Trialkyltetrathiafulvalene-σ-tetracyanoanthraquinodimethane (R3TTF-σ-TCNAQ) diads: Synthesis, intramolecular charge-transfer properties, and X-ray crystal structure

Article abstract of DOI:10.1021/jo001576+

We report the use of the electron-donating 4,5-dipentyl-4′-methyl-TTF (TTF = tetrathiafulvalene) moiety in combination with the electron acceptor 11,11,12,12-tetracyanoanthraquinodimethane (TCNAQ) unit in the novel D-σ-A diad molecules 11, 17, and 18. These compounds display a weak, broad, low-energy intramolecular charge-transfer (ICT) band in the UV-vis spectra (λ_max 430-450 nm). Cyclic voltammetric studies show two reversible one-electron oxidation processes for the R₃TTF moiety, and a reversible two-electron reduction process for the TCNAQ moiety. The electron affinity of TCNAQ is significantly enhanced by the electron-withdrawing sulfonamide and sulfonic ester groups (compounds 17 and 18, respectively). Simultaneous electrochemistry and EPR (SEEPR) experiments show no significant intramolecular interaction between the R₃TTF and TCNAQ moieties in compounds 11 and 18. X-ray crystallographic data are presented for 5, 11, and 20. The structure of 5 reveals hydrogen-bonded dimers. In molecule 11 the bond lengths and conformations of both donor and acceptor moieties are typical for neutral species. Compound 20 is an unusual calcium complex of TCNAQ derivative obtained by dicyanomethylation of anthraquinone2-carboxylic acid.

Full text of DOI:10.1021/jo001576+

J . Org. Chem. 2001, 66, 4517-4524
4517
Tr ia lk yltetr a th ia fu lva len e-σ-Tetr a cya n oa n th r a qu in od im eth a n e
(R3TTF -σ-TCNAQ) Dia d s: Syn th esis, In tr a m olecu la r
Ch a r ge-Tr a n sfer P r op er ties, a n d X-r a y Cr ysta l Str u ctu r e
Dmitrii F. Perepichka,† Martin R. Bryce,*,† Andrei S. Batsanov,† J udith A. K. Howard,†
Alejandro O. Cuello,‡ Mark Gray,‡ and Vincent M. Rotello‡
Department of Chemistry, University of Durham, Durham DH1 3LE, U.K., and Department of Chemistry,
University of Massachusetts at Amherst, Amherst, Massachusetts 01003
m.r.bryce@durham.ac.uk
Received November 6, 2000
We report the use of the electron-donating 4,5-dipentyl-4′-methyl-TTF (TTF ) tetrathiafulvalene)
moiety in combination with the electron acceptor 11,11,12,12-tetracyanoanthraquinodimethane
(TCNAQ) unit in the novel D-σ-A diad molecules 11, 17, and 18. These compounds display a
weak, broad, low-energy intramolecular charge-transfer (ICT) band in the UV-vis spectra (λmax
430-450 nm). Cyclic voltammetric studies show two reversible one-electron oxidation processes
for the R3TTF moiety, and a reversible two-electron reduction process for the TCNAQ moiety. The
electron affinity of TCNAQ is significantly enhanced by the electron-withdrawing sulfonamide and
sulfonic ester groups (compounds 17 and 18, respectively). Simultaneous electrochemistry and EPR
(SEEPR) experiments show no significant intramolecular interaction between the R3TTF and
TCNAQ moieties in compounds 11 and 18. X-ray crystallographic data are presented for 5, 11,
and 20. The structure of 5 reveals hydrogen-bonded dimers. In molecule 11 the bond lengths and
conformations of both donor and acceptor moieties are typical for neutral species. Compound 20 is
an unusual calcium complex of TCNAQ derivative obtained by dicyanomethylation of anthraquinone-
2-carboxylic acid.
In tr od u ction
optics, synthetic light-harvesting systems, and theoretical
aspects of charge transport at the molecular level.6 The
covalent linkage of TTF and TCNQ (7,7,8,8-tetracyano-
quinodimethane) moieties has received special attention
since Aviram and Ratner’s theoretical proposal in 1974
that molecular rectification might be observed in as-
semblies of the hypothetical TTF-σ-TCNQ molecule 1
sandwiched between two metal electrodes M1 and M2 in
the architecture M1/D-σ-A/M2.7 Synthetic routes are
limited by the fact that a TTF nucleus appeared to be
incompatible with the standard Lehnert conditions (TiCl4,
malononitrile)8 for converting a quinone into a TCNQ
derivative, so preformed TTF-quinone diads2 are not
suitable as precursors. When a TCNQ component is used,
a major problem can be the irreversible formation of an
intermolecular TTF.TCNQ CT complex (which is usually
insoluble), instead of the desired covalent coupling reac-
tion.
The covalent linkage of tetrathiafulvalene (TTF) to a
π-acceptor moiety through a π- or σ-bonded bridge1 offers
considerable potential for the study of intramolecular
charge transfer (ICT) processes in D-A molecules. Sev-
eral acceptor groups, such as quinones,2 C60,3 and pyri-
dinium4 or bipyridinium cations5 have been studied
recently in this context. Systems of this general type are
central to studies on chromophores for dyes, nonlinear
† University of Durham.
‡ University of MassachusettssAmherst.
(1) Review: Bryce, M. R. Adv. Mater. 1999, 11, 11.
(2) (a) Watson, W. H.; Eduok, E. E.; Kashyap, R. P.; Krawiec, M.
Tetrahedron 1993, 49, 3035. (b) Frenzel, S.; Mu¨llen, K. Synth. Met.
1996, 80, 175. (c) Segura, J . L.; Mart´ın, N.; Seoane, C.; Hanack, M.
Tetrahedron Lett. 1996, 37, 2503. (d) Gonza´lez, M.; Illescas, B.; Martı´n,
N.; Segura, J . L.; Seoane, C.; Hanack, M. Tetrahedron 1998, 54, 2853.
(e) Moriarty, R. M.; Tao, A.; Gilardi, R.; Song, Z.; Tuladhar, S. M. Chem.
Commun. 1998, 157. (f) Scheib, S.; Cava, M. P.; Baldwin, J . W.;
Metzger, R. M. J . Org. Chem. 1998, 63, 1198. (g) Tsiperman, E.; Regev,
T.; Becker, J . Y.; Bernstein, J .; Ellern, A.; Khodorkovsky, V.; Shames,
A.; Shapiro, L. Chem. Commun. 1999, 1125. The statement in this
communication that “systems involving TTF-π-TCNQ are known”
is not supported by the references given. To our knowledge such
π-linked systems are unknown.
(3) (a) Prato, M.; Maggini, M.; Giacometti, C.; Scorrano, G.; Sandona,
G.; Farnia, G. Tetrahedron 1996, 52, 5221. (b) Mart´ın, N.; Sa´nchez,
L.; Seoane, C.; Andreu, R.; Garı´n, J .; Orduna, J . Tetrahedron Lett. 1996,
37, 5979. (c) Llacay, J .; Veciana, J .; Vidal-Gancedo, J .; Bourdelande,
J . L.; Gonza´lez-Moreno, R.; Rovira, C. J . Org. Chem. 1998, 121, 3951.
(d) Simonsen, K. B.; Konovalov, V. V.; Konovalova, T. A.; Kawai, T.;
Cava, M. P.; Kispert, L. D.; Metzger, R. M.; Becher, J . J . Chem. Soc.,
Perkin Trans. 2 1999, 657. (e) Mart´ın, N.; Sa´nchez, L.; Illescas, B.;
Pe´rez, I. Chem. Rev. 1998, 98, 2527.
Compound 2 was the first TTF-TCNQ diad to be
synthesized,9 but the difficult synthetic route and prob-
lems with purification precluded detailed characteriza-
tion, although EPR and IR data suggested an ionic
ground state. In contrast to this, compound 3 recently
proved to be straightforward to synthesize and to purify.10
(6) Reviews: (a) Paddon-Row: M. N. Acc. Chem. Res. 1994, 27, 18.
(b) Imahori, H.; Sasaka, Y. Adv. Mater. 1997, 9, 537. (c) Ashwell, G. J .
J . Mater. Chem. 1999, 9, 1991.
(7) Aviram, A.; Ratner, M. Chem. Phys. Lett. 1974, 29, 277. For
recent discussions of this proposal, see: Metzger, R. M. J . Mater. Chem.
1999, 9, 2027. Metzger, R. M. J . Mater. Chem. 2000, 10, 55.
(8) (a) Lehnert, W. Tetrahedron Lett. 1970, 4723. (b) Lehnert, W.
Synthesis 1974, 667.
(4) Goldenberg, L. M.; Becker, J . Y.; Levi, O. P-T.; Khodorkovsky,
V. Y.; Shapiro, L. M.; Bryce, M. R.; Cresswell, J . P.; Petty, M. C. J .
Mater. Chem. 1997, 7, 901.
(5) Simonsen, K. B.; Zong, K.; Rogers, R. D.; Cava, M. P.; Becher, J .
J . Org. Chem. 1997, 62, 679.
(9) Panetta, C. A.; Baghdadchi, J .; Metzger, R. M. Mol. Cryst. Liq.
Cryst. 1984, 107, 103.
10.1021/jo001576+ CCC: $20.00 © 2001 American Chemical Society
Published on Web 06/01/2001

4518 J . Org. Chem., Vol. 66, No. 13, 2001
Perepichka et al.
Ch a r t 1
Sch em e 1a
a
Reagents and conditions: (i) THF, LDA, -78 °C, 1.5 h, then CO2, -78 °C, 1.5 h; (ii) toluene/MeCN, oxalyl chloride, DMF, 20 °C, 2 h;
(iii) CH2Cl2, pyridine, then cyanuric fluoride, 20 °C, 1 h; (iv) CH2Cl2, PhCH2OH, pyridine, 20 °C, 1.5 h; (v) CH2Cl2, compound 9, Pyridine,
20 °C, 4 h; (vi) CH2Cl2, MeCOCl, Et3N, 20 °C, 2 h.
The TCNQ component in this molecule (TCNAQ: 11,-
11,12,12-tetracyanoanthraquinodimethane) is a weaker
acceptor than TCNQ [TCNAQ, E1/2 ) -0.285 V (a two-
Conversion to the carbonyl chloride 6 and carbonyl
fluoride 7 was readily achieved by reaction with oxalyl
chloride and with cyanuric fluoride-pyridine,13 respec-
tively. Reaction of 6 with TCNAQ derivative 911c afforded
the target molecule 11 as a brown crystalline solid in 50%
yield (Scheme 1).
1/2
1/2
electron wave) cf. TCNQ, E1 ) +0.130 and E2
)
-0.290 V, in MeCN vs SCE]; and in contrast to TCNQ
(which is essentially planar) TCNAQ adopts a “butterfly”
conformation (according to X-ray analysis and theoretical
calculations11) which will have the advantage of sup-
pressing intermolecular CT complex formation. Com-
pound 3 has an essentially neutral ground state, although
simultaneous electrochemistry and EPR (SEEPR) experi-
ments suggested intramolecular interaction of the TC-
NAQ fragment with TTF moiety in the radical cation
state. These initial studies on molecule 3 prompted us
to explore new TTF-σ-TCNAQ diads, and these results
are reported herein.
To enhance the acceptor properties of the TCNAQ
moiety, we prepared the sulfonamide and sulfonic ester
derivatives 15 and 16, respectively, starting from readily
available anthraquinone-2-sulfonyl chloride 12 (Scheme
2) and hence the molecules 17 and 18. The low yield,
observed for the acylation of compound 15 by 6 (13%) has
been overcome by the use of reagent 7 (74%) instead.
Attempts to prepare TCNAQ-2-carboxylic acid were
unsuccessful: reaction of anthraquinone-2-carboxylic acid
with Lehnert’s reagent under standard conditions8 re-
sulted in dicyanomethylation of the carboxy group (Scheme
3). The product was isolated as the calcium complex, the
possible source of calcium being the distillation of dichlo-
romethene (used in the synthesis) over CaH2, when some
inorganic materials were transferred into the receiving
flask. The presence of calcium in the product was
confirmed by atomic emission spectroscopy and crystals
of the interesting bis(TCNAQ) complex 20 were grown.
Its structure was proved by X-ray crystallographic analy-
sis (see below). Related dicyanomethylations of carboxylic
acid chlorides have been reported.14
Resu lts a n d Discu ssion
Syn th esis. Our targets were analogues of the proto-
type molecule 3 for which intramolecular charge-transfer
(ICT) could be enhanced by lowering the oxidation
potential of the TTF moiety and/or raising the electron
affinity of the TCNAQ moiety. We, therefore, considered
4,5-dipentyl-4′-methyl-TTF 4 to be an appropriate TTF
building block as alkyl substitution is known to lower
significantly the oxidation potential of TTF.12 Moreover,
the pentyl chains would enhance solubility in organic
solvents. Compound 4 was obtained by direct analogy
with the synthesis of trimethyl-TTF.12b Lithiation of 4
(LDA in THF at -78 °C) followed by reaction with carbon
dioxide gave the carboxylic acid derivative 5 in 61% yield.
Attempts to synthesize TCNAQ-2-carboxylic acid using
the tert-butyl and methyl esters of anthraquinone-2-
carboxylic acid were also unsuccessful: the tert-butyl
protected group was not stable toward Lehnert’s reagent,
whereas the methyl group in methyl TCNAQ-2-carboxy-
late could not be selectively removed, neither by acidic
hydrolysis (CF3COOH/H2O) nor by cyanide cleavage
(NaCN/HMPA).
(10) de Miguel, P.; Bryce, M. R.; Goldenberg, L. M.; Beeby, A.;
Khodorkovsky, V.; Shapiro, L.; Niemz, A.; Cuello, A. O.; Rotello, V. J .
Mater. Chem. 1998, 8, 71.
(11) (a) Aumu¨ller, A.; Hu¨nig, S. Liebigs Ann. Chem. 1984, 618. (b)
Kini, A. M.; Cowan, D. O.; Gerson, F.; Mo¨ckel, R. J . Am. Chem. Soc.
1985, 107, 556. (c) Torres, E.; Panetta, C. A.; Metzger, R. M. J . Org.
Chem. 1987, 52, 2944. (d) For a review of TCNQ acceptors see: Mart´ın,
N.; Segura, J . L.; Seoane, C. J . Mater. Chem. 1997, 7, 1661.
(12) (a) Ferraris, J . P.; Poehler, T. O.; Bloch, A. N.; Cowan, D. O.
Tetrahedron Lett. 1973, 2553. (b) Moore, A. J .; Bryce, M. R.; Batsanov,
A. S.; Cole, J . C.; Howard, J . A. K. Synthesis 1995, 675.
X-r a y Molecu la r Str u ctu r es of 5, 11, a n d 20.
Molecules 5 in the crystal are linked into centrosymmet-
(13) Cooke, G.; Rotello V. M.; Radhi A. Tetrahedron Lett. 1999, 40,
8611.
(14) Shi, S.; Wudl, F. J . Org. Chem. 1988, 53, 5379.

R3TTF-σ-TCNAQ Diads
J . Org. Chem., Vol. 66, No. 13, 2001 4519
Sch em e 2a
a
Reagents and conditions: (i) MeCN, N-methylethanolamine, 20 °C, 2 h, then 60 °C, 10 min; (ii) MeCN, hydroquinone, pyridine, 20
°C, 12 h; (iii) CH2Cl2, TiCl4, pyridine, â-alanine, reflux, 15 h; (iv) CH2Cl2, compound 6, pyridine, 20 °C, 4 h; (v) CH2Cl2, compound 7,
p-(dimethylamino)pyridine, 20 °C, 24 h.
Sch em e 3. Rea gen ts a n d con d ition s: (i) CH2Cl2
(d r ied over Ca H2), TiCl4, p yr id in e, â-a la n in e,
r eflu x, 15 h .
F igu r e 1. Molecular structure of 11.
moiety prevents the formation of segregated stacks. The
donor and acceptor fragments of 11 form an ADDA motif,
with no significant π-π interactions between them.
In complex 20 the Ca atom is located at an inversion
center and is coordinated octahedrally by two TCNAQ
anions (through their oxygen atoms), two acetonitrile and
two aqua ligands, with two more acetonitrile molecules
linked to the latter by hydrogen bonds. The tetracy-
anoanthraquinone moiety has the same conformation as
in 11 (æ ) 37°, θ ) 102°). The dicyanooxyetheno moiety
ric dimers by strong [O-H‚‚‚O 2.612(6) Å] hydrogen
bonds. As in 11 (see below), the carboxy group is
essentially coplanar with the TTF moiety, while the
n-pentyl substituents adopt a distinctly out-of-plane
conformation. The TTF moiety shows small boatlike
folding along the S‚‚‚S vectors (by 5° and 10°) and a 4°
twist around the central CdC bond.
In molecule 11 (Figure 1) the TTF moiety is folded
along the S(1)‚‚‚S(2) and S(3)‚‚‚S(4) vectors by 22° and
11° in a boat manner. The tetracyanoanthraquinone
moiety adopts a usual11 saddle-like conformation; the
anthraquinone moiety is folded along the C(9)‚‚‚C(10)
vector by an angle æ ) 37°, while the two C(CN)2 moieties
are tilted in the opposite direction and form a dihedral
angle θ ) 101°. Bond distances and conformations in both
the donor and the acceptor moieties are typical for
neutral species, as exemplified by 5, and TCNAQ.11a In
the crystal, the nonplanar conformation of the TCNAQ
is planar with strong π-delocalization, but is not conju-
gated with the benzene ring, with which it forms a
dihedral angle of 48°.
Electr och em ica l a n d Sp ectr oscop ic Stu d ies. The
electrochemical reduction/oxidation potentials of the new
diads and related compounds, obtained from cyclic vol-
tammetry experiments are presented in Table 1. TTF-
TCNAQ hybrids 3, 11, 17, and 18 show electrochemically
amphoteric behavior. A reversible two-electron reduction
wave yields the dianion, and two single-electron oxidation
waves, give, sequentially, the radical cation and dication
species (Figure 2).
J udging from the reduction/oxidation potentials, the
acceptor ability of TCNAQ fragment is unaffected by the
presence of the TTF moiety in the same molecule, and
only minor variation in the oxidation potential of the TTF
fragment with different acceptor moieties has been
observed. The chemical modifications to both the donor

4520 J . Org. Chem., Vol. 66, No. 13, 2001
Perepichka et al.
Ta ble 1. Oxid a tion a n d Red u ction P oten tia ls of th e TTF
a n d TCNAQ Der iva tives a n d Th eir Hybr id s, V vs SCE
compound
E1/2
E1/2
E1/2
red
1ox
2ox
3
4
0.44
0.24
0.36
-
0.79
0.64
0.76
-
-0.36
-
5a
9
-
-0.38
-0.36
-0.28
-0.25
-0.28
-0.24
11
15
16
17
18
0.36
-
0.71
-
-
0.37
0.38
-
0.75
0.76
a
Chemical stability of radical cation and dication species
derived from compound 5 is much lower than that for the other
TTF derivatives due to the presence of the carboxy group; a
reversible well-defined voltammogram was obtained only at a scan
rate of 5000 mV/s.
F igu r e 3. Electronic absorption spectra of compounds 11, 17,
18 in MeCN.
F igu r e 4. SEEPR spectra of (a) 8+•, at +0.47 V, g ) 2.006;
(b) 11+•, at +0.55 V, g ) 2.006.
F igu r e 2. Cyclic voltammetry of compounds 3 and 18 in
MeCN solution, scan rate 100 mV/s.
Ta ble 2. Exp er im en ta l Hyp er fin e Cou p lin g Con sta n ts
(h fc, in G) for 8+•, 11+•, a n d 18+• (r 2 for sp ectr a l cu r ve
fittin g >0.98)a
and the acceptor moieties (as compared with prototype
molecule 3) increased the electron affinity and lowered
the oxidation potential, respectively: incorporation of
three alkyl substituents on the TTF nucleus lowered its
oxidation potential by 60-80 mV, and replacement of the
oxymethyl substituent in TCNAQ by a sulfoxy substitu-
ent increased the reduction potential by 110-120 mV
(Table 1, Figure 2). A smaller effect (80 mV) is seen for
the dialkylsulfamido group, in agreement with the weaker
electron-withdrawing ability of this substituent.
A charge-transfer interaction between donor and ac-
ceptor moieties of compounds 3, 11, 17, and 18 is
manifested by the appearance of weak broad absorption
band in the 400-550 nm region of their electronic
spectra. This absorption is not observed in solutions
obtained by mixing the corresponding TTF and TCNAQ
derivatives, and its intensity shows a linear dependence
on concentration, as expected for an intramolecular
charge-transfer (ICT) band. The maximum of the ICT
band for these compounds varies only slightly with the
change of substituents and σ-linkage between the donor
and the acceptor (Figure 3). The lowest energy ICT band
(λmax ) 445 nm in MeCN, 456 nm in dichloromethane,
455 nm in benzene) belongs to compound 18, the TTF
and TCNAQ moieties of which possess the strongest
donor and acceptor abilities, respectively. No fluorescence
from the ICT band has been found.
hfc
11+•
number of
hydrogens
hydrogen
8+•
18+•
Ha
Hb
Hc
Hd
He
Hf
Hg
Hh
Hi
1
1
1
2
2
2
2
2
3
0.02
0.02
0.02
0.03
b
0.02
0.02
0.02
0.02
0.02
0.02
0.87
0.71
0.28
0.05
0.06
0.07
0.02
0.06
0.09
0.80
0.80
0.28
b
0.79
0.79
0.20
a
b
For 8, 11, and 18, g factor of radical cations is 2.006. These
hydrogens are not present in this molecular structure.
this similarity in hyperfine couplings between these
radical cations to a very small or insignificant electronic
communication between the TTF moiety and the rest of
the molecule.
It is noteworthy that a strong EPR signal was also
observed upon the reduction of compounds 8, 11, 16,
despite the two-electron nature of this process. As was
earlier suggested by Kini,16 we hypothesize that this
signal originates from the radical anion of the TCNAQ
moiety, which is in equilibrium with the dianion species:
TCNAQ + TCNAQ2- h 2 TCNAQ-•
Sim u ltan eou s Electr och em istr y an d EP R (SEEP R)
Stu d ies. SEEPR spectra of 8+• and 11+• (Figure 4), and
18+• are quite similar. Curve fitting of the experimental
spectra to extract the hyperfine coupling constants (Table
2) provided results that were similar for all three
compounds within the experimental error.15 We attribute
(15) This could also be influenced by the fact that EPR spectra are
poorly resolved. However, this limitation is inherent to the compounds
involved. Attempts to obtain better resolved spectra by changing
instrumental variables and experimental conditions were unsuccessful.

R3TTF-σ-TCNAQ Diads
J . Org. Chem., Vol. 66, No. 13, 2001 4521
SEEP R exp er im en ts were carried out in a flat quartz cell.
The Pt gauze was inserted into the flat portion of the cell. The
Ag wire pseudoreference electrode was positioned directly
above the working electrode to reduce the iR-drop and the
auxiliary electrode, a Pt wire spiral of large surface area,
occupied the solvent reservoir above the flat section. EPR
spectra were recorded on an IBM ESP-300 X-band spectrom-
eter equipped with a TE104 single cavity. Solutions of the
-
investigated compounds (10-3 M in CH2Cl2, 0.1 M Bu4N+ClO4
)
were degassed by bubbling argon through them for 5 min and
then injected into the SEEPR cell, which was previously
flushed with argon. Bulk electrolysis was then carried out
simultaneously with signal acquisition (100 kHz field modula-
tion, modulation amplitude 0.4 G, 60 G sweep width). Experi-
mental hyperfine coupling constants were obtained through
spectral simulation and iterative curve fitting.19 The g factors
given are within the error of 0.25%.
X-r a y Cr ysta llogr a p h y. X-ray diffraction experiments
were carried out on a SMART 3-circle diffractometer with a
1K CCD area detector, using graphite-monochromated Mo-
KR radiation (λh ) 0.71073 Å) and a Cryostream (Oxford
Cryosystems) open-flow N2 gas cryostat. A combination of 4
sets of ω scans; each set at different æ and/or 2θ angles,
nominally covered over a hemisphere of reciprocal space (for,
20 full sphere was covered by five sets). Reflection intensities
were integrated using SAINT program (Version 6.01, Bruker
Analytical X-ray Systems, Madison, WI, 1999) and corrected
for absorption by numerical method based on crystal face
indexing (5, 11) or by semiempirical method based on the
intensities of Laue equivalents (20), using SADABS software
(G. M. Sheldrick, University of Go¨ttingen, 1998). The struc-
tures were solved by direct methods and refined by full-matrix
least squares against F2 of all data, using SHELXTL software
(Version 5.1, Bruker AXS, Madison, WI, 1998). Full structural
information has been deposited with the Cambridge Crystal-
lographic Data Centre.20
F igu r e 5. SEEPR spectra of (a) 10-•, at -0.87 V, g ) 2.006;
(b) 11-•, at -0.50 V, g ) 2.005.
SEEPR spectra of 10-• and 11-• (Figure 5), and 16-•
and 18-• 17
where compounds 10 and 16 lack the TTF
,
substructure, are essentially identical, showing a broad,
unresolved singlet.18 Once again, the analysis of these
spectra shows no significant electronic interaction be-
tween the TTF moiety and the acceptor part of the
molecule.
Con clu sion s
Novel D-σ-A diads 11, 18, and 19, where D and A
are TTF and TCNAQ nuclei, respectively, substituted
with electron-releasing and electron-withdrawing sub-
stituents have been synthesized. ICT in these diads is
manifested in a weak broad absorption band in the 400-
550 nm region of their electronic spectra. In CV experi-
ments they show a clear amphoteric behavior consisting
of two single-electron oxidation waves and one two-
electron reduction wave. The position of these waves is
almost unaffected by the counterpart D (A) moiety. The
incorporation of electron-releasing and electron-with-
drawing substituents in D and A fragments, respectively,
enhances the redox properties of these fragments and
decrease the HOMO-LUMO gap of the molecule. The
first crystal structure of a TTF-TCNQ hybrid 11 has
been reported. It shows that D and A fragments of the
molecule are essentially neutral, and also there are no
significant π-π interactions between donor and acceptor
moieties in the solid state. Future work will be directed
at enhancing the ICT properties of TTF-TCNQ hybrids
by chemical modification of D and A moieties.
4-Meth yl-4′,5′-d ip en tyltetr a th ia fu lva len e 4. Trimethyl
phosphite (3.3 mL, 28 mmol) was added dropwise to 4-methyl-
1,3-dithiolium iodide21 (6.2 g, 25.5 mmol) suspended in dry
MeCN (150 mL) at 0-5 °C, and the reaction mixture was
stirred for 40 min at 20 °C, resulting in full dissolution of the
dithiolium salt. The solvent was then removed in vacuo, the
residue was dissolved in dry THF (120 mL), and potassium
tert-butoxide (2.99 g, 26.7 mmol) was added at -78 °C. The
reaction mixture was stirred at -78 °C for 1 h, and then
N-(4,5-dipentyl-1,3-dithiol-2-ylidene)piperidinium hexafluoro-
phosphate22 (8.9 g, 20 mmol) was gradually added. The
reaction mixture was allowed to reach 20 °C overnight, it was
diluted with ether (100 mL), stirred for 1 h, and filtered
through Celite, affording a clear dark-brown solution, which
was reduced to ca. 15 mL, and toluene (100 mL) and acetic
acid (10 mL) were added. The solution was stirred for 1.5 h,
washed with ice-cold water, and dried over MgSO4, and the
solvent was removed in vacuo. The resulting brown oil was
chromatographed on silica gel, eluting with ethyl acetate/
petroleum ether (1:3 v/v), giving pure 4 (5.95 g, 65%) as an
Exp er im en ta l Section
Gen er a l m eth od s are the same as those described previ-
ously.10
1
orange oil. H NMR (300 MHz, acetone-d6) δ 6.17 (1H, q, J )
1.5 Hz), 2.42 (4H, t, J ) 7.5 Hz), 2.07 (3H, d, J ) 1.5 Hz), 1.52
(4H, m), 1.26-1.40 (8H, m), 0.90 (6H, t, J ) 6.9 Hz); 13C NMR
(75 MHz, acetone-d6) δ 132.3, 129.7, 129.6, 114.4, 110.2, 108.3,
31.9 (2C), 30.17, 30.16, 29.18, 29.16, 23.1 (2C), 16.2, 14.3 (2C);
IR (neat) ν/cm-1 1463, 1110, 779; MS (EI) m/z 358 (M+, 100%).
Anal. Calcd for C17H26S4: C, 56.93, H, 7.31. Found: C, 57.31,
H, 7.44.
Cyclic volta m m etr y experiments were performed using
Ag/AgNO3 (in MeCN) reference electrodes; the potentials were
corrected using ferrocene/ferrocenium (Fc/Fc+) couple (which
was used as internal standard except when it overlapped with
the oxidation peaks of the sample) and then recalculated to
the SCE scale. The Fc/Fc+ couple showed 0.37 V (vs SCE), 0.07
V (vs Ag/AgNO3) and 0.45 V (vs Ag/AgCl). 0.1 M Tetrabutyl-
ammonium hexafluorophosphate in MeCN was used as the
electrolyte.
(19) NIEHS WinSym EPR, version 0.95, D. Duling, 1994, Laboratory
of Molecular Biophysics, NIEHS, NIH, DHHS.
(20) Supplementary publication number CCDC-142177 (5), -142176
(11), and -142178 (20) can be obtained on request from the Director,
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge,
CB12 1E2, U.K.
(21) Bryce, M. R.; Finn, T.; Moore, A. J .; Batsanov, A. S.; Howard,
J . A. K. Eur. J . Org. Chem. 2000, 51.
(22) This was prepared by analogy with 4,5-dimethyl-1,3-dithiol-2-
ylidene piperidinium hexafluorophosphate from 7-chloro-6-dode-
canone: Mora, H.; Fabre, J .-M.; Giral, L.; Montginoul, C. Bull. Soc.
Chim. Belg. 1992, 101, 137.
(16) Kini, A. M.; Cowan, D. O.; Gerson, F.; Mockel, R. J . Am. Chem.
Soc. 1985, 107, 556
(17) The SEEPR spectrum of 18-. changes over time, due to
decomposition of the radical anion into unidentified species. Its
conversion over time is shown in the supplementary data, along with
SEEPR of compound 16.
(18) Spectral curve fitting was not performed on 10-•, 11-•, or 16-•
SEEPRs, since no meaningful values will be obtained due to the low
resolution of the spectra and the large number of variables to adjust.

4522 J . Org. Chem., Vol. 66, No. 13, 2001
Perepichka et al.
4-Ca r boxy-5-m eth yl-4′,5′-d ip en tyltetr a th ia fu lva len e 5.
To a solution of 4 (0.67 g, 1.86 mmol) in anhydrous ether (80
mL) was added LDA (1.5 M in hexane; 1.8 mL, 2.7 mmol) at
-78 °C, and the solution was stirred at this temperature for
1.5 h (a light-yellow precipitate formed after 0.5 h) and a strong
flow of dry CO2 was bubbled through the reaction mixture for
1.5 h. The reaction mixture was allowed to warm to 20 °C
overnight, it was diluted with aqueous HCl (0.5 M; 30 mL),
and the organic layer was separated, washed with water and
brine, and dried over MgSO4. The solution volume was reduced
to 5 mL and hot hexane (20 mL) was added, and then the
solvent was distilled, until red needles of the product started
to precipitate from the hot solution. After cooling, the red
crystalline precipitate was filtered off and washed with hexane,
was stirred for 4 h at 20 °C. The solvent was removed, and
the residue was chromatographed on silica gel, eluting with
ethyl acetate/hexane (2:3 v/v). The first red fraction on
evaporation gave a red oily solid, which was assumed to be
anhydride of acid 5 (18 mg). 1H NMR (300 MHz, acetone-d6) δ
2.49 (3H, s), 2.45 (4H, t, J ) 7.5 Hz), 1.47-1.60 (4H, m), 1.29-
1.40 (8H, m), 0.90 (6H, t, J ) 6.9 Hz); IR (KBr) ν/cm-1 1773
(CdO), 1684 (CdO).
Evaporation of the second yellow-brown fraction gave
product 11 (68 mg, 61%). It was stirred in 2-propanol (3 mL)
at 35 °C and then cooled to 20 °C, and the brown crystalline
product was filtered off and washed with 2-propanol, resulting
1
in pure 11 (56 mg, 50%), mp 200 °C (from acetone). H NMR
(300 MHz, acetone-d6) δ 8.42-8.32 (4H, m), 7.97-7.85 (3H,
1
yielding 5 (0.45 g, 61%), mp 132-133 °C. H NMR (300 MHz,
m), 5.49 (2H, s), 2.43 (4H, t, J ) 7.5 Hz), 2.42 (3H, s), 1.58-
1.46 (4H, m), 1.39-1.27 (8H, m), 0.89 (6H, t, J ) 6.9 Hz); 13
C
acetone-d6) δ 2.46 (4H, t, J ) 7.2 Hz), 2.40 (3H, s), 1.58-1.48
(4H, m), 1.37-1.30 (8H, m), 0.90 (6H, t, J ) 6.9 Hz); 13C NMR
(75 MHz, acetone-d6) δ 161.2, 147.5, 129.9, 129.6, 121.4, 111.1,
104.2, 31.9 (2C), 30.18, 30.17, 29.17, 29.15, 23.0 (2C), 16.0, 14.3
(2C); IR (KBr) ν/cm-1 3400-3600 (OH), 1678 (CdO), 1652
(CdO), 1574, 1298, 1276; MS (EI) m/z 402 (M+, 16%), 358
[(M - CO2)+, 33%], 83 (100%). Anal. Calcd for C18H26O2S4: C,
53.72, H, 6.52. Found C, 53.40, H, 6.48.
NMR (75 MHz, acetone-d6) δ 161.02, 160.98, 160.2, 149.6,
141.6, 133.1 (2C), 132.1, 132.0, 131.6 (2C), 131.3, 130.0, 129.7,
128.8, 128.51, 128.49, 127.2, 119.8, 114.6 (2C), 114.5 (2C),
111.9, 103.8, 84.7, 84.4, 66.3, 31.9 (2C), 30.18 (2C), 29.15 (2C),
23.0 (2C), 16.3, 14.2 (2C); IR (KBr) ν/cm-1 2227 (CtN), 1712
(CdO), 1560, 1229; λ/nm (ꢀ/M-1 cm-1) 283 (40500), 304 (28100),
317 (27600), 430 (2100); MS (EI) m/z 718 (M+, 21%), 358
(100%). Anal. Calcd for C39H34N4O2S4: C, 65.15; H, 4.77; N,
7.79. Found: C, 64.92; H, 4.70; N, 7.70.
4-(Ch lor oca r bon yl)-5-m eth yl-4′,5′-d ip en tyltetr a th ia fu l-
va len e 6. To a solution of acid 5 (86 mg, 0.213 mmol) in
toluene/acetonitrile (5:1 v/v; 10 mL) were added oxalyl chloride
(0.021 mL, 0.24 mmol) and DMF (1 drop of a 10% solution in
toluene), and the solution was stirred at 20 °C for 2 h. The
reaction mixture was filtered through a pad of dry silica gel
(1 cm) and dry neutral alumina, the filter was washed with
toluene, and the filtrate was evaporated in vacuo yielding 6
(80 mg, 89%) as a dark-red oil, which was used without further
purification.
N-Meth yl-N-(9,12-a n th r a qu in on e-2-su lfon yl)eth a n ola -
m id e 13. To a suspension of sulfonyl chloride 12 (1.76 g, 5.74
mmol) in dry MeCN (30 mL) was added N-methylethanola-
mine (1.05 mL, 13.1 mmol), resulting in an exothermic reaction
and dissolution of the sulfonyl chloride. The reaction mixture
was stirred for 2 h at 20 °C, heated to 60 °C to dissolve the
precipitate of the product, and cooled to 0 °C. The precipitate
was filtered off and washed with cold MeCN and hot water,
yielding pure 13 (1.64 g, 83%), mp 149-151 °C; 1H NMR (200
MHz, DMSO-d6) δ 8.41 (1H, d, J ) 1.2 Hz), 8.38 (1H, d, J )
8.5 Hz), 8.18-8.30 (3H, m) 7.91-8.01 (2H, m), 4.82 (1H, t, J
) 5.6 Hz), 3.52 (2H, q, J ) 5.6 Hz), 3.12 (2H, t, J ) 5.6 Hz),
2.81 (3H, s); 13C NMR (75 MHz, DMSO-d6) δ 181.6, 181.4,
142.3, 135.4, 134.78, 134.76, 133.6, 132.9 (2C), 131.9, 128.2,
126.84, 126.80, 124.8, 58.8, 51.8, 53.4; IR (KBr) ν/cm-1 1675
(CdO), 1589, 1326 (SdO), 1150 (SdO); MS (CI) m/z 363
(MNH4+, 49%), 346 (MH+, 100%), 314 (M+ - CH2OH, 12%).
Anal. Calcd for C17H15NO5S: C, 59.12; H, 4.38; N, 4.06.
Found: C, 58.89; H, 4.20; N, 3.99.
4-(Flu or oca r bon yl)-5-m eth yl-4′,5′-d ip en tyltetr a th ia fu l-
va len e 7. To a solution of acid 5 (101 mg, 0.25 mmol) and
pyridine (0.04 mL, 0.25 mmol) in dry dichloromethane (3 mL)
was added cyanuric fluoride (0.04 mL, 0.25 mmol) at 0 °C, and
the dark-red solution was stirred at 20 °C for 1 h. Then the
organic layer was washed thoroughly with water and brine
and dried over MgSO4, and the product was purified by flash
chromatography on silica gel (eluent: dichloromethane) yield-
ing 7 (63 mg, 62%) as a dark-red oil. 1H NMR (300 MHz,
CDCl3) δ 2.41 (3H, d, J ) 0.9 Hz), 2.35 (4H, d, J ) 7.5 Hz),
1.56-1.44 (4H, m), 1.38-1.24 (8H, m), 0.90 (6H, t, J ) 6.9
Hz); 13C NMR (75 MHz, CDCl3) δ 157.2 (d, 3J CF ) 6 Hz), 149.9
(d, 1J CF ) 332 Hz), 129.4, 128.8, 115.5, 114.8 (d, 2J CF ) 70 Hz),
101.2, 31.48, 31.47, 29.67, 29.65, 29.00, 28.97, 22.6 (2C), 16.9
4-(9,12-An th r a qu in on e-2-su lfoxy)p h en ol 14. To a solu-
tion of hydroquinone (500 mg, 4.54 mmol) and pyridine (0.08
mL, 1.0 mmol) in dry MeCN (10 mL) was added dropwise a
solution of sulfonyl chloride 1224 (300 mg, 0.907 mmol) in dry
dichloromethane (10 mL). The reaction mixture was stirred
overnight at 20 °C, the solvent was removed in vacuo, and the
residue solid was stirred with 60% aqueous methanol (10 mL),
filtered off, and washed with methanol, yielding crude ester
14 (310 mg). It was dissolved in refluxing acetic acid (8 mL),
cooled, and filtered from the minor precipitate which formed
immediately on cooling and left to crystallize overnight to give
4
(d, J CF ) 3 Hz), 14.2 (2C); 19F NMR (188 MHz, CDCl3) δ 34.6
(COF); IR (KBr) ν/cm-1 1793 (CdO), 1217; MS (EI) m/z 404
(M+, 100%). Anal. Calcd for C18H25FOS4: C, 53.43, H, 6.23.
Found C, 53.54, H, 6.27.
4-(Ben zyloxyca r bon yl)-5-m eth yl-4′,5′-d ip en tyltetr a th i-
a fu lva len e 8. To a cold (0 °C) solution of carbonyl fluoride 7
(36 mg, 0.089 mmol) and p-(dimethylamino)pyridine (19 mg;
0.156 mmol) in dry dichloromethane was added benzyl alcohol
(200 µL, 0.194 mmol), and the reaction mixture was stirred
at 20 °C for 1.5 h. The solvent was removed, and the residue
was chromatographed on silica gel [eluent: ethyl acetate/
petroleum ether (1:4 v/v)] giving compound 8 (42 mg, 96%) as
an oily solid. 1H NMR (300 MHz, acetone-d6) δ 7.47-7.32 (5H,
m), 5.26 (2H, s), 2.42 (3H, t, J ) 7.2 Hz), 2.41 (3H, s), 1.57-
1
pure 14 (235 mg, 64%), mp 230-232 °C; H NMR (300 MHz,
DMSO-d6) δ 9.77 (1H, s), 8.45-8.39 (2H, m), 8.34-8.20 (3H,
m) 8.03-7.96 (2H, m), 6.86 (2H, d, J ) 9 Hz), 6.69 (2H, d, J )
9 Hz); 13C NMR (100 MHz, acetone-d6) δ 182.3, 181.8, 157.2,
142.7, 140.9, 137.7, 135.6 (2C), 134.9, 134.1, 134.0, 133.8,
129.1, 127.85, 127.83, 127.5, 124.0 (2C), 116.7 (2C); IR (KBr)
ν/cm-1 1673 (CdO), 1590, 1503, 1353 (SdO), 1293, 1195
(SdO), 869 (S-O), 849 (S-O); MS (EI) m/z 380 (M+, 33%), 208
(100%). Anal. Calcd for C20H12O6S: C, 63.15; H, 3.18. Found:
C, 62.66; H, 3.24.
1.46 (4H, m), 1.38-1.26 (8H, m), 0.89 (6H, t, J ) 6.6 Hz); 13
C
NMR (75 MHz, acetone-d6) δ 159.7, 148.0, 136.1, 129.3, 129.0,
128.8 (2C), 128.5, 128.4 (2C), 119.6, 111.0, 103.2, 67.0, 31.2
(2C), 29.54, 29.51, 28.53, 28.50, 22.4 (2C), 15.5, 13.6 (2C); IR
(KBr) ν/cm-1 1705 (CdO), 1249; MS (EI) m/z 492 (M+, 28%),
129 (100%). Anal. Calcd for C25H32O2S4: C, 60.94, H, 6.55.
Found C, 61.04, H, 6.56.
2-[(2-Hyd r oxyeth yl)m eth yla m id osu lfon yl)-13,13,14,14-
tetr a cya n oa n th r a qu in od im eth a n e 15. This was synthe-
sized using anthraquinone 13 (1.43 g, 4.14 mmol), malononi-
trile (4.04 g, 61.8 mmol), pyridine (4.05 mL, 50 mmol), and
titanium tetrachloride (1 M solution in dichloromethane, 21
mL, 21 mmol) and â-alanine25 (1.6 g, 18 mmol) as described
2-Acetoxym eth yl-13,13,14,14-tetr a cya n oa n th r a qu in o-
d im eth a n e 10 was prepared as described before.10
2-(4-Meth yl-4′,5′-d ip en tyltetr a th ia fu lva len yl-5-ca r bon -
yloxym eth yl)-13,13,14,14-tetr a cya n oa n th r a qu in od im eth -
a n e 11. To a solution of TCNAQ-CH2OH23 9 (51.8 mg, 0.155
mmol) and pyridine (24 mg, 0.30 mmol) in dry dichloromethane
was added compound 6 (0.17 mmol), and the reaction mixture
(23) Torres, E.; Panetta C. A. J . Org. Chem. 1987, 52, 2944.
(24) Armitage, B.; Changjun Yu; Devadoss, C.; Schuster, G. B. J .
Am. Chem. Soc. 1994, 116, 9847.

R3TTF-σ-TCNAQ Diads
J . Org. Chem., Vol. 66, No. 13, 2001 4523
for 9. After removal of dichloromethane, the residue was
vigorously stirred with a mixture of ethyl acetate (100 mL)
and 5% aqueous HCl (100 mL), and the precipitate was filtered
off, washed with the same solvent mixture, with water and
MeOH, yielding crude 15 (1.28 g, 69%). The mother liquor was
combined with washing ethyl acetate, the organic layer was
separated, washed with water, and dried over MgSO4, and its
volume was reduced to 30 mL, resulting in precipitation of an
additional portion of 15 (0.16 g, 10%). Both portions were
recrystallized from MeCN (50 mL; filtering from insoluble
impurities while hot), yielding pure 15 (1.37 g, 74%), mp >
300 °C (dec). 1H NMR (200 MHz, DMSO-d6) δ 8.59 (1H, d, J )
1.4 Hz), 8.46 (1H, d, J ) 8.2 Hz), 8.35-8.18 (3H, m) 7.98-
7.83 (2H, m), 4.86 (1H, d, J ) 5.4 Hz), 3.54 (2H, d, J ) 5.4
Hz), 3.15 (2H, t, J ) 5.6 Hz), 2.88 (3H, s); 13C NMR (50 MHz,
acetone-d6) δ 158.5 (2C), 140.3, 133.7, 132.5 (2C), 131.3, 130.1,
129.9, 129.8, 128.5, 127.6, 127.5, 125.6, 113.8 (4C, br), 84.5
(2C, br), 59.1, 52.1, 35.6; IR (KBr) ν/cm-1 2231 MS (CI) m/z
459 (MNH4+, 100%), 442 (MH+, 18%), 410 (M+ - CH2OH,
17%). Anal. Calcd for C23H15N5SO3: C, 62.57, H, 3.43, N, 15.87.
Found: C, 62.60; H, 3.34; N, 15.66.
2-(4-H yd r oxyp h en yloxysu lfon yl)-13,13,14,14-t et r a cy-
a n oa n th r a qu in od im eth a n e 16. Anthraquinone 14 (190 mg,
0.500 mmol), â-alanine (200 mg, 2.25 mmol), and malononitrile
(500 mg, 7.58 mmol) were suspended in dry dichloromethane
(12 mL) and titanium tetrachloride (1 M in dichloromethane;
2.5 mL, 2.5 mmol) was added dropwise, keeping the temper-
ature at 0 °C. Then pyridine (0.46 mL, 6.0 mmol) was added,
and the reaction mixture was refluxed for 15 h. After removing
the solvent, the residue was dissolved in a mixture of ethyl
acetate (30 mL) and 5% aqueous HCl (20 mL), and the organic
layer was washed with 5% HCl and then brine and dried over
MgSO4. The solvent was removed, and the residue was
chromatographed on silica gel, eluting initially with dichlo-
romethane (to remove an excess of malononitrile) and then
with dichloromethane/ethyl acetate (5:1 v/v) to elute a product
which was dissolved in hot methanol (5 mL). Evaporation of
methanol (1-2 mL) in vacuo resulted in the precipitation of a
yellow solid which could not be redissolved in methanol, even
at reflux. It was filtered off, washed with MeOH, yielding pure
16 (165 mg, 69%) as a yellow solid, mp 260 °C (dec) (phase
transition at ca. 150 °C). 1H NMR (300 MHz, acetone-d6) δ
8.85 (1H, dd, J ) 1.8 and 0.3 Hz), 8.67 (1H, s), 8.56 (1H, dt, J
) 8.1 and 0.3 Hz), 8.41-8.35 (2H, m), 8.24 (1H, dd, J ) 8.1
and 1.8 Hz), 7.98-7.92 (2H, m), 6.94 (2H, d, J ) 9 Hz), 6.76
(2H, d, J ) 9 Hz); 13C NMR (75 MHz, acetone-d6) δ 159.0,
158.9, 156.9, 142.1, 138.4, 136.1, 132.9, 132.8, 132.4, 131.7,
130.6, 130.5, 128.9, 128.1, 128.0, 127.2, 123.3 (2C), 116.4 (2C),
113.7, 113.5 (2C), 113.4, 85.8, 85.4; IR (KBr) ν/cm-1 2231
(CtN), 1503, 1380 (SdO), 1198 (SdO), 869 (S-O), 848 (S-
O); (MS (EI) m/z 476 (M+, 29%), 304 (100%). Anal. Calcd for
The solvent was removed, and the residue was chromato-
graphed on silica gel [eluent: ethyl acetate/petroleum ether
(1:3 v/v)]. The fraction containing product was collected and
evaporated in vacuo, and the residue (102 mg) was stirred in
methanol, filtered off, and washed with methanol, giving
compound 17 (93 mg, 74%), mp 196-198 °C. 1H NMR (200
MHz, acetone-d6) δ 8.73 (1H, d, J ) 1.6 Hz), 8.56 (1H, d, J )
8.2 Hz), 8.44-8.26 (3H, m), 7.99-7.88 (2H, m), 4.42 (2H, t, J
) 5.0 Hz), 3.60 (2H, t, J ) 5.0 Hz), 3.03 (3H, s), 2.44 (2H, t, J
) 6.0 Hz), 2.40 (2H, t, J ) 6.0 Hz), 2.35 (3H, s), 1.60-1.42
(4H, m), 1.41-1.25 (8H, m), 0.90 (6H, t, J ) 6.3 Hz); 13C NMR
(75 MHz, CDCl3) δ 158.7, 158.4, 142.5, 133.4, 133.0, 132.9,
131.3, 130.5, 129.8, 129.6, 128.5, 127.9, 127.8, 126.0, 112.78,
112.61, 112.55, 112.45, 84.7, 84.6, 62.8, 49.0, 36.2, 31.2 (2C),
29 (4C, br), 22.4 (2C), 16 (br), 13.98, 13.97; λ/nm (ꢀ/M-1 cm-1
)
283 (40200), 307 (30000), 327 (30800), 425sh (1900); IR (KBr)
ν/cm-1 2229 (CtN), 1717 (CdO), 1560, 1458, 1340 (SdO), 1156
(SdO), 1236; MS (EI) m/z 825 (M+, 100%). Anal. Calcd for
C
41H39N5O4S5: C, 59.61, H, 4.76, N, 8.48. Found: C, 59.95, H,
4.77, N, 8.48.
1-(4-Meth yl-4′,5′-d ip en tyltetr a th ia fu lva len yl-5-ca r bon -
yloxy)-4-(13,13,14,14-tetr acyan oan th r aqu in odim eth an e-2-
su lfon yloxy)ben zen e 18. This was obtained using 16 (65 mg,
0.137 mmol) and carbonyl chloride 6 [from acid 5 (67 mg, 0.166
mmol)] as described for 11. After chromatography crude 18
(45 mg, 38%) was stirred in warm methanol (2 mL) and cooled,
and the precipitate was filtered, yielding pure 18 (28 mg, 24%)
as a brown solid, mp 120-125 °C. 1H NMR (300 MHz, acetone-
d6) δ 8.86 (1H, d, J ) 1.2 Hz), 8.59 (1H, d, J ) 8.1 Hz), 8.40-
8.30 (3H, m), 7.98-7.90 (2H, m), 7.29-7.20 (4H, m), 2.45 (3H,
s), 2.44 (4H, t, J ) 7.5 Hz), 1.58-1.46 (4H, m), 1.39-1.25 (8H,
m), 0.89 (6H, t, J ) 6.3 Hz); 13C NMR (125 MHz, acetone-d6)
δ 159.5, 159.4, 158.6, 151.5, 150.0, 147.7, 138.7, 137.0, 133.5,
133.4, 133.1, 132.2, 131.2, 131.1, 130.0, 129.7 (2C), 128.7,
128.6, 127.9, 124.3, 124.1, 119.1, 114.3, 114.14, 114.10, 114.0,
112.6, 103.2, 86.5, 86.1, 31.8 (2C), 30.1 (2C), 29.10, 29.09, 23.0
(2C), 16.4, 14.2 (2C); IR (KBr) ν/cm-1 2228 (CtN), 1718
(CdO), 1495, 1384 (SdO), 1208, 1147 (SdO), 873 (S-O); UV
(MeCN) λ/nm (ꢀ/M-1 cm-1) 279 (41000), 306 (32200), 325
(32600), 445 (2150); MS (EI) m/z 860 (M+, 9%), 109 (100%).
Anal. Calcd for C44H36N4O5S5: C, 61.37; H, 4.21; N, 6.51.
Found: C, 61.75; H, 4.54; N, 6.12.
Com p ou n d 20. The reaction was carried out similarly to
the synthesis of 16, from the acid 19 (0.25 g, 1.0 mmol),
malononitrile (1.0 g, 15 mmol), titanium tetrachloride (1 M
solution in dichloromethane; 5 mL, 5 mmol), and pyridine (0.95
mL, 12.3 mmol). After workup, the orange solution in ethyl
acetate was concentrated and chromatographed on silica gel,
eluting with ethyl acetate/acetone (starting with 4:1 v/v,
gradually changing to 1:4 v/v). The first orange fraction was
evaporated in vacuo, and the residue was redissolved in ethyl
acetate (5 mL); the orange powder 20 as a mixture of Ca and
Na salts (100 mg, ca. 10%) precipitates out of this solution on
C
26H12N4O4S: C, 65.54; H, 2.54; N, 11.76. Found: C, 65.64;
H, 2.60; N, 11.51.
1
storage, mp > 300 °C (dec). H NMR (300 MHz, acetone-d6) δ
N-Meth yl-N-[2-(4-m eth yl-4′,5′-dipen tyltetr ath iafu lvalen -
yl-5-carbonyloxy)ethyl]-13,13,14,14-tetracyanoanthraquino-
d im eth a n e-2-su lfon yla m id e 17. This was obtained using
TCNAQ 15 (110 mg, 0.25 mmol) and carbonyl chloride 6 [from
acid 5 (101 mg, 0.25 mmol)] under the same conditions as
described for 11. After chromatography, the product was
stirred in warm methanol (2 mL) and cooled, and the precipi-
tate was filtered, yielding 17 (26 mg, 13%) as a brown solid,
mp 193-196 °C.
N-Meth yl-N-[2-(4-m eth yl-4′,5′-dipen tyltetr ath iafu lvalen -
yl-5-carbonyloxy)ethyl]-13,13,14,14-tetracyanoanthraquino-
d im eth a n e-2-su lfon yla m id e 17 (a lter n a tive syn th esis).
To a cold (0 °C) solution of carbonyl fluoride 7 (62 mg, 0.153
mmol) and p-(dimethylamino)pyridine (19 mg, 0.156 mmol) in
dry dichloromethane was added TCNAQ derivative 15 (67 mg,
0.153 mmol), and the reaction mixture was stirred at 20 °C
for 24 h, resulting in full dissolution of starting materials.
8.53 (1H, d, J ) 1.2 Hz), 8.42-8.32 (2H, m), 8.29 (1H, d, J )
8.1 Hz), 8.11 (1H, dd, J ) 8.1 and 1.5 Hz), 7.91-7.84 (2H, m);
13C NMR (75 MHz, acetone-d6) δ 187.8, 161.1, 160.8, 144.1,
133.0 (2C), 132.1, 131.7, 131.53, 131.48, 131.36, 128.6, 128.5,
128.0, 127.3, 121.3, 120.0, 114.61, 114.57, 114.54, 114.43, 84.5,
84.4, 52.1; IR (KBr) ν/cm-1 2224 (CtN), 2205 (CtN), 2183
(CtN), 1560, 1542, 1361, 1341, 1325, 1279, 849, 770, 695; CV
1/2
p.a.
E1red -0.37 (2e), E1ox
1.29 V (irreversible). A sample for
X-ray analysis was grown from MeCN solution, concentrated
by slow evaporation of the solvent at 20 °C.
The second yellow fraction which immediately followed the
first one was evaporated, and the residue was refluxed in ethyl
acetate (5 mL), filtered off, and washed with acetone, giving
another product (110 mg), mp > 300 °C (dec), which was not
identified.
(25) â-Alanine was used by analogy with the synthesis of 2-hy-
droxymethyl-11,11,12,12-tetracyanoanthraquinodimethane,23 where
the authors noted that its presence is essential if the hydroxyl group
is present; however, the role of â-alanine was not explained.
Ack n ow led gm en t. We thank EPSRC (D.F.P.) and
NSF (CHE 9905492, V.M.R.) for funding, and the Royal
Society for a Senior Fellowship (J .A.K.H.).

4524 J . Org. Chem., Vol. 66, No. 13, 2001
Perepichka et al.
Su p p or tin g In for m a tion Ava ila ble: Table of crystal data
and details of X-ray experiments; molecular structures of acid
5 and complex 20‚2H2O‚4MeCN; crystal packing pattern of
NMR and 13C NMR spectra of 20. This information is available
free of charge via the Internet at http://pubs.acs.org.
1
TTF-TCNAQ diad 11; SEEPR spectra of 16-•, 18-•, 18+•; H
J O001576+