Synthesis of Highly Fluoroalkyl-Functionalized Oligoporphyrin Systems

Article abstract of DOI:10.1002/ejoc.201402816

Four different multiporphyrin systems have been synthesized and characterized. Highly fluoroalkyl-functionalized porphyrins are the most complex objects so far to have exhibited quantum wave nature. We have functionalized larger oligoporphyrin systems with fluoroalkyl chains to increase their mass and minimize their intermolecular interactions. The to-some-extent random substitution of fluorine atoms at the periphery of the oligoporphyrins results in libraries consisting of molecules varying in both the number and spatial distribution of substituents. The mass-selected individual members of these libraries were designed for quantum interference experiments. To investigate the volatilization nature of the molecules within the library, laser desorption and post-ionization studies were performed. These studies demonstrated that molecular beams of suitable velocity and ionization cross-section can be obtained from these libraries. In particular, we present these features for two libraries, based on either a tetrahedrally arranged central porphyrin tetramer or a more planar porphyrin pentamer.

Full text of DOI:10.1002/ejoc.201402816

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
FULL PAPER
DOI: 10.1002/ejoc.201402816
Synthesis of Highly Fluoroalkyl-Functionalized Oligoporphyrin Systems
Lukas Felix,[a] Ugur Sezer,[b] Markus Arndt,[b] and Marcel Mayor*[a,c]
Keywords: Chemical libraries / Porphyrinoids / Fluorine / Aromatic substitution / Mass spectrometry
Four different multiporphyrin systems have been synthesized
and characterized. Highly fluoroalkyl-functionalized por-
phyrins are the most complex objects so far to have exhibited
quantum wave nature. We have functionalized larger oligo-
porphyrin systems with fluoroalkyl chains to increase their
mass and minimize their intermolecular interactions. The to-
some-extent random substitution of fluorine atoms at the pe-
riphery of the oligoporphyrins results in libraries consisting
of molecules varying in both the number and spatial distribu-
tion of substituents. The mass-selected individual members
of these libraries were designed for quantum interference ex-
periments. To investigate the volatilization nature of the mol-
ecules within the library, laser desorption and post-ionization
studies were performed. These studies demonstrated that
molecular beams of suitable velocity and ionization cross-
section can be obtained from these libraries. In particular,
we present these features for two libraries, based on either a
tetrahedrally arranged central porphyrin tetramer or a more
planar porphyrin pentamer.
with the mass of interest is abundant enough and its mass
is sufficiently different to those of its closest members in the
library. This concept was successfully demonstrated with a
library obtained by random partial substitution of fluorine
atoms by fluoroalkylthiolates on meso-tetrakis(pentafluoro-
phenyl)porphyrins.[12] To explore the limitations of quan-
tum experiments, high-mass molecules or nanoparticles that
can be volatilized with a controlled distribution of mass are
required. These molecules or particles should be neutral to
avoid perturbation by electric fields. Detection after the in-
terference experiment is facilitated if the particles can be
ionized with ultraviolet radiation. To the best of our knowl-
edge, suitable heavy compounds combining the features re-
quired for slow beam formation and subsequent photoioni-
zation do not yet exist and have therefore to be designed
and synthesized. An ideal compound should be stable
enough to survive short exposure to temperatures up to
1000 K during laser pulses. In addition, their polarizability/
mass ratio should be small to minimize intermolecular
binding and facilitate laser evaporation or sublimation.
Earlier experiments have already indicated that fluoroalk-
ylsulfanyl side-chains can render large molecules more vola-
tile.[1,3–6] Even for massive molecules, their vapor pressure
reached impressive values if they were suitably function-
alized at their periphery.[14,15] In a first approach we func-
tionalized the periphery of porphyrin precursors with per-
fluorinated alkylthiolates with a well-defined substitution
pattern[10] as well as randomly to provide a library of poten-
tial particles with well-defined molecular weights.[12]
Introduction
The quantum wave nature of massive particles is a funda-
mental concept of physics and chemistry. It has been seen
for electrons,[1] neutrons,[2] atoms,[3] and even complex mol-
ecules.[4,5] Quantum delocalization of hot molecules was
[6]
first observed in 1999 with C60 and C70.[7] Full-fledged
three-grating molecule interferometers[8] were successfully
operated with organic dyes such as tetraphenylporphyrin
(TPP).[9] These experiments relied on the availability of
stable and lasting effusive thermal beams, a great challenge
for complex macromolecules. The use of fluorinated fuller-
ene C60F48 was a first step in this direction.[9] Quantum
experiments with even larger compounds became possible
by attaching fluoroalkyl chains to stable core struc-
tures.[10,11] Recently, this strategy was successfully applied
to components with a molecular weight even beyond
10000 g/mol, selected from a molecular library consisting of
porphyrin structures comprising different numbers of
fluoroalkylsulfanyl substituents.[12,13] In the experimental
set-up, particles with a small mass range were exclusively
observed. Therefore libraries composed of particles of dif-
ferent masses are perfectly suitable as long as the particle
[a] Department of Chemistry, University of Basel,
St. Johannsring 19, 4056 Basel, Switzerland
E-mail: marcel.mayor@unibas.ch
http://www.chemie.unibas.ch/~mayor/
[b] University of Vienna, Faculty of Physics, VCQ&QuNaBioS,
Boltzmanngasse 5, 1090 Vienna, Austria
In this work we have extended the library concept to even
heavier particles by using oligoporphyrin systems that are
not only the core subunits of a larger mass, but that also
present an increased number of fluorine atoms that can be
[c] Karlsruhe Institute of Technology (KIT), Institute of
Nanotechnology,
P. O. Box 3640, 76021 Karlsruhe, Germany
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201402816.
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
L. Felix, U. Sezer, M. Arndt, M. Mayor
FULL PAPER
substituted by perfluorinated alkylthiolates. The libraries core units. To the best of our knowledge, there has been
thereby obtained consist of molecular components of high only one example of a photoionizable fluorinated porphyrin
mass, high volatility, and ionizability under single-photon library reported in the literature[13] so far. By using 1 and 2
excitation at 157.6 nm.
as precursors of libraries, the mass of the library compo-
nents can be increased. In addition, we can investigate the
difference between the extended conjugation in 2 and the
limited conjugation in 1. The conjugation in 1 is broken
by the tetrahedral sp3-hybridized carbon center. Pentamer 2
consists of porphyrin centers that are interlinked by ethynyl
Results and Discussion
Molecular Design
We present the synthesis of four different multiporphyrin bridges at their meso positions. Acetylene-linked π systems
systems that consist of 2–5 central porphyrin cores and are known for their reduced conjugation due to the mis-
pentafluorophenyl subunits. The synthesis and properties of match of π–π and π*–π* interactions at the sp1–sp2 connec-
oligoporphyrin systems are well understood and described tion. However, porphyrins interlinked directly by meso-eth-
in the literature.[16–20] These compounds are appealing start- ynyl units are reported to prevent the π systems from twist-
ing materials for the assembly of molecular libraries for in- ing out of plane, which extends the conjugation in the case
terference experiments as the molecular weights of their of 2.[21,22] We hypothesized that the difference in planarity
components can be tailored by varying the number and/or and the extent of conjugation might be reflected in different
length of the perfluoroalkyl side-chains. Also, their desorp- desorption and photo-ionization behavior of the libraries
tion and post-ionization properties can be tuned to some obtained from both precursors.
extent by the presence or absence of metal ions in their
porphyrin systems.
To develop the synthetic procedures and investigate the
modularity of the strategy, the porphyrin dimer 3 and tri-
Of particular interest are the precursors 1 and 2, which mer 4 were also synthesized (Figure 2). These model com-
consist of four and five porphyrin subunits, respectively. As pounds can be obtained from the same monomeric por-
shown in Figure 1, up to 60 perfluoroalkyl side-chains can phyrin building blocks. As the main focus of our work is
be connected by substituting the fluorine atoms of both on volatile and photo-ionizable molecules with masses well
Figure 1. Porphyrin tetramer 1 and pentamer 2 with two different central units, namely a tetraphenylmethane and a porphyrin, respec-
tively. Both compounds have 60 peripheral fluorines that are accessible for SNAr reactions, which allows their mass to be increased by
suitable nucleophiles.
2
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
Fluoroalkyl-Functionalized Oligoporphyrin Systems
Figure 2. Porphyrin dimer 3 and trimer 4. Both are built around a central phenyl unit. Dimer 3 has 30 accessible positions for SNAr
reactions, whereas trimer 4 has 45 accessible positions.
above 20000 g/mol, these two central units (3 and 4) were
The oligoporphyrin systems can be assembled by using
less promising precursors of high-mass libraries than 1 and copper-free Sonogashira cross-coupling conditions to avoid
2.[12]
coordination of the copper ion to the multidentate por-
phyrin binding site. Similar copper-free cross-coupling reac-
tion conditions have already been used for the synthesis of
porphyrin dimers and trimers by Achelle et al. in 2011 and
are reported to be well suited to porphyrin systems.[23–27]
All the coupling reactions presented herein used the same
monomeric ethynylporphyrin building block 5 (Scheme 1),
which can be synthesized from the dipyrromethane com-
pound 6, TMS-propynal (7), and pentafluorobenzaldehyde
Synthetic Strategy
With these multiporphyrin systems in hand, molecular
libraries were obtained by attaching different numbers of
perfluoroalkylsulfanyl side-chains to the multiporphyrin
cores through a nucleophilic aromatic substitution reaction
under basic conditions.
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
L. Felix, U. Sezer, M. Arndt, M. Mayor
FULL PAPER
(8) following the general procedure reported for the synthe- methane (11), which can be obtained from tetraphenyl-
sis of unsymmetrical porphyrins by Fathalla and Jayawick- methane,[31] and porphyrin pentamer 2 was synthesized
ramarajah.[28] This statistical reaction yields three different from meso-tetrakis(4-iodophenyl)porphyrin (12) as the cen-
porphyrins, namely compound 5, meso-tetrakis(pentafluoro- tral unit, which can by synthesized as described below fol-
phenyl)porphyrin (5a), and the diethynyl derivative 5b lowing literature procedures.[30,32]
(Scheme 1). The statistical nature of the reaction lowers the
yield of 5 as the key intermediate. Dipyrromethane 6 can
Synthesis
The central units of porphyrin dimer 3 and trimer 4 were
be obtained in one step from pentafluorobenzaldehyde (8)
and pyrrole.[29,30]
synthesized following literature procedures. Tetrakis(4-
iodophenyl)methane (11) was synthesized from tetraphenyl-
methane by using the iodination conditions developed by
Aujard et al.[31] Tetrakis(4-iodophenyl)methane (11) was
obtained in 74% yield. By using the conditions developed
by Lindsey et al., meso-tetrakis(4-iodophenyl)porphyrin
(12) was obtained in a yield of 14%.[30] In the first step, the
key porphyrin building block 5 was synthesized. For this
purpose, dipyrromethane 6 was synthesized from pyrrole
and pentafluorobenzaldehyde (8) in an electrophilic aro-
matic substitution reaction of pyrrole. The reaction was
performed under acidic conditions by using trifluoroacetic
acid (TFA) in pyrrole as solvent. These conditions were
found to be ideal by Lee and Lindsey.[29,30] Following this
procedure, dipyrromethane 6 was obtained in a yield of
91%.
The trimethylsilyl-protected ethynylporphyrin key build-
ing block 5 was synthesized from dipyrromethane 6, tri-
methylsilylpropynal (7), and pentafluorobenzaldehyde (8)
by using a catalytic amount of boron trifluoride–diethyl
Scheme 1. Synthetic strategy towards the monomeric porphyrin
building block 5. The synthesis using dipyrromethane 6 and the
corresponding aldehydes 7 and 8 leads to a statistical mixture of
three different porphyrins (5, 5a, and 5b).
To connect the monomeric porphyrin 5 as efficiently as
possible by Sonogashira cross-coupling, iodine precursors
are best suited as the connecting units. 1,4-Diiodobenzene
(9) and 1,3,5-triiodobenzene (10) are commercially available
and were used as starting materials to synthesize porphyrin
dimer 3 and trimer 4, respectively. The central unit of por-
Scheme 2. Synthesis of the unsymmetric porphyrin building block
5 in a statistical reaction, the deprotected porphyrin 13 and their
zinc derivatives 14 and 15. Reagents and conditions:
a) 1. BF3·O(Et)2, CHCl3, room temp., 18 h; 2. DDQ, room temp.,
2 h, 15%; b) TBAF, CH2Cl2, 30 min, quant.; c) Zn(CH3COO)2,
phyrin tetramer 1 was derived from tetrakis(4-iodophenyl)- CH2Cl2, CH3OH, 24 h, quant.
4
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
Fluoroalkyl-Functionalized Oligoporphyrin Systems
ether as Lewis acid (Scheme 2). Subsequent oxidization Table 1. Optimization of the reaction conditions for the synthesis
of porphyrin monomer 5.[a]
with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)
6 [equiv.] 7 [equiv.] 8 [equiv.] Time [h] Oxidizing agent Yield[b] [%]
provided the desired porphyrin derivative. The reaction con-
ditions reported by Fathalla and Jayawickramarajah in
2009 for non-fluorinated porphyrins were systematically
varied (Table 1), seeking to optimize the conditions for the
fluorinated starting materials.[28,33] Longer reaction times
increased the yield, and replacing DDQ by p-chloranil re-
duced the isolated yield of the reaction. The yield was fur-
ther improved by compensating the lower reactivity of
pentafluorobenzaldehyde (8) by doubling its concentration.
The crude product was purified by filtration through sil-
ica and subsequently divided into its components by mul-
tiple column chromatography. Bu using the optimized con-
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
2
0.75
0.33
1
18
18
DDQ
DDQ
DDQ
DDQ
p-chloranil
DDQ
3
0
8
10
7
15
1.1
18
[a] All reactions were performed at room temp. and with the same
concentration and scale. [b] Isolated yields.
The TMS-masked ethynylporphyrin 5 was deprotected
ditions, the pure porphyrin 5 was obtained in a yield of by using tetrabutylammonium fluoride (TBAF) in dichloro-
15%. methane to provide the ethynyl derivative 13 in quantitative
Table 2. Sonogashira cross-coupling reaction using different central units (all yields are isolated yields).
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
L. Felix, U. Sezer, M. Arndt, M. Mayor
FULL PAPER
yield. Initial attempts to substitute the fluorine atoms of the perfluoroalkylthiolates. The peripheral nucleophilic aro-
metal-free porphyrins by perfluorinated alkylthiols were not matic substitution with fluoroalkylsulfanyl side-chains not
successful in all cases and thus a central Zn atom was in- only increases the mass of the oligoporphyrin, the reduced
serted prior to the Sonogashira cross-coupling reactions for polarizability of these chains results in low van der Waals
the synthesis of the porphyrin systems 1, 3, and 4 (the zinc interactions and thus decreases the intermolecular attrac-
porphyrin systems being 1B, 3B, and 4B). Interestingly, the tion. The peripheral substitution was performed by using
metal-free pentameric porphyrin system 2 turned out to be the commercially available 1H,1H,2H,2H-perfluorodec-
more stable under basic substitution conditions, which al- anethiol (16) under basic conditions. For the tetraporphyrin
lowed it to be used as starting material for the synthesis of 1B, 120 equiv. of the thiol 16 were heated at 90 °C for 18 h
its molecular libraries.
in the presence of K2CO3 as base. After aqueous work-up
The coordination of a central Zn atom to the porphyrin and extraction with tert-butyl methyl ether (TBME), the
was achieved by using zinc acetate in a solvent mixture of combined organic phases were concentrated and purified
dichloromethane and methanol. Porphyrin 14 was depro- by filtration through a short plug of silica. The composition
tected under the same conditions as those used for the of the obtained library 1L was analyzed by MALDI-TOF
metal-free derivative 5. The deprotected zinc ethynylpor- mass spectrometry. As expected, we observed only library
phyrin 15 was obtained in quantitative yield over two steps components with masses that differ by Δm
=
from 5. m(C10H4F17S) – m(F) = 479 – 19 = 460. The composition
With the ethynyl-functionalized porphyrins 13 and 15 in of the library is detailed in Table 3. The most abundant
hand, their reactions with different central units comprising component was 1L18 with 18 fluorine atoms substituted by
various numbers of iodine substituents were investigated for the fluoroalkylsulfanyl side-chain and a mass of 12230 amu.
the assembly of porphyrin oligomers by Sonogashira cross- The components of the library include those with between
coupling reactions, as shown in Table 2.
15 and 22 introduced fluoroalkylsulfanyl side-chains. It is
The reactions were performed under copper-free cross- noteworthy that for a given member of the library 1Lx, the
coupling reaction conditions following the protocol re- number x of fluoroalkylsulfanyl side-chains is the same in
ported in 2011 by Achelle at al.[23] Preliminary attempts all molecules, but the library is composed of structural iso-
using classical conditions and catalytic amounts of copper mers. For all molecules of the library member 1Lx, exactly
iodide resulted in the formation of the diacetylene as the x of the 60 fluorine atoms have been substituted by fluori-
main product. The competing formation of this homo- nated alkylthiolates, but which of the fluorine atoms has
coupled product not only reduced the yield of the desired been substituted is to some extent a random process. This
porphyrin oligomers, but also the separation of the two results in some structural diversity between the isomers that
structures by column chromatography turned out to be ex- define the library member 1Lx. However, in spite of the
tremely challenging due to their similar polarities. By using statistical reaction, there is some control over the substitu-
the conditions of Achelle et al. without an additional cop- tion pattern. In earlier studies we observed that the fluorine
per co-catalyst, the formation of the diacetylene was no atoms at the para positions are substituted first. Analyzing
longer observed and thus these reaction conditions were ex- the 19F NMR spectra of the entire library corroborates this
clusively considered. Subsequent column chromatography finding. In the library 1L with 1L15 as the lowest-molecu-
provided the porphyrin systems in reasonable yields ranging lar-weight member (10895 amu), all 12 fluorine atoms at
from 35 to 60% (see Table 2).
the para positions have been substituted.
These oligoporphyrin systems with various numbers of
For the peripheral functionalization of the porphyrin
peripheral pentafluorophenyl groups present
a large pentamer 2, similar conditions were applied, but with an
number of fluorines that can be substituted in SNAr reac- even larger excess of the nucleophile. By exposing 2 to
tions and are thus ideally suited as precursors of molecular 300 equiv. of both the thiol 16 and K2CO3 in DMF at 90 °C
libraries. As the degree of substitution and also the substi- for 24 h followed by similar work-up to that described
tution pattern are not uniform in this peripheral function- above for the library 1Lx, the library 2Lx was obtained. As
alization process, these precursors are the last structurally detailed in Table 4, 35–43 side-chains were introduced into
perfectly defined molecular building blocks in the synthesis the porphyrin pentamer 2 with the most abundant member
of the libraries. All four precursors were thus characterized being 2L40 (22454 amu).
1
as well as possible by H and 19F NMR spectroscopy and
Similarly to the observation made for 1Lx, 19F NMR
HRMS. Elemental analyses of these compounds were not analysis revealed the complete substitution of all the para-
performed because the highly fluorinated compounds fluorine substituents for all members of the library 2Lx,
caused severe damage to the GC analyzer column.
which points to the increased reactivity of this position.
The considerably higher number of substituted fluorine
atoms in the case of 2Lx compared with 1Lx has mainly
been attributed to the higher concentration of the nucleo-
phile during its synthesis. However, in the planar and more
Molecule Libraries
To obtain libraries of high-mass molecules, we focused extended structure of 2, the fluorine atoms are farther away
on the oligoporphyrin systems 1B and 2, both presenting from each other. Therefore the substitution seems to be eas-
60 fluorine atoms as potential substitution positions for ier in 2 than in 1B.
6
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
Fluoroalkyl-Functionalized Oligoporphyrin Systems
Table 3. Nucleophilic aromatic substitution reaction of porphyrin tetramer 1B to give porphyrin library 1Lx with x being the number of
alkylthiol substituents that have replaced fluorine atoms.
1Lx
x (number of C10H6F17S units) Number of F atoms (= 60 – x)
Mass [g/mol]
Calcd. mass [g/mol] Rel. intensity [%]
1L15
1L16
1L17
1L18
1L19
1L20
1L21
1L22
15
16
17
18
19
20
21
22
45
44
43
42
41
40
39
38
10895
11288
11785
12230
12668
13153
13620
14073
10790
11250
11711
12171
12631
13091
13551
14012
8
54
94
100
68
38
17
5
[a] The library members have the elemental formula C185H48F20–xN16Zn4[S(CH2)2C8F17]x in which x = 15–22 and the most abundant
member, 1L18, has x = 18 (12230 g/mol). Reagents and conditions: a) 120 equiv. 1H,1H,2H,2H-perfluorodecanethiol (16), 120 equiv.
K2CO3, DMF, 90 °C, 18 h.
The compositions of both libraries were studied by shows the spectrum of library 2Lx in the mass range be-
MALDI-TOF mass spectrometry. Figure 3 shows the mass tween 19000 and 24000 g/mol. Interestingly, we observed in-
spectrum of 1Lx with masses between 10000 and 15000 g/ creased ionization in the MALDI-TOF MS for 2Lx com-
mol. Eye-catching is the regular periodic mass difference pared with 1Lx, as its ion signal is about 10 times higher
between adjacent peaks, which corresponds roughly to the integrated over the same number of shots. Better ionization
mass difference between an additional alkylthiolate sub- properties have previously been observed for metal-free
stituting
a
fluorine atom of the porphyrin core porphyrins in studies on single porphyrins as central cores
(460Ϯ10 amu). To label the peaks the strongest signal was for libraries. We thus attribute this difference to the differ-
selected. Variations from the theoretical values are due to ence in the coordination state of the oligoporphyrins. A
the natural isotopic distribution. Another aspect that leads similar systematic separation of the peaks by the difference
to broadening of the peaks is the coexistence of signals due in mass between the fluorinated alkylthiol and the substi-
to [M]+ and [M + H]+ in the spectra. The specific mass tuted fluorine atom is observed. However, the peaks are
peaks correspond to different numbers of perfluoroalkyl even broader in the case of 2Lx. This broadening of the
substituents on the fluorinated porphyrin cores. The precise peaks can be explained by the two-fold higher masses of
composition of the library determined by MALDI-TOF the components of library 2Lx compared with those of
MS is listed in Table 3 above.
1Lx. The highest signal was obtained for 2L40 with x = 40.
Exposing the porphyrin pentamer 2 to a higher concen- A complete list of the components of the library is given in
tration of alkylthiol provided even higher masses. Figure 4 Table 4 above.
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
7

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
L. Felix, U. Sezer, M. Arndt, M. Mayor
FULL PAPER
Table 4. Nucleophilic aromatic substitution reaction of porphyrin pentamer 2 to give porphyrin library 2Lx with x being the number of
alkylthiol substituents that have replaced a fluorione atom.
2Lx
x (number of C10H6F17S units) Number of F atoms (= 60 – x)
Mass [g/mol]
Calcd. mass [g/mol] Rel. intensity [%]
2L35
2L36
2L37
2L38
2L39
2L40
2L41
2L42
2L43
35
36
37
38
39
40
41
42
43
25
24
23
22
21
20
19
18
17
20121
20588
21061
21514
21983
22454
22931
23404
23878
20041
20501
20961
21421
21881
22341
22801
23261
23722
6
26
50
78
89
100
62
24
5
[a] The members of the library have the elemental formula C204H66F60–xN20[S(CH2)2C8F17]x in which x = 35–43 and with the most
abundant member being for x = 40 (12230 g/mol). Reagents and conditions: a) 300 equiv. 1H,1H,2H,2H-perfluorodecanethiol (16),
300 equiv. K2CO3, DMF, 90 °C, 24 h.
Figure 3. MALDI-TOF analysis of library 1Lx bearing 15–22 per-
fluoroalkyl side-chains (x = 15–22). The masses range between
10000 and 15000 g/mol and a maximum is observed for x = 18
(12228 g/mol). The spectrum was calibrated by using CsI3 clus-
ters.[34] DCTB {trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propen-
ylidene]malononitrile} was used as matrix.[35] The spectrum was
integrated over 2000 shots.
Figure 4. MALDI-TOF analysis library 2Lx bearing 35–43 per-
fluoroalkyl side-chains (x = 35–43). The mass range is between
19000 and 24000 g/mol and a maximum is observed for x = 40
(22263 g/mol). The spectrum was calibrated by using CsI3 clus-
ters.[34] DCTB was used as matrix.[35] The number of counts was
obtained by integration over 2000 shots.
8
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
Fluoroalkyl-Functionalized Oligoporphyrin Systems
Based on the characterization of the libraries 1Lx and
Another difference lies in the fragmentation behavior of
2Lx, the ability of their members to provide molecular the two molecular libraries. Thermal decomposition causes
beams upon excitation was investigated.
saturation in both cases, but the decay of 1Lx is faster than
for 2Lx. This is consistent with the observation that relax-
ation rates are strongly correlated to molecular size.[39] The
members of the library 2Lx possess about twice as many
energy vibrational relaxation channels as those of 1Lx.
Desorption Studies
To test whether the libraries 1Lx and 2Lx fulfil the
requirements for future matter-wave experiments, we car-
ried out additional laser desorption and post-ionization
studies. We are interested in libraries that can be volatilized
at low velocity and post-ionized without major fragmenta-
tion. For this purpose, a Nd:YAG laser beam (λ = 355 nm,
τ = 4 ns) was focused to a spot diameter of 350 μm and
directed onto the target plate at an angle of 30°. The sample
was prepared by allowing a droplet of a library solution to
dry on the substrate. Either 2.5 mg of 1Lx dissolved in
1.5 mL diethyl ether or 7 mg of 2Lx in 1.5 mL TBME was
used. An excimer laser (λ = 157.6 nm, Eph = 7.89 eV) was
used for post-ionization of the neutrally desorbed mol-
ecules, which were then extracted into a linear TOF-MS.
A comparison of Figure 5 (a) (1Lx) with Figure 5 (b)
(2Lx) shows two major differences. The saturation intensity
of library 2Lx exceeds that of library 1Lx by almost a fac-
tor of two. The faster rise of the 1Lx desorption curve indi-
Conclusions
We have presented a modular synthetic approach to ex-
panding our concept of molecular libraries to larger molec-
ular masses. Four different porphyrin oligomers have been
explored, the two most massive ones as “nuclei” for the
synthesis of complex molecular libraries. By varying the
synthetic conditions different numbers of fluorine atoms
were substituted by fluorinated alkylthiolates leading to a
broad mass range.
In the case of 2Lx, up to 43 fluorinated alkylsulfanyl
side-chains were introduced, corresponding to a mass of
about 23.8 kg/mol. Analysis by MALDI-TOF mass spec-
trometry revealed well-separated individual members of the
library with a well-defined mass distribution for both librar-
ies 1Lx and 2Lx. Preliminary desorption studies indicate
that neutral and intact molecules can be desorbed by using
short-pulse UV laser light. Ionization of the desorbed mem-
bers by 157.6 nm radiation enabled their subsequent detec-
tion by mass spectrometry. A most promising intensity win-
dow for the desorption laser has been identified that allows
us to launch neutral particles without major thermal de-
composition. To the best of our knowledge, oligoporphyrins
with highly fluorinated alkylsulfanyl chains are the most
massive particles reported to date that are sufficiently stable
and volatile to be compatible with pulsed laser evaporation
and post-ionization.
cates
a lower evaporation enthalpy with respect to
2Lx.[10,36] This is consistent with a lower polarizability and
smaller van der Waals interactions in the components of li-
brary 1Lx in comparison with 2Lx. 2Lx has on average
twice as many fluoroalkylsulfanyl side-chains and a more
polarizable core than 1Lx.[37,38] Also, the more planar
shape of the core structure of 2Lx compared with the rather
spherical shape of 1Lx might play a role.
The concept presented herein is not limited to the mass
range of 24 kg/mol. The modularity of the core synthesis
and the ease of peripheral functionalization encourage fur-
ther exploration of the mass limit for volatile particles,
either by assembling even larger porphyrin oligomers as
core structures or by introducing longer and/or branched
fluorinated alkylsulfanyl chains.
Experimental Section
General: All commercially available starting materials were reagent
grade and used as received from Sigma–Aldrich, Acros, Apollo
Scientific, Alfa Aesar, and Fluorochem, and used as purchased.
Dry solvents were purchased from Sigma–Aldrich, stored over mo-
lecular sieves (4 Å), and handled under argon. The solvents for
column chromatography and extraction were of technical grade.
Column chromatography purifications were performed on silica gel
Figure 5. Variation of the desorption laser power at constant post-
ionization laser intensity. a) Data for the molecular library 1Lx.
b) Data for the molecular library 2Lx. In comparison with the data
for the lower-mass tetramer shown in (a), the pentamer reaches
saturation at a higher desorption intensity. This indicates its higher
enthalpy of volatilization as well as its higher thermal stability in
comparison with the molecular library 1Lx. Different symbols (tri-
angles, circles and squares) represent different numbers of per-
fluoroalkylated chains. The solid lines are guides to the eye. Each
data point is a sum of 90 laser shots.
1
60 (particle size 0.040–0.063 mm) from Silicycle. H, 19F, and 13C
NMR spectra were recorded with Bruker DMX 400 (1H: 400 MHz)
or DRX 500 or 600 MHz instruments (1H: 500 or 600 MHz) at
298 K. Not all the 13C NMR spectra were recorded because fluor-
ine coupling decreases signal intensity tremendously (see the Sup-
porting Information). Deuteriated solvents were purchased from
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
9

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
L. Felix, U. Sezer, M. Arndt, M. Mayor
FULL PAPER
Cambridge Isotope Laboratories. UV/Vis spectra were recorded
with a Shimadzu UV-1800 spectrophotometer. MALDI-TOF mass
spectra were recorded with a Bruker Microflex LRF spectrometer
and were calibrated by using CsI3 clusters.[34] DCTB {trans-2-[3-
(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile} was
used as matrix if needed.[35] High-resolution mass spectra were re-
corded with a Bruker solariX spectrometer (ESI/MALDI-FTICR-
MS). Electron impact (EI) mass spectra were recorded with a Fin-
nigan MAT 95Q spectrometer. Elemental analyses were measured
with an Elementar Vario Micro Cube instrument.
The reaction mixture was stirred for 24 h at room temperature and
then washed with water. The solvent was evaporated under reduced
pressure to obtain the zinc complex 14 quantitatively as a purple
solid (542 mg, 0.56 mmol, 966.0 g/mol). 1H NMR (400 MHz,
3
CDCl3): δ = 0.64 (s, 9 H, TMS): 8.92 (s, 4 H, Ar-H), 8.96 (d, JHH
3
= 4.7 Hz, 2 H, Ar-H), 9.88 (d, JHH = 4.7 Hz, 2 H, Ar-H) ppm.
19F NMR (376 MHz, CDCl3): δ = –136.9 (m, 3 F, Ar-F), –152.1
(m, 6 F, Ar-F), –161.7 (m, 6 F, Ar-F) ppm. MS (MALDI-TOF):
m/z (%) = 966.8 (100) [M]+, 967.8 (89), 968.7 (98), 969.6 (80), 970.6
(82), 971.6 (58), 972.6 (20). HRMS (MALDI/ESI): calcd. for
C43H17F15N4SiZn 966.0269; found 966.0269.
5,10,15-Tris(pentafluorophenyl)-20-(2-trimethylsilylethynyl)por-
phyrin (5): A solution of pentafluorobenzaldehyde (8, 2.74 mL,
22 mmol, 2.0 equiv.), 3-(trimethylsilyl)-2-propynal (7, 1.84 mL,
12 mmol, 1.1 equiv.), and 5-(pentafluorophenyl)dipyrromethane (6,
6.9 g, 22 mmol, 2.0 equiv.) in chloroform (2.5 L; high dilution) was
degassed under a constant stream of argon for 45 min and then
[5,10,15-Tris(pentafluorophenyl)-20-(ethynyl)porphyrinato]zinc (15):
Zinc complex 14 (250 mg, 0.26 mmol, 1.0 equiv.) was dissolved in
wet dichloromethane (100 mL) and TBAF (1 m in THF, 516 mL,
0.52 mmol, 2.0 equiv.) was added dropwise. The reaction mixture
was stirred for 30 min at room temperature. Then methanol
treated with BF3·O(Et)2 (2.5 m in CHCl3, 2.92 mL, 0.66 equiv.). (100 mL) was added and the solvent removed under reduced pres-
The reaction was stirred at room temperature for 18 h. DDQ
(7.68 g, 1.5 mmol) was added and the reaction mixture stirred for
another 2 h at room temperature. After filtration through silica the
solvent was removed under reduced pressure. The remaining solid
was purified three times by column chromatography (silica gel; cy-
clohexane/dichloromethane, 5:1) to obtain 5 as a dark-purple solid
(1.52 g, 11.1 mol, 904.11 g/mol, 15%). UV/Vis (CHCl3): λ = 415,
sure. The resulting solid was dissolved in dichloromethane (50 mL)
and washed with water. The combined organic layers were dried
with anhydrous Na2SO4 and the solvent was removed under re-
duced pressure. The resulting solid was purified by column
chromatography (silica gel; cyclohexane/acetone, 2:1) to yield the
zinc complex 15 as a violet solid in quantitative yield (229 mg,
0.26 mmol, 895.9 g/mol). UV/Vis (CHCl3): λ = 322, 432, 565,
1
1
508, 536, 584 nm. H NMR (400 MHz, CDCl3): δ = –2.55 (br. s, 2
603 nm. H NMR (400 MHz, CDCl3): δ = 3.65 (s, 1 H, CH), 8.88
3
3
3
H, NH), 0.65 (s, 9 H, TMS), 8.85 (s, 4 H, Ar-H), 8.88 (d, JHH
=
(d, JHH = 4.6 Hz, 2 H, Ar-H), 8.94 (s, 4 H, Ar-H), 9.51 (d, JHH
4.8 Hz, 2 H, Ar-H), 9.80 (d, JHH = 4.8 Hz, 2 H, Ar-H) ppm. 19F
= 4.7 Hz, 2 H, Ar-H) ppm. 19F NMR (376 MHz, CDCl3): δ =
3
NMR (376 MHz, CDCl3): δ = –136.5 (m, 2 F, Ar-F), –136.6 (m, 4 –136.9 (m, 3 F, Ar-F), –152.0 (m, 6 F, Ar-F), –161.8 (m, 6 F, Ar-
F, Ar-F), –151.5 (m, 3 F, Ar-F), –161.5 (m, 6 F, Ar-F) ppm. 13C
NMR (126 MHz, CDCl3): δ = 0.68 (s, 3 C, TMS), 102.65 (s, 1 C,
Cq), 103.36 (s, 1 C, Cq), 103.69 (s, 2 C, Cq), 104.55 (s, 1 C, Cq),
105.56 (s, 1 C, Cq), 115.36 (s, 1 C, Cq), 115.59 (s, 2 C, Cq), 130.25
(m, 2 C, Ct), 130.90 (m, 2 C, Ct), 130.94 (m, 2 C, Ct), 132.40 (m,
2 C, Ct), 137.55 (s, 2 C, Ct), 137.57 (s, 4 C, Ct), 146.47 (m, 4 C,
Ct), 146.50 (m, 2 C, Ct) ppm. MS (MALDI-TOF): m/z (%) = 904.2
(100) [M]+, 905.2 (82), 906.1 (27), 907.1 (10). HRMS (MALDI/
ESI): calcd. for C43H19F15N4Si 904.1134; found 904.1136.
C43H19F15N4Si (904.11): calcd. C 57.09, H 2.12, N 6.19; found C
57.45, H 2.49, N6.62.
F) ppm. MS (MALDI-TOF): m/z (%) = 893.8 (100) [M]+, 894.8
(31), 895.7 (55), 896.7 (22), 897.7 (31), 898.7 (6). HRMS (MALDI/
ESI): calcd. for C40H9F15N4Zn 893.9874; found 893.9874.
[5,10,15-Tris(pentafluorophenyl)-20-(ethynylphenyl)porphyrinato]-
zinc Dimer (3B): Zinc complex 15 (30 mg, 33.5 μmol, 1 equiv.) and
1,4-diiodobenzene (9, 3.32 mg, 10 μmol, 0.3 equiv.) were dissolved
in THF (2 mL) in an oven-dried two-necked flask. The solution
was degassed under a constant stream of argon for 20 min. Then
tris(dibenzylideneacetone)dipalladium(0) (9.2 mg, 10 μmol,
0.3 equiv.) and triphenylarsine (16 mg, 0.05 mmol, 1.5 equiv.) were
added and the reaction started by the addition of triethylamine
(2 mL). The reaction mixture was heated at reflux for 18 h, when
TLC showed full conversion of the starting materials. After cooling
to room temperature tert-butyl methyl ether was added and the
organic phase was washed with aq. satd. Na2HCO3, water, and
brine. The combined organic phases were dried with anhydrous
Na2SO4 and the solvent was removed under reduced pressure. The
resulting residue was purified by column chromatography (silica
gel; cyclohexane/acetone, 3:1) to obtain the dimer 3B as a dark-
green solid (35 mg, 18.8 μmol, 1865.87 g/mol, 56 %). 1H NMR
(400 MHz, CDCl3): δ = 8.55 (s, 4 H, Ar-H), 9.19 (m, 8 H, Ar-H),
5,10,15-Tris(pentafluorophenyl)-20-(ethynyl)porphyrin (13): Por-
phyrin (5, 100 mg, 0.11 mmol, 1.0 equiv.) was dissolved in wet
dichloromethane (50 mL) and TBAF (1 m in THF, 220 μL,
0.22 mmol, 2.0 equiv.) was added dropwise. The reaction mixture
was stirred for 30 min at room temperature. Then methanol
(50 mL) was added and the solvent removed under reduced pres-
sure. The resulting solid was dissolved in dichloromethane (50 mL)
and washed with water and brine. The combined organic layers
were dried with anhydrous Na2SO4 and the solvent was removed
under reduced pressure. The resulting solid was purified by column
chromatography (silica gel; cyclohexane/acetone, 2:1) to yield the
3
3
9.31 (d, JHH = 4.6 Hz, 4 H, Ar-H), 10.10 (d, JHH = 4.6 Hz, 4 H,
porphyrin 13 as a violet solid in quantitative yield (92 mg, Ar-H) ppm. 19F NMR (376 MHz, CDCl3): δ = –140.0 (m, 6 F, Ar-
1
0.11 mmol, 832.5 g/mol). H NMR (400 MHz, CDCl3): δ = –2.65
F), –156.3 (m, 12 F, Ar-F), –165.1 (m, 12 F, Ar-F) ppm. HRMS
(MALDI/ESI): calcd. for C86H20F30N8Zn2 1861.9909; found
(br. s, 2 H, NH), 4.17 (s, 1 H, CH), 8.85 (s, 4 H, Ar-H), 8.87 (m, 2
H, Ar-H), 9.80 (m, 2 H, Ar-H) ppm. 19F NMR (376 MHz, CDCl3): 1861.9919.
δ = –136.6 (m, 3 F, Ar-F), –151.4 (m, 6 F, Ar-F), –161.4 (m, 6 F,
[5,10,15-Tris(pentafluorophenyl)-20-(ethynylphenyl)porphyrinato]-
Ar-F) ppm. MS (MALDI-TOF): m/z (%) = 832.2 (100) [M]+, 833.2
(94), 834.1 (34), 835.1 (17), 836.1 (6). HRMS (MALDI/ESI): calcd.
for C40H11F15N4 832.0739; found 832.0736.
zinc Trimer (4B): The reaction was performed under similar condi-
tions to those used for the synthesis of dimer 3B. Zinc complex 15
(50 mg, 51.6 μmol, 1 equiv.) and 1,3,5-triiodobenzene (10, 4.7 mg,
10 μmol, 0.2 equiv.) were used with 0.45 equiv. catalyst and
3.0 equiv. triphenylarsine in THF/triethylamine (5 mL, 1:1). Purifi-
cation was performed by column chromatography (silica gel; cyclo-
hexane/ethyl acetate, 4:1) to obtain the trimer 4B as a dark-green
[5,10,15-Tris(pentafluorophenyl)-20-(2-trimethylsilylethynyl)por-
phyrinato]zinc (14): A solution of zinc acetate (594 mg, 0.13 mmol,
3.2 equiv.) in methanol (25 mL) was added to a solution of por-
phyrin 5 (507 mg, 0.56 mmol, 1.0 equiv.) in chloroform (110 mL).
10
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
Fluoroalkyl-Functionalized Oligoporphyrin Systems
solid (17 mg, 6 μmol, 2753.96 g/mol, 35%). 1H NMR (400 MHz, aqueous phase was extracted with TBME (3ϫ 20 mL). The com-
CDCl3): δ = 9.15 (m, 3 H, Ar-H), 9.22 (m, 12 H, Ar-H), 9.38 (m,
6 H, Ar-H), 10.31 (m, 6 H, Ar-H) ppm. 19F NMR (376 MHz,
CDCl3): δ = –139.9 (m, 9 F, Ar-F), –156.3 (m, 18 F, Ar-F), –165.0
(m, 18 F, Ar-F) ppm. MS (MALDI-TOF): m/z (%) = 2753.61 (100)
bined organic phases were washed three times with water and brine,
and dried with anhydrous sodium sulfate. The solvent was removed
under reduced pressure. The resulting brown residue was dissolved
again in TBME (10 mL) and filtered through a plug of silica to
[M]+, 2775.18 (30), 2781.79 (32), 2783.93 (35). HRMS (MALDI/ remove dithiol residues. The solvent was removed under reduced
ESI): calcd. for C126H27F45N12Zn3 2753.9637; found 2754.9710.
pressure and the resulting library 2Lx (198 mg) analyzed by
MALDI-TOF mass spectrometry. MS (MALDI-TOF): m/z (%) =
23878 (5), 23404 (24), 22931 (62), 22454 (100), 21983 (89), 21514
(78), 21061 (50), 20588 (26), 20121 (6).
[5,10,15-Tris(pentafluorophenyl)-20-(ethynylphenyl)porphyrinato]-
zinc Tetramer (1B): The reaction was performed under similar con-
ditions to those used for the synthesis of dimer 3B. Porphyrin 15
(100 mg, 112 μmol, 1 equiv.) and tetrakis(4-iodophenyl)methane
(11, 19 mg, 22 μmol, 0.2 equiv.) were used with 0.6 equiv. catalyst
and 3.0 equiv. triphenylarsine in THF/triethylamine (12 mL, 1:1).
After purification by column chromatography (silica gel; cyclohex-
ane/acetone, 3:1), the tetramer 1B was obtained as a dark-green
Supporting Information (see footnote on the first page of this arti-
cle): 1H, 19F, and 13C NMR spectra and determination of com-
pounds 1B, 2, 3B, 4B, 5, and 13–15 (if available), the synthetic
procedures for 6, 11, and 12,which are small variations of reported
procedures.
1
solid (56 mg, 14 μmol, 3895.99 g/mol, 51%). H NMR (400 MHz,
CDCl3): δ = –2.55 (br. s, 2 H, NH), 0.65 (s, 9 H, TMS), 8.85 (s, 4
3
3
H, Ar-H), 8.88 (d, JHH = 4.8 Hz, 2 H, Ar-H), 9.80 (d, JHH
=
Acknowledgments
4.8 Hz, 2 H, Ar-H) ppm. 19F NMR (376 MHz, CDCl3): δ = –136.6
(m, 12 F, Ar-F), –151.2 (m, 24 F, Ar-F), –161.5 (m, 24 F, Ar-
The authors acknowledge financial support by the Swiss National
Science Foundation, NCCR “Nanoscale Science”, and the Swiss
Nanoscience Institute (SNI). The groups in Basel and Vienna were
supported by the FWF programs Wittgenstein (Z149-N16) and the
doctoral programm CoQuS (grant W1210-3), and the European
Commission through the (NANOQUESTFIT project 304886). The
authors thank Michel Rickhaus for the art work for the table of
contents.
F) ppm. HRMS (MALDI/ESI): calcd. for
3889.0528; found 3889.0523.
C185H48F60N16Zn4
5,10,15-Tris(pentafluorophenyl)-20-(ethynylphenyl)porphyrin Penta-
mer (2): The reaction was performed under similar conditions to
those used for the synthesis of dimer 3B. Porphyrin 13 (164 mg,
197 μmol, 1 equiv.) and porphyrin 12 (44 mg, 39.3 μmol, 0.2 equiv.)
were used with 0.6 equiv. catalyst and 3 equiv. triphenylarsine in
THF/triethylamine (20 mL, 1:1). Purification was carried out by
column chromatography (silica gel; cyclohexane/acetone, 3:1) to
give the pentamer 2 as a dark-green solid (93 mg, 39 μmol,
[1] F. Hasselbach, Rep. Prog. Phys. 2010, 73, 016101.
[2] S. W. H. Rauch, Meas. Sci. Technol. 2001, 12, 355.
[3] A. D. Cronin, J. Schmiedmayer, D. E. Pritchard, Rev. Mod.
Phys. 2009, 81, 1051–1129.
[4] T. Juffmann, H. Ulbricht, M. Arndt, Rep. Prog. Phys. 2013, 76,
086402.
1
3936.81 g/mol, 60%). H NMR (400 MHz, CDCl3): δ = –2.47 (br.
3
s, 2 H, NH), –2.35 (br. s, 8 H, NH), 8.55 (d, JHH = 7.8 Hz, 8 H,
3
Ar-H), 8.61 (d, JHH = 7.8 Hz, 8 H, Ar-H), 8.85 (m, 16 H, Ar-H),
8.98 (m, 8 H, Ar-H), 9.21 (m, 8 H, Ar-H), 10.08 (m, 8 H, Ar-
H) ppm. 19F NMR (376 MHz, CDCl3): δ = –136.6 (m, 12 F, Ar- [5] K. Hornberger, S. Gerlich, P. Haslinger, S. Nimmrichter, M.
Arndt, Rev. Mod. Phys. 2012, 84, 157–173.
F), –151.4 (m, 24 F, Ar-F), –161.4 (m, 24 F, Ar-F) ppm. HRMS
[6] M. Arndt, O. Nairz, J. Vos-Andreae, C. Keller, G.
van der Zouw, A. Zeilinger, Nature 1999, 401, 680–682.
[7] B. Brezger, L. Hackermüller, S. Uttenthaler, J. Petschinka, M.
Arndt, A. Zeilinger, Phys. Rev. Lett. 2002, 88, 100404.
[8] B. Brezger, L. Hackermüller, S. Uttenthaler, J. Petschinka, M.
Arndt, A. Zeilinger, Phys. Rev. Lett. 2002, 88, 100404.
[9] L. Hackermüller, S. Uttenthaler, K. Hornberger, E. Reiger, B.
Brezger, A. Zeilinger, M. Arndt, Phys. Rev. Lett. 2003, 91,
090408.
[10] J. Tüxen, S. Eibenberger, S. Gerlich, M. Arndt, M. Mayor, Eur.
J. Org. Chem. 2011, 4823–4833.
[11] S. Gerlich, S. Eibenberger, M. Tomandl, S. Nimmrichter, K.
Hornberger, P. J. Fagan, J. Tüxen, M. Mayor, M. Arndt, Nat.
Commun. 2011, 2, 263.
(MALDI/ESI): calcd. for
3934.4847.
C204H66F60N20 3934.4816; found
Porphyrin Tetramer Library 1Lx: The porphyrin tetramer 1B
(25 mg, 6.42 μmol, 1 equiv.) was dissolved in DMF (10 mL) and
1H,1H,2H,2H-perfluorodecanethiol (16, 220 μL, 770 μmol,
120 equiv.) was added. After the addition of potassium carbonate
(106 mg, 770 μmol, 120 equiv.) in two portions the reaction mixture
was heated at 90 °C for 18 h in an oil bath. Water was added to
the hot reaction mixture and the aqueous phase separated. The
aqueous phase was extracted with TBME (3ϫ 20 mL). The com-
bined organic phases were washed three times with water and brine,
and dried with anhydrous sodium sulfate. The solvent was removed
under reduced pressure. The resulting brown residue was dissolved
again in TBME (10 mL) and filtered through silica gel to remove
dithiol residues. The solvent was removed under reduced pressure
and the resulting library 1Lx (258 mg) analyzed by MALDI-TOF
mass spectrometry. MS (MALDI-TOF): m/z (%) = 14073 (5),
13620 (17), 13153 (38), 12668 (68), 12230 (100), 11785 (94), 11288
(54), 10895 (8).
[12] S. Eibenberger, S. Gerlich, M. Arndt, M. Mayor, J. Tüxen,
Phys. Chem. Chem. Phys. 2013, 15, 14696–14700.
[13] P. Schmid, F. Stöhr, M. Arndt, J. Tüxen, M. Mayor, J. Am.
Soc. Mass Spectrom. 2013, 24, 602–608.
[14] N. L. Stock, D. A. Ellis, L. Deleebeeck, D. C. G. Muir, S. A.
Mabury, Environ. Sci. Technol. 2004, 38, 1693–1699.
[15] P. J. Krusic, A. A. Marchione, F. Davidson, M. A. Kaiser, C.-
P. C. Kao, R. E. Richardson, M. Botelho, R. L. Waterland,
R. C. Buck, J. Phys. Chem. A 2005, 109, 6232–6241.
[16] G. Gil-Ramírez, S. D. Karlen, A. Shundo, K. Porfyrakis, Y. Ito,
G. A. D. Briggs, J. J. L. Morton, H. L. Anderson, Org. Lett.
2010, 12, 3544–3547.
[17] S. A. Odom, S. Webster, L. A. Padilha, D. Peceli, H. Hu, G.
Nootz, S.-J. Chung, S. Ohira, J. D. Matichak, O. V. Przhonska,
E. W. Van Stryland, J.-L. Brédas, H. L. Anderson, M. R. Wasi-
lewski, S. R. Marder, J. Am. Chem. Soc. 2009, 131, 7510–7511.
Porphyrin Pentamer Library 2Lx: The porphyrin tetramer 2 (21 mg,
5.33 μmol, 1 equiv.) was dissolved in DMSO (10 mL) and
1H,1H,2H,2H-perfluorodecanethiol (16, 345 μL, 1.20 mmol,
225 equiv.) was added. After the addition of potassium carbonate
(170 mg, 1.20 mmol, 225 equiv.) in two portions the reaction mix-
ture was heated at 90 °C for 18 h in an oil bath. Water was added
to the hot reaction mixture and the aqueous phase separated. The
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
11

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
L. Felix, U. Sezer, M. Arndt, M. Mayor
FULL PAPER
[18]
[28] M. Fathalla, J. Jayawickramarajah, Eur. J. Org. Chem. 2009,
6095–6099.
[29] C.-H. Lee, J. S. Lindsey, Tetrahedron 1994, 50, 11427–11440.
[30] J. S. Lindsey, S. Prathapan, T. E. Johnson, R. W. Wagner, Tetra-
hedron 1994, 50, 8941–8968.
[31] I. Aujard, J.-P. Baltaze, J.-B. Baudin, E. Cogné, F. Ferrage, L.
Jullien, É. Perez, V. Prévost, L. M. Qian, O. Ruel, J. Am. Chem.
Soc. 2001, 123, 8177–8188.
[32] J. L. Shaw, S. A. Garrison, E. A. Alemán, C. J. Ziegler, D. A.
Modarelli, J. Org. Chem. 2004, 69, 7423–7427.
[33] M. Urbani, J. Iehl, I. Osinska, R. Louis, M. Holler, J. Nieren-
garten, Eur. J. Org. Chem. 2009, 3715–3725.
S. A. Odom, R. F. Kelley, S. Ohira, T. R. Ensley, C. Huang,
L. A. Padilha, S. Webster, V. Coropceanu, S. Barlow, D. J.
Hagan, A. D. Kachkovski, S. Barlow, J.-L.Brédas, H. L. An-
derson, D. J. Hagan, E. W. Van Stryland, S. R. Marder, J. Phys.
Chem. A 2009, 113, 10826–10832.
M. Drobizhev, Y. Stepanenko, Y. Dzenis, A. Karotki, A. Re-
bane, P. N. Taylor, H. L. Anderson, J. Phys. Chem. B 2005, 109,
7223–7236.
J. L. Retsek, C. J. Medforth, D. J. Nurco, S. Gentemann, V. S.
Chirvony, K. M. Smith, D. Holten, J. Phys. Chem. B 2001, 105,
6396–6411.
M. Drobizhev, F. Meng, A. Rebane, Y. Stepanenko, E. Nickel,
C. W. Spangler, J. Phys. Chem. B 2006, 110, 9802–9814.
[19]
[20]
[21]
[22]
[34] X. Lou, J. L. J. van Dongen, E. W. Meijer, J. Am. Soc. Mass
Spectrom. 2010, 21, 1223–1226.
M. Pawlicki, H. A. Collins, R. G. Denning, H. L. Anderson,
Angew. Chem. Int. Ed. 2009, 48, 3244–3266; Angew. Chem.
2009, 121, 3292.
[35] J. D. Winter, G. Deshayes, F. Boon, O. Coulembier, P. Dubois,
P. Gerbaux, J. Mass Spectrom. 2011, 46, 237–246.
[36] K. Dreisewerd, M. Schürenberg, M. Karas, F. Hillenkamp, Int.
J. Mass Spectrom. Ion Process 1995, 141, 127–148.
[37] S. Eibenberger, S. Gerlich, M. Arndt, J. Tüxen, M. Mayor, New
J. Phys. 2011, 13, 043033.
[38] S. Deachapunya, A. Stefanov, M. Berninger, H. Ulbricht, E.
Reiger, N. L. Doltsinis, M. Arndt, J. Chem. Phys. 2007, 126,
164304.
[23] S. Achelle, P. Couleaud, P. Baldeck, M.-P. Teulade-Fichou, P.
Maillard, Eur. J. Org. Chem. 2011, 1271–1279.
[24] R. Chinchilla, C. Nájera, Chem. Rev. 2007, 107, 874–922.
[25] T. Ljungdahl, T. Bennur, A. Dallas, H. Emtenäs, J. Mårtensson,
Organometallics 2008, 27, 2490–2498.
[26] R. W. Wagner, T. E. Johnson, F. Li, J. S. Lindsey, J. Org. Chem.
1995, 60, 5266–5273.
[27] A. Jiblaoui, C. Baudequin, V. Chaleix, G. Ducourthial, F. Lou-
radour, Y. Ramondenc, V. Sol, S. Leroy-Lhez, Tetrahedron
2013, 69, 5098–5103.
[39] Y. Hu, B. Hadas, M. Davidovitz, B. Balta, C. Lifshitz, J. Phys.
Chem. A 2003, 107, 6507–6514.
Received: June 26, 2014
Published Online: ᭿
12
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O42816
/KAP1
Date: 10-09-14 18:03:39
Pages: 13
Fluoroalkyl-Functionalized Oligoporphyrin Systems
Fluorinated Oligoporphyrins
Massive but volatile molecules have been
obtained by functionalizing the periphery
of oligoporphyrins with highly fluorinated
alkyl chains. The statistical nature of the
reaction gives libraries consisting of mol-
ecules with well-defined masses but small
structural diversity. Laser desorption and
post-ionization studies demonstrated the
potential of these libraries as sources of
heavy particles.
L. Felix, U. Sezer, M. Arndt,
M. Mayor* ..................................... 1–13
Synthesis of Highly Fluoroalkyl-Func-
tionalized Oligoporphyrin Systems
Keywords: Chemical libraries / Porphyr-
inoids / Fluorine / Aromatic substitution /
Mass spectrometry
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
13