Design and synthesis of new differentiated concurrent mono- and tridentate ligands (tectons) based on pyridine, terpyridine, and dihydrooxazole units

Article abstract of DOI:10.1002/hlca.200900087

The design, synthesis, and characterization of the 10 linear and bent acentric ligands 1 - 10 (tectons) based on the differentiation of two divergently disposed coordinating poles is reported. The nature of the two poles and their distance are varied by t

Full text of DOI:10.1002/hlca.200900087

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Design and Synthesis of New Differentiated Concurrent Mono- and Tridentate
Ligands (Tectons) Based on Pyridine, Terpyridine, and Dihydrooxazole Units
by Abdelaziz Jouaiti* and Mir Wais Hosseini*
´
Universite de Strasbourg, Laboratoire de Chimie de Coordination Organique,UMR CNRS 7140,
´
Tectonique Moleculaire du Solide, Institut Le Bel, 4, rue Blaise Pascal, F-67000 Strasbourg
(e-mail: hosseini@chimie.u-strasbg.fr)
Dedicated to Professor Jean-Claude Bꢀnzli on the occasion of his 65th birthday
The design, synthesis, and characterization of the 10 linear and bent acentric ligands 1 – 10 (tectons)
based on the differentiation of two divergently disposed coordinating poles is reported. The nature of the
two poles and their distance are varied by the use of different linear spacers. For these molecules, a
monodentate coordinating site, i.e., a pyridine ring, and a tridentate coordinating site, i.e., a pyridine
moiety bearing at the 2 and 6 positions either two thioether groups or two dimethylamino units (PySMe
and PyN(Me2)2 type, resp.), a terpyridine, or a pyridine ring bearing two optically pure dihydrooxazole
units, are combined.
Introduction. – Considering a molecular crystal as a supramolecular assembly [1]
composed of molecular tectons [2][3] capable of mutual recognition opens the way to
design new construction units and new crystalline architectures. This area, called
molecular tectonics [2 – 4], has attracted considerable interest over the last ca. two
decades. The molecular-tectonics approach, a subset of supramolecular chemistry in the
solid state, is based on iterative recognition events occurring under self-assembly
conditions. In other words, the formation of periodic architectures (1 – 3D) in the
crystalline phase is achieved by self-assembly of molecular tectons bearing within their
structure at least two specific interaction sites oriented in a divergent fashion. The
recognition process may be based on any type of attractive forces. We shall here restrict
the discussion to the use of coordination bonding as the dominant event generating the
network [5][6]. This type of architecture is called coordination network since it is based
on a coordinating organic tecton and a metal center or metal complex offering at least
two free coordination sites. Thus, for this type of assembly, the recognition patterns are
coordination motives resulting from the binding of the metal by the tecton. Through the
repetitive coordination events, the recognition patterns become structural nodes of the
network.
One of the major challenges in this area today remains the design of polar crystals
(Fig. 1, F) resulting from the noncentrosymmetric arrangement of molecular tectons.
Let us consider the formation of 1-D coordination networks (translated into a single
direction of space of the coordination event) and their packing leading to hybrid
crystals (Fig. 1). In this context, the formation of the crystal results from the packing of
1-D networks (see B) in two different planes, i.e., the formation of sheets through
ꢀ 2009 Verlag Helvetica Chimica Acta AG, Zꢁrich

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lateral packing of 1-D networks (see C and D) and the packing of sheets leading to the
tridimensional crystalline solids (see E and F).
Fig. 1. Schematic representation of 1-D directional coordination networks B formed by combining a
directional tecton A and a metal center, and their packing, supposing a parallel mode of arrangement, into
centric sheets C or directional sheets D and subsequent packing of the latter affording either apolar or polar
3-D architectures E or F, respectively
A possible design strategy for the formation of polar crystals may be based on the
use of a noncentrosymmetric organic tecton bearing two different coordinating sites
(Fig. 1, A). The latter, in the presence of an appropriate metal center or complex,
would lead to the formation of a 1-D directional network B. Supposing a parallel mode
of packing, the consecutive 1-D networks may either be arranged in acentric (see D) or
centric (see C) modes leading to the formation of directional and nondirectional sheets,
respectively. Finally, whereas the packing of centric sheets C would generate an apolar
crystal, for the acentric sheet D, either an acentric (see F) or a centric (see E) mode of
arrangement are possible.
Our strategy to investigate this issue was based on the use of linear and bent
noncentrosymmetric organic tectons of the type T1,3 bearing both a monodentate and a
tridentate coordinating pole (for definition, see [7]). Indeed, the combination of such
units with either a metal center adopting the square planar geometry G (Fig. 2) or with
a metal center offering the octahedral geometry H with the two apical positions
blocked by coordinating anions and thus offering four free coordination sites occupying
the corner of a square should, by design, lead to the formation of 1-D directional
networks. This principle was demonstrated in the crystalline phase by combining
tectons 3 [8], 5 [7], or 7 [9] with CoCl2. Furthermore, with tectons 9 [10] and 10 [11],
the concept was extended to graphite-surface patterning in the presence of either CoCl2
or Pd(BF4)2.
It is interesting to note that in the crystalline phase, although the combination of
tectons 5 [7] or 7 [8] with CoCl2 indeed leads to the formation of neutral 1-D directional
networks H (Fig. 2), unfortunately, the packing of consecutive networks takes place in
the centric mode and consequently, the crystals obtained are apolar. However, with the
chiral and optically pure tecton 3, the arrangement of chiral 1-D networks in the plane
leads to the formation of polar sheets D and the packing of the latter generates a polar
cystal F (Fig. 1) [8].

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Fig. 2. Schematic representation of 1-D directional coordination networks formed upon combining an
acentric organic tecton based on a monodentate and a tridentate coordinating pole with metal centers
adopting either a square planar geometry G or an octahedral geometry H with protected apical positions
Here we report on the design, synthesis, and characterization of noncentric tectons
1 – 10. The noncentric tectons 3 [8], 5 [7], 7 [9], and 9 [10] have briefly been described,
and the synthesis of 10 has already been reported [11].
Results and Discussion. – Tectons 1 and 2 are based on a pyridine unit behaving as a
monodentate coordinating site, and a tridentate pole composed of a pyridine moiety
bearing either two thioether groups (PySMe2 type) or two dimethylamino groups
(PyN(Me2)2 type) at the 2 and 6 positions. The synthesis of 1 and 2 was based on the
Suzuki coupling reaction between the pyridin-4-ylboronic acid and the bromo
compounds 15 and 16, respectively. Starting with the commercially available chelidamic
acid (¼4-hydroxypyridine-2,6-dicarboxylic acid; 11), bromination with PBr5 followed
by esterification of the two COOH groups with EtOH afforded diester 12 in 61% yield
[12]. The latter was reduced with NaBH4 in dry EtOH to diol 13 in 62% yield [13].
Although the preparation of compound 14 from diol 13 with PBr3 was reported [13], we
found that the bromination with 33% HBr/AcOH at 1258 for 5 h was much more
efficient and produced compound 14 in 89% yield. The treatment of 14 with MeSNa in
dry THF for 48 h at room temperature afforded the precursor 15 in 70% yield, and the
condensation of 14 with Me2NH in MeCN afforded the tridentate diamine 16 [14]. The
synthesis of ligands 1 and 2 was achieved by coupling pyridin-4-ylboronic acid with the
bromopyridine derivatives 15 and 16, respectively, in the presence of [Pd(Ph3P)4] and
Cs2CO3 in DMF at 908 overnight. The pure compounds 1 and 2 were obtained as
yellowish viscous oils in 81 and 78% yield, respectively, after chromatography (Al2O3).
The C2 chiral tectons 3 and 4 are again based on two coordination poles composed
of a pyridine unit connected at the 4-position to a pyridine unit bearing at the 2 and 6
positions two optically active monodentate dihydrooxazole moieties. The strategy for
the synthesis of 3 and 4 was also based on the Suzuki coupling between 18 [15] or 19,
which were prepared by slight modifications of the reported procedure [15], and
pyridin-4-ylboronic acid. Chelidamic acid (11) was again the starting material. The
treatment of the latter with SOCl2 in the presence of a drop of DMF afforded the acyl
chloride derivative 17. The chirality of the final ligands 3 and 4 was imposed upon
treatment of 17 with (S)-valinol (¼(2S)-2-amino-3-methylbutan-1-ol) or (ꢀ)-(R)-2-
phenylglycinol (¼(2R)-2-amino-2-phenylethanol) in THF (08 to room temp.) in the
presence of Et3N affording 18 and 19 in 79 and 68% yield, respectively. The Suzuki

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coupling between 18 or 19 and pyridin-4-ylboronic acid or its cyclic ester 4-(4,4,5,5-
tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine [16] in the presence of [Pd(Ph3P)4] in
DMF and in the presence of Cs2CO3 afforded the 4,4’-bipyridine derivatives 20 and 21
in 89 and 91% yield, respectively. It is worth noting that no difference in yields was
observed upon substitution of the boronic acid by the cyclic boronic ester. The
chlorination of compounds 20 and 21 upon treatment with SOCl2 under reflux afforded
the dichloro derivatives 22 and 23 in ca. 95% yield. Finally, the desired ligands 3 and 4

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were obtained upon treatment of 22 with NaH in THF, and of 23 with NaOH in H2O/
MeOH in 79% and 86% yield, respectively.
Tecons 5 and 6 are longer analogues of ligands 1 and 2. Indeed, for these two
compounds, the two coordinating poles are preserved. However, to investigate the role
played by the distance between the poles on the formation of 1-D networks and their
packing, the two poles were separated by an ethynyl spacer which was chosen because
of its cylindrical shape and small diameter avoiding thus steric issues. The synthesis of
both 5 and 6 was based on the Sonogashira coupling reaction between compounds 15 or
16 with 4-ethynylpyridine (24). The latter was prepared according to a published
procedure [17]. Thus, the coupling of 24 with either bromo compound 15 or 16 in the
presence of [Pd(OAc)2]/Ph3P in Et3N afforded the desired compounds 5 and 6 in 62 and
94% yield, respectively.
Compounds 7 and 8, which may be regarded as achiral analogues of 3 and 4, are
based on a pyridine unit connected at the position 4 and 3, respectively, to a terpyridine
moiety through an ethynyl spacer. The difference between 7 and 8 resides in the
orientation of the monodentate site with respect to the tridentate pole imposed by the
connecting position (4 for 7 and 3 for 8). The synthesis of 7 and 8 was achieved again by

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the Sonogashira coupling reactions with [Pd(OAc)2]/Ph3P as the catalyst. The
condensation of bromoterpyridine 26 [18], prepared according to a published
procedure with either 4-ethynylpyridine (24) [17] or 3-ethynylpyridine (25) [19]
afforded the desired compounds 7 and 8 in 98 and 84% yield, respectively.
The two tectons 9 and 10 are longer analogues of ligands 7 and 8. They are
constructed around a spacer composed of an anthracene moiety bearing two ethynyl
units at positions 9 and 10. One of the two ethynyl spacers is connected to a pyridine
moiety either at position 4 (compound 9) or 3 (compound 10), and the remaining triple
bond is attached to a terpyridine group. Again, 9 and 10 differ only by the orientation of
the pyridine unit with respect to the terpyridine unit. To increase the interactions with
the graphite surface, the anthracene moiety was used to link the two ethynyl units
[10][11]. The synthesis of 9 and 10 [11] was based on a double Sonogashira reaction
with [Pd(OAc)2]/Ph3P as catalyst. Starting with 9,10-dibromoanthracene (27), the first
Sonogashira coupling reaction with 4-ethynylpyridine (24) [17] or with 3-ethynylpyr-
idine (25) [19] afforded the mono-functionalized anthracene derivatives 29 and 30 in 34
and 30% yields, respectively. The second coupling reaction between either 29 or 30 and
ethynylterpyridine 28, prepared according to a reported procedure [20], gave the final
compounds 9 and 10 in 80 and 87% yields, respectively. It is worth noting that the
above-mentioned condensation of 27 either with 24 or 25, in addition to the desired
compounds 29 and 30 gave the centrosymmetric bis-monodentate ligands 31 and 32 [11]
in 25 and 40% yields, respectively. These compounds are also interesting as tectons and
are currently employed for the formation of coordination networks.

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Conclusion. – A series of linear or bent acentric tectons based on the differentiation
of two coordinating poles were designed and synthesized by Suzuki or Sonogashira
coupling reactions. The nature of the two poles and their distance were varied by the
use of different linear spacers. Thus, these molecules 1 – 10 are composed of a
monodentate (pyridine) and a tridentate coordinating sites. The latter site consists of a
pyridine ring bearing at the 2 and 6 positions either two thioether groups (PySMe type)
or two dimethylamino units (PyN(Me2)2 type), a terpyridine, or a pyridine ring bearing
two optically pure dihydrooxazole units at positions 2 and 6. With some of these
tectons, the validity of the design principle, i.e., generation of infinite directional
coordination networks both in the crystalline phase [7 – 9] or on surfaces [10][11] was
demonstrated previously. The use of the remaining tectons for the formation of
oriented architectures is currently under investigation.
´
We thank the Universite de Strasbourg, CNRS, the Institut Universitaire de France (IUF), and the
International Center for Frontier Research in Chemistry (FRC), Strasbourg, for financial support.
Experimental Part
General. All commercially available reagents were used without further purification. THF was
distilled over Na. Compounds 10 [11], 12 [12], 13 [13] 14 [13], 16 [14], 24 [17], 25 [19], 26 [18], 28 [20], 30
[11], 31 [21], and 32 [11] were prepared according to published procedures. 1H- and 13C-NMR Spectra:
Bruker spectrometers, at 300 and 75 MHz, resp.; in CDCl3 unless otherwise specified; d in ppm rel. to
Me4Si as internal standard, J in Hz. Microanalyses were performed by the Service de Microanalyses de la
´
´
´
Federation de Recherche Chimie, Universite de Strasbourg.
4-Bromo-2,6-bis[(methylsulfanyl)methyl]pyridine (15). A soln. of 4-bromo-2,6-bis(bromomethyl)-
pyridine (14; 1 g, 2.9 mmol) and MeSNa (0.65 g, 9.27 mmol) in THF (25 ml) was stirred at r.t. for 48 h.
The soln. was concentrated, the org. residue dissolved in Et2O (50 ml), the mixture filtered, and the
filtrate washed with H2O (2 ꢁ 10 ml), dried, and concentrated affording a pure colorless oil which
crystallized upon standing overnight: 15 (0.57 g, 70%). 1H-NMR: 7.38 (s, 2 H); 3.68 (s, 4 H); 2.02 (s, 6 H).
13C-NMR: 159.7; 133.8; 124.3; 39.6; 15.3. Anal. calc. for C9H12BrNS2 (278.23): C 38.85, H 4.35, N 5.03;
found: C 38.95, H 4.42, N 4.98.
4-Chloro-N2,N6-bis[(1S)-1-(hydroxymethyl)-2-methylpropyl]pyridine-2,6-dicarboxamide (18) and 4-
Chloro-N2,N6-bis[(1R)-2-hydroxy-1-phenylethyl]pyridine-2,6-dicarboxamide (19) were prepared follow-
ing the same procedure. For 19, chelimadic acid (11; 1 g, 5.4 mmol) was treated with SOCl2 (25 ml) in the
presence of 2 drops of DMF under reflux for 36 h. Excess of SOCl2 was then evaporated to give the diacyl
chloride 17. To a soln. of (ꢀ)-(R)-2-phenylglycinol (13.2 mmol) and Et3N (5 ml) in THF (20 ml) was
slowly added a soln. of the diacyl chloride 17 in THF (30 ml) at 08. The mixture was stirred at r.t. for 24 h.
The THF was evaporated, the residue extracted with CH2Cl2 (100 ml), the extract washed with aq.
NaHCO3 soln. (60 ml), dried, and concentrated, and the residue purified by column chromatography
(CC; silica gel (SiO2): pure.
19 (68%). M.p. 638. 1H-NMR: 8.68 (d, J ¼ 7.6, 2 H); 8.18 (s, 2 H); 7.35 – 7.23 (m, 10 H); 5.22 – 5.17 (m,
2 H); 3.92 (d, J ¼ 4.9, 4 H); 3.41 (s, 2 H). 13C-NMR: 162.6; 150.1; 147.8; 138.6; 128.9; 127.9; 126.6; 125.4;
65.9; 55.7. Anal. calc. for C23H22ClN3O4 (439.90): C 62.80, H 5.04, N 9.55; found: C 63.01, H 5.14, N 9.73.
18: Yield 79%. For data, see [15].
Suzuki Coupling: General Method. [Pd(Ph3P)4] (0.06 g, 0.05 mmol) was added to a degassed soln. of
pyridin-4-ylboronic acid (0.33 g, 2.68 mmol), a halopyridine derivative (2.0 mmol), and Cs2CO3 (1.8 mol)
in DMF (15 ml). The mixture was heated to 908 under Ar for the time indicated (TLC monitoring). After
evaporation of the solvent, the residue was purified by CC (Al2O3) with the indicated eluent.
2,6-Bis[(methylsulfanyl)methyl]-4,4’-bipyridine (1): For 24 h; eluent cyclohexane/CH2Cl2 50 :50.
Yield 81%. Yellowish oil. 1H-NMR: 8.72 (d, J ¼ 6.1, 2 H); 7.55 (d, J ¼ 6.1, 2 H); 7.49 (s, 2 H); 3.86 (s, 4 H);

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2.10 (s, 6 H). 13C-NMR: 159.4; 150.4; 147.0; 145.7; 121.5; 119.0; 40.0; 15.3. Anal. calc. for C14H16N2S2
(276.42): C 60.83, H 5.83, N 10.13; found: C 60.73, H 5.76, N 10.03.
N2,N2,N6,N6-Tetramethyl[4,4’-bipyridine]-2,6-dimethanamine (2): For 24 h, CH2Cl2. Yield 78%.
1
Yellowish oil. H-NMR: 8.67 (d, J ¼ 6.1, 2 H); 7.57 (d, J ¼ 6.1, 2 H); 7.55 (s, 2 H); 3.64 (s, 4 H); 2.30 (s,
12 H). 13C-NMR: 159.7; 150.4; 146.4; 145.9; 121.4; 119.0; 65.7; 45.6. Anal. calc. for C16H22N4 (270.37): C
71.08, H 8.20, N 20.72; found: C 70.88, H 8.17, N 20.66.
N2,N6-Bis[(1S)-1-(hydroxymethyl)-2-methylpropyl][4,4’-bipyridine]-2,6-dicarboxamide (20): For
1
15 h; eluent 2% MeOH/CH2Cl2. Yield 89%. M.p. 1158. H-NMR: 8.72 (d, J ¼ 6.1, 2 H); 8.53 (s, 2 H);
8.13 (d, J ¼ 8.64, 2 H); 7.60 (d, J ¼ 6.1, 2 H); 3.98 – 3.94 (m, 2 H); 3.87 – 3.84 (m, 2 H); 3.27 (s, 2 H); 2.11 –
2.02 (m, 2 H); 1.03 – 0.96 (m, 12 H). 13C-NMR: 18.7; 19.6; 29.3; 57.2; 63.6; 121.3; 122.5; 143.9; 148.7;
149.9; 150.7; 163.6. Anal. calc. for C22H30N4O4 (414.50): C 63.75, H 7.30, N 13.52; found: C 63.96, H 7.11, N
13.60.
N2,N6-Bis[(1R)-2-hydroxy-1-phenylethyl][4,4’-bipyridine]-2,6-dicarboxamide (21): For 48 h; eluent
2% MeOH/CH2Cl2. Yield 91%. M.p. 1188. 1H-NMR (MeOD): 8.66 (d, J ¼ 6.1, 2 H); 8.60 (s, 2 H); 7.88 (d,
J ¼ 6.1, 2 H); 7.47 (d, J ¼ 7.4, 4 H); 5.31 (t, J ¼ 7.3, 2 H); 3.97 (d, J ¼ 7.4, 4 H). 13C-NMR (MeOD): 56.1;
64.8; 122.0; 122.4; 126.7; 127.2; 128.2; 139.4; 145.56; 147.9; 149.4; 150.4; 164.1. Anal. calc. for C28H26N4O4
(482.53): C 69.70, H 5.43, N 11.61; found: C 69.90, H 5.61, N 11.62.
N2,N6-Bis[(1S)-1-(chloromethyl)-2-methylpropyl][4,4’-bipyridine]-2,6-dicarboxamide (22) and
N2,N6-Bis[(1R)-2-chloro-1-phenylethyl][4,4’-bipyridine]-2,6-dicarboxamide (23) were prepared follow-
ing an identical procedure: To 20 or 21 (2 mmol) was added SOCl2 (20 ml), and the mixture was heated
under reflux for 7 h. The SOCl2 was evaporated, and the crude product was purified by CC (Al2O3, 1%
MeOH/CH2Cl2.
Data at 22: Yield 95%. White solid. M.p. 1628. 1H-NMR: 8.76 (d, J ¼ 6.1, 2 H); 8.53 (s, 2 H); 8.04 (d,
J ¼ 8.7, 2 H); 7.63 (d, J ¼ 6.1, 2 H); 4.19 – 4.13 (m, 2 H); 3.88 – 3.83 (m, 2 H); 3.78 – 3.72 (m, 2 H); 2.12 –
2.07 (m, 2 H); 1.04 – 0.98 (m, 12 H). 13C-NMR: 18.80; 19.3; 29.6; 46.8; 54.9; 121.3; 122.7; 143.9; 149.1;
149.6; 150.7; 162.6. Anal. calc. for C22H28Cl2N4O2 (451.39): C 58.54, H 6.25, N 12.41; found: C 58.43, H
6.11, N 12.29.
1
Data of 23: Yield 92%. White solid. M.p. 1808 (dec.). H-NMR: 8.76 (d, J ¼ 6.1, 2 H); 8.64 (d, J ¼
8.27, 2 H); 8.62 (s, 2 H); 7.64 (d, J ¼ 6.1, 2 H); 7.43 – 7.33 (m, 10 H); 4.03 – 3.98 (m, 2 H); 4.01 (m, 4 H).
13C-NMR: 48.3; 53.8; 121.5; 123.0; 126.6; 128.4; 128.9; 139.4; 144.2; 149.0; 149.6; 150.5; 162.5. Anal. calc.
for C28H24Cl2N4O2 (519.42): C 64.75, H 4.66, N 10.79; found: C 64.68, H 4.59, N 10.71.
2,6-Bis[(4S)-4,5-dihydro-4-(1-methylethyl)-1,3-oxazol-2-yl]-4,4’-bipyridine (3). To a suspension of
NaH (0.023 g, 0.95 mmol) in THF (10 ml), 22 (0.18 g, 0.4 mmol) was added. The mixture was stirred at
r.t. for 3 h. After filtration and concentration, Et2O (20 ml) was added and the residue filtered. The crude
mixture was recrystallized from Et2O/hexane: 3 as (79%). White needles. M.p. 1188. 1H-NMR: 8.76 (d,
J ¼ 6.2, 2 H); 8.47 (s, 2 H); 7.67 (d, J ¼ 6.2, 2 H); 4.56 (dd, J ¼ 8.2, 9.1, 2 H); 4.20 (t, J ¼ 8.3, 2 H); 4.19 –
4.14 (m, 2 H); 1.93 – 1.85 (m, 2 H); 1.07 (d, J ¼ 6.7, 6 H); 0.96 ((d, J ¼ 6.7, 6 H). 13C-NMR: 18.2; 19.0; 32.8;
71.1; 73.0; 121.5; 123.3; 144.1; 147.9; 150.8; 162.0. Anal. calc. for C22H26N4O2 (378.47): C 69.82, H 6.92, N
14.80; found: C 69.75, H 6.87, N 14.66.
2,6-Bis[(4R)-4,5-dihydro-4-phenyl-1,3-oxazol-2-yl]-4,4’-bipyridine (4). Compound 23 (0.42 g,
0.8 mmol) was treated with a soln. of NaOH (0.3 g, 7.5 mmol) in H2O (5 ml) and MeOH (12 ml) at r.t.
for 20 h. After extraction with CH2Cl2 (2 ꢁ 50 ml), the org. layer was dried (MgSO4) and concentrated
and the residue purified by CC (SiO2, 2% MeOH/CH2Cl2): 4 (86%). White solid. M.p. 1168. 1H-NMR:
8.75 (d, J ¼ 6.2, 2 H); 8.61 (s, 2 H); 7.66 (d, J ¼ 6.2, 2 H); 7.43 – 7.28 (m, 10 H); 5.49 (dd, J ¼ 8.6, 9.2, 2 H);
4.96 (dd, J ¼ 8.6, 9.2, 2 H); 4.46 (dd, J ¼ 8.6, 9.2, 2 H). 13C-NMR: 70.4; 75.7; 121.5; 123.9; 126.9; 127.9;
128.9; 141.4; 143.8; 147.4; 147.8; 150.8; 163.3. Anal. calc. for C28H22N4O2 (446.51): C 75.32, H 4.97, N 12.55;
found: C 75.11, H 5.12, N 12.71.
4-[2-(10-Bromoanthracen-9-yl)ethynyl]pyridine (29). To a degassed mixture of 4-ethynylpyridine
(24; 0.50 g, 4.8 mmol) and 9,10-dibromoanthracene (2 g, 5.9 mmol) in Et3N (20 ml) (Schlenk flask) were
added [Pd(OAc)2] (0.024 g, 0.1 mmol) and Ph3P (0.054 g, 0.2 mmol). The mixture was refluxed for 24 h,
after which the solvent was evaporated. The crude product was purified by CC (SiO2, CH2Cl2/MeOH
99 :1): 29 (0.6 g, 34%) and 4,4’-(anthracene-9,10-diyldiethyne-2,1-diyl)bis[pyridine] (31; 25%). For anal.
1
data of 31, see [21]. 29: M.p. 1128. H-NMR: 7.71 (d, J ¼ 6.3, 2 H); 8.65 – 8.58 (m, 4 H); 7.68 – 7.61 (m,

Helvetica Chimica Acta – Vol. 92 (2009)
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6 H). 13C-NMR: 149.9; 135.9; 130.3; 129.0; 128.4; 127.6; 127.3; 126.8; 126.4; 123.7; 119.4; 86.9; 80.6. Anal.
calc. for C21H12BrN (358.23): C 70.41, H 3.38, N 3.91; found: C 70.44, H 3.67, N 3.88.
4’-{2-{10-[2-(Pyridin-4-yl)ethynyl]anthracen-9-yl}ethynyl}-2,2’:6’,2’’-terpyridine (9). As described for
29, with 4’-ethynyl-2,2’:6’,2’’-terpyridine (0.107 g, 0.41 mmol), 29 (0.150 g, 0.41 mmol), Et3N (20 ml),
Pd(OAc)2 (0.024 g, 0.1 mmol), and Ph3P (0.054 g, 0.2 mmol). CC (Al2O3, CH2Cl2) afforded 9 (0.160 g,
80%). Orange solid. M.p. 1908 (dec.). 1H-NMR: 8.81 – 8.77 (m, 6 H); 8.72 (dd, J ¼ 2.7, 6.3, 2 H); 8.69 (d,
J ¼ 8, 2 H); 8.66 – 8.63 (m, 2 H); 7.92 (td, J ¼ 7.9, 1.8, 2 H); 7.74 – 7.70 (m, 4 H); 7.43 – 7.39 (m, 2 H); 7.63
(dd, J ¼ 2.7, 6.3, 2 H). Anal. calc. for C38H22N4 (534.62): C 85.37, H 4.15, N 10.48; found: C 85.63, H 4.25, N
10.56.
Sonogashira Coupling: General Method. To a degassed mixture of 4-ethynylpyridine (24; 0.8 g,
0.78 mmol) and a halopyridine derivative (0.50 mmol) in Et3N (20 ml) (Schlenk flask) were added
[Pd(OAc)2] (0.024 g, 0.1 mmol) and Ph3P (0.054 g, 0.2 mmol).The mixture was refluxed for 48 h, after
which the solvent was evaporated. The crude product was purified by CC.
2,6-Bis[(methylsulfanyl)methyl]-4-[2-(pyridin-4-yl)ethynyl]pyridine (5). CC (SiO2, CH2Cl2/MeOH
99 :1). Yield 94%. Oil. 1H-NMR: 2.08 (s, 6 H); 3.79 (s, 4 H); 7.31 (s, 2 H); 7.38 (d, J ¼ 6, 2 H); 8.63 (d, J ¼
6, 2 H). 13C-NMR: 15.3; 39.9; 90.05; 90.1; 123.0; 125.6; 130.3; 131.5; 150.0; 158.8. Anal. calc. for
C16H16N2S2 (300.44): C 63.97, H 5.37, N 9.32; found: C 64.10, H 5.66, N 9.15.
N2,N2,N6,N6-Tetramethyl-4-[2-(pyridin-4-yl)ethynyl]pyridine-2,6-dimethanamine (6). CC (Al2O3,
1
hexane/AcOEt). Yield 92%. Oil. H-NMR (200 MHz): 2.26 (s, 12 H, Me); 3.55 (s, 2 CH2); 7.3 (dd, J ¼
6, 1.6, 2 H); 7.38 (s, 2 H); 8.57 (dd, J ¼ 6, 1.6, 2 H). 13C-NMR: 45.7; 65.6; 89.8; 91.5; 123.1; 125.6;
128.5; 130.7; 149.9; 159.3. Anal. calc. for C18H22N4 (294.39): C 73.44, H 7.53, N 19.03; found: C 73.12, H
7.22, N 18.85.
4’-[2-(Pyridin-4-yl)ethynyl]-2,2’:6’,2’’-terpyridine (7). CC (Al2O3, hexane/AcOEt 90 :10). Yield
1
99%. White solid from AcOEt. M.p. 2178. H-NMR: 8.72 (d, J ¼ 4, 2 H); 8.66 – 8.62 (m, 4 H); 8.60 (s,
2 H); 7.88 (J ¼ 6.1, 1.71, 2 H); 7.42 (d, J ¼ 4.65, 2 H); 7.39 – 7.35 (m, 2 H). 13C-NMR: 155.9; 155.6; 150.1;
149.4; 137.1; 132.3; 130.7; 125.8; 124.3; 123.1; 121.4; 91.7; 90.5. Anal. calc. for C22H14N4 (334.36): C 79.02,
H 4.22, N 16.76; found: C 79.22, H 4.10, N 16.46.
4’-[2-(Pyridin-3-yl)ethynyl]-2,2’:6’,2’’-terpyridine (8). CC (Al2O3 , CH2Cl2/AcOEt). Yield
1
84%.White solid from AcOEt. M.p. 1868. H-NMR: 8.81 (d, J ¼ 2, 1 H); 8.72 (ddt, J ¼ 4.6, 1, 2 H); 8.64
(s, 1 H); 8.61 (s, 2 H); 8.59 (s, 2 H); 7.90 – 7.84 (m, 3 H); 7.38 – 7.33 (m, 3 H). 13C-NMR: 155.7; 155.5;
152.5; 149.2; 138.8; 136.9; 132.6; 124.1; 123.2; 122.8; 121.3; 119.8; 90.7; 90.1. Anal. calc. for C22H14N4 · 0.5
C2H6O (357.41): C 77.29, H 4.79, N 15.67; found: C 77.62, H 4.61, N 15.15.
REFERENCES
[1] J. D. Dunitz, Pure Appl. Chem. 1991, 63, 177.
[2] M. Simard, D. Su, J. D. Wuest, J. Am. Chem. Soc. 1991, 113, 4696.
[3] M. W. Hosseini, Acc. Chem. Res. 2005, 38, 313; M. W. Hosseini, CrystEngComm 2004, 6, 318; M. W.
Hosseini, Chem. Commun. 2005, 5825.
[4] S. Mann, Nature (London) 1993, 365, 499.
[5] B. F. Abrahams, B. F. Hoskins, R. Robson, J. Am. Chem. Soc. 1991, 113, 3606.
[6] S. R. Batten, R. Robson, Angew. Chem., Int. Ed. 1998, 37, 1460; A. J. Blake, N. R. Champness, P.
Hubberstey, W.-S. Li, M. A. Withersby, M. Schrçder, Coord. Chem. Rev. 1999, 193, 117; M. W.
Hosseini, in ꢂNATO ASI Seriesꢃ, Eds. D. Braga, F. Grepiono, and G. Orpen, Serie C, Kluwer,
Dordrecht, Netherlands, 1999, V. 538, p. 181; B. Moulton, M. J. Zaworotko, Chem. Rev. 2001, 101,
1629; M. Eddaoudi, D. B. Moler, H. Li, B. Chen, T. M. Reineke, M. OꢃKeeffe, O. M. Yaghi, Acc.
Chem. Res. 2001, 34, 319; G. F. Swiergers, T. J. Malefetse, Chem. Rev. 2000, 100, 3483; C. Janiak,
Dalton Trans. 2003, 2781; L. Carlucci, G. Ciani, D. M. Proserpio, Coord. Chem. Rev. 2003, 246, 247; S.
´
Kitagawa, Angew. Chem., Int. Ed. 2004, 43, 2434; G. Ferey, C. Mellot-Draznieks, C. Serre, F.
Millange, Acc. Chem. Res. 2005, 38, 218; D. Bradshaw, J. B. Claridge, E. J. Cussen, T. J. Prior, M. J.
Rosseinsky, Acc. Chem. Res. 2005, 38, 273; G. Ferey, Chem. Soc. Rev. 2008, 37, 191.
[7] A. Jouaiti, M. W. Hosseini, A. De Cian, Chem. Commun. 2000, 1863.

2506
Helvetica Chimica Acta – Vol. 92 (2009)
[8] A. Jouaiti, M. W. Hosseini, N. Kyritsakas, Chem. Commun. 2002, 1898.
[9] A. Jouaiti, V. Jullien, M. W. Hosseini, J.-M. Planeix, A. De Cian, Chem. Commun. 2001, 1114.
[10] M. Surin, R. Samori, A. Jouaiti, N. Kyritsakas, M. W. Hosseini, Angew. Chem. 2007, 46, 245.
[11] A. Ciesielski, L. Piot, P. Samori, A. Jouaiti, M. W. Hosseini, Adv. Mater. 2009, 21, 1131.
[12] H. Takalo, J. Kankare, Acta Chem. Scand., Ser. B 1987, 41, 219.
[13] H. Takalo, P. Pasanen, J. Kankare, Acta Chem. Scand., Ser. B 1988, 42, 373.
[14] B. Schmidt, D. K. Ehlert, Tetrahedron Lett. 1998, 39, 3999.
[15] H. Nishiyama, S. Yamaguchi, M. Kondo, K. Itoh, J. Org. Chem. 1992, 57, 4306.
[16] C. Coudret, Synth. Commun. 1996, 26, 3543.
[17] L. Della Ciana, A. Haim, J. Heterocycl. Chem. 1984, 21, 607.
[18] E. C. Constable, M. D. Ward, J. Chem. Soc., Dalton Trans. 1990, 1405; B. Whittle, S. R. Batten, J. C.
Jeffrey, L. H. Rees, M. D. Ward, J. Chem. Soc., Dalton Trans. 1996, 4249.
[19] J. G. Rodriguez, R. Martin-Villamil, F. H. Cano, I. Fonseca, J. Chem. Soc., Perkin Trans. 1, 1997, 5,
709.
[20] V. Grosshenny, F. M. Romero, R. F. Ziessel, J. Org. Chem. 1997, 62, 1491.
[21] T. M. Fasina, J. C. Collings, D. P. Lydon, D. Albesa-Jove, A. S. Batsanov, J. A. K. Howard, P. Nguyen,
M. Bruce, A. J. Scott, W. Clegg, S. W. Watt, C. Viney, B. T. Marder, J. Mater. Chem. 2004, 14, 2395.
Received March 13, 2009