Porphyrin architectures tailored for studies of molecular information storage

Article abstract of DOI:10.1021/jo0498260

A molecular approach to information storage employs redox-active molecules tethered to an electroactive surface. Zinc porphyrins tethered to Au(111) or Si(100) provide a benchmark for studies of information storage. Three sets of porphyrins have been synt

Full text of DOI:10.1021/jo0498260

P or p h yr in Ar ch itectu r es Ta ilor ed for Stu d ies of Molecu la r
In for m a tion Stor a ge
‡
‡
‡
‡
Carole M. Carcel, J oydev K. Laha, Robert S. Loewe, Patchanita Thamyongkit,
‡
,§
,†
,‡
Karl-Heinz Schweikart, Veena Misra,* David F. Bocian,* and J onathan S. Lindsey*
Department of Electrical and Computer Engineering, North Carolina State University,
Raleigh, North Carolina 27695, Department of Chemistry, University of California,
Riverside, California 92521-0403, and Department of Chemistry, North Carolina State University,
Raleigh, North Carolina 27695-8204
vmisra@eos.ncsu.edu; david.bocian@ucr.edu; jlindsey@ncsu.edu
Received J anuary 29, 2004
A molecular approach to information storage employs redox-active molecules tethered to an
electroactive surface. Zinc porphyrins tethered to Au(111) or Si(100) provide a benchmark for studies
of information storage. Three sets of porphyrins have been synthesized for studies of the interplay
of molecular design and charge-storage properties: (1) A set of porphyrins is described for probing
the effect of surface attachment atom on electron-transfer kinetics. Each porphyrin bears a meso-
CH X group for surface attachment where X ) OH, SAc, or SeAc. (2) A set of porphyrins is described
2
for studying the effect of surface-charge density in monolayers. Each porphyrin bears a benzyl
alcohol for surface attachment and three nonlinking meso substituents of a controlled degree of
bulkiness. (3) A set of porphyrins is described that enables investigation of on-chip patterning of
the electrolyte. Each porphyrin bears a formyl group distal to the surface attachment group for
subsequent derivatization with a molecular entity that comprises the electrolyte. Taken together,
this collection of molecules enables a variety of studies to elucidate design issues in molecular-
based information storage.
In tr od u ction
pared to date have been employed to investigate the
effects of tether structure
on charge-storage properties and surface packing pat-
storage of multiple bits,4
-9,16
We have described an approach for information storage
wherein molecules attached to an electroactive surface
serve as the active medium. In this approach, information
is stored in the discrete oxidation states of molecules. The
ability to store charge in the surface-bound molecules
allows the molecular medium to mimic the function of a
semiconductor capacitor such as that found in a dynamic
random access memory cell (which is comprised of a
(4) Gryko, D. T.; Zhao, F.; Yasseri, A. A.; Roth, K. M.; Bocian, D. F.;
Kuhr, W. G.; Lindsey, J . S. J . Org. Chem. 2000, 65, 7356-7362.
(5) Clausen, C.; Gryko, D. T.; Dabke, R. B.; Dontha, N.; Bocian, D.
F.; Kuhr, W. G.; Lindsey, J . S. J . Org. Chem. 2000, 65, 7363-7370.
6) Clausen, C.; Gryko, D. T.; Yasseri, A. A.; Diers, J . R.; Bocian, D.
F.; Kuhr, W. G.; Lindsey, J . S. J . Org. Chem. 2000, 65, 7371-7378.
7) Li, J .; Gryko, D.; Dabke, R. B.; Diers, J . R.; Bocian, D. F.; Kuhr,
W. G.; Lindsey, J . S. J . Org. Chem. 2000, 65, 7379-7390.
8) Gryko, D.; Li, J .; Diers, J . R.; Roth, K. M.; Bocian, D. F.; Kuhr,
W. G.; Lindsey, J . S. J . Mater. Chem. 2001, 11, 1162-1180.
9) Schweikart, K.-H.; Malinovskii, V. L.; Diers, J . R.; Yasseri, A.
A.; Bocian, D. F.; Kuhr, W. G.; Lindsey, J . S. J . Mater. Chem. 2002,
2, 808-828.
10) Li, Q.; Mathur, G.; Homsi, M.; Surthi, S.; Misra, V.; Malinovskii,
(
(
1
transistor-capacitor pair). A system of particular inter-
(
est is a hybrid architecture composed of information-
storage molecules located in the memory cells of tradi-
tional, photolithographically constructed memory chips.
The generic design of the information-storage mol-
ecules includes a redox-active unit and a covalently
attached tether; the tether is composed of a linker bearing
a terminal functional group for surface attachment.
Within this generic design, we have prepared a wide
variety of molecular architectures as candidates for
(
1
(
V.; Schweikart, K.-H.; Yu, L.; Lindsey, J . S.; Liu, Z.; Dabke, R. B.;
Yasseri, A.; Bocian, D. F.; Kuhr, W. G. Appl. Phys. Lett. 2002, 81,
1
494-1496.
(
11) Roth, K. M.; Gryko, D. T.; Clausen, C.; Li, J .; Lindsey, J . S.;
Kuhr, W. G.; Bocian, D. F. J . Phys. Chem. B 2002, 106, 8639-8648.
(12) Roth, K. M.; Yasseri, A. A.; Liu, Z.; Dabke, R. R.; Malinovskii,
V.; Schweikart, K.-H.; Yu, L.; Tiznado, H.; Zaera, F.; Lindsey, J . S.;
Kuhr, W. G.; Bocian, D. F. J . Am. Chem. Soc. 2003, 125, 505-517.
2
-21
information-storage applications.
The molecules pre-
(13) Roth, K. M.; Liu, Z.; Gryko, D. T.; Clausen, C.; Lindsey, J . S.;
‡
Department of Chemistry, North Carolina State University.
Department of Electrical and Computer Engineering, North
Bocian, D. F.; Kuhr, W. G. Molecules as Components of Electronic
Devices; ACS Symp. Ser. No. 844; American Chemical Society: Wash-
ington, DC, 2003; pp 51-61.
§
Carolina State University.
†
Department of Chemistry, University of California.
(14) Li, Q.; Surthi, S.; Mathur, G.; Gowda, S.; Sorenson, T. A.;
Tenent, R. C.; Kuhr, W. G.; Tamaru, S.-I.; Lindsey, J . S.; Liu, Z.;
Bocian, D. F.; Misra, V. Appl. Phys. Lett. 2003, 83, 198-200.
(15) Liu, Z.; Yasseri, A. A.; Lindsey, J . S.; Bocian, D. F. Science 2003,
302, 1543-1545.
(1) Roth, K. M.; Dontha, N.; Dabke, R. B.; Gryko, D. T.; Clausen,
C.; Lindsey, J . S.; Bocian, D. F.; Kuhr, W. G. J . Vac. Sci. Technol. B.
2
000, 18, 2359-2364.
2) Gryko, D. T.; Clausen, P. C.; Lindsey, J . S. J . Org. Chem. 1999,
4, 8635-8647.
3) Gryko, D. T.; Clausen, C.; Roth, K. M.; Dontha, N.; Bocian, D.
F.; Kuhr, W. G.; Lindsey, J . S. J . Org. Chem. 2000, 65, 7345-7355.
(
6
(16) Li, Q.; Mathur, G.; Gowda, S.; Surthi, S.; Zhao, Q.; Yu, L.;
Lindsey, J . S.; Bocian, D. F.; Misra, V. Adv. Mater. 2004, 16, 133-
137.
(
1
0.1021/jo0498260 CCC: $27.50 © 2004 American Chemical Society
Published on Web 09/02/2004
J . Org. Chem. 2004, 69, 6739-6750
6739

Carcel et al.
terns,13,19,20 effect of molecular packing densities on
CHART 1
1
1,12
charge-storage properties,
stability toward processing
and operation (i.e., repeated redox cycling),15 and incor-
poration of surface attachment groups for binding to
Au,1
TiO
-9,11,13
Si or Ge,
10,12,17,21
2
or metal oxides (e.g., SiO ,
).14,18,19
2
A number of issues remain to be addressed concerning
the interplay of molecular design and charge-storage
properties for use in memory devices. The motivation for
the work described herein centers on three particular
issues.
We have principally used thiols for attachment to Au
and alcohols for attachment to Si (and Ge) surfaces. It is
of interest to understand how the type of atom that is
used for surface attachment affects the electron-transfer
properties. In particular, theoretical studies by Ratner
and co-workers have indicated that the conductivity
through a molecule spanning two Au electrodes and
attached via a chalcogenide monotonically increases down
the group O < S < Se.22 This hypothesis has not yet been
tested.
We have observed that the electron-transfer rates
increase as the packing density in a self-assembled
monolayer (SAM) decreases.1
1,12
Such studies were per-
formed by successive dilution of the SAMs. A factor of
0 difference in rate could be obtained for a given redox-
1
active molecule. Such an approach may enable metal
deposition directly on the electrolyte/molecule layer given
that a liquid or gel electrolyte is no longer employed.
The ultimate design of molecules for use in informa-
tion-storage applications requires consideration of all of
the issues raised above. In this paper, we describe the
synthesis of a number of porphyrins that can be used to
address each issue. First, a set of porphyrins is described
for probing the effect of surface attachment atom on
active unit by control over the packing density. It is of
interest to determine whether packing densities could be
more effectively controlled by building in the desired level
of steric bulk in the molecules employed to form the SAM.
Our present approach toward chip fabrication entails
formation of the monolayer on a chip containing photo-
lithographically defined memory cells, formation of a top
contact to the molecules via an electrolyte drop (e.g.,
4 6 2 2 4 6
Bu NPF in CH Cl ) or a gel electrolyte (e.g., Bu NPF
2
electron-transfer kinetics. Each porphyrin bears a -CH X
in propylene carbonate), followed by solvent evaporation
and deposition of the counter electrode. While this
approach enables studies of the information-storage
properties of the molecules, the methods for electrolyte
deposition are not very amenable to device fabrication.
In fabricating a hybrid chip containing molecular materi-
als, it is essential to be able to (i) locate the electrolyte
only in those regions of the chip where the molecules are
located, (ii) control the thickness of the electrolyte layer,
and (iii) introduce the counter electrode without creating
shorts across the electrolyte/molecule region. At present,
little control can be exercised over such “patterning of
the electrolyte”, which directly affects the methods
employed for introducing the counter electrode. Conse-
quently, it is of interest to explore molecular designs
wherein the electrolyte is an integral part of the redox-
group for surface attachment, where X ) OH, SAc, or
SeAc. Second, a series of porphyrins is described for
probing the effect of surface-charge density in mono-
layers. Each porphyrin bears a benzyl alcohol for surface
attachment and three nonlinking meso substituents of a
controlled degree of bulkiness. Third, a set of porphyrins
is described that can be employed in studies of electrolyte
patterning. Each porphyrin bears a formyl group distal
to the tether for subsequent derivatization with a mo-
lecular entity that comprises the electrolyte. This collec-
tion of molecules enables a variety of studies to elucidate
design issues in molecular-based information storage.
Examination of the charge-storage properties of the
various molecules and the suitability of different designs
for use in hybrid molecule-silicon memory chips is
beyond the scope of this paper and will be described
elsewhere.
(17) Balakumar, A.; Lysenko, A. B.; Carcel, C.; Malinovskii, V. L.;
Gryko, D. T.; Schweikart, K.-H.; Loewe, R. S.; Yasseri, A. A.; Liu, Z.;
Bocian, D. F.; Lindsey, J . S. J . Org. Chem. 2004, 69, 1435-1443.
Resu lts a n d Discu ssion
(
18) Muthukumaran, K.; Loewe, R. S.; Ambroise, A.; Tamaru, S.-I.;
Li, Q.; Mathur, G.; Bocian, D. F.; Misra, V.; Lindsey, J . S. J . Org. Chem.
004, 69, 1444-1452.
19) Loewe, R. S.; Ambroise, A.; Muthukumaran, K.; Padmaja, K.;
I. P or p h yr in s for In vest iga t ion of E ffect s of
Su r fa ce-Atta ch m en t Gr ou p s on Electr on -Tr a n sfer
Ra tes. Ra tion a le: We previously prepared a set of
porphyrins to examine the effects of the surface attach-
ment group on the electron-transfer properties of the
porphyrin in a SAM.17 The porphyrins (Zn -1a -c, Chart
2
(
Lysenko, A. B.; Mathur, G.; Li, Q.; Bocian, D. F.; Misra, V.; Lindsey,
J . S. J . Org. Chem. 2004, 69, 1453-1460.
(20) Wei, L.; Padmaja, K.; Youngblood, W. J .; Lysenko, A. B.;
Lindsey, J . S.; Bocian, D. F. J . Org. Chem. 2004, 69, 1461-1469.
(21) Liu, Z.; Yasseri, A. A.; Loewe, R. S.; Lysenko, A. B.; Malinovskii,
V. L.; Zhao, Q.; Surthi, S.; Li, Q.; Misra, V.; Lindsey, J . S.; Bocian, D.
1
) were attached to the surface via a benzyl-X group
F. J . Org. Chem. 2004, 69, 5568-5577.
where X was an oxygen, sulfur, or selenium atom. (The
(22) Yaliraki, S. N.; Kemp, M.; Ratner, M. A. J . Am. Chem. Soc.
1
999, 121, 3428-3434.
S-acetyl or Se-acetyl protecting group undergoes cleavage
6
740 J . Org. Chem., Vol. 69, No. 20, 2004

A Molecular Approach to Information Storage
upon exposure to the Si surface, resulting in attachment
SCHEME 1
1
7
via the S or Se atom. ) We found that the electron-
transfer properties of the porphyrins were similar to one
another. We considered the absence of any observable
difference in the electron-transfer properties with O/S/
Se groups might be attributed to the presence of the
intervening phenyl unit, which limits the electron-
transfer rate. We have now redesigned the molecules to
contain only a -CH
2
X group (Zn -2a -c).
A variety of porphyrins bearing one or more meso-
2
3-25
hydroxymethyl groups have been prepared.
The
synthetic approach generally employed entails Vilsmeier
formylation of an acid-stable metalloporphyrin (e.g., Ni,
Cu) followed by (optional: demetalation and) reduction
of the formyl group to give the hydroxymethyl group.
Most porphyrins contained multiple â substituents.
Indeed, the only example of a porphyrin bearing one free
meso site, three nonlinking meso substituents, and no â
substituents was prepared by a statistical process.24 To
our knowledge, no porphyrins with a directly attached
S-acetylthiomethyl or Se-acetylselenomethyl group have
been prepared.
with excess pyrrole (100 equiv) in the presence of 0.1
equiv of InCl at room temperature gave the desired
3
dipyrromethane 4a as well as the N-confused dipyrro-
methane (upon GC analysis after 24 h). Workup of this
mixture gave 4a in 29% yield. The same reaction at 60
°
C for 2 h afforded dipyrromethane 4a as a white solid
in 61% yield and the N-confused dipyrromethane in 15%
yield (Scheme 2). The reaction of acetal 3b with excess
Syn th esis: The synthesis of porphyrins bearing dis-
tinct patterns of meso substituents can be achieved by
reaction of a dipyrromethane and a dipyrromethane-
dicarbinol.26 Accordingly, we have investigated an ap-
pyrrole (100 equiv) in the presence of 0.3 equiv of InCl
at room temperature resulted in 50% starting material
after 24 h. Refinement of the conditions [InCl (0.3 equiv),
pyrrole (100 equiv), 60 °C, 10 h] afforded dipyrromethane
b as an oil in 48% yield. Compound 4b was found to be
99% pure by GC analysis, though the elemental analy-
3
3
2
proach wherein the -CH X group is incorporated at the
meso position of the dipyrromethane. The synthesis of
the dipyrromethanes requires a hydroxy, S-acetylthio, or
Se-acetylseleno group at the R-position of acetaldehyde.
The diethyl acetal of R-hydroxyacetaldehyde (3a ) is
commercially available. Treatment of commercially avail-
able R-bromoacetaldehyde diethylacetal with KSAc af-
forded acetal 3b in 79% yield (Scheme 1). The requisite
KSeAc27 was prepared from diacetylselenide and re-
acted directly with R-bromoacetaldehyde diethylacetal in
DMF at room temperature, affording Se-acetylseleno-
acetaldehyde diethylacetal 3c in crude form. The latter
was used without further purification in the synthesis
of the dipyrromethane.
4
>
sis of 4b (and the precursor 3b) deviated slightly from
the expected values. The analogous condensation of crude
3
c for 12 h followed by chromatography afforded di-
pyrromethane 4c as an oil (8% yield from diacetyl-
selenide).
28
The synthesis of free base porphyrin 2a was pursued
by condensation of dipyrromethane 4a with dipyrro-
30
methane-dicarbinol 5-diol at room temperature (Scheme
2
). The synthesis was investigated with use of TFA in
26
CH , Sc(OTf)
3
CN or a Lewis acid catalyst [InCl
3
3
, Yb-
31
(OTf) , or Dy(OTf) ] in CH Cl . With TFA catalysis, the
3 3 2 2
The one-flask reaction of an aldehyde with excess
pyrrole affords the dipyrromethane. We recently devel-
oped refined conditions that employ a mild Lewis acid
as catalyst and refined workup conditions to give the
dipyrromethane with minimal or no chromatography.29
Thus, condensation of glycolaldehyde diethylacetal (3a )
maximum spectroscopic yield reached 6%. The Lewis
acids gave yields of 0%, 10%, 12%, and 8%, respectively.
A scaled-up synthesis with Yb(OTf) afforded 2a in 17%
3
isolated yield. Analysis of the crude reaction mixture by
32
laser-desorption mass spectrometry (LD-MS) did not
reveal the formation of any porphyrin species derived
from acidolysis of dipyrromethane species (i.e., scram-
bling). The similar reaction of 5-diol with dipyrromethane
(
23) (a) Smith, K. M.; Bisset, G. M. F. J . Org. Chem. 1979, 44, 2077-
2
081. (b) Ogoshi, H.; Saita, K.; Sakurai, K.-I.; Watanabe, T.; Toi, H.;
4
3
b or 4c under Yb(OTf) catalysis afforded free-base
Aoyama, Y. Tetrahedron Lett. 1986, 27, 6365-6368. (c) Ponomarev,
G. V.; Borovkov, V. V.; Shul’ga, A. M.; Sakata, Y. J . Chem. Soc., Chem.
Commun. 1994, 1927-1928. (d) Higuchi, H.; Shimizu, K.; Ojima, J .;
Sugiura, K.-I.; Sakata, Y. Tetrahedron Lett. 1995, 36, 5359-5362. (e)
Torpey, J . W.; Ortiz de Montellano, P. R. J . Org. Chem. 1995, 60, 2195-
porphyrin 2b or 2c in 29% or 18% yield, respectively. In
each case, LD-MS did not reveal any scrambling. Por-
phyrins 2a -c were treated separately with Zn(OAc)
O to afford Zn -2a -c.
II. P or p h yr in s w ith Con tr olled F a cia l En cu m -
2
‚
2
H
2
2
199. (f) Higuchi, H.; Shimizu, K.; Takeuchi, M.; Ojima, J .; Sugiura,
K.-I.; Sakata, Y. Bull. Chem Soc. J pn. 1997, 70, 1923-1933. (g)
Balaban, T. S.; Bhise, A. D.; Fischer, M.; Linke-Schaetzel, M.; Roussel,
C.; Vanthuyne, N. Angew. Chem., Int. Ed. 2003, 42, 2140-2144.
br a n ce for Stu d ies of Su r fa ce Ch a r ge Den sity on
(24) Tkachenko, N. V.; Lemmetyinen, H.; Sonoda, J .; Ohkubo, K.;
Sato, T.; Imahori, H.; Fukuzumi, S. J . Phys. Chem. A 2003, 107, 8834-
844.
25) Xu, Y.; J aquinod, L.; Wickramasinghe, A.; Smith, K. M.
Tetrahedron Lett. 2003, 44, 7753-7756.
26) Rao, P. D.; Dhanalekshmi, S.; Littler, B. J .; Lindsey, J . S. J .
Org. Chem. 2000, 65, 7323- 7344.
27) Kageyama, H.; Takagi, K.; Murai, T.; Kato, S. Z. Naturforsch.
989, 44b, 1519-1523.
28) Koketsu, M.; Nada, F.; Hiramatsu, S.; Ishihara, H. J . Chem.
Soc., Perkin Trans. 1 2002, 737-740.
(29) Laha, J . K.; Dhanalekshmi, S.; Taniguchi, M.; Ambroise, A.;
Lindsey, J . S. Org. Proc. Res. Dev. 2003, 7, 799-812.
(30) Tamaru, S.-I.; Yu, L.; Youngblood, W. J .; Muthukumaran, K.;
Taniguchi, M.; Lindsey, J . S. J . Org. Chem. 2004, 69, 765-777.
(31) Geier, G. R., III; Callinan, J . B.; Rao, P. D.; Lindsey, J . S. J .
Porphyrins Phthalocyanines 2001, 5, 810-823.
(32) (a) Srinivasan, N.; Haney, C. A.; Lindsey, J . S.; Zhang, W.;
Chait, B. T. J . Porphyrins Phthalocyanines 1999, 3, 283-291. (b)
Fenyo, D.; Chait, B. T.; J ohnson, T. E.; Lindsey, J . S. J . Porphyrins
Phthalocyanines 1997, 1, 93-99.
8
(
(
(
1
(
J . Org. Chem, Vol. 69, No. 20, 2004 6741

Carcel et al.
SCHEME 2
CHART 2
upon reaction with dipyrromethane 1036,37 under TFA
catalysis followed by oxidation with DDQ gave porphyrin
1
1 in 16% yield. Porphyrin 11 also has been prepared
previously via statistical (mixed-aldehyde) condensa-
tions.3
Zn -11, which was reduced with LiAlH
quantitative yield (Scheme 3). The direct conversion of
1 to Zn -7 (via Zn -11 but without isolation) was achieved
in 95% overall yield.
2) Sw a llow ta il P or p h yr in s. We recently prepared
4,38
Treatment of 11 with Zn(OAc)
to give Zn -7 in
2
2
‚2H O gave
4
1
(
a series of porphyrin building blocks that incorporate
tridec-7-yl (i.e., “swallowtail”) substituents at the meso
positions.39 The hexyl chains project above and below the
plane of the porphyrin macrocycle, with the C-H bond
of the branching carbon (C7) lying in the plane of the
macrocycle. Porphyrin building blocks with 1-4 swal-
lowtail substituents were prepared; however, it was
necessary to employ statistical approaches to gain access
to porphyrins bearing three swallowtail substituents
owing to the inability to reduce 1,9-diacyldipyrromethanes
bearing swallowtail groups at the acyl positions. The
statistical approach we employed herein to prepare Zn -8
is shown in Scheme 4.
Ch a r ge-Stor a ge P r op er ties. Ra tion a le: We sought to
prepare a series of porphyrin-benzyl alcohols wherein
the size of the nonlinking groups could be used to control
the distance of separation of the porphyrins in self-
assembled monolayers on the silicon surface. We previ-
ously have prepared porphyrin-benzyl alcohols bearing
mesityl (Zn -1a ) or pentyl (Zn -6) groups at the three
nonlinking meso positions. We now describe the synthesis
of zinc porphyrins that bear p-tolyl (Zn -7) or swallowtail
The condensation of aldehyde 12,40 dipyrromethane
13,39 and methyl 4-formylbenzoate in a stoichiometric
(Zn -8) groups at the nonlinking meso positions (Chart
2
). Several different synthetic routes have been pursued
(
36) (a) Br u¨ ckner, C.; Zhang, Y.; Rettig, S. J .; Dolphin, D. Inorg.
to prepare the porphyrins.
Chim. Acta 1997, 263, 279-286. (b) Ka, J .-W.; Lee, C.-H. Tetrahedron
Lett. 2000, 41, 4609-4613. (c) Luo, C.; Guldi, D. M.; Imahori, H.;
Tamaki, K.; Sakata, Y. J . Am. Chem. Soc. 2000, 122, 6535-6551.
Syn th esis: (1) p-Tolyl P or p h yr in s. The target zinc
porphyrin (Zn -7) bears one p-benzyl alcohol and three
meso p-tolyl substituents. The corresponding free base
porphyrin (7) has been prepared by statistical routes.3
A rational approach was pursued by reduction of 1,9-
diacyldipyrromethane 935 to give the dicarbinol, which
(37) Balaban, T. S.; Eichh o¨ fer, A.; Lehn, J .-M. Eur. J . Org. Chem.
2
000, 4047-4057.
3,34
(
38) (a) Anton, J . A.; Loach, P. A. J . Heterocycl. Chem. 1975, 573-
576. (b) Williamson, D. A.; Bowler, B. E. Tetrahedron 1996, 52, 12357-
12372.
(39) Thamyongkit, P.; Speckbacher, M.; Diers, J . R.; Kee, H. L.;
Kirmaier, C.; Holten, D.; Bocian, D. F.; Lindsey, J . S. J . Org. Chem.
2004, 69, 3700-3710.
(40) Kato, M.; Komoda, K.; Namera, A.; Sakai, Y.; Okada, S.;
Yamada, A.; Yokoyama, K.; Migita, E.; Minobe, Y.; Tani, T. Chem.
Pharm. Bull. 1997, 45, 1767-1776.
(
33) Takahashi, Y.; Guillet, J . E.; Winnik, M. A. Can. J . Chem. 1989,
6
7, 411-416.
(
(
34) Hombrecher, H. K.; Ohm, S. Tetrahedron 1993, 49, 2447-2456.
35) Gryko, D.; Lindsey, J . S. J . Org. Chem. 2000, 65, 2249-2252.
6
742 J . Org. Chem., Vol. 69, No. 20, 2004

A Molecular Approach to Information Storage
SCHEME 3
SCHEME 4
Metalation of porphyrin 14 with Zn(OAc)
2
2
‚2H O af-
forded Zn -14 in 85% yield. Treatment of Zn -14 with
LiAlH in THF at room temperature for 2 h gave
4
porphyrin-alcohol Zn -8 in 80% yield.
III. P or p h yr in s for On -Ch ip P a t t er n in g of t h e
Electr olyte. Ra tion a le: An approach toward patterning
the electrolyte is to attach an entity having a fixed charge
ratio of 1:2:1 afforded the three expected porphyrins. The
diester-porphyrin was the dominant porphyrin product
and porphyrin 14 was isolated in 2% yield. Statistical
considerations alone indicate the desired porphyrin 14
should be formed in maximum amounts when the ratio
of reactants is equal to the stoichiometry required for
formation of 14, but the different reactivity of the various
components can skew the actual product ratio. Upon
increasing the amount of aldehyde 12 to a reactant ratio
of 2:2:1, 14 was obtained in 8% yield (Scheme 4). We also
investigated two other statistical routes. The condensa-
tion of swallowtail dipyrromethane 13, aldehyde 12, and
(i.e., the electrolyte) to the charge-storage molecule. In
this manner, the electrolyte is confined to the same
locations as the charge-storage molecules, and the use
of a liquid electrolyte is avoided altogether. The charged
group can entail a fixed cation and mobile anion, a fixed
anion and a mobile cation, or multiple charged groups of
one or both types.
The use of a bipartite molecule composed of an elec-
trolyte and charge-storage moiety leads to a design
wherein the bipartite structure is assembled on a memory
chip in a two-step process. In step one, the charge-storage
molecule is attached to the electroactive surface of
memory storage cells in the chip. In step two, the
electrolyte unit is attached to the charge-storage mol-
ecules. The two-step approach for electrolyte attachment
requires conditions such that (i) the surface, surface
5
-(4-carbomethoxyphenyl)dipyrromethane (10) in 1:2:1
ratio gave 14 in <1% yield, and the condensation of
pyrrole, 12, and methyl 4-formylbenzoate in 4:3:1 ratio
gave 14 in 4% yield. No substantial improvements were
obtained upon varying the ratios of the reactants.
J . Org. Chem, Vol. 69, No. 20, 2004 6743

Carcel et al.
CHART 3
SCHEME 5
attachment linkage, redox-active molecule, and any other
components on the chip are unaffected by the electrolyte
attachment procedure and (ii) reaction occurs essentially
quantitatively. Reactions that meet these criteria typi-
cally occur under mild conditions. Among the possible
reactions, imine formation by condensation of an alde-
hyde (attached to the information-storage molecule) and
a hydrazide (bearing the charged group) is particularly
attractive. Indeed, hydrazide reagents bearing charged
pyridinium
or
tri-
methylammonium groups (Girard’s reagents P or T) have
The synthesis of target molecule Zn -15 is shown in
4
1
been used extensively for gentle derivatization of alde-
Scheme 5. The condensation of 5-mesityldipyrromethane
4
2
hydes with rich functionality such as chlorophyll b,
9,45
(
19)2
and methyl 4-formylbenzoate was carried out
carotenoids,43 and other complex molecules.44
4
6
under the standard conditions for forming trans-A
porphyrins from sterically hindered dipyrromethanes
17.8 mM TFA in CH Cl at room temperature). Subse-
2 2
B -
Four target molecules (Zn -15-Zn -18) were identified
that meet the molecular design criteria (Chart 3). Each
molecule incorporates a zinc porphyrin as the redox-
active molecule. The porphyrin can be attached to an
electroactive surface via a benzyl linker bearing an S or
O atom. The distal formyl or 4-formylphenyl group
provides a site for attachment of the electrolyte at a fixed
distance from the porphyrin.
(
2
2
quent oxidation with DDQ afforded the desired free base
porphyrin 20 in 25% yield. Compound 20 has been
reported with characterization data but without descrip-
47
tion of a synthetic procedure. Reduction of 20 with
excess LiAlH afforded porphyrin-diol 21 in 87% yield.
4
Treatment of 21 with 1 equiv of PCC afforded a statistical
mixture, which was readily separated chromatographi-
cally affording the desired monoaldehyde 15 in 46% yield.
A related route to a porphyrin with undecyl rather than
Syn th esis: Each target compound (Zn -15-Zn -18) is
a trans-AB C-porphyrin. Many trans-AB C-porphyrins
2 2
can be synthesized in a rational manner by reaction of a
dipyrromethane-dicarbinol and a dipyrromethane.26 How-
ever, given the presence of two mesityl groups and two
sensitive substituents (formyl and alcohol or S-acetylthio)
per porphyrin, we chose a synthesis that employs an
aldehyde + dipyrromethane reaction to construct the
porphyrin macrocycle in conjunction with one statistical
step (either during or after porphyrin formation) to
37
mesityl substituents has been described. Zinc insertion
gave the target porphyrin Zn -15.
The synthesis of porphyrin Zn -16 is shown in Scheme
. The chosen route to porphyrin Zn -16, which bears an
6
S-acetylthiomethyl functionality and a formylphenyl
group, requires protection of the formyl group during the
porphyrin-forming process. A statistical reaction of ac-
achieve the trans-AB
2
C substitution pattern.
48
etal-aldehyde 22 (available from 4-cyanobenzaldehyde
(
(
41) Wheeler, O. H. Chem. Rev. 1961, 61, 205-221.
42) (a) Wetherell, H. R.; Hendrickson, M. J . J . Org. Chem. 1959,
(45) Littler, B. J .; Miller, M. A.; Hung, C.-H.; Wagner, R. W.; O’Shea,
D. F.; Boyle, P. D.; Lindsey, J . S. J . Org. Chem. 1999, 64, 1391-1396.
(46) Littler, B. J .; Ciringh, Y.; Lindsey, J . S. J . Org. Chem. 1999,
64, 2864-2872.
(47) Liddell, P. A.; Kodis, G.; de la Garza, L.; Bahr, J . L.; Moore, A.
L.; Moore, T. A.; Gust, D. Helv. Chim. Acta 2001, 84, 2765-2783.
(48) Lindsey, J . S.; Schreiman, I. C.; Hsu, H. C.; Kearney, P. C.;
Marguerettaz, A. M. J . Org. Chem. 1987, 52, 827-836.
2
4, 710-711. (b) Kenner, G. W.; McCombie, S. W.; Smith, K. M. J .
Chem. Soc., Perkin Trans. 1 1973, 2517-2523. (c) Losev, A.; Mauzerall,
D. Photochem. Photobiol. 1983, 38, 355-361.
(
43) Kanofsky, J . R.; Sima, P. D. Photochem. Photobiol. 2001, 73,
3
49-358.
(
44) Caldwell, A. G. J . Chem. Soc. 1952, 2035-2041.
6
744 J . Org. Chem., Vol. 69, No. 20, 2004

A Molecular Approach to Information Storage
SCHEME 6
SCHEME 7
4
9
or methyl 4-formylbenzoate ), 4-(S-acetylthiomethyl)-
3
benzaldehyde (23), and 5-mesityldipyrromethane (19)
under the standard conditions for reactions of sterically
hindered dipyrromethanes46 followed by oxidation with
DDQ gave the expected mixture of three porphyrins.
Chromatographic workup yielded the desired trans-AB
porphyrin 24 in 11% yield. Hydrolysis of the acetal group
in 24 was achieved in a biphasic solution of CH Cl /TFA/
2
C
2
2
5
0
H
2
O
for 16 h to give porphyrin-aldehyde 16 in 89%
yield. Metalation with Zn(OAc)
ature gave Zn -16 in 90% yield.
2
2
‚2H O at room temper-
The synthesis of porphyrin Zn -17 can be divided
essentially in three steps: meso-formylation, bromination
of the remaining free meso position, and attachment of
the hydroxymethylphenyl group by Suzuki coupling
(
Scheme 7). Metalation of porphyrin 2551 with copper
acetate afforded the copper chelate Cu -25, which upon
Vilsmeier formylation52 gave the meso-formyl product
Cu -26 in 84% yield. It is noteworthy that monoformyla-
tion resulted even upon use of excess formylation reagent,
indicating that the remaining meso position was deacti-
vated. However, application of the standard conditions
To suppress the deactivation caused by the presence
of the meso-formyl group, Cu -26 was demetalated with
concentrated H
2 4
SO in TFA to give the free base meso-
formyl porphyrin 26 in 89% yield. [Note that analogues
for meso-bromination (1 equiv of NBS in CHCl
3
and
2
5,55
of Cu -26 (and 26) with 3,5-di-tert-butylphenyl
or
pyridine at room temperature)5
3,54
resulted in partial
phenyl56 in place of mesityl groups have been prepared.]
bromination at a â-position rather than the desired meso
site.
Porphyrin 26 was treated with neopentyl glycol in the
presence of p-TsOH‚H O in refluxing benzene to give the
2
acetal-porphyrin 27 in 90% yield. Bromination of 27
with NBS in the presence of pyridine54 gave a mixture
of the corresponding bromo-acetal-porphyrin and a small
amount (∼5%) of porphyrin 28. Treatment of the mixture
(
(
49) Nagata, T. Bull. Chem. Soc. J pn. 1991, 64, 3005-3016.
50) Lindsey, J . S.; Brown, P. A.; Siesel, D. A. Tetrahedron 1989,
4
5, 4845-4866.
(
51) Yu, L.; Muthukumaran, K.; Sazanovich, I. V.; Kirmaier, C.;
Hindin, E.; Diers, J . R.; Boyle, P. D.; Bocian, D. F.; Holten, D.; Lindsey,
J . S. Inorg. Chem. 2003, 42, 6629-6647.
(
52) J ohnson, A. W.; Oldfield, D. J . Chem. Soc. (C) 1966, 794-798.
(55) Susumu, K.; Shimidzu, T.; Tanaka, K.; Segawa, H. Tetrahedron
Lett. 1996, 37, 8399-8402.
(56) Yeung, M.; Ng, A. C. H.; Drew, M. G. B.; Vorpagel, E.; Breitung,
E. M.; McMahon, R. J .; Ng, D. K. P. J . Org. Chem. 1998, 63, 7143-
7150.
(53) Nudy, L. R.; Hutchinson, H. G.; Schieber, C.; Longo, F. R.
Tetrahedron 1984, 40, 2359-2363.
54) DiMagno, S. G.; Lin, V. S.-Y.; Therien, M. J . J . Org. Chem. 1993,
8, 5983-5993.
(
5
J . Org. Chem, Vol. 69, No. 20, 2004 6745

Carcel et al.
SCHEME 8
storage properties. The ability to readily achieve different
molecular designs through straightforward syntheses
augurs well for the systematic identification of molecules
suitable for use in hybrid information-storage constructs.
Exp er im en ta l Section
Non com m er cia l Com p ou n d s. Compounds 5, 9,35 10,36,37
3
0
4
0
39
29,45
48,49
3
51
17
1
2, 13, 19,
22,
lenide were prepared as described in the literature.
-(Hyd r oxym eth yl)-15-p h en yl-10,20-d i-p-tolylp or p h y-
23, 25, Zn -1a -c, and diacetylse-
2
8
5
3
0
r in (2a ). Following a general procedure, a sample of 5 (1.72
g, 2.50 mmol) was reduced with NaBH in dry THF/methanol
9:1) and the resulting 5-d iol was condensed with 4a (443 mg,
4
(
2
1
.50 mmol) in CH
.60 mmol) at room temperature for 4 min. DDQ (1.71 g, 7.50
2 2 3
Cl (500 mL) containing Yb(OTf) (1.00 g,
mmol) was added. The reaction mixture was concentrated and
passed over a silica column [CH Cl f CH Cl /ethyl acetate
98:2)] to afford a purple solid (260 mg, 17%): H NMR δ -2.84
br s, 2H), 2.73 (s, 6H), 6.98 (d, J ) 5.2 Hz, 2H), 7.57 (d, J )
.0 Hz, 4H), 7.75 (m, 3H), 8.08 (d, J ) 8.0 Hz, 4H), 8.19 (d, J
8.2 Hz, 2H), 8.81 (d, J ) 4.4 Hz, 2H), 8.82 (d, J ) 4.4 Hz,
H), 9.01 (d, J ) 4.4 Hz, 2H), 9.61 (d, J ) 4.4 Hz, 2H); LD-MS
obsd 598.0; FAB-MS obsd 596.2598, calcd 596.2576 (C41 O);
abs 422, 516, 552, 589, 654 nm.
Zn (II)-5-(Hydr oxym eth yl)-15-ph en yl-10,20-di-p-tolylpor -
p h yr in (Zn -2a ). Porphyrin 2a (258 mg, 0.432 mmol) was
dissolved in CHCl (50 mL) and a solution of Zn(OAc) ‚2H
474 mg, 2.16 mmol) in methanol (8 mL) was added. The
reaction mixture was stirred at room temperature for 16 h,
then concentrated and chromatographed [silica, CH Cl /ethyl
2
2
2
2
1
(
(
8
)
2
32 4
H N
λ
3
2
2
O
(
2
2
acetate (98:2)]. The product was concentrated to dryness. The
resulting solid was washed first with methanol and then with
1
hexanes, affording a purple solid (125 mg, 44%): H NMR δ
2
3
8
.74 (s, 6H), 6.37 (s, 2H), 7.56 (d, J ) 8.0 Hz, 4H), 7.72 (m,
H), 8.06 (d, J ) 8.0 Hz, 4H), 8.18 (d, J ) 8.2 Hz, 2H), 8.90-
2 2 2
with CH Cl /TFA/H O led to porphyrin 28 in 54% overall
yield. Suzuki coupling of 28 and 4-hydroxymethyl-
phenylboronic acid under conditions57 known to succeed
with porphyrin substrates gave the porphyrin (17) bear-
ing a hydroxymethylphenyl group in 78% yield upon
chromatographic workup. Metalation with zinc acetate
gave the desired target molecule Zn -17 in 88% yield.
.95 (m, 4H), 9.00 (d, J ) 4.5 Hz, 2H), 9.27 (d, J ) 4.5 Hz,
+
2H); LD-MS obsd 660.5, 643.3 [(M - OH) ]; FAB-MS obsd
658.1711, calcd 658.1713 (C41
-(S-Acetylth iom eth yl)-15-p h en yl-10,20-d i-p-tolylp or -
p h yr in (2b). As described for 2a , condensation of 5-d iol
derived from 5; 0.62 g, 0.90 mmol) and 4b (210 mg, 0.900
mmol) in CH Cl (360 mL) containing Yb(OTf) (720 mg, 1.16
30 4
H N OZn); λabs 422, 551, 589 nm.
5
(
2
2
3
The synthesis of target porphyrin Zn -18 was achieved
as shown in Scheme 8. Treatment of porphyrin 17 with
mmol) at room temperature for 4 min, oxidation with DDQ
(610 mg, 2.68 mmol), and chromatography [silica, CH Cl /ethyl
2
1
2
PBr
3
under conditions for reaction of benzyl alcohols58
acetate (19:1)] afforded a purple solid (0.17 g, 29%): H NMR
δ -2.78 (br s, 2H), 2.45 (s, 3H), 2.71 (s, 6H), 6.62 (s, 2H), 7.55
(d, J ) 7.8 Hz, 4H), 7.73 (m, 3H), 8.06 (d, J ) 8.3 Hz, 4H),
gave bromomethyl-porphyrin 29 in 58% yield. Reaction
of the latter with potassium thioacetate2,5 gave the free
8
.16 (d, J ) 8.0 Hz, 2H), 8.79 (dd, J ) 4.8, 13.1 Hz, 4H), 8.95
base porphyrin 18 in 36% yield. Subsequent metalation
with zinc acetate afforded the desired porphyrin Zn -18.
(
d, J ) 4.8 Hz, 2H), 9.47 (d, J ) 4.8 Hz, 2H); MALDI-MS
+
(POPOP) obsd 579.8 [(M - SAc) ]; FAB-MS obsd 654.2484,
IV. Ou tlook . The design of molecules for information-
storage applications in a hybrid molecule-chip architec-
ture requires consideration of a number of factors. Some
factors bear on performance, such as electron-transfer
rates and charge-retention times, while others concern
fabrication, such as ensuring the electrolyte is located
adjacent to the charge-storage molecules in the memory
cells. The charge-storage molecules described herein have
been designed to probe several of these factors. Tailoring
the nature of the surface attachment group (O, S, Se) and
the facial encumbrance of the porphyrin will enable
studies of charge-storage properties. Porphyrins with a
derivatizable functional group distal to the surface may
facilitate fabrication and enable studies of electrolyte
placement and how different electrolytes alter charge-
calcd 654.2453 (C H N OS); λ 420, 519, 553, 596, 654 nm.
4
3
34
4
abs
Zn (II)-5-(S -Ace t ylt h iom e t h yl)-15-p h e n yl-10,20-d i-p -
tolylp or p h yr in (Zn -2b). A solution of porphyrin 2b (88 mg,
0
.13 mmol) in CHCl
Zn(OAc) ‚2H O (147 mg, 0.676 mmol) in methanol (3 mL) at
room temperature for 2 h. Chromatography [CH Cl /ethyl
3
(15 mL) was treated with a solution of
2
2
2
2
1
acetate (98:2)] afforded a purple solid (81 mg, 84%): H NMR
δ 2.42 (s, 3H), 2.73 (s, 6H), 6.61 (s, 2H), 7.56 (d, J ) 8.0 Hz,
4
H), 7.75 (m, 3H), 8.07 (d, J ) 8.0 Hz, 4H), 8.18 (d, J ) 7.6
Hz, 2H), 8.88-8.92 (m, 4H), 9.03 (d, J ) 4.4 Hz, 2H), 9.52 (d,
+
J ) 4.4 Hz, 2H); LD-MS obsd 642.7 [(M - SAc) ]; FAB-MS
+
obsd 717.1693, calcd 717.1667 [(M + H) ] (M ) C43
32 4
H N -
OSZn); λabs 427, 555, 593 nm.
5
-(Se-Acetylselen om eth yl)-15-ph en yl-10,20-di-p-tolylpor -
p h yr in (2c). As described for 2a , condensation of 5-d iol
derived from 5; 138 mg, 0.200 mmol) with 4c (57 mg, 0.20
mmol) in CH Cl (80 mL) containing Yb(OTf) (160 mg, 0.257
(
2
2
3
mmol) at room temperature for 4 min followed by oxidation
with DDQ (136 mg, 0.60 mmol) and chromatography [silica,
(
(
57) Yu, L.; Lindsey, J . S. Tetrahedron 2001, 57, 9285-9298.
58) Sellner, H.; Faber, C.; Rheiner, P. B.; Seebach, D. Chem. Eur.
CH
2 2
Cl /ethyl acetate (19:1)] afforded a purple solid (25 mg,
1
J . 2000, 6, 3692-3705.
18%): H NMR δ -2.65 (br s, 2H), 2.53 (s, 3H), 2.71 (s, 6H),
6
746 J . Org. Chem., Vol. 69, No. 20, 2004

A Molecular Approach to Information Storage
.70 (s, 2H), 7.55 (d, J ) 8.0 Hz, 4H), 7.73 (m, 3H), 8.06 (d, J
6
)
437 mg (72%) of KSeAc as a white solid; mp 120-130 °C dec
(lit.27 mp 110-120 °C).
A mixture of bromoacetaldehyde diethylacetal (0.41 g, 2.1
mmol) and KSeAc (437 mg, 2.71 mmol) in anhydrous DMF (3
mL) was stirred at room temperature for 24 h. The reaction
mixture was poured into water and extracted with ethyl
acetate. The combined organic extracts were washed with
8.0 Hz, 4H), 8.17 (d, J ) 8.0 Hz, 2H), 8.77 (dd, J ) 4.7, 11.0
Hz, 4H), 8.87 (d, J ) 4.7 Hz, 2H), 9.48 (d, J ) 4.7 Hz, 2H);
+
MALDI-MS (POPOP) obsd 579.3 [(M - SeAc) ]; FAB-MS obsd
7
5
03.2001, calcd 703.1976 (C43
99, 655 nm.
34 4
H N OSe); λabs 424, 521, 557,
Zn (II)-5-(Se-Acetylselen om eth yl)-15-p h en yl-10,20-d i-p-
tolylp or p h yr in (Zn -2c). A solution of 2c (23 mg, 0.03 mmol)
in CH Cl (6 mL) was treated with a solution of Zn(OAc) ‚2H
47 mg, 0.32 mmol) in methanol (2 mL) at room temperature
for 15 min. The reaction mixture was washed with water and
brine, dried (Na SO ), and concentrated. Chromatography
CH Cl /hexanes (7:3)] afforded a purple solid (22 mg, 87%):
H NMR δ 2.48 (s, 3H), 2.72 (s, 6H), 6.63 (s, 2H), 7.55 (d, J )
2 4
water, dried (Na SO ), and concentrated. The crude product
2
2
2
2
O
was dried under vacuum to obtain Se-acetylselenomethyl-
acetaldehyde diethylacetal (3c) as a liquid (ca. 85% pure by
(
1
H NMR). This material was used directly in the next reaction.
2
4
As described for 4a with modified workup, a mixture of
crude 3c (0.30 g), pyrrole (8.70 mL, 125 mmol), and InCl (83
3
[
2
2
1
mg, 0.37 mmol) was heated at 60 °C for 12 h. Without adding
NaOH, the mixture was filtered. The filtrate was concentrated
and excess pyrrole was recovered. The resulting dark brown
solid was extracted with ethyl acetate/hexanes (1:1). Concen-
tration of the extract gave a viscous, pale yellow liquid.
Chromatography [silica, ethyl acetate/hexanes (1:4)] afforded
a viscous liquid (83 mg, 8% overall yield from diacetylselenide,
>99% purity by GC): 1H NMR δ 2.38 (s, 3H), 3.45 (d, J ) 7.4
Hz, 2H), 4.28 (t, J ) 7.5 Hz, 1H), 6.09 (m, 2H), 6.17 (m, 2H),
6.63 (m, 2H), 7.85 (br s, 2H); 13C NMR δ 30.3, 34.6, 38.6, 105.9,
7
2
.7 Hz, 4H), 7.73 (m, 3H), 8.06 (d, J ) 7.7 Hz, 4H), 8.17 (m,
H), 8.88 (dd, J ) 4.7, 11.5 Hz, 4H), 8.98 (d, J ) 4.7 Hz, 2H),
9
.49 (d, J ) 5.1 Hz, 2H); MALDI-MS (POPOP) obsd 643.6 [(M
-
+
SeAc) ]; FAB-MS obsd 765.1105, calcd 765.1111 (C43
32 4
H N -
OSeZn); λabs 429, 557, 597 nm.
S-Acetylth ioa ceta ld eh yd e Dieth yla ceta l (3b). Following
3
a procedure with slight modification, KSAc (2.56 g, 22.4 mmol)
was added to a solution of bromoacetaldehyde diethylacetal
(2.95 g, 15.0 mmol) in acetone (50 mL). The mixture was
refluxed, yielding a precipitate after a few minutes. After 24
h, the reaction mixture was cooled and filtered. Concentration
of the filtrate gave a tan liquid. Chromatography [silica,
14 2
108.2, 117.4, 132.0, 197.1. Anal. Calcd for C12H N OSe: C,
51.25; H, 5.02; N, 9.96. Found: C, 51.59; H, 5.21; N, 10.23.
Zn (II)-5-[4-(H yd r oxym e t h yl)p h e n yl]-10,15,20-t r i-p -
tolylp or p h yr in (Zn -7). A sample of 11 (180 mg, 0.25 mmol)
hexanes/ethyl acetate (95:5)] gave a colorless liquid (2.27 g,
1
7
(
1
9%): H NMR δ 1.21 (t, J ) 7.0 Hz, 6H), 2.35 (s, 3H), 3.11
was metalated with Zn(OAc)
room temperature for 24 h. The resulting crude Zn -11 (195
mg, 0.25 mmol) in dry THF (30 mL) was treated with LiAlH
29 mg, 0.75 mmol) under argon at room temperature for 1 h.
Methanol and water were then added slowly. The mixture was
extracted with CHCl . The organic layer was washed with
water, dried (Na SO ), concentrated, and chromatographed
(CHCl , containing 0-10% THF). The resulting product was
washed with methanol, affording a purple solid (178 mg,
2
‚2H
2
O (275 mg, 1.25 mmol) at
d, J ) 5.5 Hz, 2H), 3.55-3.67 (m, 4H), 4.50 (t, J ) 5.4 Hz,
1
3
H); C NMR δ 15.1, 30.4, 32.2, 62.3, 101.1, 195.4. Anal. Calcd
S: C, 49.97; H, 8.39; S, 16.68. Found: C, 49.42; H,
.30; S, 16.56.
-(Hyd r oxym eth yl)d ip yr r om eth a n e (4a ). Following a
4
8 16 3
for C H O
(
8
5
3
2
9
new procedure, a solution of glycolaldehyde diethylacetal
2.70 g, 20.1 mmol) and pyrrole (139 mL, 2.00 mol) was
degassed with a stream of argon for 5 min. InCl (0.45 g, 2.0
2
4
(
3
3
1
mmol) was added and the mixture was heated at 60 °C for 2
h. The heat source was removed, and a sample of solid NaOH
8
95%): H NMR (THF-d ) δ 2.69 (s, 9H), 4.44 (t, J ) 6.0 Hz,
1H), 4.93 (d, J ) 6.0 Hz, 2H), 7.55 (d, J ) 7.8 Hz, 6H), 7.73 (d,
J ) 8.1 Hz, 2H), 8.07 (d, J ) 7.2 Hz, 6H), 8.14 (d, J ) 7.8 Hz,
2H), 8.83 (s, 8H); LD-MS obsd 747.97; FAB-MS obsd 748.2217,
(0.24 g, 6.0 mmol) was added. The mixture was stirred for 30
min and then filtered. The filtrate was concentrated and excess
pyrrole was removed. The resulting dark brown solid was
extracted with ethyl acetate/hexanes (1:1). The ethyl acetate/
hexanes extract was concentrated affording a pale yellow solid.
Chromatography [silica, 6.0 × 10 cm, ethyl acetate/hexanes
calcd 748.2181 (C48
36 4
H N OZn); λabs 420, 549, 587 nm.
Zn (II)-5-[4-(Hydr oxym eth yl)ph en yl]-10,15,20-tr is(tr idec-
7
-yl)p or p h yr in (Zn -8). A solution of Zn -14 (90.0 mg, 85.3
µmol) in dry THF (10 mL) was treated with LiAlH
90 µmol) at room temperature for 2 h. Methanol (5 mL) was
slowly added and the mixture was filtered. The filtrate was
concentrated and chromatographed [silica, CHCl /hexanes (3:
)], affording the title compound in the first major band
4
(11.0 mg,
(
1:1); (400-1000 mL)] followed by concentration of the eluted
2
product gave a white solid (2.16 g, 61%): mp 83 °C; >99%
purity by GC; H NMR δ 1.93 (t, J ) 6.3 Hz, 1H), 4.10 (d, J )
1
3
5
2
1
6
.6 Hz, 2H), 4.26 (t, J ) 5.0 Hz, 1H), 6.09 (m, 2H), 6.19 (m,
1
H), 6.73 (m, 2H), 8.29 (br s, 2H); 13C NMR δ 40.2, 65.8, 106.0,
followed by a small amount of (demetalated) free base por-
phyrin alcohol in a second band. The first band was concen-
trated, affording the title compound as a purple solid (35 mg,
08.6, 117.7, 130.5. Anal. Calcd for C10
.86; N, 15.90. Found: C, 67.98; H, 6.87; N, 15.85.
-(S-Acet ylt h iom et h yl)d ip yr r om et h a n e (4b). As de-
scribed for 4a , a mixture of 3b (1.87 g, 9.73 mmol), pyrrole
67.5 mL, 0.97 mol), and InCl (0.65 g, 2.9 mmol) was heated
at 60 °C for 10 h. Workup including addition of solid NaOH
0.35 g, 8.8 mmol), recovery of excess pyrrole, extraction with
ethyl acetate/hexanes (1:1), and chromatography [silica, CH
Cl /hexanes (1:1)] afforded a viscous liquid (1.09 g, 48% yield,
99% purity by GC): H NMR δ 2.31 (s, 3H), 3.45 (d, J ) 7.7
Hz, 2H), 4.24 (t, J ) 7.5 Hz, 1H), 6.08 (m, 2H), 6.16 (m, 2H),
12 2
H N O: C, 68.16; H,
1
5
80%): H NMR δ 0.68-0.74 (m, 18H), 1.04-1.38 (m, 48H),
1.97 (br s, 1H), 2.70-2.83 (m, 6H), 2.88-3.01 (m, 6H), 5.07 (s,
2H), 5.15-5.27 (m, 3H), 7.73 (d, J ) 7.6 Hz, 2H), 8.18 (d, J )
8.4 Hz, 2H), 8.86-8.88 (m, 2H), 9.58-9.80 (m, 6H); MALDI-
(
3
+
(
MS (POPOP) obsd 1027.5, 942.7 [(M - n-hexyl) ]; FAB-MS
2
-
96 4
obsd 1024.6888, calcd 1024.6876 (C66H N OZn); λabs 424, 555,
2
593 nm; λem (λex ) 550 nm) 611, 659 nm.
1
>
5
-[4-(Meth oxyca r bon yl)p h en yl]-10,15,20-tr i-p-tolylp or -
26
p h yr in (11). Following a general procedure, a sample of 9
3.31 g, 7.00 mmol) was reduced with NaBH (5.30 g, 140
mmol) in dry THF/methanol (154 mL, 10:1) and the resulting
-d iol was condensed with 10 (1.96 g, 7.00 mmol) in acetoni-
1
3
6
1
6
.66 (m, 2H), 7.91 (br s, 2H); C NMR δ 30.7, 33.9, 38.0, 106.2,
08.3, 117.7, 131.4, 196.4. Anal. Calcd for C12 OS: C,
1.51; H, 6.02; N, 11.96, S, 13.68. Found: C, 62.69; H, 6.03;
(
4
14 2
H N
9
N, 12.20; S, 12.33.
trile (1.4 L) containing TFA (3.22 mL) at room temperature.
Subsequent oxidation with DDQ (3.18 g, 14.0 mmol) and
workup afforded a purple solid (798 mg, 16%): 1H NMR (THF-
5
-(Se-Acetylselen om eth yl)d ip yr r om eth a n e (4c). Fol-
2
7
lowing a procedure with a slight modification, KOMe (0.25
g, 3.6 mmol) was added to a solution of diacetylselenide (0.62
g, 3.8 mmol) in a mixed solvent (10 mL) of anhydrous ether/
hexanes (1:1) at 0 °C. The mixture was stirred for 3 h. The
supernatant liquid was removed by syringe and the resulting
precipitate was washed with hexanes (2 × 3 mL), affording
d ) δ -2.71 (s, 2H), 2.68 (s, 9H), 4.05 (s, 3H), 7.58 (d, J ) 7.5
8
Hz, 6H), 8.08 (d, J ) 7.2 Hz, 6H), 8.31 (d, J ) 7.4 Hz, 2H),
8.43 (d, J ) 9.0 Hz, 2H), 8.77 (d, J ) 4.5 Hz, 2H), 8.84 (d, J )
7.5 Hz, 6H); LD-MS obsd 714.53; FAB-MS obsd 715.3069, calcd
715.3073 (C49
H
38
N
4
O
2
); λabs 419, 516, 552, 591, 647 nm.
J . Org. Chem, Vol. 69, No. 20, 2004 6747

Carcel et al.
Zn (II)-5-[4-(Met h oxyca r b on yl)p h en yl]-10,15,20-t r i-p -
tolylp or p h yr in (Zn -11). A solution of 11 (72 mg, 0.10 mmol)
(s, 1H); LD-MS obsd 821.16; FAB-MS obsd 818.2607, calcd
818.2599 (C52
42 4 2
H N O Zn); λabs 424, 550, 593 nm.
in CHCl
.50 mmol) in methanol (1 mL) at room temperature for 4 h.
The mixture was washed with saturated aqueous NaHCO and
water. The organic layer was dried (Na SO ), concentrated,
and chromatographed (silica, CHCl ). The resulting product
was washed with methanol, affording a purple solid (60 mg,
3
(30 mL) was treated with Zn(OAc)
2
‚2H
2
O (110 mg,
5-[4-(S-Acetylth iom eth yl)p h en yl]-15-(4-for m ylp h en yl)-
10,20-d im esitylp or p h yr in (16). Following a standard pro-
cedure,50 a sample of porphyrin 24 (51.4 mg, 0.057 mmol) in
CH Cl (14 mL) was treated with TFA/H O (1.4 mL, 1:1 v/v)
0
3
2
4
2
2
2
3
at room temperature for 16 h. The solution was taken up in
additional CH Cl . The organic layer was washed with 5%
2
2
1
7
7%): H NMR (THF-d
8
) δ 2.69 (s, 9H), 4.05 (s, 3H), 7.55 (d,
3 2 4
aqueous NaHCO and water, dried (Na SO ), and chromato-
J ) 7.5 Hz, 6H), 8.07 (d, J ) 8.1 Hz, 6H), 8.30 (d, J ) 8.1 Hz,
graphed [silica, ether/hexanes (1:2)], affording a purple powder
(41.5 mg, 89%): 1H NMR δ -2.61 (s, 2H), 1.84 (s, 12H), 2.50
(s, 3H), 2.63 (s, 6H), 4.47 (s, 2H), 7.29 (s, 4H), 7.67 (d, J ) 8.1
Hz, 2H), 8.15 (d, J ) 8.4 Hz, 2H), 8.27 (d, J ) 7.8 Hz, 2H),
8.41 (d, J ) 7.6 Hz, 2H), 8.70-8.73 (m, 6H), 8.81 (d, J ) 4.8
2
4
H), 8.41 (d, J ) 8.7 Hz, 2H), 8.78 (d, J ) 4.5 Hz, 2H), 8.84 (s,
H), 8.86 (d, J ) 5.1 Hz, 2H); LD-MS obsd 776.0; FAB-MS
obsd 776.2181, calcd 776.2130 (C49
88 nm.
-[4-(Meth oxyca r bon yl)p h en yl]-10,15,20-tr is(tr id ec-7-
36 4 2
H N O Zn); λabs 421, 549,
5
Hz, 2H), 10.38 (s, 1H); LD-MS obsd 813.50, 738.48 [(M -
5
+
4
SAc) ]; FAB-MS obsd 815.3420, calcd 815.3420 (C54
H
46
N
4
O
2
S);
yl)p or p h yr in (14). Following a general procedure, a solution
of dipyrromethane 13 (100 mg, 304 µmol), aldehyde 12 (64.6
mg, 304 µmol), and methyl 4-formylbenzoate (25.0 mg, 152
λ
abs 422, 515, 550, 592 nm.
Zn (I I )-5 -[4 -(S -Ac e t y l t h i o m e t h y l )p h e n y l ]-1 5 -(4 -
for m ylp h en yl)-10,20-d im esitylp or p h yr in (Zn -16). A solu-
tion of porphyrin 16 (30.7 mg, 0.0376 mmol) in CHCl (15 mL)
and methanol (6 mL) was treated with Zn(OAc) ‚2H O (825
mg, 3.76 mmol) in methanol (4 mL) at room temperature for
2 2
µmol) in CH Cl (15 mL) was treated with TFA (20.8 µL, 270
µmol, 17.8 mM) at room temperature for 30 min. DDQ (104
mg, 457 µmol) was added and the reaction mixture was stirred
for 1 h. TEA (38.0 µL) was added. The reaction mixture was
3
2
2
1
5
6 h. The mixture was taken up in ethyl acetate, washed with
% aqueous NaHCO and water, dried (Na SO ), and chro-
filtered through a silica pad (CH
was concentrated. Chromatography [silica, CHCl
2
Cl
2
) and the collected fraction
/hexanes (3:
)] afforded a purple solid (25 mg, 8%): 1H NMR δ -2.48 (s,
3
2
4
3
matographed (silica, CH Cl ) to afford a purple powder (29.8
2
2
1
2
6
mg, 90%): 1H NMR δ 1.82 (s, 12H), 2.48 (s, 3H), 2.63 (s, 6H),
.46 (s, 2H), 7.28 (s, 4H), 7.65 (d, J ) 8.0 Hz, 2H), 8.16 (d, J
8.0 Hz, 2H), 8.26 (d, J ) 8.0 Hz, 2H), 8.42 (d, J ) 8.0 Hz,
H), 8.77-8.82 (m, 6H), 8.89 (d, J ) 4.8 Hz, 2H), 10.36 (s,
H), 0.69-0.74 (m, 18H), 1.08-1.35 (m, 48H), 2.70-2.80 (m,
H), 2.90-2.98 (m, 6H), 4.13 (s, 3H), 5.10-5.20 (m, 3H), 8.25
4
)
(
9
d, J ) 8.4 Hz, 2H), 8.42 (d, J ) 7.6 Hz, 2H), 8.69 (m, 2H),
2
.46-9.68 (m, 6H); MALDI-MS (POPOP) obsd 990.8, 905.7 [(M
+
+
1H); LD-MS obsd 875.58, 800.81 [(M - SAc) ]; FAB-MS obsd
44 4 2
76.2460, calcd 876.2476 (C54H N O SZn); λabs 424, 550, 589
-
H
n-hexyl) ]; FAB-MS obsd 990.7755, calcd 990.7690 (C67
-
8
nm.
98 4 2
N O
); λabs 422, 519, 555, 600 nm; λem (λex ) 550 nm) 664,
7
28 nm.
Zn (II)-5-[4-(Met h oxyca r b on yl)p h en yl]-10,15,20-t r is-
tr id ec-7-yl)p or p h yr in (Zn -14). A solution of 14 (50 mg, 50
µmol) in CHCl (8 mL) was treated with a solution of Zn(OAc)
O (55.0 mg, 252 µmol) in methanol (2 mL) at room
temperature for 16 h. The reaction mixture was washed with
water, dried (Na SO ), concentrated, and chromatographed
silica, CHCl /hexanes (3:1)], affording a purple solid (45 mg,
5%): H NMR δ 0.69-074 (m, 18H), 1.05-1.11 (m, 48H),
.74-2.84 (m, 6H), 2.92-3.01 (m, 6H), 4.13 (s, 3H), 5.21-5.24
5
-F or m yl-15-(4-h yd r oxym eth ylp h en yl)-10,20-d im esit-
5
7
ylp or p h yr in (17). Following a standard procedure, a mix-
ture of porphyrin 28 (31 mg, 0.047 mmol), K CO (63.3 mg,
.458 mmol), Pd(PPh (8.4 mg, 7.2 µmol), and 4-hydroxy-
(
2
3
3
2
‚
0
3 4
)
2
H
2
methylphenylboronic acid (15.6 mg, 0.103 mmol) in DMF (7.5
mL) and toluene (7.5 mL) was heated at 90 °C under argon
2
4
for 21 h. Then, the reaction mixture was taken up in CH
washed several times with water, dried (Na SO ), and chro-
matographed (silica, CH Cl ) to afford a purple solid (25.2 mg,
8%): H NMR δ -1.76 (s, 2H), 1.84 (s, 12H), 2.63 (s, 6H),
.05 (s, 2H), 7.29 (s, 4H), 7.75 (d, J ) 8.0 Hz, 2H), 8.17 (d, J
8.0 Hz, 2H), 8.56 (d, J ) 4.4 Hz, 2H), 8.72 (d, J ) 4.8 Hz,
H), 8.84 (d, J ) 4.8 Hz, 2H), 9.98 (d, J ) 4.8 Hz, 2H), 12.46
s, 1H); LD-MS obsd 679.64; FAB-MS obsd 680.3159, calcd
80.3151 (C46 ); λabs 426, 526, 567, 599, 656 nm.
Zn (II)-5-F or m yl-15-(4-h yd r oxym eth ylp h en yl)-10,20-d i-
m esitylp or p h yr in (Zn -17). A solution of porphyrin 17 (24
mg, 0.035 mmol) in CHCl (10 mL) and methanol (6 mL) was
treated with Zn(OAc) ‚2H O (580 mg, 2.64 mmol) at room
temperature for 2.5 h. Standard workup including chroma-
2 2
Cl ,
[
8
2
3
1
2
4
2
2
1
7
5
)
2
(
m, 3H), 8.10 (s, 2H), 8.27 (d, J ) 8.0 Hz, 2H), 8.42 (d, J ) 8.0
Hz, 2H), 8.79-8.82 (m, 2H), 9.60-9.80 (m, 4H); MALDI-MS
+
(
1
dithranol) obsd 1057.0, 969.6 [(M - n-hexyl) ]; FAB-MS obsd
052.6875, calcd 1052.6825 (C67 Zn); λabs 425, 555, 593
nm; λem (λex ) 550 nm) 613, 659 nm.
-(4-F or m ylp h e n yl)-15-[4-(h yd r oxym e t h yl)p h e n yl]-
0,20-d im esitylp or p h yr in (15). A solution of porphyrin 21
42 mg, 0.056 mmol) in CH Cl (40 mL) under argon was
96 4 2
H N O
(
6
40 4 2
H N O
5
1
(
2
2
3
treated with PCC (13 mg, 0.060 mmol). The resulting green
mixture was stirred under argon at room temperature. After
2
2
3
[
(
h, the mixture was concentrated and chromatographed
silica, CH Cl f CH Cl /ethyl acetate (2:1)]. The second band
purple) afforded a purple powder (19.2 mg, 46%): H NMR δ
2.63 (s, 2H), 1.83 (s, 12H), 1.99 (m, 1H), 2.63 (s, 6H), 5.07 (d,
tography (silica, CH
2
Cl
8
2
) gave a purple-green solid (23.5 mg,
) δ 1.86 (s, 12H), 2.64 (s, 6H), 4.50 (m,
2
2
2
2
8%): 1H NMR (THF-d
8
1
2
1
H), 4.92 (d, J ) 5.6 Hz, 2H), 7.31 (s, 4H), 7.72 (d, J ) 8.0 Hz,
H), 8.09 (d, J ) 8.0 Hz, 2H), 8.52 (d, J ) 4.4 Hz, 2H), 8.70 (d,
-
J ) 3.6 Hz, 2H), 7.28 (s, 4H), 7.75 (d, J ) 8 Hz, 2H), 8.22 (d,
J ) 4.4 Hz, 2H), 8.76 (d, J ) 4.4 Hz, 2H), 10.10 (d, J ) 4.8 Hz,
J ) 8 Hz, 2H), 8.27 (d, J ) 8 Hz, 2H), 8.41 (d, J ) 8 Hz, 2H),
2
H), 12.53 (s, 1H); LD-MS obsd 743.88; FAB-MS obsd 742.2278,
calcd 742.2286 (C46 Zn); λabs 431, 562, 601 nm.
-[4-(S-Acet ylt h iom et h yl)p h en yl]-15-for m yl-10,20-d i-
8
.70 (m, 6H), 8.80 (d, J ) 4.8 Hz, 2H), 10.38 (s, 1H); LD-MS
obsd 757.82;FAB-MS obsd 756.3492,calcd 756.3464(C52 );
abs 421, 515, 549, 593, 649 nm.
Zn (II)-5-(4-For m ylph en yl)-15-[4-(h ydr oxym eth yl)ph en -
yl]-10,20-d im esitylp or p h yr in (Zn -15). A solution of por-
phyrin 15 (19 mg, 0.025 mmol) in CHCl (11 mL) and methanol
2 mL) was treated with Zn(OAc) ‚2H O (450 mg, 2.05 mmol)
in methanol (6 mL) for 2.5 h at room temperature. Standard
workup including chromatography (silica, CH Cl ) gave a
purple solid (20.6 mg, quantitative): H NMR δ 1.83 (s, 12H),
38 4 2
H N O
44 4 2
H N O
5
λ
2,5
m esitylp or p h yr in (18). Following a general procedure,
a
solution of porphyrin 29 (10 mg, 0.013 mmol) in acetone (1.5
mL) was treated with potassium thioacetate (22 mg, 0.19
mmol). The reaction mixture was heated to reflux and followed
by TLC. After 4 h, the starting porphyrin 29 was consumed.
The mixture was allowed to cool to room temperature, then
CH Cl and water were added. The organic layer was washed
3
(
2
2
2
2
2
2
1
with 10% aqueous NaHCO
3
and water and dried (Na
2 4
SO ).
2
2
.63 (s, 6H), 4.77 (s, 2H), 7.28 (s, 4H), 7.57 (d, J ) 8.0 Hz,
H), 8.18 (d, J ) 8.0 Hz, 2H), 8.25 (d, J ) 8.0 Hz, 2H), 8.42 (d,
Purification by chromatography (silica, CH
2
Cl /hexanes) gave
2
a purple solid (3.6 mg, 36%): 1H NMR δ -1.80 (br s, 2H), 1.84
(s, 12H), 2.49 (s, 3H), 2.64 (s, 6H), 4.45 (s, 2H), 7.29 (s, 4H),
7.66 (d, J ) 8.0 Hz, 2H), 8.10 (d, J ) 8.0 Hz, 2H), 8.55 (d, J )
J ) 8 Hz, 2H), 8.78 (d, J ) 4.8 Hz, 2H), 8.80 (d, J ) 4.4 Hz,
2
H), 8.82 (d, J ) 4.8 Hz, 2H), 8.86 (d, J ) 4.8 Hz, 2H), 10.34
6
748 J . Org. Chem., Vol. 69, No. 20, 2004

A Molecular Approach to Information Storage
4
9
6
.4 Hz, 2H), 8.71 (d, J ) 4.4 Hz, 2H), 8.83 (d, J ) 5.2 Hz, 2H),
.97 (d, J ) 4.8 Hz, 2H), 12.45 (s, 1H); LD-MS obsd 738.97,
Cu (II)-5-F or m yl-10,20-d im esitylp or p h yr in (Cu -26). Fol-
lowing a standard procedure,52 a solution of porphyrin Cu -25
(333 mg, 0.547 mmol) in 1,2-dichloroethane (130 mL) was
added dropwise to the Vilsmeier reagent (freshly prepared at
+
64.05 [(M - SAc) ]; FAB-MS obsd 738.3066, calcd 738.3028
48 42 4 2
(C H N O S); λabs 427, 525, 566, 659 nm.
0
3
°C from 3.2 mL of anhydrous DMF and 3.8 mL of POCl )
Zn (II)-5-[4-(S -Ace t ylt h iom e t h yl)p h e n yl]-15-for m yl-
0,20-d im esitylp or p h yr in (Zn -18). A solution of porphyrin
and the mixture was then heated at 60 °C. After 2 h, TLC
analysis indicated the absence of any starting porphyrin Cu -
1
1
8 (3 mg, 0.004 mmol) in CHCl
‚2H O (90 mg, 0.41 mmol) at room temperature
for 4 h. Standard workup including chromatography [silica,
CH Cl /ethyl acetate (8:1)] gave a purple-green solid (3.2 mg,
quantitative): H NMR (THF-d
3
/MeOH (5 mL, 3:2) was treated
2
5. A solution of saturated aqueous NaOAc (60 mL) was added
with Zn(OAc)
2
2
dropwise and the mixture was heated for another 90 min. The
organic layer was separated and the aqueous layer extracted
with CH Cl . The organic layers were combined, washed with
2 2
2
2
1
8
) δ 1.85 (s, 12H), 2.44 (s, 3H),
.62 (s, 6H), 4.46 (s, 2H), 7.31 (s, 4H), 7.66 (d, J ) 8.0 Hz,
H), 8.07 (d, J ) 7.6 Hz, 2H), 8.52 (d, J ) 4.4 Hz, 2H), 8.69 (d,
water, dried (Na
chromatography (silica, CH
powder (291 mg, 84%): LD-MS obsd 635.45; FAB-MS obsd
635.1885, calcd 635.1872 (C H CuN O); λ 420, 548, 589 nm.
2
SO
4
), and concentrated. Purification by
2
2
2
2
Cl /hexanes) afforded a purple
J ) 4.4 Hz, 2H), 8.75 (d, J ) 4.8 Hz, 2H), 10.10 (d, J ) 4.8 Hz,
+
2
H), 12.53 (s, 1H); LD-MS obsd 798.08, 723.20 [(M - SAc) ];
FAB-MS obsd 800.2186, calcd 800.2163 (C48 SZn); λabs
31, 560, 601 nm.
,15-Dim esityl-10,20-bis[4-(m eth oxyca r bon yl)p h en yl]-
39 32
4
abs
H
40
N
4
O
2
5-F or m yl-10,20-d im esitylp or p h yr in (26). Following a
standard procedure,52 a solution of porphyrin Cu -26 (287 mg,
0.451 mmol) in TFA (25 mL) was treated with concentrated
4
5
4
6
p or p h yr in (20). Following a standard procedure, a solution
of 19 (203 mg, 0.769 mmol) and methyl 4-formylbenzoate (126
mg, 0.768 mmol) in CH
µL, 1.95 mmol) at room temperature. After 40 min, DDQ (262
mg, 1.15 mmol) was added. After 60 min, TEA (150 µL) was
added. The reaction mixture was concentrated and chromato-
H
2
SO
an aliquot of the solution was removed and treated with a
saturated aqueous solution of NaHCO and extracted with
CH Cl . TLC analysis revealed that the copper complex was
consumed. The reaction mixture was worked up with saturated
aqueous NaHCO and CH Cl . The organic layer was dried
2
(Na SO ), concentrated, and chromatographed (silica, CH Cl )
4
(10 mL) and stirred at room temperature. After 90 min,
2
Cl
2
(76 mL) was treated with TFA (150
3
2
2
3
2
2
graphed [silica, CH
2
Cl
2
1
/hexanes (1:1)], affording a purple
2
4
2
1
powder (76.9 mg, 25%): H NMR δ -2.64 (s, 2H), 1.83 (s, 12H),
2
4
to give a purple powder (232 mg, 89%): H NMR δ -2.24 (s,
2H), 1.86 (s, 12H), 2.68 (s, 6H), 7.34 (s, 4H), 8.74 (d, J ) 4.4
Hz, 2H), 8.93 (d, J ) 4.8 Hz, 2H), 9.23 (d, J ) 4.4 Hz, 2H),
10.06 (br s, 2H), 10.17 (s, 1H), 12.57 (s, 1H); LD-MS obsd
.63 (s, 6H), 4.11 (s, 6H), 7.28 (s, 4H), 8.31 (d, J ) 8.0 Hz,
H), 8.43 (d, J ) 8.0 Hz, 4H), 8.71 (d, J ) 4.8 Hz, 4H), 8.74 (d,
J ) 5.2 Hz, 4H); LD-MS obsd 813.84; FAB-MS obsd 815.3599,
calcd 815.3597 (C54
,15-Bis[4-(h ydr oxym eth yl)ph en yl]-10,20-dim esitylpor -
p h yr in (21). A solution of porphyrin 20 (76 mg, 0.093 mmol)
in dry THF (20 mL) was treated with LiAlH (28 mg, 0.74
H
46
N
4
O
4
); λabs 421, 515, 548, 593, 649 nm.
574.38; FAB-MS obsd 574.2740, calcd 574.2733 (C39
abs 423, 520, 559, 597, 652 nm.
5,15-Dim esit yl-10-(5,5-d im et h yl-1,3-d ioxa n -2-yl)p or -
34 4
H N O);
λ
5
p h yr in (27). Following a literature procedure,49 a mixture of
porphyrin 26 (168 mg, 0.292 mmol), neopentyl glycol (36.5 mg,
0.350 mmol), and p-toluenesulfonic acid monohydrate (5.5 mg,
0.029 mmol) in benzene (50 mL) was heated to reflux. After 4
h, TLC analysis showed almost no starting material. The
reaction mixture was cooled to room temperature, diluted with
4
mmol) at room temperature under argon. The progress of the
reaction was monitored by TLC and LD-MS. After 1 h,
methanol was added slowly. The reaction mixture was filtered
and the filtrate was concentrated. Purification by chromatog-
2 2 2 2
raphy [silica, CH Cl f CH Cl /ethyl acetate (2:1)] afforded a
1
dark purple powder (61.5 mg, 87%): H NMR δ -2.61 (s, 2H),
1
4
CH
The organic layer was dried (Na
chromatographed (alumina, CH Cl /hexanes) to afford a purple
2
Cl
2
, and washed with 10% aqueous NaHCO
3
and water.
.84 (s, 12H), 2.00 (m, 2H), 2.63 (s, 6H), 5.06 (s, 4H), 7.28 (s,
H), 7.74 (d, J ) 8.0 Hz, 4H), 8.22 (d, J ) 8.0 Hz, 4H), 8.69 (d,
2
SO ), concentrated, and
4
2
2
1
J ) 4.4 Hz, 4H), 8.80 (d, J ) 4.4 Hz, 4H); LD-MS obsd 757.67;
solid (174 mg, 90%): H NMR δ -3.02 (s, 2H), 1.13 (s, 3H),
1.85 (s, 12H), 1.94 (s, 3H), 2.68 (s, 6H), 4.34 (d, J ) 11.2 Hz,
2H), 4.38 (d, J ) 11.6 Hz, 2H), 7.34 (s, 4H), 8.03 (s, 1H), 8.83
FAB-MS obsd 758.3666, calcd 758.3621 (C52
15, 548, 592, 650 nm.
-[4-(S-Acet ylt h iom et h yl)p h en yl]-10,20-d im esit yl-15-
4-(5,5-d im eth yl-1,3-d ioxa n -2-yl)p h en yl]p or p h yr in (24).
46 4 2
H N O ); λabs 420,
5
(
d, J ) 4.4 Hz, 2H), 8.91 (d, J ) 4.4 Hz, 2H), 9.28 (d, J ) 4.4
5
Hz, 2H), 9.98 (br s, 2H), 10.17 (s, 1H); LD-MS obsd 660.53,
[
+
4
574.42 [(M - C
); λabs 414, 507, 583, 636 nm.
5-Br om o-15-for m yl-10,20-d im esitylp or p h yr in (28). Fol-
lowing a standard procedure,54 a solution of 27 (140 mg, 212
(47 mL) was cooled in an ice bath and treated
5
H10O) ]; FAB-MS obsd 660.3499, calcd 660.3464
Following a general procedure, a solution of aldehyde 22 (113
mg, 0.513 mmol), aldehyde 23 (99 mg, 0.51 mmol), and
5
44 44 4 2
(C H N O
2 2
-mesityldipyrromethane (19) (270 mg, 1.02 mmol) in CH Cl
(
100 mL) was treated with TFA (140 µL, 1.82 mmol) at room
temperature for 30 min. DDQ (348 mg, 1.53 mmol) was added.
µmol) in CHCl
3
After 90 min, TEA (150 µL) was added. The reaction mixture
was filtered through a short silica column (CH
with pyridine (190 µL) and NBS (38.0 mg, 213 µmol). After 15
2
Cl
2
). The
min, the reaction was quenched by acetone (10 mL) and the
resulting mixture of three porphyrins was concentrated,
dissolved in toluene, and chromatographed (silica, toluene).
2 2
solvent was evaporated. TLC analysis [CH Cl /hexanes (1:1)]
of the resulting crude mixture exhibited the formation of a
brominated product and a small amount of porphyrin 28. The
2 2
crude mixture was dissolved in CH Cl (53 mL) and the
solution was treated with a solution of TFA/water (5.3 mL,
1:1) at room temperature. After 16 h, the organic phase was
The second purple band was isolated and precipitated (CH
Cl
/MeOH) to give a purple powder (51.4 mg, 11%): 1H NMR
δ -2.65 (s, 2H), 0.92 (s, 3H), 1.46 (s, 3H), 1.83 (s, 12H), 2.50
s, 3H), 2.63 (s, 6H), 3.86 (d, J ) 10.8 Hz, 2H), 3.97 (d, J )
0.5 Hz, 2H), 4.47 (s, 2H), 5.75 (s, 1H), 7.28 (s, 4H), 7.66 (d, J
2
-
2
(
1
separated, washed with 5% aqueous NaHCO
concentrated to dryness. Chromatography [silica, CH
3
and water, and
2
Cl /
)
7.8 Hz, 2H), 7.90 (d, J ) 7.8 Hz, 2H), 8.15 (d, J ) 8.1 Hz,
2
2
5
H), 8.24 (d, J ) 7.8 Hz, 2H), 8.65-8.69 (m, 4H), 8.79 (d, J )
hexanes (1:1)] followed by trituration of the resulting solid in
methanol gave a purple solid (75 mg, 54%): 1H NMR δ -1.78
(s, 2H), 1.85 (s, 12H), 2.66 (s, 6H), 7.31 (s, 4H), 8.62 (d, J )
4.8 Hz, 2H), 8.82 (d, J ) 5.2 Hz, 2H), 9.52 (d, J ) 4.4 Hz, 2H),
+
.1 Hz, 4H); LD-MS obsd 900.59, 825.51 [(M - SAc) ]; FAB-
MS obsd 900.4100, calcd 900.4073 (C59
56 4 3
H N O S); λabs 420, 515,
5
48, 593 nm.
Cu (II)-5,15-Dim esitylp or p h yr in (Cu -25). A solution of
porphyrin 25 (365 mg, 0.668 mmol) in CHCl /methanol (2:1
v/v, 60 mL) was treated with Cu(OAc) ‚H O (2.08 g, 10.4 mmol)
at room temperature for 2.5 h. Standard workup including
chromatography (silica, CH Cl ) gave a red-purple powder (406
mg, quantitative): LD-MS obsd 607.92; FAB-MS obsd 607.1942,
calcd 607.1923 (C38 ); λabs 406, 530, 564 nm.
9
.94 (d, J ) 4.4 Hz, 2H), 12.43 (s, 1H); LD-MS obsd 653.4;
FAB-MS obsd 652.1857, calcd 652.1838 (C39
26, 529, 569, 604, 663 nm.
H
4
33BrN O); λabs
3
4
2
2
5-(4-Br om om eth ylph en yl)-15-for m yl-10,20-dim esitylpor -
p h yr in (29). Following a general procedure,58 a solution of
porphyrin 17 (24 mg, 0.035 mmol) in anhydrous ether (10 mL)
2
2
H
32CuN
4
at 0 °C under argon was treated dropwise with PBr
3
(30 µL,
J . Org. Chem, Vol. 69, No. 20, 2004 6749

Carcel et al.
0
.32 mmol). The purple solution immediately became green
and then a precipitate appeared. The mixture was stirred at
room temperature for 1 h. Then CH Cl was added to give a
green solution, which was washed with saturated aqueous
NaHCO and water. The organic layer was dried (Na SO ) and
chromatographed (silica, CH Cl /hexanes), affording a purple
DMEA (award no. DMEA90-02-2-216), and by Zetta-
Core, Inc. Mass spectra were obtained at the Mass
Spectrometry Laboratory for Biotechnology at North
Carolina State University. Partial funding for the
Facility was obtained from the North Carolina Biotech-
nology Center and the National Science Foundation.
2
2
3
2
4
2
2
1
solid (15.3 mg, 58%): H NMR δ -1.81 (br s, 2H), 1.84 (s, 12H),
2
2
.64 (s, 6H), 4.83 (s, 2H), 7.29 (s, 4H), 7.77 (d, J ) 8.0 Hz,
H), 8.15 (d, J ) 7.6 Hz, 2H), 8.56 (d, J ) 4.4 Hz, 2H), 8.71 (d,
Su p p or tin g In for m a tion Ava ila ble: General experimen-
tal section and characterization data for new compounds,
J ) 4.8 Hz, 2H), 8.84 (d, J ) 5.2 Hz, 2H), 9.97 (d, J ) 4.4 Hz,
including 1H NMR and 13C NMR spectra for all new non-
+
2
H), 12.46 (s, 1H); LD-MS obsd 741.80, 660.17 [(M - Br) ];
FAB-MS obsd 742.2335, calcd 742.2307 (C46
27, 526, 566, 658 nm.
1
porphyrin compounds, and H NMR spectra and LD-MS or
H
4
39BrN O); λabs
MALDI-MS spectra for all new porphyrins. This material is
available free of charge via the Internet at http://pubs.acs.org.
4
Ack n ow led gm en t. This work was supported by the
Center for Nanoscale Innovation in Defense and DARPA/
J O0498260
6
750 J . Org. Chem., Vol. 69, No. 20, 2004