Journal of Chemical Crystallography, Vol. 29, No. 6, 1999
Structure of N,N
,N؆-tris(carboxymethyl)-1,3,5-
benzenetricarboxamide trihydrate
Bing Gong,(1)* Chong Zheng,(2)* and Yinfa Yan(1)
Received March 15, 1999
The title compound, C15H15N3O9 и 3H2O, crystallizes in the centrosymmetric space group R3
with a ϭ 13.642(5), b ϭ 13.642(5), c ϭ 18.692(5) A, Dcalc ϭ 1.440 g cm3, and z ϭ 6. An
˚
extensive three-dimensional hydrogen bonded network is observed. The network arises from
15 hydrogen bonds per asymmetric unit. Six identical NUHиииO hydrogen bonds are formed
between two triacid molecules, which results in the face-to-face dimerization of the two
triacid molecules. The dimers form extended sheets through hydrogen bond interaction with
water molecules. The sheets are held together by hydrogen bonds via the water molecules.
The planes of the benzenoid ring are parallel to each other.
KEY WORDS: Triacid molecules; hydrogen bond interaction; water molecules.
Introduction
The title compound was crystallized from water by
gas-phase neutralization2 of a solution of the triacid
In our study of hydrogen bonded molecular as-
in aqueous sodium hydroxide.
semblies, the title compound, (I), was synthesized. It
crystallizes in the centrosymmetric space group R3,
a space group not very common for organic com-
pounds. But, because of the three carboxyl groups
in the title compound, the space group R3 provides
the best packing arrangement in the unit cell. How-
ever, the three carboxyl groups of the triacid do not
form an eight-membered, dimeric hydrogen bonded
cycle as in other compounds we have studied.1
Data collection was carried out on an Enraf-
Nonius CAD4 diffractometer. Table 1 lists the data
collection and refinement details. Fractional atomic
coordinates and equivalent isotropic thermal param-
eters are listed in Table 2. Selected bond lengths and
angles are listed in Table 3.
Results and discussion
Experimental
A view of the hydrated molecule is shown in
Fig. 1. The 3 axis passes through the center of the
molecule shown in Fig. 2. As listed in Table 4,
there are 15 hydrogen bonds in this structure, which
fall into three identical, symmetry-related sets. Each
set corresponds to the five H-bonds formed by the
donors and acceptors of one of the three arms
attached to the benzenoid ring. The triacid molecule
has the conformation in which all three arms are
pointed to one side of the plane of the benzenoid
ring. Such a conformation results in a self-comple-
The triacid was synthesized by treating 1,3,5-
benzenetricarbonyl trichloride with glycine methyl
ester in CHCl3. The triester product, upon hydrolysis
with 3 equivalents of NaOH in water, gave the triacid.
(1) Department of Chemistry, University of Toledo, Toledo, OH
43606, USA.
(2) Department of Chemistry and Biochemistry, Northern Illinois
University, DeKalb, Illinois 60115.
* To whom correspondence should be addressed.
649
1074-1542/99/0600-0649$16.00/0 1999 Plenum Publishing Corporation
Gong, Bing
