Phthalocyaninodehydroannulenes

Article abstract of DOI:10.1002/1521-3765(20001103)6:21<3958::AID-CHEM3958>3.0.CO;2-Y

4-Bromo- and 4,5-dibromo-3,6-dibutoxyphthalonitrile have been prepared and treated with 3,6-didecylphthalonitrile in cross tetramerisation reactions in the presence of nickel acetate to afford monobromo- and dibromo-dibutoxyhexadecylphthalocyaninato nicke

Full text of DOI:10.1002/1521-3765(20001103)6:21<3958::AID-CHEM3958>3.0.CO;2-Y

FULL PAPER
Phthalocyaninodehydroannulenes
Michael J. Cook* and Martin J. Heeney[a]
Abstract: 4-Bromo- and 4,5-dibromo-
3,6-dibutoxyphthalonitrile have been
prepared and treated with 3,6-didec-
ylphthalonitrile in cross tetramerisa-
tion reactions in the presence of nickel
acetate to afford monobromo- and di-
bromo-dibutoxyhexadecylphthalocyani-
nato nickel(ii) complexes.Sonogashira
and Stille coupling reactions on these
compounds displaced the bromine sub-
stituents by ethynyl groups.Oxidative
coupling of the monoethynyl derivatised
nickel phthalocyanine afforded a buta-
diynyl-linked dinuclear phthalocyanine.
The corresponding coupling reaction of
triphthalocyaninodehydro[18]annulene,
has been identified as a minor product.
Both compounds show a large splitting
of the Q-band absorption in the visible
region spectrum.Most of the mononu-
clear phthalocyanine precursors exhibit
discotic liquid crystal behaviour.The
diphthalocyaninodehydro[12]annulene
also enters a mobile phase on heating,
but undergoes an irreversible change at
2208C.MALDI-TOF mass spectrome-
try of the product reveals that the
compound undergoes oligomerisation
at this temperature.
the diethynylated phthalocyanine gave a
mixture of phthalocyaninodehydroan-
nulenes.Separation of the mixture yield-
ed the diphthalocyaninodehydro[12]an-
nulene as the major product.Electro-
spray mass spectrometry provides
evidence for its aggregation in solution.
The corresponding cyclic trimer, the
Keywords: annulenes ´ liquid crys-
tals ´ phthalocyanines ´ phthalocya-
ninoannulenes
years has also seen the successful application of palladium-
catalysed coupling reactions in phthalocyanine synthesis, and
this has provided access to alkynyl Pcs[10±13] of which some
monoalkynyl derivatives[13] have been oxidatively coupled to
give ªdinuclearº Pcs linked through an ethynyl or butadiynyl
moiety.Examples of some of these compounds and related
structures have interesting NLO effects.[14]
The research described herein exploits similar coupling
chemistry to synthesise yet more complex structures in which
Pc moieties are conjugated through fusion to a dehydroannu-
lene, a ring system which is currently attracting a resurgence
of interest in its own right.[15, 16] The oxidative coupling step
(Scheme 1) provides a diphthalocyaninodehydro[12]annulene
Introduction
Phthalocyanines (Pcs) are macrocyclic compounds whose 18p
electron system provides the basis for their remarkable
photophysical, optoelectronic and conductiometric proper-
ties.[1] The compounds have a characteristic bright blue-green
colour arising from an intense p ± p* transition in the visible
region, the Q-band, a property widely exploited for well over
60 years in the dye and pigment industry.[2] More recently,
phthalocyanines have made an impact in ªhigh techº areas, as
exemplified by their use as the charge carriers in electro-
photography[3] and as the dye component in optical data
storage systems.[4] Furthermore, their properties have been
identified as having potential for exploitation in a number of
other fields including gas sensing,[5] photovoltaic cells,[6]
optical limiting[7] and the photodynamic therapy of cancer.[8]
The versatility of these macrocycles has led to the develop-
ment of more elaborate derivatives.In particular, attention
has been given to devising means whereby the p system is
extended or distorted.Compounds containing two Pc cores
that share a common benzene ring have been synthesised and
provide interesting, elongated planar structures.[9] The last few
Pc
Pc
Pc
n
Scheme 1.A schematic representation of the oxidative coupling of a
diethynylphthalocyanine into a dehydroannulene; n is an integer.
(n ˆ 1 in Scheme 1) as the major product.A minor product
has been identified as the corresponding triphthalocyanino-
dehydro[18]annulene (n ˆ 2).Both compounds have been
shown to undergo oligomerisation, apparently by reaction at
the dialkynyl moiety.
[a] Prof.M.J.Cook, Dr.M.J.Heeney
School of Chemical Sciences, University of East Anglia
Norwich, NR4 7TJ (UK)
Fax : (‡44)1603-592015
E-mail: m.cook@uea.ac.uk
3958
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3958 $ 17.50+.50/0
Chem. Eur. J. 2000, 6, No. 21

3958±3967
for the subsequent oxidative coupling reaction, we also
required the corresponding monoalkynyl phthalocyanines
2a and 2b.Access to 1 and 2 was sought from the
corresponding di- and mono-bromo analogues 3 and 4,
respectively (Scheme 2).Therefore, compounds 3 and 4
provided the first synthetic targets.
Results and Discussion
Synthesis
General considerations: The chemistry represented in
Scheme 1 requires a phthalocyanine that carries two adjacent
ethynyl groups on one of the four benzenoid rings.Hitherto,
Leznoff and co-workers[12] have reported the synthesis of an
octaalkynylphthalocyanine (with two alkynyl groups on all
four benzenoid rings) from dialkynylphthalonitrile, the latter
synthesised from the corresponding diiodophthalonitrile.
These authors commented upon the phthalocyanineꢁs pro-
Synthesis of brominated Pcs 3 and 4: Compounds 3 and 4 are
examples of so-called 3:1 phthalocyanines, that is, derivatives
in which three of the benzenoid rings have common sub-
stituents and the fourth bears different substituents.Such
compounds can, in principle, be prepared by several meth-
ods;[14, 18] here we have utilised the cross-cyclotetramerisation
approach, the reaction together of two appropriately sub-
stituted phthalonitriles.The precursors used for the synthesis
of 3 and 4 are outlined in Scheme 2.The synthetic pathway
commences with the bromination of 2,3-dicyanohydroqui-
none 5 to afford the dibrominated product 6. In our hands the
use of Guentherꢁs method,[19] bromine in acetic acid, provided
a product which gave a low analysis for bromine.However,
bromination of 5 by using N-bromosuccinamide (NBS),[20]
followed by sodium metabisulfite reduction of the 2,3-
pensity to self aggregate.In the present work, structure
1
(TMS-protected (1a, TMS ˆ trimethylsilyl) or unprotected
(1b), Scheme 2) was designed as a key synthetic intermediate.
It has a number of substituent chains in the nonperipheral (1,
4, 8, 11, 15, 18, 22, 25) sites designed both to limit aggregation
and to promote solubility in organic solvents.[17] As a model
OH
OH
Br
Br
CN
CN
CN
CN
i)
OH
OH
dibromo-4,5-dicyanobenzoquinone so-formed, gave
6 in
iii)
5
ii)
6
66% yield.Alkylation of compound 6, unexpectedly and
fortuitously, provided access to both 7 and 8.Hence iodobu-
tane in the presence of potassium carbonate in methyl ethyl
ketone (MEK) gave a mixture of 7 (6%) and 8 (39%).The
latter was formed exclusively (42%) by delaying addition of
iodobutane to the basic solution.This implies that the role of
the base is to eliminate HBr from 6, presumably via its
tautomer.The resulting monobromobenzoquinone may then
be reduced back to the monobromohydroquinone, which then
undergoes conventional Williamsonꢁs ether synthesis.Con-
ditions could not be found which favoured the formation of 7
over 8 in this type of alkylation reaction.Instead, compound 7
was obtained conveniently and in satisfactory yield (84%)
from 6 by using Mitsunobu conditions.
OBu
OBu
R
OBu
OBu
Br
Br
CN
CN
CN
CN
CN
Br
CN
R
9
7
8
iv)
iv)
R = C10H21
R
R
R
R
R
OBu
OBu
R
R
OBu
N
N
N
N
N
N
N
N
N
N
Ni
N
X
Ni
N
N
N
N
Mixed cyclotetramerisation of 7 and 9 (R ˆ C10H21),[21] ratio
1:9, was undertaken by using lithium butoxide in butanol in
the presence of nickel acetate.Chromatographic separation
readily removed the self condensation product of 9, namely
1,4,8,11,15,18,22,25-octadecylphthalocyaninato nickel(ii), as
the first fraction.The second fraction contained two compo-
nents which were separated on a second column.One proved
to be the required compound 3, identified by a cluster at
1714 D in the low-resolution FAB-mass spectrum, elemental
Br
Br
N
R
OBu
R
R
R
R
3
X = Br
10 X = OBu
4
v) or vi)
v) or vi)
11 X = CCSiMe3
R
R
R
R
R'
R'
R
R
OBu
OBu
R
R
OBu
OBu
N
N
N
N
N
N
N
N
N
Ni
N
N
Ni
N
1
analysis and an H NMR spectrum, which were consistent
N
N
N
N
with the expected structure.The second was identified as
compound 10 on the basis of elemental analysis and the
MALDI-TOF mass spectrum.The latter gave a signal for the
molecular ion at 1707 D; FAB-MS showed a cluster corre-
R'
R
R
R
R
‡
sponding to [M À C4H9O] . 13C NMR confirmed the presence
2 a R' = SiMe3
b R' = H
of three different butoxy groups in the molecule.
1 a R' = SiMe3
b R' = H
The formation of 10 was unexpected; phthalocyanines
formed from 3,6-dialkoxy-4,5-dichlorophthlonitrile show evi-
dence of ipso displacement of the alkoxy group by alkoxide
derived from the solvent, but not displacement of the
halogen.[22] Attempts to convert 3 into 10 under the conditions
of the cyclotetramerisation reaction failed; this suggests that
Scheme 2.Synthetic pathway to the required diethynylated phthalocya-
nine intermediates 1a and 1b and the monoethynylated phthalocyanine
analogues 2a and 2b. R ˆ decyl throughout.i) NBS, Na 2S2O5.ii) DIAD,
Ph3P, BuOH.iii) K 2CO3, BuI.iv) LiOBu/BuOH, (AcO) 2Ni.4H2O.v) For
3 ! 1a (and 11) and 4 ! 2a: HCC-SiMe3, [Pd(PPh3)2Cl2], Ph3P, CuI.
vi) For 3 ! 1b and 4 ! 2b: HCC-SnBu3, [Pd(PPh3)4].
Chem. Eur. J. 2000, 6, No. 21
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3959 $ 17.50+.50/0
3959

M.J.Cook, M.J.Heeney
FULL PAPER
the butoxy group displaced the bromine atom on the
phthalonitrile 7 prior to cyclisation.Subsequent preparations
of 3 were performed by using either 0.5 equivalents of lithium
butoxide in butanol, or NH3 in DMAE to suppress formation
of undesired 10.No evidence of bromide displacement was
found during the corresponding cross cyclotetramerisation of
8 and 9 to give 4 although not all components of the product
mixture were identified systematically.
Oxidative coupling of 2a and 1b : Deprotection of 2a to give
2b and the subsequent copper-mediated coupling of 2b into
the butadiynyl-linked dinuclear phthalocyanine 12 (Scheme 3),
Synthesis of ethynylated Pcs 1a, 1b, 2a and 2b: The
conversions of 3 and 4 into the ethynylated compounds were
investigated by using both the Sonogashira coupling meth-
od,[23] which led to the TMS-protected derivatives 1a and 2a
(TMS ˆ trimethylsilyl), and the Stille procedure,[24] which led
directly to the unprotected compounds 1b and 2b.
Sonogashira coupling was first applied to 4 with Et3N as
solvent.The compound was treated with trimethylsilylethyne
(6 equivalents) at 808C for 36 hours in the presence of
[Pd(PPh3)2Cl2] (20 mol%) and CuI (30 mol%) with addi-
tional catalyst added after 24 h.No cross coupling occurred.
However, change of solvent to THF/Et3N (5:1), an increase in
the amount of CuI (39 mol%) and addition of PPh3 satisfac-
torily converted 4 into the TMS-protected ethynyl Pc 2a.This
was obtained in 62% yield after chromatographic purifica-
tion.The product gave a cluster corresponding to the
molecular ion at 1653 D in the FAB mass spectrum and a
1H NMR signal at d ˆ 0.49 for the nine trimethylsilyl protons.
Stille coupling of 4 with tributyl(ethynyl)tin and [(Ph3P)4Pd]
as catalyst, stabilised by added Ph3P and lithium chloride, was
less satisfactory, affording 2b in 48% yield.The compound
1
was characterised by elemental analysis and H NMR spec-
troscopy.
The Sonogashira conditions used above were applied to the
conversion of 3 into 1a, but with only limited success.Despite
varying conditions, the required product 1a was never
obtained in a yield greater than 35% and was always
accompanied by the incompletely reacted compound 11.
Compound 1a was identified by a cluster at 1747 D in the
MALDI-TOF mass spectrum and a characteristic 18 proton
singlet in the 1H NMR spectrum for the trimethylsilyl protons.
13C NMR spectroscopy provided further confirmation of the
structure.All 16 of the expected aromatic 13C signals were
well resolved and the two ethynyl carbons gave signals at d ˆ
104.74 and 100.97. Deprotection of 1a by using aqueous KOH
in THF/methanol medium afforded 1b in 79% yield.This was
characterised by a cluster at 1606 D in the FAB mass
Scheme 3.Structures of compounds; R ˆ decyl throughout.Compound 12
is obtained from 2a via 2b.Compounds 14 and 15 are recovered from the
oxidative coupling of 1b.Compound 13 is an intermediate in the
conversion of 1b into 14 and 15.
was undertaken in one pot.The preferred conditions utilised
potassium carbonate and copper(ii) acetate in dry THF/
pyridine/methanol (3:1:1).Compound 12, obtained in 61%
yield, gave a MALDI-TOF mass spectrum showing a cluster
at 3161 D and a satisfactory elemental analysis.The 1H NMR
spectrum ([D6]benzene) was broadened at room temperature,
but aggregation was sufficiently disrupted at 508C for the
spectrum at this temperature to show signals consistent with
the structure given.In particular the two types of butoxy
1
spectrum, elemental analysis and H and 13C NMR spectra,
which showed signals fully consistent with the structure given.
The Stille coupling procedure, used above, satisfactorily
converted 3 directly into 1b in 60% yield.Hence, in this case
Stille coupling offered a significant improvement over the
Sonogashira method in terms of overall yield.Furthermore,
there was less difficulty in separating the fully and partially
coupled product, which required careful chromatography in
the case of the Sonogashira procedure.
À
groups were apparent from the two triplets for the CH2O
protons at d ˆ 5.03 and 4.46.
In summary, the coupling methods described above pro-
vided satisfactory stocks of 2a and 1b for oxidative coupling
experiments.
Though the synthesis of 12 was undertaken as a model study
for the main theme of the work, its isolation provided a novel
example for the limited number of butadiynyl-linked dinu-
3960
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3960 $ 17.50+.50/0
Chem. Eur. J. 2000, 6, No. 21

Phthalocyaninoannulenes
3958±3967
clear phthalocyanines currently known.[13] It is distinguished
from those reported previously during the development of
this class of compound by Torresꢁ group in so far as the
substitution pattern here ensures that the product is obtained
as a single isomer.The product also bears alkoxy groups,
substituents known to cause a bathochromic shift of the
Q-band.The Q-band is split: lmax ˆ 702 and 752 nm.Split
Q-bands are expected for metallated macrocycles of lower
[25]
symmetry than D4h and are indeed observed for all of the
mononuclear precursor phthalocyanines prepared in this
study, see Table 1.However, for 12 the splitting is much
greater, compare with the precursor 2, lmax ˆ 700 and 722 nm,
Table 1.UV/Vis spectroscopic data of solutions (in toluene).
2- and 3-substituents
lmax [nm] (loge)
1a
1b
2a
2b
3
4
10
12
14
15
CCSiMe3, CCSiMe3
CCH, CCH
CCSiMe3, H
CCH, H
Br, Br
Br, H
Br, OBu
butadiynyl (dinuclear Pc)
dehydro[12]annulene
dehydro[18]annulene
732 (4.99), 702 (4.95)
729(4.99), 698 (4.88)
722 (5.09), 700 (5.02)
721 (5.07), 701 (5.01)
716 (5.10), 698 (5.03)
714 (5.10), 700 sh.
714 (5.21), 698 sh.
752 (5.43), 702 (5.27)
823 (5.32), 691 (4.93)
780, 698[a]
[a] Insufficient material available for a quantitative evaluation of e.
Table 1.Large splittings have been reported for other
butadiynyl-linked dinuclear phthalocyanines with the notable
exception of a nickel-containing derivative.[13]
Oxidative coupling of 1b mediated by copper(ii) acetate in
THF/pyridine/methanol (4:4:1) was investigated over a vari-
ety of conditions and was monitored by visible-region
spectroscopy.Compound 1b exhibits a split Q-band absorp-
tion, lmax ˆ 698 and 729 nm (Figure 1, top, line i).The
spectrum of the reaction mixture taken after 20 minutes at
Figure 1.UV-visible spectra (toluene) measured in 1 mm pathlength cells.
Top: Line i): compound 1b; line ii): spectrum of the oxidative cross
coupling product from 1b after 48 h at 508C.Middle: Spectrum of 14.
Bottom: Spectrum of 15.
The first fraction, lmax ˆ 691 and 822 nm (Figure 1, middle),
gave a MALDI-TOF mass spectrum showing an isotopic
cluster at 3206 D which corresponds to a singly charged
molecular ion of the diphthalocyaninodehydro[12]annulene
(14, Scheme 3).Scanning to 6500 D gave no indication of
508C is broadened and there are prominent peaks at lmax
ˆ
701 and 756 nm.These maxima are closely similar to the
Q-band absorptions of compound 12, see above, and are
consistent with the presence of the partially coupled inter-
mediate 13 (Scheme 3).Continuation of the reaction trans-
formed the spectrum and led to a new absorption at 822 nm.
The intensity of this band did not increase further after
48 hours (Figure 1, top, line ii).The same spectrum was also
obtained from the product mixture of a separate coupling
reaction of 1b (39 mg) after eight hours at 808C.The crude
reaction products were filtered through silica (eluent: petrol/
THF 9:1) to remove copper salts and polymeric material.The
MALDI-TOF mass spectrum showed clusters centred at
3206 D (100%), and lower intensity clusters at 4809 and
6412 D.These correspond to a cyclic dimer, trimer and
tetramer, that is, n ˆ 1, 2 and 3 in Scheme 1.Preparative size-
exclusion chromatography with SephadexTM LH-20 did not
effect a satisfactory separation.However, a partial separation
over silica (petrol/THF 19:1) afforded a larger fraction
(9.5 mg) and a smaller fraction (3.2 mg). A much smaller
third fraction was discarded.
higher molecular weight species.The second fraction, lmax
ˆ
698, 783, shoulder at 822 nm, gave two clusters in the
MALDI-TOF spectrum.The smaller one, about 15% of the
base peak, corresponds to 14 (accounting for the shoulder at
822 nm in the absorption spectrum).The base peak at 4809 D
corresponds to the cyclic trimerisation product 15.The
preferential formation of the dehydro[12]annulene derivative
14 over the trimerisation product 15 (Scheme 3) and other
higher molecular weight cyclisation products is in accord with
the results of oxidative couplings of other dialkyne sys-
tems.[15, 16]
A sample of 14 and the fraction that contained 15
contaminated with 14 were further examined by gel-perme-
ation chromatography (GPC).Compound 14 exhibited a
single peak, retention time 93.3 min, with Mw ˆ 3430 and
Mn ˆ 3373 (polystyrene equivalent molecular mass) to give a
polydispersity (Mw/Mn) of 1.02, which corresponds to a single
component.The mass data are in satisfactory agreement with
the expected molecular mass.The second fraction exhibited
Chem. Eur. J. 2000, 6, No. 21
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3961 $ 17.50+.50/0
3961

M.J.Cook, M.J.Heeney
FULL PAPER
two peaks, retention times 90.3 min and 93.3 min, in an
approximate 8:1 ratio.The first peak corresponded to the
trimerisation product 15, with Mw ˆ 4909 and Mn ˆ 4867 (Mw/
Mn ˆ 1.01), and was collected. The second peak corresponded
to the small amounts of 14 which had not been completely
separated from 15 by the earlier column chromatographic
purification.
signal corresponds to the doubly charged [M]2‡ ion at
1601.1211 (requires 1601.1235). The isotopic distribution,
Figure 2 (middle), shows a 0.5 D mass difference between
‡
each peak.Signals for the single and triple charged ions, [ M]
and [M]3‡, are also present, at about 3206 D (poorly resolved)
and at 1067.4227 ([M]3‡ requires 1067.4157), respectively.
Further signals are also present which indicate the presence of
aggregated structures.The peak cluster at 2135 D and its mass
spacings (Figure 2, bottom) correspond to a triply charged,
two-molecule aggregate.The very low intensity peak at
approximately 2400 corresponds to a quadruply charged,
three-molecule aggregate.
Characterisation of the phthalocyaninoannulenes 14 and 15:
The high-resolution FT-ICR electrospray ionisation mass
spectrum of 14 in THF is shown in Figure 2 (top).The base
The molecular weight of 15 is beyond the range of the FT-
ICR electrospray equipment used to characterise 14 and its
structure was confirmed by MALDI-TOF MS.The isotopic
cluster for 15 is shown in Figure 3 and is superimposable on
‡
the calculated distribution for [M‡H] .This correspondence
precludes the presence of an incompletely coupled, open
chain, trinuclear phthalocyanine.
1
The H NMR spectrum of 14 (4.5 mg per 0.5 mL [D6]ben-
zene) shows broadening of the signals for the aromatic, OCH2
and benzylic protons.Introduction of [D ]pyridine failed to
5
inhibit aggregation at this concentration.At higher dilution
(ca. 0.9 mg per 0.5 mL [D6]benzene) and at 408C the 1H NMR
spectrum is well resolved.Apart from the expected mutiplets
for the aliphatic protons, the spectrum shows overlapping
signals for the aromatic protons, an eight-proton triplet at d ˆ
4.91 for the OCH2 protons, a triplet for eight benzylic protons
at d ˆ 4.76 and a 16-proton multiplet for the remaining
1
benzylic protons centred at d ˆ 4.62. The H NMR spectral
data for 15 were collected under similar conditions from a
sample from column chromatography and prior to GPC
separation from small amounts of 14.The spectrum showed
signals consistent with the structure given and also revealed
that the ratio of 14:15 was about 1:8.Interestingly, this
spectrum showed clearly that the signals for the OCH2
protons of 15 (d ˆ 5.12) are downfield of those of 14, (d ˆ
1
4.91). Matzger and Vollhardt[26] recently appraised H NMR
spectral data for dibenzodehydro[12]annulene and tribenzo-
dehydro[18]annulene and ascribed the difference in chemical
shifts of the ortho aromatic protons of these planar molecules
to the fact that the former is paratropic (anti-aromatic),
whereas the latter is diatropic (aromatic).The difference
observed in the chemical shifts of the OCH2 protons in 14 and
15 can be attributed similarly.
The most striking feature of the Q-band absorptions for 14
and 15 is the splitting, which is much greater than for the
butadiynyl-linked dinuclear phthalocyanine 12.Of the two,
the splitting observed in the spectrum of 14 is the larger which
may reflect the greater strain in the system.
Mesophase behaviour: The phthalocyanine precursors to the
dinuclear and dehydroannuleno derivatives were investigated
for liquid crystallinity as a routine element of their character-
isation.Hitherto, we have described the columnar mesophase
properties of a large number of nonperipherally substituted
phthalocyanines both uniformly substituted, with either eight
alkyl[27] or eight alkyloxymethyl groups,[28] and 3:1 non-
uniformly substituted derivatives bearing at least six alkyl
Figure 2.Top: The high-resolution FT-ICR electrospray ionisation mass
spectrum of 14 in THF over the mass range 500 to 4000D.ªMonomerº
refers to unaggregated molecules, ªDimerº and ªTrimerº to two and three
molecule aggregates, respectively.( ‡1), (‡2) and (‡3) refer to the number
of charges per species deduced from the peak separations, not shown,
within the individual clusters (see text).Middle: The isotopic cluster at
1601 corresponding to the [M]2‡ species.Bottom: The isotopic cluster at
2135 corresponding to the triply charged dimeric aggregate.
3962
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3962 $ 17.50+.50/0
Chem. Eur. J. 2000, 6, No. 21

Phthalocyaninoannulenes
3958±3967
‡
Figure 3.Lower plot: The MALDI-TOF spectrum of the [ M ‡ H] species for compound 15. Upper plot: The calculated isotopic cluster for this species.
chains.[29] Non-peripherally substituted octaalkoxy derivatives
do not show mesophase behaviour.[22]
symmetry, whilst the remaining deca-substituted Pcs have C2v
symmetry.The Cs Pcs exhibit lower K ! Dhd transitions than
the analogous C2v Pcs.This can be attributed to the more
symmetrical Pcs forming better packed crystals.Secondly, the
Cs Pcs exhibit higher clearing points (K ! I or Dhd ! I) than
The liquid crystal behaviour of the present 3:1 Pcs was
examined by optical polarising microscopy, and the results are
summarised in Table 2; K refers to the crystal state, D to a
mesophase (discotic) and I is the isotropic liquid.All but 1a
exhibited mesophase behaviour; this indicates that inclusion
of two alkoxy groups in the nonperipheral positions does not
inhibit liquid crystallinity.Without exception, the first meso-
phase observed upon cooling gave rise to a ªfanlikeº
birefringence texture, which is characteristic of a discotic
hexagonal disordered phase (Dhd) in accordance with the
examples referred to above.[27±29] The monobromo derivative,
4, exhibited a second mesophase, but only during cooling.This
phase was mobile and distorted under external pressure.It
gave rise to an indistinct texture and has not been identified.
Here we denote it as Dx.
their C2v counterparts.The D mesophase of the Cs Pcs was
hd
much more mobile and less viscous than for the C2v Pcs.The Cs
Pcs also had a tendency towards supercooling, with crystal-
lisation occurring upon standing overnight at room temper-
ature.By contrast, the C2v Pcs crystallised directly upon
cooling.The transition to the crystal was characterised by a
colour change, not a change in texture, the ªfansº becoming a
lighter green.Replacement of the bromine atoms with
unprotected ethynyl groups increased clearing transitions.
The butadiynyl derivative 12 melted directly into the
isotropic liquid phase.On cooling, a texture was generated
similar to the fan texture referred to above.However, this is
assigned to a crystal phase because differential scanning
calorimetry showed single, broad endotherms for the K ! I
and I ! K transitions, rather than the sharp peaks associated
with mesophase transitions.
The symmetry of the molecule has a marked affect upon the
mesophase behaviour.Hence, the nona-substituted Pcs, 2a,
2b, and 4 and the deca-substituted compound 10 are of Cs
Table 2.Transition temperatures measured for ªmononuclear phthalocyaninesº.
Furthermore, crystallisation oc-
Compound[a]
Substituents
Transition temperatures [8C][b]
curred with some degree of
supercooling.In contrast,
K ! Dhd
Dhd ! I
K ! I
I ! K
I ! Dhd
Dhd ! Dx
Dx ! K
Dhd ! K
a
sample of the dehydro[12]an-
nulene derivative 14 entered a
mobile phase at about 1108C; a
phase which gave rise to a
birefringence pattern.Thus we
tentatively conclude that this
complex molecule also exhibits
mesophase behaviour.Howev-
er, further heating produced an
1a
1b
2a
2b
3
2 Â CCSiMe3
2 Â CCH
CCSiMe3
CCH
69
< RT
83
46
36
91
113
131
88
112
130
67.5
104
84
76
< RT
< RT
57
2 Â Br
72
4
10
Br
30
65
106
87
35
< RT
Br, OBu
< RT
[a] Central ion is nickel.[b] Transition temperatures measured by polarised light microscopy on the first heating
and cooling cycle.[c] The higher temperature mesophase is assigned as D hd.The lower temperature mesophase
Dx is unknown.
Chem. Eur. J. 2000, 6, No. 21
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3963 $ 17.50+.50/0
3963

M.J.Cook, M.J.Heeney
FULL PAPER
irreversible change, see below, which hindered mesophase
characterisation.
Q-band, and the chemical shifts of protons in proximity to the
annulene ring are deshielded.The compound also undergoes
oligomerisation, but less readily than the diphthalocyanino-
dehydro[12]annulene.
Thermal polymerisation experiments: Acyclic dialkynes are
well known to polymerise[30] under thermal and photochem-
ical conditions, but much less is known about cyclic di-
alkynes.[16] A sample of the butadiynyl derivative 12 was
maintained at 2208C for two hours.After cooling, the visible
region spectrum of the material in solution and the TLC
behaviour were identical to those of the starting material.
Compounds 14 and 15, the latter contaminated with 14, were
investigated similarly.After five minutes at 220 8C, 14 gave a
spectrum (toluene solution) that showed reduction in absorb-
ance of the two main components of the Q-band and growth
of a broad band between them.This change was irreversible.
Continued heating for 30 minutes gave a sample whose
spectrum showed the disappearance of the original bands
and their replacement by a featureless band envelope
extending over the region 680 ± 820 nm.The sample of 15
showed similar changes, but over a much longer timespan.The
heated sample of 14 gave a MALDI-TOF spectrum with a
series of broadened peaks for high molecular weight species,
the highest at approximately 19000 D.These were spaced at
multiples of the molecular weight of 14.A second series of
peaks appear at intervening molecular weights.Clearly the
material has undergone oligomerisation, but interpretation is
complex because of the possible presence of multiply charged
ions.The compoundꢁs facility for reaction contrasts with that
of 12 and 15, and this can be attributed to the strain associated
with the inevitable distortion of the dialkyne moiety in the
dehydro[12]annulene system.Further work is required to
characterise the high molecular mass structures in more
detail.
These compounds extend the range of highly elaborated
phthalocyanine derivatives available; they also add to the
type of annelated dehydroannulene compounds which are
known.In addition, the results indicate that the thermally
induced oligomerisation processes undergone by the annu-
lene moiety in this type of system provides an entry to novel
phthalocyanine-networked polymers, a topic we shall inves-
tigate in more detail in future work.
Experimental Section
IR spectra were recorded on a Perkin ± Elmer 297, 298 or a FTIR 1720
spectrophotometer as either neat liquids or as nujol mulls of solids.
1H NMR spectra were measured at 270 MHz with
a JEOL EX270
spectrometer and at 300 MHz with a Varian Gemini 2000, with TMS or
the residual solvent peak as the reference.Routine mass spectra were
recorded on a Kratos model MS25 magnetic sector mass spectrometer with
electron impact ionisation.FAB-MS (LSIMS) were obtained by using
nitrobenzyl alcohol as the matrix and were measured with the EPSRCꢁs
VG ZAB-E low-resolution equipment at Swansea University.MALDI-
TOF mass spectra were obtained on
a Kratos Kompact MALDI3
spectrometer with a dithranol matrix at the University of Manchester.
FT-ICR electrospray mass spectra were obtained of a solution of 14 in THF
with a Bruker 9.4-T FT-ICR at the University of Warwick. GPC analysis
was carried out at the University of Manchester by using a system that
incorporated a Gilson 307 pump operating at 0.3 cm3 mLÀ1 through four
Polymer Labs3m Mixed E columns in tandem followed by a GBC LC1240
differential refractometer for detection.The eluent was chloroform.UV/
visible spectra of solutions were measured using
a Hitachi U-3000
spectrophotometer.Melting points and thermotropic mesophase transi-
tions were determined by using an Olympus BH-2 polarising microscope in
conjunction with a Linkam TMS 92 thermal analyser and a Linkam
THM 600 cell.Differential scanning calorimetry (DSC) was undertaken by
using a Thermal Analyst 2000 in conjunction with a DSC 10 differential
scanning calorimeter from TA Instruments.Silica gel (Merck 7734) was
used in chromatographic separations.TLC was performed using silica gel
(Merck 5554) supported on aluminium sheets.Solvents were dried, where
appropriate, over sodium or calcium hydride and distilled under an
atmosphere of dry nitrogen.
Conclusion
The synthesis of highly substituted 3:1 phthalocyanine deriv-
atives whose substituents include one or two bromine atoms
on one of the benzenoid rings has been achieved.These
compounds have been converted into the corresponding
ethynyl and trimethylsilylethynyl derivatives by Stille and
Sonogashira coupling methods.Oxidative coupling of the
monoethynyl compound provides a butadiynyl-linked binu-
clear phthalocyanine derivative that is isomerically pure.
Under similar conditions, the diethynylphthalocyanine deriv-
ative yielded a mixture of compounds which contains a
diphthalocyaninodehydro[12]annulene as the major product.
It shows a substantial splitting of the Q-band absorption to the
extent that the lower energy component absorbs at 822 nm.
Mass spectrometry provides evidence of self aggregation in
the solution phase.On heating the compound on a hotstage to
about 1108C, it enters a liquid crystal phase.However, on
further heating to 2208C there is an irreversible change arising
from an oligomerisation process, which presumably occurs
through the diyne unit in the annulene ring.A minor product
of the oxidative coupling of the diethynylphthalocyanine has
been identified as the cyclic trimer, a triphthalocyaninodehy-
dro[18]annulene.Compared with the diphthalocyaninodehy-
dro[12]annulene, the compound shows a less strongly split
4,5-Dibromo-3,6-dihydroxyphthalonitrile (6): NBS (7 g, 38.8 mmol) was
added portionwise over 15 min to a stirred solution of 2,3-dicyanohydro-
quinone (3 g, 18.7 mmol) in tert-butyl alcohol (12 mL) at 458C.Stirring was
continued for 2 h and then additional NBS (7 g, 38.8 mmol) was added over
15 min.After a further 2 h, the reaction was cooled to room temperature
and poured into an aqueous solution of sodium metabisulfite (6 g in 60 mL,
excess) at 08C with vigorous stirring.The mixture was stirred for 10 min,
the precipitate filtered and washed with cold water (30 mL).The product
was dried under vacuum at 608C for 24 h to yield 6 as a cream powder
(3.94 g, 66.1%). This was used without further purification, but an
analytical sample was prepared by recrystallisation from acetone/water.
M.p. 2488C (decomp) (literature value 2508C[19]); 13C NMR (270 MHz,
À
À
[D6]acetone): d ˆ 151.74 (C O), 123.08 (C Br), 113.07 (CN), 102.46 (C-
CN); IR (nujol): nÄ ˆ 3250 (br), 2232 cmÀ1 (m); elemental analysis calcd (%)
for C8H2O2N2Br2 (317.92): C 30.22, H 0.63, N 8.81, Br 50.27; found C 30.47,
H 0.42, N 8.70, Br 50.22.
4,5-Dibromo-3,6-dibutoxyphthalonitrile (7): A mixture of compound 6
(2.50 g, 7.86 mmol), triphenylphosphine (4.95 g, 18.9 mmol), and 1-butanol
(1.5 g, 20.2 mmol) was dissolved in dry THF (80 mL) and cooled to 08C.A
solution of diisopropyl azodicarboxylate (4.35 g, 21.5 mmol) in THF
(30 mL) was added dropwise over 30 min.The solution was allowed to
warm to RTand stirred for an additional 10 h.The THF was removed under
reduced pressure to give a dark red oil, which was dissolved in diethyl ether
(20 mL).The solution was filtered to remove undissolved triphenylphos-
3964
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3964 $ 17.50+.50/0
Chem. Eur. J. 2000, 6, No. 21

Phthalocyaninoannulenes
3958±3967
phine oxide, concentrated and separated by column chromatography over
silica (eluent: CH2Cl2/petrol 1:2).The product was recrystallised from
cyclohexane to afford compound 7 as white crystals (2.75 g, 83.6%). M.p.
72 ± 738C; 1H NMR (270 MHz, CDCl3): d ˆ 4.24 (t, J ˆ 6.4 Hz, 4H), 1.92
(quint, J ˆ 7.0 Hz, 4H), 1.67 ± 1.53 (m, 4H), 1.04 (t, J ˆ 7.3 Hz, 6H); 13C
phine)palladium(ii) chloride (7 mg, 10 mmol), copper(I) iodide (2.2 mg,
11.6 mmol) and trimethylsilylamine (TMSA, 25 mg, 255 mmol) were added
in that order and at 10 min intervals to a stirred solution of 3 (40 mg,
23.3 mmol) in dry degassed triethylamine (3.5 mL) under Ar in a dry screw-
cap pressure tube.Under a fast stream of Ar the rubber septum was
removed and the screw-cap sealed; the reaction mixture was heated and
stirred in an oil bath at 1008C for 16 h.The tube was cooled, and further
bis(triphenylphosphine)palladium(ii) chloride (4.1 mg), copper(i) iodide
(1.7 mg) and TMSA (25 mg) were added under Ar. The reaction was
heated at 1008C for a further 12 h.The mixture was cooled, filtered and
concentrated under reduced pressure.The residue was dried at 05. mmHg
for 12 h to remove excess TMSA and triethylamine traces, and further
purified by column chromatography over silica (eluent: petrol/dichloro-
methane 97:3).The first fraction was unreacted starting material (34. mg).
The second fraction contained a mixture; subsequent green fractions
containing minor amounts of material were discarded.The second fraction
was further purified by column chromatography over silica (eluent: petrol/
dichloromethane 98.5:1.5 then 97:3) to afford compound 11 (8.0 mg, 22%)
À
À
(270 MHz, CDCl3): d ˆ 156.37 (ArC O), 129.61 (ArC Br), 112.33 (CN),
109.22 (ArC-CN), 76.43, 31.95, 18.92, 13.73; MS (70 eV, EI): m/z (%): 432
‡
(3.1), 430 (5.2), 428 (3.5) [M] ; IR (nujol): nÄ ˆ 2230 cmÀ1 (m); elemental
analysis calcd (%) for C16H18N2O2Br2 (430.14): C 44.68, H 4.22, N 6.51, Br
37.15; found: C 44.51, H 4.28, N 6.47, Br 37.33.
4-Bromo-3,6-dibutoxyphthalonitrile (8): A mixture of compound 6 (3 g,
9.4 mmol), finely crushed potassium carbonate (3 g, excess) and N,N,N-
tributyl-1-butananinium bromide (TBAB, 0.26 g, 0.7 mmol) was heated
under reflux in MEK (80 mL) for 12 h.The reaction was cooled and
1-iodobutane (3.70 g, 20 mmol) was added. Heating under reflux was
continued for a further 72 h.Upon cooling, the reaction was filtered and
washed with ethyl acetate.The organics were removed under reduced
pressure, and the residue dissolved in ethyl acetate (100 mL).This was
washed with 5% HCl (25 mL), saturated K2CO3 (25 mL), water (25 mL)
and brine (25 mL), dried (MgSO4), filtered and concentrated under
reduced pressure.The crude product was purified by column chromatog-
raphy over silica (eluent: petrol/CH2Cl2 2:1) and recrystallised from
cyclohexane to afford compound 8 (1.43 g, 43%). M.p. 102.5 ± 1048C;
1H NMR (270 MHz, [D6]acetone): d ˆ 7.88 (s, 1H), 4.30 (t, J ˆ 6.4 Hz, 2H),
4.18 (t, J ˆ 6.4 Hz, 2H), 1.86 (m, 4H), 1.56 (m, 4H), 1.00 (t, J ˆ 7.3 Hz, 3H),
0.99 (t, J ˆ 7.3 Hz, 3H); 13C NMR (300 MHz, [D6]acetone): d ˆ 157.68
1
as the first eluted component; H NMR (270 MHz, CDCl3): d ˆ 7.76 (brs,
4H), 7.73 (brs, 2H), 4.63 (t, J ˆ 6.9 Hz, 2H), 4.50 ± 4.39 (m, 6H), 4.34 ± 4.25
(m, 8H), 2.13 ± 1.84 (m, 16H), 1.62 ± 1.03 (m, 88H), 0.96 ± 0.91 (2 Â t, 6H),
0.78 (brt, 18H), 0.42 (s, 9H).
Further elution gave a second fraction and compound 1a (13.2 mg, 35%)
was isolated after recrystallisation from THF/methanol.Mp.69
8C;
1H NMR (270 MHz, CDCl3): d ˆ 7.78 (brs, 4H), 7.75 (s, 2H), 4.60 (t, J ˆ
7.2 Hz, 4H), 4.47 (t, J ˆ 6.9 Hz, 4H), 4.35 ± 4.26 (m, 8H), 2.10 ± 1.90 (m,
16H), 1.60 ± 1.08 (m, 88H), 0.95 (t, J ˆ 7.4 Hz, 6H), 0.80 (t, J ˆ 6.6 Hz,
12H), 0.79 (t, J ˆ 6.6 Hz, 6H), 0.43 (s, 18H); 13C NMR (67.5 MHz, CDCl3):
d ˆ 154.18 (ArCO), 147.99, 139.19, 138.13, 137.77, 134.75, 134.66, 134.43,
À
À
À
(ArC O), 152.80 (ArC O), 124.94, 123.33 (ArC H), 112.81 (CN), 112.69
À
À
(CN), 111.39 (ArC CN), 103.83 (ArC CN), 75.75, 70.40, 31.81, 30.57, 18.70,
‡
18.66, 13.07, 12.98; MS (70 eV, EI): m/z (%): 350.1 (4.8), 352.1 (4.5) [M] ;
IR (nujol): nÄ ˆ 2230 cmÀ1 (m); elemental analysis calcd (%) for
C16H19N2O2Br1 (351.24): C 54.85, H 5.47, N 8.00, Br 22.54; found C 54.71,
H 5.43, N 7.89, Br 22.67.
130.83, 130.47, 130.29, 130.19, 129.16, 128.17, 127.81, 127.47, 104.74 (C CSi),
À
À
100.97 (C CSi), 75.43 (OCH2), 32.66, 32.56, 32.18, 31.88, 31.50, 30.53, 29.90,
29.85, 29.72, 29.67, 29.61, 29.45, 29.31, 22.64, 22.55, 19.37, 14.20, 14.07, 0.20;
UV/Vis (2.80  10À6 m in toluene): lmax (loge) ˆ 732 (4.99), 702 nm (4.95);
1,4-Dibutoxy-2,3-dibromo-8,11,15,18,22,25-hexakis(decyl)phthalocyanin-
ato nickel(ii) (3): Freshly cleaned lithium (ca.50 mg, 75. mmol) was added
to 3,6-didecylphthalonitrile[21] (2.56 g, 6.27 mmol) and 7 (0.30 g, 0.70 mmol)
in refluxing butanol (20 mL) under argon.The reaction was heated under
reflux in the dark for 16 h, cooled, nickel acetate tetrahydrate (0.53 g,
2.1 mmol) was added and heating under reflux was continued for 2 h. After
cooling, the solvents were removed under reduced pressure, and the
residue triturated with methanol to afford a green solid.Purification by
column chromatography over silica (eluent: petrol) afforded 1,4,8,11,15,18,
22,25-octakis(decyl)phthalocyaninato nickel(ii) (0.71 g, 24%) as the first
fraction; changing the eluent to petrol/dichloromethane (1:1) afforded a
second fraction.The latter was further purified by column chromatography
over silica (eluent: petrol/dichloromethane 19:1) to afford 3 (45.7 mg,
3.8%) after recrystallisation from THF/methanol. M.p. 728C (K ! I), 678C
(I ! D), 578C (D ! K); 1H NMR (300 MHz, [D6]benzene): d ˆ 7.82 (s,
4H), 7.81 (s, 2H), 4.75 (t, J ˆ 7.5 Hz, 4H), 4.66 ± 4.57 (3 overlapping t, 12H),
2.34 ± 2.17 (m, 16H), 1.92 ± 1.11 (m, 88H), 0.95 (t, 6H, J ˆ 7.4 Hz), 0.87 ±
0.80 (m, 18H); UV/Vis (3.68  10À6 m in toluene): lmax (loge) ˆ 716 (5.10),
‡
MS (FAB): m/z: isotopic cluster at 1747 [M‡H] ; IR (KBr): nÄ ˆ 2929 (s),
2861 (m), 2155 (w), 1598 (w), 1457 (w), 1200 (w), 1092 cmÀ1 (m).
1,4-Dibutoxy-2,3-di(ethynyl)-8,11,15,18,22,25-hexakis(decyl)phthalocyani-
nato nickel(ii) (1b): Tetrakis(triphenylphosphine)palladium(0) (10.5 mg,
9.0 mmol) was added to a solution of 3 (48.6 mg, 28.3 mmol), anhydrous
lithium chloride (10 mg, 233 mmol) and triphenylphosphine (9.5 mg,
36 mmol) in dry degassed toluene (6 mL) under argon.After stirring for
10 min, tributyl(ethynyl)tin (60 mg, 190 mmol) was added, and the reaction
heated at 1008C for 16 h.The reaction was cooled, and the toluene
removed under reduced pressure.The residue was triturated with acetone
to remove excess tributyl(ethynyl)tin and washed from the filter paper with
THF.The THF was removed under reduced pressure, and the residue was
purified by column chromatography (eluent: petrol/dichloromethane 19:1)
and recrystallised from THF-methanol to afford compound 1b (27.2 mg,
60%).Mp..83 8C (K ! D), 918C (D ! I); 1H NMR (270 MHz, [D6]ben-
zene): d ˆ 7.81 ± 7.78 (m, 6H), 4.83 ± 4.76 (m, 8H), 4.61 ± 4.56 (m, 8H), 3.53
(s, 2H), 2.33 ± 2.21 (m, 16H), 1.93 ± 1.11 (m, 88H), 0.96 (t, J ˆ 7.4 Hz, 6H),
0.92 ± 0.81 (m, 18H); 13C NMR (67.5 MHz, [D6]benzene): d ˆ 154.86,
148.47, 148.40, 142.86, 139.57, 138.37, 138.01, 135.40, 135.31, 131.45, 130.93,
130.89, 130.00, 121.68, 87.63, 80.13, 75.87, 33.23, 32.93, 32.20, 31.16, 31.09,
30.57 ± 29.6, 23.04, 23.01, 19.70, 14.33, 14.26; UV/Vis (2.51 Â 10À6 m in
toluene): lmax (loge) ˆ 729 (4.99), 698 (4.88), 666 (4.44), 628 (4.23) nm; MS
‡
698 (5.03), 636 nm (4.39); MS (FAB): m/z: isotopic cluster at 1716 [M‡H] ;
elemental analysis calcd (%) for C100H150N8O2Br2Ni1 (1715.84): C 70.04, H
8.82, N 6.53; found C 70.40, H 8.90, N 6.30.
Further elution (petrol/dichloromethane 1:1) afforded a second fraction,
and compound 10 (38.2 mg, 3.2%) was isolated after recrystallisation from
THF/methanol.Mp..65 8C (K ! D), 878C (D ! I); 1H NMR (270 MHz,
CDCl3): d ˆ 7.78 (s, 4H), 7.72 (s, 2H), 4.59 ± 4.43 (m, 10H), 4.30 (brt, 8H),
2.13 ± 1.89 (m, 18H), 1.75 ± 1.08 (m, 90H), 0.95 (t, 3H), 0.91 (t, 3H), 0.85 ±
0.76 (brt, 21H); 13C NMR (67.5 MHz, CDCl3): d ˆ 151.73, 149.58, 147.39,
147.35, 147.26, 147.12, 146.81, 145.57, 143.49, 143.06, 139.05, 137.88, 137.70,
134.59, 134.41, 134.36, 130.66, 130.60, 130.21, 130.21, 129.69, 125.52, 117.00,
75.31 (OCH2), 75.04 (OCH2), 74.54 (OCH2), 32.69, 62.62, 32.38, 32.33,
32.19, 32.11, 32.01, 31.84, 31.75, 31.45, 30.59, 30.44, 30.23, 30.17, 30.03, 29.89,
29.72, 29.64, 29.60, 29.44, 29.33, 29.29, 22.63, 19.52 (OCH2CH2CH2), 19.34
(OCH2CH2CH2), 19.19 (OCH2CH2CH2), 14.10, 14.04; UV/Vis (1.92 Â
10À6 m in toluene): lmax (loge) ˆ 714 (5.21), 694 (sh), 636 nm (4.57); MS
‡
(FAB): m/z: isotopic cluster at 1606 [M‡H] ; elemental analysis calcd (%)
for C104H152N8O2Ni1 ´ CH3OH (1637.14): C 77.03, H 9.60, N, 6.84; found C
76.99, H 9.56, N 6.98.
1,4-Dibutoxy-2,3-di(ethynyl)-8,11,15,18,22,25-hexakis(decyl)phthalocyani-
nato nickel(ii) (1b) from 1a: Potassium hydroxide solution (0.1 mL of a
solution containing 1 flake in 0.5 mL of H2O) was added to a solution of 1a
(9.2 mg, 5.3 mmol) in THF (5 mL) and methanol (1 mL), and the reaction
was stirred under Ar in the dark for 12 h.One drop of 5% HCl was added,
and the solvents were removed under reduced pressure.The residue was
triturated with methanol and further purified by column chromatography
over silica (eluent: petrol/dichloromethane 10:1) to afford 1b as a green
solid (6.7 mg, 79%) identical to the sample obtained above.
‡
(FAB): m/z: isotopic cluster at 1635 [M À OC4H9] ; MS (MALDI): m/z:
‡
1707 [M À H] ; elemental analysis calcd (%) for C104H159N8O3Br1Ni1 ´
1,4-Dibutoxy-2-bromo-8,11,15,18,22,25-hexakis(decyl)phthalocyaninato
nickel(ii) (4): Compound 4 was prepared from a mixed cyclotetramerisation
of 8 and 9 (R ˆ decyl) by using the method which afforded 3 above.Yield
4%.Mp..30 8C (K ! D), 1068C (D ! I); 1H NMR (300 MHz, [D6]ben-
CH3OH (1740.09): C 72.48, H 9.44, N 6.44; found C 72.04, H 9.12, N 6.49.
1,4-Dibutoxy-2,3-(2'-trimethylsilylethynyl)-8,11,15,18,22,25-hexakis(de-
cyl)phthalocyaninato nickel(ii) (1a) and compound 11: Bis(triphenylphos-
Chem. Eur. J. 2000, 6, No. 21
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3965 $ 17.50+.50/0
3965

M.J.Cook, M.J.Heeney
FULL PAPER
zene): d ˆ 7.82 (brs, 4H), 7.77 (s, 2H), 7.68 (s, 1H), 4.83 ± 4.78 (brt, 4H),
4.66 (t, J ˆ 7.0 Hz, 2H), 4.63 ± 4.57 (2  t, 8H), 4.22 (t, J ˆ 6.8 Hz, 2H),
2.34 ± 2.22 (m, 14H), 2.13 (quint, J ˆ 7.2 Hz, 2H), 1.93 ± 1.10 (m, 88H), 0.99
(t, J ˆ 7.4 Hz, 3H), 0.91 ± 0.76 (m, 21H); 13C NMR (67.5 MHz, CDCl3) d
151.54, 147.74, 147.67, 147.46, 147.13, 146.70, 146.52, 143.68, 142.61, 139.03,
138.94, 137.93, 137.70, 137.66, 134.84, 134.77, 134.70, 134.65, 134.47, 134.38,
130.87, 130.28, 130.17, 130.10, 125.19, 119.52, 116.37, 75.10 (OCH2), 69.76
(OCH2), 32.74, 32.62, 32.31, 32.15, 31.86, 31.81, 31.65, 31.48, 31.16, 30.46,
30.26, 29.90, 29.80, 29.71, 29.65, 29.62, 29.45, 29.36, 29.29, 29.24, 22.63, 22.57,
19.45, 19.36, 14.05; UV/Vis (3.37  10À6 m in toluene): lmax (loge) ˆ 714
(5.10), 700 (sh), 635 nm (4.47); elemental analysis calcd (%) for
C100H151N8O2Br1Ni1 (1635.95): C 73.42, H 9.30, N 6.85; found C 74.08, H
9.52, N 6.19.
The second fraction was collected and recrystallised once from THF-
acetone and once from THF-methanol to afford the triphthalocyaninode-
hydro[18]annulene 15 (3.2 mg, 8%) admixed with about 10% (by 1H NMR)
of 14.For 15, 1H NMR (270 MHz, [D6]benzene, 458C): d ˆ 7.95 (d, J ˆ
8.1 Hz, 6H), 7.87 (d, J ˆ 8.1 Hz, 6H), 7.85 (s, 6H), 5.12 (t, 12H), 5.00 ± 4.88
(m, 12H), 4.70 ± 4.57 (m, 24H), 2.45 ± 2.15 (m, 48H), 2.02 ± 1.08 (m, 264H),
‡
1.05 ± 0.82 (m, 72H); MS (MALDI): m/z: isotopic cluster at 4809 [M‡H] ;
UV/Vis (3.22  10À5 m in toluene) lmax ˆ 780, 698 nm.
Acknowledgements
We thank EPSRC for a CASE studentship (with DERA) for MJH during
part of this work, the EPSRC Mass Specrometry Service at Swansea for
FAB mass spectra, Ms.V.Boote at University of Manchester for running
MALDI-TOF mass spectra, Dr.Helen Cooper at Warwick University for
providing FT-ICR electrospray mass spectra and for helpful discussions,
and Dr.N.B.McKeown and Dr H.Li, University of Manchester, for
assistance with GPC separations.
1,4-Dibutoxy-2-(2'-trimethylsilylethynyl)-8,11,15,18,22,25-hexakis(de-
cyl)phthalocyaninato nickel(ii) (2 a): Compound 2a was prepared from 4 by
following the procedure for 1a above using dry THF/Et3N (5:1) as solvent.
Yield (62%).Mp..46
8C (K ! D), 113oC (D ! I); 1H NMR (270 MHz,
[D8]toluene): d ˆ 7.81 (s, 6H), 7.65 (s, 1H), 4.86 ± 4.78 (brt, 6H), 4.68 ± 4.58
(2 Â t, 8H), 4.26 (brt, 2H), 2.38 ± 2.20 (m, 16H), 1.90 ± 1.10 (m, 88H), 0.99 ±
0.76 (m, 24H), 0.49 (s, 9H); UV/Vis (3.44  10À6 m in toluene): lmax (loge) ˆ
722 (5.09), 700 (5.02), 640 (4.43), 346 nm (4.59); MS (FAB): m/z: isotopic
‡
cluster at 1653 [M‡H] ; elemental analysis calcd (%) for C105H160N8O2Si1-
Ni1 (1653.25): C 76.28, H 9.75, N 6.78; found C 76.95, H 9.67, N 6.84.
[1] See, for example: N.B. McKeown, Phthalocyanine Materials: Syn-
thesis, Structure and Function. Cambridge University Press, Cam-
bridge, 1998; PhthalocyaninesÐProperties and Applications, Vols. 1 ±
1,4-Dibutoxy-2-(ethynyl)-8,11,15,18,22,25-hexakis(decyl)phthalocyaninato
nickel(ii) (2 b:) Compound 2b was prepared from 4 by following the
procedure used to prepare 1b above.Yield (48%).Mp..36
8C (K ! D),
4 (Eds.: C.C.Leznoff, A.B.P.Lever), VCH, New York,
1996; M.Hanack, H.Heckmann, R.Polley, Methods in Organic
Chemistry (Houben-Weyl), Vol. E9d (Ed.: E. Schaumann), Georg
Thieme, Stuttgart, 1998.
1989, 1993,
131oC (D ! I); H NMR (270 MHz, [D6]benzene): d ˆ 7.81 ± 7.78 (m, 6H),
7.75 (s, 1H), 4.87 ± 4.82 (m, 6H), 4.66 ± 4.55 (m, 8H), 4.27 (t, J ˆ 7.0 Hz, 2H),
3.28 (s, 1H), 2.31 ± 2.23 (m, 16H), 1.98 ± 1.06 (m, 88H), 0.99 (2 Â t, 6H),
0.94 ± 0.77 (m, 18H); UV/Vis (5.20  10À6 m in toluene): lmax (loge) ˆ 721
(5.07), 701 (5.01), 641 (4.39), 347 nm (4.54); IR (KBr): nÄ ˆ 3304 (m), 2965
(sh), 2927 (s), 2853 (s), 1468 (m), 1318 (m), 1187 (m), 1102 cmÀ1 (m);
elemental analysis calcd (%) for C102H152N8O2Ni1 (1518.07): C 77.49, H 9.69,
N 7.09; found C 77.80, H 9.68, N 7.09.
1
[2] F.H.Moser, A.L.Thomas, The Phthalocyanines, Vol. 2 Manufacture
and Applications, CRC Press, Boca Raton, FL 1983.
[3] P.Gregory, High-Technology Applications of Organic Colorants,
Plenum, New York, 1991; P.Gregory, J. Porphyrins Phthalocyanines
2000, 4, 432 ± 437.
[4] J.E.Kuder, J. Imaging Sci. 1988, 32, 51 ± 56; R.Ao, L.Külmmerl, D.
Haarer, Adv. Mater. 1995, 7, 495 ± 499; D.Birkett, Chem. Ind. 2000,
178 ± 181.
[5] J.D.Wright, Prog. Surf. Sci. 1989, 31, 1 ± 60; A.W.Snow, W.R.Barger
in PhthalocyaninesÐProperties and Applications (Eds.: C. C. Leznoff
A.B.P.Lever), VCH, New York, 1989, pp.341 ± 392.
[6] D.Wöhrle, D.Meissner, Adv. Mater. 1991, 3, 129 ± 138; H.Eichhorn, J.
Porphyrins Phthalocyanines 2000, 4, 88 ± 102.
One pot conversion of 2a, via 2b, into 1,4-bis-2[(1,4-dibutoxy-
8,11,15,18,22,25-hexakis(decyl)phthalocyaninato nickel(ii)]butadiyne (12):
A solution of 2a (46 mg, 27.8 mmol), anhydrous copper(ii) acetate (200 mg,
1.1 mmol) and finely crushed K2CO3 (210 mg, 1.5 mmol) in dry pyridine/
methanol/THF (1:1:3, 10 mL) was stirred under Ar at 558C for 16 h.The
reaction was cooled, filtered and washed with THF until the washings were
colourless.The filtrate was concentrated under reduced pressure, and the
Pc was redissolved in THF and filtered to remove copper salts.The crude
product was concentrated and purified by column chromatography over
silica (eluent: petrol/dichloromethane/Et3N 95:5:0.1). The first fraction was
concentrated and recrystallised from THF/methanol to afford compound
12 (27 mg, 61%).Mp..159 8C; 1H NMR (270 MHz, [D6]benzene, 508C):
d ˆ 7.87 ± 7.83 (m, 12H), 7.74 (s, 2H), 5.03 (t, J ˆ 6.9 Hz, 4H), 4.91 ± 4.86 (m,
8H), 4.66 ± 4.59 (m, 16H), 4.46 (t, J ˆ 7.1 Hz, 4H), 2.46 ± 2.22 (m, 32H),
1.97 ± 1.04 (m, 176H), 0.89 ± 0.80 (m, 48H); UV/Vis (4.94 Â 10À6 m in
toluene): lmax (loge) ˆ 752 (5.43), 702 (5.27), 634 (4.71), 438 (4.52), 353
[7] H.S.Nalwa, J.S.Shirk in
PhthalocyaninesÐProperties and Applica-
tions, Vol. 4 (Eds.: C.C.Leznoff and A.B.P.Lever), VCH Publishers,
NY, 1996, pp.79 ± 181; J.S. Shirk, R.G.S. Pong, S.R. Flom, H.
Heckmann, M.Hanack, J. Phys. Chem. 2000, 104, 1438 ± 1449.
[8] L.Milgrom, S.MacRobert, Chem. Br. 1998, 45 ± 50; E.A.Lukꢁyanets,
J. Porphyrins Phthalocyanines 1999, 3, 424 ± 432; H.Ali, J.E.van Lier,
Chem. Rev. 1999, 99, 2379 ± 2450.
Á
[9] D.Delie vre, O.Damette, J.Simon, J. Chem. Soc. Chem. Commun.
1993, 939 ± 940; N.Kobayashi, H.Lam., W.A.Nevin, P.Janda, C.C.
Leznoff, T.Koyama, A.Monden, H.Shirai, J. Am. Chem. Soc. 1994,
116, 879 ± 890; C.C.Leznoff, H.Lam, S.M.Marcuccio, W.A.Nevin, P.
‡
(4.95), 307 nm (5.06); MS(MALDI): m/z: isotopic cluster at 3161 [M ‡ H] ;
IR (KBr): nÄ ˆ 2960 (sh), 2919 (s), 2848 (s), 1606 (m), 1526 (m), 1468 (m),
1181 (m), 1096 cmÀ1 (s); elemental analysis calcd (%) for C204H302N16O4Ni2
(3160.13): C 77.54, H 9.63, N 7.09; found C 77.14, H 9.50, N 6.90.
Janda, N.Kobayashi, A.B.P.Lever,
J. Chem. Soc. Chem. Commun.
Á
Â
, F.
1987, 699 ± 701; D.Delie vre, L.Bosio, J.Simon, JJ..Andre
Oxidative coupling of 1b to give 14 and 15: Copper(ii) acetate (180 mg,
0.1 mmol) was added to a solution of 1b, (39.0 mg, 24.3 mmol) in dry THF/
pyridine/methanol (1:1:0.25, 45 mL). The solution was stirred in the dark
under Ar for 8 h at 808C.The reaction was cooled, filtered and washed with
THF.The solution was concentrated under reduced pressure and filtered
through silica (eluent: petrol/THF 9:1).The solution was concentrated
under reduced pressure and further purified by column chromatography
(eluent: petrol/THF 19:1); the fractions were analysed by UV-visible
spectrometry.The first fraction was collected and recrystallised from THF-
methanol to afford the diphthalocyaninodehydro[12]annulene 14 (9.5 mg,
24%). 1H NMR (270 MHz, [D6]benzene, 408C): d ˆ 7.86 ± 7.80 (m, 12H),
4.91 (t, 8H), 4.80 ± 4.72 (m, 8H), 4.68 ± 4.56 (m, 16H), 2.35 ± 2.18 (m, 32H),
1.95 ± 1.12 (m, 176H), 1.02 ± 0.84 (m, 48H); MS (MALDI): m/z: isotopic
Bensebaa, J. Am. Chem. Soc. 1992, 114, 4475 ± 4479; J.Yang, M.R.
Van de Mark, Tetrahedron Lett. 1993, 34, 5223 ± 5226; N.Kobayashi,
Y.Higashi, T.Osa, J. Chem. Soc. Chem. Commun. 1994, 1785 ± 1786;
G.de la Torre, MV. .Martínez-Díaz, P.Ashton, T.Torres,
J. Org.
Chem. 1998, 63, 8888 ± 8893; G.de la Torre, M.V.Martínez-Díaz, T.
Torres, J. Porphyrins Phthalocyanines 1999, 3, 560 ± 568.
[10] D.S.Terekhov, K.J.M.Nolan, C.R.McArthur, C.C.Leznoff,
Chem. 1996, 61, 3034 ± 3040.
J. Org.
[11] H.Ali, J.E.van Lier, Tetrahedron Lett. 1997, 38, 1157 ± 1160.
[12] H.Isago, D.S.Terekhov, C.C.Leznoff, J. Porphyrins Phthalocyanines
1999, 1, 135 ± 140; C.C.Leznoff, Z.Li, H.Isago, A.M.DꢁAscanio,
D.S.Terekhov, J. Porphyrins Phthalocyanines 1999, 3, 406 ± 416.
Â
[13] E.M.Maya, P.Va zquez, T.Torres, Chem. Commun. 1997, 1175 ± 1176;
‡
Â
cluster at 3206 [M‡H] ; HRMS (FT-ICR): calcd for C208H300N16O4Ni2
E.M.Maya, P.Va zquez, T.Torres, Chem. Eur. J. 1999, 5, 2004 ± 2013;
1601.1235 [M]2‡; found 1601.1211; UV/Vis (2.81  10À5 m in toluene): lmax
(loge) ˆ 822 (5.32), 691 nm (4.93).
E.M.Maya, P.Va zquez, T.Torres, L.Gobbi, F.Diederich, S.Pyo, L.
Â
Echegoyen, J. Org. Chem. 2000, 65, 823 ± 830.
3966
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3966 $ 17.50+.50/0
Chem. Eur. J. 2000, 6, No. 21

Phthalocyaninoannulenes
3958±3967
Â
Â
Â
[14] G.de la Torre, P.Va zquez, F.Agullo -Lopez, T.Torres, J. Chem. Mater.
[23] K.Sonogashira, Y.Tohda, Y., N.Hagihara, N. Tetrahedron Lett. 1975,
16, 4467 ± 4470; S.Thorand, N.Krause, J. Org. Chem. 1999, 63, 8551 ±
8553.
1998, 8, 1671 ± 1683.
[15] T.Nishinaga, T.Kawamura, K.Komatsu,
J. Org. Chem. 1997, 62,
5354 ± 5362; M.M.Haley, M.L.Bell, S.C.Brand, D.B.Kimball, J.J.
Pak, W.B.Wan, Tetrahedron Lett. 1997, 38, 7483 ± 7486; W.B.Wan,
D.B.Kimball, M.M.Haley, Tetrahedron Lett. 1998, 39, 6795 ± 6798; T.
Nishinaga, H.Nakayama, N.Nodera, K.Komatsu, Tetrahedron Lett.
1998, 39, 7139 ± 7142; UH. F..Bunz, G.Roidl, M.Altmann, V.
Enkelmann, K.D. Shimizu, J. Am. Chem. Soc. 1999, 121, 10719 ±
10726.
[24] D.E.Rudisill, J.K.Stille, J. Org. Chem. 1989, 54, 5856 ± 5866.
[25] N.Kobayashi, H.Konami, PhthalocyaninesÐProperties and Applica-
tions, Vol. 4 (Eds.: C.C.Leznoff, A.B.P.Lever), VCH,
1996, pp.343 ±
404.
[26] A.J. Matzger, K.P.C. Vollhardt,
6794.
Tetrahedron Lett. 1998, 39, 6791 ±
[27] A.S.Cherodian, A.N. Davies, R.M.Richardson, M.J. Cook, N.B.
McKeown, A.J.Thomson, J.Feijoo, G.Ungar, K.J.Harrison,
[16] Q.Zhou, P.Carroll, T.Swager, J. Org. Chem. 1994, 59, 1294 ± 1301;
K.P.Baldwin, A.J.Matzger, D.A.Scheiman, C.A.Tessier, K.P.C.
Vollhardt, W.J. Youngs, Synlett. 1995, 1215 ± 1218; J.J. Pak, T.J.R.
Weakley, M.M. Haley, J. Am. Chem. Soc. 1999, 121, 8182 ± 8192;
Mol.
Cryst. Liq. Cryst. 1991, 196, 103 ± 114; M.J.Cook, S.J.Cracknell, K.J.
Harrison, J. Mater. Chem. 1991, 1, 703 ± 704; A.V. Belushkin, M.J.
Cook, D.Frezzato, S.D.Haslam, A.Ferrarini, D.Martin, J.McMurdo,
U.H.F.Bunz, V.Enkelmann,
[17] M.J.Cook, I.Chambrier, S.J.Cracknell, D.A.Mayes, D.A.Russell,
Chem. Eur. J. 1999, 5, 263 ± 266.
P.L. Nordio, R.M. Richardson, A. Stafford,
593 ± 607.
Mol. Physics 1998, 93,
Photochem. Photobiol. 1995, 62, 542 ± 545.
[18] J.Bakboord, M.J.Cook, E.Hamuryudan,
[28] A.N.Cammidge, M.J.Cook, K.J.Harrison, A.J.Thomson,
Soc. Perkin Trans. 1 1991, 3053 ± 3058.
J. Chem.
J. Porphyrins Phthalocya-
nines 2000, in press.
[29] I.Chambrier, M.J.Cook, S.J.Cracknell and J.McMurdo
J. Mater.
[19] T.Guenther, Justus Liebigs Ann. Chem. 1906, 349, 56 ± 58.
[20] Roussel UCLFA, Fr Patent 1313082, Dec.28, 1962 [Chem Abs. 1962,
57, 11283h].
Chem. 1993, 3, 841 ± 849; M.J . Cook, J. McMurdo, D. A. Miles, R. H.
Poynter, J.M.Simmons, S.D.Haslam, R.M.Richardson, K.Welford,
J. Mater. Chem. 1994, 4, 1205 ± 1213.
[21] N.B.McKeown, I.Chambrier, M.J.Cook, J. Chem. Soc. Perkin Trans.
1 1990, 1169 ± 1177.
[30] Polydiacetylenes: Synthesis, Structure and Electronic Properties (Eds.:
D.Bloor, R.R.Chance), Martinus Jihoff, 1985.
[22] M.J.Cook, A.J.Dunn, S.D.Howe, A.J.Thomson,
J. Chem. Soc.
Perkin Trans. 1 1988, 2453 ± 2458.
Received: March 29, 2000 [F2393]
Chem. Eur. J. 2000, 6, No. 21
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0947-6539/00/0621-3967 $ 17.50+.50/0
3967