Octaphenylbiphenylene and dodecaphenyltriptycene

Article abstract of DOI:10.1021/ja0203723

Octaphenylbiphenylene, the expected dimer of tetraphenylbenzyne, has been prepared in low yield by diazotization of 3,4,5,6-tetraphenylanthranilic acid, and its X-ray structure has been determined. The X-ray structure of a second, abnormal dimer of tetrap

Full text of DOI:10.1021/ja0203723

Published on Web 06/12/2002
Octaphenylbiphenylene and Dodecaphenyltriptycene
Jun Lu, Jiajia Zhang, Xianfeng Shen, Douglas M. Ho, and Robert A. Pascal, Jr.*
Contribution from the Department of Chemistry, Princeton UniVersity,
Princeton, New Jersey 08544
Received March 13, 2002
Abstract: Octaphenylbiphenylene, the expected dimer of tetraphenylbenzyne, has been prepared in low
yield by diazotization of 3,4,5,6-tetraphenylanthranilic acid, and its X-ray structure has been determined.
The X-ray structure of a second, abnormal dimer of tetraphenylbenzyne, 1,2,3,8,9,10-hexaphenyldibenzo-
[fg,op]naphthacene has also been determined; this is a saddle-shaped polycyclic aromatic hydrocarbon.
1,2,3,4,5,6,7,8,13,14,15,16-Dodecaphenyltriptycene, perhaps the most crowded triptycene derivative yet
prepared, has been made by the reaction of tetraphenylbenzyne with 1,2,3,4,5,6,7,8-octaphenylanthracene,
which in turn was synthesized in two steps from commercial starting materials. The X-ray structure of the
dodecaphenyltriptycene nonabenzene solvate is a remarkable channel containing structure in which more
than 50% of the unit cell volume is occupied by the benzene molecules.
Introduction
the diazotization, but we did not observe any products formed
by the dimerization of tetraphenylbenzyne itself. Our interest
Polyphenyl polycyclic aromatic molecules and even larger
“polyphenylene nanostructures” have received increased atten-
tion in recent years.1,2 By using both classical and modern
synthetic techniques, one-, two-, or three-dimensional macro-
molecules possessing well-defined conformations and high
stability can be constructed with relative ease, with potential
applications ranging from electronic materials to molecular
separations. We have been especially interested in the synthesis
of perphenyl derivatives of simple polycyclic aromatics (for
example, octaphenylnaphthalene,3,4 decaphenylanthracene,3 oc-
taphenylfluorenone,5 and decaphenylbiphenyl5), studies of which
form the basis for understanding the structures and properties
of more complex polyphenyl molecules.
in such reactions was renewed unexpectedly by the solution of
the structure of an “anomalous crystal”. In 1998, we reported
the synthesis of various methylated octaphenylnaphthalenes4
(such as 3) by the diazotization of 1 (or its methylated
derivatives) in the presence of methylated tetracyclones (such
as 2). The assignment of the stereochemistry of 3 (cis or trans
methyls) was not trivial, and we crystallized many samples in
the hope of obtaining an X-ray structure, but none of the crystals
was satisfactory.
Tetraphenylbenzyne, generated most conveniently by diazo-
tization of 3,4,5,6-tetraphenylanthranilic acid (1), is a convenient
precursor of polyphenyl aromatic hydrocarbons by means of
Diels-Alder reactions with various dienes.3,4,6 However, if the
dienes are sterically hindered, then compound 1 and the products
of its diazotization may react in unusual ways. Several years
ago, we characterized one such product, 1,2,3,4,5,6,7,8-octaphen-
ylcarbazole,7 which appears to result from the reaction of
tetraphenylbenzyne with a nitrogen-containing intermediate from
* Corresponding author. E-mail: snake@chemvax.princeton.edu.
(1) Berresheim, A. J.; Mu¨ller, M.; Mu¨llen, K. Chem. ReV. 1999, 99, 1747-
1785.
(2) Watson, M. D.; Fechtenko¨tter; Mu¨llen, K. Chem. ReV. 2001, 101, 1267-
1300.
A few years after these experiments were performed, our
department acquired a more sensitive diffractometer, and a small
crystal of 3 was found among the old samples that might suffice
for diffraction experiments. To our great surprise, this crystal
was found to contain a 1:2 complex of 3 and 4, and the structures
of these molecules are illustrated in Figure 1. Compound 4 is
(3) Qiao, X.; Padula, M. A.; Ho, D. M.; Vogelaar, N. J.; Schutt, C. E.; Pascal,
R. A., Jr. J. Am. Chem. Soc. 1996, 118, 741-745.
(4) Qiao, X.; Pelczer, I.; Pascal, R. A., Jr. Chirality 1998, 10, 154-158.
(5) Tong, L.; Lau, H.; Ho, D. M.; Pascal, R. A., Jr. J. Am. Chem. Soc. 1998,
120, 6000-6006.
(6) (a) Qiao, X.; Ho, D. M.; Pascal, R. A., Jr. Angew. Chem., Int. Ed. Engl.
1997, 36, 1531-1532. (b) Tong, L.; Ho, D. M.; Vogelaar, N. J.; Schutt, C.
E.; Pascal, R. A., Jr. Tetrahedron Lett. 1997, 38, 7-10. (c) Tong, L.; Ho,
D. M.; Vogelaar, N. J.; Schutt, C. E.; Pascal, R. A., Jr. J. Am. Chem. Soc.
1997, 119, 7291-7302. (d) Pascal, R. A., Jr.; Barnett, L.; Qiao, X.; Ho,
D. M. J. Org. Chem. 2000, 65, 7711-7717. (e) Zhang, J.; Ho, D. M.;
Pascal, R. A., Jr. J. Am. Chem. Soc. 2001, 123, 10919-10926.
(7) Qiao, X.; Ho, D. M.; Pascal, R. A., Jr. J. Org. Chem. 1996, 61, 6748-
6750.
9
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J. AM. CHEM. SOC. 2002, 124, 8035-8041
8035

A R T I C L E S
Lu et al.
a D2 symmetric structure. However, computational studies at
the HF/3-21G level of theory9 indicate that the C2V conformation
is more stable than the D2 conformation by 13.0 kcal/mol,
despite the fact that the latter requires less distortion from
planarity. Indeed, the degree of deformation of the dibenzonaph-
thacene core in 4 is quite large; the average deviation of the
carbon atoms from the mean plane of this C24 hexacycle is 0.63
Å, and the maximum deviation is 1.11 Å. For comparison, the
same values for [7]circulene10 (the paradigmatic saddle-shaped
hydrocarbon) are 0.51 and 1.07 Å. No crystal structure exists
for dibenzo[fg,op]naphthacene or any simple derivative, but HF/
3-21G calculations indicate that the parent hydrocarbon should
be strictly planar with D2h symmetry.
The molecule of 4 is well-ordered in the crystal structure of
the complex, but its companion, the dimethylated octaphenyl-
naphthalene 3, is disordered across a crystallographic center of
inversion. The disorder is such that it is not possible to assign
unambiguously its geometry as cis or trans or a mixture of the
two, which had been the original purpose of the diffraction ex-
periment! The structure refined best with a 55:45 ratio of cis
and trans isomers included in the disorder model, but this result
is not conclusive, and none of the metrical parameters from
this part of the structure should be taken to be particularly
reliable.
In the 1996 report7 from this research group of the formation
of octaphenylcarbazole by diazotization of tetraphenylanthranilic
acid (1), it was noted that “no trace of [octaphenylbiphenylene
(5)] was observed, even though many fractions... were screened
by mass spectrometry.” This result had seemed strange, but the
later observation of 4 provided, for a time, a rationalization for
the absence of 5. If the initial dimerization of tetraphenylbenzyne
(7) gives the diradical 8, then subsequent addition of the radicals
to nearby phenyl groups would lead to intermediate 9, and its
dehydrogenation would yield 4 (oxidants such as isoamyl nitrite
are present in the reaction mixture). The small difference in
the masses of 4 (C60H38, M ) 758) and 5 (C60H40, M ) 760)
might explain the failure of the previous mass spectrometry-
based search for 5.
Figure 1. Molecular structure of 1,2,3,8,9,10-hexaphenyldibenzo[fg,op]-
naphthacene (4, above), and a unit cell diagram of the X-ray structure of
its complex with an octaarylnaphthalene [3‚2(4)‚CH2Cl2, below].
apparently a dimer of tetraphenylbenzyne, but it is not the
“normal” 2+2 dimer octaphenylbiphenylene (5). In this paper
we discuss the structure of 4 and its possible origin, and we
report the synthesis and structure of 5. In addition, we describe
the synthesis of another aryne-derived polyphenyl aromatic
compound, 1,2,3,4,5,6,7,8,13,14,15,16-dodecaphenyltriptycene
(6), as well as the crystal structure of its remarkable benzene
solvate.
Results and Discussion
Dimers of Tetraphenylbenzyne. The X-ray structure of
1,2,3,8,9,10-hexaphenyldibenzo[fg,op]naphthacene (4) shows it
to be a saddle-shaped polycyclic aromatic hydrocarbon pos-
sessing approximate C2V symmetry (see Figure 1). This is
unusual; almost all of the crowded polyphenyl polycyclic
aromatic hydrocarbons that we have prepared exhibit twisting
deformations from planarity,3,5-8 which in this case would yield
In the hope of generating 4 more cleanly, we conducted
several diazotization reactions with 1 in the absence of any
(8) Smyth, N.; Van Engen, D.; Pascal, R. A., Jr. J. Org. Chem. 1990, 55, 1937-
1940.
9
8036 J. AM. CHEM. SOC. VOL. 124, NO. 27, 2002

Octaphenylbiphenylene and Dodecaphenyltriptycene
A R T I C L E S
greater than that predicted for HF/3-21G calculations (1.3°), but
still very modest.
In addition to compound 5, the mass spectra of some fractions
from various diazotization reactions contained the characteristic
m/z 758 ion, which presumably indicates the presence of the
alternative dimer 4, but in none of these was this the principal
component, and compound 4 was never isolated in pure form.
Moreover, not even a tiny amount of pure 4 could be obtained
from the few available crystals of its 2:1 complex with 3; the
two compounds cochromatographed upon TLC in several
solvent systems. Thus, for the present, 4 must remain a minor,
anomalous product known only by means of its fortuitous
crystallization with the naphthalene 3.
Dodecaphenyltriptycene. Among the most dramatic dem-
onstrations of benzyne’s utility is Wittig’s one-step synthesis
of triptycene in 28% yield from anthracene,14 a task that had
required seven steps in Bartlett’s original synthesis.15 When
anthranilic acid is used as a benzyne precursor, the yield of
triptycene can be as high as 75%.16 We have previously prepared
polyphenyl versions of several common aromatic hydrocarbonss
including naphthalene, anthracene,3 biphenyl, fluorene,5 and now
biphenylenesand the synthesis of a polyphenyl version of
triptycene seemed to be a natural extension of this work.
Furthermore, our experience with the crystal structures of very
large, polyphenyl aromatics indicates that most of these
molecules form complex, channel-containing solids,3,6b-d and
we suspected that a polyphenyl triptycene, with three built-in
molecular clefts around a central axis, would likely form crystals
with especially large channels.
Addition of tetraphenylbenzyne (7) to the central ring of
decaphenylanthracene is sterically precluded by the C-9 and
C-10 phenyl substituents, but addition of 7 to 1,2,3,4,5,6,7,8-
octaphenylanthracene (12, Scheme 1) to give 1,2,3,4,5,6,7,8,
13,14,15,16-dodecaphenyltriptycene (6) seemed to be a reason-
able goal. Compound 12 has been reported by Hart and Ok,17
but their synthesis requires seven steps from commercial starting
materials, and the key reaction, a double amination of 1,5-
dihydrobenzo[1,2-d:4,5-d′]bistriazole, proved to be very trouble-
some in our hands. However, a two-step synthesis of octaphen-
ylanthracene 12 (and thus a three-step synthesis of 6) from
commercial starting materials was easy to imagine (Scheme 1).
We found this new synthesis to be short and convenient, but it
does not give high yields.
Figure 2. Molecular structure of octaphenylbiphenylene (5). Thermal
ellipsoids have been drawn at the 50% probability level.
reactive diene. Compound 1 was added to refluxing solutions
of isoamyl nitrite in dichloroethane and heated for an hour, just
as in our past syntheses of octaarylnaphthalenes.3,4,6b-d In those
syntheses, we used excesses of isoamyl nitrite ranging from 1.5
to 5 equiv; 1 to 10 equiv were used in the present experiments.
Several products were characterized by NMR and mass spec-
trometry, including octaphenylcarbazole, 1,2,3,4-tetraphenyl-
benzene, and 2,3,4,5-tetraphenylnitrobenzene. When large ex-
cesses of the nitrite were used, the last of these became the
dominant product. However, only one dimer of tetraphenyl-
benzyne was isolated. Spectroscopic data indicated that this
material was the previously undetected octaphenylbiphenylene
(5), and this was confirmed by an X-ray structure determination
(Figure 2). The yields of 5 were very low, and never more than
5%. We were surprised to find compound 5 at all; there is no
apparent difference between the diazotization conditions em-
ployed in 19967 (when we failed to observe 5) and the present
experiments.
Compound 5 crystallized in the orthorhombic space group
Pbcn, and it lies on a special position, so that the molecule has
exact C2 symmetry (and approximate D2 symmetry). Except for
the presence of the four-membered ring, 5 seems to be relatively
unstrained, and the geometry of its biphenylene nucleus is
extremely similar to those of the parent hydrocarbon11 and its
octamethyl derivative.12,13 For example, the central C(3)-C(4)
bond distance in 5 is 1.521 (4) Å (see Figure 2), while the
average values for this bond in the determinations of biphenylene
itself and octamethylbiphenylene are 1.512 and 1.521 Å,
respectively. However, these smaller molecules are essentially
planar, but 5 exhibits a small twist along its long axis: the
torsion angle C(1A)-C(1)-C(6)-C(6A) is 6.3°. This twist is
There are several close analogues in the literature for the first
step, a double Diels-Alder addition of benzoquinone to
tetracyclone under conditions that promote decarbonylation and
dehydrogenation of the initial adduct, and the yields are often
good.18 However, in this particular case, the isolated yield of
pure, crystalline octaphenylanthraquinone (11) was never above
10%. Fortunately, the starting materials are inexpensive, and
in an initial synthetic step, the losses are not so painful. Quinone
11 was resistant to catalytic hydrogenation, and hydride reagents
gave mixtures of oxygenated reduction products,19 but it was
reduced to the desired anthracene 12 by boiling in hydriodic
(9) Hehre, W. J.; Radom, L.; Schleyer, P. v. R.; Pople, J. A. Ab Initio Molecular
Orbital Theory; John Wiley & Sons: New York, 1986; pp 63-100.
(10) (a) Yamamoto, K.; Harada, T.; Nakazaki, M.; Nakao, T.; Kai, Y.; Harada,
S.; Kasai, N. J. Am. Chem. Soc. 1983, 105, 7171-7172. (b) Yamamoto,
K.; Harada, T.; Okamoto, Y.; Chikamatsu, H.; Nakazaki, M.; Kai, Y.;
Nakao, T.; Tanaka, M.; Harada, S.; Kasai, N. J. Am. Chem. Soc. 1988,
110, 3578-3584.
(11) Fawcett, J. K.; Trotter, J. Acta Crystallogr. 1966, 20, 87-93.
(12) Jones, J. B.; Brown, D. S.; Hales, K. A.; Massey, A. G. Acta Crystallogr.,
Sect. C 1988, 44, 1757-1759.
(13) Le Magueres, P.; Lindeman, S. V.; Kochi, J. K. Organometallics 2001,
20, 115-125.
(14) (a) Wittig, G. Org. Synth. 1959, 39, 75-77. (b) Wittig, G. Organic
Syntheses; Wiley: New York, 1963; Collect. Vol. IV, pp 964-966.
(15) Bartlett, P. D.; Ryan, M. J.; Cohen, S. G. J. Am. Chem. Soc. 1942, 64,
2649-2653.
(16) Friedman, L.; Logullo, F. M. J. Am. Chem. Soc. 1963, 85, 1549.
(17) Hart, H.; Ok, D. J. Org. Chem. 1986, 51, 979-986.
(18) Ogliaruso, M. A.; Romanelli, M. G.; Becker, E. I. Chem ReV. 1965, 65,
261-367.
9
J. AM. CHEM. SOC. VOL. 124, NO. 27, 2002 8037

A R T I C L E S
Lu et al.
Scheme 1
acid and acetic acid for prolonged periods.20 Two weeks of
reaction gave 12 in 32% yield. Addition of tetraphenylbenzyne
to 12 gave the desired dodecaphenyltriphenylene 6 in 11% yield,
a satisfactory result given the steric crowding in the product.21
Compound 6 is soluble in a variety of organic solvents and
it crystallizes readily, always forming structures with substantial
amounts of included solvent. Two such structures are reported
here: the dichloromethane and benzene solvates. Crystallization
from CH2Cl2-MeOH gave monoclinic crystals, space group
P21/c, with Z ) 8; that is, there are two independent molecules
of 6 in the asymmetric unit. In addition, 20.5% of the unit cell
volume is occupied by dichloromethane molecules which are
disordered to varying degrees, but this is not an unusual degree
of solvation for a molecular solid. More impressive are the
crystals obtained from benzene; these are orthorhombic, space
group Pna21. The asymmetric unit contains a single molecule
of 6 along with nine molecules of benzene; the included solvent
occupies 50.5% of the unit cell volume. With 12 phenyl
substituents, 6 is by far the most highly substituted triptycene
to have been crystallographically characterized, and its molecular
structure is illustrated in Figure 3. The Cambridge Structural
Database22 (CSD) contains only three triptycene derivatives with
as many as six substituents.23,24 One other triptycene with 12
Figure 3. Molecular structure of 1,2,3,4,5,6,7,8,13,14,15,16-dodecaphen-
yltriptycene (6), taken from the X-ray structure of its benzene solvate (6‚
9C6H6). Thermal ellipsoids have been drawn at the 50% probability level.
substituents is known, Hart’s “supertriptycene”,25 in which there
are six 9,10-anthradiyl moieties fused to a central triptycene,
but he reports that the solvent molecules included in the crystals
made it impossible to solve the crystal structure.26 It seems that
we were more fortunate!
The 12 phenyl groups of 6 are accommodated with little
distortion of the triptycene core.21 For example, the 12 crys-
tallographically independent bridgehead-arene bonds in the
dichloromethane solvate of 6 average 1.531 ( 0.007 Å, and
this value is 1.531 ( 0.008 Å for the six independent bonds in
the benzene solvate. For comparison, two existing X-ray
structures of triptycene itself yield average distances of 1.53 (
0.03 Å27 and 1.526 ( 0.014 Å28 for the same bonds. In all three
determinations of 6, the 12 phenyl rings are interlocked in the
same fashion, so that the molecules have approximately D3, and
not D3h, symmetry. There is a roughly cylindrical cavity above
each of the bridgehead hydrogens of 6, but this is too small to
be occupied by a guest solvent molecule, and substitution of
(19) Zhang, J.; Ho, D. M.; Pascal, R. A., Jr. Tetrahedron Lett. 1999, 40, 3859-
3862.
(20) Konieczny, M.; Harvey, R. G. J. Org. Chem. 1979, 44, 4813-4816.
(21) A referee noted that the low yield in the synthesis of 6 seems inconsistent
with the molecule’s apparent lack of strain. However, such low strain applies
only to the ground state of 6 in which the phenyl groups are nicely
interdigitated; in the transition state leading to the formation of 6, there
may be substantial conflicts between the phenyls of the precursors.
(22) Allen, F. H.; Kennard, O.; Taylor, R. Acc. Chem. Res. 1983, 16, 146-
153.
(25) Shahlai, K.; Hart, H. J. Am. Chem. Soc. 1990, 112, 3687-3688.
(26) Hart, H. Pure Appl. Chem. 1993, 65, 27-34.
(27) Anzenhofer, K.; de Boer, J. J. Z. Kristallogr. 1970, 131, 103-113.
(28) Veen, E. M.; Postma, P. M.; Jonkman, H. T.; Spek, A. L.; Feringa, B. L.
Chem. Commun. 1999, 1709-1710.
(23) Bashir-Hashemi, A.; Hart, H.; Ward, D. L. J. Am. Chem. Soc. 1986, 108,
6675-6679.
(24) Toyota, S.; Endo, M.; Teruhi, M.; Noda, Y.; Oki, M.; Yamasaki, M.;
Shibahara, T. Bull. Chem. Soc. Jpn. 1993, 66, 2088-2096.
9
8038 J. AM. CHEM. SOC. VOL. 124, NO. 27, 2002

Octaphenylbiphenylene and Dodecaphenyltriptycene
A R T I C L E S
Figure 4. Stereoview of the crystal structure of 6‚9C6H6 viewed down the crystallographic a axis. The molecules of 6 are shown as simple line drawings;
the benzene molecules as ball-and-stick drawings.
Table 1. Exceptional Examples of Crystallographically
the bridgehead hydrogens with larger atoms would undoubtedly
be difficult.
Characterized Organic Binary Solvates (A‚nS)a
vol %
CSD
As noted above, the crystals of 6 from benzene are highly
solvated. The solvent is located mainly in infinite channels par-
allel to the a axis, which are illustrated in Figure 4. These chan-
nels have roughly elliptical cross sections with major and minor
axes of 25 and 10 Å, respectively. A careful examination of
the structure shows that six of the nine crystallographically in-
dependent benzene molecules are arranged in three infinite col-
umns within the channels, and the remaining three benzenes
are found in the three V-shaped clefts of the dodecaphenyltrip-
tycene. The vast majority of the benzene-benzene and benzene-
phenyl contacts are of the edge-to-face or edge-to-edge variety;
there are few interactions that may be characterized as π-stack-
ing.
Nearly all of our crystals of very large polyphenyl aromatic
compounds (with >100 carbons6b-d,29) contain solvent of
crystallization as part of the structure, but in none does the
primary molecule occupy less than 50% of the unit cell volume,
which is the case for 6‚9C6H6. The fact that the benzene
molecules are, for the most part, well-ordered is also unusual.
Wondering how common were such highly solvated structures,
we conducted a search of the CSD for two-component organic
crystals which contained large proportions of solvent of crystal-
lization. The results are presented in Table 1.30 A detailed
analysis of these structures is inappropriate here (the interested
reader can access them easily by way of the CSD refcodes),
but one observation stands out. In the great majority of these
exceptionally solvated crystals, both components are polar
molecules capable of hydrogen bonding (at least as donors or
acceptors). Thus, for example, the chloroform molecules in
entries f, g, and h30e,h,o donate hydrogen bonds to oxygen or
nitrogen atoms in the primary organic components. A pure
hydrocarbon binary system, such as the present case (entry b),
with 50% solvent by volume is extremely unusual. Only two
other structures in Table 1 lack any polar functionality, the
dodecaphenylcyclohexasilane benzene solvate (c)27a and the C60
cyclohexane solvate (j).30s It is interesting that both b and c
contain large polyphenyl molecules. Perhaps their large surface
area permits the formation of particularly favorable van der
solvent
benzene
benzene
benzene
benzonitrile
tert-butanol
chloroform
chloroform
chloroform
2-chlorophenol C40H26N8‚5C6H5ClO
cyclohexane
DMA
DMSO
m DMSO
DMSO
ethyl acetate
propionic acid
propionic acid
pyridine
pyridine
pyridine
reported formula
non-HA/non-H solventb refcodec
nS
a
b
c
d
e
f
g
h
i
C
C
C
C
C
C
C
C
17H20O10‚C6H6
92H62‚9C6H6
27/24 ) 1.12
92/54 ) 1.70
78/42 ) 1.86
56/56 ) 1.00
20/20 ) 1.00
54/48 ) 1.13
30/16 ) 1.88
30/16 ) 1.88
48/40 ) 1.20
60/72 ) 0.82
60.0 CEPJOW
50.5
47.1 BASVIA
63.2 NIPXIT
64.3 XEHPEF
57.9 FUJGOG
56.6 HUFWAG
50.2 WAQMIK
57.3 YOVVEK
81.9e YOLSOH
d
72H60Si6‚7C6H6
44H30N4O8‚7C5H5N
18H20O2‚4C4H10
O
48H40O6‚12CHCl3
24H12N6‚4CHCl3
26H40N4‚4CHCl3
j
k
l
C60‚12C6H12
C
C
C
C
C
C
C
C
C
C
C
C
C
C
160H136O24‚18C4H9NO 184/108 ) 1.70 52.9 VURBUF
52H40O12‚18C2H6SO 64/72 ) 0.89
52H40O12‚12C2H6SO 64/48 ) 1.33
52H40O12‚10C2H6SO 64/40 ) 1.60
44H30N4O8‚5C4H8O2 56/30 ) 1.87
20H16N4O4Si‚4C3H6O2 29/20 ) 1.45
53H32N4O4‚8C3H6O2 61/40 ) 1.52
52H40O12‚14C5H5N
32H32O8‚6C5H5N
18H142N4O8S2‚4C5H5N 46/24 ) 1.92
88H112O8‚8C5H5N 96/48 ) 2.00
71.3 RETKAC
64.1 GIYTAJ
58.5 GIYSUC
53.0 NIPXEP
57.7 YINJOU
51.2 VOJFEF
68.6 RETKEG
59.3 NEYLOS
54.3 GOWVAP
46.5 LAYKUR
51.3 DEXQIG
46.1 QEFCEJ
43.1 FIZFEZ
n
o
p
q
r
s
t
u
v
64/84 ) 0.76
40/36 ) 1.11
pyridine
TFA
w TFA
TFA
25H35N3O4‚4C2HF3O2 32/28 ) 1.14
28H18N2O6‚4C2HF3O2 36/28 ) 1.29
40H26N4‚4C2HF3O2
x
44/28 ) 1.57
a Criteria for inclusion in this table: (1) the structures are binary solvates
with the composition A‚nS, where A and S are neutral organic molecules
containing no metal atoms and n g 4; (2) the ratio of non-H atoms in A to
those in nS is 2 or less; and (3) the atomic coordinates of the structure (at
least for the primary molecule A) have been deposited in the CSD (ref 21).
b This quantity is the percent “solvent accessible volume” as calculated by
the VOID/SOLV option in PLATON (ref 34) when only the primary
molecule (A) is included in the crystallographic input file. c See ref 30 for
the full citations. d This work. e The deposited coordinates for this structure
are idealized C60 and cyclohexane molecules, and no R factor is given, so
the volume calculation must be considered approximate at best.
Waals interactions between the primary molecules and the
included benzene, and their relative rigidity in turn helps to
support the benzene molecules in an ordered array.
Conclusion
In sum, tetraphenylbenzyne undergoes “expected” reactions
with itself, to form octaphenylbiphenylene (5), and with
1,2,3,4,5,6,7,8-octaphenylanthracene (12), to form dodecaphen-
yltriptycene 6. Compounds 5 and 6 are two new members of
the growing class of polyphenyl derivatives of simple polycyclic
aromatics. The yields in these syntheses are lower than those
(29) Pascal, R. A., Jr.; Hayashi, N.; Ho, D. M. Tetrahedron 2001, 57, 3549-
3555.
9
J. AM. CHEM. SOC. VOL. 124, NO. 27, 2002 8039

A R T I C L E S
Lu et al.
Table 2. Crystallographic Data for Compounds 3-6
3‚2(4)‚CH Cl2
5‚2CH Cl2
6‚CH Cl2
6‚9C6H
6
2
2
2
chemical formula
C60H44‚2C60H38
2367.69
C60H40‚2CH2Cl2‚CH2Cl2
C92H62‚CH2Cl2
1252.34
C92H62‚9C6H6
formula weight
930.77
1870.39
crystal size (mm3)
0.15 × 0.10 × 0.05
P1h (No. 2)
13.8946 (6)
15.1490 (9)
17.4672 (10)
75.587 (2)
67.113 (3)
70.637 (3)
3165.0 (3)
1
0.22 × 0.05 × 0.05
Pbcn (No. 60)
18.6482 (5)
24.2381 (8)
10.5573 (3)
90
0.20 × 0.12 × 0.05
P21/c (No. 14)
19.2738 (4)
28.5548 (5)
32.3310 (5)
90
125.4847 (8)
90
14488.9 (5)
8
0.42 × 0.35 × 0.07
space group
a, Å
b, Å
Pna21 (No. 33)
24.155 (2)
17.016 (1)
26.221 (2)
90
c, Å
R, deg
â, deg
γ, deg
V, Å3
Z
90
90
90
90
10778 (1)
4
1.153
0.065
200 (2)
22.5
4771.9 (2)
4
1.296
0.289
200 (2)
25.0
F
calcd, g/cm3
1.242
0.111
200 (2)
22.5
1.148
0.136
200 (2)
22.5
m, mm-1
T, K
θmax, deg
no. of reflcns
total
unique
obsd [I > 2s(I)]
R(F) (obsd data)a
wR(F2) (obsd data)a
S (obsd data)a
R(F) (all data)a
wR(F2) (all data)a
S (all data)a
25504
8242
5443
0.097
0.208
1.21
0.147
0.235
1.09
20081
4217
2767
0.063
0.153
1.08
0.104
0.180
1.02
82861
18933
12780
0.075
0.207
1.17
0.112
0.227
1.04
29102
13354
9682
0.060
0.118
1.11
0.099
0.139
1.06
R(F) ) ∑||Fo| - |Fc||/∑|Fo|; wR(F2) ) [∑w(Fo2 - Fc )2/∑w(Fo )2]1/2; ∑ ) goodness-of-fit on F2 ) [∑w(Fo2 - Fc )2/(n - p)]1/2, where n is the number
a
2
2
2
of reflections and p is the number of parameters refined.
extracted with chloroform (100 mL). The extract was washed twice
each with saturated NaHCO3 and water, dried over Na2SO4, and
concentrated to dryness. The residue was chromatographed on a silica
gel column (solvent, 3:1 hexanes-benzene), and the fraction with Rf
0.28 (silica gel TLC; solvent, 3:1 hexanes-benzene) was collected.
Further purification by preparative TLC in the same solvent gave
for the parent hydrocarbons, due probably to the steric restric-
tions imposed by the many phenyl groups. However, the extra
phenyl groups also give an opportunity for unusual reactivity,
as in the formation of dimer 4 in which three new carbon-
carbon bonds have been made. All of these polyphenyl aromatic
compounds are prone to form solvated crystals, of which 6‚
9C6H6 is an exceptional example.
1
compound 5 (11 mg, 0.014 mmol, 2.6%); mp 265-267 °C. H NMR
(CDCl3) δ 6.44-6.50 (m, 16 H), 6.62-6.65 (m, 8 H), 6.71 (t, J ) 6
Hz, 4 H), 6.79-6.84 (m, 12 H); 13C NMR (CDCl3) δ 125.5, 126.2,
126.7, 126.9, 129.3, 131.7, 132.3, 137.2, 140.3, 141.7, 148.0 (11 of 11
expected resonances observed); MS (EI) m/z 760 (M+, 100), 736 (M
- C2, 30), 682 (M - C6H6, 2), 660 (M - C2 - C6H6, 36); exact mass
760.3138, calcd for C60H40 760.3130.
Experimental Section
Octaphenylbiphenylene (5). A solution of isoamyl nitrite (0.15 mL,
1.1 mmol) in 1,2-dichloroethane (10 mL) was heated to reflux under
argon. A mixture of 3,4,5,6-tetraphenylanthranilic acid3 (1, 246 mg,
0.56 mmol) in dichloroethane (30 mL) was added dropwise over 1 h,
and heating was continued for 3 h. Ethanol (8 mL) and 1% NaOH (32
mL) were added to quench the reaction, and the resulting mixture was
Octaphenylanthraquinone (11). Tetracyclone (10, 10.00 g, 26.0
mmol) and p-benzoquinone (1.41 g, 13.0 mmol) were heated in
refluxing nitrobenzene (20 mL) for 22 h. After cooling, methanol (∼40
mL) was added, and the resulting dark precipitate was collected by
filtration. This material was air-dried, and then it was extracted with
hot benzene for 5 h (Soxhlet). The extract was concentrated and then
chromatographed on a silica gel column (solvent, benzene), and the
fraction with Rf 0.37 was collected. Crystallization of this material from
benzene-methanol gave pure compound 11 (824 mg, 1.01 mmol,
7.8%); mp 391-392 °C. 1H NMR (CDCl3) δ 6.71 (dd, J ) 8, 2 Hz, 8
H), 6.80-6.84 (m, 12 H), 6.92-6.98 (m, 20 H); 13C NMR (CDCl3) δ
125.9, 126.1, 126.7, 126.9, 130.3, 130.7, 135.4, 137.8, 138.7, 139.7,
146.3, 188.6 (12 of 12 expected resonances); MS (EI) m/z 816 (M+,
100); exact mass 816.2985, calcd for C62H40O2 816.3030.
(30) References for the structures in Table 1: (a) BASVIA: Drager, M.; Walter,
K. G. Z. Anorg. Allg. Chem. 1981, 479, 65-74. (b) CEPJOW: Radcliffe,
M. D.; Gutierrez, A.; Blount, J. F.; Mislow, K. J. Am. Chem. Soc. 1984,
106, 682-687. (c) DEXQIG: Abele, S.; Vogtli, K.; Seebach, D. HelV.
Chim. Acta 1999, 82, 1539-1558. (d) FIZFEZ: Hall, D. M.; Hwang, H.-
Y.; Insole, J. M.; Walker, N. P. C. J. Chem. Soc., Perkin Trans. 1 1987,
1763-1769. (e) FUJGOG: Kohnke, F. H.; Slawin, A. M. Z.; Stoddart, J.
F.; Williams, D. J. Angew. Chem., Int. Ed. Engl. 1987, 26, 892-894. (f)
GIYSUC, GIYTAJ: Shivanyuk, A.; Bohmer, V.; Paulus, E. F. Gazz. Chim.
Ital. 1997, 127, 741-747. (g) GOWVAP: Bock, H.; Nagel, N.; Eller P. Z.
Naturforsch., Teil B 1999, 54, 501-514. (h) HUFWAG: Alfonso, M.;
Stoeckli-Evans, H. Acta Crystallogr., Sect. E (Structure Rep. Online) 2001,
57, o242-o244. (i) LAYKUR: Czugler, M.; Tisza, S.; Speier, G. J.
Inclusion Phenom. Macrocycl. Chem. 1991, 11, 323-331. (j) NEYLOS:
MacGillivray, L. R.; Atwood, J. L. J. Am. Chem. Soc. 1997, 119, 6931-
6932. (k) NIPXIT, NIPXEP: Bhyrappa, P.; Wilson, S. R.; Suslick, K. S.
J. Am. Chem. Soc. 1997, 119, 8492-8502. (l) RETKAC, RETKEG:,
Shivanyuk, A.; Paulus, E. F.; Bohmer, V.; Vogt, W. Angew. Chem., Int.
Ed. Engl. 1997, 36, 1301-1303. (m) VOJFEF: Simard, M.; Su, D.; Wuest,
J. D. J. Am. Chem. Soc. 1991, 113, 4696-4698. (n) VURBUF: Cram, D.
J.; Blanda, M. T.; Paek, K.; Knobler, C. B. J. Am. Chem. Soc. 1992, 114,
7765-7773. (o) WAQMIK: Lloyd, J.; Vatsadze, S. Z.; Robson, D. A.;
Blake, A. J.; Mountford, D. P. J. Organomet. Chem. 1999, 591, 114-126.
(p) XEHPEF: Gorbitz, C. H.; Hersleth H.-P. Acta Crystallogr., Sect. B
2000, 56, 1094-1102. (q) YINJOU: Wang, X.; Simard, M.; Wuest, J. D.
J. Am. Chem. Soc. 1994, 116, 12119-12120. (r) YOVVEK: Krupitsky,
H.; Stein, Z.; Goldberg, I.; Strouse, C. E. J. Inclusion Phenom. Macrocycl.
Chem. 1994, 18, 177-192. (s) YOLSOH: Jansen, M.; Waidmann, G. Z.
Anorg. Allg. Chem. 1995, 621, 14-18.
1,2,3,4,5,6,7,8-Octaphenylanthracene (12). Compound 11 (220 mg,
0.270 mmol) was added to acetic acid (100 mL), and the mixture was
heated to reflux. Hydriodic acid (10 mL) was added, and heating was
continued for 2 weeks under argon, with the addition of more hydriodic
acid on three occasions (5 mL each). The hot solution was poured into
8% sodium bisulfite (200 mL), and the resulting yellow precipitate was
collected by filtration and washed with water. This material was
chromatographed on a silica gel column (solvent, toluene), and the
fraction with Rf 0.92 was collected and concentrated to dryness to give
compound 12 (67.2 mg, 0.086 mmol, 32%); mp 369-370 °C (lit.17
9
8040 J. AM. CHEM. SOC. VOL. 124, NO. 27, 2002

Octaphenylbiphenylene and Dodecaphenyltriptycene
A R T I C L E S
1
mp 415-417 °C). H NMR (CDCl3) δ 6.69-6.72 (m, 8 H), 6.76-
12 H), 6.61-6.70 (m, 24 H), 6.72-6.79 (m, 18 H), 6.95 (tt, J ) 7, 2
Hz, 6 H); 13C NMR (CDCl3) δ 47.0, 125.1, 125.9, 126.7, 127.4, 131.1,
132.0, 137.1, 138.6, 141.2, 143.6 (11 of 12 expected resonances); MS
(FAB) m/z 1168 (M + H [12C9113C1], 100), 788 (38).
6.80 (m, 12 H), 6.87-6.89 (m, 8 H), 6.92-6.97 (m, 12 H); 13C NMR
(CDCl3) δ 125.3, 126.0, 126.7, 127.5, 130.6, 131.6, 136.6, 139.0, 139.1,
139.9, 140.9 (11 of 12 expected resonances); MS (FAB) m/z 786 (M+,
100), 711 (22), 551 (82).
General X-ray Crystallographic Procedures. X-ray data were
collected by using graphite monochromated Mo Ka radiation (0.71073
Å) on a Nonius KappaCCD diffractometer. The diffraction data were
processed by using the program DENZO.31 All structures were solved
by direct methods with Siemens SHELXTL,32 and all were refined by
full-matrix least squares on F2 with SHELXTL. All non-hydrogen atoms
were refined anisotropically, and hydrogens were included with a riding
model. The structure of 6‚CH2Cl2 contained some highly disordered
solvent of crystallization; this was treated by using the SQUEEZE/
BYPASS procedure33 implemented in PLATON-96.34 Specific crystal,
reflection, and refinement data are contained in Table 2, and full details
are provided in the Supporting Information.
Computational Studies. All ab initio calculations were performed
by using GAUSSIAN 98,35 and its built-in default thresholds for wave
function and gradient convergence were employed. Analytical frequency
calculations established that all of the conformations discussed represent
true potential minima.
1,2,3,4,5,6,7,8,13,14,15,16-Dodecaphenyltriptycene (6). A solution
of compound 12 (67 mg, 0.085 mmol) in 1,2-dichloroethane (15 mL)
was heated to reflux. Isoamyl nitrite (19 mL, 0.14 mmol) in dichlo-
roethane (1 mL) was added, and then compound 1 (62 mg, 0.14 mmol)
in dichloroethane (15 mL) was added over 25 min. After 2 h, ethanol
(6 mL) and 1% NaOH (10 mL) were added to quench the reaction,
and the resulting mixture was extracted twice with chloroform. The
combined extracts were washed with saturated NaHCO3, dried over
Na2SO4, and concentrated to dryness. The residue was subjected twice
to preparative TLC (solvents, 1:1 hexanes-benzene and 5:1 hexanes-
ethyl acetate) to give compound 6 (Rf 0.53, 5:1 hexanes-ethyl acetate),
which was recrystallized from CH2Cl2-MeOH (10.7 mg, 0.0092 mmol,
11%); mp >450 °C. 1H NMR (CDCl3) δ 6.38 (s, 2 H), 6.55-6.58 (m,
(31) Otwinowski, Z.; Minor, W. Methods Enzymol. 1997, 276, 307-326.
(32) Sheldrick, G. M. SHELXTL, Version 5; Siemens Analytical X-ray Instru-
ments:, Madison, WI, 1996.
(33) Van der Sluis, P.; Spek, A. L. Acta Crystallogr., Sect. A 1990, 46, 194-
201.
Acknowledgment. This work was supported by National
Science Foundation Grant CHE-0077990, which is gratefully
acknowledged.
(34) Spek, A. L. Acta Crystallogr., Sect. A 1990, 46, C34.
(35) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M.
A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery, J. A., Jr.; Stratmann,
R. E.; Burant, J. C.; Dapprich, S.; Millam, J. M.; Daniels, A. D.; Kudin,
K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.; Barone, V.; Cossi, M.; Cammi,
R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford, S.; Ochterski, J.;
Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.; Malick, D. K.;
Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Cioslowski, J.; Ortiz,
J. V.; Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.;
Gomperts, R.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng,
C. Y.; Nanayakkara, A.; Gonzalez, C.; Challacombe, M.; Gill, P. M. W.;
Johnson, B. G.; Chen, W.; Wong, M. W.; Andres, J. L.; Head-Gordon,
M.; Replogle, E. S.; Pople, J. A. Gaussian; Gaussian, Inc.: Pittsburgh,
PA, 1998.
Supporting Information Available: A crystallographic in-
formation file (CIF), containing the full X-ray structural data
for structures 3‚2(4)‚CH2Cl2, 5‚2CH2Cl2, 6‚CH2Cl2, and 6‚
9C6H6. This material is available free of charge via the Internet
at http://pubs.acs.org.
JA0203723
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J. AM. CHEM. SOC. VOL. 124, NO. 27, 2002 8041