
After stirring for 3 h, the reaction was quenched with saturated
aqueous NH4Cl (80 mL). The solution was then extracted with
ethyl acetate (2 ꢀ 40 mL). The organic phases were combined,
washed with water, brine, and then dried over Na2SO4. After
removing the toluene, the crude product was purified by column
chromatography on silica gel (petroleum ether/CH2Cl2/ethyl
acetate ¼ 4 : 2 : 1) to afford the desired dipyrromethane-
dicarbinol 4 as a brown solid. (1.63 g, 32 %). M.p. 114–1168C.
1H NMR (400 MHz, CDCl3) d 11.36 (s, 2H), 7.74–7.78 (m, 4H),
7.45–7.52 (m, 4H), 7.38–7.45 (m, 6H), 6.58–6.59 (m, 2H), 5.98
(m, 2H), 5.65 (s, 1H); 13C NMR (100 MHz, CDCl3) d 184.64,
140.30, 139.41, 138.16, 131.92, 131.74, 131.17, 130.45, 129.43,
128.08, 121.46, 120.87, 111.19,44.32; m/z (MALDI-TOF)
509.00; [MþH]þ requires 509.39.
N,N-Bis[4-(dipyrromethan-5-yl)phenyl]-4-
bromophenylamine (3l)
General Procedure for the Efficient Synthesis of Novel
Porphyrin Dimers via the Condensation Reaction of Various
Bis(dipyrromethanes) and Dipyrromethanedicarbinol in the
Presence of an InCl3 Catalyst and Mixed-Solvent System
Compound 1l (951 mg, 2.5 mmol), pyrrole (28 mL, 0.4 mol),
and InCl3 (111 mg, 0.5mmol) were reacted under an argon
atmosphere at 508C for 30 min. The reaction was quenched with
powdered NaOH (0.8g, 20mmol) and stirred for 45 min before
filtering. Excess pyrrole was removed by distillation under
reduced pressure, and the resulting solid was treated with hexanes
(20 mL), which was removed under reduced pressure. The crude
product was purified by column chromatography on silica gel
(CH2Cl2/THF¼ 2 : 1) to afford the title compound as a yellow
solid (1.4g, 92%). M.p. 137–1408C; 1H NMR (400 MHz, CDCl3)
d 7.97 (s, 4H), 7.31 (d, J ¼ 8.3 Hz, 2H), 7.09 (d, J ¼ 8.0 Hz, 4H),
6.99 (d, J ¼ 7.7Hz, 4H), 6.93 (d, J ¼ 8.3Hz, 2H), 6.72 (s, 4H),
6.17 (s, 4H), 5.93 (s, 4H), 5.43 (s, 2H). 13C NMR (100 MHz,
CDCl3) d 146.74, 145.96, 136.95, 132.47, 132.13, 129.24, 125.04,
124.28, 117.21, 114.86, 108.40, 107.15, 43.37. m/z (MALDI-
TOF) 611.169; [MþH]þ requires 610.047.
A sample of dipyrromethane-dicarbinol, 4 (crude, 1.1 mmol)
was dissolved in CH2Cl2/CH3CN (200 mL, 19 : 1) and before
addition of bis(dipyrromethane) (0.5 mmol) under argon at room
temperature. After a homogenous solution was obtained, InCl3
(0.221 g, 1 mmol) was added and the reaction mixture was
stirred at room temperature for 0.5 h. Chloranil (615 mg,
2.5 mmol) was then added and the reaction mixture was stirred
for 6 h in air. The resulting mixture was passed through an
alumina column (eluted with CH2Cl2) until the eluent was no
longer dark. The collected eluent was then concentrated. The
resulting crude product was purified by column chromatography
on silica gel (CHCl3/triethylamine ¼ 100 : 1) and recrystallised
from hexanes to afford a purple-black solid.
2,7-Bis[4-(dipyrromethan-5-yl)phenyl]-9,9-
dioctylfluorene (3m)
PDa
Following the general procedure, 3a (255 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
Compound 1m (1.5 g, 2.5 mmol), pyrrole (28 mL, 0.4 mol),
and InCl3 (111 mg, 0.5 mmol) were reacted under an argon
atmosphere at 508C for 30 min. The reaction was quenched with
powdered NaOH (0.8 g, 20 mmol), stirred for 45 min and fil-
tered. Excess pyrrole was removed by distillation under reduced
pressure, and the resulting solid was treated with hexanes
(20 mL), which was removed under reduced pressure. The crude
product was purified by column chromatography on silica gel
(hexane/CH2Cl2/ethyl acetate ¼ 4 : 2 : 1) to afford the title com-
pound 3m as a yellow solid (2.0 g, 96 %). M.p. 121–1258C;
1H NMR (400 MHz, CDCl3) d 8.00 (s, 4H), 7.76 (d, J ¼ 7.7 Hz,
2H), 7.63 (d, J ¼ 7.9 Hz, 4H), 7.60–7.50 (m, 4H), 7.33
(d, J ¼ 7.8 Hz, 4H), 6.73 (s, 4H), 6.19 (d, J ¼ 2.2 Hz, 4H), 5.99
(s, 4H), 5.55 (s, 2H), 2.08–1.96 (m, 4H), 1.27–0.99 (m, 20H),
0.80–0.71 (m, 10H). 13C NMR (100 MHz, CDCl3) d 151.90,
141.25, 140.53, 140.25, 139.75, 132.60, 128.98, 127.53, 126.08,
121.58, 120.16, 117.40, 108.72, 107.47, 55.44, 43.93, 40.56,
31.90, 30.17, 29.32, 24.01, 22.71, 14.15. m/z (MALDI-TOF)
830.529; [MþH]þ requires 830.518.
4
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDa yield was 26 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1), and recrystallised from hexane to
afford a purple-black solid. (131 mg, 18 %). M.p. .2808C.
1H NMR (400 MHz, CDCl3) d 9.33 (s, 4H), 9.03 (s, 4H),
8.85–8.91 (s, 8H), 8.09–8.30 (m, 12H), 8.06 (s, 2H), 7.81–
7.93 (m, 16H), 3.87–3.90 (t, 4H), 0.85–0.98 (s, 4H), 0.39–0.44
(d, 4H), 0.20–0.22 (t, 6H), ꢁ2.62 (s, 4H). m/z (MALDI-TOF)
1453.408; [MþH]þ requires 1453.365; UV-Vis (CHCl3) lmax
:
420, 423(Soret), 514, 548, 587, 645 nm.
PDb
Following the general procedure, 3b (312 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
4

980
H. Zhao et al.
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDb yield was 26 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
a purple-black solid. (149 mg, 19 %). M.p. 146–1508C. 1H NMR
(400 MHz, CDCl3) d 9.33 (s, 4H), 9.03 (s, 4H), 8.86 (m, 8H),
8.32–8.05 (m, 14H), 8.92–7.77 (m, 16H), 3.88 (s, 4H), 0.98 (s,
4H), 0.91–0.77 (m, 4H), 0.66 (m, 4H), 0.58–0.26 (m, 18H),
ꢁ2.63 (s, 4H). m/z (MALDI-TOF) 1566.240; [MþH]þ requires
1565.576; UV-Vis (CHCl3) lmax: 420, 422 (Soret), 515, 551,
588, 645 nm.
m/z (MALDI-TOF) 1673.515; [MþH]þ requires 1673.671;
UV-Vis (CHCl3) lmax: 417, 423 (Soret), 516, 551, 589, 646 nm.
PDf
Following the general procedure, 3f (475 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
4
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDf yield was 26 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
1
a purple-black solid (175 mg, 18 %). M.p. .3008C; H NMR
(400 MHz, CDCl3) d 9.04 (d, J ¼ 4.5 Hz, 4H), 8.87 (d, J ¼
4.7 Hz, 8H), 8.83 (d, J ¼ 4.5 Hz, 4H), 8.24 (s, 8H), 8.11 (dd,
J ¼ 20.5, 7.5 Hz, 4H), 7.91 (d, J ¼ 6.3 Hz, 4H), 7.85–7.71
(m, 12H), 7.49 (d, J ¼ 3.5 Hz, 6H), 4.24 (t, J ¼ 6.3 Hz, 4H), 4.04
(t, J ¼ 6.4 Hz, 4H), 3.87 (t, J ¼ 6.3 Hz, 4H), 1.90 (dd, J ¼ 14.0,
6.5 Hz, 4H), 1.73 (dd, J ¼ 14.2, 6.7 Hz, 4H), 1.64 (dd, J ¼ 14.8,
7.4 Hz, 4H), 1.42 (dd, J ¼ 14.8, 7.4 Hz, 4H), 1.09 (t, J ¼ 7.4 Hz,
6H), 1.01 (dd, J ¼ 14.0, 7.1 Hz, 4H), 0.89 (t, J ¼ 7.3 Hz, 6H),
0.53 (dd, J ¼ 14.8, 7.4 Hz, 4H), 0.25 (t, J ¼ 7.3 Hz, 6H), ꢁ2.71
(s, 4H); m/z (MALDI-TOF) 1893.667; [MþH]þ requires
1893.676; UV-Vis (CHCl3) lmax: 423 (Soret), 516, 552, 590,
645 nm.
PDc
Following the general procedure, 3c (339 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
4
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under argon an atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDc yield was 25 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
a purple-black solid (146 mg, 18 %). M.p. 195–1988C. 1H NMR
(400 MHz, CDCl3) d 9.33 (s, 4H), 9.03 (s, 4H), 8.86 (m, 8H),
8.32–8.05 (m, 14H), 8.92–7.77 (m, 16H), 3.88 (s, 4H), 0.98 (s,
4H), 0.91–0.77 (m, 4H), 0.66 (m, 4H), 0.58–0.26 (m, 26H),
ꢁ2.63 (s, 4H). m/z (MALDI-TOF) 1621.573; [MþH]þ requires
1621.682; UV-Vis (CHCl3) lmax: 420, 422 (Soret), 516, 551,
589, 647 nm.
PDg
Following the general procedure, 3 g (628 mg, 0.5 mmol) and
4
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDg yield was 23 % based on LCMS. The resulting product
was purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
a purple-black solid (176 mg, 16 %). M.p. 208–2118C. 1H NMR
(400 MHz, CDCl3) d 8.96 (d, J ¼ 1.9 Hz, 4H), 8.84 (d, J ¼
12.9Hz, 12H), 8.23 (dd, J ¼ 17.0, 4.6 Hz, 8H), 8.10 (dd, J ¼ 24.0,
6.9 Hz, 4H), 7.88 (d, J ¼ 18.2 Hz, 8H), 7.78 (s, 12H), 7.64
(s, 4H), 7.40 (s, 2H), 4.23 (s, 4H), 4.09 (s, 4H), 3.88 (s, 4H), 2.01
(s, 4H), 1.91 (s, 4H), 1.66 (s, 4H), 1.36 (s, 12H), 1.26 (s, 18H), 0.97
(s, 4H), 0.87 (d, J ¼ 21.5 Hz, 12H), 0.52 (dd, J ¼ 35.4, 6.3 Hz,
8H), 0.32 (d, J ¼ 7.0 Hz, 12H), ꢁ2.75 (s, 4H); m/z (MALDI-
TOF) 2198.987; [MþH]þ requires 2198.531; UV-Vis (CHCl3)
PDd
Following the general procedure, 3d (221 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
4
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDd yield was 24 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
1
a purple-black solid (118 mg, 17 %). M.p. .2808C. H NMR
(400 MHz, CDCl3) d 9.10 (s, 4H), 8.85–8.90 (s, 12H), 8.42 (s,
4H), 8.26 (t, 8H), 8.08–8.14 (s, 4H), 7.92 (s, 4H), 7.71–7.83 (s,
16H), ꢁ2.73 (s, 4H); m/z (MALDI-TOF) 1385.228; [MþH]þ
requires 1385.247; UV-Vis (CHCl3) lmax: 421, 423 (Soret), 516,
552, 590, 646 nm.
l
max: 426 (Soret), 525, 562, 600, 657 nm.
PDh
PDe
Following the general procedure, 3h (558 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
Following the general procedure, 3e (365 mg, 0.5 mmol) and
4
4
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDh yield was 22 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
a purple-black solid (165 mg, 16 %). M.p. 217–2208C. 1H NMR
(400 MHz, CDCl3) d 8.95 (s, 4H), 8.85 (s, 12H), 8.22 (s, 8H),
8.08 (s, 4H), 7.78 (s, 12H), 7.64 (s, 4H), 7.41 (s, 2H), 3.88–4.23
(m, 12H), 1.91–2.01(m, 8H), 1.26–1.66 (m, 18H), 0.87–0.97 (m,
12H), 0.52 (m, 8H), 0.32 (d, J ¼ 7.0 Hz, 12H), ꢁ2.75 (s, 4H); m/z
(MALDI-TOF) 2058.185; [MþH]þ requires 2058.265; UV-Vis
(CHCl3) lmax: 421, 423 (Soret), 515, 552, 588, 647 nm.
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDe yield was 25 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
a purple-black solid (151 mg, 18 %). M.p. 193–1978C. 1H NMR
(400 MHz, CDCl3, TMS) d 9.09 (d, J ¼ 3.8 Hz, 4H), 8.98–8.78
(m, 12H), 8.26 (s, 8H), 8.12 (m, 4H), 7.92 (s, 4H), 7.71–7.81 (m,
16H), 4.16 (t, J ¼ 5.8 Hz, 4H), 3.99 (t, J ¼ 5.9 Hz, 4H), 1.94–
1.79 (m, 4H), 1.66–1.53 (m, 4H), 0.77–1.05 (m, 10H), 0.57 (dd,
J ¼ 14.6, 7.3 Hz, 4H), 0.29 (t, J ¼ 7.2 Hz, 6H), ꢁ2.69 (s, 4H);

Porphyrin Dimers
981
PDi
8.25 (t, J ¼ 7.8 Hz, 12H), 8.10 (d, J ¼ 7.7 Hz, 4H), 7.90 (d,
J ¼ 7.6 Hz, 4H), 7.77 (d, J ¼ 6.4 Hz, 16H), 7.67 (d, J ¼ 8.4 Hz,
2H), 7.60 (d, J ¼ 8.3 Hz, 2H), ꢁ2.76 (s, 4H); m/z (MALDI-TOF)
Following the general procedure, the reaction was conducted
with 3i (229 mg, 0.5 mmol) and 5-(4-bromophenyl)dipyrro-
methane-1,9-diphenylcarbinol 4 (1.1 mmol) in CH2Cl2/ CH3CN
(200 mL, 19 : 1) under argon atmosphere at room temperature.
The formed intermediate was oxidised with Chloranil (615 mg,
2.5 mmol) in the air. The yield of PDi was 25 % on LCMS. The
resulting product was purified by column chromatography on
silica gel (CHCl3/triethylamine ¼ 100 : 1), and was recrystal-
lised from hexane to afford a purple-black solid (126 mg, 18 %).
1555.274; [MþH]þ requires 1555.254; UV-Vis (CHCl3) lmax
:
419, 422 (Soret), 517, 555, 592, 648 nm.
PDm
Following the general procedure, 3m (415 mg, 0.5 mmol)
and 5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol 4
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDm yield was 22 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
1
M.p. 218–2228C. H NMR (400 MHz, CDCl3) d 9.05 (s, 4H),
8.80–8.90 (m, 12H), 8.34 (m, 4H), 8.09–8.22 (m, 12H), 7.90 (m,
6H), 7.78 (s, 8H), 7.44 (s, 8H), ꢁ2.79 (s, 4H); m/z (MALDI-
TOF) 1401.263; [MþH]þ requires 1401.247; UV-Vis (CHCl3)
l
max: 421, 423 (Soret), 515, 550, 589, 646 nm.
1
a purple-black solid (116 mg, 14 %). M.p. .3008C. H NMR
(400 MHz, CDCl3) d 9.01 (d, J ¼ 4.5 Hz, 4H), 8.94–8.86 (m,
8H), 8.84 (d, J ¼ 4.4 Hz, 4H), 8.36 (d, J ¼ 7.8 Hz, 4H), 8.24 (d,
J ¼ 6.1 Hz, 8H), 8.13 (dd, J ¼ 15.3, 8.0 Hz, 8H), 8.05–7.97 (m,
6H), 7.91 (d, J ¼ 8.0 Hz, 4H), 7.79 (d, J ¼ 7.1 Hz, 12H), 2.35–
2.24 (m, 4H), 1.00–0.86 (m, 24H), 0.83 (t, J ¼ 7.3 Hz, 6H),
ꢁ2.75 (s, 4H); m/z (MALDI-TOF) 1662.347; [MþH]þ requires
1662.347; UV-Vis (CHCl3) lmax: 423 (Soret), 516, 552, 590,
646 nm.
PDj
Following the general procedure, 3j (275 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
4
(1.1 mmol) were reacted in CH2Cl2/CH3CN (200 mL, 19 : 1)
under an argon atmosphere at room temperature. The interme-
diate was oxidised by Chloranil (615 mg, 2.5 mmol) in air. The
PDj yield was 26 % based on LCMS. The resulting product was
purified by column chromatography on silica gel (CHCl3/
triethylamine ¼ 100 : 1) and recrystallised from hexane to afford
Supplementary Material
1
a purple-black solid (134 mg, 18 %). M.p. .2808C. H NMR
1H-, 13C NMR spectra for all unknown compounds and UV-Vis
spectra for all porphyrin dimers are available on the Journal’s
website.
(400 MHz, CDCl3) d 8.93 (s, 4H), 8.83–8.87 (m, 12H), 8.21 (s,
8H), 8.09 (m, 4H), 7.78–7.90 (s, 16H), 7.66 (s, 4H), 7.49 (s, 8H),
ꢁ2.78 (s, 4H); m/z (MALDI-TOF) 1493.213; [MþH]þ requires
1493.242; UV-Vis (CHCl3) lmax: 418, 423 (Soret), 514, 550,
588, 646 nm.
Acknowledgements
We are grateful for the financial support of this work from the Natural
Science Foundation of China (No. 21342003, No. 51076032).
PDk
Following the general procedure, 3k (297 mg, 0.5 mmol) and
5-(4-bromophenyl) dipyrromethane-1,9-diphenylcarbinol
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