Oligoether-strapped meso-pyrimidinylporphyrins

Article abstract of DOI:10.1016/j.tetlet.2012.02.116

Bis(oligoether-strapped) zinc(II)-meso-pyrimidinylporphyrins were readily synthesized via nucleophilic aromatic substitution reactions of biscathechol-substituted tri- or tetraethylene glycol straps on the upper and lower faces of a Zn(II)-A₂B<

Full text of DOI:10.1016/j.tetlet.2012.02.116

Tetrahedron Letters 53 (2012) 2406–2409
Contents lists available at SciVerse ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Oligoether-strapped meso-pyrimidinylporphyrins
Thien H. Ngo a,b, , Klaudia A. Nitychoruk a, Dieter Lentz c, Tomasz Rzymowski a, Wim Dehaen a,
⇑
⇑
,
Wouter Maes a,d
a Molecular Design and Synthesis, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
b Institut für Chemie und Biochemie–Organische Chemie, Freie Universität Berlin, Takustrasse 3, D-14195 Berlin, Germany
c Institut für Chemie und Biochemie–Anorganische Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, D-14195 Berlin, Germany
d Institute for Materials Research (IMO-IMOMEC), Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University, Universitaire Campus, Agoralaan 1–Building D,
B-3590 Diepenbeek, Belgium
a r t i c l e i n f o
a b s t r a c t
Article history:
Bis(oligoether-strapped) zinc(II)-meso-pyrimidinylporphyrins were readily synthesized via nucleophilic
aromatic substitution reactions of biscathechol-substituted tri- or tetraethylene glycol straps on the
upper and lower faces of a Zn(II)-A2B2-meso-dichloropyrimidinylporphyrin precursor. The crown ether-
like bridges surrounding the porphyrin core create peculiar cavities above and below the macrocyclic
plane with appealing features for supramolecular host–guest chemistry.
Received 27 January 2012
Revised 23 February 2012
Accepted 29 February 2012
Available online 7 March 2012
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Porphyrins
Dichloropyrimidines
Crown ethers
Nucleophilic aromatic substitution
Supramolecular receptors
Molecular recognition of anions and cations is an important
subfield within supramolecular chemistry due to the major role
that ions play in diverse domains such as bio(techno)logy, medi-
cine, and environmental research.1 Despite considerable number
of receptors already reported in the literature, the search for highly
selective and efficient ion-hosting molecules remains a hot topic.
Receptors combining high selectivity with a sensitive response,
for example via photophysical and electrochemical changes, are
of particular interest. To date, mainly crown ethers, podands, and
cryptands are used as molecular hosts for cations. A particular cat-
ion receptor type is based on porphyrinoid chromophores with ap-
pended crown ether(-like) receptor motifs.2 The appealing and
differentiating aspect of such receptors may lie in their particular
photophysical features. Complexation of cations by a crown ether
moiety in proximity of the active porphyrinoid center can cause
a photophysical response. This should allow easy monitoring of
the binding event by color and/or fluorescence intensity changes,
leading to the potential application in photochemical sensors.
In most previously reported porphyrin–crown receptors, the
crown ether moieties are located on the periphery of the porphyrin
ring.2 Only a few crown ether-bridged porphyrinoids have been
reported so far.3 In these molecules, the crown ether bridges direct
the complexation of guest species above and below the tetrapyrr-
olic plane, which can be expected to have a more direct influence
on the photophysical properties. Although the application poten-
tial of such materials is high, the main drawback of the reported
systems is their tedious synthesis. In these previous reports, two
different pathways were described to obtain crown ether-bridged
porphyrins. The first route starts with the synthesis of the porphy-
rin core, followed by linkage of the (mostly not commercially
available) crown ether moiety,3a–c,e whereas the second pathway
involved the preparation of an aldehyde-functionalized crown
ether employed directly in porphyrin synthesis.3d In both proce-
dures, the difficult synthesis of the tetrapyrrolic core and/or the
crown ether–porphyrin linkage has led to low overall yields.
Moreover, most of the above described systems consist of one
crown ether bridge only, allowing single cation capture at a time
only.3a,b,d,e Boitrel and coworkers were the first to report a bis
(cyclam-strapped) porphyrin with identical diaza-18-crown-6
ether moieties, showing the potential to complex two cations with
similar size and structure.3c Multisite receptors for simultaneous
binding of different cations and/or other types of guest molecules
by two different cavities above and below the porphyrin plane
are particularly attractive, but have not been reported to date.
To construct multisite receptor porphyrin–crown conjugates in
high yields, meso-4,6-dichloropyrimidinylporphyrinoids are attrac-
tive precursors.4,5 meso-Pyrimidinyl-substituted porphyrinoids
⇑
Corresponding authors. Tel.: +49 30 838 53 653; fax: +49 30 838 55 367
(T.H.N.); tel.: +32 16 327439; fax: +32 16 327990 (W.D.).
E-mail addresses: thien1981@zedat.fu-berlin.de (T.H. Ngo), wim.dehaen@chem.
kuleuven.be (W. Dehaen).
0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tetlet.2012.02.116

T. H. Ngo et al. / Tetrahedron Letters 53 (2012) 2406–2409
2407
Scheme 1. Synthesis of Zn(II)-A2B2-pyrimidinylporphyrin 4.
(porphyrins, corroles, hexaphyrins) have been shown to possess a
rather unique functionalization scope. Specific functionalities can
be introduced in a stepwise manner (by adjusting the reaction tem-
perature) above and below the tetrapyrrolic plane via nucleophilic
aromatic substitution (SNAr) or Pd-catalyzed cross-coupling reac-
tions (Suzuki, Stille, Liebeskind-Srogl). Compared to the above men-
tioned systems, meso-pyrimidinylporphyrins are easily prepared in
high yields and permit a straightforward introduction of crown
ether-like straps. In this Letter, the high versatility of meso-pyr-
imidinylporphyrin scaffolds is illustrated by the synthesis of a num-
ber of Zn-porphyrins with bridging crown ether-like moieties. One
of the main advantages of such systems over traditional receptors
is the ability to insert (different) complexing moieties both above
and below the porphyrin plane to enable simultaneous binding of
two (different) guest molecules. Axial ligation to the Zn(II) metal
ion in the porphyrin center can be employed as an additional com-
plexation tool.
afforded A2B2-porphyrin 3 in an optimized 65% yield, which is
extraordinarily high in porphyrin chemistry (Scheme 1). After met-
allation with zinc(II) acetate in chloroform (in a quantitative yield),
‘double-picket fence’7 Zn(II)-pyrimidinylporphyrin 4 was obtained,
which was then applied further on as the porphyrin building block
for the construction of the crown ether-bridged porphyrinreceptors.
As it was observed before that SNAr reactions on pyrimidinyl-
porphyrins proceed smoother with phenol rather than alcohol
nucleophiles,4,5
a triethylene glycol derivative 5 (1,8-bis(2-
hydroxyphenoxy)-3,6-dioxaoctane; Scheme 2)8 with catechol end
groups was prepared. A solution of Zn(II)-porphyrin 4 in DMF
and a solution of bis(catechol)-functionalized strap 5 (1 equiv) in
DMF were simultaneously added dropwise to a mixture of K2CO3
and 18-crown-6 in DMF at 90 °C over 2 h in a standard high-dilu-
tion procedure (with the aid of a syringe pump) favoring macrocyc-
lization (Scheme 2).
After purification of the crude porphyrin material by column
chromatography, 42% of mono(oligoether-strapped) porphyrin 6
was obtained (while 38% of unreacted Zn(II)-porphyrin 4 was
recovered).
Lewis acid-catalyzed (BF3ÁOEt2) condensation of mesityldipyr-
romethane (1)6 and 4,6-dichloro-2-methylsulfanyl-pyrimidine-
5-carbaldehyde (2),4a,4b followed by oxidation with p-chloranil,
The same reaction was also explored applying ultrasonification,
affording a similar yield for the monosubstituted receptor 6 (35%)
at a much lower reaction temperature (40 °C). To obtain bis(oligoe-
ther-strapped) porphyrin 7, monocrown–porphyrin conjugate 6
Scheme 2. Synthesis of mono- and bis(oligoether-strapped) Zn(II)-pyrimidinylpor-
phyrins 6 and 7.
Scheme 3. Synthesis of asymmetrically bis(oligoether-strapped) Zn(II)-pyr-
imidinylporphyrin 10.

2408
T. H. Ngo et al. / Tetrahedron Letters 53 (2012) 2406–2409
Figure 1. Molecular structure (ORTEP)12 of 7, with thermal ellipsoids drawn on the 30% probability scale. Due to the crystallographic inversion center, the Zn atom, O6, and
one carbon atom are disordered on two positions. Only one set of these disordered atoms is shown for clarity. Hydrogen atoms are omitted in the plot.
and a second equivalent of triethylene glycol-based linker 5 were
combined in a similar high-dilution SNAr reaction at 120 °C. As
reported before, the extent of substitution on meso-dic-
hloropyrimidinylporphyrinoids can be regulated to some extent
by the reaction temperature, allowing stepwise introduction of
functional moieties.4,5 After purification by column chromatogra-
on the size of the binding cavities, it was tried to grow single
crystals suitable for X-ray diffraction studies. For conjugate 7, sin-
gle crystals were obtained by slow evaporation of the solvent
(benzene) (Fig. 1). The Zn2+ ion is coordinated by the four pyrrolic
nitrogen atoms (Zn1a-N 2.002–2.131(3) Å) and one oxygen atom of
the oligoether chain (Zn1a-O6a = 2.238(4)
Å vs Zn1a-O6b =
phy, 47% of bis(oligoether-strapped) Zn(II)-porphyrin
7
was
4.496(4) Å) in a square pyramidal coordination mode. The Zn2+
-
obtained (and 32% of unreacted monocrown–porphyrin conjugate
6 was recovered simultaneously). Direct synthesis of biscrown–
porphyrin receptor 7 from Zn(II)-porphyrin precursor 4 was also
feasible (at 120 °C), affording 30% of the desired ‘gyroscope’9 por-
phyrin 7 (Scheme 2).
O6b distance is beyond the sum of the van der Waals radii. Due
to coordination to the oxygen atom O6a, the zinc ion is shifted
out of the square plane of the four nitrogen atoms (N1-Zn1a-N1i
160.65(4), N2-Zn1a-N2i 160.92(4)).3b,11 The meso-substituents
are approaching almost perpendicular positions with respect to
the porphyrin plane (with dihedral angles ranging from 75.51° to
84.05° for the pyrimidinyl rings, and from 79.19° to 82.11° for
the mesityl units).
To create a multisite receptor for different cations and/or other
guest molecules close to the porphyrin core, the above mentioned
stepwise SNAr procedure was again applied, but this time two dif-
ferent oligoethylene glycol-based linkers were employed to con-
struct two binding cavities with different dimensions. A 1:1 ratio
of tetraethylene glycol-bis(catechol) linker 8 and Zn(II)-porphyrin
4 was added dropwise to a solution of K2CO3 and 18-crown-6 in
DMF at 90 °C over two hours in a similar high-dilution procedure
to afford 40% of mono(oligoether-strapped) Zn(II)-porphyrin 9
(while 29% of Zn(II)-porphyrin 4 was recovered as well) (Scheme
3). The other porphyrin plane is now available for the connection
of a smaller second bridging unit. Triethylene glycol-based linker
5 was appended on 9 by the same protocol (at 120 °C) to afford
the asymmetrically substituted Zn(II)-porphyrin macrotricyclic
receptor 10 in 39% yield (31% of 9 was recovered) (Scheme 3).
The different sizes of the crown ether-like cavities above and
below the porphyrin plane provide the opportunity to act as a
receptor for different guest molecules simultaneously with a dis-
crimination based on size.
All novel porphyrin–crown conjugates were adequately charac-
terized by NMR (1H and 13C), (high resolution) electrospray ioniza-
tion mass spectrometry (ESI), and UV–Vis spectroscopy. As the
crown ether-like straps are positioned above and below the porphy-
rin plane, a gradual upfield shift of the ethylene glycol protons
depending on their relative position to the porphyrin center was
observed in the 1H NMR spectra.9 For asymmetrical gyroscope
porphyrin 10,10 two methylene units were observed below 0 ppm,
Conclusions
Straightforward (stepwise) functionalization of an A2B2-type
Zn(II)-meso-pyrimidinylporphyrin by SNAr reactions allowed to
introduce crown ether-like bridges above and below the porphyrin
plane, creating binding cavities located close to the center of the tet-
rapyrrolic macrocycle. Both symmetrically and asymmetrically
bis(oligoether-strapped) gyroscope porphyrins were prepared by a
direct connection of catechol-substituted oligoethylene glycol-
based linkers to the Zn(II)-porphyrin precursor. The asymmetrically
bis(oligoether-strapped) porphyrin has the potential to act as a mul-
tisite host molecule with simultaneous complexation of different
(size) guest ions/molecules. Current work focuses on complexation
studies applying the presented porphyrin–crown receptors and an
extension to meso-pyrimidinylcorroles. The synthetic study will
also be extended to the preparation of catenanes and rotaxanes with
oligoether-strapped porphyrins as core structures.2f,n,3d,13
Acknowledgments
We thank the IWT (Institute for the Promotion of Innovation
through Science and Technology in Flanders) and the Alexander
von Humboldt Foundation for a doctoral and postdoctoral fellow-
ship, respectively, to T.H. Ngo, and the KU Leuven and the Ministe-
rie voor Wetenschapsbeleid for continuing financial support.
W. Maes is grateful to the FWO (Fund for Scientific Research—
Flanders) for financial support and a postdoctoral fellowship.
at
d
À0.56 and À0.74 ppm (one well-resolved triplet at
d
À0.66 ppm for 9).
To observe the conformations of the novel oligoether-strapped
porphyrin materials in the solid state, providing useful information

T. H. Ngo et al. / Tetrahedron Letters 53 (2012) 2406–2409
2409
W.; Maes, W. J. Org. Chem. 2010, 75, 2127–2130; (e) Ngo, T. H.; Puntoriero, F.;
Nastasi, F.; Robeyns, K.; Van Meervelt, L.; Campagna, S.; Dehaen, W.; Maes, W.
Chem. Eur. J. 2010, 16, 5691–5705; (f) Nastasi, F.; Campagna, S.; Ngo, T. H.;
Dehaen, W.; Maes, W.; Kruk, M. Photochem. Photobiol. Sci. 2010, 10, 143–150.
6. (a) Lee, C.-H.; Lindsey, J. S. Tetrahedron 1994, 50, 11427–11440; (b) Rohand, T.;
Dolusic, E.; Ngo, T. H.; Maes, W.; Dehaen, W. ARKIVOC 2007, x, 307–324.
7. Collman, J. P.; Gagne, R. R.; Halbert, T. R.; Marchon, J. C.; Reed, C. A. J. Am. Chem.
Soc. 1973, 95, 7868–7870.
8. (a) Colquhoun, H. M.; Goodings, E. P.; Maud, J. M.; Stoddart, J. F.;
Wolstenholme, J. B.; Williams, D. J. J. Chem. Soc., Perkin Trans. 2 1985, 607–
624; (b) van Staveren, C. J.; van Eerden, J.; van Veggel, F. C. J. M.; Harkema, S.;
Reinhoudt, D. N. J. Am. Chem. Soc. 1988, 110, 4994–5008; (c) Van Rossom, W.;
Maes, W.; Kishore, L.; Ovaere, M.; Van Meervelt, L.; Dehaen, W. Org. Lett. 2008,
10, 585–588.
9. (a) Boitrel, B.; Lecas, A.; Renko, Z.; Rose, E. J. Chem. Soc., Chem. Commun. 1985,
1820–1821; (b) Rose, E.; Ren, Q.-Z.; Andrioletti, B. Chem. Eur. J. 2004, 10, 224–
230; (c) Fantauzzi, S.; Gallo, E.; Rose, E.; Raoul, N.; Caselli, A.; Issa, S.; Ragaini, F.;
Cenini, S. Organometallics 2008, 27, 6143–6151; (d) Rose, E.; Gallo, E.; Raoul, N.;
Bouché, L.; Pille, A.; Caselli, A.; Lequin, O. J. Porphyrins Phthalocyanines 2010, 14,
646–659.
10. Asymmetrical bis(oligoether-strapped) Zn-porphyrin 10. To a stirred suspension
of 18-crown-6 (5 mg, 0.02 mmol) and K2CO3 (0.092 g, 0.67 mmol) in DMF
(70 mL) at 120 °C, two solutions of mono(oligoether-strapped) Zn-porphyrin 9
Supplementary data
Supplementary data (experimental and characterization data
for all novel compounds, 1H and 13C NMR spectra for these deriva-
tives and HRMS spectra for the oligoether-strapped Zn-porphyrins)
associated with this article can be found, in the online version, at
http://dx.doi.org/10.1016/j.tetlet.2012.02.116. These data include
MOL files and InChiKeys of the most important compounds
described in this article.
References and notes
1. (a) Dumaine-Bouaziz, M.; Morelis, R. M.; Cordier, D.; Coulet, P. R. Biosens.
Bioelectron. 1999, 14, 289–294; (b) Nair, P. S.; Robinson, W. E. Environ. Toxicol.
Chem. 2001, 20, 1596–1604; (c) Merce, A. L. R.; Landaluze, J. S.; Mangrich, A. S.;
Szpoganicz, B.; Sierakowski, M. R. Bioresour. Technol. 2001, 76, 29–37; (d)
Alpturk, O.; Rusin, O.; Fakayode, S. O.; Wang, W. H.; Escobedo, J. O.; Warner, I.
M.; Crowe, W. E.; Král, V.; Pruet, J. M.; Strongin, R. M. Proc. Natl. Acad. Sci. U.S.A.
2006, 103, 9756–9760; (e) Pokhrela, D.; Viraraghavan, T. Chem. Eng. J. 2008,
140, 165–172; (f) Tomczyszyn, A. T.; Glowinska, A.; Wojcik, A.; Toth, G.;
Lipkowski, A. W.; Misicka, A. J. Peptide Sci. 2010, 16, 132–133.
2. (a) Knipe, A. C. J. Chem. Educ. 1976, 53, 618–622; (b) Kobashi, N.; Osa, T.
Heterocycles 1981, 15, 675–678; (c) Gunter, M. J.; Mander, L. N. J. Org. Chem.
1981, 46, 4792–4795; (d) Thanabal, V.; Krishnan, V. J. Am. Chem. Soc. 1982, 104,
3643–3650; (e) Gunter, M. J.; Johnston, M. R. Tetrahedron Lett. 1992, 33, 1771–
1774; (f) Gunter, M. J.; Hockless, D. C. R.; Johnston, M. R.; Skelton, B. R.; White,
A. H. J. Am. Chem. Soc. 1994, 116, 4810–4823; (g) Shinmori, H.; Osuka, A.
Tetrahedron Lett. 2000, 41, 8527–8531; (h) Duggan, S. H.; Fallon, G.; Langford, S.
J.; Lau, V.-L.; Satchell, J. F.; Paddon-Row, M. N. J. Org. Chem. 2001, 66, 4419–
4426; (i) Robertson, A.; Ikeda, M.; Takeuchi, M.; Shinkai, S. Bull. Chem. Soc. Jpn.
2001, 74, 883–888; (j) Gotardo, M. C. A. F.; Sacco, H. C.; Filho, J. C. S.; Ferreira, A.
G.; Tedesco, A. C.; Assis, M. D. J. Porphyrins Phthalocyanines 2003, 7, 339–404;
Ghiggino, K. P.; Hutchison, J. A.; Shafiqul Islan, D.-M.; Araki, Y.; Ito, O.; Langford,
S. J.; Lau, V.-L.; Takezaki, M. Photochem. Photobiol. Sci. 2006, 5, 1150–1153; (l)
Ishii, Y.; Yoshizawa, T.; Kubo, Y. Org. Biomol. Chem. 2007, 5, 1210–1217; (m) Liu,
Y.-C.; Kuo, M.-C.; Lee, C.-W.; Liang, Y.-R.; Lee, G.-H.; Peng, S.-M.; Yeh, C.-Y.
Tetrahedron Lett. 2008, 49, 7223–7226; (n) Marois, J.-S.; Cantin, K.; Desmarais,
A.; Morin, J.-F. Org. Lett. 2008, 10, 33–36; (o) Lu, L.; Wu, L.; Jiang, J.; Zhang, X.
Eur. J. Inorg. Chem. 2010, 4000–4008; (p) D’Souza, F.; Maligaspe, E.;
Sandanayaka, A. S. D.; Subbaiyan, N. K.; Karr, P. A.; Hasobe, T.; Ito, O. J. Phys.
Chem. A 2010, 114, 10951–10959; (q) Preihs, C.; Magda, D.; Sessler, J. L. J.
Porphyrins Phthalocyanines 2011, 15, 539–546.
3. (a) Gunter, M. J.; Johnston, M. R. Tetrahedron Lett. 1990, 31, 4801–4804; (b)
Comte, C.; Gros, C. P.; Koeller, S.; Guilard, R.; Nurco, D. J.; Smith, K. M. J. New
Chem. 1998, 621–626; (c) Michaudet, L.; Richard, P.; Boitrel, B. Tetrahedron Lett.
2000, 41, 8289–8292; (d) Lui, H.; Shao, X.-B.; Jia, M.-X.; Jiang, X.-K.; Li, Z.-T.;
Chen, G.-J. Tetrahedron 2005, 61, 8095–8100; (e) Mullen, K. M.; Gunter, M. J. J.
Org. Chem. 2008, 73, 3336–3350.
4. (a) Motmans, F.; Ceulemans, E.; Smeets, S.; Dehaen, W. Tetrahedron Lett. 1999,
40, 7545–7548; (b) Smeets, S.; Asokan, C. V.; Motmans, F.; Dehaen, W. J. Org.
Chem. 2000, 65, 5882–5885; (c) Maes, W.; Dehaen, W. Synlett 2003, 79–82; (d)
Maes, W.; Vanderhaeghen, J.; Dehaen, W. Chem. Commun. 2005, 2612–2614; (e)
Maes, W.; Vanderhaeghen, J.; Smeets, S.; Asokan, C. V.; Van Renterghem, L. M.;
Du Prez, F. E.; Smet, M.; Dehaen, W. J. Org. Chem. 2006, 71, 2987–2994; (f) Maes,
W.; Dehaen, W. Pol. J. Chem. 2008, 82, 1145–1160.
(0.040 g, 0.031 mmol) and tetraethylene glycol-based linker
5 (0.010 g,
0.031 mmol) in DMF (10 mL) were simultaneously added dropwise using a
syringe pump over a period of 2 h. The mixture was additionally stirred for
another h at 120 °C. DMF was evaporated under reduced pressure, and after
column chromatographic purification (silica, eluent CH2Cl2), pure
asymmetrical bis(oligoether) Zn-porphyrin conjugate 10 was obtained as a
purple solid (19 mg, 39%). HRMS (ESI+) calcd for C86H80N8O13S2Zn: m/z
1562.4548; found: 1562.4642; 1H NMR (600 MHz, CDCl3)
d 9.11 (d,
J = 4.5 Hz, 4H, Hb), 8.77 (d, J = 4.5 Hz, 4H, Hb), 7.71 (d, J = 8.3 Hz, 2H, Ho-Ph),
7.49 (d, J = 8.3 Hz, 2H, Ho-Ph), 7.29 (s, 2H, Hmesit), 7.27 (s, 2H, Hmesit), 7.00 (t,
J = 7.0 Hz, 2H, Hm-Ph), 6.97À6.92 (m, 4H, Hm-Ph), 6.89 (t, J = 7.3 Hz, 2H, Hm-Ph),
6.63 (d, J = 7.9 Hz, 2H, HPh), 6.48 (d, J = 7.9 Hz, 2H, HPh), 3.46 (sbr, 4H, CH2), 2.66
(t, J = 5.3 Hz, 4H, CH2), 2.63 (s, 6H), 2.45 (sbr, 10H), 1.94 (s, 6H), 1.80 (s, 6H), 1.03
(sbr, 4H, CH2), 0.20 (sbr, 4H, CH2), À0.56 (sbr, 4H, CH2), À0.74 (sbr, 4H, CH2); 13
C
NMR (100 MHz, CDCl3) d 170.7, 169.0, 168.7, 150.5, 150.2, 149.8, 143.6, 142.5,
139.5/139.4, 139.2, 137.5, 131.4/131.3 (CH), 127.9/127.8 (CH), 125.8 (CH),
125.3 (CH), 124.4 (CH), 123.2 (CH), 121.3 (CH), 120.6 (CH), 118.8, 117.1 (CH),
115.1 (CH), 108.0, 104.4, 100.2, 70.8 (CH2), 69.7 (CH2), 68.9 (CH2), 68.0 (CH2),
67.3 (CH2), 66.9 (CH2), 66.3 (CH2), 22.8 (CH3), 22.3 (CH3), 22.1 (CH3), 21.6 (CH3),
14.5 (CH3); UV–vis (CH2Cl2) kmax (loge) 253 (4.586), 311 (4.312), 406 (4.624),
427 (5.755), 556 (4.334), 597 (3.811).
11. X-ray single-crystal diffraction of compound 7 was performed on a Bruker AXS
Smart CCD. The structures were solved by direct methods, using SHELXS-97.
Refinement was done with the least squares method (SHELXL-97). Molecular
Graphics: ORTEP-3 for Windows.11 Crystal data for 7: C88H68Cl8N8O12S2Zn,
M = 1842.59, triclinic, a = 13.193(4) Å, b = 13.396(4) Å, c = 14.188(5) Å,
a
= 74.440(7)°, b = 86.652(7)°,
c
a
= 61.958(8)°, V = 2125.2(12) Å3, T = 133(2) K,
space group P-1, Z = 1, (MoK
l
) = 0.656 mmÀ1, 15360 reflections measured,
8266 independent reflections (Rint = 0.0189), R1 = 0.0645 (I >2r(I)),
wR(F2) = 0.1860 (all data). The goodness of fit on F2 was 1.037. CCDC 855226
contains the supplementary crystallographic data for this paper. These data
can be obtained free of charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
12. Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565.
13. (a) Megiatto, J. D.; Schuster, D. I.; Abwandner, S.; de Miguel, G.; Guldi, D. M. J.
Am. Chem. Soc. 2011, 132, 3847–3861; (b) Han, M.; Zhang, H.-Y.; Yang, L.-X.;
Ding, Z.-J.; Zhuang, R.-J.; Liu, Y. Eur. J. Org. Chem. 2011, 7271–7277; (c) Roche,
C.; Sauvage, J.-P.; Sour, A.; Strutt, N. L. J. New Chem. 2011, 35, 2820–2825; (d)
Brown, A.; Beer, P. D. Dalton Trans. 2012, 41, 118–129.
5. (a) Asokan, C. V.; Smeets, S.; Dehaen, W. Tetrahedron Lett. 2001, 42, 4483–4485;
(b) Maes, W.; Ngo, T. H.; Vanderhaeghen, J.; Dehaen, W. Org. Lett. 2007, 9, 3165–
3168; (c) Ngo, T. H.; Van Rossom, W.; Dehaen, W.; Maes, W. Org. Biomol. Chem.
2009, 7, 439–443; (d) Ngo, T. H.; Nastasi, F.; Puntoriero, F.; Campagna, S.; Dehaen,