First synthesis of symmetrical and unsymmetrical conjugated trinuclear phthalocyanines covalently linked by ethynyl bridges

Article abstract of DOI:10.1055/s-2006-951547

For the first time, symmetrical and unsymmetrical π-electron-conjugated trinuclear phthalocyanines (Pcs) were synthesized with the Pc units connected directly by ethynyl linkages. Symmetrically alkoxy-substituted bridged ethynylphthalocyanmatozinc(II) tri

Full text of DOI:10.1055/s-2006-951547

LETTER
3231
First Synthesis of Symmetrical and Unsymmetrical Conjugated Trinuclear
Phthalocyanines Covalently Linked by Ethynyl Bridges
C
onjugated Trin
v
uclear Phtha
a
locyanines Linke
M
d
by Ethynyl Bridges . García-Frutos, David D. Díaz, Purificación Vázquez,* Tomás Torres*
Departamento de Química Orgánica (C-I), Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain
Fax +34(91)3973966; E-mail: tomas.torres@uam.es
Received 28 August 2006
bridged bisphthalocyaninato complexes, followed by the
Abstract: For the first time, symmetrical and unsymmetrical p-
electron-conjugated trinuclear phthalocyanines (Pcs) were syn-
thesized with the Pc units connected directly by ethynyl linkages.
Symmetrically alkoxy-substituted bridged ethynylphthalocyanina-
synthesis of novel unsymmetrical substituted push–pull
Pcs with a reversal of substitution pattern, characterized
by the presence of one electron-donor 4-(dimethylami-
tozinc(II) triad was prepared by direct Sonogashira cross-coupling no)phenylethynyl unit and six strong acceptor alkylsulfo-
reaction between suitable diiodo Pc and alkynyl Pc derivatives.
nyl substituents, which showed an unusually strong dipole
Nevertheless, the synthesis of the Pc-based triad having a donor–
moment and very large second-order nonlinear respons-
acceptor electron character was carried out by means of co-cyclo-
es.6 In the present paper, and as a continuation of our in-
tetramerization of two different phthalonitriles, namely 4,5-bis(pro-
terest in the preparation of Pc-containing systems with
pylsulfonyl)phthalonitrile and 4,5-[hexa(butoxy)ethynylphthalo-
extended conjugation using double and triple bonds as
linkers,7 we report on the synthesis and characterization of
the first triads containing merely metallophthalocyanine
(MPc) moieties with a direct triple bond linkage between
the macrocycles that fully conjugates the three major p
systems.8,9 To the best of our knowledge, this is the first
report on the synthesis of this kind of Pc-based triads.
cyaninatozinc(II)]phthalonitrile in the presence of a cobalt(II) salt.
Key words: phthalocyanines, triad, ethynyl, Sonogashira reaction
Many photoactive molecular architecture, such as dyads,
triads, and higher order arrays, have been designed and
studied in recent years as model systems to process effi-
ciently solar energy and, thereby, replicate the natural an-
alogue.1 Under selective light illumination of a given
chromophore, such multicomponent systems are able to
undergo directional electron and/or energy transfer. The
level of electronic communication, both in the ground and
excited state, between the individual components is most-
ly dependent upon the nature of the bridge, which con-
nects the different interacting centers. The role played by
the spacer is also structural, since its chemical nature de-
termines the flexibility or rigidity of the system. It is cru-
cial that the multicomponent system is rigid, so as to
ensure good geometrical control and favor long-lived
charge-separated states. The connector must also be am-
ply versatile to enable construction of different molecular
systems concerning size, shape, composition, and organi-
zation.
Equation 1 outlines the preparation of the symmetrically
substituted Pc-based triad 5 via palladium(II)-catalyzed
Sonogashira cross-coupling reaction.
Interestingly, the reaction between diiodo Pc 1 and ethy-
nyl Pc 2 proceeded in better yields than the one between
diethynyl Pc 3 and iodo Pc 4 under the same conditions.
As shown in Table 1, the best yields for the Sonogashira
cross-coupling between 1 and 2 were obtained by making
use of Pd(PPh3)2Cl2 as catalyst in presence of copper io-
dide and an amine base (entries 1 and 6). The addition of
an excess of potassium iodide improved significantly the
yield of the reaction (entry 1). Moreover, a modified So-
nogashira cross-coupling reaction under copper- and/or
amine-free conditions allowed the formation of the de-
sired triad in ca. 17–28% yield (entries 2, 5, 7, 8 and 9).
Lower yields were achieved using a copper- and ligand-
free coupling catalyzed by Pd(0) under ultrasound irradi-
ation (entries 3 and 4). Interestingly, indium trichloride
was found to work as catalyst for the cross-coupling reac-
tion in N,N-dimethylformamide albeit in very low yield
(entry 10). UV–visible spectrum of triad 5 resulted to be
virtually identical to its iodo Pc 4 and ethynyl Pc 2 precur-
sors (B-band at 356 nm; Q-band at 681 nm).
Since it has been suggested that unsymmetrically substi-
tuted phthalocyanines (Pcs) having suitable donor and ac-
ceptor groups should exhibit second-order nonlinear
optical (NLO) responses and optical limiting behavior,2
some research effort has been carried out in order to study
non-centrosymmetric peripherally substituted Pcs for this
particular purposes,3 but the synthetic challenge of devel-
oping new Pc-based targets capable of displaying efficient
intramolecular charge-transfer remains open. In this line,
we first described the preparation of homo- and heterodi-
metallic ethynyl-,4 butadiynyl-,4 and diethynylethene5
It is worth mentioning that the Pc-containing phosphoni-
um salt 6 (Equation 2) can also be isolated during some of
the tested conditions in low yields (usually <10%). This
product is formed by oxidative addition of the PPh3 ligand
to iodo Pc 4 at high temperature, which is in good agree-
ment with our previous observations.10 In fact, 6 was eas-
ily obtained in 39% yield by reaction of iodozinc(II) Pc 4
with stoichiometric amounts of Pd(PPh3)2Cl2 in N,N-di-
SYNLETT 2006, No. 19, pp 3231–3236
0
1
.1
2
.2
0
0
6
Advanced online publication: 23.11.2006
DOI: 10.1055/s-2006-951547; Art ID: G28506ST
© Georg Thieme Verlag Stuttgart · New York

3232
E. M. García-Frutos et al.
LETTER
RO
OR
RO
OR
N
N
N
N
N
N
RO
RO
OR
OR
X
Y
Z
M1
N
N
+
N
M2
N
N
N
H
N
N
N
N
Pd(PPh3)2Cl2
CuI, KI
Et3N, DMF
80 °C, 48 h
RO
OR
RO
OR
1: X = Y = I; M1 = Zn; R = n-Bu
2: Z = C≡CH; M2 = Zn; R = n-Bu
3: X = Y = C≡CH; M1 = Zn; R = n-Bu
4: Z = I; M2 = Zn; R = n-Bu
OR
RO
OR
RO
N
N
N
N
OR
RO
M2
N
N
N
N
OR
OR
N
N
N
OR
OR
RO
RO
N
M1
N
N
N
N
N
N
N
N
M2
OR
RO
N
N
N
5: M1 = M2 = Zn; R = n-Bu
N
RO
1 (1.0 equiv) + 2 (3.1 equiv)
3 (1.0 equiv) + 4 (3.1 equiv)
5 (39% yield)
5 (28% yield)
OR
RO
OR
Equation 1 Synthesis of symmetrical ethynyl Pc-based triad 5.
methylformamide at 100 °C and in absence of 3. UV–vis- Thus, bisPc complex 8 was prepared under typical Sono-
ible spectrum of 6 showed a split Q-band (two maxima at gashira reaction conditions (Equation 3) using 4,5-diethy-
667 nm and 713 nm) and a remarkable bathochromic shift nylphthalonitrile (7), which is easily accessible from the
with respect to 4 (single Q-band at 681 nm), as a conse- appropriate 4,5-diiodophthalonitrile in two steps.1,3 Thus,
quence of its electronic asymmetry. B-Bands of both the cross-coupling reaction between an excess of io-
MPcs appear in the UV region at about 356 nm.
dozinc(II) Pc 4 and 4,5-diethynylphthalonitrile (7) in tri-
ethylamine with Pd(PPh3)2Cl2 and copper iodide as
catalyst at 90 °C under argon produced 8 in a modest 27%
isolated yield, which showed a nearly identical UV-visi-
ble spectrum to its ethynyl precursor 4.
Unfortunately, all the efforts done to apply this strategy to
the synthesis of donor–acceptor systems by varying the
electronic nature of one of the substituted MPc [diethy-
nylzinc(II) Pc 3 + iodo(hexaalkylsulfonyl)M(II) Pc (M =
Co, Ni);6 ethynylzinc(II) Pc 2 + diiodo(hexaalkylsulfo- Mixed condensation of 4,5-di[ethynylzinc(II) Pc]phtha-
nyl)zinc(II) Pc] were totally fruitless, presumably by un- lonitrile 8 with 4,5-bis(propylsulfonyl)phthalonitrile (9)
favorable electronic effects. At this point and inspired by (8/9 = 1:3) in the presence of the corresponding cobalt(II)
Bayir11 and Ng’s12 works, we decided to employ a differ- salt afforded the desired triad 10 in 11% isolated yield
ent strategy to achieve the unsymmetrical triad, consisting (Equation 4). Some futile experiments with different mo-
in the preparation of two different phthalonitriles deriva- lar ratios were carried out to raise the yield of the triad.
tives and subsequent co-cyclotetramerization in the pres- The unsymmetrical triad was separated by column chro-
ence of the suitable metal(II) salt.
matography from the corresponding totally symmetrical
octa(propylsulfonyl)phthalocyanine derivative formed in
Synlett 2006, No. 19, 3231–3236 © Thieme Stuttgart · New York

LETTER
Conjugated Trinuclear Phthalocyanines Linked by Ethynyl Bridges
3233
Table 1 Survey of Conditions for a Pd-Mediated Cross-Coupling Reaction between Diiodo Pc 1 and Ethynyl Pc 2
Entry
Experimental conditionsa,b
Yield of 3 (%)c
1
2
Pd(PPh3)2Cl2 (0.6 equiv), CuI (0.6 equiv), KI (20 equiv), Et3N–DMF (1:5), 80 °C, 48 h
Pd(PPh3)2Cl2 (1.0 equiv), TBAF (40 equiv), 80 °C, 24 h
39
28
11
21
26
30
25
27
17
4
3
PdCl2 (0.5 equiv), Et3N, acetone, ultrasound irradiation (50 kHz), 30 °C, 2 h
PdCl2 (0.5 equiv), Et3N, [bbim]BF4, ultrasound irradiation (50 kHz), 30 °C, 4 h
Pd(PCy3)2Cl2 (0.6 equiv), Cs2CO3 (6 equiv), DMSO, 90 °C, 48 h
Pd(PPh3)2Cl2 (0.5 equiv), CuI (0.5 equiv), DIPEA, 1,4-dioxane, 70 °C, 24 h
Pd(PPh3)4 (0.4 equiv), piperidine, 60 °C, 48 h
4
5
6
7
8
Pd2(dba)3 (0.4 equiv), AsPh3 (0.2 equiv), Et3N–toluene (5:1), 60 °C, 7 h
Pd(OAc)2 (0.5 equiv), Bu4NOAc (6 equiv), DMF, r.t., 72 h
InCl3 (0.3 equiv), DMF, 90 °C, 48 h
9
10
11
Pd(PPh3)2Cl2 (0.6 equiv), CuI (0.6 equiv), Et3N, THF, r.t., 72 h
18
a All reactions [1 (1.0 equiv) + 2 (3.1 equiv)] were performed in degassed solvents under an argon atmosphere. The amount of each compo-
nent is referred to 1.
b Notes: (i) In general, reactions performed at r.t. usually suffered a loss of ca. 15% in yield compared to those performed at 60–100 °C, even
with longer reaction times. (ii) Variation of overall concentration did not dramatically affect the results. (iii) In all cases, much higher quan-
tities of Pd catalyst were somehow needed compared to a standard Sonogashira cross-coupling between terminal alkynes and aryl halides.
The use of only 2–3 mol% of Pd catalyst gave null or <5% yields.
c Yields of isolated, analytically pure product.
the statistical condensation. The unsymmetrical phthalo- MPcs, and (b) mixed condensation of a suitable 4,5-
cyanine-based triad showed good solubility in organic di[ethynylzinc(II) Pc]phthalonitrile with 4,5-bis(alkyl-
solvents such as chloroform and tetrahydrofuran. UV-vis- sulfonyl)phthalonitrile in the presence of cobalt(II) salt.
ible spectrum of triad 10 showed a bathochromic shift in The latter strategy technically allows the preparation of
the Q-band (two maxima at 695 nm and 673 nm) of ca. 10 the triads with a push–pull electron character and further
nm with respect to 8.
studies concerning the NLO properties of such and other
related systems will be reported in the due course. In
addition to other combinations of metallic centers and
peripheral substituents that may allow for fine-tuning the
physical properties of these compounds, their 1,2-
bisphenylethynylbenzene core opens up new chemical
possibilities to such modified macrocyclic structures.14
In summary, novel symmetrical and unsymmetrical p-
electron-conjugated trinuclear Pcs with the Pc units
connected by direct ethynyl linkages have been prepared
in modest yields following two different strategies: (a)
palladium-catalyzed Sonogashira cross-coupling reaction
between appropriate ethynyl- and halide-substituted
RO
OR
RO
RO
N
N
N
I
RO
RO
N
P
Pd(PPh3)2Cl2
N
N
M2
N
N
N
DMF, 100 °C, 24 h
M2
I
N
N
N
N
RO
N
N
N
RO
OR
OR
6 (39% yield)
RO
OR
4
M2 = Zn, R = n-Bu
Equation 2 Synthesis of Pc-containing phosphonium salt 6.
Synlett 2006, No. 19, 3231–3236 © Thieme Stuttgart · New York

3234
E. M. García-Frutos et al.
LETTER
RO
OR
RO
OR
N
N
N
N
M2
N
N
N
N
RO
CN
CN
RO
CN
+
Pd(PPh3)2Cl2
4
CuI, Et3N
90 °C, 48 h
(4.0 equiv)
CN
7
RO
(1.0 equiv)
8
N
RO
M2 = Zn, R = n-Bu
N
(27 % yield)
N
N
M2
N
N
N
OR
N
OR
RO
RO
Equation 3 Synthesis of 4,5-[diethynylphthalocyaninatozinc(II)]phthalonitrile 8.
NC
SO2R'
SO2R'
8
+
M
2 = Zn, R = n-Bu
NC
9 R' = n-Pr
.
CoCl2 6H2O
DMAE
OR
reflux, 24 h
RO
OR
RO
N
N
N
N
SO2R'
R'O2S
M2
N
N
N
N
OR
OR
N
N
N
OR
R'O2S
R'O2S
N
N
M3
N
OR
N
N
N
N
N
N
M2
SO2R'
R'O2S
N
N
N
10
N
RO
M2 = Zn, R = n-Bu
M3 = Co, R' = n-Pr
OR
RO
(11% yield)
OR
Equation 4 Synthesis of unsymmetrical ethynyl Pc-based triad 10.
Synlett 2006, No. 19, 3231–3236 © Thieme Stuttgart · New York

LETTER
Conjugated Trinuclear Phthalocyanines Linked by Ethynyl Bridges
3235
All products gave satisfactory spectroscopic and analytical data (1H
NMR, IR, MALDI–TOF MS, UV–Vis). Compounds 1,6 2,6 3,15 7,13
and 96 were prepared according to published procedures.
1H NMR (300 MHz, CDCl3): d = 1.1 (m, 18 H, CH3), 1.7 (m, 12 H,
CH2CH3), 2.1 (m, 12 H, OCH2CH2), 4.5 (m, 12 H, OCH2), 7.5–9.0
(m, 24 H, ArH).
MS (MALDI–TOF, dithranol): m/z = 1269–1276 [M – I]+ (isotopic
pattern).
Synthesis of Iodohexabutoxyphthalocyaninatozinc(II) (4;
Equation 1)
A mixture of 4,5-dibutoxyphthalonitrile16 (150 mg, 0.551 mmol), 4-
iodophthalonitrile17 (47 mg, 0.184 mmol) and Zn(OAc)2×2H2O (88
mg, 0.399 mmol) in dimethylaminoethanol (2 mL) was heated at
140 °C for 16 h under an argon atmosphere. Then, the mixture was
cooled to r.t. and washed by centrifugation (H2O–MeOH, 3:1; 3000
rpm, 5 min) until the mother-liquor was colorless. The residue was
purified twice by column chromatography (SiO2, eluting with hex-
ane–1,4-dioxane, 4:1) affording compound 4 as a dark green solid
(39 mg, 19% yield); mp >300 °C; Rf (hexane–1,4-dioxane, 2:1)
0.61.
HRMS: m/z calcd for C74H78IN8O6PZn: 1396.41182; found:
1396.41197.
UV–Vis (CHCl3): lmax (log e, M–1 cm–1) = 713 (4.70), 667 (4.40),
644 (4.28), 607 (3.86), 373 (4.38) nm.
Synthesis of 4,5-[Hexabutoxyethynylphthalocyaninato-
zinc(II)]phthalonitrile (8; Equation 3); Typical Procedure
To a solution of 4,5-diethynylphthalonitrile (7;13 2.5 mg, 0.014
mmol) in degassed Et3N (3 mL) were added Pd(PPh3)2Cl2 (0.63 mg,
0.0009 mmol), CuI (0.2 mg, 0.0008 mmol) and iodo-Pc 4 (66 mg,
0.058 mmol). The reaction mixture was heated at 80 °C for 48 h un-
der N2. The solvent was evaporated under reduced pressure and the
crude product was purified by column chromatography twice (SiO2,
eluting with hexane–1,4-dioxane, 3:1) affording compound 8 as a
green solid (8.3 mg, 27% yield); mp >300 °C; Rf (hexane–1,4-diox-
ane, 2:1) 0.49.
IR (KBr): 3423, 2854, 1260, 1095 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.1–1.3 (m, 18 H, CH3), 1.3–1.6
(m, 12 H, CH2CH3), 1.7–1.9 (m, 12 H, OCH2CH2), 3.6–3.9 (m, 12
H, OCH2), 7.0–8.0 (m, 9 H, ArH).
MS (MALDI–TOF, dithranol): m/z = 1135–1141 [M + H]+ (isotopic
pattern).
IR (KBr): 3380, 2832, 2239, 2210, 1260, 1094 cm–1.
HRMS: m/z calcd for C56H63IN8O6Zn: 1134.32068; found:
1134.32097.
UV–Vis (CHCl3): lmax (log e, M–1 cm–1) = 681 (5.18), 612 (4.44),
356 (4.90) nm.
1H NMR (300 MHz, CDCl3): d = 1.1–1.4 (m, 36 H, CH2CH3), 1.5–
1.8 (m, 24 H, CH2CH3), 1.8–2.1 (m, 24 H, OCH2CH2), 3.8–4.1 (m,
24 H, OCH2), 7.3–9.0 (m, 20 H, ArH).
MS (MALDI–TOF, dithranol): m/z = 2202–2212 [M + H]+ (isotopic
pattern).
Synthesis of Symmetrical Pc-Based Triad 5, via Sonogashira
Cross-Coupling Reaction (Table 1, entry 1); Typical Procedure
A solution of diiodophthalocyanine 1 (15 mg, 0.012 mmol), ethy-
nylphthalocyanine 2 (38 mg, 0.037 mmol), Pd(PPh3)2Cl2 (5.3 mg,
0.0076 mmol), CuI (1.4 mg, 0.0076 mmol) and KI (39 mg, 0.238
mmol) in an anhyd and degassed Et3N–DMF (1:5, 4 mL) mixture
was heated at 80 °C under an argon atmosphere for 48 h. After re-
moval of the solvents under reduced pressure, column chromatog-
raphy (Bio-Beads, eluting with THF) of the crude product afforded
triad 5 as a green solid (14 mg, 39% yield); mp >300 °C; Rf (hex-
ane–1,4-dioxane, 2:1) 0.83.
HRMS: m/z calcd for C124H128N18O12Zn2: 2192.85420; found:
2192.85469.
UV–Vis (CHCl3): lmax (log e, M–1 cm–1) = 683 (5.16), 613 (4.28),
358 (4.88) nm.
Synthesis of Unsymmetrical Pc-Based Triad 10 (Equation 4);
Typical Procedure
A mixture of 4,5-di[ethynylzinc(II)Pc]phthalonitrile 8 (7.8 mg,
0.004 mmol) and 4,5-bis(propylsulfonyl)phthalonitrile (9; 4.1 mg,
0.012 mmol) was refluxed in dimethylaminoethanol (2 mL) under
argon for 24 h in the presence of CoCl2×6H2O (2 mg, 0.008 mmol).
The dark green mixture was cooled to r.t. and then the solvent was
removed under reduced pressure. Finally, the green precipitate was
chromatographed several times (Bio-Beads, eluting with THF by
column and then by preparative TLC) affording triad 10 as a green
solid (1.5 mg, 11% yield); mp >300 °C; Rf (hexane–1,4-dioxane,
2:1) 0.72.
IR (KBr): 3421, 2851, 2359, 1261, 1095 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.1–1.3 (m, 54 H, CH2CH3), 1.3–
1.6 (m, 36 H, CH2CH3), 1.7–1.9 (m, 36 H, OCH2CH2), 3.5–3.8 (m,
36 H, OCH2), 7.0–8.0 (m, 26 H, ArH).
MS (MALDI–TOF, dithranol): m/z = 3068–3081 [M + H]+ (isotopic
pattern).
HRMS: m/z calcd for C172H188N24O18Zn3: 3075.24078; found:
IR (KBr): 3470, 3420, 2970, 2851, 2359, 1294, 1260, 1096 cm–1.
3075.24093.
1H NMR (300 MHz, CDCl3): d = 1.0–1.3 (m, 54 H, CH2CH3), 1.4–
1.8 (m, 36 H, CH2CH3), 1.7–2.0 (m, 24 H, OCH2CH2), 3.0–3.2 (m,
12 H, SO2CH2), 3.7–4.1 (m, 24 H, OCH2), 7.2–8.9 (m, 26 H, ArH).
UV–Vis (CHCl3): lmax (log e, M–1 cm–1) = 681 (5.18), 612 (4.44),
356 (4.90) nm.
MS (MALDI–TOF, dithranol): m/z = 3269–3081 (isotopic pattern)
Synthesis of Phosphonium Salt 6 (Equation 2); Typical Proce-
dure
[M + H]+.
HRMS: m/z calcd for C166H176CoN24O24S6Zn2: 3270.95285; found:
3270.95298.
UV–Vis (CHCl3): lmax (log e, M–1 cm–1) = 695 (5.01), 673 (4.84),
622 (sh), 331 (4.90) nm.
A mixture of iodophthalocyanine 4 (15 mg, 0.013 mmol) and
Pd(PPh3)2Cl2 (12 mg, 0.017 mmol) in anhyd and degassed DMF (3
mL) was heated at 100 °C and stirred for 24 h, after which time the
solvent was removed under reduced pressure and the solid residue
was purified by column chromatography (SiO2, eluting with hex-
ane–THF, 2:1) affording compound 6 as a green solid (7.0 mg, 39%
yield); mp >300 °C; Rf (THF–hexane, 1:2) 0.52 (tailing).
Acknowledgment
IR (KBr): 3440, 2871, 1279, 1083 cm–1.
Funding from MEC (Spain-CTQ2005-08933/BQU) and Comuni-
dad de Madrid (Spain S-0505/PPQ/000225) is acknowledged.
D.D.D. thanks MEC (Spain) for a RyC contract.
Synlett 2006, No. 19, 3231–3236 © Thieme Stuttgart · New York

3236
E. M. García-Frutos et al.
LETTER
(5) Maya, E. M.; Vázquez, P.; Torres, T. Chem. Commun. 1997,
1175.
References
(1) (a) Yang, S. I.; Li, J.; Cho, H. S.; Kim, D.; Bocian, D. F.;
Holten, D.; Lindsey, J. S. J. Mater. Chem. 2000, 10, 283.
(b) Miller, M. A.; Lammi, R. K.; Prathapan, S.; Holten, D.;
Lindsey, J. S. J. Org. Chem. 2000, 65, 6634. (c) Yeow, E.
K. L.; Ghiggino, K. P.; Reek, J. N. H.; Crossley, M. J.;
Bosman, A. W.; Schenning, A. P. H. J.; Meijer, E. W. J.
Phys. Chem. B 2000, 104, 2596. (d) Guldi, D. M.;
Gouloumis, A.; Vázquez, P.; Torres, T.; Georgakilas, V.;
Prato, M. J. Am. Chem. Soc. 2005, 127, 5811. (e) de la
Escosura, A.; Martínez-Díaz, M. V.; Guldi, D. M.; Torres, T.
J. Am. Chem. Soc. 2006, 128, 4112. (f) González-
Rodríguez, D.; Torres, T.; Olmstead, M. M.; Rivera, J.;
Herranz, M. A.; Echegoyen, L.; Atienza-Castellanos, C.;
Guldi, D. M. J. Am. Chem. Soc. 2006, 128, 10680.
(2) (a) Li, D.; Ratner, M. A.; Marks, T. J. J. Am. Chem. Soc.
1988, 110, 1707. (b) de la Torre, G.; Vázquez, P.; Agulló-
López, F.; Torres, T. J. Mater. Chem. 1998, 8, 1671. (c) de
la Torre, G.; Vázquez, P.; Agulló-López, F.; Torres, T.
Chem. Rev. 2004, 104, 3723. (d) O’Flaherty, S. M.; Hold, S.
V.; Cook, M. J.; Torres, T.; Chen, Y.; Hanack, M.; Blau, W.
J. Adv. Mater. 2003, 15, 19.
(6) Maya, E. M.; Vázquez, P.; Torres, T.; Gobbi, L.; Diederich,
F.; Pyo, S.; Echegoyen, L. J. Org. Chem. 2000, 65, 823.
(7) (a) Maya, E. M.; García, C.; García-Frutos, E. M.; Vázquez,
P.; Torres, T. J. Org. Chem. 2000, 65, 2733. (b) Maya, E.
M.; García-Frutos, E. M.; Vázquez, P.; Torres, T.; Martín,
G.; Rojo, G.; Agulló-López, F.; González-Jonte, R. H.;
Ferro, V. R.; García de la Vega, J. M.; Ledoux, I.; Zyss, J. J.
Phys. Chem. A 2003, 107, 2110.
(8) González-Cabello, A.; Vázquez, P.; Torres, T.; Guldi, D. M.
J. Org. Chem. 2003, 68, 8635.
(9) For a recent review on the synthesis of alkynyl-substituted
Pcs, see: Bottari, G.; Díaz, D. D.; Torres, T. J. Porphyrins
Phthalocyanines 2006, in press.
(10) de la Torre, G.; Gouloumis, A.; Vázquez, P.; Torres, T.
Angew. Chem. Int. Ed. 2001, 40, 2895.
(11) Kalkan, A.; Koca, A.; Bayir, Z. A. Polyhedron 2004, 23,
3155.
(12) Poon, K. W.; Liu, W.; Chan, P. K.; Yang, Q.; Chan, T. W.
D.; Mak, T. C. W.; Ng, D. K. P. J. Org. Chem. 2001, 66,
1553.
(13) Leznoff, C. C.; Li, Z.; Isago, H.; D’Ascanio, A. M.;
Terekhov, D. S. J. Porphyrins Phthalocyanines 1999, 3, 406.
(14) (a) Blum, J.; Baidossi, W.; Badrieh, Y.; Hoffmann, R. E.;
Schumann, H. J. Org. Chem. 1995, 60, 4738. (b) Schreiner,
P. R.; Prall, M.; Lutz, V. Angew. Chem. Int. Ed. 2003, 42,
5757. (c) Kovalenko, S. V.; Peabody, S.; Manoharan, M.;
Clark, R. J.; Alabugin, I. V. Org. Lett. 2004, 6, 2457.
(15) García-Frutos, E. M.; Fernández-Lázaro, F.; Maya, E. M.;
Vázquez, P.; Torres, T. J. Org. Chem. 2000, 65, 6841.
(16) Berera, R.; Herrer, C.; van Stokkum, I. H. M.; Vengris, M.;
Kodis, G.; Palacios, R. E.; van Amerongen, H.; van
Grondelle, R.; Gust, D.; Moore, T. A.; Moore, A. L.; Kennis,
J. T. M. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 5343.
(17) Marcuccio, S. M.; Svirskaya, P. I.; Greenberg, S.; Lever, A.
B. P.; Leznoff, C. C.; Tomer, K. B. Can. J. Chem. 1985, 63,
3057.
(3) (a) Sastre, A.; del Rey, B.; Torres, T. J. Org. Chem. 1996, 61,
8591. (b) Sastre, A.; Díaz-García, M. A.; del Rey, B.;
Dhenaut, C.; Zyss, J.; Ledoux, I.; Agulló-López, F.; Torres,
T. J. Phys. Chem. A 1997, 101, 9773. (c) Tian, M.; Wada,
T.; Kimura-Suda, H.; Sasabe, H. J. Mater. Chem. 1997, 7,
861. (d) Sastre, A.; Torres, T.; Hanack, M. Tetrahedron Lett.
1995, 36, 8501. (e) Cabezón, B.; Rodríguez-Morgade, S.;
Torres, T. J. Org. Chem. 1995, 60, 1872. (f) de la Torre, G.;
Martínez-Díaz, M. V.; Ashton, P. R.; Torres, T. J. Org.
Chem. 1998, 63, 8888. (g) Calvete, M. J. F.; Dini, D.; Flom,
S. R.; Hanack, M.; Pong, R. G. S.; Shirk, J. S. Eur. J. Org.
Chem. 2005, 3499.
(4) (a) Rojo, G.; de la Torre, G.; García-Ruiz, J.; Ledoux, I.;
Torres, T.; Zyss, J.; Agulló-López, F. Chem. Phys. 1999,
245, 27. (b) Maya, E. M.; Vázquez, P.; Torres, T. Chem.
Eur. J. 1999, 5, 2004.
Synlett 2006, No. 19, 3231–3236 © Thieme Stuttgart · New York