Bis-porphyrin arrays. Part 3. 1 the synthesis of model bisporphyrin dimers and an electrochemical study

Article abstract of DOI:10.1039/a910323f

We have successfully synthesised exo and endo diphenylacetylene linked bis-porphyrin dimers. We found that the exo-bis-porphyrin dimer could be easily prepared in good yield whilst the endo-dimer was harder to form due to the steric constraints of the wejo-substituents. Electrochemical studies indicated that the porphyrin centred reductions of the bis-porphyrin dimers were dominated by the bis-porphyrin moieties. We found that the first four one-electron reductions of the exo- and endo-bis-porphyrin dimers occurred at similar potentials. Finally, at more negative potentials the bis-porphyrin dimers were reduced further which significantly changed the subsequent oxidation processes. This is thought to be due to a conformational change in the molecule which causes a change in orbital . density in the "excited state". The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/a910323f

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Bis-porphyrin arrays. Part 3.† The synthesis of model bis-
porphyrin dimers and an electrochemical study
Richard Beavington and Paul L. Burn*
1
The Dyson Perrins Laboratory, South Parks Road, Oxford, UK OX1 3QY
Received (in Cambridge, UK) 23rd December 1999, Accepted 2nd February 2000
Published on the Web 31st March 2000
We have successfully synthesised exo and endo diphenylacetylene linked bis-porphyrin dimers. We found that the
exo-bis-porphyrin dimer could be easily prepared in good yield whilst the endo-dimer was harder to form due to the
steric constraints of the meso-substituents. Electrochemical studies indicated that the porphyrin centred reductions
of the bis-porphyrin dimers were dominated by the bis-porphyrin moieties. We found that the first four one-electron
reductions of the exo- and endo-bis-porphyrin dimers occurred at similar potentials. Finally, at more negative
potentials the bis-porphyrin dimers were reduced further which significantly changed the subsequent oxidation
processes. This is thought to be due to a conformational change in the molecule which causes a change in orbital
density in the “excited state”.
Introduction
base bis-porphyrin was not high. Therefore, in this study we
chose to use nickel instead of copper, as nickel porphyrins also
tend to be less polar than their free-base counterparts. As nickel
is diamagnetic the products can be easily analysed by NMR
spectroscopy. The second change to our reported route was to
replace the bromophenyl derivative with the iodophenyl group
to allow for efficient palladium catalysed couplings.
1
Porphyrin arrays have been assembled using covalent bonds
2
and metal complexation. Porphyrin arrays in which the por-
phyrins are connected via conjugated bridges have tended to use
either meso- or β-pyrrolic linking points. We have been work-
ing towards a new class of porphyrin array in which both the
β-pyrrolic and meso-positions on a single porphyrin are utilised.
In particular, our aim was to link bis-porphyrins where the
two porphyrins are joined at the β-pyrrolic position with a
tetraazaanthracene bridge. Such bis-porphyrin arrays are of
interest as charge transport layers in light-emitting diodes or as
materials for photovoltaics because the joining of the bis-
porphyrins should alter their processing properties and, if a
conjugated link is used, the electronic properties of the bis-
porphyrins may also be modulated. We chose a diphenyl-
acetylene link as this has been successfully used in simple
The method of porphyrin-α-dione synthesis provided
two possible mono(4Ј-iodophenyl)porphyrin-α-diones, (exo)
(
Scheme 1) or (endo) (Scheme 2), in which the iodophenyl is
5
away from or flanking the porphyrin-α-dione respectively.
These two porphyrin-α-diones could in turn give rise to bis-
porphyrins with distinctly different geometries.
The mono(4Ј-iodophenyl)porphyrin-α-diones were more
polar than the symmetric porphyrin-α-dione 2. Therefore, for
ease of separation of the bis-porphyrins 5 and 9 the symmetric
nickel chelated porphyrin-α-dione 3 was required. Nickel
porphyrin-α-dione 3 was made in an 86% yield by heating at
3
porphyrin systems. To prepare meso-connected bis-porphyrin
dimers with a phenylacetylene bridge it was necessary to make
bis-porphyrins which were functionalised at a meso-position.
To this end, we have reported the synthesis of bis-porphyrins
with a single meso-halophenyl moiety, which could be used in
palladium catalysed couplings, with the other meso-positions
6
reflux a solution of the free-base porphyrin-α-dione 2 and
excess nickel acetate tetrahydrate in DMF for 0.5 hours.
The synthesis of the mononickel exo-(4Ј-iodophenyl)bis-
porphyrin 5 was achieved by reacting a solution of the exo-
(
4Ј-iodophenyl)porphyrin-α-dione 1 with a small excess of
4
carrying solubilising 3,5-di-tert-butylphenyl groups. In this
benzene-1,2,4,5-tetraamine tetrahydrochloride in pyridine
heated at reflux for 1 h. The porphyrin diamino-quinoxaline
intermediate was then condensed with the nickel porphyrin-α-
dione 3 by heating the reaction mixture at reflux for a further 16
hours. Purification was straightforward, and the mononickel
exo-(4Ј-iodophenyl)bis-porphyrin 5 was isolated in an 81%
yield. The dinickel bis-porphyrin 4 and free-base bis(4Ј-
iodophenyl)bis-porphyrin 6 were isolated in 9 and 7% yields
respectively. In addition, the excess of nickel porphyrin-α-dione
paper we describe the preparation of two isomeric bis-
porphyrin dimers and present a preliminary study on their
redox properties.
Results and discussion
In our report on the synthesis of asymmetric bis-porphyrins
one of the problems was the separation of the desired
asymmetric bis-porphyrin from symmetric bis-porphyrin by-
3
6
was returned. There are two possible isomers of bis-porphyrin
, the trans-isomer as illustrated in Scheme 1 and the cis-isomer
4
products of similar polarity. Separation was achieved by chel-
ating copper into the less polar porphyrin-α-dione which gave
bis-porphyrins with zero, one or two metals chelated. The three
bis-porphyrins could then be easily separated by chromato-
graphy over silica as the chelated metal atoms enhanced the
difference in polarity of the bis-porphyrins. However, one of
the difficulties encountered in that work was that, although the
copper could be removed, the yield of the corresponding free-
which has the 4Ј-iodophenyl groups on the same side of the bis-
porphyrin. There is no reactivity difference which would mark
out either isomer as the favoured product, however we believe
that we only formed and isolated the trans-isomer. Evidence for
1
this comes from the H NMR of 5 and 6. The bridge protons of
5
are observed as two singlets at 8.57 and 8.65 ppm respectively.
If 6 was the cis-isomer then we would also expect to see two
singlets for the bridge protons, but instead, we only see one
1
†
For Part 2, see ref. 4.
singlet in the H NMR. Although this is consistent with the C
2
DOI: 10.1039/a910323f
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Scheme 1 Reagents and conditions: i, Ni(OAc) ؒ4H O, DMF, ∆; ii, pyridine, benzene-1,2,4,5-tetraamine tetrahydrochloride, Ar, ∆ then second
2
2
porphyrin-α-dione, Ar, ∆; iii, bis(tri-n-butylstannyl)acetylene, Pd(OAc) , PPh , Et N, ∆.
2
3
3
symmetry of the illustrated trans-isomer, we do not know why it
is the only isomer isolated.
bis-porphyrin 4 in a 10% yield, and the free-base bis(iodo-
phenyl)bis-porphyrin 10 in a 41% yield. The excess nickel
porphyrin-α-dione 3 was returned. Unlike the free-base exo-
bis(4Ј-iodophenyl)bis-porphyrin 6 the free-base endo-bis(4Ј-
iodophenyl)bis-porphyrin 10 was isolated as a 1:1 mixture of
The alternative endo-isomer, the mononickel (4Ј-iodophenyl)-
bis-porphyrin 9, was prepared by a similar method. A solution
of the free-base endo-(4Ј-iodophenyl)porphyrin-α-dione 8 and
a small excess of benzene-1,2,4,5-tetraamine tetrahydrochloride
in pyridine was heated at reflux for 1 h. The porphyrin diamino-
quinoxaline intermediate was then condensed with nickel
porphyrin-α-dione 3 under the same conditions but for 9.5
hours. Purification was again straightforward, giving the mono-
nickel iodophenylbis-porphyrin 9 in a 43% yield, the dinickel
1
the cis- and trans-isomers. This was clearly seen by H NMR
where there were overlapping sets of absorptions of the cis- and
trans-isomers. The ratio could be determined from the clearly
differentiated signals assigned to the protons of one half of the
4Ј-iodophenyl AAЈBBЈ system for each isomer which were at
8.27 and 8.34 ppm. It might have been thought that in this case
1
232
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Scheme 2 Reagents and conditions: i, pyridine, benzene-1,2,4,5-tetraamine tetrahydrochloride, Ar, ∆ then second porphyrin-α-dione, Ar, ∆; ii,
bis(tri-n-butylstannyl)acetylene, Pd(OAc) , PPh , Et N, ∆.
2
3
3
there would be different steric demands on the formation of the
two isomers, but that appears from this result not to be the case.
The relatively high yield of 10 compared with 6, where the
overall steric demand of two iodophenyl and two 3,5-di-tert-
butylphenyl groups in 10 would be less than that for four 3,5-
di-tert-butylphenyl groups in 6, is consistent with the results
showing that less sterically demanding porphyrin-α-diones,
when used in the first condensation step, give less of the desired
asymmetric bis-porphyrin.
7
The final step in the synthesis of the two bis-porphyrin arrays
illustrated in Schemes 1 and 2 was to join the bis-porphyrins
together using palladium catalysed Stille couplings. The
coupling of the exo-(4Ј-iodophenyl)bis-porphyrin 5 to form the
exo-bis-porphyrin dimer was achieved by reaction with bis-
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Scheme 3 Reagents and conditions: i, bis(tri-n-butylstannyl)acetylene, Pd(OAc) , PPh , Et N, ∆.
2
3
3
(
tri-n-butylstannyl)acetylene, in the presence of palladium()
All the porphyrin dimers produced were highly soluble in
chloroform and dichloromethane which suggests that extending
the dimers to polymers may give rise to materials which are
solution processible.
acetate and triphenylphosphine in triethylamine heated at
reflux for 3 hours. On purification the exo-bis-porphyrin dimer
7
was isolated in a 76% yield. The structure of 7 was confirmed
by its MALDI mass spectra, which showed an isotopic distribu-
tion of molecular ions which corresponded well to the calcu-
lated distribution for the molecular formula of 7. In addition,
Electronic properties
1
the H NMR of 7, although complicated, was consistent with
We have carried out an initial study on the electronic properties
of the bis-porphyrin dimers using cyclic voltammetry. These
bis-porphyrin dimers can be considered to consist of two
porphyrin chromophores; namely a tetraazaanthracene bridged
bis-porphyrin which comprises one nickel and one free-base
porphyrin, and a meso-diphenylacetylene linked porphyrin
dimer containing two free-base porphyrins. Electrochemical
studies on both these systems have been reported. Porphyrins
normally undergo two one-electron reductions (to form a rad-
ical anion and then a dianion) and two one-electron oxidations
(to form a radical cation and subsequently a dication). If two
porphyrins within a porphyrin array are in electronic communi-
cation then the reduction or oxidation of one porphyrin ring
can affect the redox properties of the second porphyrin ring. In
our case two one-electron reductions are clearly observed for
the single porphyrin 14 (Fig. 1a). However, for bis-porphyrin 15
four quasi-reversible one-electron porphyrin centred reductions
the C symmetry of the molecule.
2
By using the endo-(4Ј-iodophenyl)bis-porphyrin 9 it was pos-
sible to make a similar endo-bis-porphyrin dimer 11. The bis-
porphyrin 9 was reacted under the same conditions used for the
preparation of 7 and this gave 11 in a 10% yield. We believe that
the low yield of 11 compared to that of 7 is due to the steric
hindrance in the approach of the two endo-bis-porphyrins
in the coupling reaction. The (4Ј-iodophenyl)bis-porphyrin 9
was returned in an 11% yield. As in the case of the exo-bis-
porphyrin dimer 7, the MALDI mass spectrum of 11 showed
an isotopic distribution of molecular ions consistent with the
molecular formula and as expected this corresponded to that
1
observed for 7. The H NMR was also consistent with the
symmetry of 11.
The final porphyrin dimer required in this study was 13
Scheme 3) which was to be used as a model for the electro-
(
8
chemical studies of the diphenylacetylene bridged porphyrins in
the bis-porphyrin dimers. Dimer 13 was prepared by reacting
free-base iodophenylporphyrin 12 with bis(tri-n-butylstannyl)-
acetylene in the presence of a palladium() acetate–triphenyl-
phosphine catalyst in triethylamine heated at reflux for 3 hours.
Under these conditions the free-base porphyrin dimer 13 was
formed in a yield of 84%.
are observed (Fig. 1b). This suggests that there is moderate
electronic communication between the two porphyrin rings in
the bis-porphyrin. In addition, there is a further reduction at a
more negative potential which at first sight appears to be only
partially chemically reversible (Fig. 1c) as the oxidation of the
reduced species has a smaller current than the reduction. How-
ever, in conjunction with this extra reduction the oxidation
1
234
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Table 1 Reduction potentials found in cyclic voltammetry studies
a
b
c
d
Comp.
Conc./mM
Type
E /V
pa
E /V
pc
E1/2/V
1
1
1
1
4
2
6
5
1.1
r1
r2
r1
r2
r1
r2
r1
r2
r3
r4
r5
r1
r2
r3
r4
r5
r1
r2
r3
r4
r5
r6
r1
r2
r3
r4
r1
r2
r3
r4
r5
r6
Ϫ1.59
Ϫ1.95
Ϫ1.58
Ϫ1.92
Ϫ1.68
Ϫ2.17
Ϫ1.24
Ϫ1.43
Ϫ1.68
Ϫ1.90
—
Ϫ1.16
Ϫ1.43
Ϫ1.74
Ϫ2.07
—
Ϫ1.14
Ϫ1.42
Ϫ1.74
Ϫ2.10
Ϫ2.47
—
Ϫ1.55
Ϫ1.90
Ϫ2.46
—
Ϫ1.86
Ϫ2.21
Ϫ1.81
Ϫ2.16
Ϫ1.88
Ϫ2.38
Ϫ1.45
Ϫ1.70
Ϫ1.85
Ϫ2.08
Ϫ2.67
Ϫ1.39
Ϫ1.72
Ϫ1.94
Ϫ2.25
Ϫ2.74
Ϫ1.42
Ϫ1.74
Ϫ1.96
Ϫ2.30
Ϫ2.68
Ϫ2.89
Ϫ1.80
Ϫ2.15
Ϫ2.68
Ϫ2.87
Ϫ1.36
Ϫ1.66
Ϫ1.92
Ϫ2.25
Ϫ2.73
Ϫ2.93
Ϫ1.73
Ϫ2.08
Ϫ1.70
Ϫ2.04
Ϫ1.78
Ϫ2.28
Ϫ1.35
Ϫ1.56
Ϫ1.77
Ϫ1.99
—
Ϫ1.28
Ϫ1.58
Ϫ1.84
Ϫ2.16
—
Ϫ1.28
Ϫ1.58
Ϫ1.85
Ϫ2.20
Ϫ2.58
—
Ϫ1.68
Ϫ2.03
Ϫ2.57
—
0.46
0.53
0.43
7
1
0.34
0.15
1
1
3
5
0.47
0.34
Ϫ1.21
Ϫ1.49
Ϫ1.75
Ϫ2.08
Ϫ2.48
Ϫ1.29
Ϫ1.58
Ϫ1.84
Ϫ2.17
Ϫ2.61
—
a
c
Ϫ1 b
Scan rate = 500 mV s
. r1 First reduction; r2 second reduction, etc.
d
Epa Peak anodic potential. Epc Peak cathodic potential
the orbital energies. A similar argument could be used to
explain the minor changes in the cyclic voltammogram for 15
after the fifth reduction. This would be consistent with work
on diphenylacetylene porphyrin arrays which suggests that a
conformational change could explain enhanced conjugation
observed between the π-electron systems of the porphyrin rings
9
and the bridging diphenylacetylene group in the excited state.
It may be that a similar change occurs after the fourth reduction
of our diphenylacetylene linked dimer.
Fig. 1 Cyclic voltammograms of 14 (a), and 15 (b) and (c).
Given that the bis-porphyrin dimers have nickel chelated into
two of the constituent porphyrin rings, the next step in the
study was to determine the effect of nickel on the porphyrin
redox processes. The model compound we chose to use was exo-
bis-porphyrin 5. The 4-iodophenyl group was found to have no
effect on the porphyrin reduction potentials with 14 and 12
having essentially the same reduction potentials. In contrast,
chelation of nickel to 12, giving 16, moved the two porphyrin
reductions to slightly more negative potentials and increased
the separation between the potentials of the two reductions
(Table 1). The second reduction appears to be less chemically
reversible as its corresponding oxidation peak on the return
sweep of potential is significantly smaller than the reduction
peaks of the one-electron reductions appear to change their
relative intensities. The chemical reversibility of the five reduc-
tion processes was confirmed by multiple scans which showed
no diminution in the current. In contrast, neither 14 nor 15 had
chemically reversible oxidations under the conditions we used.
The oxidative electrochemistry of a porphyrin dimer similar
to 13 with mesitylene as opposed to 3,5-di-tert-butylphenyl
9
meso-substituents has been reported. The porphyrin dimer was
shown to have two two-electron oxidations indicating that the
two porphyrins with the diphenylacetylene bridge were not in
electronic communication. We have studied the reduction pro-
cesses of 13 and found that on reduction the porphyrin dimer
shows two two-electron quasi-reversible porphyrin centred
reductions which are at similar potentials (Table 1) to the single
porphyrin. This indicates that up to the tetraanion there is no
communication between the two porphyrin rings (Fig. 2a).
Ϫ1
peak at 500 mV s . This was confirmed by using a faster
Ϫ1
scan rate (2000 mV s ) and under these conditions the
oxidation of the reduced species became chemically reversible.
The nickel porphyrin 16 also had a chemically reversible
oxidation.
However, when more negative potentials were used, E = Ϫ3.2
The mononickel bis-porphyrin 5 was found to have four
chemically reversible one-electron reductions of the porphyrin
λ
V, then the reduction processes become more complex with two
further reversible reductions observed (Epc (r3) = Ϫ2.68 V and
Epc (r4) = Ϫ2.87 V) and the oxidations on the return sweep of
potential are changed dramatically (Fig. 2b). This may be due
to the structure of the porphyrin dimer rearranging to form an
extended planar π-system over the two porphyrin rings to
accommodate the extra electrons, which in turn would change
rings (Fig. 3a). The reduction couples for 5 (∆E = 290 mV
1,2
Ϫ1
and ∆E3,4 = 330 mV; scan rate: 500 mV s ) are more widely
separated than in the case of the free-base bis-porphyrin
15 (∆E1,2 = 210 mV and ∆E3,4 = 220 mV) with the larger
separations indicating stronger electronic coupling between the
porphyrin rings. When the switching potential was lowered to
J. Chem. Soc., Perkin Trans. 1, 2000, 1231–1240
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E = Ϫ3.6 V (Fig. 3b) two further reductions were seen (E
density than would be expected for removal of a single electron,
λ
pc
(
r5) = Ϫ2.73 and Epc (r6) = Ϫ2.93 V) and the oxidations of
which again suggests that the reduced species may be undergo-
ing a change in electronic structure as discussed for 13 and 15.
In addition, mononickel bis-porphyrin 5 has one partially
chemically reversible oxidation.
the reduced species on the return sweep of potential are quite
different from those observed when E = Ϫ2.6 V (Fig. 3a). In
λ
particular, the oxidation at Epa = Ϫ1.2 V has more current
Fig. 2 Cyclic voltammograms of 13 (a) and (b).
Fig. 3 Cyclic voltammograms of 5 (a) and (b).
1
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at the same potentials as 5 (Table 1). However, unlike bis-
porphyrin 5, which shows two further reductions at more
negative potentials, the exo-bis-porphyrin dimer 7 shows only
one further broad reduction peak (E = Ϫ2.74 V) (Fig. 4b)
pc
reminiscent of the free-base porphyrin 15. In contrast, the
endo-bis-porphyrin dimer 11 shows two further reductions (Fig.
5
b), as observed in the mononickel bis-porphyrin 5 (Fig. 3b).
These results show that there was only a minor effect in having
the two bis-porphyrins covalently linked on the electrochemical
properties and only when very negative switching potentials
were used.
Conclusions
We have successfully synthesised exo and endo diphenylacetyl-
ene linked bis-porphyrin dimers. We found that the exo-bis-
porphyrin dimer could be formed easily and in good yield
whilst the endo-dimer was harder to form due to the steric con-
straints of the meso-substituents. The two bis-porphyrin dimers
were found to have good solubility. The electrochemical studies
indicated that the porphyrin centred redox properties of the
dimers were dominated by the bis-porphyrin moieties. We
found that the redox properties of both exo- and endo-dimers
were essentially the same at low switching potentials. Finally,
at more negative potentials the cyclic voltammograms of the
porphyrin dimers, bis-porphyrins, and bis-porphyrin arrays
showed further reductions which disrupt the oxidation pattern
on the return sweep of potential. This was thought to be due to
conformational changes in the molecule.
Fig. 4 Cyclic voltammograms of 7 (a) and (b).
Experimental
Measurements
1
H NMR spectra were recorded on a Bruker AM-500 (500
MHz) or a Varian Gemini 200 (200 MHz) spectrometer. Infra-
red spectra were recorded using KBr discs with either a Perkin-
Elmer 781 or Paragon 1000 infrared spectrometer. UV-visible
spectra were recorded on Perkin-Elmer UV-visible spectro-
meters (Lambda 2 or Lambda 14P) in either spectrophoto-
metric grade chloroform or dichloromethane. For the free-base
porphyrins the dichloromethane was filtered through a plug of
potassium carbonate immediately before use. The absorption
spectra of the porphyrin-α-diones all had a broad absorption,
relative to the other absorption peaks, at long wavelengths.
The absorption whilst broad often showed a number of minor
3
Ϫ1
Ϫ1
features. ε values are given in dm mol cm . Fast atom
bombardment (FAB) mass spectra (m/z) were recorded on a VG
Autospec spectrometer. Atmospheric pressure chemical ioniz-
ation (APCI) mass spectra were recorded on a VG Platform
spectrometer. Major peaks are listed with intensities quoted
as percentages of the base peak. Due to the combination of
metal chelation, halogen substituents, and size of molecules the
molecular weight observed by mass spectroscopy generally
appeared as a complex isotopic cluster around the expected
parent ion. In these cases we have quoted the most abundant
peak for each compound. Melting points were determined on a
Gallenkamp melting point apparatus and are uncorrected. We
found that although the compounds did not melt, some par-
tially decomposed on heating. This was observable by analysis
with thin-layer chromatography which showed the presence
of more than one compound after heating. Therefore, these
melting points are quoted as decomposition below the highest
temperature measured. Microanalyses were performed in either
the Dyson Perrins Laboratory or the Inorganic Chemistry
Laboratory, Oxford. All solvents for recrystallization were dis-
tilled before use. Dichloromethane and dimethyl sulfoxide were
dried over calcium hydride and freshly distilled before use.
Tetrahydrofuran was dried over sodium wire and freshly
distilled before use. Light petroleum refers to the fraction of
Fig. 5 Cyclic voltammograms of 11 (a) and (b).
From the results observed for 5 and 13 we might expect that
the electrochemistry of bis-porphyrin dimers 7 (exo) and 11
endo) should be the same as that of the mono-nickel bis-
porphyrin 5 at low switching potentials as there is no electronic
through-bond communication between the two porphyrin rings
across the diphenylacetylene bridge. When 7 and 11 were stud-
ied at a low switching potential they were found to have four
chemically reversible two-electron reductions (Figs. 4a and 5a)
(
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boiling point 60–80 ЊC and ether refers to diethyl ether. Thin
layer chromatography was performed on glass micro plates
coated with silica GF254, or with Merck aluminium plates coat-
ed with silica gel 60 F254. Preparative layer chromatography was
performed using glass plates coated with silica gel GF254 with a
concentration band. Column chromatography was performed
using silica gel (flash) C60, 40–60. Where solvent mixtures are
used, the proportions are given by volume. Electrochemistry
was performed using an EG&G Princeton Applied Research
potentiostat/galvanostat model 263A. All measurements were
made at room temperature on samples dissolved in freshly
distilled tetrahydrofuran, with 0.1 M tetra-n-butylammonium
tetrafluoroborate as the electrolyte. The tetrahydrofuran was
distilled from sodium wire and benzophenone under nitrogen,
and then distilled from lithium aluminium hydride under argon.
The electrolyte was purified by recrystallisation from an ethyl
acetate–ether mixture, dried under vacuum, and stored over
P O . The solutions were deoxygenated with argon. A glassy
9%), mp >300 ЊC [Found: C, 79.67; H, 7.33; N, 6.91; m/z
(MALDI) 2367.4 (100%). C158H182N Ni requires C, 80.19; H,
12
2
7.75; N, 7.10%; M, 2366.6]; λmax(CH Cl )/nm (log ε) 428 (5.36),
2
2
450 (5.36), 514sh (4.82), 534 (4.86), and 666 (4.36); δ (500
H
MHz; CDCl ) 1.47 and 1.48 (144 H, 2 × s, t-butyl H), 7.70 (4 H,
3
dd, J2Ј,4Ј = J6Ј,4Ј = 2.0 Hz, C(4Ј) H), 7.73 (8 H, d, J4Ј,2Ј = J4Ј,6Ј = 2.0
Hz, C(2Ј) H and C(6Ј) H), 7.82 (12 H, m, C(4Ј), C(2Ј) H and
C(6Ј) H), 8.56 (2 H, s, bridge H), 8.61 (4 H, s, C(4) H, β-pyrrolic
H), and 8.63 and 8.68 (8 H, ABq, JAB = 5.0 Hz, β-pyrrolic
H). exo-(4Ј-Iodophenyl)heptakis(3Љ,5Љ-di-tert-butylphenyl)bis-
porphyrin nickel() 5 was isolated as a brown solid (188 mg,
81%), mp >300 ЊC [Found: C, 77.49; H, 7.19; N, 7.03; m/z
(FAB) 2323.9 (100%). C150H167N INi requires C, 77.54; H,
12
Ϫ1
7.24; N, 7.23%; M, 2323.6]; νmax(CHCl )/cm 3357 (N-H);
3
λmax(CHCl )/nm (log ε) 428 (5.50), 450sh (5.39), 501 (4.91),
3
612sh (4.28), 641 (4.38), and 686sh (4.09); δ (500 MHz; CDCl )
H
3
Ϫ2.38 (1 H, s, NH), Ϫ2.36 (1 H, s, NH), 1.47–1.57 (126 H, t-
butyl H), 7.71 (2 H, dd, J2Љ,4Љ = J6Љ,4Љ = 2.0 Hz, C(4Љ) H), 7.77 (4
H, br s, C(2Љ) H and C(6Љ) H), 7.83 (1 H, dd, J2Љ,4Љ = J6Љ,4Љ = 2.0
Hz, C(4Љ) H), 7.84 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and
C(6Љ) H), 7.87 (2 H, br m, C(4Љ) H), 7.96–7.97 (2 H, m, C(4Љ) H),
8.00 and 8.13 (4 H, AAЈBBЈ, C(2Ј) H, C(3Ј) H, C(5Ј) H, and
C(6Ј) H), 8.07 (2 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ)
H), 8.08 (2 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ) H),
8.10 (2 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ) H), 8.57
(1 H, bridge H), 8.62 (2 H, s, β-pyrrolic H), 8.65 (1 H, bridge
H), 8.67–8.71 (5 H, 5 × ¹ABq, β-pyrrolic H), 8.77 (1 H, ¹ABq,
2
5
carbon working electrode, platinum wire counter electrode,
and Ag/AgCl/NaCl (sat) reference electrode were used. The
10
ferricenium/ferrocene couple was used as standard, and the
ferrocene was purified by recrystallisation from ethanol and
then dried under vacuum and stored over P O . All the electro-
2
5
Ϫ1
chemical experiments were carried out at 500 mV s unless
stated otherwise. In all cases three cycles were run except for
Figs. 1a and 3a where five were run. In all cases the final cycle is
illustrated in the Figure.
¯
¯
²
²
JAB = 4.5 Hz, β-pyrrolic H), 8.88 (3 H, br ¹ABq and br s,
¯
²
[
2,3-Dioxo-5,10,15,20-tetrakis(3Љ,5Љ-di-tert-butylphenyl)-
β-pyrrolic H), and 8.97 (1 H, ¹ABq, J = 5.0 Hz, β-pyrrolic H).
trans,exo-Bis(4Ј-iodophenyl)hexakis(3Љ,5Љ-di-tert-butylphenyl)-
bis-porphyrin 6 was isolated as a brown solid (8 mg, 7%),
AB
¯
²
chlorinato]nickel(II) 3
A mixture of free-base porphyrin-α-dione 2 (420 mg, 0.384
mmol) and nickel() acetate tetrahydrate (344 mg, 1.38 mmol)
Ϫ1
νmax(KBr disc)/cm 3360 (N-H); λmax(CH Cl )/nm (log ε) 426
2
2
(
(
5.49), 457 (5.43), 500sh (4.87), 603sh (4.22), 615sh (4.26), 628
3
in N,N-dimethylformamide (30 cm ) was heated at reflux for 30
4.29), and 676 (3.83); δ (500 MHz; CDCl ) Ϫ2.39 (2 H, s,
3
H
3
min and allowed to cool. Water (30 cm ) was added to precipi-
NH), Ϫ2.38 (2 H, s, NH), 1.55–1.60 (108 H, 3 × s, t-butyl H),
.83 (2 H, dd, J2Љ,4Љ = J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 8.00 and 8.13 (8 H,
tate the product, which was collected by filtration and washed
with methanol. The filtrate was also collected, the solvent com-
pletely removed, and the residue purified by column chromato-
graphy over silica using a dichloromethane–light petroleum
mixture (2:3) as eluent. Dione 3 was isolated as a green solid
7
AAЈBBЈ, C(2Ј) H, C(3Ј) H, C(5Ј) H, and C(6Ј) H), 8.01 (4 H, m,
C(4Љ) H), 8.09–8.10 (12 H, m, C(2Љ) H and C(6Љ) H), 8.58 (2 H,
s, bridge H), 8.69 and 8.77 (4 H, ABq, JAB = 4.5 Hz, β-pyrrolic
H), 8.89 (4 H, br s, β-pyrrolic H), and 8.91 and 8.98 (4 H, br ABq,
JAB = 5.0 Hz, β-pyrrolic H) [Found: m/z (FAB) 2281.7 (100%).
C142H152N I requires M, 2280.7]. Dione 3 was isolated as a
(
382 mg, 86%), mp >300 ЊC [Found: C, 78.98; H, 8.07;
N, 4.88; m/z (FAB) 1150.7 (100%). C H N O Ni requires C,
7
6
90
4
2
Ϫ1
12 2
7
9.36; H, 7.89; N, 4.87%; M, 1150.3]; νmax(KBr disc)/cm 1723
green solid (69 mg, 35%), which co-chromatographed with and
(
(
C᎐O); λ (CH Cl )/nm (log ε) 415 (4.97), 487 (4.31), and 717
᎐
max
2
2
1
had an identical H NMR spectrum to an authentic sample.
3.71); δ (500 MHz; CDCl ) 1.38 and 1.43 (72 H, 2 × s, t-butyl
H
3
H), 7.35 (4 H, d, J4Ј,2Ј = J4Ј,6Ј = 2.0 Hz, C(2Ј) H and C(6Ј) H),
7
.58 (2 H, dd, J2Ј,4Ј = J6Ј,4Ј = 2.0 Hz, C(4Ј) H), 7.67 (2 H, dd,
endo-(4Ј-Iodophenyl)heptakis(3Љ,5Љ-di-tert-butylphenyl)bis-
J2Ј,4Ј = J6Ј,4Ј = 2.0 Hz, C(4Ј) H), 7.69 (4 H, d, J4Ј,2Ј = J4Ј,6Ј = 1.79
Hz, C(2Ј) H and C(6Ј) H), 8.21 and 8.40 (4 H, ABq, JAB = 5.0
Hz, C(2) H, C(3) H, C(12) H, and C(13) H), and 8.26 (2 H, s,
C(7) H and C(8) H).
porphyrin nickel(II) 9
A solution of endo-(4Ј-iodophenyl)porphyrin-α-dione 8 (50 mg,
0
.045 mmol) and benzene-1,2,4,5-tetraamine tetrahydrochlor-
3
ide (16 mg, 0.056 mmol) in dry, deoxygenated pyridine (1.2 cm )
was heated at reflux under argon for 1 h. The solution was then
transferred under argon to a flask containing 3 (89 mg, 0.077
exo-(4Ј-Iodophenyl)heptakis(3Љ,5Љ-di-tert-butylphenyl)bis-
porphyrin nickel(II) 5
3
mmol). The original flask was rinsed with pyridine (1.5 cm )
A solution of exo-(4Ј-iodophenyl)porphyrin-α-dione 1 (111 mg,
which was then transferred to the reaction mixture under
argon. The reaction mixture was then heated at reflux under
argon for a further 9.5 h and allowed to cool. Dichloromethane
0
.100 mmol) and benzene-1,2,4,5-tetraamine tetrahydrochlor-
3
ide (34 mg, 0.12 mmol) in dry, deoxygenated pyridine (2.7 cm )
was heated at reflux under argon for 1 h. The solution was then
transferred under argon to a flask containing 3 (197 mg, 0.171
mmol). The first reaction flask was rinsed with pyridine (1.5
3
(25 cm ) was added, and the organic solution was washed with
3
3
dilute hydrochloric acid (3 M, 2 × 25 cm ), water (50 cm ),
3
3
sodium bicarbonate solution (5%, 50 cm ), and water (50 cm ),
dried over anhydrous sodium sulfate, filtered, and the solvent
completely removed. The residue was purified by column
chromatography over silica using a dichloromethane–light
petroleum mixture (1:4 to 2:3) as eluent and four bands
were collected. Octakis(3Ј,5Ј-di-tert-butylphenyl)bis-porphyrin
dinickel() 4 was isolated as a brown solid (9 mg, 10%), which
3
cm ) and this was transferred to the reaction mixture under
argon. The reaction mixture was then heated at reflux under
argon for a further 16 h and allowed to cool. Dichloromethane
3
(
(
25 cm ) was added, and the solution was washed with water
3
3 × 25 cm ), dried over anhydrous sodium sulfate, filtered, and
the solvent completely removed. The residue was purified by
column chromatography over silica using a dichloromethane–
light petroleum mixture (1:4 to 1.5:3.5) as eluent and four
bands were collected. Octakis(3Ј,5Ј-di-tert-butylphenyl)bis-
porphyrin dinickel() 4 was isolated as a brown solid (19 mg,
1
co-chromatographed with and had an identical H NMR spec-
trum to an authentic sample. endo-(4Ј-Iodophenyl)heptakis-
(3Љ,5Љ-di-tert-butylphenyl)bis-porphyrin nickel() 9 was isolated
as a brown solid (47 mg, 43%), mp >300 ЊC [Found: C, 77.67;
1
238
J. Chem. Soc., Perkin Trans. 1, 2000, 1231–1240

View Article Online
H, 7.62; N, 6.70; m/z (FAB) 2324.0 (100%). C150H167N INi
bis(tri-n-butylstannyl)acetylene (6.4 mg, 0.011 mmol) in tri-
ethylamine (5.0 cm ) was deoxygenated with argon for 15 min
12
3
requires C, 77.54; H, 7.24; N, 7.23%; M, 2323.6]; ν (CHCl )/
max
3
Ϫ1
cm 3356 (N-H); λmax(CH Cl )/nm (log ε) 426 (5.43), 451
and then heated at reflux for 3 h. The solvent was removed and
the residue was purified by column chromatography over silica
using a dichloromethane–light petroleum mixture (1:4 to
1.5:3.5) as eluent. The main band was collected and the solvent
completely removed to give 7 as a brown solid (36 mg, 76%). A
sample for analysis was recrystallised from a dichloromethane–
methanol mixture, decomp. <300 ЊC [Found: C, 81.51; H, 7.37;
N, 7.58; m/z (MALDI) 4418.1 (100%). C302H334N Ni requires
2
2
(
5.33), 509 (4.83), 606sh (4.18), 642 (4.28), and 692sh (4.03);
δ (500 MHz; CDCl ) Ϫ2.33 (2 H, br s, NH), 1.47–1.61 (126 H,
H
3
7
× s, t-butyl H), 7.70–7.71 (2 H, m, C(4Љ) H), 7.76 (2 H, d,
J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ) H), 7.77 (2 H, d,
J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ) H), 7.81 (1 H, dd,
J2Љ,4Љ = J6Љ,4Љ = 2.0 Hz, C(4Љ) H), 7.83 (1 H, dd, J2Љ,4Љ = J6Љ,4Љ = 2.0
Hz, C(4Љ) H), 7.83 (2 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and
C(6Љ) H), 7.85 (2 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ)
H), 7.86 (1 H, dd, J2Љ,4Љ = J6Љ,4Љ = 2.0 Hz, C(4Љ) H), 7.95 (1 H, dd,
J2Љ,4Љ = J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 8.01 and 8.22 (4 H, AAЈBBЈ,
C(2Ј) H, C(3Ј) H, C(5Ј) H, and C(6Ј) H), 8.07 (2 H, d,
J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ) H and C(6Љ) H), 8.08 (2 H,
d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ) H), 8.09 (2 H, d,
J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ) H), 8.27 (1 H, dd,
J2Љ,4Љ = J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 8.55 (1 H, s, bridge H), 8.65 (1 H,
s, bridge H), 8.63 and 8.64 (2 H, ABq, JAB = 5.0 Hz, β-pyrrolic
H), 8.68 and 8.71 (2 H, ABq, JAB = 5.0 Hz, β-pyrrolic H), 8.74
and 8.88 (2 H, ABq, JAB = 5.0 Hz, β-pyrrolic H), 8.76 (3 H, br s
24
2
Ϫ1
C, 82.11; H, 7.62; N, 7.61%; M, 4417.5]; νmax(CHCl )/cm 3351
3
(N-H); λmax(CH Cl )/nm (log ε) 429 (5.79), 454 (5.71), 507
2
2
(5.25), 614sh (4.62), 643 (4.71), and 686sh (4.41); δ (500 MHz;
H
CDCl ) Ϫ2.30 (4 H, s, NH), 1.48–1.60 (252 H, t-butyl H),
3
7.71 (4 H, dd, J2Љ,4Љ = J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 7.78 (8 H, d,
J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ) H and C(6Љ) H), 7.85 (8 H, d,
J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ) H and C(6Љ) H), 7.86 (2 H, dd,
J2Љ,4Љ = J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 7.88 (4 H, m, C(4Љ) H), 7.98 (2 H,
dd, J2Љ,4Љ = J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 8.00 (2 H, dd, J2Љ,4Љ
=
J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 8.10 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz,
C(2Љ) H and C(6Љ) H), 8.12–8.14 (12 H, m, C(2Љ)H, C(6Љ)H, and
phenylacetylene H), 8.36 (4 H, ¹AAЈBBЈ, phenylacetylene H),
and br ¹ABq, β-pyrrolic H), 8.93 (1 H, br ¹ABq, J = 5 Hz,
AB
¯
²
¯
²
¯
²
β-pyrrolic H), and 8.96 and 8.97 (2 H, br m, β-pyrrolic H).
cis/trans,endo-Bis(4Ј-iodophenyl)octakis(3Љ,5Љ-di-tert-butyl-
phenyl)bis-porphyrin nickel() 10 was isolated as a brown solid
8.59 (4 H, s, bridge H), 8.63 (4 H, s, β-pyrrolic H), 8.69 and 8.72
(4 H, ABq, JAB = 5.0 Hz, β-pyrrolic H), 8.70–8.72 (4 H, ABq,
JAB = 5.0 Hz, β-pyrrolic H), 8.82 and 8.83 (4 H, ABq, JAB = 4.5
Hz, β-pyrrolic H), 8.92 and 9.01 (4 H, br ABq, JAB = 5.0 Hz,
β-pyrrolic H), and 8.95 and 9.01 (4 H, br ABq, JAB = 5.0 Hz,
β-pyrrolic H).
(
21 mg, 41%), mp >300 ЊC [Found: C, 74.62; H, 6.71; N, 7.19;
m/z (FAB) 2279.7 (100%). C142H152N I requires C, 74.78; H,
12
2
6
4
.72; N, 7.37%; M, 2280.7]; λmax(CH Cl )/nm (log ε) 426 (5.45),
2 2
57 (5.39), 495sh (4.88), 608sh (4.24), 629 (4.26), and 677 (3.85);
δ (500 MHz; CDCl ) Ϫ2.34 to Ϫ2.29 (NH), 1.55–1.68 (t-butyl
H), 7.82–7.84 (m, C(4Љ) H), 8.00 (dd, J2Љ,4Љ = J6Љ,4Љ = 2.0 Hz, C(4Љ)
4,4Ј-Bis[endo-heptakis(3Љ,5Љ-di-tert-butylphenyl)bis-porphyrin-
nickel(II)]diphenylacetylene 11
H
3
H), 8.02–8.05 (m, C(2Љ) H, C(6Љ) H, and iodophenyl H), 8.10–
A solution of 9 (47 mg, 0.020 mmol), triphenylphosphine (2.4
mg, 0.009 mmol), palladium acetate (0.5 mg, 0.002 mmol), and
bis(tri-n-butylstannyl)acetylene (5.9 mg, 0.010 mmol) in tri-
8
.11 (m, C(2Љ) H and C(6Љ) H), 8.27 (¹ × AAЈBBЈ, iodophenyl
¯
²
H), 8.34 (¹ × AAЈBBЈ, iodophenyl H), 8.47 (dd, J = J6Љ,4Љ
=
2
Љ,4Љ
¯
²
2
(
9
.0 Hz, C(4Љ) H), 8.58 (s, bridge H), 8.68 (s, bridge H), 8.75–8.80
m, bridge H and β-pyrrolic H), 8.95–9.01 (m, β-pyrrolic H),
.03 (br ¹ABq, J = 5.0 Hz, β-pyrrolic H), and 9.22 (br ¹ABq,
3
ethylamine (4.5 cm ), was deoxygenated with argon for 10 min
and then heated at reflux for 5.5 h. The solvent was removed
and the residue was purified by column chromatography over
silica using a dichloromethane–light petroleum mixture (1:4) as
eluent and two bands were collected and the solvent completely
AB
¯
²
¯
²
JAB = 5.0 Hz, β-pyrrolic H). Dione 3 was isolated as a green
solid (43 mg, 48%) which co-chromatographed with and had an
1
identical H NMR spectrum to an authentic sample.
removed. Bis-porphyrin 9 was recovered as a brown solid (5 mg,
1
1
1%), which co-chromatographed with and had an identical H
Porphyrin dimer 13
NMR spectrum to an authentic sample. Diphenylacetylene 11
A solution of (4Ј-iodophenyl)tetrakis(3Љ,5Љ-di-tert-butylphenyl)-
porphyrin 12 (50 mg, 0.047 mmol), triphenylphosphine (5.0 mg,
was isolated as a brown solid (4 mg, 10%); λmax(CH Cl )/nm
2
2
(log ε) 430 (5.75), 450sh (5.60), 510 (5.09), 608sh (4.45), 641
(4.54), and 688sh (4.30); δ (500 MHz; CDCl ) Ϫ2.28 (2 H, s,
0
.019 mmol), palladium acetate (1.2 mg, 0.005 mmol), and
H
3
bis(tri-n-butylstannyl)acetylene (13.0 mg, 0.022 mmol) in tri-
ethylamine (5.0 cm ) was deoxygenated with argon for 13 min
and then heated at reflux for 3 h. The solvent was removed and
the residue was purified by column chromatography over silica
using a dichloromethane–light petroleum mixture (1:4 to
NH), Ϫ2.25 (2 H, s, NH), 1.50–1.59 and 1.80 (252 H, t-butyl
H), 7.73 (2 H, dd, J2Љ,4Љ = J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 7.76 (4 H, m,
C(4Љ) H), 7.82 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ)
H), 7.83 (2 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ) H and C(6Љ) H),
7.85 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ) H and C(6Љ) H), 7.86
(4 H, d, J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ) H and C(6Љ) H), 7.90 (6 H,
3
1
.5:3.5) as eluent and the main band was collected and the
solvent completely removed. Porphyrin dimer 13 was isolated
as a red solid (35 mg, 84%). A sample for analysis, recrystallised
from a dichloromethane–methanol mixture, had mp >300 ЊC
m, C(2Љ) H, C(4Љ) H, and C(6Љ) H), 7.98 (2 H, dd, J2Љ,4Љ =
J6Љ,4Љ = 1.5 Hz, C(4Љ) H), 8.11 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ)
H and C(6Љ) H), 8.12 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ) H and
C(6Љ) H), 8.13 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 1.5 Hz, C(2Љ) H and C(6Љ)
H), 8.44 and 8.50 (8 H, AAЈBBЈ, phenylacetylene H), 8.52 (2 H,
br dd, C(4Љ) H), 8.61 (2 H, s, bridge H), 8.67 and 8.69 (4 H,
ABq, JAB = 5.0 Hz, β-pyrrolic H), 8.74 and 8.75 (4 H, ABq,
JAB = 5.0 Hz, β-pyrrolic H), 8.78–8.80 (8 H, m, bridge H and
[Found: C, 85.92; H, 8.14; N, 5.75; m/z (FAB) 1924.8 (100%).
C138H154N requires C, 86.11; H, 8.06; N, 5.82%; M, 1924.8];
8
Ϫ1
νmax(KBr disc)/cm 3316 (N-H); λmax(CH Cl )/nm (log ε) 425
2
2
(
(
6.00), 490 (3.98), 518 (4.65), 555 (4.46), 593 (4.11), and 649
4.16); δ (500 MHz; CDCl ) Ϫ2.65 (4 H, s, NH), 1.55 (108 H, s,
H
3
t-butyl H), 7.81 (2 H, dd, J2Љ,4Љ = J6Љ,4Љ = 2.0 Hz, C(4Љ) H), 7.83
β-pyrrolic H), 8.91 (2 H, br ¹ABq, J = 5.0 Hz, β-pyrrolic H),
AB
¯
²
(
4 H, dd, J2Љ,4Љ = J6Љ,4Љ = 2.0 Hz, C(4Љ) H), 8.10 and 8.34 (8 H,
8.97–9.02 (6 H, br m, β-pyrrolic H), and 9.14 (2 H, ¹ABq,
¯
²
AAЈBBЈ, phenylacetylene H), 8.11 (4 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz,
C(2Љ) H and C(6Љ) H), 8.13 (8 H, d, J4Љ,2Љ = J4Љ,6Љ = 2.0 Hz, C(2Љ)
H and C(6Љ) H), 8.94–8.97 (16 H, m, β-pyrrolic H).
JAB = 5.0 Hz, β-pyrrolic H) [Found: m/z (MALDI) 4418.6
(100%). C302H334N Ni requires M, 4417.5].
24
2
[
5(4Ј-Iodophenyl)-10,15,20-tris(3Љ,5Љ-di-tert-butylphenyl)-
4
,4Ј-Bis[exo-heptakis(3Љ,5Љ-di-tert-butylphenyl)bis-porphyrin-
porphinato]nickel(II) 16
nickel(II)]diphenylacetylene 7
A solution of (4Ј-iodophenyl)tetrakis(3Љ,5Љ-di-tert-butylphenyl)-
porphyrin 12 (100 mg, 0.093 mmol) and nickel() acetate tetra-
hydrate (83 mg, 0.33 mmol) in dimethylformamide (50 cm ) was
A solution of 5 (53 mg, 0.023 mmol), triphenylphosphine (5.0
mg, 0.019 mmol), palladium acetate (0.7 mg, 0.003 mmol), and
3
J. Chem. Soc., Perkin Trans. 1, 2000, 1231–1240
1239

View Article Online
Y. Nishimura, Angew. Chem., Int. Ed., 1998, 37, 3023; (g) H. A.
heated at reflux for 40 min and then allowed to cool. Ether (100
3
Biemans, A. E. Rowan, A. Verhoeven, P. Vanoppen, L. Latterini,
J. Foekema, A. P. H. J. Schenning, E. W. Meijer, F. C. de Schryver
and R. J. M. Nolte, J. Am. Chem. Soc., 1998, 120, 11054; (h) P. N.
Taylor, A. P. Wylie, J. Huuskonen and H. L. Anderson, Angew.
Chem., Int. Ed., 1998, 37, 986; (i) M. J. Crossley and P. L. Burn,
J. Chem. Soc., Chem. Commun., 1991, 1569; (j) E. J. Atkinson,
A. M. Oliver and M. N. Paddon-Row, Tetrahedron, 1993, 34, 6147.
(a) C. C. Mak, N. Bampos and J. K. M. Sanders, Chem. Commun.,
cm ) was added and the solution washed with water (5 × 50
3
cm ), dried over anhydrous sodium sulfate, filtered, and the
solvent completely removed. The residue was passed through a
plug of silica using a dichloromethane–light petroleum mixture
(
1:4) as eluent and the main band was collected and the solvent
was completely removed to give 16 as a red solid (105 mg, 100%).
A sample for analysis was recrystallised from a dichloro-
methane–methanol mixture, mp >300 ЊC [Found: C, 71.80; H,
2
1
1
999, 1085; (b) G. S. Wilson and H. L. Anderson, Chem. Commun.,
999, 1539; (c) J. Fan, J. A. Whiteford, B. Olenyuk, M. D. Levin,
6
.68; N, 4.81; m/z (FAB) 1133.3 (100%). C H N INi requires
68 75 4
P. J. Stang and E. B. Fleischer, J. Am. Chem. Soc., 1999, 121, 2741;
(d) M. Gardner, A. J. Guerin, C. A. Hunter, U. Michelsen and
C. Rotger, New J. Chem., 1999, 23, 309.
C, 72.03; H, 6.67; N, 4.94%; M, 1134.0]; λmax(CH Cl )/nm (log
2
2
ε) 418 (5.40), and 529 (4.24); δ (500 MHz; CDCl ) 1.47 (18 H, s,
H
3
t-butyl H), 1.48 (54 H, t-butyl H), 7.71–7.73 (3 H, m, C(4Љ) H),
.77 and 8.02 (4 H, AAЈBBЈ, C(3Ј) H, C(4Ј) H, C(5Ј) H, and
C(6Ј) H), 7.87 (6 H, m, C(2Љ) H and C(6Љ) H), 8.72 and 8.79
4 H, ABq, JAB = 5.0 Hz, β-pyrrolic H), and 8.82 (4 H, s, β-
3 R. W. Wagner, T. E. Johnson and J. S. Lindsey, J. Am. Chem. Soc.,
996, 118, 11166.
R. Beavington and P. L. Burn, J. Chem. Soc., Perkin Trans. 1, 2000,
05.
R. Beavington and P. L. Burn, J. Chem. Soc., Perkin Trans. 1, 1999,
83.
R. Beavington, P. A. Rees and P. L. Burn, J. Chem. Soc., Perkin
Trans. 1, 1998, 2847.
P. L. Burn, PhD Thesis, Sydney University, Australia, 1989.
1
7
4
5
6
7
6
(
pyrrolic H).
5
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