802
J Chem Crystallogr (2011) 41:801–805
thionyl chloride for 5 h. The reaction mixture was rotor-
evaporated to dryness in vacuum to obtain nicotinyl chlo-
ride in quantitative yield.
H6
H5
H7
H4
O
H3
Nicotinyl chloride (2.1 g, 1.46 mmol) was treated with
equimolar amounts of ethyl anthranilate (2.4 g) and two
equivalents of triethylamine as the base and dichloro-
methane as the solvent under reflux conditions for 5 h. The
product mixture was cooled to 25 °C and washed with dil.
HCl followed with water and brine. The solvent was
evaporated in vacuo and the residue chromatographed on
silica gel using hexane and ethylacetate as the eluant sys-
tem (refer Scheme 1). The product ‘1’ obtained (3.2 g,
N
H
H8
N
H1
O
O
H 2
Zn
N
Cl
H 2
Cl
H1
O
O
H
N
H8
H7
H3
O
H4
1
H5
80% yield) was further characterized by H-NMR CDCl3
H6
(d 1.45 CH2CH3, 4.45 CH2CH3, 12.23, CONH, Ar 1Hs,
7.00 to 9.40 ppm), UV–Vis k-max 278, and 322 nm and
MS (m/z 270, M?).
Fig. 1 Chemical structure of 2 showing hydrogen labels
‘1’, niacinamide, and ZnCl2 were mixed in a ratio of
1:1:0.5 in methanol and stirred overnight at 25 °C. The
reaction mixture was concentrated to 15 mL volume and
allowed to cool at 4 °C for 48 h. Compound ‘2’ crystallized
out (Fig. 1) and was characterized by X-ray crystallogra-
phy. The 1H NMR spectra of ‘1’ & ‘2’ are similar in
appearance but for the aromatic region (refer Table 1). The
signals for the protons H1, H2 and H3 are down shifted in
‘2’ as compared to ‘1’ and this is expected since com-
plexation with zinc would decrease the electron density in
the pyridine ring (refer to Table 1 for chemical shift val-
ues). The signals for the aromatic protons UV–Vis peak
maxima for ‘2’ (kmax: 276 and 316 nm) show blue shifts
as compared to that of the free ligand ‘1’. The MS spec-
trum for ‘2’shows intense peaks for M-(HCl), (m/z 639);
and M-2 (HCl), (m/z 603) fragments.
a Enraf–Nonius Mach-3 diffractometer using a graphite
˚
monochromator for the Mo-Ka radiation (k = 0.71071 A).
The crystal structure was solved by direct methods using
the SHELXTL program [9] and refined by full matrix least
squares on F2 (CCDC 690286). All non-hydrogen atoms
were refined anisotropically. Hydrogen atoms were fixed
using HFIX and were refined isotropically. Hydrogen bond
analysis was carried out using the PLATON routine [10].
Crystal structure data of the complex is given in Table 2.
Energy calculation and energy minimization were carried
out using PM6 routine on the title compound using
MOPAC 2007 [11]. The geometric coordinates obtained
from X-ray structure was used as the starting coordinates
for energy minimization.
CCDC 690286 contains the supplementary crystallo-
graphic data for this complex. These data can be obtained
cif or by emailing data_request@ccdc.cam.ac.uk, or by
contacting The Cambridge Crystallographic Data Centre,
12, Union Road, Cambridge CB2 1EZ, UK; fax: ?44 1223
336033.
The crystals obtained were examined under an optical
microscope and high quality crystals suitable for single-
crystal diffraction were separated out. X-ray diffraction
intensities were measured at room temperature (298 K) on
O
O
SOCl2
Reflux
5 h
OH
Cl
Results and Discussion
N
N
Nicotinic Acid
The complex crystallizes in centrosymmetric triclinic
system (lattice parameters, a = 7.787(3), b = 13.468(1),
c = 15.735(1), a = 110.25(1), b = 95.11(1), c = 99.32(1))
with two molecules per unit cell. The asymmetric unit
comprises of the whole molecule (see Fig. 2.). During the
synthesis, both EAN and nicotinamide were added in equi-
molar concentrations to form a co-complex with zinc.
However, only EAN forms complex with zinc, possibly
indicating stronger binding power of EAN over nicotin-
amide. Important structural parameters are given in the
Table 2. Like most zinc complexes, this complex exhibits a
1
H
2
3
H
H
O
O
N
O
O
H
N
H
N
8
H
H
H
O
4
H
7
H
CH2Cl2, Reflux, 5 h
5
1
H
6
Scheme 1 Synthesis of Ethylanthranilatonicotinamide (EAN)
123