Octaphenylnaphthalene and decaphenylanthracene

Article abstract of DOI:10.1021/ja953669s

Octaphenylnaphthalene (2) was synthesized by the addition of tetraphenylbenzyne to tetraphenylcyclopentadienone, and decaphenylanthracene (3) was synthesized by addition of the same aryne to hexapenylisobenzofuran followed by deoxygenation of the adduct.T

Full text of DOI:10.1021/ja953669s

J. Am. Chem. Soc. 1996, 118, 741-745
741
Octaphenylnaphthalene and Decaphenylanthracene
Xiaoxin Qiao, Michael A. Padula, Douglas M. Ho, Nancy J. Vogelaar,
Clarence E. Schutt, and Robert A. Pascal, Jr.*
Contribution from the Department of Chemistry, Princeton UniVersity,
Princeton, New Jersey 08544
ReceiVed October 31, 1995X
Abstract: Octaphenylnaphthalene (2) was synthesized by the addition of tetraphenylbenzyne to tetraphenylcyclo-
pentadienone, and decaphenylanthracene (3) was synthesized by the addition of the same aryne to hexaphenyl-
isobenzofuran followed by deoxygenation of the adduct. The structures of both compounds were determined by
X-ray analysis. Compound 2 adopts a conformation of approximate Ci symmetry with a slightly undulating naphthalene
nucleus, but compound 3 exhibits C2 (and approximate D2) symmetry with a 63° twist of the central anthracene.
Introduction
gently twisted, with C2 or D2 symmetry and end-to-end twists7
on the order of 20-30°, while the naphthalene cores of a variety
of octakis(arylthio)- and octakis(alkylthio)naphthalenes (7)8 are
either twisted or adopt an undulating structure of Ci symmetry.
No X-ray structures exist of simple decasubstituted anthracenes,
but compound 8 and its relatives, in which several “substituents”
are fused benzene rings, are highly distorted, with end-to-end
twists of 60-70°.2a-c However, these compounds are not
properly anthracenes at all, since the corner benzo groups are
intimate components of the polycyclic aromatic π-electron
system. On the other hand, in decaphenylanthracene the mean
planes of the phenyl substituents will be tilted out of the plane
of the anthracene, reducing conjugation with the acene π-system.
Thus any electronic effects due to simple steric distortion of
the anthracene core may be more clearly discernible in
compound 3, making it a most attractive target for synthesis.
We now report the preparation and structural characterization
of both octaphenylnaphthalene and decaphenylanthracene.
Hexaphenylbenzene (1) was first prepared in 1933 by the
cycloaddition of tetraphenylcyclopentadienone and diphenyl-
acetylene,1 a classic synthesis now repeated thousands of times
annually in undergraduate laboratories. A natural extension of
this work might have been the synthesis of other perphenyl
aromatic compounds, but after more than 60 years, 1 and its
many simple derivatives remain the only perphenyl benzenoid
aromatics to have been prepared.
Results and Discussion
Syntheses. The syntheses of compounds 2 and 3 are outlined
in Scheme 1. The key intermediate in both is 3,4,5,6-
tetraphenylanthranilic acid (11), which we expected to be an
excellent precursor of tetraphenylbenzyne, a species sufficiently
reactive to enable the formation of the crowded carbon skeletons
of 2 and 3. The preparation of 11, and from it octaphenyl-
naphthalene, was entirely straightforward. The Diels-Alder
reaction of tetracyclone (9) and maleimide, conducted in
refluxing nitrobenzene to promote both decarbonylation and
dehydrogenation of the initial adduct, gave the imide 10.
Hofmann rearrangement of 10 in methanol, followed by
hydrolysis of the resulting urethane, produced the desired
anthranilate 11 in 42% overall yield from 9. Finally, diazoti-
zation of 11 in dichloroethane in the presence of more
tetracyclone gave octaphenylnaphthalene in 62% yield, which
is quite remarkable given the steric bulk of the two reactants.
The synthesis of decaphenylanthracene, although nearly as
short, was much less efficient. In our initial experiments,
Our continuing interest in sterically congested polycyclic
aromatic compounds2 led us to consider the structures of the
perphenylacenes, of which the simplest examples are octaphen-
ylnaphthalene (2) and decaphenylanthracene (3). The central
ring of hexaphenylbenzene shows only slight deviations from
planarity in the solid state,3 but the severe peri interactions in
2 and 3 should force substantial distortions of their acene cores.
Indeed, the X-ray crystal structures of octachloro- (4),4 octa-
bromo- (5),5 and octamethylnaphthalene (6)6 show them to be
X Abstract published in AdVance ACS Abstracts, January 15, 1996.
(1) Dilthey, W.; Schommer, W.; Trosken, O. Chem. Ber. 1933, 66, 1627-
1628.
(2) (a) Pascal, R. A., Jr.; McMillan, W. D.; Van Engen, D. J. Am. Chem.
Soc. 1986, 108, 5652-5653. (b) Pascal, R. A., Jr.; McMillan, W. D.; Van
Engen, D.; Eason, R. G. J. Am. Chem. Soc. 1987, 109, 4660-4665. (c)
Smyth, N.; Van Engen, D.; Pascal, R. A., Jr. J. Org. Chem. 1990, 55, 1937-
1940. (d) Shibata, K.; Kulkarni, A. A.; Ho, D. M.; Pascal, R. A., Jr. J. Am.
Chem. Soc. 1994, 116, 5983-5984. (e) Shibata, K.; Kulkarni, A. A.; Ho,
D. M.; Pascal, R. A., Jr. J. Org. Chem. 1995, 60, 428-434.
(3) Bart, J. C. J. Acta Crystallogr., Sect. B 1968, 24, 1277-1287.
(4) Herbstein, F. H. Acta Crystallogr., Sect. B 1979, 35, 1661-1670.
(5) Brady, J. H.; Redhouse, A. D.; Wakefield, B. J. J. Chem. Res. 1982,
1541-1554.
(6) Sim, G. A. Acta Crystallogr., Sect. B 1982, 38, 623-625.
(7) See note 17 in ref 2b for the definition of “end-to-end twist”.
(8) (a) Barbour, R. H.; Freer, A. A.; MacNicol, D. D. J. Chem. Soc.,
Chem. Commun. 1983, 362-363. (b) MacNicol, D. D.; Mallinson, P. R.;
Robertson, C. D. J. Chem. Soc., Chem. Commun. 1985, 1649-1651. (c)
MacNicol, D. D.; McGregor, W. M.; Mallinson, P. R.; Robertson, C. D. J.
Chem. Soc., Perkin Trans. 1 1991, 3380-3382. (d) For a recent discussion
of polymorphism in crystals, see: Dunitz, J. D.; Bernstein, J. Acc. Chem.
Res. 1995, 28, 193-200.
0002-7863/96/1518-0741$12.00/0 © 1996 American Chemical Society

742 J. Am. Chem. Soc., Vol. 118, No. 4, 1996
Qiao et al.
Scheme 1
Figure 1. X-ray structure of 12‚CHCl3. Thermal ellipsoids have been
drawn at the 50% probability level, and all hydrogens but that of the
chloroform have been omitted for clarity. The CHCl3 molecule is
hydrogen bonded to the oxygen of 12.
compound 11 was diazotized in the presence of 2,5-diphenyl-
furan to give the adduct 12. All attempts to complete the carbon
skeleton of 3 by Diels-Alder reaction of 12 with tetracyclone
were unsuccessful, even when conducted at elevated tempera-
tures and in the absence of solvent. Indeed, the X-ray crystal
structure of compound 12 (Figure 1) shows the olefin to be
extremely hindered by the surrounding phenyl groups.
The simple, convenient preparation of hexaphenylisobenzo-
furan (13) by Ried and Bonnighausen9 provided an alternative.
Although these authors had characterized this compound only
by its melting point, we found their procedure to yield pure
material which did, however, slowly decompose if stored at
room temperature. Diazotization of 11 in the presence of 13
gave an 8% yield of the decaphenylanthracene oxide 14.
Presumably this meager yield reflects the reduced reactivity of
a hexaphenylisobenzofuran. The final step, deoxygenation of
the adduct 14, was equally difficult, again no doubt due to steric
encumbrance by the phenyl substituents. Simple heating in
diglyme10 and reduction with low-valent titanium11 were unsuc-
cessful, but treatment of 14 with excess activated zinc dust in
refluxing acetic acid gave a 3% yield of the desired hydrocarbon.
Fortunately, compound 3 was easily isolated by preparative
TLC, and it was possible to recover most of the precursor 14
for recycling as required.
Figure 2. X-ray structures of octaphenylnaphthalene (above) and
decaphenylanthracene (below). Thermal ellipsoids are drawn at the 50%
probability level, and hydrogen atoms have been omitted for clarity.
Structure of Octaphenylnaphthalene. The molecular struc-
ture of 2 was established by X-ray analysis. The crystals are
orthorhombic, space group P212121, and the unit cell contains
four molecules which therefore occupy general positions in the
lattice. The structure is illustrated in Figure 2. As expected,
the phenyl groups are roughly perpendicular to the mean plane
of the central naphthalene, with dihedral angles ranging from
68° to 89°. The displacements of the peri phenyls above and
below the naphthalene are quite substantial, however, with ipso
carbons as much as 0.70 Å away from the naphthalene mean
plane. The naphthalene itself adopts an undulating conformation
composed of two shallow boats, with no carbon atom more than
0.14 Å from the mean plane of the ring system. This geometry
is very similar to the Ci symmetric naphthalenes observed in
the red form of octakis(phenylthio)naphthalene,8a the bis-
(dioxane) clathrate of octakis(p-tolylthio)naphthalene,8b and
octakis(cyclohexylthio)naphthalene,8c but in the present case a
small (3°) twist of the naphthalene is also present, reducing the
symmetry to C1.
Overall, then, octaphenylnaphthalene and decaphenylan-
thracene were prepared from tetracyclone in 26% and 0.1%
yields, respectively.
Prior to the determination of the X-ray structure, we had
examined the structures and energies of various conformations
of compound 2 by means of AM1 calculations.12 Interestingly,
(9) Ried, W.; Bonnighausen, K. H. Liebigs Ann. Chem. 1961, 639, 61-
67.
(10) Beringer, F. M.; Huang, S. J. J. Org. Chem. 1964, 29, 445-448.
(11) Hart, H.; Nwokogu, G. J. Org. Chem. 1981, 46, 1251-1255.
(12) Dewar, M. J. S.; Zoebisch, E. G.; Healy, E. F.; Stewart, J. J. P. J.
Am. Chem. Soc. 1985, 107, 3902-3909.

Octaphenylnaphthalene and Decaphenylanthracene
J. Am. Chem. Soc., Vol. 118, No. 4, 1996 743
a twisted geometry (naphthalene end-to-end twist ) 31°), fully
optimized under the constraint of C2 symmetry, was found to
be 2.6 kcal/mol lower in energy than a fully optimized Ci
conformation. With the solution of the crystal structure, the
X-ray coordinates were entered as the intitial geometry in an
unconstrained AM1 optimization. This ultimately yielded a C1
structure similar to the previously calculated Ci geometry with
an energy still 2.6 kcal/mol above the apparent C2 ground state
(frequency calculations indicated that both the C1 and C2
geometries are true potential minima). This is a very small
energy difference for so large a molecule, but the calculation
may be inaccurate, or, alternatively, the observed C1 structure
may be imposed by crystal packing forces. In this regard, it is
noteworthy that octakis(phenylthio)naphthalene and octakis-
(p-tolylthio)naphthalene each exist in two crystal forms (either
polymorphs or different solvates) with both C2 and Ci symmetric
naphthalenes represented, suggesting that the two geometries
are very close in energy.8 We have not, however, observed a
second crystal form of compound 2.
Octaphenylnaphthalene contains 58 carbon atoms, but only
10 resonances are observed in its 13C NMR spectrum. For this
reason, whatever geometry is the ground state in solution, the
conformational flexibility of 2 is great enough to provide it with
time-averaged D2h symmetry, or D2 symmetry with rapid phenyl
rotation, on the NMR time scale.
Figure 3. Space-filling illustration of the crystal packing of decaphen-
ylanthracene. The view is down the crystallographic c axis in order to
show the solvent channels.
Structure of Decaphenylanthracene. Compound 3 crystal-
lized only as long, very thin needles from a wide variety of
solvents, and in all cases some solvent appeared to be present
in the crystals. The crystals from toluene were the largest, but
even so a diffractometer equipped with a rotating anode and an
image plate was required to collect a satisfactory X-ray data
set. The crystals are orthorhombic, space group Pccn; there
are four molecules in the unit cell, which lie on special positions
and possess crystallographic C2 symmetry. The molecular
structure of 3 is illustrated in Figure 2. Most significantly, the
anthracene core adopts a longitudinally twisted conformation
with an overall end-to-end twist of 62.8°; the three rings
contribute 18.8°, 25.2°, and 18.8°, respectively.13 The central
ring is thus more twisted than any of the rings in compound 8
or its derivatives, although the overall twist of 3 is slightly less
than 8.2b As in compound 2, the phenyl substituents of 3 are
rotated out of the mean planes of the anthracene rings to which
they are attached, but the large twist of the anthracene permits
the phenyl-acene dihedral angles to be less nearly perpendicular
(range, 58-79°) than in 2 (68-89°). The observed bond
distances in the anthracene are not unusual, and the greatest
deviations from “ideal” 120° bond angles are the opening of
the two symmetry independent C1-C9a-C9 angles (between the
peri substituents) to 125.3° and 124.3°, which is inevitable with
so large a twist. Since the overall molecular twist is achieved
by a series of small distortions from planarity, the p-orbitals on
adjacent carbons in the acene π-electron system are able to retain
good overlap.
The crystal packing for compound 3 is quite unusual. The
anthracenes are stacked “face-to-face” along the c axis, but there
are large solvent-containing channels running parallel to the
stacks (see Figure 3). The calculated volume of these channels
is approximately 1920 Å3, in principle sufficient for 14 toluenes
(volume ) 136 Å3) per unit cell, although the linear dimensions
of the channels are such that four to six toluene molecules might
be a more reasonable number. However, NMR analysis of the
crystals used for X-ray analysis indicated that there were only
two (toluene:3 ) 0.5), and whatever solvent is present is thor-
oughly disordered and invisible in the crystal structure. Mo-
lecular modeling studies suggested that long, thin organic mole-
cules might fit well in these channels, so we soaked some of
the yellow crystals of 3 for prolonged periods in a 0.2% metha-
nol solution of diphenyl-s-tetrazine, but no uptake of this brilliant
purple compound was observed as judged by optical microscopy.
Conclusion. Octaphenylnaphthalene is simply and efficiently
prepared in three steps from commercial starting materials.
Though highly crowded, the distortions of this naphthalene are
comparable to those of other octasubstituted naphthalenes. In
contrast, decaphenylanthracene is prepared only in very low
yield and the molecule is extremely distorted from planarity.
Does the π-electron system of 3 retain the characteristics of a
“normal” anthracene? Despite the 63° twist, the UV spectrum
of compound 3 (Figure 4) leaves no doubt: the E2 absorption
band has been shifted some 60 nm to the red (as should be
expected from the addition of eight aryl groups), but the
characteristic anthracene vibrational fine structure, though
unresolved, is still visible as shoulders on the 430 nm absorption
peak. Obviously, even greater molecular distortions would be
required to interfere with the conjugation of the acene. Since
the crystals (mp >400 °C) and solutions of decaphenylan-
thracene are quite robust, an even more highly twisted derivative
may well be stable under normal conditions, but the synthesis
of such a molecule is likely to be extremely difficult.
Although compound 3 adopts a chiral conformation with C2
symmetry, and approximate D2 symmetry, its 13C NMR
spectrum contains only 16 lines (for 74 carbons). As in the
case of compound 2, this clearly indicates that the conforma-
tional flexibility of 3 is great enough to yield time-averaged
D2h symmetry or D2 symmetry with rapid phenyl rotation on
the NMR time scale.
Experimental Section
(13) Our computational facilities are inadequate to perform AM1
calculations on a molecule as large as decaphenylanthracene. However, a
variety of conformations of 1,4,5,8,9,10-hexaphenyl-2,3,6,7-tetravinylan-
thracene were examined, the best of which was a twisted geometry some
7 kcal/mol lower in energy than any of the calculated Ci conformations.
3,4,5,6-Tetraphenylphthalimide (10). Tetraphenylcyclopentadi-
enone (9, 7.31 g, 19.0 mmol) and maleimide (1.80 g, 18.5 mmol) were
heated in refluxing nitrobenzene (30 mL) for 12 h. After cooling,

744 J. Am. Chem. Soc., Vol. 118, No. 4, 1996
Qiao et al.
then ethanol (3 mL) and 1% aqueous NaOH (9 mL) were added to
terminate it. Chloroform was added; the organic layer was separated,
washed with aqueous NaHCO3, dried over MgSO4, and concentrated
to dryness. The residue was subjected to silica gel column chroma-
tography (solvent, 7:5 hexanes-benzene), and the fractions containing
the desired product, which exhibited an Rf of 0.47 on TLC (silica gel
GF; solvent, 2:1 hexanes-benzene), were combined and concentrated
to give pure 2 as a white solid. Recrystallization from dichlo-
romethane-methanol gave crystals suitable for X-ray analysis (78 mg,
62%), mp 357-358 °C. 1H NMR (CDCl3) δ 6.60 (m, 30H), 6.72 (m,
10H); 13C NMR (CDCl3) δ 124.4, 124.7, 126.0, 131.1, 132.0, 133.1,
138.2, 140.0, 140.5, 142.0 (10 of 11 expected resonances observed;
but the δ 126.0 resonance may contain two lines); MS, m/z 736 (M+,
100), 659 (M - C6H5, 47), 582 (M - 2C6H5, 21); IR (KBr) νmax 3053,
3029, 1602, 1494, 1487, 1441 cm-1. Exact mass 736.3140, calcd for
C58H40 736.3130.
X-ray Crystallographic Analysis of Octaphenylnaphthalene (2).
A colorless prism of compound 2 measuring 0.12 mm × 0.22 mm ×
0.42 mm was used for X-ray studies. Crystal data: C58H40; ortho-
rhombic, space group P212121; a ) 13.469(1) Å, b ) 13.864(1) Å, c
) 22.043(2) Å, V ) 4116.2(5) Å3, Z ) 4, Dcalcd ) 1.189 g/cm3.
Intensity measurements were made with 3° e 2θ e 50° by using
graphite monochromated Mo KR radiation (λ ) 0.71073 Å) at 298 K
on a Siemens P4 diffractometer. A total of 8065 reflections were
measured, of which 7220 were unique (Rint ) 0.027). The structure
was solved by direct methods (SHELXTL-PLUS15) and refined by full-
matrix least-squares on F2 (SHELXL-9316). All non-hydrogen atoms
were refined with anisotropic displacement coefficients, and hydrogen
atoms were included with a riding model and isotropic displacements
coefficients [U(H) ) 1.2U(C)]. The refinements converged to R(F)
) 0.044, wR(F2) ) 0.079, and S ) 0.97 for 3872 reflections with F >
4σ(F), and R(F) ) 0.102, wR(F2) ) 0.093, and S ) 0.81 for 7220
unique reflections and 523 variables. Full details are given in the
supporting information.
5,8-Epoxy-5,8-dihydro-1,2,3,4,5,8-hexaphenylnaphthalene (12). A
solution of 2,5-diphenylfuran (133.6 mg, 0.681 mmol) in 1,2-dichlo-
roethane (25 mL) was heated to reflux. Isoamyl nitrite (0.10 mL) was
added, followed by the slow dropwise addition of a solution of
compound 11 (131.3 mg, 0.298 mmol) in dichloroethane (10 mL). The
solution was heated at reflux for 10 min, and then the reaction was
terminated by the addition of ethanol (5 mL) and 1% aqueous NaOH
(15 mL). Chloroform was added, and the organic layer was separated
and was washed with aqueous NaHCO3. After standing over MgSO4,
the organic extract was concentrated to dryness. A portion of the
residue was chromatographed on a silica gel column (solvent, 1:1
chloroform-hexanes) to yield the adduct 12, which displayed a single
component by TLC (Rf 0.64; silica gel GF; solvent, toluene). 1H NMR
(CDCl3) δ 6.53 (m, 6H), 6.73 (m, 14H), 7.01 (m, 6H), 7.29 (m, 4H),
7.61 (s, 2H); 13C NMR (CDCl3) δ 94.2, 125.2, 125.3, 125.6, 126.3,
126.4, 126.6, 127.2, 127.5, 127.6, 128.2, 129.0, 129.9, 130.5, 131.1,
131.4, 134.9, 135.9, 137.5, 138.7, 139.8, 144.9, 149.0 (23 of 23 expected
resonances observed); MS, m/z 600 (M+, 100), 495 (25), 417 (19),
159 (23), 105 (80). Exact mass 600.2460, calcd for C46H32O 600.2453.
Crystals of the chloroform solvate of 12, suitable for X-ray analysis,
were obtained by the slow evaporation of a solution of 12 in chloroform
and ethanol.
Figure 4. UV spectra (solvent, CHCl3) of solutions (approximately
1.1 × 10-4 M) of decaphenylanthracene (solid line) and anthracene
(dashed line).
methanol (400 mL) and water (70 mL) were added to precipitate crude
compound 10 (7.46 g), which was recrystallized from chloroform-
methanol and dried under vacuum to give pure 10 as colorless needles
(5.80 g, 69%), mp 324-325 °C (lit.14 mp 332-334 °C). 1H NMR
(CDCl3) δ 6.75 (m, 4H), 6.89 (m, 6H), 7.12 (m, 4H), 7.21 (m, 6H),
7.61 (br s, 1H); 13C NMR (CDCl3) δ 126.3, 127.0, 127.3, 127.4, 128.6,
129.8, 130.7, 135.4, 137.9, 139.7, 148.1, 166.7 (12 of 12 expected
resonances observed); MS, m/z 451 (M+, 100), 407 (16), 376 (21),
302 (15); IR (KBr) νmax 3217 (br, NH), 3078, 3049, 3020, 1771, 1715,
1357 cm-1
.
3,4,5,6-Tetraphenylanthranilic Acid (11). The phthalimide 10
(2.01 g, 4.45 mmol) was mixed with methanol (250 mL), and a solution
of NaOH (1.00 g, 25 mmol) in water (2 mL) was added, followed by
Chlorox (10 mL, 7.0 mmol of NaOCl). The mixture was brought
rapidly to a boil over an open flame, and it was heated at reflux for 10
min. After cooling, the reaction mixture was concentrated to half
volume and poured into dilute HCl (300 mL). This mixture was
extracted three times with chloroform, and the combined organic layers
were dried over MgSO4 and concentrated to dryness. Propanol (100
mL) and KOH (7.0 g) were added to the residue, and the mixture was
heated at reflux for 45 h. The contents of the reaction were poured
into water (300 mL), and the pH was adjusted to between 5 and 6. The
resulting mixture, which contained a fine, pale yellow precipitate, was
extracted twice with chloroform, and the combined organic extracts
were dried over Na2SO4 and concentrated to dryness. The residue was
recrystallized from chloroform-ethanol to yield pale yellow compound
11 (1.20 g, 61%), mp 275-278 °C dec. 1H NMR (DMSO-d6) δ 6.70-
6.85 (m, 10H), 7.00-7.25 (m, 10H); 13C NMR (DMSO-d6) δ 118.3,
125.0, 125.4, 126.0, 126.4, 126.5, 126.8, 126.9, 128.3, 129.78, 129.81,
130.4, 130.6, 131.5, 137.1, 139.1, 139.6, 139.9, 140.4, 142.0, 142.5,
170.1 (22 of 23 expected resonances observed); MS, m/z 441 (M+,
100), 423 (M - H2O, 23), 422 (M - H2O - H, 37), 397 (M - CO2,
65), 394 (47), 318 (28), 317 (29); IR (KBr) νmax 3504 (NH), 3384 (NH),
3056, 3025, 2300-3200 (br, COOH), 1650, 1582, 1579, 1420, 1240
cm-1. Exact mass 441.1723, calcd for C31H23NO2 441.1729.
X-ray Crystallographic Analysis of Compound 12. A crystal of
12‚CHCl3 measuring 0.05 mm x 0.38 mm × 0.55 mm was used for
X-ray measurements. Crystal data: C46H32O‚CHCl3; monoclinic, space
group P21/n; a ) 15.454(4) Å, b ) 11.549(3) Å, c ) 21.362(5) Å, â
) 92.333(14)°, V ) 3809(2) Å3, Z ) 4, Dcalcd ) 1.256 g/cm3. Intensity
measurements were made with 3° e 2θ e 45° by using graphite
monochromated Mo KR radiation (λ ) 0.71073 Å) at 296 K on a
Siemens P4 diffractometer. A total of 5203 reflections were measured,
of which 4985 were unique (Rint ) 0.055). The structure was solved
by direct methods (SHELXTL-PLUS15) and refined by full-matrix least-
squares on F2 (SHELXL-9316). All non-hydrogen atoms were refined
with anisotropic displacement coefficients, and hydrogen atoms were
Octaphenylnaphthalene (2). A solution of tetraphenylcyclopen-
tadienone (105 mg, 0.27 mmol) in 1,2-dichloroethane (5 mL) was heated
to gentle reflux under an argon atmosphere. A solution of isoamyl
nitrite (0.06 mL) in dichloroethane (6 mL) was added, followed by the
slow addition of compound 11 (74.8 mg, 0.170 mmol) in dichloroethane
(6 mL) over 25 min. The reaction was maintained at reflux for 1 h;
(15) Sheldrick, G. M. SHELXTL-PLUS, Release 4.21. Siemens Analytical
X-ray Instruments, Madison, Wisconsin, 1990.
(14) Harris, F. W.; Norris, S. O. J. Heterocycl. Chem. 1972, 9, 1251-
1253.
(16) Sheldrick, G. M. SHELXL-93. Program for the Refinement of Crystal
Structures. University of Gottingen, 1993.

Octaphenylnaphthalene and Decaphenylanthracene
J. Am. Chem. Soc., Vol. 118, No. 4, 1996 745
included with a riding model and isotropic displacement coefficients
[U(H) ) 1.2U(C)]. The refinements converged to R(F) ) 0.075,
wR(F2) ) 0.179, and S ) 1.36 for 992 reflections with F > 4σ(F),
and R(F) ) 0.294, wR(F2) ) 0.289, and S ) 0.71 for 4984 unique
reflections, 460 variables, and one distance restraint (on the C(1S)-
Cl(1S) bond). Full details are given in the supporting information.
Hexaphenylisobenzofuran (13), mp 252-253 °C (lit.9 mp 254-
257 °C), was prepared by the method of Ried and Bonnighausen.9 They
provided no spectroscopic data, so it is included here. 1H NMR (CDCl3)
δ 6.77-7.07 (m); 13C NMR (CDCl3) δ 121.1, 125.2, 126.2, 126.5,
127.1, 128.7, 131.0, 131.4, 131.5, 131.6, 138.0, 138.6, 140.1, 146.5
(14 of 16 expected resonances observed; but the δ 127.1 resonance
may contain 2 or 3 lines); FAB MS, m/z 575 (M + H, 100); IR (KBr)
X-ray Crystallographic Analysis of Decaphenylanthracene (3).
A yellow needle of 3‚0.5C7H8 measuring 0.02 mm × 0.04 mm × 0.88
mm was used for X-ray measurements. Crystal data: C74H50‚0.5C7H8;
orthorhombic, space group Pccn; a ) 19.811(21) Å, b ) 23.243(12)
Å, c ) 14.472(8) Å, V ) 6664(9) Å3, Z ) 4, Dcalcd ) 0.982 g/cm3.
Intensity data were collected out to 2θ ) 90° by using Cu KR radiation
(λ ) 1.54184 Å) at 298 K on a Rigaku R-AXIS IIC image plate system
equipped with a rotating anode and double-focusing mirrors. Forty
frames of data were collected with 5° of oscillation per frame. The
9426 observed reflections were indexed, integrated, and corrected for
Lorentz and polarization effects (using the program DENZO17), and
then the reflections were scaled and merged (SCALEPACK17 ). The
final data set contained 2242 unique reflections (Rint ) 0.029). The
structure was solved by direct methods (SHELXTL-PLUS15) and refined
by full-matrix least-squares on F2 (SHELXL-9316) to R(F) ) 0.152
with all carbons anisotropic and inclusion of hydrogen atoms with a
riding model [U(H) ) 1.2U(C)]. A difference-Fourier synthesis at this
stage revealed no peaks larger than 0.76 eÅ-3 in the two symmetry
related channels running parallel to the c axis. Attempts to fit the
electron density within the channels with discrete solvent molecules
were without success, so the SQUEEZE/BYPASS18 procedure imple-
mented in PLATON-9419 was used to account for the solvent electron
density. A total electron count of 92.6 e in a total volume of 1920 Å3
was found for the two channels, consistent with approximately one
toluene (50 e) per channel, which is in turn consistent with the 2:1
C74H50:C7H8 ratio observed by 1H NMR analysis of the batch of crystals
used for the X-ray studies. The SQUEEZE-processed data were used
for all subsequent cycles of refinement, which converged to R(F) )
0.070, wR(F2) ) 0.205, and S ) 1.17 for 1840 reflections with F >
4σ(F), and R(F) ) 0.078, wR(F2) ) 0.217, and S ) 1.10 for 2242
unique reflections and 335 variables. Full details are given in the
supporting information.
νmax 3050, 3024, 1598, 1494, 1442 cm-1
.
9,10-Epoxy-9,10-dihydrodecaphenylanthracene (14). A solution
of hexaphenylisobenzofuran (174.7 mg, 0.304 mmol) in 1,2-dichloro-
ethane (6 mL) was heated to reflux. A solution of isoamyl nitrite (0.04
mL) in dichloroethane (4 mL) was added, followed by the slow addition
of compound 11 (53.7 mg, 0.122 mmol) in dichloroethane (4 mL).
The solution was heated at reflux for 10 min, and then the reaction
was terminated by the addition of ethanol (2 mL) and 1% aqueous
NaOH (6 mL). Chloroform was added; the organic layer was separated,
washed with aqueous NaHCO3, dried over MgSO4, and concentrated
to dryness. The residue was subjected to preparative TLC (silica gel
GF; solvent, 1:1 hexanes-benzene). Elution of a band of Rf 0.50 gave
pure compound 14 (9 mg, 8%); mp 384-386 °C. Larger scale reactions
gave yields of 5% or less. 1H NMR (CDCl3) δ 6.33 (d, J ) 8 Hz,
4H), 6.47 (m, 8H), 6.55 (t, J ) 8 Hz, 8H), 6.66 (m, 8H), 6.78 (m,
10H), 6.92 (t, J ) 8 Hz, 4H), 7.06 (t, J ) 8 Hz, 4H), 7.23 (d, J ) 8
Hz, 4H); 13C NMR (CDCl3) δ 91.8, 124.9, 125.4, 125.7, 126.1, 126.2,
126.6, 127.3, 129.2, 130.8, 131.1, 132.0, 134.5, 135.2, 139.1, 140.3,
140.5, 147.4 (18 resonances observed; 16 are expected if there is free
rotation at all phenyls, 22 if rotation is fully restricted); FAB MS, m/z
956 (M + 2H, 100), 955 (M + H, 42); IR (KBr) νmax 3055, 3025,
1601, 1494, 1442 cm-1
.
Acknowledgment. This work was supported by National
Science Foundation Grant No. CHE-9408295 (to R.A.P.) and
National Institutes of Health Grant No. AI30743 (to C.E.S.).
Decaphenylanthracene (3). The oxide 14 (150 mg, 0.157 mmol)
was heated to reflux in acetic acid (10 mL). An excess of activated
Zn dust (0.24 g) was added in a single portion, and heating was
continued for 9 h. The hot mixture was filtered through a fritted funnel,
which was rinsed with a small amount of hot acetic acid, and after
cooling water was added to the filtrate. The resulting greenish-yellow
precipitate was collected and dried under vacuum overnight. It was
then subjected to preparative TLC (silica gel GF; solvent, 17:10
hexanes-benzene). Elution of a bright yellow band of Rf 0.43 gave
pure compound 3 (4.5 mg, 3%); mp >400 °C. 1H NMR (CDCl3) δ
6.27 (d, J ) 8 Hz, 8H), 6.42 (t, J ) 8 Hz, 4H), 6.53 (m, 20H), 6.74
(m, 18H); 13C NMR (CDCl3) δ 124.1, 124.8, 125.4, 125.9, 126.1, 126.4,
131.1, 131.8, 132.3, 134.8, 135.9, 136.9, 138.5, 140.4, 140.9, 142.0
(16 of 16 expected resonances observed); FAB MS, m/z 939 (M + H,
100); IR (KBr) νmax 3056, 3020, 1601, 1491, 1441 cm-1. UV (CDCl3)
Supporting Information Available: X-ray crystal structure
report for octaphenylnaphthalene (2), decaphenylanthracene (3),
and 12 (54 pages). This material is contained in many libraries
on microfiche, immediately follows this article in the microfilm
version of the journal, can be ordered from the ACS, and can
be downloaded from the Internet; see any current masthead page
for ordering information and Internet access instructions.
JA953669S
(17) Minor, W. XDISPLAYF Program. Purdue University, 1993.
(18) Van der Sluis, P.; Spek, A. L. Acta Crystallogr., Sect. A 1990, 46,
194-201.
λmax (log ꢀ) 323 nm (4.8), 408 (sh, 3.9), 430 (4.0), 452 (sh, 3.9). Long
needles of the toluene solvate of 3, suitable for X-ray analysis, were
obtained by the slow evaporation of a toluene solution of 3.
(19) Spek, A. L. Acta Crystallogr., Sect. A 1990, 46, C34.