Tetrathiafulvalene-containing pseudorotaxanes formed between dibenzylammonium salts and crown ethers

Article abstract of DOI:10.1016/S0040-4020(00)01062-0

The synthesis of two tetrathiafulvalene (TTF) derivatives, one carrying arms incorporating four dibenzylammonium centers and the other encompassing two annulated crown ether rings - i.e., hydrogen bond donor and acceptor functions, respectively, is described. In the presence of macrocyclic polyethers - e.g., DB24C8 and BPP34C10 - and dibenzylammonium hexafluorophosphate, these two TTF derivatives form pseudorotaxanes as evidenced by ¹H NMR spectroscopy, mass spectrometry, and differential pulse voltammetry.

Full text of DOI:10.1016/S0040-4020(00)01062-0

TETRAHEDRON
Pergamon
Tetrahedron 57 (2001) 947±956
Tetrathiafulvalene-containing pseudorotaxanes formed between
dibenzylammonium salts and crown ethers
Peter R. Ashton,a Jan Becher,b,p Matthew C. T. Fyfe,c Mogens Brùndsted Nielsen,b,c,²
J. Fraser Stoddart,c,p Andrew J. P. Whited and David J. Williamsd,p
aSchool of Chemistry, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
bDepartment of Chemistry, University of Southern Denmark (Odense University), Campusvej 55, DK-5230 Odense M, Denmark
cDepartment of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095, USA
dDepartment of Chemistry, Imperial College, South Kensington, London SW7 2AY, UK
Received 21 September 2000; accepted 3 November 2000
AbstractÐThe synthesis of two tetrathiafulvalene (TTF) derivatives, one carrying arms incorporating four dibenzylammonium centers and
the other encompassing two annulated crown ether ringsÐi.e., hydrogen bond donor and acceptor functions, respectively, is described. In the
presence of macrocyclic polyethersÐe.g., DB24C8 and BPP34C10Ðand dibenzylammonium hexa¯uorophosphate, these two TTF
derivatives form pseudorotaxanes as evidenced by 1H NMR spectroscopy, mass spectrometry, and differential pulse voltammetry.
q 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
polyethers. Thus, the dibenzylammonium ion 11 and
dibenzo[24]crown-8 (DB24C8) form
a 1:1 complex
[1´DB24C8]1Ðin both the solution and solid states4Ð
which is stabilized for the most part by hydrogen bonds
between the electron-donating oxygen atoms of DB24C8
and (i) the NH21 protons ([1N±H´´´O]) and (ii) the benzylic
methylene protons ([C±H´´´O]) of 11.
The ef®cient p-electron donor, tetrathiafulvalene (TTF), has
found wide application in many areas of macrocyclic1 and
supramolecular2 chemistry. Nowadays, synthetic protocols
are available for constructing elaborate multiply-bridged
TTF macrocycles, some of which are able to form host±
guest complexes with electron-de®cient compounds as a
result of donor-acceptor interactions. Also, considerable
effort has been devoted3 to employing hydrogen bonding
for self-assembling supramolecular systems and networks
based on TTF. Thus, the promotion of short intermolecular
distances between TTF units in the crystal stacking is of
crucial importance for the development of organic con-
ductors. Moreover, the ability of TTF to switch reversibly
between three redox states (0, 11, 12) upon oxidation/
reduction, at potentials which are in¯uenced by the presence
of interacting molecules/ions, makes it a very good
candidate for being incorporated into supramolecular
assemblies.2 Consequently, we decided to explore the
ability of hydrogen bonds to govern the formation of TTF
pseudorotaxanes and other supermolecules with interwoven
architectures, employing the recognition motif that exists
between secondary dialkylammonium ions and macrocyclic
Keywords: crown ethers; dibenzylammonium salts; pseudorotaxanes; self-
assembly; tetrathiafulvalene.
p Corresponding authors. Tel. 1310-206-7078; fax: 1310-206-1843;
e-mail: stoddart@chem.ucla.edu
Present address: Laboratorium fuÈr Organische Chemie, Eidgenossische
²
È
Technische Hochschule (ETH), Universitatsstrasse 16, CH-8092 Zurich,
Switzerland.
È
È
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)01062-0

948
P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
Scheme 1. Synthesis of Boc-protected dibenzylamine building block containing a benzylic bromide.
To date, a number of pseudorotaxane superstructures
involving secondary dialkyl- or dibenzylammonium ions
2. Results and discussion
and crown ethers, such as DB24C8 or bis-p-phenylene[34]-
crown-10 (BPP34C10), have been reported,4,5 including
both singly- and multiply-stranded pseudorotaxanes, in
addition to interlocked molecular compounds with inter-
woven architectures formed from branched oligo-
ammonium cations. Thus, by employing a porphyrin as
the central core, an analog resembling the photosynthetic
special pair has been self-assembled as a 412 interwoven
complex.5h
2.1. Synthesis
Retrosynthetic analyses suggest 4±8 as possible presursors
for 241 and 3. The cyanoethyl-protected TTF-thiolate 4 and
its `half-unit', 1,3-thiole-2-thione (5), are easily deprotected
using CsOH as base.6 The thiolate functions, which are
generated in this fashion, can then be realkylated with the
alkylating reagents 6±8.
We now describe the ®rst examples of such supramolecular
systems containing the redox responsive unit TTF. Com-
bining TTF with the functions in either 11 or DB24C8
leads to the two complementary compounds 241 and 3,
i.e., a TTF tetracation and a TTF-catechol biscrown. The
syntheses of these target molecules are described and their
abilities to form complexes with DB24C8, BPP34C10 and
11, in turn, are discussed.
The synthesis of the bromide 6 is summarized in Scheme 1.
Firstly, the ester 95f was reduced with LiAlH4 according to a
Scheme 2. Synthesis of TTF-tetracation.

P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
949
Scheme 3. Synthesis of TTF-biscrown.
modi®ed literature procedure,5f generating the alcohol 10,
which was subsequently treated with PPh3/CBr4, yielding 6.
in Scheme 3. Firstly, the diiodide 8, obtained from the
ditosylate 7 by a Finkelstein reaction with NaI, was reacted,
under high-dilution conditions, with the in situ generated
bisthiolate of 5, affording the macrocycle 13. This 1,3-
dithiole-2-thione was converted into the 1,3-dithiole-2-one
14 by treatment of 13 with Hg(OAc)2. Subsequent coupling
of 14 in the presence of P(OEt)3 afforded 3 in good yield.
The bromide 6 was then reacted (Scheme 2) with the tetra-
thiolate (TTFTT) produced in situ from 4, by adding
4.5 equiv. of cesium hydroxide to the reaction mixture.
From this mixture, the TTF-compound 11, containing four
protected amine functions, was obtained. The Boc groups
were removed with tri¯uoroacetic acid (TFA) in chloro-
form, affording7 the tetra-amine 12. Although protonation
of the central fulvene bond upon the acid treatment is very
likely to have occurred, as evidenced by the dark red colora-
tion of the solution, when treated with base during the work-
up, deprotonation of all the ammonium centers and the TTF
occurs.8 Finally, the tetra-amine was protonated with 3 M
HCl(aq), before counterion exchange with saturated
aqueous NH4PF6 yielded the salt 2´4PF6.
3. Complexation studies
1
3.1. H NMR spectroscopy
Although the salt 2´4PF6 is insoluble in dichloromethane, it
can be extracted into this solvent containing BPP34C10.
1
According to the H NMR spectrum, the crown is able to
extract ca. 0.5 equiv. of the ammonium salt. This 1:2
stoichiometry is in accordance with the principle of
maximal site occupancy,10 i.e., all the binding sites in
The synthesis9 of the biscrown ether compound 3 is outlined
1
Figure 1. H NMR spectra (400 MHz) of (a) BPP34C10 in CD3CN; (b) 2´4PF6 in CD3CN; and (c) 2´4PF6 in CD2Cl2 containing 2 equiv. of BPP34C10.

950
P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
Figure 2. 1:2 and 2:4 complexes of 2´4PF6 and BPP34C10.
1
1
2´4PF6 and BPP34C10 are occupied. Indeed, from an
inspection of the 1H NMR spectrum (Fig. 1) it would appear
that none of the free components are present. The stoichio-
metry corresponds (Fig. 2) to the formation of either 1:2 or
2:4 complexes. The formation of polymeric arrays seem
unlikely in solution on the basis of entropy considerations.
the exchangeable NH2 protons in the H NMR spectrum
(Fig. 1b) of 2´4PF6 disappeared upon addition of D2O, thus
con®rming its assignment.
By comparison of 1H NMR spectra (Fig. 3), the biscrown 3
is clearly able to extract 2 equiv. of 1´PF6 into CH2Cl2 as
expected. However, peaks are evident in the spectrum (Fig.
3c) for both complexed and uncomplexed components,
con®rming that the equilibrium illustrated in Fig. 4 is
slow on the H NMR timescale. Upon complexation, the
singlet observed for the NCH2 protons is not only shifted
down®eld (by 10.45 ppm) but also takes on a multiplet
character by virtue of coupling to the NH2 protons, a
phenomenon which is observed5b when they are encircled
by DB24C8.
Upon complexation with BPP34C10, a signal centered on d
4.5 for eight NCH2 protons in 2´4PF6 was observed (Fig. 1c),
i.e., it had been shifted down®eld from the signal for the
other eight NCH2 protons, which were identi®ed to resonate
1
1
at ca. 3.7 ppm (in the OCH2/SCH2 region) in the H±1H
1
1
COSY spectrum as a result of scalar coupling to the NH2
protons. Complexation to form
a
supermolecule is
supported, not only by the down®eld shift of the NCH2
signal, but also by the broad peaks observed for most of
the other signals in the H NMR spectrum. The signal for
The dibenzylammonium ion 11 is also in slow exchange on
1
Figure 3. 1H NMR spectra (400 MHz) of (a) 1´PF6 in CD3CN; (b) 3 in CD2Cl2; and (c) 311´PF6 (2 equiv.) in CD2Cl2. Notation: cˆcomplexed, uˆuncom-
plexed.

P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
951
Figure 4. The equilibria between 11 and 3 in solution (dichloromethane).
Figure 5. Formation of pseudorotaxane between 13 and 1´PF6.
the 1H NMR timescale (400 MHz) with the crown 13 in the
formation of their 1:1 complex (Fig. 5). This observation
made possible the determination of the association constant
(Kaˆ2750 M21) for the formation of this complex in CD2Cl2
at 300 K. This Ka value can be compared with that5a of
27000 M21 when 13 is replaced by DB24C8. Not sur-
prisingly, the replacement of two oxygen atoms in the
24C8 constitution by two sulfur atoms reduces the binding
constant by an order of magnitude.
TMT±TTF (in CH2Cl2). This observation indicates that
the four cationic centers are no longer in¯uencing the oxi-
dation of TTF. When 2´4PF6 was extracted into a solution of
BPP34C10 in CH2Cl2, the ®rst and second oxidations
occurred at values even lower than those observed for
TMT±TTF. Lowering of the ®rst potential may be
explained by the favorable formation of a p-dimer between
two radical cations in close proximity, hence indicating
formation of the 2:4 complex. However, an explanation
for the decrease in the second potential is less obvious.
3.2. Electrochemistry
In conclusion, formation of complexes between 2´4PF6 and
BPP34C10 or DB24C8 cancels the electrostatic repulsion
between the mono/dioxidized TTF and the four ammonium
centers. Adding 1´PF6 (ca. 70 equiv.) to the biscrown 3 (in
CH2Cl2/MeCN 9:1) does not alter the oxidations of the TTF
unit all that much. Thus, inclusion of two ammonium
centers in the two crown cavities does not affect the TTF
unit. This observation is in agreement with the ®nding that
complexation of 2´4PF6 cancels the electrostatic repulsion
from the ammonium centers, i.e., when included in the poly-
ether crown, the dispersed positive charge of the ammonium
group does not affect the redox behavior of the TTF unit.
The redox potentials of 2´4PF6 and its complexes with
BPP34C10 and DB24C8 were determined by differential
pulse voltammetry and are listed in Table 1. The ®rst and
second potentials of the ammonium salt are signi®cantly
shifted relative to tetramethylthiotetrathiafulvalene
1
2
(TMT±TTF), DE1/2 ˆ10.08 V, DE1/2 ˆ10.13 V (in
MeCN). These shifts can be explained by electrostatic
repulsion between the charges generated on 241 upon oxi-
dation and the four positive charges already present in the
tetracations. Adding a large excess of DB24C8 to 2´4PF6 in
MeCN did not alter the potentials to any signi®cant extent.
However, in CH2Cl2, where the formation of 1:4 complexes
with DB24C8 is expected to occur to a higher degree than in
MeCN, the redox potentials are comparable to those of
3.3. Mass spectrometry
The complexes were also studied in the gas phase employ-
ing fast atom bombardment (FAB) and electrospray (ES)
mass spectrometry. Although the ES-MS of a mixture
between 2´4PF6 and BPP34C10 showed peaks which can
be assigned (Table 2) to 1:1 and 1:2 complexes, no evidence
for a 2:4 complex was obtained. The ES-MS of a mixture of
1´PF6 and 3 reveals peaks corresponding to occupation of
either one or both crown ether units of 3 by 11 ions.
Table 1. Differential pulse data for the oxidation of TTF in the presence or
absence of ammonium centers (reference electrode: Ag/AgCl; working and
counter electrodes: Pt. Supporting electrolyte: n-Bu4NPF6 (0.1 M))
Compound
Solvent
CH2Cl2
MeCN
MeCN
MeCN
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2/MeCN 9:1
CH2Cl2/MeCN 9:1
E1/21/V
E1/22/V
TMT±TTF
TMT±TTF
0.56
0.50
0.58
0.60
0.58
0.51
0.53
0.48
0.49
0.91
0.75
0.88
0.89
0.90
0.84
0.76
0.71
0.69
2´4PF6
2´4PF61DB24C10 (excess)
2´4PF61DB24C10 (excess)
2´4PF61BPP34C10 (1:2)a
3.4. X-Ray crystallography
3
3
311´PF6 (excess)
Although there is evidence of complexation occurring in
solution, the crystals produced11 from crystallizations of
both 3 and 13 carried out from solutions containing the
a Extraction of 2´4PF6 into a CH2Cl2 solution of BPP34C10.

952
P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
Table 2. Peaks (m/z) assigned to complexes in the mass spectra
1:1 Complex [M2zPF6]z1
1:2 Complex [M2zPF6]z1
1267 (zˆ2)a, 796.3 (zˆ3)a, 561 (zˆ4)a
702 (zˆ2)a
2´4PF6´BPP34C10
1´PF6´13
1´PF6´3
999 (zˆ2)a, 617.7 (zˆ3)a
734 (zˆ1)a,b
1206 (zˆ1)a,b
a ES-MS.
b FAB-MS.
salt 1´PF6 were found to be free of any complexed
cations 11.
3. The molecules stack along the crystallographic b
direction with negligible p±p overlap of either the
1,3-dithiole-2-thione or catechol rings; the mean interplanar
separations are 3.64 and 3.31 A, respectively, but with
Ê
centroid±centroid separations of 5.03 A in each case.
Ê
The biscrown ether 3 is centrosymmetric, having a planar
TTF core with the dithio-24-crown-8 components adopting
twisted self-®lling conformations (Fig. 6). The molecules
form continuous p±p stacks (Fig. 7) with the dominant
intermolecular interactions being between the TTF compo-
4. Conclusions
nents (mean planar separation,12 3.63 A) with a signi®cantly
Ê
weaker interaction between the catechol rings (mean inter-
Ê
planar separation 3.49 A, but with a ring centroid´´´ring
New functionalized TTF derivatives have been synthesized
and used for the construction of hydrogen bonded multi-
component pseudorotaxanes, as evidenced by 1H NMR
spectroscopy, mass spectrometry and differential pulse
voltammetry. However, these supramolecular architectures
dissociate on crystallization. The high propensity for TTF
units to form p±p stacks in the solid state is presumably the
Ê
centroid distance of 4.98 A).
The crystal structure (Fig. 8) of the crown ether 13 shows
the dithia-24-crown-8 portion of the macrocycle to have a
similar twisted self-®lling conformation to that observed in
Figure 6. The solid state structure of 3.

P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
953
Figure 7. The p±p stacking of the TTF units in the structure of 3.
Figure 8. The solid state structure of 13.
driving force for the decomplexation of the 1:2 complex
formed in solution between the bis-crown ether 3 and the
dibenzylammonium ion 11. Supramolecular arrays, which
5. Experimental
5.1. General methods
1
combine (1) the recognition of substituted NH2 centers
with macrocycles based on 24-crown-8 constitutions with
(2) the ability of TTF units to form donor±acceptor
complexes with electron-de®cient species, represent a
worthwhile goal for crystal engineers to pursue in the future.
All reactions were carried out under an atmosphere of dry
nitrogen. THF was distilled from sodium/benzophenone;
methanol was distilled from Mg and I2; DMF was allowed
Ê
to stand over molecular sieves (4 A) for at least 3 days

954
P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
before use; acetonitrile was distilled from CaH2. Melting
points were determined on a Thomas Hoover Melting
Point Apparatus and are uncorrected. Elemental analyses
were performed by Quantitative Technologies Inc. NMR
spectra were recorded on a Bruker ARX400 (400 MHz)
spectrometer using the deuterated solvent as the lock and
the residual solvent as internal reference. Fast atom
bombardment mass spectra (FAB) were obtained from a
ZAB-SE instrument. Electrospray mass spectra were
obtained from a VG ProSpec mass spectrometer ®tted
with an electrospray source and using acetonitrile as the
mobile phase at a ¯ow rate of 20 mL min21. Differential
pulse voltammetry was measured on an Autolab,
PGSTAT10 potentiostat (ECO CHEMIE BV); Bu4NPF6
was used as supporting electrolyte; counter and working
electrodes were made of Pt, and the reference electrode
was Ag/AgCl. Notation: uˆuncomplexed, cˆcomplexed;
cat.ˆcatechol.
SCH2), 3.60±3.66 (m, 16H, OCH2), 3.70±3.72 (m, 8H,
OCH2), 3.82 (t, Jˆ4.5 Hz, 8H, OCH2), 4.09 (t, Jˆ4.5 Hz,
8H, OCH2), 6.87 (s, 8H, cat.); FABMS: m/zˆ1009
[M1H1]. Anal. calcd for C42H56O12S8: C 49.98, H 5.59;
found: C 49.97, H 5.55.
5.1.3. N-(tert-Butoxycarbonyl)-N-benzyl-4-(bromomethyl)-
benzylamine (6). To a solution of 10 (2.92 g, 8.9 mmol) in
dry THF (250 mL) was added CBr4 (6.19 g, 18.7 mmol.
Then PPh3 (6.07 g, 23.1 mmol) was added in small portions
during 1 h. The reaction mixture was left overnight with
stirring, whereupon it was concentrated in vacuo. The
residue was subjected to column chromatography
[hexanes/EtOAc 5:1], affording 6 (2.97 g, 86%) as a colour-
1
less oil. H NMR (CDCl3): dˆ1.49 (s, 9H, CH3), 4.33 and
4.41 (two br, both 2H, NCH2), 4.50 (s, 2H, BrCH2), 7.12±
7.37 (m, 9H, Ph); FABMS: m/zˆ390 [M1H]1; HR-
FABMS: C20H24NO2Br requires m/zˆ390.1069 [M1H]1;
found 390.1065. Anal. calcd for C20H24NO2Br: C 61.54, H
6.20, N 3.59; found: C 61.57, H 6.22, N 3.54.
5.1.1. 2,3,6,7-Tetrakis{[4-(N-benzylammoniummethyl)-
phenyl]methylthio}tetrathiafulvalene tetrakis(hexa¯uoro-
phosphate) (2´4PF6). A solution of 11 (0.260 g, 0.17 mmol)
in CHCl3 (13 mL) was stirred with tri¯uoroacetic acid
(TFA) (0.7 mL) for 2 days (dark red solution). Then the
solution was diluted with CHCl3 (100 mL) and washed
with 1 M NaOH (2£50 mL). The organic phase was dried
(MgSO4) and concentrated in vacuo to afford 12 (0.177 g,
91%) as an orange oil, which was used without further
puri®cation. 1H NMR (CDCl3): dˆ2.25 (br, 4H, NH),
3.75 (s, 16H, NCH2), 3.87 (s, 8H, SCH2), 7.09±7.32 (m,
36H, Ph); FABMS: m/zˆ1168 [M1]. 12 (0.158 g,
0.14 mmol) was dissolved in THF (3 mL) and MeOH
(20 mL), whereupon 3 M HCl was added with stirring to
alter the pH to ca. 1. After 2 1/2 h the resulting suspension
was concentrated in vacuo. The residue was dissolved in
MeNO2 (100 mL) and sat. aqueous NH4PF6 (25 mL). The
phases were partitioned and the organic phase washed with
sat. aqueous NH4PF6 (25 mL) and water (5£100 mL). Then
it was concentrated in vacuo to afford the tetrakisammo-
5.1.4. 1,2-Bis(2-(2-(2-iodoethoxy)ethoxy)ethoxy)benzene
(8). A solution of 7 (4.97 g, 7.27 mmol) and NaI (4.36 g,
29.1 mmol) in acetone (150 mL) was re¯uxed overnight.
Then the solution was ®ltered and concentrated in vacuo.
CH2Cl2 (200 mL) was added, and the solution was washed
with water (2£100 mL) and dried (MgSO4). After removing
the solvent in vacuo the residue was subjected to column
chromatography [CH2Cl2/EtOAc 10:1], affording 8 (3.69 g,
1
85%) as a yellow oil. H NMR (CDCl3): dˆ3.26 (t, Jˆ
6.9 Hz, 4H, ICH2), 3.67±3.70 (m, 4H, OCH2), 3.73±3.78
(m, 8H, OCH2), 3.87 (t, Jˆ5.0 Hz, 4H, OCH2), 4.18 (t,
Jˆ5.0 Hz, 4H, OCH2), 6.92 (2£s, 4H, cat.); 13C NMR
(CDCl3): dˆ2.96 (ICH2), 68.87 (OCH2), 69.88 (OCH2),
70.29 (OCH2), 70.81 (OCH2), 71.97 (OCH2), 114.93
(cat.), 121.66 (cat.), 148.96 (cat.); FABMS: m/zˆ594
[M1]; HR-FABMS: C18H28I2O6 requires m/zˆ593.9975
[M1]; found: 593.9974.
1
nium salt 2´4PF6 as an orange solid (0.232 g, 98%). H
5.1.5. N-(tert-Butoxycarbonyl)-N-benzyl-4-hydroxymethyl-
benzylamine (10). A solution of N-(tert-butoxycarbonyl)-N-
benzyl-4-carbomethoxybenzylamine 9 (8.98 g, 25.2 mmol) in
anhydrous THF (115 mL) was added dropwise to a stirred
suspension of LiAlH4 (1.81 g, 47.6 mmol) in anhydrous THF
(85 mL) over a period of 15 min. The reaction mixture was
stirred for 21 h at 208C, before being treated with H2O
(1.8 mL), followed successively by 5 M NaOH (1.8 mL) and
more H2O (5.2 mL). The resulting suspension was stirred for
an additional 5 min., before being ®ltered through a thin pad of
Celite. The solution was concentrated under reduced pressure,
and the residue partitioned between CH2Cl2 (200 mL) and H2O
(200 mL), with the aqueous phase being extracted further with
CH2Cl2 (2£200 mL). The combined organic extract was
washed with H2O (200 mL), before being dried (Na2SO4).
The solution was ®ltered, and the solvent evaporated in
vacuo to yield a clear oil (8.09 g, 98%), which was used with-
out further puri®cation. A small portion of this oil was puri®ed
by column chromatography [n-C6H14/EtOAc 3:2] to provide
the pure title compound 10. Spectroscopic data in agreement
with Ref. 5f.
NMR (CD3CN): dˆ3.99 (br s, 8H, SCH2), 4.18 (s, 8H,
NCH2), 4.20 (s, 8H, NCH2), 7.08 (br, 8H, NH2), 7.32±
7.47 (m, Ph, 36H); FABMS: m/zˆ1169 [M2PF6±
3HPF6]1, 1314 [M23HPF6]1, 1462 [M22PF6]1, 1607
[M2PF6]1; ESMS: m/zˆ1169 [M2PF6±3HPF6]1, 1315
[M22HPF6±PF6]1, 1461 [M2HPF6±PF6]1, 1607 [M2
PF6]1. Anal. calcd for C66H68F24P4S8: C 45.20, H 3.91, N
3.19; found: C 45.40, H 4.00, N 3.27.
5.1.2. 2,3,6,7-Bis[benzene-1,2-diyldioxybis(ethane-1,2-diyl)-
dioxybis(ethane-1,2-diyl)dioxybis(ethane-1,2-diyl)bisthio]-
tetrathiafulvalene (3).
A solution of 14 (0.200 g,
0.38 mmol) in toluene (4 mL) and triethyl phosphite
(8 mL) was heated at 1208C for 4 h. The orange product
precipitated upon cooling the solution on ice, but to obtain
total precipitation, methanol (50 mL) was added. The solid
was ®ltered and washed with methanol (50 mL). Recrystal-
lization from acetonitrile afforded 3 (0.142, 73%) as an
1
orange solid. Mp 152.5±1548C. H NMR (CDCl3): dˆ
3.02 (t, Jˆ5.8 Hz, 8H, SCH2), 3.66±3.71 (m, 16H,
OCH2), 3.79±3.81 (m, 8H, OCH2), 3.90 (t, Jˆ4.5 Hz, 8H,
OCH2), 4.15 (t, Jˆ4.5 Hz, 8H, OCH2), 6.89 (2£s, 8H,
cat.); 1H NMR (CD2Cl2): dˆ2.99 (t, Jˆ6.2 Hz, 8H,
5.1.6. 2,3,6,7-Tetrakis{[4-(N-(tert-butoxycarbonyl)-N-
benzylaminomethyl)-phenyl]-methylthio}tetrathia-fulva-

P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
955
lene (11). To a solution of 4 (0.75 g, 1.4 mmol) in DMF
(120 mL) was added a solution of CsOH´H2O (1.03 g,
6.1 mmol) in MeOH (15 mL) during 10 min. The mixture
was stirred for 1 h, whereupon 6 (2.40 g, 6.1 mmol) in DMF
(20 mL) was added. After stirring for 3 h, the mixture was
concentrated in vacuo. The product was dissolved in CH2Cl2
(200 mL), washed with water (2£200 mL), and dried
(MgSO4). After ®ltration, the solution was boiled with
active charcoal for 5 min, ®ltered and concentrated in
vacuo. The product was subjected to column chroma-
tography [(i) CH2Cl2 elutes excess 7, (ii) CH2Cl2/EtOAc
10:1], affording 11 (1.69 g, 78%) as an orange semicrystal-
OCH2), 3.74 (t, Jˆ6.1 Hz, 4H, OCH2), 3.79±3.81 (m, 4H,
OCH2), 3.90 (t, Jˆ4.5 Hz, 4H, OCH2), 4.16 (t,
Jˆ4.5 Hz, 4H, OCH2), 6.90 (2£s, 4H, cat.); 13C NMR
(CDCl3): dˆ36.21 (SCH2), 69.25 (OCH2), 69.71 (OCH2),
69.90 (OCH2), 70.77 (OCH2), 70.91 (OCH2), 114.32 (cat.),
121.53 (cat.), 127.64 (CvC), 148.91 (cat.), 189.66 (CvO);
FABMS: m/zˆ520 [M1]; HR-FABMS: C21H28O7S4
requires m/zˆ520.0718 [M1]; found: 520.0711. Anal.
calcd for C21H28O7S4: C 48.44, H 5.42; found: C 48.35, H
5.30.
1
5.2. Complex formed between 2´4PF6 and BPP34C10
line oil. H NMR (CDCl3): dˆ1.49 (s, 36H, CH3), 3.89 (s,
8H, SCH2), 4.39 and 4.42 (two br, both 8H, NCH2), 7.09±
7.35 (m, 36H, Ph); FABMS: m/zˆ1570 [M12H]1. Anal.
calcd for C86H96N4O8S8: C 65.78, H 6.16, N 3.57; found: C
65.33, H 6.18, N, 3.44.
The salt 2´4PF6 was extracted into a solution of BPP34C10
(ca. 20 mg) in CD2Cl2 (ca. 1 mL), until no more could be
1
dissolved. The solution was ®ltered and subjected to H
NMR spectral measurement, and the ratio between 2´4PF6
and BPP34C10 was determined from the integrals
5.1.7. 4,5-[Benzene-1,2-dioxybis(ethane-1,2-diyl)dioxy-
bis(ethane-1,2-diyl)dioxybis(ethane-1,2-diyl)bisthio]-1,3-
dithiole-2-thione (13). To a solution of 5 (0.777 g,
2.55 mmol) in MeCN (40 mL) and DMF (10 mL) was drop-
wise added a solution of CsOH´H2O (0.900 g, 5.36 mmol) in
methanol (15 mL) over 10 min. After stirring for 1 h, this
solution and a solution of 8 (1.516 g, 2.55 mmol) in MeCN
(65 mL) were added simultaneously to a solution of MeCN
(100 mL) during 11 h under high dilution conditions by
means of a two-syringe perfusor pump. Stirring was con-
tinued for an additional 2 h, whereupon the reaction mixture
was concentrated in vacuo. Then CH2Cl2 (200 mL) was
added, and the solution was washed with water (200 mL),
dried (MgSO4), and concentrated in vacuo. Column
chromatography [CH2Cl2/EtOAc 5:1] afforded 13
(0.657 g, 48%) as a yellow solid. Mp. 99±1008C. 1H
NMR (CDCl3): dˆ3.08 (t, Jˆ5.9 Hz, 4H, SCH2), 3.66±
3.68 (m, 4H, OCH2), 3.75 (t, Jˆ5.9 Hz, 4H, OCH2), 3.78±
3.80 (m, 4H, OCH2), 3.90 (t, Jˆ4.5 Hz, 4H, OCH2), 4.16 (t,
Jˆ4.5 Hz, 4H, OCH2), 6.90 (2£s, 4H, cat.); 1H NMR
(CD2Cl2): dˆ3.06 (t, Jˆ6.0 Hz, 4H, SCH2), 3.61±3.63
(m, 4H, OCH2), 3.71±3.73 (m, 8H, OCH2), 3.83 (t, Jˆ
4.5 Hz, 4H, OCH2), 4.10 (t, Jˆ4.5 Hz, 4H, OCH2), 6.88
(s, 4H, cat.); 13C NMR (CDCl3): dˆ36.39 (SCH2), 69.24
(OCH2), 69.71 (OCH2), 69.93 (OCH2), 70.79 (OCH2), 70.93
(OCH2), 114.35 (cat.), 121.53 (cat.), 136.77 (CvC), 148.91
(cat.), 211.20 (CvS); FABMS: m/zˆ538 [M12H]1; HR-
FABMS: C21H28O6S5 requires m/zˆ536.04895 [M1H1];
found: 536.0493. Anal. calcd for C21H28O6S5: C 46.99, H
5.26; found: C 46.94, H 5.18.
1
(1:1.8,1:2). H NMR (CD2Cl2): dˆ3.23 (br s), 3.33 (br
s), 3.64 (br s), ,3.7 (very br, position determined by
COSY, NCH2), 3.94 (br s) [3.23±3.94 (80H, SCH2, OCH2,
NCH2)], 4.47 (br s, 8H, NCH2), 6.74 (br s), 6.84 (br s), 6.84±
7.47 (br), 7.47 (m), 7.55 (s), 7.56 (s), 7.60 (br s, NH2) [6.74±
7.60 (60H, Ph, OPhO, NH2)]; ESMS: m/zˆ561 [1:2 com-
plex24PF6]41, 617.7 [1:1 complex23PF6]31, 796.3 [1:2
complex23PF6]31, 999 [1:1 complex22PF6]21, 1267 [1:2
complex22PF6]21
.
5.3. Complex formed between 3 and 1´PF6
The salt 1´PF6 was extracted into a solution of 3 in CD2Cl2
until no more could be dissolved. The solution was ®ltered
and subjected to 1H NMR, and the ratio between 3 and 1´PF6
1
was determined from the integrals (1:2.1,1:2). H NMR
(CD2Cl2): dˆ2.98 (br, ca. 1H, SCH2 u), 3.15 (t, Jˆ4.8 Hz,
ca. 7H, SCH2 c), 3.42±3.43 (m), 3.58 (t, Jˆ2.8 Hz), 3.64±
3.66 (m), 3.81 (t, Jˆ4.8 Hz) [3.42±3.81 (32H, OCH2 u/c)],
3.93 (t, Jˆ2.8 Hz, 7H, OCH2 c), 4.11 (br, ca. 1H, OCH2 u),
4.26 (s, ca. 1H, NCH2 u), 4.71 (t, Jˆ6.7 Hz, ca. 7H, NCH2
c), 6.61 (dd, Jˆ3.6 and 6.0 Hz, ca. 3.5H, cat. c), 6.84 (dd,
Jˆ3.5 and 6.0 Hz, ca. 3.5H, cat. c), 6.89 (br, ca. 1H, cat. u),
7.22 (t, Jˆ3.1 Hz, ca. 10H, Ph c), 7.37±7.43 (m, ca. 10H, Ph
u/c), 7.80 (br, 4H, NH2); FABMS: m/zˆ1206 [1:1 complex-
PF6]1; ESMS: m/zˆ702 [1:2 complex22PF6]21, 1206 [1:1
complex2PF6]1.
5.4. Complex formed between 13 and 1´PF6
5.1.8. 4,5-[Benzene-1,2-dioxybis(ethane-1,2-diyl)dioxy-
bis(ethane-1,2-diyl)dioxybis(ethane-1,2-diyl)bisthio]-1,3-
dithiole-2-one (14). To a solution of 13 (0.524 g,
0.98 mmol) in CHCl3 (75 mL) and glacial acetic acid
(30 mL) was added Hg(OAc)2 (0.778 g, 2.44 mmol), where-
upon the solution was stirred for 3 h. Then it was ®ltered on
Celite, and the Celite layer was rinsed with CHCl3
(100 mL). The ®ltrate was washed with NaHCO3 (aq)
until no more CO2-evolution was observed, and then ®nally
with water (200 mL). The organic phase was dried
(MgSO4), and concentrated in vacuo. Column chroma-
tography [CH2Cl2/EtOAc 5:1] afforded 14 (0.373 g, 73%)
Concentrations in CD2Cl2: [13]ˆ[1´PF6]ˆ0.0097 M. 1H
NMR (CD2Cl2): dˆ3.06 (t, Jˆ5.7 Hz, ca. 0.7H, SCH2 u),
3.20 (t, Jˆ5.1 Hz, ca. 3.3H, SCH2 c), 3.46±3.48 (m), 3.58±
3.62 (m), 3.68±3.71 (m), 3.83±3.86 (m) [3.46±3.86 (16H,
OCH2 c/u)], 3.94 (t, Jˆ3.8 Hz, ca. 3.3H, OCH2 c), 4.11 (br t,
ca. 0.7H, OCH2 u), 4.28 (s, ca. 0.7H, NCH2 u), 4.71 (t, Jˆ
6.9 Hz, ca. 3.3H, NCH2 c), 6.61 (dd, Jˆ3.5 and 6.0 Hz, ca.
1.65H, cat. c), 6.85 (dd, Jˆ3.5 and 6.0 Hz, ca. 1.65H, cat. c),
6.89 (br s, ca. 0.7H, cat. u), 7.23±7.25 (m, ca. 4.8H, Ph c),
7.38±7.41 (m), 7.45 (br s) [7.38±7.45 (ca. 5.2H, Ph c/u)],
7.88 (br, 2H, NH2); FABMS: m/zˆ734 [M2PF6]1; ESMS:
m/zˆ734 [M2PF6]1.
1
as a white solid. Mp 101.5±102.58C. H NMR (CDCl3):
dˆ3.05 (t, Jˆ6.1 Hz, 4H, SCH2), 3.66±3.68 (m, 4H,

956
P. R. Ashton et al. / Tetrahedron 57 (2001) 947±956
Menzer, S.; Schiavo, C.; Stoddart, J. F.; White, A. J. P.;
Williams, D. J. Chem. Eur. J. 1998, 4, 1523.
References
6. Simonsen, K. B.; Svenstrup, N.; Lau, J.; Simonsen, O.;
Mùrk, P.; Kristensen, G. J.; Becher, J. Synthesis 1996, 3, 407.
7. For alternative procedures for preparing amino-functionalized
tetrathiafulvalene derivatives, see: (a) Bertho, F.; Robert, A.;
Batail, P.; Robin, P. Tetrahedron 1990, 46, 433. (b) Fabre,
1. For a review on TTF macrocycles, see: Nielsen, M. B.;
Becher, J. Liebigs Ann./Recueil 1997, 2177.
2. For reviews on TTF in supramolecular chemistry, see:
(a) Jùrgensen, T.; Hansen, T. K.; Becher, J. Chem. Soc. Rev.
1994, 23, 41. (b) Bryce, M. R. Adv. Mater. 1999, 11, 11.
(c) Nielsen, M. B.; Lomholt, C.; Becher J. Chem. Soc. Rev.
2000, 29, 153.
Â
J.-M.; Garõn, J.; Uriel, S. Tetrahedron 1992, 48, 3983.
(c) Parg, R. P.; Kilburn, J. D.; Petty, M. C.; Pearson, C.;
Ryan, T. G. Synthesis 1994, 613. (d) Le Hoerff, T.;
Lorcy, D.; Floner, D.; Moinet, C.; Bittner, S.; Mingotaud, C.;
Delhaes, P.; Robert, A. J. Mater. Chem. 1995, 5, 1589.
(e) Binet, L.; Fabre, J.-M. Synthesis 1997, 1179.
Â
3. (a) Blanchard, P.; Salle, M.; Duguay, G.; Jubault, M.;
Gorgues, A. Tetrahedron Lett. 1992, 33, 2685. (b)
Batsanov, A. S.; Bryce, M. R.; Cooke, G.; Heaton, J. N.;
Howard, J. A. K. J. Chem. Soc., Chem. Commun. 1993,
1701. (c) Neilands, O.; Belyakov, S.; Tilika, V.; Edzina, A.
J. Chem. Soc., Chem. Commun. 1995, 325. (d) Batsanov,
A. S.; Svenstrup, N.; Lau, J.; Becher, J.; Bryce, M. R.;
Howard, J. A. K. J. Chem. Soc., Chem. Commun. 1995,
1201. (e) Moore, A. J.; Bryce, M. R.; Batsanov, A. S.;
Heaton, J. N.; Lehmann, C. W.; Howard, J. A. K.;
Robertson, N.; Underhill, A. E.; Perepichka, I. F. J. Mater.
Chem. 1998, 8, 1541. (f) Ono, G.; Izuoka, A.; Sugawara, T.;
Sugawara, Y. J. Mater. Chem. 1998, 8, 1703. (g) Llacay, J.;
Mata, I.; Molins, E.; Veciana, J.; Rovira, C. Adv. Mater. 1998,
8. The acidity constant for TTF has been determined to be inter-
mediate between that of Et2OH1 and H3O1. See: Giffard, M.;
Alonso, P.; Garin, J.; Gorgues, A.; Nguyen, T. P.; Richomme,
P.; Robert, A.; Roncali, J.; Uriel, S. Adv. Mater. 1996, 6, 298.
9. (a) For related TTF annelated crown ethers, see: (a) Otsubo,
T.; Ogura, F. Bull. Chem. Soc. Jpn. 1985, 58, 1343.
(b) Hansen, T. K.; Jùrgensen, T.; Becher, J. J. Chem. Soc.,
Chem. Commun. 1992, 1550. (c) Hansen, T. K.; Jùrgensen, T.;
Stein, P. C.; Becher, J. J. Org. Chem. 1992, 57, 6403.
(d) Jùrgensen, T.; Girmay, B.; Hansen, T. K.; Becher, J.;
Underhill, A.; Hursthouse, M. B.; Harman, M. E.; Kilburn,
J. D. J. Chem. Soc., Perkin Trans. 1 1992, 2907.
 Â
10, 330. (h) Heuze, K.; Fourmigue, M.; Batail, P.; Canadell, E.;
Auban-Senzier, P. Chem. Eur. J. 1999, 5, 2971.
4. Ashton, P. R.; Campbell, P. J.; Chrystal, E. J. T.; Glink, P. T.;
Menzer, S.; Philp, D.; Spencer, N.; Stoddart, J. F.; Tasker,
P. A.; Williams, D. J. Angew. Chem., Int. Ed. Engl. 1995,
34, 1865.
È
10. Kramer, R.; Lehn, J.-M.; Marquis-Rigault, A. Proc. Natl.
Acad. Sci. USA 1993, 34, 1865.
11. Crystals of 13 were grown from a mixture of 1´PF6 and 13 in
CH2Cl2/MeCN layered with mixed hexanes. Crystals of 3
were grown from of a mixture of 1´PF6 and 3 in CH2Cl2/
5. (a) Ashton, P. R.; Chrystal, E. J. T.; Glink, P. T.; Menzer, S.;
Schiavo, C.; Stoddart, J. F.; Tasker, P. A.; Williams, D. J.
Angew. Chem., Int. Ed. Engl. 1995, 34, 1869. (b) Ashton,
P. R.; Chrystal, E. J. T.; Glink, P. T.; Menzer, S.;
Schiavo, C.; Spencer, N.; Stoddart, J. F.; Tasker, P. A.;
White, A. J. P.; Williams, D. J. Chem. Eur. J. 1996, 2, 709.
i
MeCN layered with Pr2O. Crystal data for 3: C42H56O12S8,
Mˆ1009.4, monoclinic, C2/c (no. 15), aˆ32.635(7), bˆ
Ê
Ê 3
4.975(2), cˆ32.408(6) A, bˆ116.01(1)8, Vˆ4728(3) A ,
Zˆ4 (the complex has crystallographic Ci symmetry),
Dcˆ1.418 g cm23
,
m(Cu-Ka)ˆ40.0 cm21
,
F(000)ˆ2128,
Â
Â
(c) Ashton, P. R.; Glink, P. T.; Martõnez-Dõaz, M.-V.;
Stoddart, J. F.; White, A. J. P.; Williams, D. J. Angew.
Chem., Int. Ed. Engl. 1996, 35, 1930. (d) Ashton, P. R.;
Glink, P. T.; Stoddart, J. F.; Tasker, P. A.; White, A. J. P.;
Williams, D. J. Chem. Eur. J. 1996, 2, 729. (e) Fyfe, M. C. T.;
Glink, P. T.; Menzer, S.; Stoddart, J. F.; White, A. J. P.;
Williams, D. J. Angew. Chem., Int. Ed. Engl. 1997, 36,
2068. (f) Ashton, P. R.; Fyfe, M. C. T.; Glink, P. T.;
Menzer, S.; Stoddart, J. F.; White, A. J. P.; Williams, D. J.
J. Am. Chem. Soc. 1997, 119, 12514. (g) Ashton, P. R.;
Collins, A. N.; Fyfe, M. C. T.; Glink, P. T.; Menzer, S.;
Stoddart, J. F.; Williams, D. J. Angew. Chem., Int. Ed. Engl.
Tˆ293 K; orange needles, 0.70£0.05£0.03 mm, re®ned
based on F2 to give R1ˆ0.091, wR2ˆ0.167 for 1455 indepen-
dent observed absorption corrected re¯ections [uFou.4s(uFou),
2u<1208] and 280 parameters. CCDC 148827. Crystal data
for 13: C21H28O6S5, Mˆ536.7, monoclinic, P21/n (no. 14),
Ê
aˆ19.633(1), bˆ5.026(1), cˆ25.918(2) A, bˆ104.66(1)8,
Vˆ2474.0(2) A , Zˆ4, Dcˆ1.441 g cm23
,
m(Cu-Ka)ˆ
Ê 3
46.2 cm21
,
F(000)ˆ1128, Tˆ293 K; yellow needles,
0.77£0.23£0.08 mm, re®ned based on F2 to give R1ˆ0.036,
wR2ˆ0.089 for 3418 independent observed absorption
corrected re¯ections [uFou.4s(uFou), 2u<1268] and 290
parameters. CCDC 148826.
Ê
12. Compare with the separation of 3.62 A observed for TTF. See:
Â
1997, 36, 59. (h) Feiters, M. C.; Fyfe, M. C. T.; Martõnez-
Â
Dõaz, M.-V.; Menzer, S.; Nolte, R. J. M.; Stoddart, J. F.; van
Kan, P. J. M.; Williams, D. J. J. Am. Chem. Soc. 1997, 119,
Phillips, T. E.; Kistenmacher, T. J.; Ferraris, J. P.; Cowan,
D. O. J. Chem. Soc., Chem. Commun. 1973, 471.
 Â
8119. (i) Ashton, P. R.; Fyfe, M. C. T.; Martõnez-Dõaz, M.-V.;