Modular Synthesis of Benzene-Centered Porphyrin Trimers and a Dendritic Porphyrin Hexamer

Article abstract of DOI:10.1021/jo980846+

Rigid, star-shaped D₃-symmetric arrays have been synthesized in which three porphyrin macrocyeles are attached to the 1,3, and 5 positions each of a benzene core through linkers consisting of collinear repetitive phenylethynyl units. Using the

Full text of DOI:10.1021/jo980846+

5568
J . Org. Chem. 1998, 63, 5568-5580
Mod u la r Syn th esis of Ben zen e-Cen ter ed P or p h yr in Tr im er s a n d a
Den d r itic P or p h yr in Hexa m er †
Olivier Mongin, Cyril Papamicae¨l, Nicolas Hoyler, and Albert Gossauer*
Institut fu¨r Organische Chemie der Universita¨t, Universita¨t Freiburg Schweiz, Ch. du Muse´e 9,
CH-1700 Fribourg, Switzerland
Received May 12, 1998
Rigid, star-shaped D3-symmetric arrays have been synthesized in which three porphyrin macrocycles
are attached to the 1, 3, and 5 positions each of a benzene core through linkers consisting of collinear
repetitive phenylethynyl units. Using the same methodology, a dendridic porphyrin hexamer having
an external diameter of ca. 10 nm has been also obtained. By successive substitution of the three
benzene positions, both a porphyrin trimer, the three linkers of which are of different length, and
a starlike porphyrin, in which the complexed metal ions are different from each other, have been
synthesized. The latter is the first example of a prochiral arrangement of metal ions in a D3-
symmetric ligand. To investigate their capability of forming ordered self-assembled monolayers
on gold substrates, some of the porphyrin trimers and the dendritic porphyrin hexamer described
in this work bear meta-thioanisole units at the apical positions. Analogously to similar multipor-
phyrin systems described in the literature, in which, however, the chromophores were arranged
collinearly, the interaction between the chromophores of the multiporphyrin arrays described in
this work is negligible, in the ground state, while effective energy transfer takes place in the singlet
excited state.
In tr od u ction
hensive review article20 as well as by Mu¨llen’s work on
polyphenylene dendrimers.21,22 As a matter of fact, the
use of dendrimers in molecular recognition and self-
assembling systems is attracting increasing attention in
supramolecular chemistry.23 Moreover, metal-donor
atom interactions in dendrimers containing complexed
metal ions increase still more the possibilities for their
practical applications in diverse areas including material
science and mimicking of the essential features used by
living systems in energy-transfer processes.24
With this in mind, the syntheses of a series of benzene-
centered porphyrin trimers as well as of a dendritic
porphyrin hexamer, all of them possessing D3h symmetry,
have been carried out in the present work by means of
the building block approach developped by Lindsey et
al.25 for covalent assembly of multiporphyrin arrays and
Owing to their ready accessibility,1 large molecular
size,2 and rigid planar geometry as well as their electronic
properties and their ability to complex almost any kind
of metal ions, porphyrins are irreplaceable building
blocks for the syntheses of both straight-chain and
branched extended molecular systems designed to per-
form a great diversity of functions as, for instance,
enzyme-mimetic catalysts,3-5 optical switches,6 molecular
photonic wires,7-10 molecular optoelectronic gates,11 and
light harvesting arrays.12-19 On the other hand, the
prospective application potential of branched, monodis-
perse, sequence-specific oligomers of polycyclic aromatic
macromolecular systems for the construction of nano-
structures has been emphasized recently in a compre-
* To whom correspondence should be addressed. Phone: 41-26-300
8770. Fax: 41-26-300 9739. E-mail: albert.gossauer@unifr.ch.
† Dedicated to Prof. A. Ian Scott of the Texas A & M University on
the occasion of his 70th birthday.
(13) Prathapan, S.; J ohnson, T. E.; Lindsey, J . S. J . Am. Chem. Soc.
1993, 115, 7519-7520.
(14) Seth, J .; Palaniappan, V.; J ohnson, T. E.; Prathapan, S.;
Lindsey, J . S.; Bocian, D. F. J . Am. Chem. Soc. 1994, 116, 10578-
10592.
(1) Dolphin, D., Ed. The Porphyrins; Academic Press: New York,
1979; Vol. 1, Chapters 3-6.
(15) Wagner, R. W.; J ohnson, T. E.; Li, F.; Lindsey, J . S. J . Org.
Chem. 1995, 60, 5266-5273.
(16) Wagner, R. W.; J ohnson, T. E.; Lindsey, J . S. J . Am. Chem.
Soc. 1996, 118, 11166-11180.
(2) Webb, L. E.; Fleischer, E. B. J . Am. Chem. Soc. 1965, 87, 667-
669.
(3) Milgrom, L. R. J . Chem. Soc., Perkin Trans. 1 1983, 2535-2539.
(4) Davila, J .; Harriman, A.; Milgrom, L. R. Chem. Phys. Lett. 1987,
136, 427-430.
(17) Hsiao, J .-S.; Krueger, B. P.; Wagner, R. W.; J ohnson, T. E.;
Delaney, J . K.; Mauzerall, D. C.; Fleming, G. R.; Lindsey, J . S.; Bocian,
D. F.; Donohoe, R. J . J . Am. Chem. Soc. 1996, 118, 11181-11193.
(18) Seth, J .; Palaniappan, V.; Wagner, R. W.; J ohnson, T. E.;
Lindsey, J . S.; Bocian, D. F. J . Am. Chem. Soc. 1996, 118, 11194-
11207.
(19) Gauler, R.; Risch, N. Tetrahedron Lett. 1997, 38, 223-224.
(20) Young, J . K.; Moore, J . S. In Modern Acetylen Chemistry; Stang,
P. J ., Diederich, F., Eds.; VCH: Weinheim, 1995; pp 415-442.
(21) Morgenroth, F.; Reuther, E.; Mu¨llen, K. Angew. Chem. 1997,
109, 647-649; Angew. Chem., Int. Ed. Engl. 1997, 36, 631-634 and
references therein.
(22) Iyer, V. S.; Wehmeier, M.; Brand, J . D.; Keegstra, M. A.; Mu¨llen,
K. Angew. Chem. 1997, 109, 1676-1679; Angew. Chem., Int. Ed. Engl.
1997, 36, 1604-1607.
(23) Zeng, F.; Zimmerman, S. C. Chem. Rev. 1997, 97, 1681-1712.
(24) Constable, E. C. J . Chem. Soc., Chem. Commun. 1997, 1073-
1080.
(5) Bonnett, R.; Ioannou, S.; Pearson, C.; Petty, M. C.; Roger-Evans,
M.; Wilkins, R. F. J . Mater. Chem. 1995, 5, 237-242.
(6) O’Neil, M. P.; Niemczyk, M. P.; Svec, W. A.; Gosztola, D.; Gaines,
G. L., III; Wasielewski, M. R. Science 1992, 257, 63-65.
(7) Crossley, M. J .; Burn, P. L. J . Chem. Soc., Chem. Commun. 1991,
1569-1571.
(8) Wagner, R. W.; Lindsey, J . S. J . Am. Chem. Soc. 1994, 116,
9759-9760.
(9) Sessler, J . L.; Capuano, V. L.; Harriman, A. J . Am. Chem. Soc.
1993, 115, 4618-4628.
(10) Ono, N.; Tomita, H.; Maruyama, K. J . Chem. Soc., Perkin Trans.
1 1992, 2453-2456.
(11) Wagner, R. W.; Lindsey, J . S.; Seth, J .; Palaniappan, V.; Bocian,
D. F. J . Am. Chem. Soc. 1996, 118, 3996-3997.
(12) Wennerstro¨m, O.; Ericsson, H.; Raston, I.; Svensson, S.; Pimlott,
W. Tetrahedron Lett. 1989, 30, 1129-1132.
S0022-3263(98)00846-9 CCC: $15.00 © 1998 American Chemical Society
Published on Web 07/10/1998

Synthesis of Benzene-Centered Porphyrin Trimers
J . Org. Chem., Vol. 63, No. 16, 1998 5569
Sch em e 1a
Sch em e 2a
a
Key: (a) (4-iodophenyl)ethynyltrimethylsilane, Pd(PPh3)4, CuI,
toluene/Et3N, 35 °C, 12 h (81%); (b) CH3I, 130 °C, 12 h (90%); (c)
HCtCSi-i-Pr3, Pd(PPh3)2Cl2, CuI, Et3N, 45 °C, 12 h (99%); (d) 1
N NaOH, THF (86%).
a
Key: (a) HCtCSiMe3 (1 equiv), Pd(PPh3)4, CuI, pyridine/Et3N,
Sch em e 3a
35 °C, 2 h (51%); (b) 2-methyl-3-butyn-2-ol, same catalyst and
solvent as in a, 40 °C, 4 h (65%); (c) HCtCSiMe3 (excess),
Pd(PPh3)Cl2, CuI, Et3N, 20 °C, 3 h (99%); (d) 1 N NaOH, THF
(87%); (e) 5b, Pd(PPh3)4, CuI, toluene/Et3N, 45 °C, 12 h (70%); (f)
TBAF, THF (69%).
a
Key: (a) tert-BuLi, Et2O, -75 °C; I2, -75 °C f -20 °C (91%);
adapted in our laboratory for the synthesis of “tripoda-
phyrins”.26,27 The porphyrin oligomers described in this
work belong to a class of porphine derivatives designated
as stellular (star-shaped) porphyrins.5 In contrast to a
likewise benzene-centered but C3h-symmetric porphyrin
trimer, the synthesis of which has been reported re-
cently,19 compounds 10, 11, 14, 17, and 19 are less
conformatively flexible, thus enabling a better through-
bond electronic interaction between the attached por-
phyrin macrocycles (cf. ref 14). Some examples of rigid,
porphine-centered, starlike porphyrin arrays possessing
D4h symmetry have been reported earlier by Wenner-
stro¨m et al.12 and Lindsey et al.13 as well.
(b) HCtCSi-i-Pr3, Pd(PPh3)2Cl2, CuI, toluene/Et3N, 20 °C, 2 h
(98%); (c) TBAF, THF (99%).
replacement of the iodine atoms of 1a by ethynyl groups
is possible, thus yielding the corresponding monoethynyl
and diethynyl derivatives (2 and 3, respectively). In the
latter, two different protecting groups of the terminal
ethyne-C-atoms were used to enable the stepwise syn-
thesis of star-shaped porphyrins with different apical
macrocycles (17a -c). Likewise, 2 was used as a building
block for the synthesis of the dendritic porphyrin hex-
amer 19. Finally, reaction of 2 with 4-[(triisopropylsilyl)-
ethynyl]-4′-ethynyltolane (5d ), which was prepared from
5b via 4-[(trimethylsilyl)ethynyl]-4′-[(triisopropylsilyl)-
ethynyl]tolane (5c) by selective cleavage of the trimeth-
ylsilyl protecting group of the latter (Scheme 2), yielded
the suitable linker 12 for the synthesis of a star-shaped
porphyrin trimer 14, in which the three linkers are of
different length.
Syn th esis of m eso-Tetr a a r ylp or p h yr in Bu ild in g
Block s. The synthesis of the metal chelates 9b,c of 5-(4-
iodophenyl)-10,15,20-triphenylporphine 9a has been pre-
viously described.26,27 As the solubility in organic sol-
vents of multiporphyrin arrays synthesized therefrom
attained a practical limit with compound 10e (∼10-4
mol/L in CHCl3), the porphyrin derivative 7 (Scheme 4)
was used as precursor of a new series of multiporphyrin
arrays, including the dendritic porphyrin hexamer 19,
in which the ortho substituents at the phenyl rings
prevent cofacial aggregation of the macrocycles, thus
improving their solubility (cf. ref 16). Moreover, elonga-
tion of one of the p-iodophenyl substituents of 7 with a
meta-ethynylthioanisole unit (cf. Scheme 3) yielded a
meso-tetraarylporphine intermediate 8a , which not only
led to more soluble final products but also endowed them
with functional groups, which interact strongly with gold
covered substrates, so that highly ordered self-assembled
monolayers (SAM) may be formed on such substrates by
spontaneous adsorption from solution (cf. ref 34). Sub-
stitution of the iodine atoms of 8a and 9c by ethynyl
Resu lts
Syn th esis of P oly(p h en yla cetylen e) Lin k er s. The
core of all multiporphyrin arrays described in this work
has been constructed using 1,3,5-triiodobenzene (1a )28 as
starting material (Scheme 1). Its reaction with (trimeth-
ylsilyl)acetylene using palladium(II) as a catalyst29 af-
fords, after cleavage of the trimethylsilyl protecting
groups, 1,3,5-triethynylbenzene (1c),30 which was used
for the synthesis of the porphyrin trimers 10b-d and
11a ,b. On the other hand, 1e, as the larger core of the
porphyrin trimers 10e and 11c, was obtained by pal-
ladium(0)-catalyzed reaction31 of 1c with 4-iodo-4′-[(tri-
methylsilyl)ethynyl]tolane (5b),32 which was prepared in
a two-step sequence from 3,3-diethyl-1-(4-ethynylphenyl)-
1-triazene (4)33 (Scheme 2). Alternatively, successive
(25) Lindsey, J . S.; Prathapan, S.; J ohnson, T. E.; Wagner, R. W.
Tetrahedron 1994, 50, 8941-8968.
(26) Mongin, O.; Gossauer, A. Tetrahedron Lett. 1996, 37, 3825-
3828.
(27) Mongin, O.; Gossauer, A. Tetrahedron 1997, 53, 6835-6846.
(28) (a) Willgerodt, C.; Arnold, E. Chem. Ber. 1901, 34, 3343-3354.
(b) Ozasa, S.; Fujioka, Y.; Hashino, H.; Kimura, N.; Ibuki, E. Chem.
Pharm. Bull. 1983, 31, 2313-2320.
(29) Takahashi, S.; Kuroyama, Y.; Sonogashira, K.; Hagihara, N.
Synthesis 1980, 627-630.
(30) (a) Hu¨bel, W.; Mere´nyi, R. Angew. Chem. 1962, 74, 781. Angew.
Chem., Int. Ed. Engl. 1963, 2, 42. (b) Weber, E.; Hecker, M.; Koepp,
E.; Orlia, W.; Czugler, M.; Cso¨regh, I. J . Chem. Soc., Perkin Trans. 1
1988, 1251-1257.
(31) For the synthesis of 1d , Pd(PPh3)4 proved to be superior to
Pd(PPh3)2Cl2, as a catalyst, to avoid the formation of dimers of 1c, as
byproducts (cf.: Villemin, D.; Schigeko, E. J . Organomet. Chem. 1985,
293, C10-C12.
(32) Hsung, R. P.; Chidsey, C. E. D.; Sita, L. R. Organometallics
1995, 14, 4808-4815.
(33) Moore, J . S.; Weinstein, E. J .; Wu, Z. Tetrahedron Lett. 1991,
32, 2465-2466.
(34) (a) Ulman, A. An Introduction to Ultrathin Organic Films:
From Langmuir-Blodgett Films to Self-Assembly; Academic Press:
Boston, 1991. (b) Dubois, L. H.; Nuzzo, R. G. Annu. Rev. Phys. Chem.
1992, 43, 437-463.

5570 J . Org. Chem., Vol. 63, No. 16, 1998
Mongin et al.
Sch em e 4a
a
Key: (a) 6c, Pd2dba3, AsPh3, DMF/Et3N, 45 °C, 3 h (41%); (b) HCtCSiMe3, same conditions as in a (79%); (c) 1 N NaOH, THF (87%);
(d) 4,4′-diiodotolane, Pd(PPh3)4, DMF/Et3N, 45 °C, 18 h (89%); (e) TBAF, THF (53%).
F igu r e 1. Absorption spectra of 17a -c (solid lines). Composite spectra in the range of absorption of the porphyrin chromophores
were generated by adding the spectra of the individual TPP chromophores (dotted lines). Spectra were measured in benzene at
room temperature.
groups was achieved by reaction with (trimethylsilyl)-
acetylene and subsequent cleavage of the terminal tri-
methylsilyl group (cf. ref 27). Elongation of the ethyn-
ylphenyl group through reaction with 4,4′-diiodotolane
led finally to the corresponding intermediates 8d and
9d ,27 respectively (Schemes 4 and 5, respectively). De-
rivative 8f was directly obtained from 8a by reaction with
5d and following deprotection of the terminal ethyne
group.
Syn th esis of Mu ltip or p h yr in Ar r a ys. Reaction of
1,3,5-triethynylbenzene (1c) with 9c and 9d in the
presence of Pd(PPh3)4 led to D3-symmetric porphyrin
trimers 10c and 10d , respectively (Scheme 5). The latter
was also obtained by reacting the larger D3-symmetric
core 1e with the tetraphenylporphyrin derivative 9c. The
yield of this reaction was perceptibly improved from 18%
up to 61%, however, using triphenylarsine instead of
triphenylphosphine as the ligand of the palladium cata-
lyst (cf. ref 35). The same procedure was used for the
synthesis of the largest compound in this series (i.e., 10e),
which was obtained by reaction 9d with 1e. Analogously,
the more soluble porphyrin trimers 11a -c were prepared
using 8a and 8d instead of 9c and 9d , respectively, as
the building blocks. The alternative synthetic approach,
in which the reactive ethynyl groups are located on the
porphyrin moieties and the iodine atoms in the core was
discarded because it led to the formation of butadiyne-
linked porphyrin dimers as byproducts, which were very
difficult to separate from the desired D3-symmetric
trimers.
The porphyrin trimer with three linkers of different
lengths (14) was synthesized from the iodobenzene
derivative 12 by successive reaction with 8c and, after
cleavage of both trialkylsilyl protecting groups, with an
excess (2.5 mol) of the iodophenylporphyrin derivative
8d (Scheme 6). On the other hand, selective cleavage of
the trimethylsilyl and 2-hydroxylpropyl protecting group
of 15a , which was prepared from 3 (cf. Experimental
Section), followed by reaction with the nickel and copper
chelates of 9a , respectively, led to a porphyrin trimer
(17b), in which the complexed metal ions are different
from each other. By the same strategy, other combina-
tions of porphyrin metal chelates and metal-free porphy-
(35) Farina, V.; Krishnan, B. J . Am. Chem. Soc. 1991, 113, 9585-
9595.

Synthesis of Benzene-Centered Porphyrin Trimers
J . Org. Chem., Vol. 63, No. 16, 1998 5571

5572 J . Org. Chem., Vol. 63, No. 16, 1998
Mongin et al.
Sch em e 6a
a
Key: (a) 5d , Pd(PPh3)4, CuI, pyridine/Et3N, 35 °C, 2 h (61%); (b) 8c, Pd(PPh3)4, DMF/Et3N, 45 °C, 20 h (81%); (c) TBAF, THF (95%);
(d) 8d , same conditions as in b (67%).
rin ligands could be obtained (Scheme 7). Finally,
reaction of diiodobenzene derivative 2 with 3 equivalents
of 8c led to a porphyrin dimer 18a , which after cleavage
of the trimethylsilyl protecting group, was reacted with
an excess of 4,4′-diiodotolane to give the bifurcated
porphyrin dimer 18c. The latter was reacted with 1,3,5-
triethynylbenzene (1c) in the presence of tris(diben-
zylideneacetone)dipalladium (Pd2dba3) and triphenyl-
arsine to yield the dendritic porphyrin hexamer 19
possessing an external diameter of ca. 10 nm (Scheme
8).
compound 14, the absorption maxima of which cor-
respond to those of its isomer 11b although the distance
between the chromophores is different in both arrays
(Figure 2). Actually, a lack of interaction between the
individual chromophores of the arrays described in this
work is not surprising, since their linkers are attached
to the meta positions of the benzene core (cf. ref 36). In
contrast, λmax in the range of absorption of the linkers
theirselves shifts to longer wavelengths on increasing the
number of p-phenylene ethynylene units (Figure 2). On
the other hand, efficient singlet excited-state energy
transfer is observed between the chromophores in the
heteroorganometallic derivatives 17a -c with concomi-
tant diminution of emitted light (cf. Table 1). Particu-
larly interesting in this connection is compound 17a , in
which the emission of the Zn-tetraphenylporphine (Zn-
TPP) chromophore is almost completely quenched, while
74% of the emission of the tetraphenylporphine (TPP)
chromophore is still present (Figure 3). Efficient transfer
of singlet excited-state energy from the Zn porphyrin to
the free-base porphyrin chromophore has been observed
previously both through-bond via the linkers (Dexter-type
mechanism)17,37,38 and by the Fo¨rster mechanism39 in
dimeric and trimeric porphyrin arrays, in which Zn TPP
and free-base TPP chromophores are arranged col-
linearly. Whether in the case of 17a the loss of excitation
Discu ssion
Although the primary goal of the present work is the
synthesis of nanometer-sized multiporphyrin arrays,
which may be visualized by commercially available
scanning probe microscopes (cf. refs 26 and 27), rather
than the study of their photodynamic properties, some
features of the energy absorption and emission of the
corresponding chromophores deserve to be commented
here briefly. Thus, the ground-state absorption of the
multiporphyrin arrays is a sum of the absorption spectra
of the individual chromophores both in the range of
absorption of the porphyrin moieties (Figure 1) and the
p-phenylene ethynylene linkers (Figure 2), suggesting
that electronic coupling between the chromophores is
weak. This is particularly manifest in the case of
(36) Tabushi, I.; Sasaki, T. Tetrahedron Lett. 1982, 23, 1913-1916.

Synthesis of Benzene-Centered Porphyrin Trimers
J . Org. Chem., Vol. 63, No. 16, 1998 5573
Sch em e 7a
a
Key: (a) TBAF, THF (94%); (b) 9b, Pd(PPh3)4, DMF/Et3N, 45 °C, 20 h (86%); (c) KOH, i-PrOH/toluene, reflux, 2 h (89%); (d) 9a , same
conditions as in b (82% of 17a ); (e) copper chelate of 9a , same conditions as in b (62% of 17b); (f) (CH3CO2)2Cu‚H2O, CHCl3/MeOH, 20 °C,
15 min (94%); (g) TFA, CHCl3, 20 °C, 2 h (97%).
Ta ble 1. Qu a n tu m Yield s of F lu or escen cea
energy of the Zn TPP chromophore takes place by
quantum yields (Φf)
preferential transfer of the latter to the (nonfluorescent)
Ni TPP chromophore or through the free-base porphyrin
macrocycle is presently under investigation. Neverthe-
less, the photodynamic behavior of the multiporphyrin
arrays described in the present work contrasts with that
of similarly structured tripodaphyrins, in which no
singlet excited-state energy transfer between Zn TPP and
Ni TPP or Cu TPP chromophores could be observed.27
compd
free base porphb
Zn porphb
ZnTPP
TPP
0.03340
0.1141
0.095
10a
10c
10d
17a
17b
17c
0.039
0.040
0.004
0.0025
0.082
0.046
Exp er im en ta l Section
a
b
Emission spectra were measured from 570 to 800 nm. The
Gen er a l Meth od s. All air- or water-sensitive reactions
were carried out under argon. Solvents were generally dried
and distilled prior to use. Reactions were monitored by thin-
layer chromatography (TLC) on E. Merck silica gel 60F254 (0.2
mm) precoated aluminum foils. Column chromatography
quantum yields of emission were determined with λex 550 nm; the
emission intensity was integrated from λem 570 to 800 nm. The
integrated areas of the free base porphyrin (TPP) and of the Zn
TPP emission in heterometallic arrays were measured for the 690-
800 nm and 570-620 nm range, respectively, and have been
normalized to the emission of the corresponding monomers,
allowing for the absorbance ratios at λmax 550 nm of the different
chromophores present in the molecule. It was assumed that the
TPP and Zn TPP emissions have the same spectral profile in the
arrays as in the corresponding porphyrin monomers. Quantum
yields of TPP emission determined with λex 648 nm, where only
the free base porphyrin absorbs, gave the same results.
(37) Gust, D.; Moore, T. A.; Moore, A. L.; Gao, F.; Luttrull, D.;
DeGraziano, J . M.; Ma, X. C.; Makings, L. R.; Lee, S.-J .; Trier, T. T.;
Bittersmann, E.; Seely, G. R.; Woodward, S.; Bensasson, R. V.; Rouge´e,
M.; De Schryver, F. C.; Van der Auweraer, M. J . Am. Chem. Soc. 1991,
113, 3638-3649.
(38) Osuka, A.; Tanabe, N.; Kawabata, S.; Yamazaki, I.; Nishimura,
Y. J . Org. Chem. 1995, 60, 7177-7185.
(39) Brookfield, R. L.; Ellul, H.; Harriman, A.; Porter, G. J . Chem.
Soc., Faraday Trans. 2, 1986, 82, 219-233.
(CC): E. Merck silica gel 60 (230-400 mesh). UV/VIS λmax
(log ꢀ) and emission spectra (EMS) λem are reported in nm. 1H

5574 J . Org. Chem., Vol. 63, No. 16, 1998
Mongin et al.
mmol) were added. Thereafter, the mixture was stirred at 20
°C for 3 h. The solvent was removed under reduced pressure,
and the crude product was purified by CC (hexane) to yield
1
112 mg (99%) of 1b: mp 79-80 °C; H NMR (200.00 MHz) δ
0.23 (s, 27H), 7.49 (s, 3H). 13C NMR (50.30 MHz) δ -0.2, 95.6,
103.2, 123.6, 134.9; EI-MS 366 (M+, 30), 351 ([M - CH3]+, 100),
168 (40). Anal. Calcd for C21H30Si3 (366.73): C, 68.78; H, 8.25.
Found: C, 68.59; H, 8.43.
1,3,5-Tr ieth yn ylben zen e (1c). To a solution of 1b (456
mg, 1.24 mmol) in THF (5 mL) was added 3 mL of aqueous
NaOH (1 N), and the mixture was stirred vigorously at 20 °C
for 2 h. After evaporation of the THF, CH2Cl2 was added, and
the organic layer was separated. The aqueous layer was
extracted with CH2Cl2, and the combined organic phases were
dried (Na2SO4). The residue obtained after removal of the
solvent was purified by CC (hexane) to yield 163 mg (87%) of
1c: mp 104.5-105 °C (lit.30a mp 105-107 °C, lit.30b mp 102-
103 °C).
[1,3,5-Ben zen et r iylt r is(2,1-et h yn ed iyl-4,1-p h en ylen e-
2,1-eth yn ediyl-4,1-ph en ylen e-2,1-eth yn ediyl)]tr is(tr im eth -
ylsila n e) (1d ). Air was removed from a solution of 1c (4.83
mg, 32.1 µmol) and 5b (39.4 mg, 98.4 µmol) in 3 mL of toluene/
Et3N (5:1) by blowing argon for 30 min. Then, Pd(PPh3)4 (6.4
mg, 5.5 µmol) and CuI (2.0 mg, 10.5 µmol) were added, and
the mixture was heated at 45 °C for 12 h. The solvent was
removed under reduced pressure, and the crude product was
purified by CC (CH2Cl2/hexane: gradient from 1:9 to 1:4) to
yield 21.9 mg (70%) of 1d : mp 252 °C; 1H NMR (200.00 MHz)
F igu r e 2. Absorption spectrum of 14 (s). For comparison,
the absorption spectrum of the isomeric D3h symmetric trimer
11b is shown (-‚-). Inset: composite spectrum (‚‚‚) in the
range of absorption of the p-phenylene ethynylene linkers
generated by adding the absorption of each linker obtained
from the spectra of 11a (- - -), 11b (-‚-), 11c (- -). Spectra
were measured in benzene at room temperature.
δ 0.27 (s, 27H), 7.47 (m, 12H), 7.52 (m, 12H), 7.67 (s, 3H); 13
C
NMR (50.30 MHz) δ -0.1, 89.6, 90.3, 90.9, 91.1, 96.5, 104.5,
122.7, 123.0, 123.2, 123.9, 131.4, 131.7, 131.9, 134.2; FAB-MS
966 (M+). Anal. Calcd for C69H54Si3 (967.44): C, 85.66; H,
5.63. Found: C, 85.35; H, 5.94.
1,3,5-Tr is[[4-[(4-eth yn ylph en yl)eth yn yl]ph en yl]eth yn yl]-
ben zen e (1e). To a solution of 1d (44.9 mg, 46.4 µmol) in 6.3
mL of THF was added TBAF (1 M in THF, 0.14 mL, 0.14
mmol), and the mixture was stirred for 45 min at 20 °C. A
few grains of CaCl2 were added to remove any excess fluoride
(cf. ref 42) and the solvent was evaporated. The crude product
was purified by CC (CH2Cl2/hexane 1:4) to yield 24 mg (69%)
of 1e as a white solid: mp > 360 °C; 1H NMR (200.00 MHz) δ
3.19 (s, 3H), 7.49 (m, 12H), 7.53 (m, 12H), 7.67 (s, 3H); 13C
NMR (50.30 MHz) δ 79.09, 83.2, 89.6, 90.3, 90.9, 122.1, 122.8,
123.2, 123.4, 123.9, 131.5, 131.7, 132.1, 134.2; FAB-MS 750
(M+). Anal. Calcd for C60H30 (750.89): C, 95.97; H, 4.03.
Found: C, 95.57; H, 4.33.
[(3,5-Diiod op h en yl)eth yn yl]tr im eth ylsila n e (2). Air
was removed from a solution of 1a (205 mg, 0.45 mmol) in 16
mL of pyridine/Et3N (1:1) by blowing argon for 20 min. Then,
Pd(PPh3)4 (16 mg, 0.014 mmol), CuI (5.3 mg, 0.028 mmol), and
TMSA (62 µL, 0.45 mmol) were added, and the mixture was
stirred at 35 °C for 2 h. The solvent was evaporated under
reduced pressure, and then hexane was added to the residue.
The insoluble part was removed by filtration, the solvent was
evaporated, and the residue was purified by CC (hexane) to
yield 98 mg (51%) of 2 as a colorless oil: 1H NMR (200.00 MHz)
δ 0.23 (s, 9H), 7.76 (d, J ) 1.6, 2H), 7.99 (t, J ) 1.6, 1H); 13C
NMR (50.30 MHz) δ -0.3, 93.9, 97.5, 101.3, 126.7, 139.7, 145.1;
EI-MS 426 (M+, 24), 411 ([M - CH3]+, 63), 284 ([M - I]+, 9),
157 ([M - 2I]+, 100). Anal. Calcd for C11H12I2Si (426.11): C,
31.00; H, 2.84. Found: C, 30.70; H, 3.01.
4-[5-Iod o-3-[(tr im eth ylsilyl)eth yn yl]p h en yl]-2-m eth yl-
3-bu tyn -2-ol (3). Air was removed from a solution of 2 (50
mg, 0.117 mmol) in 6 mL of pyridine/Et3N (5:1) by blowing
argon for 20 min. Then, Pd(PPh3)4 (4.1 mg, 3.6 µmol), CuI
(1.4 mg, 7.4 µmol), and 2-methyl-3-butyn-2-ol (11.4 µL, 0.117
mmol) were added, and deaeration was continued for 10 min.
Thereafter, the mixture was heated at 40 °C for 4 h. The
F igu r e 3. Emission spectrum of 17a (s) in benzene at room
temperature (λex 550 nm). For comparison, the emission
spectra observed from equimolar solutions of the porphyrin
monomers Zn TPP (- - -) and TPP (‚‚‚) are shown.
and 13C NMR spectra were recorded in CDCl3. Chemical shifts
(δ) are given in ppm relative to Me4Si as internal standard, J
values in Hz. Tetrakis(triphenylphosphine)palladium, tris(di-
benzylideneacetone)dipalladium (Pd2dba3), triphenylarsine,
and tetrabutylammonium fluoride (TBAF) were purchased
from Aldrich Chemie (CH-9471 Buchs); 1-bromo-3-(methylth-
io)benzene from MTM Research Chemicals, Lancaster Syn-
thesis Division (F-67800 Bischheim); dimethylformamide (DMF),
trifluoroacetic acid (TFA), tetrahydrofuran (THF), (trimeth-
ylsilyl)acetylene (TMSA), 2-methyl-3-butyn-2-ol, and other
reagents from Fluka Chemie AG (CH-9471 Buchs).
(40) Quimby, D. J .; Longo, F. R. J . Am. Chem. Soc. 1975, 97, 5111-
5117.
(41) Seybold, P. G.; Gouterman, M. J . Mol. Spectrosc. 1969, 31,
1-13.
(42) Anderson, S.; Anderson, H. L.; Sanders, J . K. M. J . Chem. Soc.,
Perkin Trans. 1 1995, 2255-2267.
(1,3,5-Ben zen etr iyltr i-2,1-eth yn ed iyl)tr is(tr im eth ylsi-
la n e) (1b). Air was removed from
a solution of 1,3,5-
triodobenzene (1a )28 (140 mg, 0.307 mmol) in Et3N (12 mL)
by blowing argon for 30 min. Then, Pd(PPh3)2Cl2 (26 mg, 0.037
mmol), CuI (14 mg, 0.074 mmol), and TMSA (0.425 mL, 3.07

Synthesis of Benzene-Centered Porphyrin Trimers
J . Org. Chem., Vol. 63, No. 16, 1998 5575

5576 J . Org. Chem., Vol. 63, No. 16, 1998
Mongin et al.
solvent was removed under reduced pressure, and the crude
product was purified by CC (CH2Cl2/hexane: gradient from
1:9 to 7:3) to yield 29 mg (65%) of 3 as a colorless oil: 1H NMR
(200.00 MHz) δ 0.23 (s, 9H), 1.59 (s, 6H), 2.02 (br s, 1H), 7.47
NMR (200.00 MHz) δ 2.46 (s, 3H), 6.99 (t, J ) 7.8, 1H), 7.20
(ddd, J ) 7.8, 1.7, 1.7, 1H), 7.46 (ddd, J ) 7.8, 1.7, 1.7, 1H),
7.56 (t, J ) 1.7, 1H); 13C NMR (50.30 MHz) δ 15.7, 94.7, 125.7,
130.2, 134.0, 134.7, 141.0; EI-MS 250 (M+, 100), 123 ([M -
I]+, 50), 108 ([M - CH3 - I]+, 51). Anal. Calcd for C7H7IS
(250.10): C, 33.62; H, 2.82. Found: C, 33.75; H, 2.78.
Tr iisopr opyl[[3-(m eth ylth io)ph en yl]eth yn yl]silan e (6b).
Air was removed from a solution of 6a (125 mg, 0.5 mmol) in
8 mL of toluene/Et3N (5:1) by blowing argon for 30 min. Then,
Pd(PPh3)2Cl2 (17.5 mg, 0.025 mmol), CuI (9.5 mg, 0.05 mmol),
and ethynyltriisopropylsilane (0.33 mL, 1.5 mmol) were added.
Thereafter, the mixture was stirred at 20 °C for 2 h. The
solvent was removed under reduced pressure, and the residue
was purified by CC (CH2Cl2/hexane 1:19) to yield 149 mg (98%)
of 6b as a colorless oil: 1H NMR (200.00 MHz) δ 1.13 (m, 21H),
2.47 (s, 3H), 7.16-7.27 (m, 3H), 7.32-7.36 (m, 1H); 13C NMR
(50.30 MHz) δ 11.3, 15.8, 18.7, 91.0, 106.6, 124.2, 126.6, 128.5,
128.8, 129.8, 138.7; EI-MS 304 (M+, 34), 261 ([M - i-Pr]+, 100).
Anal. Calcd for C18H28SSi (304.57): C, 70.98; H, 9.27.
Found: C, 71.22; H, 9.39.
1-Eth yn yl-3-(m eth ylth io)ben zen e (6c) was obtained in
99% yield (71.4 mg) as a colorless oil, as described for 4, from
6b (148 mg, 0.49 mmol), after purification by CC (CH2Cl2/
hexane 1:19): 1H NMR (200.00 MHz) δ 2.47 (s, 3H), 3.08 (s,
1H), 7.20-7.27 (m, 3H), 7.34-7.37 (m, 1H); 13C NMR (50.30
MHz) δ 15.6, 77.5, 83.2, 122.7, 126.9, 128.6, 128.7, 129.5, 138.9;
EI-MS 148 (M+, 100). Anal. Calcd for C9H8S (148.22): C,
72.93; H, 5.44. Found: C, 73.17; H, 5.31.
[5,15-Bis(4-iod op h en yl)-10,20-bis(m esityl)p or p h in a to-
(2-)]zin c (7). To a solution of 5,15-bis(4-iodophenyl)-10,20-
bis(mesityl)porphine45 (117 mg, 0.123 mmol) in 16 mL of
CHCl3/MeOH (9:1) was added zinc acetate monohydrate (490
mg, 2.23 mmol), and the mixture was refluxed for 1 h.
Thereafter, the mixture was washed with water and dried
(Na2SO4), and the solvent was evaporated. The residue was
purified by CC (CHCl3/hexane 2:3) to yield 124 mg (99%) of 7:
UV/vis (CH2Cl2) 306 (4.18), 422 (5.68), 550 (4.31), 590 (3.65);
1H NMR (360.14 MHz) δ 1.81 (s, 12H), 2.63 (s, 6H), 7.28 (s,
4H), 7.96 and 8.07 (AA′XX′, J AX ) 8.3, 8H), 8.77 (d, J ) 4.6,
4H), 8.85 (d, J ) 4.6, 4H); FAB-MS 1014.9 (calcd average mass
for C50H38I2N4Zn 1014.07).
(t, J ) 1.5, 1H), 7.69 (t, J ) 1.5, 1H), 7.73 (t, J ) 1.5, 1H); 13
C
NMR (50.30 MHz) δ -0.2, 31.3, 65.5, 79.8, 92.9, 95.6, 96.6,
102.2, 124.6, 125.0, 134.1, 139.9, 140.0; CI-MS 383 (M + H+,
7); FAB-MS 365 (M + H+ - H2O, 100). Anal. Calcd for C16H19
-
IOSi (382.32): C, 50.27; H, 5.01. Found: C, 49.95; H, 4.87.
3,3-Dieth yl-1-(4-eth yn ylp h en yl)-1-tr ia zen e (4)43 was ob-
tained in 82% yield (109 mg) as a colorless oil, after purification
by CC (CH2Cl2/hexane 3:7), reacting 3,3-diethyl-1-[4-[(trimeth-
ylsilyl)ethynyl]phenyl]-1-triazene33 (181 mg, 0.66 mmol) with
TBAF (0.68 mmol) in THF (22 mL), as described for 1e: 1H
NMR (200.00 MHz) δ 1.27 (s, J ) 7.1, 6H), 3.07 (s, 1H), 3.77
(q, J ) 7.1, 4H), 7.36 and 7.45 (AA′XX′, J AX ) 8.8, 4H); 13C
NMR (50.30 MHz) δ 12.8, 45.0, 76.5, 84.4, 118.5, 120.4, 132.8,
151. Anal. Calcd for C12H15N3 (201.27): C, 71.61; H, 7.51; N,
20.88. Found: C, 71.82; H, 7.49; N, 20.70.
3,3-Diet h yl-1-[4-[[4-[(t r im et h ylsilyl)et h yn yl]p h en yl]-
eth yn yl]p h en yl]-1-tr ia zen e (5a ) was obtained in 81% yield
(82.9 mg), after purification by CC (CH2Cl2/hexane 1:4),
reacting 4 (55 mg, 0.273 mmol) with (4-iodophenyl)ethynyl-
trimethylsilane44 (82 mg, 0.273 mmol) in the presence of Pd-
(PPh3)4 (17.7 mg, 15 µmol) and CuI (5.7 mg, 30 µmol), in 4.3
mL of toluene/Et3N at 35 °C, as described for 1d : mp 122-
123 °C; 1H NMR (200.00 MHz) δ 0.26 (s, 9H), 1.28 (t, J ) 7.1,
6H), 3.78 (q, J ) 7.1, 4H), 7.41-7.49 (m, 8H); 13C NMR (50.30
MHz) δ -0.07, 12.9, 44.0, 88.8, 92.1, 96.0, 104.8, 119.1, 122.6,
123.8, 120.4, 131.3, 131.9, 132.3, 151.3; EI-MS 373 (M+, 18),
273 ([M - Et2N3]+, 100), 258 ([M - Et2N3 - Me]+, 73). Anal.
Calcd for C23H27N3Si (373.57): C, 73.95; H, 7.28; N, 11.25.
Found: C, 73.77; H, 7.30; N, 10.97.
[[4-[(4-Iod op h en yl)eth yn yl]p h en yl]eth yn yl]tr im eth yl-
sila n e (5b). To a thick-walled screw cap tube was added a
solution of 5a (71.7 mg, 0.192 mmol) in iodomethane (7 mL).
The tube was flushed with argon and sealed and heated to
130 °C for 12 h. The reaction mixture was cooled to room
temperature, and the solvent was removed under reduced
pressure. The crude product was purified by CC (hexane) to
yield 68.8 mg (90%) of 5b: mp 248 °C (lit.32 mp 248-250 °C).
[[4-[[4-[(Tr iisopr opylsilyl)eth yn yl]ph en yl]eth yn yl]ph en -
yl]eth yn yl]tr im eth ylsila n e (5c). Air was removed from a
solution of 5b (80 mg, 0.2 mmol) and ethynyltriisopropylsilane
(66.6 µL, 0.3 mmol) in 5 mL of Et3N by blowing argon for 30
min. Then, Pd(PPh3)2Cl2 (7 mg, 0.01 mmol) and CuI (3.8 mg,
0.02 mmol) were added before the mixture was stirred at 45
°C for 12 h. Thereafter, the solvent was removed under
reduced pressure, and the crude product was purified by CC
(hexane) to yield 90 mg (99%) of 5c.44
[[4-[(4-Eth yn ylp h en yl)eth yn yl]p h en yl]eth yn yl]tr iiso-
p r op ylsila n e (5d ) was obtained as described for 1c, reacting
5c (104.1 mg, 0.229 mmol) in 7.5 mL of THF with 0.229 mL of
aqueous NaOH (1 N) for 30 min. After purification by CC
(hexane), 75.6 mg (86%) of 5d was obtained: mp 45-46 °C.
Other analytical data agree with those given in ref 44.
1-Iod o-3-(m eth ylth io)ben zen e (6a ). A solution of 0.203
g (1.0 mmol) of 1-bromo-3-(methylthio)benzene in 6 mL of Et2O
was cooled to -75 °C before 1.5 mL of a solution of tert-
butyllithium (1.5 M in pentane, 2.25 mmol) was added drop-
wise. After the addition was complete, the reaction mixture
was stirred for 30 min at -75 °C, and then a solution of 0.8 g
(3.15 mmol) of iodine in 10 mL of Et2O was added dropwise.
The mixture was then stirred at -75 °C for 10 min and at
-20 °C for further 10 min. Ethanol was then added before
the mixture was poured into an aqueous sodium thiosulfate
solution and extracted with CH2Cl2. The organic layer was
dried (Na2SO4), the solvent was removed under reduced
pressure, and the crude product was purified by CC (CH2Cl2/
hexane 1:19) to yield 0.229 g (91%) of 6a as a colorless oil: 1H
[15-(4-Iod op h en yl)-10,20-b is(m esit yl)-5-[4-[[3-(m et h -
ylth io)p h en yl]eth yn yl]p h en yl]p or p h in a to(2-)]zin c (8a ).
Air was removed from a solution of 7 (95 mg, 94 µmol) and 6c
(13.9 mg, 94 µmol) in 8 mL of DMF/Et3N (5:1) by blowing argon
for 20 min. Then, Pd2dba3 (6.5 mg, 7.1 µmol) and AsPh3 (17.3
mg, 56.5 µmol) were added, and deaeration was continued for
10 min. Thereafter, the mixture was heated at 45 °C for 3 h.
The solvent was removed under reduced pressure, and the
crude product was purified by CC. Three fractions were
obtained: unreacted 7 (26.6 mg; 28%), 8a (39.7 mg; 41%), and
[10,20-bis(mesityl)-5,15-bis[4-[[3-(methylthio)phenyl]ethynyl]-
phenyl]porphinato(2-)]zinc (20.7 mg; 21%), which were suc-
cessively eluted with CHCl3/hexane (7:13), CHCl3/hexane (9:
11), and CHCl3/hexane (11:9). 8a : UV/vis (CH2Cl2) 422 (5.65),
1
550 (4.32), 592 (3.77); H NMR (200.00 MHz) δ 1.82 (s, 12H),
2.43 (s, 3H), 2.63 (s, 6H), 7.18-7.23 (m, 1H), 7.28 (s, 4H), 7.30
(t, J ) 7.9, 1H), 7.38-7.46 (m, 2H), 7.91 and 8.24 (AA′XX′,
J AX ) 8.1, 4H), 7.97 and 8.08 (AA′XX′, J AX ) 8.4, 4H), 8.79
and 8.86 (2 × d, J ) 4.7, 4H), 8.79 and 8.90 (2 × d, J ) 4.7,
4H); FAB-MS 1035.1 (calcd average mass for C59H45IN4SZn
1034.38).
[10,20-Bis(m esityl)-5-[4-[[3-(m eth ylth io)ph en yl]eth yn yl]-
ph en yl]-15-[4-[(tr im eth ylsilyl)eth yn yl]ph en yl]por ph in ato-
(2-)]zin c (8b). Air was removed from a solution of 8a (21
mg, 20.3 µmol) in 6 mL of DMF/Et3N (5:1) by blowing argon
for 20 min. Then, Pd2dba3 (1.4 mg, 1.5 µmol), AsPh3 (3.7 mg,
12.1 µmol), and TMSA (28 µL, 0.2 mmol) were added. There-
after, the mixture was heated at 45 °C for 3 h. The solvent
was removed under reduced pressure, and the crude product
was purified by CC (CH2Cl2/hexane 9:11 and then 11:9) to yield
16.1 mg (79%) of 8b: UV/vis (CH2Cl2) 422 (5.73), 550 (4.37),
590 (3.71); 1H NMR (200.00 MHz) δ 0.38 (s, 9H), 1.82 (s, 12H),
2.34 (s, 3H), 2.63 (s, 6H), 7.13 (m, 1H), 7.28 (s, 4H), 7.28 (m,
(43) Xu, Z.; Kahr, M.; Walker, K. L.; Wilkins, C. L.; Moore, J . S. J .
Am. Chem. Soc. 1994, 116, 4537-4550.
(44) Lavastre, O.; Ollivier, L.; Dixneuf, P. H. Tetrahedron 1996, 52,
5495-5504.
1H), 7.32 (m, 1H), 7.41 (m, 1H), 7.86 and 8.19 (AA′XX′, J AX
)

Synthesis of Benzene-Centered Porphyrin Trimers
J . Org. Chem., Vol. 63, No. 16, 1998 5577
8.4, 4H), 7.91 and 8.24 (AA′XX′, J AX ) 8.2, 4H), 8.78 and 8.85
(2 × d, J ) 4.7, 4H), 8.80 and 8.90 (2 × d, J ) 4.7, 4H); FAB-
MS 1004.9 (calcd average mass for C64H54N4SSiZn 1004.69).
Tr ip or p h yr in 10a . Air was removed from a solution of
1c (2.04 mg, 13.6 µmol) and 9a 47 (39.1 mg, 52.8 µmol) in 9 mL
of DMF/Et3N (5:1) by blowing argon for 20 min. Then, Pd-
(PPh3)4 (7.7 mg, 6.7 µmol) was added, and deaeration was
continued for 10 min before the mixture was heated at 45 °C
for 20 h. The solvent was removed under reduced pressure,
and the crude product was purified by CC (CHCl3/hexane:
gradient from 3:2 to 3:1) to yield 12.0 mg (44%) of 10a : UV/
vis (CH2Cl2) 288 (4.98), 374 (4.82), 420 (6.09), 516 (4.70), 550
(4.39), 590 (4.13); 1H NMR (360.14 MHz) δ -2.76 (s, 6H), 7.73-
7.82 (m, 27H), 8.03 and 8.29 (AA′XX′, J AX ) 8.4, 12H), 8.04 (s,
3H, H-benzenetriyl), 8.21-8.25 (m, 18H), 8.86 (s, 12H), 8.90
(s, 12H); ES+-MS (in THF/MeOH) m/z 1989.3 ([MH]+), 994.9
([MH2]2+) (calcd average mass for C144H90N12: 1988.38).
[15-(4-E t h y n y lp h e n y l)-10,20-b is (m e s it y l)-5-[4-[[3-
(m e t h y lt h i o )p h e n y l]e t h y n y l]p h e n y l]p o r p h i n a t o -
(2-)]zin c (8c) was obtained as described for 1c, reacting 8b
(13.5 mg, 13.4 µmol) in 4 mL of THF with 2.5 mL of NaOH (1
N) for 5 h. After purification by CC (CHCl3/hexane 1:1 then
3:2), 10.9 mg (87%) of 8c was obtained: UV/vis (CH2Cl2) 422
(5.67), 510 (3.77), 549 (4.35), 590 (3.78); 1H NMR (360.14 MHz)
δ 1.83 (s, 12H), 2.39 (s, 3H), 2.63 (s, 6H), 3.30 (s, 1H), 7.16
(ddd, J ) 7.8, 1.9, 1.1, 1H), 7.28 (s, 4H), 7.29 (t, J ) 7.8, 1H),
7.38 (t, J ) 1.9), 7.41 (dt, J ) 7.8, 1.1, 1H), 7.87 and 8.20
(AA′XX′, J AX ) 8.4, 4H), 7.91 and 8.24 (AA′XX′, J AX ) 8.3, 4H),
8.77 and 8.84 (2 × d, J ) 4.6, 4H), 8.82 and 8.88 (2 × d, J )
4.6, 4H); FAB-MS 932.7 (calcd average mass for C61H46N4SZn
932.51).
[15-[4-[[4-[(4-Iodoph en yl)eth yn yl]ph en yl]eth yn yl]ph en -
yl]-10,20-bis(m esityl)-5-[4-[[3-(m eth ylth io)ph en yl]eth yn yl]-
p h en yl]p or p h in a to(2-)]zin c (8d ). Air was removed from
a solution of 8c (12.1 mg, 13.0 µmol) and 4,4′-diiodotolane27,46
(28.5 mg, 66.3 µmol) in 7 mL of DMF/Et3N (5:1) by blowing
argon for 20 min. Then, Pd(PPh3)4 (2.4 mg, 2.1 µmol) was
added, and deaeration was continued for 10 min before the
mixture was heated at 45 °C for 18 h. The solvent was
removed under reduced pressure, and the crude product was
purified by CC (CHCl3/hexane: gradient from 3:7 to 11:9) to
yield 14.2 mg (89%) of 8d : UV/vis (CH2Cl2) 320 (4.78), 423
(5.70), 550 (4.40), 590 (3.87); 1H NMR (360.14 MHz) δ 1.83 (s,
12H), 2.46 (s, 3H), 2.63 (s, 6H), 7.21 (ddd, J ) 8.0, 1.7, 1.1,
1H), 7.28 and 7.72 (AA′XX′, J AX ) 8.6, 4H), 7.29 (s, 4H), 7.31
(t, J ) 8.0, 1H), 7.43 (ddd, J ) 8.0, 1.7, 1.1, 1H), 7.44 (t, J )
1.7, 1H), 7.57 and 7.65 (AA′XX′, J AX ) 8.6, 4H), 7.92 and 8.24
(2 × AA′XX′, J AX ) 8.2, 2 × 4H), 8.80 (2 × d, J ) 4.6, 4H),
8.90 (2 × d, J ) 4.6, 4H); FAB-MS 1235.2 (calcd average mass
for C75H53IN4SZn 1234.62).
Tr ip or p h yr in 10b was obtained in 56% yield (11.1 mg),
after purification by CC (CHCl3/hexane: gradient from 3:7 to
3:2), reacting 1c (1.37 mg, 9.1 µmol) with 9b27 (29.1 mg, 36.5
µmol) in the presence of Pd(PPh3)4 (4.7 mg, 4.1 µmol), in 6 mL
of DMF/Et3N, as described for 10a : UV/vis (CH2Cl2) 293 (5.04),
416 (5.85), 528 (4.74); 1H NMR (500.13 MHz) δ 7.65-7.73 (m,
27H), 7.92 and 8.06 (AA′XX′, J AX ) 8.2, 12H), 7.96 (s, 3H,
H-benzenetriyl), 8.00-8.04 (m, 18H), 8.75 (s, 12H), 8.79 (2 ×
d, J ) 4.7, 12H); FAB-MS 2158.7 (calcd average mass for
C
144H84N12Ni3: 2158.49).
Tr ip or p h yr in 10c was obtained in 65% yield (20.3 mg),
after purification by two successive CC (CHCl3/hexane 7:3),
reacting 1c (2.15 mg, 14.3 µmol) with 9c27 (46 mg, 57.2 µmol)
in the presence of Pd(PPh3)4 (7.4 mg, 6.4 µmol), in 9 mL DMF/
Et3N, as described for 10a : UV/vis (CH2Cl2) 298 (4.98), 422
(6.14), 548 (4.81), 589 (4.20); UV/vis (benzene) 292 (4.97), 425
1
(6.12), 550 (4.81), 590 (4.22); EMS (benzene) λem 602, 650; H
NMR (500.13 MHz) δ 7.73-7.80 (m, 27H), 8.02 and 8.29
(AA′XX′, J AX ) 8.2, 12H), 8.04 (s, 3H, H-benzenetriyl), 8.22-
8.25 (m, 18H), 8.96 (s, 12H), 9.00 and 9.01 (2 × d, J ) 4.7,
12H); ES-MS 2179.0 (calcd average mass for C144H84N12Zn3
2178.47); FAB-MS 2178.3 (M+), 1089 (M2+).
[10,20-Bis(m esityl)-5-[4-[[3-(m eth ylth io)ph en yl]eth yn yl]-
p h en yl]-15-[4-[[4-[[4-[(tr iisop r op ylsilyl)eth yn yl]p h en yl]-
eth yn yl]ph en yl]eth yn yl]ph en yl]por ph in ato(2-)]zin c (8e).
Air was removed from a solution of 8a (23.1 mg, 22.3 µmol)
and 5d (17.0 mg, 44.4 µmol) in 6 mL of DMF/Et3N (5:1) by
blowing argon for 20 min. Then, Pd2dba3 (1.5 mg, 1.6 µmol)
and AsPh3 (4.1 mg, 13.4 µmol) were added, and deaeration was
continued for 10 min before the mixture was heated at 45 °C
for 4 h. The solvent was removed under reduced pressure,
and the crude product was purified by CC (CHCl3/hexane:
gradient from 2:8 to 2:3) to yield 21.6 mg (75%) of 8e: UV/vis
(CH2Cl2) 266 (4.99), 326 (4.88), 424 (5.72), 550 (4.44), 588
Tr ip or p h yr in 10d . Meth od A. 10d was obtained in 66%
yield (8.4 mg), after purification by two successive CC (CHCl3/
hexane gradient from 3:2 to 7:3), reacting 1c (0.69 mg, 4.6
µmol) with 9d 27 (18.5 mg, 18.4 µmol) in the presence of Pd-
(PPh3)4 (2.4 mg, 2.1 µmol), in 6 mL of DMF/Et3N, as described
for 10a . Meth od B. Air was removed from a solution of 1e
(3.11 mg, 4.14 µmol) and 9c (13.2 mg, 16.5 µmol) in 2.8 mL of
DMF/Et3N (5:1) by blowing argon for 20 min. Then, Pd2dba3
(0.46 mg, 0.5 µmol) and AsPh3 (1.24 mg, 4.05 µmol) were added,
and deaeration was continued for 10 min, before the mixture
was heated at 30 °C during 4 h. Then, the same amounts of
Pd2dba3 and AsPh3 were added again, and stirring was
continued for 2 h. The solvent was removed under reduced
pressure, and the crude product was purified by CC (CHCl3/
hexane: gradient from 3:7 to 4:1) to yield 7.0 mg (61%) of
10d : UV/vis (CH2Cl2) 349 (5.27), 422 (6.13), 549 (4.75), 589
(4.18); UV/vis (benzene) 342 (5.27), 425 (6.11), 550 (4.79), 590
1
(3.85); H NMR (360.14 MHz) δ 1.15 (m, 21H), 1.83 (s, 12H),
2.35 (s, 3H), 2.63 (s, 6H), 7.13 (m, 1H), 7.28 (s, 4H), 7.33 (m,
1H), 7.40 (m, 1H), 7.43 (m, 1H), 7.49 (s, 4H), 7.57 and 7.65
(AA′XX′, J AX ) 8.6, 4H), 7.92 and 8.24 (2 × AA′XX′, J AX ) 8.3,
2 × 4H), 8.80 (d, J ) 4.6, 4H), 8.90 and 8.91 (2 × d, J ) 4.6,
4H); FAB-MS 1289.7 (calcd average mass for C86H74N4SSiZn
1289.08).
1
(4.23); EMS (benzene) λem 602, 650; H NMR (500.13 MHz) δ
7.55 and 7.57 (AA′XX′, J AX ) 8.6, 12H), 7.61 and 7.68 (AA′XX′,
J AX ) 8.4, 12H), 7.71 (s, 3H, H-benzenetriyl), 7.73-7.81 (m,
27H), 7.95 and 8.25 (AA′XX′, J AX ) 8.3, 12H), 8.21-8.24 (m,
18H), 8.96 (s, 12H), 8.97 and 8.98 (2 × d, J ) 4.7, 12H); FAB-
MS 2778.8 (calcd avg mass for C192H108N12Zn3 2779.19).
[15-[4-[[4-[(4-Eth yn ylp h en yl)eth yn yl]p h en yl]eth yn yl]-
p h en yl]-10,20-bis(m esityl)-5-[4-[[3-(m eth ylth io)p h en yl]-
eth yn yl]p h en yl]p or p h in a to(2-)]zin c (8f). To a solution
of 8e (20 mg, 15.5 µmol) in 2 mL of THF was added TBAF (1
M in THF, 16 µL, 16 µmol), and the mixture was stirred at 20
°C for 1 h. A few grains of CaCl2 were added to remove any
excess of fluoride (cf. ref 42) before the solvent was evaporated,
and the crude product was purified by CC (CHCl3/hexane:
gradient from 2:8 to 2:3) to yield 9.4 mg (53%) of 8f: UV/vis
(CH2Cl2) 324 (4.81), 424 (5.72), 550 (4.41), 590 (3.80); 1H NMR
(360.14 MHz) δ 1.83 (s, 12H), 2.46 (s, 3H), 2.63 (s, 6H), 3.20
(s, 1H), 7.21 (m, 1H), 7.28 (s, 4H), 7.32 (m, 1H), 7.43 (m, 2H),
7.51 (m, 4H), 7.58 and 7.66 (AA′XX′, J AX ) 8.3, 4H), 7.92 and
8.24 (2 × AA′XX′, J AX ) 8.3, 2 × 4H), 8.80 (d, J ) 4.6, 4H),
8.90 (2 × d, J ) 4.6, 4H); FAB-MS 1133.3 (calcd avg mass for
Tr ip or p h yr in 10e was obtained in 44% yield (6.0 mg), after
purification by CC (CHCl3/hexane: gradient from 1:1 to
CHCl3), reacting 1e (3.03 mg, 4.04 µmol) with 9d (17.6 mg,
17.6 µmol) in the presence of Pd2dba3 (0.48 mg, 0.52 µmol) and
AsPh3 (1.27 mg, 4.15 µmol), in 3.2 mL of DMF/Et3N, as
described for 10d (method B): UV/vis (CHCl3) 364 (5.44), 424
(6.02), 552 (4.66), 592 (4.24), 598 (4.22); 1H NMR (500.13 MHz)
δ 7.52-7.58 (m, 36 H), 7.61 and 7.68 (AA′XX′, J AX ) 8.3, 12H),
7.69 (s, 3H, H-benzenetriyl), 7.73-7.80 (m, 27H), 7.94 (appar-
ent d, J ) 8.1, 6H), 8.21-8.25 (m, 24H), 8.95 (s, 12H), 8.96
and 8.98 (2 × d, J ) 4.7, 12H); ES+-MS (in CHCl3/MeOH/
HCOOH) m/z 1595.8 ([M - 3Zn + 8H]2+), 1064.2 ([M - 3Zn +
C
77H54N4SZn 1132.74).
(45) Lee, C.-H.; Lindsey, J . S. Tetrahedron 1994, 50, 11427-11440.
(46) Novikov, A. N.; Grigor’ev, M. G. Zh. Org. Khim. 1978, 14, 1790.
(47) Syrbu, S. A.; Semeikin, A. S.; Berezin, B. D. Khim. Geterotsikl.
Soedin. 1990, 11, 1507-1509.

5578 J . Org. Chem., Vol. 63, No. 16, 1998
Mongin et al.
9H]3+) (calcd average mass for C240H132N12Zn3 3379.90). Atomic
absorption calcd: Zn, 5.80. Found: Zn, 5.76.
[10,20-Bis(m esityl)-5-[4-[[3-(m eth ylth io)ph en yl]eth yn yl]-
ph en yl]-15-[4-[[5-[[4[[4-[(tr iisopr opylsilyl)eth yn yl]ph en yl]-
eth yn yl]ph en yl]eth yn yl]-3-[(tr im eth ylsilyl)eth yn yl]ph en -
yl]eth yn yl]ph en yl]por ph in ato(2-)]zin c (13a) was obtained
in 81% yield (10.8 mg), after purification by CC (CHCl3/
hexane: gradient from 2:3 to 1:1), reacting 12 (6.1 mg, 8.9
µmol) with 8c (10.0 mg, 10.7 µmol) in the presence of Pd(PPh3)4
(1.5 mg, 1.3 µmol), in 2 mL of DMF/Et3N, as described for
10a : UV/vis (CH2Cl2) 334 (4.98), 422 (5.74), 550 (4.42), 592
Tr ip or p h yr in 11a was obtained in 57% yield (7.6 mg), after
purification by CC (CHCl3/hexane: gradient from 2:3 to 7:3),
reacting 1c (0.70 mg, 4.7 µmol) with 8a (19.5 mg, 18.9 µmol)
in the presence of Pd(PPh3)4 (2.5 mg, 2.2 µmol), in 12 mL of
DMF/Et3N, as described for 10a : UV/vis (CH2Cl2) 294 (5.19),
425 (6.16), 550 (4.91), 590 (4.37); 1H NMR (500.13 MHz) δ 1.85
(s, 36H), 2.51 (s, 9H), 2.64 (s, 18H), 7.25 (ddd, J ) 8.0, 1.9,
1.1, 3H), 7.30 (2 × s, 12H), 7.33 (t, J ) 8.0, 3H), 7.44 (ddd, J
) 7.7, 1.5, 1.1, 3H), 7.49 (t, J ) 1.5, 3H), 7.93 and 8.25 (AA′XX′,
J AX ) 8.4, 12H), 8.02 and 8.31 (AA′XX′, J AX ) 8.5, 12H), 8.03
(s, 3H, H-benzenetriyl), 8.81 and 8.91 (2 × d, J ) 4.6, 12H),
8.83 and 8.95 (2 × d, J ) 4.6, 12H); ES+-MS (in CHCl3/MeOH)
m/z 2870.4 ([MH]+), 1435.1 ([MH2]2+), 956.5 ([MH3]3+) (calcd
average mass for C189H138N12S3Zn3 2869.59).
Tr ip or p h yr in 11b. Meth od A. 11b was obtained in 66%
yield (5.8 mg), after purification by CC (CHCl3/hexane gradient
from 1:1 to 7:3), reacting 1c (0.38 mg, 2.5 µmol) with 8d (12.6
mg, 10.2 µmol) in the presence of Pd(PPh3)4 (1.3 mg, 1.1 µmol),
in 6.5 mL of DMF/Et3N, as described for 10a . Meth od B. 11b
was obtained in 22% yield (1.5 mg), after purification by CC
(CHCl3/hexane: gradient from 1:1 to 7:3), reacting 8f (9.2 mg,
8.1 µmol) with 1a (0.90 mg, 1.97 µmol) in the presence of Pd-
(PPh3)4 (1 mg, 0.9 µmol), in 4 mL of DMF/Et3N, as described
for 10a . Meth od C. 11b was prepared as described for 10d
(method B), reacting 1e (2.12 mg, 2.82 µmol) with 8a (11.7
mg, 11.3 µmol) in the presence of Pd2dba3 (0.38 mg, 0.41 µmol)
and AsPh3 (1.02 mg, 3.33 µmol), in 2.3 mL of DMF/Et3N at 30
°C for 5 h. After purification by CC (CHCl3/hexane: gradient
from 2:3 to 7:3), 4.7 mg (48%) was obtained: UV/vis (CH2Cl2)
342 (5.35), 4.24 (6.14), 510 (4.27), 550 (4.86), 592 (4.35); 1H
NMR (500.13 MHz) δ 1.84 (s, 36H), 2.53 (s, 9H), 2.64 (s, 18H),
7.26 (ddd, J ) 7.9, 1.9, 1.1, 3H), 7.29 (2 × s, 12H), 7.34 (dd, J
) 7.9, 7.7, 3H), 7.44 (dt, J ) 7.7, 1.1, 3H), 7.50 (t, J ) 1.9,
3H), 7.57 and 7.59 (AA′XX′, J AX ) 8.7, 12H), 7.61 and 7.68
(AA′XX′, J AX ) 8.4, 12H), 7.72 (s, 3H, H-benzenetriyl), 7.93
and 8.25 (AA′XX′, J AX ) 8.1, 12H), 7.94 and 8.26 (AA′XX′, J AX
) 8.1, 12H), 8.81 and 8.90 (2 × d, J ) 4.6, 12H), 8.81 and 8.91
(2 × d, J ) 4.6, 12H); ES+-MS (in CHCl3/MeOH) m/z 1735.1
([MH2]2+) (calcd average mass for C237H162N12S3Zn3 3470.32).
1
(3.84); H NMR (360.14 MHz) δ 0.30 (s, 9H), 1.14 (m, 21H),
1.83 (s, 12H), 2.47 (s, 3H), 2.64 (s, 6H), 7.23 (ddd, J ) 7.4, 1.4,
1.1, 1H), 7.29 (s, 4H), 7.32 (t, J ) 7.4, 1H), 7.43 (dt, J ) 7.4,
1.1, 1H), 7.44 (t, J ) 1.4, 1H), 7.47 (s, 4H), 7.53 (s, 4H), 7.66,
7.75 and 7.78 (3 × t, J ) 1.4, 3 × 1H, H-4, H-2 and H-6
benzenetriyl, respectively), 7.91 and 8.25 (AA′XX′, J AX ) 8.3,
4H), 7.92 and 8.24 (AA′XX′, J AX ) 8.3, 4H), 8.80 (2 × d, J )
4.6, 4H), 8.90 (2 × d, J ) 4.6, 4H); FAB-MS 1484.8 (calcd
average mass for C99H86N4SSi2Zn 1485.41).
[15-[4-[[5-[[4-[(4-Eth yn ylp h en yl)eth yn yl]p h en yl]eth yn -
yl]-3-(eth yn yl)ph en yl]eth yn yl]ph en yl]-10,20-bis(m esityl)-
5-[4-[[3-(m eth ylth io)p h en yl]eth yn yl]p h en yl]p or p h in a to-
(2-)]zin c (13b) was obtained in 95% yield (8.2 mg), as
described for 8f, from 13a (10.2 mg, 6.9 µmol), after 10 min
reaction time and purification by CC (CHCl3/hexane 11:9): UV/
1
vis (CH2Cl2) 330 (4.90), 422 (5.68), 550 (4.38), 592 (3.82); H
NMR (360.14 MHz) δ 1.83 (s, 12H), 2.51 (s, 3H), 2.64 (s, 6H),
3.17 (s, 1H), 3.19 (s, 1H), 7.24 (m, 1H), 7.29 (s, 4H), 7.33 (t, J
) 7.7, 1H), 7.44 (dt, J ) 7.7, 1.4, 1H), 7.49 (s, 4H), 7.52 (t, J
) 1.4, 1H), 7.54 (s, 4H), 7.67, 7.76 and 7.82 (3 × t, J ) 1.5, 3
× 1H, H-4, H-2 and H-6 benzenetriyl, respectively), 7.92 and
8.24 (2 × AA′XX′, J AX ) 8.3, 2 × 4H), 8.80 and 8.90 (2 × d, J
) 4.6, 4H), 8.81 and 8.90 (2 × d, J ) 4.6, 4H); FAB-MS 1255.7
(calcd average mass for C87H58N4SZn 1256.89).
Tr ip or p h yr in 14 was obtained in 67% yield (6.7 mg), after
purification by two successive CC (CHCl3/hexane: gradient
from 1:1 to 7:3), reacting 13b (3.6 mg, 2.9 µmol) with 8d (8.9
mg, 7.2 µmol) in the presence of Pd(PPh3)4 (1 mg, 0.9 µmol),
in 5.5 mL of DMF/Et3N, as described for 10a : UV/vis (CH2-
Cl2) 358 (5.23), 424 (6.07), 550 (4.77), 592 (4.23); 1H NMR
(500.13 MHz) δ 1.84 (s, 24H), 1.85 (s, 12H), 2.54 (s, 9H), 2.64
(s, 12H), 2.65 (s, 6H), 7.27 (ddd, J ) 8.0, 1.9, 1.1, 3H), 7.29 (s,
8H), 7.30 (s, 4H), 7.34 (t, J ) 7.6, 3H), 7.45 (ddd, J ) 7.6, 1.9,
1.1, 3H), 7.52 (t, J ) 1.9, 3H), 7.55 and 7.56 (2 × s, 8H), 7.58
(m, 4H), 7.60 (s, 4H), 7.60 and 7.67 (AA′XX′, J AX ) 8.4, 4H),
7.62 and 7.68 (AA′XX′, J AX ) 8.4, 4H), 7.76, 7.83 and 7.85 (3
× t, J ) 1.5, 3 × 1H, H-benzenetriyl), 7.92 and 8.24 (AA′XX′,
J AX ) 8.1, 8H), 7.93 and 8.25 (AA′XX′, J AX ) 8.3, 4H), 7.94
and 8.25 (2 × AA′XX′, J AX ) 8.2, 8H), 7.95 and 8.27 (AA′XX′,
J AX ) 8.2, 4H), 8.803 and 8.900 (2 × d, J ) 4.7, 8H), 8.806
and 8.900 (2 × d, J ) 4.7, 4H), 8.807 and 8.904 (2 × d, J )
4.7, 4H), 8.810 and 8.906 (2 × d, J ) 4.6, 4H), 8.820 and 8.920
(2 × d, J ) 4.7, 4H); ES+-MS (in CHCl3/MeOH) m/z 1640.9
([M - 3Zn + 8H]2+), 1094.4 ([M - 3Zn + 9H]3+), 821.0 ([M -
3Zn + 10H]4+) (calcd average mass for C237H162N12S3Zn3
3470.32). Atomic absorption calcd: Zn, 5.65. Found: Zn, 5.55.
Tr ip or p h yr in 11c was obtained in 54% yield (6.0 mg), after
purification by CC (CHCl3/hexane: gradient from 9:11 to 4:1),
reacting 1e (2.04 mg, 2.72 µmol) with 8d (13.7 mg, 11.1 µmol)
in the presence of Pd2dba3 (0.57 mg, 0.62 µmol) and AsPh3 (1.49
mg, 4.87 µmol), in 3.8 mL of DMF/Et3N, as described for 10d
(method B): UV/vis (CH2Cl2) 366 (5.43), 424 (6.01), 552 (4.72),
1
584 (4.26), 592 (4.29); H NMR (500.13 MHz) δ 1.84 (s, 36H),
2.53 (s, 9H), 2.64 (s, 18H), 7.26 (m, 3H), 7.30 (s, 12H), 7.33 (t,
J ) 7.7, 3H), 7.44 (dt, J ) 7.7, 1.4, 3H), 7.51 (t, J ) 1.9, 3H),
7.52-7.57 (m, 36H), 7.60 and 7.68 (AA′XX′, J AX ) 8.3, 12H),
7.69 (s, 3H), 7.92 and 8.23 (AA′XX′, J AX ) 8.1, 12H), 7.93 and
8.24 (AA′XX′, J AX ) 8.1, 12H), 8.80 and 8.90 (2 × d, J ) 4.7,
12H), 8.80 and 8.90 (2 × d, J ) 4.7, 12H); ES+-MS (in CHCl3/
MeOH/HCOOH) m/z 1294.5 ([M - 3Zn + 9H]3+) (calcd average
mass for
C
285H186N12S3Zn3 4071.00). Atomic absorption
[2-Meth yl-4-[5-[(tr im eth ylsilyl)eth yn yl]-3-[[4-(10,15,20-
tr iph en yl-21H,23H-por ph in -5-yl)ph en yl]eth yn yl]ph en yl]-
3-bu tyn -2-ola to(2-)-N21,N22,N23,N24]zin c (15a ) was obtained
in 92% yield (32.3 mg), after purification by CC (CHCl3/hexane
7:3), reacting 3 (14 mg, 36.6 µmol) with [5-(4-ethynylphenyl)-
10,15,20-triphenylporphinato(2-)]zinc27 (28.3 mg, 40.3 µmol)
in the presence of Pd(PPh3)4 (6.3 mg, 5.5 µmol), in 9 mL of
DMF/Et3N, as described for 10a : UV/vis (CH2Cl2) 290 (4.56),
421 (5.71), 510 (3.68), 549 (4.35), 589 (3.79); 1H NMR (500.13
MHz) δ 0.28 (s, 9H), 1.62 (s, 6H), 1.97 (s, 1H), 7.55, 7.66 and
7.72 (3 × t, J ) 1.6, 3 × 1H, H-6, H-4 and H-2 benzenetriyl,
respectively), 7.73-7.80 (m, 9H), 7.90 and 8.22 (AA′XX′, J AX
) 8.3, 4H), 8.20-8.24 (m, 6H), 8.95 (s, 4H), 8.95 and 8.97 (2 ×
d, J ) 4.7, 4H); FAB-MS 956.4 (calcd average mass for
calcd: Zn, 4.82. Found: Zn, 4.77.
[[4-[[4-[[5-Iodo-3-[(tr im eth ylsilyl)eth yn yl]ph en yl]eth yn -
yl]ph en yl]eth yn yl]ph en yl]eth yn yl]tr iisopr opylsilan e (12).
Air was removed from a solution of 2 (39.6 mg, 92.9 µmol) and
5d (32.0 mg, 83.6 µmol) in 6 mL of pyridine/Et3N (1:1) by
blowing argon for 20 min. Then, Pd(PPh3)4 (5.4 mg, 4.7 µmol)
and CuI (1.8 mg, 9.4 µmol) were added, and the mixture was
stirred at 35 °C for 2 h. The solvent was removed under
reduced pressure, and the residue was purified by CC (gradient
from hexane to CH2Cl2/hexane 1:24) to yield 34.8 mg (61%) of
12: 1H NMR (200.00 MHz) δ 0.25 (s, 9H), 1.14 (m, 21H), 7.46
(s, 4H), 7.49 (m, 4H), 7.58 (t, J ) 1.5, 1H), 7.77 (t, J ) 1.5,
1H), 7.81 (t, J ) 1.5, 1H); 13C NMR (50.30 MHz) δ -0.2, 11.3,
18.7, 88.8, 90.7, 90.8, 91.3, 93.0, 96.8, 102.2, 106.6, 122.5, 122.8,
123.4, 123.6, 124.9, 125.2, 131.4, 131.6, 132.0, 134.0, 139.9,
140.2; FAB-MS 681 (M+, 78), 637 ([M - i-Pr]+, 85), 595 ([M -
2i-Pr]+, 50), 567 (100). Anal. Calcd for C38H41ISi2 (680.83):
C, 67.04; H, 6.07. Found: C, 67.12; H, 6.11.
C
62H46N4OSiZn 956.54).
[4-[5-Eth yn yl-3-[[4-(10,15,20-tr iph en yl-21H,23H-por ph in -
5-yl)p h en yl]et h yn yl]p h en yl]-2-m et h yl-3-b u t yn -2-ola t o-
(2-)-N21,N22,N23,N24]zin c (15b) was obtained in 94% yield
(25.7 mg), as described for 8f, from 15a (29.5 mg, 30.8 µmol)

Synthesis of Benzene-Centered Porphyrin Trimers
J . Org. Chem., Vol. 63, No. 16, 1998 5579
after 3 h reaction time and purification by CC (CHCl3/hexane
4:1): UV/vis (CH2Cl2) 290 (4.57), 421 (5.72), 512 (3.67), 548
(4.36), 589 (3.74); H NMR (500.13 MHz) δ 1.62 (s, 6H), 1.97
(s, 4H); signals for H-phenyl, H-phenylene, and â-H on CuTPP
are either very broad or unperceptible; FAB-MS 2172.0 (calcd
average mass for C144H84CuN12NiZn 2169.98).
1
(s, 1H), 3.14 (s, 1H), 7.55, 7.70 and 7.72 (3 × t, J ) 1.6, 3 ×
1H, H-6, H-4 and H-2 benzenetriyl, respectively), 7.73-7.80
(m, 9H), 7.91 and 8.23 (AA′XX′, J AX ) 8.3, 4H), 8.20-8.24 (m,
6H), 8.95 (s, 4H), 8.95 and 8.97 (2 × d, J ) 4.7, 4H). FAB-
MS: 884.2 (calcd average mass for C59H38N4OZn: 884.36).
Tr ip or p h yr in 17c. To a solution of 17b (7.5 mg, 3.5 µmol)
in CHCl3 (5 mL) was added TFA (0.5 mL), and the mixture
was stirred at 20 °C for 2 h. Then the mixture was poured
into saturated aqueous Na2CO3, and the organic layer was
separated, washed with water, and dried (Na2SO4) before the
solvent was evaporated. The residue was purified by CC
(CHCl3/hexane 3:2 then 3:1) to yield 7.1 mg (97%) of 17c: UV/
vis (CH2Cl2) 294 (5.13), 418 (6.04), 532 (4.70); UV/vis (benzene)
290 (4.92), 420 (6.02), 536 (4.60); EMS (benzene) λem 656, 720;
1H NMR (500.13 MHz) δ -2.76 (s, 2H), 7.67-7.72 (m, 9H),
7.75-7.80 (m, 9H), 7.93 and 8.07 (AA′XX′, J AX ) 7.8, 4H),
7.96-8.04 (m, 3H, H-benzenetriyl), 8.00 and 8.27 (AA′XX′, J AX
) 7.8, 4H), 8.01-8.03 (m, 6H), 8.22-8.24 (m, 6H), 8.76 (s, 4H),
8.79 (s, 4H), 8.86 (s, 4H), 8.89 (s, 4H); signals for H-phenyl,
H-phenylene and â-H on CuTPP are either very broad or
Dip or p h yr in 16a was obtained in 86% yield (36.3 mg),
after purification by CC (CH2Cl2/hexane: gradient from 7:3
to 4:1), reacting 15b (24 mg, 27.1 µmol) with 9b (28.1 mg, 35.2
µmol) in the presence of Pd(PPh3)4 (4.7 mg, 4.1 µmol), in 12
mL of DMF/Et3N, as described for 10a : UV/vis (CH2Cl2) 291
1
(4.87), 420 (5.89), 534 (4.49), 547 (4.54), 590 (4.03); H NMR
(500.13 MHz) δ 1.70 (s, 6H), 2.05 (s, 1H), 7.74 (t, J ) 1.6, 1H,
H-benzenetriyl between NiTPP and alcohol), 7.76 (t, J ) 1.6,
1H, H-benzenetriyl between ZnTPP and alcohol), 7.91 (t, J )
1.6, 1H, H-benzenetriyl between NiTPP and ZnTPP), 7.66-
7.73 (m, 9H), 7.74-7.81 (m, 9H), 7.89 and 8.05 (AA′XX′, J AX
) 8.4, 4H), 7.96 and 8.26 (AA′XX′, J AX ) 8.3, 4H), 8.00-8.03
(m, 6H), 8.21-8.24 (m, 6H), 8.75 (s, 4H), 8.77 and 8.78 (2 × d,
J ) 4.9, 4H), 8.96 (s, 4H), 8.98 and 8.99 (2 × d, J ) 4.7, 4H);
FAB-MS 1554.0 (calcd average mass for C103H64N8NiOZn
1553.79).
unperceptible; FAB-MS 2107.0 (calcd average mass for C144H86
CuN12Ni 2106.62).
-
Dip or p h yr in 18a was obtained in 61% yield (13.8 mg), as
described for 8e, reacting 2 (4.7 mg, 11.1 µmol) with 8c (31.1
mg, 33.4 µmol) in the presence of Pd2dba3 (1.17 mg, 1.28 µmol)
and AsPh3 (3.13 mg, 10.22 µmol), in 6.4 mL of DMF/Et3N at
30 °C after 6 h reaction time and purification by CC (CHCl3/
hexane: gradient from 1:1 to 3:2): UV/vis (CH2Cl2) 266 (4.98),
294 (4.97), 422 (5.93), 550 (4.64), 590 (3.99), 594 (3.99); 1H
NMR (360.14 MHz) δ 0.33 (s, 9H), 1.84 (s, 24H), 2.51 (s, 6H),
2.64 (s, 12H), 7.25 (ddd, J ) 7.6, 1.5, 1.2, 2H), 7.29 (s, 8H),
7.32 (t, J ) 7.6, 2H), 7.44 (dt, J ) 7.6, 1.5, 2H), 7.49 (t, J )
1.5, 2H), 7.81 (d, J ) 1.8, 2H, H-benzenetriyl), 7.92 and 8.24
(AA′XX′, J AX ) 8.2, 8H), 7.93 (t, J ) 1.8, 1H, H-benzenetriyl),
7.95 and 8.27 (AA′XX′, J AX ) 8.2, 8H), 8.80 and 8.90 (2 × d, J
) 4.6, 8H), 8.81 and 8.91 (2 × d, J ) 4.6, 8H); ES+-MS (in
CHCl3/MeOH/HCOOH): 1973.0 ([M - Zn + 3H]+), 1909.5 ([M
- 2Zn + 5H]+), 955.1 ([M - 2Zn + 6H]2+) (calcd average mass
for C133H102N8S2SiZn2 2035.29).
Dip or p h yr in 18b was obtained in 80% yield (10.6 mg), as
described for 8f, from 18a (13.8 mg, 6.8 µmol) after 1 min
reaction time and purification by CC (CHCl3/hexane: gradient
from 3:2 to 7:3): UV/vis (CH2Cl2) 262 (4.89), 291 (4.97), 422
(5.87), 550 (4.62), 584 (4.03), 592 (4.08); 1H NMR (360.14 MHz)
δ 1.84 (s, 24H), 2.53 (s, 6H), 2.64 (s, 12H), 3.22 (s, 1H), 7.26
(ddd, J ) 7.6, 1.5, 1.2, 2H), 7.29 (s, 8H), 7.33 (t, J ) 7.6, 2H),
7.44 (dt, J ) 7.6, 1.5, 2H), 7.50 (t, J ) 1.5, 2H), 7.82 (d, J )
1.5, 2H, H-benzenetriyl), 7.92 and 8.24 (AA′XX′, J AX ) 8.2, 8H),
7.96 and 8.27 (AA′XX′, J AX ) 8.2, 8H), 7.97 (t, J ) 1.5, 1H,
H-benzenetriyl), 8.80 and 8.90 (2 × d, J ) 4.4, 8H), 8.82 and
8.92 (2 × d, J ) 4.6, 8H); ES+-MS (in CHCl3/MeOH/HCOOH)
1837.2 ([M - 2Zn + 5H]+), 919.1 ([M - 2Zn + 6H]2+) (calcd
average mass for C130H94N8S2Zn2 1963.11).
Dip or p h yr in 18c was obtained in 82% yield (9.9 mg), after
purification by CC (CHCl3/hexane: gradient from 1:1 to 7:3),
reacting 18b (10.5 mg, 5.3 µmol) with 4,4′-diiodotolane (42.3
mg, 98.4 µmol) in the presence of Pd(PPh3)4 (3.2 mg, 2.8 µmol),
in 6 mL of DMF/Et3N, as described for 8d : UV/vis (CH2Cl2)
298 (5.00), 422 (5.88), 550 (4.59), 590 (3.94); 1H NMR (360.14
MHz) δ 1.84 (s, 24H), 2.55 (s, 6H), 2.64 (s, 12H), 7.26 (m, 2H),
7.28 and 7.72 (AA′XX′, J AX ) 8.6, 4H), 7.29 (s, 8H), 7.34 (dd,
J ) 7.9, 7.5, 2H), 7.45 (ddd, J ) 7.5, 1.5, 1.2, 2H), 7.53 (t, J )
1.5, 2H), 7.56 and 7.60 (AA′XX′, J AX ) 9.0, 4H), 7.88 (d, J )
1.5, 2H, H-benzenetriyl), 7.93 and 8.24 (AA′XX′, J AX ) 8.2, 8H),
7.97 (t, J ) 1.5, 1H, H-benzenetriyl), 7.97 and 8.28 (AA′XX′,
J AX ) 8.2, 8H), 8.80 and 8.90 (2 × d, J ) 4.6, 8H), 8.82 and
8.92 (2 × d, J ) 4.9, 8H); ES+-MS (in CHCl3/MeOH/HCOOH)
1101.6 ([M - Zn + 3H]2+), 1070.3 ([M - 2Zn + 6H]2+) (calcd
average mass for C144H101IN8S2Zn2 2265.22).
Dip or p h yr in 16b. To a solution of 16a (36.5 mg, 23.5
µmol) in 10 mL of toluene/i-PrOH (1:1) was added solid KOH
(11 mg), and the mixture was heated under reflux for 2 h. After
cooling, the remaining KOH was filtered off and the solvent
was evaporated. The crude product was purified by CC
(CHCl3/hexane 3:2) to yield 31.4 mg (89%) of 16b: UV/vis (CH2-
Cl2) 290 (4.79), 420 (5.86), 532 (4.36), 548 (4.45), 588 (3.78);
1H NMR (500.13 MHz) δ 3.20 (s, 1H), 7.65-7.72 (m, 9H), 7.73-
7.80 (m, 9H), 7.79 (t, J ) 1.6, 1H, H-benzenetriyl between
NiTPP and acetylene), 7.81 (t, J ) 1.6, 1H, H-benzenetriyl
between ZnTPP and acetylene), 7.88 and 8.04 (AA′XX′, J AX
)
8.4, 4H), 7.94 (t, J ) 1.6, 1H, H-benzenetriyl between NiTPP
and ZnTPP), 7.96 and 8.25 (AA′XX′, J AX ) 8.3, 4H), 8.00-8.03
(m, 6H), 8.21-8.24 (m, 6H), 8.75 (s, 4H), 8.76 and 8.78 (2 × d,
J ) 4.9, 4H), 8.96 (s, 4H), 8.97 and 8.99 (2 × d, J ) 4.7, 4H);
FAB-MS 1495.4 (calcd average mass for
1495.69).
C100H58N8NiZn
Tr ip or p h yr in 17a was obtained in 82% yield (23.8 mg),
after purification by two successive CC (CHCl3/hexane 1:1 then
3:2), reacting 16b (20.6 mg, 13.8 µmol) with 9a (13.4 mg, 18.1
µmol) in the presence of Pd(PPh3)4 (3.2 mg, 2.8 µmol), in 8 mL
of DMF/Et3N, as described for 10a : UV/vis (CH2Cl2) 292 (5.04),
420 (6.09), 520 (4.58), 548 (4.62), 590 (4.13), 650 (3.84); UV/
vis (benzene) 292 (4.97), 424 (6.06), 520 (4.55), 550 (4.61), 590
1
(4.08), 648 (3.52); EMS (benzene) λem 603, 655, 719; H NMR
(500.13 MHz) δ -2.75 (s, 2H), 7.65-7.73 (m, 9H), 7.73-7.81
(m, 18H), 7.94 and 8.07 (AA′XX′, J AX ) 8.2, 4H), 8.00 and 8.28
(AA′XX′, J AX ) 8.3, 4H), 8.00 and 8.28 (AA′XX′, J AX ) 8.3, 4H),
7.99-8.04 (m, 3H, H-benzenetriyl), 8.01-8.04 (m, 6H), 8.21-
8.25 (m, 12H), 8.76 (s, 4H), 8.79 (s, 4H), 8.86 (s, 4H), 8.90 (s,
4H), 8.96 (s, 4H), 9.00 and 9.01 (2 × d, J ) 4.7, 4H); FAB-MS
2108.0 (calcd average mass for C144H86N12NiZn 2108.45).
Tr ip or p h yr in 17b. Meth od A. To a solution of 17a (16.0
mg, 7.6 µmol) in CHCl3/MeOH (9:1) was added copper acetate
monohydrate (9.1 mg, 45.6 µmol), and the mixture was stirred
at 20 °C for 15 min. Thereafter, the mixture was washed with
water and dried (Na2SO4), and the solvent was evaporated.
The residue was purified by CC (CHCl3/hexane 3:2) to yield
15.5 mg (94%) of 17b. Meth od B. 17b was obtained in 62%
yield (6.7 mg), after purification by CC (CHCl3/hexane: gradi-
ent from 2:3 to 3:2), reacting 16b (7.5 mg, 5.0 µmol) with [5-(4-
iodophenyl)-10,15,20-triphenylporphinato(2-)]copper27 (5.2 mg,
6.5 µmol) in the presence of Pd(PPh3)4 (1.5 mg, 1.3 µmol), in 3
mL of DMF/Et3N, as described for 10a : UV/vis (CH2Cl2) 296
(4.71), 418 (5.98), 540 (4.69); UV/vis (benzene) 294 (5.05), 420
(5.99), 542 (4.72); EMS (benzene) λem 602, 649; 1H NMR (500.13
MHz) δ 7.67-7.70 (m, 9H), 7.72-7.80 (m, 9H), 7.92 and 8.07
(AA′XX′, J AX ) 7.8, 4H), 7.96-8.04 (m, 3H, H-benzenetriyl),
8.00 and 8.27 (AA′XX′, J AX ) 7.0, 4H), 8.01-8.03 (m, 6H),
8.22-8.24 (m, 6H), 8.75 (s, 4H), 8.79 (s, 4H), 8.96 (s, 4H), 8.99
Den d r im er ic h exa p or p h yr in 19 was obtained in 28%
yield (4.0 mg), as described for 8e, reacting 18c (20.2 mg, 9.0
µmol) with 1c (0.32 mg, 2.13 µmol) in the presence of Pd2dba3
(0.76 mg, 0.83 µmol) and AsPh3 (2.04 mg, 6.66 µmol), in 2.4
mL of DMF/Et3N at 30 °C after 5 h reaction time and
purification by two successive CC (CHCl3/hexane: gradient
from 3:2 to 9:1): UV/vis (CHCl3) 264 (5.37), 298 (5.44), 336
1
(5.41), 426 (6.30), 552 (5.01), 584 (4.61), 592 (4.61); H NMR

5580 J . Org. Chem., Vol. 63, No. 16, 1998
Mongin et al.
(500.13 MHz) δ 1.84 (s, 72H, o-CH3 mesityl), 2.55 (s, 18H,
SMe), 2.64 (s, 36H, p-CH3 mesityl), 7.26 (m, 6H, H-4 meth-
ylthiophenyl), 7.30 (s, 24H, H-mesityl), 7.34 (dd, J ) 8.2, 7.6,
6H, H-5 methylthiophenyl), 7.45 (dt, J ) 7.6, 6H, H-6 meth-
ylthiophenyl), 7.53 (m, 6H, H-2 methylthiophenyl), 7.55 and
7.57 (AA′BB′, 12H, H-phenylene on central benzenetriyl), 7.59
and 7.62 (AA′BB′, J AB ) 7.8, 12H, H-phenylene), 7.70 (s, 3H,
H-central benzenetriyl), 7.89 (d, J ) 1.6, 6H, H-benzenetriyl),
7.93 and 8.25 (AA′XX′, J AX ) 8.2, 24H, H-outside phenylene
on porphine), 7.97 (t, J ) 1.6, 3H, H-benzenetriyl), 7.98 and
8.29 (AA′XX′, J AX ) 8.0, 24H, H-inside phenylene on porphine),
8.81 and 8.90 (2 × d, J ) 4.7, 24H, outside â-H on porphine),
8.82 and 8.93 (2 × d, J ) 4.7, 24H, inside â-H on porphine);
ES+-MS (in CHCl3/MeOH/HCOOH) m/z 1546.4 ([M - 6Zn +
16H]4+), 1237.4 ([M - 6Zn + 17H]5+), 1031.4 ([M - 6Zn +
18H]6+) (calcd average mass for C444H306N24S6Zn6 6562.10).
Atomic absorption calcd: Zn, 5.98. Found: Zn, 5.88.
the Fondation du Fonds de la Recherche de l’Universite´
de Fribourg and to the Rector of the University for
additional financial help. Atomic absorption analyses
were performed by M. Piccand (Institut de Chimie
inorganique et analytique de l’Universite´ de Fribourg).
NMR spectra on the Bruker Avance DRX 500 instru-
ment were performed by F. Fehr and mass spectra by
F. Nydegger and I. Mu¨ller. F. Nydegger’s contribution
to the development of unprecedented procedures of
sample preparation for the measurement of ES+-mass
spectra with a Bruker APEX II FT/ICR mass spectrom-
eter is gratefully acknowledged.
Su p p or tin g In for m a tion Ava ila ble: Copies of NMR
spectra (58 pages). This material is contained in libraries on
microfiche, immediately follows this article in the microfilm
version of the journal, and can be ordered from the ACS; see
any current masthead page for ordering information.
Ack n ow led gm en t. This work has been supported
in part by the Swiss National Science Foundation
(Project No. 21-49521.96). We are greatly indebted to
J O980846+