Crystal structure of 3,4,5,6-tetrahydrophthalic anhydride at 150 K

Article abstract of DOI:10.1002/hlca.200490140

The crystal structure of 3,4,5,6-tetrahydrophthalic anhydride, (=4,5,6,7-tetrahydroisobenzofuran-1,3-dione; 1; C₈H₈O ₃) was determined and refined by an analysis of three-dimensional X-ray-diffraction data at 150 K. This bicyclic compound crystallizes in space group Pbca with two symmetry-independent molecules I and II per asymmetric unit. The cyclohexene ring in both molecules adopts a half-chair conformation. The obtained conformational descriptions of the six-membered rings in the crystal phase are consistent with conformational data derived from molecular-orbital calculations. The structure analysis evidences considerable distorsion of the partially hydrogenated six-membered ring; the furan ring is flattened in molecule I and slightly deviated from planarity in molecule II. The short intermolecular distances found for C=O ... C=O are interpreted as evidence for nonbonded interactions of the dipole - dipole type. The rather long O ... H distances indicate that the C(sp³)-H ... O interactions are weak.

Full text of DOI:10.1002/hlca.200490140

Helvetica Chimica Acta ± Vol. 87 (2004)
1527
Crystal Structure of 3,4,5,6-Tetrahydrophthalic Anhydride at 150 K
a
b
a
a
by Arij Ben Fredj* ), Muriel Bagieu-Beucher ), Sadok Ben Rejeb ), and Zohra Ben Lakhdar )
a) Laboratoire de Spectroscopie Atomique, Mol e¬ culaire et Applications, Facult e¬ des Sciences de Tunis, Campus
Universitaire 1060, Tunis, Tunisie (fax: ‡21671 88 50 73, e-mail: erijbf@yahoo.fr)
b) Laboratoire de Cristallographie associ e¬ a¡ l×Universit e¬ Joseph Fourier, CNRS, BP 166,
F-38042 Grenoble Cedex 09
The crystal structure of 3,4,5,6-tetrahydrophthalic anhydride, (ˆ4,5,6,7-tetrahydroisobenzofuran-1,3-
8 8 3
dione; 1; C H O ) was determined and refined by an analysis of three-dimensional X-ray-diffraction data at
1
50 K. This bicyclic compound crystallizes in space group Pbca with two symmetry-independent molecules I and
II per asymmetric unit. The cyclohexene ring in both molecules adopts a half-chair conformation. The obtained
conformational descriptions of the six-membered rings in the crystal phase are consistent with conformational
data derived from molecular-orbital calculations. The structure analysis evidences considerable distorsion of the
partially hydrogenated six-membered ring; the furan ring is flattened in molecule I and slightly deviated from
planarity in molecule II. The short intermolecular distances found for CˆO ¥¥¥ CˆO are interpreted as evidence
3
for nonbonded interactions of the dipole ± dipole type. The rather long O ¥¥¥ H distances indicate that the C(sp )-
H ¥¥¥ O interactions are weak.
Introduction. ± Within the context of studies on the conformations of bicyclic
anhydrides, the structure of cis-1,2,3,6-tetrahydrophthalic anhydride C H O has been
8
8
3
determined by X-ray diffraction [1]; its crystal structure consists of two symmetry-
independent molecules per asymmetric unit. Their conformations are folded, both
possessing a boat form for the cyclohexene ring, in agreement with experimental NMR
solution data [2][3]. Crystal packing of the two independent molecules in the unit cell
has also been investigated [4], establishing non-bonded interactions of the dipoleÀdi-
pole type between local electrical dipoles of the carbonyl groups CˆO ¥¥¥ CˆO.
Concomitantly, several techniques of semi-empirical and ab initio molecular-orbital
calculations have been applied for the determination of the molecular geometry of this
compound and its isomers, 3,4,5,6-, 1,2,5,7-, and 1,4,5,6-tetrahydrophthalic anhydrides
[
1
5]. These calculations confirmed the preference of the folded conformation for cis-
,2,3,6-tetrahydrophthalic anhydride and revealed large differences in the stereo-
chemical behavior of these isomeric tetrahydrophthalic anhydrides. In view of the
considerable interest in the structural properties of this series of anhydride isomers, it
appeared desirable to have precise structural data for a selected compound to provide a
check of the theory and possibly to aid in formulating refinements in the calculations.
Experimental structures of the gas-phase molecules have not yet been reported, and,
besides two crystallographic studies on derivatives of 3,4,5,6-tetrahydrophthalic
anhydride [6][7], no experimental data on the parent compound are available. Thus,
in the present work, an investigation of the crystal structure of 3,4,5,6-tetrahydroph-
thalic anhydride (ˆ4,5,6,7-tetrahydroisobenzofuran-1,3-dione; 1) was undertaken to
reveal the most stable conformation and to elucidate the structural differences between

1
528
Helvetica Chimica Acta ± Vol. 87 (2004)
the 3,4,5,6-tetrahydrophthalic and cis-1,2,3,6-tetrahydrophthalic isomers. Because the
tetrahedral C-atoms exhibit unusually large anisotropic displacement parameters
without apparent statistical disorder and interatomic distances shorter than the normal
CÀC bonds at room temperature [8], a low-temperature structure determination was
performed. The results of such an analysis for a single crystal of 1 at 150 K led to an
improved agreement of the crystal-structure model and the experimental data of the
related compounds.
Results and Discussion. ± The asymmetric unit of the single crystal of 1 contains two
symmetry-independent molecules I and II as has been shown for the crystal of the cis-
1,2,3,6-tetrahydrophthalic isomer [1]. The structures of the two independent molecules
are very similar (Fig. 1). As implied by the semiquantitative rules of Bucourt for
conformational analysis [9][10], the cyclohexene ring is assumed to exist in a distorted
half-chair form in the two independent molecules. This typical conformation of the six-
membered ring observed for 1 has also been established to be the preferred one by
geometry-optimized AM1, PM3, and MNDO semi-empirical methods and ab initio
calculations at both the RHF/PS-31G* and MP2/PS-31G* levels by using the gradient
method [5]. The present results obtained for the crystal phase of 1 add additional
support to the conformational data derived from IRC calculations by using the PM3
semi-empirical method, which indicate the presence of two conformational minima for
1
(Fig. 2,a), both possessing a half-chair conformation for the cyclohexene ring
(
Fig. 2,b). This significant difference from the conformational preference of the
cyclohexene ring in the crystal of the cis-1,2,3,6-tetrahydrophthalic isomer was
expected. The dissimilarities may be attributed mainly to the difference in the position
of the CˆC bond in the bicyclic system. The degree of freedom between the bonds in
the cyclohexene ring is more restricted in cis-1,2,3,6-tetrahydrophthalic anhydride
owing to the cis orientation of the furan ring with respect to the cyclohexene ring [11].
A comparison of structural parameters between the two independent molecules I
and II shows internal consistency. The most-prominent discrepancies are displayed
among the parameters determining the geometry of the cyclohexene ring, which shows
significant deviations from a C symmetric internal top. The ring dihedral angles at the
2
bonds C(7)ÀC(6), C(6)ÀC(5), and C(4)ÀC(5) in molecule I (absolute values 16.8(3),
4
6.2(2), and 61.5(2)8, resp.) are larger than the corresponding angles in molecule II
1
(
absolute values 13.1(3), 42.9(2), and 61.3(2)8, resp.) (Table 1) ). For the C(2)ÀC(3)
and C(3)ÀC(4) bonds, the absolute values of the dihedral angles of I (11.6(3) and
1.1(2)8, resp.) are both lower than those observed in II (14.5(3) and 44.1(2)8, resp.).
All the dihedrals indicated above deviate significantly from the values of unfused
4
2
3
cyclohexene rings [12] (absolute values 15.2, 44.9, and 60.28 at the bonds C(sp ) ± C(sp )
1)
Arbitrary numbering, according to Fig. 1.

Helvetica Chimica Acta ± Vol. 87 (2004)
1529
1
Fig. 1. ORTEP View of the molecules I and II in the asymmetric unit,showing the labelling of the non-H-atoms ).
Ellipsoids are drawn at the 50% probability level.
3
3
3
3
(
CˆC), C(sp ) ± C(sp ) (CˆC), and C(sp ) ± C(sp ), resp.), which adopt an ideal half-
chair conformation. We may assume that deviations from these values are an index of
strain with respect to the undistorted cyclohexene derivatives, and that the differences
represent the angular deformations from the ideal half-chair conformations. Also, in
both independent molecules I and II, the torsional angles deviate significantly from the
corresponding values calculated for the two conformers of 1 at the MP2/PS-31G* level
2
3
3
[
5] (absolute values 14.6, 44.3, and 63.08 at the bonds C(sp ) ± C(sp ) (CˆC), C(sp ) ±
3 3 3
C(sp ) (CˆC), and C(sp ) ± C(sp ), resp.). The distortion of the cyclohexene ring in 1,
owing to the fusion with the furan ring, could not be detected theoretically at the ab
initio MP2 level as well as at different levels of semiempirical molecular-orbital
calculations [5]. This indicates that the distortion of the cyclohexene rings detected in
the crystal phase is undoubtly due to crystal-packing forces and, as will be discussed
later, the differences in the changes in the chemically equivalent parts of the
cyclohexene rings are nevertheless consistent with packing effects. As far as the valence
angles are concerned, very slight differences are found in some intra-cyclohexene ring
angles such as C(3)ÀC(2)ÀC(7) and its chemical equivalent C(2)ÀC(7)ÀC(6), which
deviate by 0.6(2) and 0.5(2)8, respectively, in molecule II compared to molecule I.
These differences are obviously due to packing effects since there is no chemical
difference between the two molecules. The angles within the furan ring in both
molecules are normal compared to those observed in maleic anhydride [13] and some
of its derivatives [6][7], which exhibit similar deviations from the data of succinic

1
530
Helvetica Chimica Acta ± Vol. 87 (2004)
Fig. 2. a) Energy profile of 3,4,5,6-tetrahydrophthalic anhydride (1) obtained from IRC by the PM3
semiempirical method. b) Calculated ground-state conformations I and II of 1 and the structure of the transition
state (TS).
anhydride [14] and cis-1,2,3,6-tetrahydrophthalic anhydride [1]. The geometry of the
furan ring in molecule I is planar or nearly so: all of the ring dihedral angles are less
than or equal to 0.2(2)8 in absolute values. In molecule II, however, the ring dihedrals
are in the range 0.9(2) ± 2.9(2)8 with absolute values of 2.3(2), 2.9(2), and 2.4(3)8 at the
bonds C(10)ÀC(9), O(4)ÀC(9), and C(16)ÀO(4), respectively. Accordingly it seems
appropriate to describe the geometry of molecule II as slightly nonplanar, being
puckered at the O(4) atom. The CÀO and CˆO bond lengths as well as the CÀC bond
length in the furan ring of the two independent molecules agree well with those found
in maleic anhydride [13] and its derivatives [6][7]. The CˆC bond distance (1.331(2) ä
in I and 1.332(2) ä in II) is in good agreement with those observed in 3,4,5,6-

Helvetica Chimica Acta ± Vol. 87 (2004)
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1
Table 1. Selected Geometric Parameters for 3,4,5,6-Tetrahydrophthalic Anhydride (1) ). Esd. are given in
parentheses.
Molecule I
Molecule II
Bond lengths [ä]: O(1)ÀC(8)
O(1)ÀC(1)
1.396(2)
1.401(2)
1.193(2)
1.192(2)
1.472(2)
1.331(3)
1.474(3)
1.487(3)
1.526(3)
1.527(3)
1.528(3)
1.487(3)
Bond lengths [ä]: O(4)ÀC(9)
O(4)ÀC(16)
1.399(2)
1.396(2)
1.193(2)
1.193(2)
1.474(3)
1.332(3)
1.480(3)
1.487(3)
1.528(3)
1.531(3)
1.530(3)
1.490(3)
O(2)ÀC(1)
O(5)ÀC(9)
O(3)ÀC(8)
O(6)ÀC(16)
C(1)ÀC(2)
C(16)ÀC(15)
C(2)ÀC(7)
C(15)ÀC(10)
C(7)ÀC(8)
C(9)ÀC(10)
C(2)ÀC(3)
C(14)ÀC(15)
C(3)ÀC(4)
C(13)ÀC(14)
C(4)ÀC(5)
C(12)ÀC(13)
C(5)ÀC(6)
C(11)ÀC(12)
C(6)ÀC(7)
C(10)ÀC(11)
Valence angles [8]:
C(1)ÀO(1)ÀC(8)
C(8)ÀC(7)ÀC(2)
O(2)ÀC(1)ÀO(1)
C(7)ÀC(6)ÀC(5)
C(6)ÀC(5)ÀC(4)
C(4)ÀC(3)ÀC(2)
C(3)ÀC(2)ÀC(7)
C(2)ÀC(7)ÀC(6)
Dihedral angles [8]:
O(1)ÀC(8)ÀC(7)ÀC(2)
C(8)ÀC(7)ÀC(2)ÀC(1)
O(1)ÀC(1)ÀC(2)ÀC(7)
C(2)ÀC(1)ÀO(1)ÀC(8)
C(3)ÀC(2)ÀC(7)ÀC(6)
C(2)ÀC(7)ÀC(6)ÀC(5)
C(3)ÀC(4)ÀC(5)ÀC(6)
C(2)ÀC(3)ÀC(4)ÀC(5)
C(4)ÀC(3)ÀC(2)ÀC(7)
C(4)ÀC(5)ÀC(6)ÀC(7)
C(1)ÀO(1)ÀC(8)ÀC(7)
Valence angles [8]:
107.5(1)
C(9)ÀO(4)ÀC(16)
C(9)ÀC(10)ÀC(15)
O(6)ÀC(16)ÀO(4)
C(10)ÀC(11)ÀC(12)
C(11)ÀC(12)ÀC(13)
C(13)ÀC(14)ÀC(15)
C(14)ÀC(15)ÀC(10)
C(11)ÀC(10)ÀC(15)
Dihedral angles [8]:
O(4)ÀC(9)ÀC(10)ÀC(15)
C(9)ÀC(10)ÀC(15)ÀC(16)
O(4)ÀC(16)ÀC(15)ÀC(10)
C(9)ÀO(4)ÀC(16)ÀC(15)
C(11)ÀC(10)ÀC(15)ÀC(14)
C(12)ÀC(11)ÀC(10)ÀC(15)
C(11)ÀC(12)ÀC(13)ÀC(14)
C(12)ÀC(13)ÀC(14)ÀC(15)
C(10)ÀC(15)ÀC(14)ÀC(13)
C(10)ÀC(11)ÀC(12)ÀC(13)
C(10)ÀC(9)ÀO(4)ÀC(16)
107.6(1)
108.5(2)
120.3(2)
108.8(2)
112.1(2)
109.8(2)
125.4(2)
124.9(2)
108.0(2)
121.0(2)
109.3(2)
112.3(2)
109.6(2)
124.8(2)
125.4(2)
À 0.2(2)
0.2(2)
À 2.3(2)
0.9(2)
0.9(2)
À 0.1(2)
À 0.1(2)
À 0.6(3)
À 16.8(3)
À 61.5(2)
41.1(2)
À 2.4(2)
1.2(3)
13.1(3)
61.3(2)
À 44.1(2)
14.5(3)
À 42.9(2)
2.9(2)
À 11.6(3)
46.2(2)
0.2(2)
tetrahydrophthalimide [15] and 8,9,10-trinorborn-2-ene-2,3-dicarboxylic anhydride-
C H O [6] (1.324(5) and 1.332(4) ä, resp.), which possess a similar furan-ring moiety.
9
8
3
One of the most interesting features is the crystal packing of 1 (Fig. 3). The packing
pattern reveals a large number of close intermolecular contacts among the electrophilic
C-atoms (El) and their concomitant nucleophilic O-atoms (Nu) of symmetry-related
molecules I and II as well as between the H- and the O-atoms of symmetry-
independent molecules I and II that are within the range of the Van der Waals
interactions. The significant intermolecular NuÀEl CˆO ¥¥¥ CˆO bonds that are within
the presently acceptable limit (d(O ¥¥¥ C) ꢀ 3.4 ä) [16], the noncovalent angles q
(O ¥¥¥ CO), and the dihedral angles f (O ¥¥¥ COC) (CO being a carbonyl group)
defining the NuÀEl O ¥¥¥ C atom abstraction distance are reported in Table 2. The
minimum intermolecular CˆO ¥¥¥ CˆO distance is 2.957(2) ä between molecules I and
2.926(2) ä between molecules II (Fig. 4). The latter short contacts are significantly
smaller than the sum of the Van der Waals radii, which is assumed to be 3.2 ä [17]. All

1
532
Helvetica Chimica Acta ± Vol. 87 (2004)
Fig. 3. View of the structural arrangement of 1 down [0 1 0]. O-Atoms
black, C-atoms grey, and H-atoms white.
the distances indicated above and the other ones reported in Table 2 are within the
range of values observed for several contacts of the same type in the crystal structure
of cis-1,2,3,6-tetrahydrophthalic anhydride [1][4]. They are also in good agreement
with the corresponding values found by Cossu et al. [16] for a series of mono- and
polycyclic anhydride compounds that also exhibit solid-state intermolecular NuÀEl
CˆO ¥¥¥ CˆO interactions. The values of the noncovalent angles q (O ¥¥¥ CO) are in the
range 83.1(1) ± 89.5(1)8 with only two q values out of the bisector criteria (f ꢁ 908) [16].
If we exclude these uncertain interactions, we can state that the carbonyl groups are
involved in significant CˆO ¥¥¥ CˆO dipoleÀdipole interactions. In the two other cases
(
q ˆ 83.4(1) and 83.1(1)8), the nucleophilic O-atom is in close contact with the
electrophilic carbonyl group (O(5) ¥¥¥ C(16) distance of 3.195(2) ä and O(3) ¥¥¥ C(1)
distance of 3.191(2) ä; see Table 2), and both correspond to carbonyl groups forming
dimers held together by somewhat weaker NuÀEl dipoleÀdipole CˆO ¥¥¥ CˆO
interactions.
In addition to the Nu ± El CˆO ¥¥¥ CˆO interactions, the crystal packing of 3,4,5,6-
3
tetrahydrophthalic anhydride (1) is stabilized by weak C(sp )ÀH ¥¥¥ O intermolecular
interactions [18]. Geometric details of the H-bonds that are within the accepted range
(
d(O ¥¥¥ H) ꢀ 2.8 ä and q (CÀH ¥¥¥ O) > 1208) are given in Table 3. The most-significant
intermolecular H-bonds observed in this molecular packing are C(14)ÀH(15) ¥¥¥ O(5)
2.59(2) ä, 130(2)8) and C(11)ÀH(9) ¥¥¥ O(5) (2.66(2) ä, 161(2)8) between H-atoms of
(

Helvetica Chimica Acta ± Vol. 87 (2004)
1533
Fig. 4. Details of some interactions between molecules of 3,4,5,6-
tetrahydrophthalic anhydride (1). The figure evidences the shortest
contacts CˆO ¥¥¥ CˆO between molecules of the same type I or II and
the H-bonds interconnecting the molecules I and II.
Table 2. Geometric Parameters (d, q and f) of the Intermolecular CˆO ¥¥¥ CˆO Bonds
CˆO ¥¥¥ CˆO
Type
d(O ¥¥¥ C) [ä]
q (O ¥¥¥ CO)[8]
f (O ¥¥¥ COC)[8]
C(1)ˆO(2) ¥¥¥ C(8)ˆO(3)
C(1)ˆO(2) ¥¥¥ C(8)ˆO(3)
C(8)ˆO(3) ¥¥¥ C(1)ˆO(2)
C(8)ˆO(3) ¥¥¥ C(1)ˆO(2)
C(16)ˆO(6) ¥¥¥ C(9)ˆO(5)
C(9)ˆO(5) ¥¥¥ C(16)ˆO(6)
I ± I
I ± I
I ± I
I ± I
II ± II
II ± II
2.957(2)
3.109(2)
3.148(2)
3.191(2)
2.926(2)
3.195(2)
89.0(1)
87.2(1)
88.8(1)
83.4(1)
89.5(1)
83.1(1)
91.8
107.2
71.0
66.9
100.2
115.1
the six-membered ring and the carbonyl O-atom of molecules II. The shortest
3
intermolecular C(sp )ÀH ¥¥¥ O H-bonds observed between molecules I are C(3)À
H(1) ¥¥¥ O(3) (2.71(2) ä, 129(2)8) and C(6)ÀH(7) ¥¥¥ O(1) (2.79(2) ä, 155(2)8) involv-
ing both the O(3) and O(1) atoms of the anhydride moiety. Further analysis shows that
symmetry-independent molecules I and II are arranged into infinite chains along the
c-axis through four weak H-bonds: C(13)ÀH(13) ¥¥¥ O(1) (2.67(2) ä, 141(2)8),
C(12)ÀH(12) ¥¥¥ O(3) (2.77(2) ä, 153(2)8), C(4)ÀH(3) ¥¥¥ O(6) (2.76(2) ä, 157(2)8),
and C(5)ÀH(6) ¥¥¥ O(5) (2.80(2) ä, 132(2)8) (Fig. 4). These chains are connected in
the lateral directions by more-significant interactions between symmetry-dependent
molecules (type I ± I or II ± II), as specified in Table 2 for the CˆO ¥¥¥ CˆO interactions
and in Table 3 for the CÀH ¥¥¥ O H-bonds.
Clearly, the strong acceptor ability of the carbonyl O-atoms dominates the packing
of 3,4,5,6-tetrahydrophthalic anhydride (1) and its isomer cis-1,2,3,6-tetrahydro-
phthalic anhydride [1][4]. Both structures contain CˆO ¥¥¥ CˆO and CÀH ¥¥¥ O

1
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Helvetica Chimica Acta ± Vol. 87 (2004)
3
Table 3. Geometric Parameters (d and q) of the Intermolecular C(sp )ÀH ¥¥¥ O Hydrogen Bonds
CÀH ¥¥¥ O
Molecules
d(H ¥¥¥ O) [ä]
q(CÀH ¥¥¥ O)[8]
C(3)ÀH(1) ¥¥¥ O(3)
C(4)ÀH(3) ¥¥¥ O(6)
C(5)ÀH(6) ¥¥¥ O(5)
C(6)ÀH(7) ¥¥¥ O(1)
C(11)ÀH(9) ¥¥¥ O(5)
C(11)ÀH(10) ¥¥¥ O(6)
C(12)ÀH(12) ¥¥¥ O(3)
C(13)ÀH(13) ¥¥¥ O(1)
C(14)ÀH(15) ¥¥¥ O(5)
I ± I
2.71(2)
2.76(2)
2.80(2)
2.79(2)
2.66(2)
2.76(2)
2.77(2)
2.67(2)
2.59(2)
129(2)
157(2)
132(2)
155(2)
161(2)
127(2)
153(2)
141(2)
130(2)
I ± II
I ± II
I ± I
II ± II
II ± II
II ± I
II ± I
II ± II
Table 4. Crystal Data,Experimental Conditions,and Details of Structure Refinement
Empirical formula
Formula weight [g ¥ mol
Temperature [K]
Crystal system
Space group
Unit-cell dimensions:
a [ä]
8 8 3
C H O
152.15
150
Orthorhombic
Pbca
À1
]
9.7936(2)
9.0338(1)
31.7069(6)
90
2805.22(7)
16
b [ä]
c [ä]
a ˆ b ˆ g [8]
3
V [ä ]
Z
À3
Calc. density D
x
[Mg ¥ m
]
1.441
Crystal size [mm]
0.68 Â 0.34 Â 0.31
Radiation, wavelength [ä]
Absorption coefficient m [mm
Measurement method
Bragg-angle limits [8]
Limiting indices
Measured reflections
Independent reflections
Observed reflections
Number of variables
Final agreement factors
Goodness-of-fit on F
a
AgK , 0.5608
À1
]
0.068
f and w scans
3.0 ± 20.0
À 11 ! 11, À10 ! 10, À38 ! 29
13803
2535
1882 with I > 2s (I)
264
R ˆ 0.038, wR ˆ 0.044
S ˆ 1.44
Largest peak and hole in the last
difference-Fourier synthesis [e ä
À3
]
0.24, À0.23
3
bonds, together with interactions involving the carbonyl O-atom and either C(sp )ÀH
2
or C(sp )ÀH (in cis-1,2,3,6-tetrahydrophthalic anhydride). As pointed out in our
structure analysis of cis-1,2,3,6-tetrahydrophthalic anhydride [1][4] and its derivatives
[
16], an obvious relationship between the postulated typical intermolecular interac-
tions and the packing modes of 1 can be predicted. The study of the efficiency of these
intermolecular interactions in inducing geometrical deformation of the structure of 1 is
undertaken and the results obtained will be reported in an independent work.

Helvetica Chimica Acta ± Vol. 87 (2004)
1535
Experimental Part
Synthesis. The 3,4,5,6-tetrahydrophthalic anhydride (1) was prepared by complete isomerization of a pure
sample of cis-1,2,3,6-tetrahydrophthalic anhydride (m.p. 376 K) at 473 K, with P as acid catalyst according to
Bailey and Amstutz [19]. Subsequent purification by recrystallization from anh. cyclohexane yielded pure 1.
2
O
5
1
13
M.p. 357 K, H-NMR (CDCl
CH
); 68.12 (s, CˆC); 87.86( s, 2 CˆO).
Colorless crystals were obtained by slow evaporation of a dilute soln. of pure samples of 1 in anh.
3
): 1.5 (m, 2 CH
2
), 2.5 (m, 2 CH
2
). C-NMR (CDCl
3
): À56.41 (s, 2 CH ); À56.27 (s,
2
2
2
cyclohexane at r.t. in a dry-box.
X-Ray Structure Determination. As the crystals were hygroscopic, the single crystal used was mounted in a
thin-walled glass capillary of the Lindemann type during data collection. The intensity data were collected at 150 K
on a Nonius four-circle diffractometer equipped with a CCD bidimensional detector and an Oxford Cryostream
crystal-cooling system. Crystal data, details of data collection, and structure refinement are summarized in Table 4.
Intensities were corrected for Lorentz and polarization effects. No absorption corrections were applied. The
structure was solved by direct methods with the SIR92 program [20] and refined by the full-matrix least-squares
method, based on F, by using the teXsan software [21]. The refinement was performed with anisotropic temperature
factors for all non-H-atoms. H-Atoms were refined isotropically. A correction for secondary extinction [22] was
À6
applied with a value of the extinction parameter equal to 1.0(2)¥10 . The pictures of the crystal structure are shown
in Figs. 1, 3, and 4. The ORTEPII program [23] was used to produce the asymmetric unit of the structure (Figs. 1),
while the Cerius2 software [24] was applied to represent the molecular arrangement (Figs. 3 and 4). Crystallo-
graphic data (excluding structure factors) have been deposited with the Cambridge Crystallographic Data Centre, as
deposition No. CCDC 223922, and can be obtained via http://www.ccdc.cam.ac.uk/conts/retrieving.html (or from
the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK; fax: ‡441223336033; e-mail: deposit@ccdc.cam.ac.uk).
REFERENCES
[
[
[
[
[
[
[
[
[
1] A. Ben Fredj, S. Ben Rejeb, F. Ben Amor, A. Driss, Acta Crystallogr.,Sect. C 1998, 54, 1710.
2] B. D. Nageswara Rao, J. D. Baldeschwieler, J. Mol. Spectrosc. 1963, 11, 440.
3] H. Werner, E. Kleinpeter, A. Zschunke, G. Mann, J. Org. Magn. Reson. 1973, 5, 179.
4] A. Ben Fredj, S. Ben Rejeb, J. Soc. Chim. Tunisie 1999, IV, 575.
5] A. Ben Fredj, S. Ben Rejeb, N. JaÔdane, Z. Ben Lakhdar, J. Mol. Struct. (Theochem). 2000, 219.
6] W. H. Watson, P. R. Kashyap, Acta Crystallogr.,Sect. C 1985, 41, 1226.
7] D. L. Evans, W. T. Robinson, Acta Crystallogr.,Sect. B 1977, 33, 2891.
8] A. Ben Fredj, M. Bagieu, S. Ben Rejeb, M. Rzaigui, unpublished results.
9] R. Bucourt, D. Hainaut, Bull. Soc. Chim. 1967, 4562.
[
[
[
[
[
[
[
10] R. Bucourt, Bull. Soc. Chim. 1964, 2080.
11] A. Ben Fredj, Th e¡ se de Doctorat en Chimie-Physique, Facult e¬ des Sciences de Tunis, Tunisie, 2000.
12] J. H. Chiang, S. H. Bauer, J. Am. Chem. Soc. 1969, 1898.
13] R. E. Marsh, E. Ubell, H. L. Wilcox, Acta Crystallogr. 1962, 15, 35.
14] M. Ehrenberg, Acta Crystallogr. 1965, 19, 698.
15] A. Kirfel, Acta Crystallogr., Sect. B 1975, 31, 2494.
16] M. Cossu, C. Bachmann, T. Y. N×Guessan, R. Viani, J. Lapasset, J.-P. Aycard, H. Bodot, J. Org. Chem. 1987,
52, 5313.
[
[
17] A. I. Kitalgorodsky, −Organic Chemical Crystallography×, New York, 1961.
18] G. R. Desiraju, T. Steiner, in −The Weak Hydrogen Bond in Structural Chemistry and Biology×, Oxford
University Press, Oxford, UK, 1999, p. 1.
[
[
19] M. E. Bailey, E. D. Amstutz, J. Am. Chem. Soc. 1956, 78, 3828.
20] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, −SIR92 ± A Program for Automatic Solution of
Crystal Structures by Direct Methods×, J. Appl. Crystallogr. 1993, 26, 343.
[
21] Molecular Structure Corporation, −TeXsan for Windows. Single Crystal Structure Analysis Software.
Version 1.06×, MSC, 9009 New Trails Drive, The Woodlands, TX 77381, USA, 1997 ± 2001.
22] W. H. Zachariasen, Acta Crystallogr. 1967, 23, 558.
[
[
[
23] C. K. Johnson, −ORTEPII. Report ORNL-5138×, Oak Ridge National Laboratory, Tennessee, USA, 1976.
24] −Cerius2 Software. Version 4.2 MatSci.×, Molecular Simulations Inc., 9685 Scranton Road, San Diego,
California, USA 92121-3752, 2000.
Received January 28,2004