528
J Chem Crystallogr (2007) 37:527–535
which has large steric factor, no reaction was observed
during the addition of 3-methyl-butan-2-one to alcohol 1.
We were interested in the self-assembled superstructure in
solid state of 9-phenyl-9H-xanthen-9-ol (1) and change
of supramolecular architect with variation of the side arm
of the xanthene derivatives 1a–1j.
starting compound 1. Critical investigation of the solid
state structure can help us to reveal the effect of variation
of alkyl and aryl appendage on the supramolecular
assembly/crystal engineering. Here we present a combined
structural study of the 10 xanthene derivatives 1a–1j along
with its starting compound 1. They form different solid
state structure of interconnected conventional and non-
conventional hydrogen bonds.
O
O
The ORTEP [21] diagram of 1 with atomic numbering
scheme is shown in Fig. 1. In the asymmetric unit two
molecules of 1 crystallizes in the opposite directions.
Compound 1 structure is refined in non-centrosymmetric
space group P1. We have tried to refine the structure of 1 in
centrosymmetric space group P-1. However, the refinement
does not behave properly. Phenyl ring is oriented in an
almost perpendicular direction with respect to the xanthene
ring systems. Oxygen atoms of alcohol groups participates
in the formation of dimeric unit via the formation of in-
termolecular strong O–HÁÁÁÁp hydrogen bonding network.
Each of these dimeric units are interconnected to the
neighboring dimeric units via the formation of C–HÁÁÁÁp
type of hydrogen bonding (Fig. 2). Combination of various
types of intermolecular hydrogen bonding network results
in the formation of 3D pillared staircase organic network
structure (Fig. 3). The distance between two parallel
R
n
Ph
Ph
Ph OH
R = CH3, 1a
= Ph, 1b
n = 2, 1c
= 1, 1d
O
O
O
(1)
O
O
O
Ph
Ph
Ph
Ph
Ph
O
O
O
(1e)
(1f)
(1g)
O
O
O
O
Ph
Ph
O
Ph
Ph
O
OEt
O
(1h)
O
(1i)
O
(1j)
Experimental
˚
staircases is 3.959 A, while distance between each stair is
All the chemicals were obtained from Sigma–Aldrich
Chemical Co. and used as obtained. Intensity data of the
single crystals were collected with Bruker Smart Apex-II
CCD diffractometer using graphite monochromated MoKa
˚
˚
7.628 A. The rectangular boxes of dimensions 8.161 A ·
˚
5.337 A, formed by the two oppositely oriented molecules
in the asymmetric unit constitute the pillar of the staircase.
The ORTEP diagram of 1a with atomic numbering
scheme is shown in Fig. 4. In 1a also the asymmetric unit
consists of two molecules like its starting compound 1. But
unlike compound 1 it shows the presence of C–HÁÁÁÁO type
hydrogen bonding network instead of strong O–HÁÁÁÁp
type hydrogen bonding to form the dimeric unit, due to the
absence of alcoholic hydrogen. Oxygen atoms of xanthene
unit participate in intermolecular hydrogen bonding
network, unlike compound 1. C–HÁÁÁÁO type hydrogen
bonding forms the linear array along crystallographic a
axis. The C–HÁÁÁÁO type hydrogen bonding in parallel lin-
ear array is pointed in the opposite directions (Fig. 5). Each
of these linear arrays are connected to the neighboring
oppositely directed arrays through the formation of C–
HÁÁÁÁp type of hydrogen bonding. Overall hydrogen bond-
ing network results in the formation of 3D alternate
continuous wave-like tape and discrete box network
(Fig. 6). One of the two molecules in the asymmetric unit
˚
radiation (k = 0.71073 A) at 298 K. Cell parameters were
retrieved using SMART [18] software and refined with
SAINT [18] on all observed reflections. Data reduction was
performed with the SAINT software and corrected for
Lorentz and polarization effects. Absorption corrections
were applied with the program SADABS [19]. The struc-
ture was solved by direct methods implemented in
SHELX-97 [20] program and refined by full-matrix least-
squares methods on F2. All non-hydrogen atomic positions
were located in difference Fourier maps and refined
anisotropically. The hydrogen atoms were placed in their
geometrically generated positions. All the colourless
crystals were isolated from ethyl acetate and hexane mix-
ture (8:2) at room temperature. All the data collections
were done at room temperature. The important crystallo-
graphic parameters of the reported compounds are given in
Table 1 and 2.
˚
˚
forms the box of dimension 6.580 A · 5.887 A.
Results and discussion
The ORTEP diagram of 1b with atomic numbering
scheme is shown in Fig. 7. In 1b the asymmetric unit
consists of one molecule unlike 1a, due to the presence
of extra bulky benzene ring in the pendant arm. Two
phenyl rings are almost perpendicular and oriented in the
In order to delineate our objectives of supramolecular self-
assembly, we have carried single crystal X-ray diffraction
studies of all the xanthenol derivatives 1a–1j along with its
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