Synthesis, spectroscopic characterization, crystal structures, and theoretical studies of (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone

Article abstract of DOI:10.1007/s11224-010-9637-3

Two thiosemicarbazones, (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone (24-MBTSC (1)) and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone (25-MBTSC (2)), derived from 2,4-dimethoxybenzaldehyde and 2,5-dimethoxybenzaldehyde, respectively, with thiosem

Full text of DOI:10.1007/s11224-010-9637-3

Struct Chem (2010) 21:995–1003
DOI 10.1007/s11224-010-9637-3
ORIGINAL RESEARCH
Synthesis, spectroscopic characterization, crystal structures,
and theoretical studies of (E)-2-(2,4-dimethoxybenzylidene)
thiosemicarbazone and (E)-2-(2,5-dimethoxybenzylidene)
thiosemicarbazone
•
Aliakbar Dehno Khalaji Gholamhossein Grivani
•
•
Samaneh Jalali Akerdi Kazuma Gotoh
•
•
Hiroyuki Ishida Hossein Mighani
Received: 5 January 2010 / Accepted: 11 June 2010 / Published online: 4 July 2010
Ó Springer Science+Business Media, LLC 2010
Abstract Two thiosemicarbazones, (E)-2-(2,4-dimethoxy-
benzylidene)thiosemicarbazone (24-MBTSC (1)) and (E)-2-
(2,5-dimethoxybenzylidene)thiosemicarbazone (25-MBTSC
(2)), derived from 2,4-dimethoxybenzaldehyde and 2,5-dime-
thoxybenzaldehyde, respectively, with thiosemicarbazide have
been synthesized and their structures were characterized by
elemental analyses, FT-IR, 1H NMR spectroscopy, and X-ray
single-crystal diffraction analysis. Molecular orbital calcula-
tions have been carried out for 1 and 2 by using an ab initio
method (HF) and also density functional method (B3LYP) at
6-31G basis set. Compound 1 crystallizes in the monoclinic
Keywords Thiosemicarbazone Á
2,4-Dimethoxybenzaldehyde Á
2,5-Dimethoxybenzaldehyde Á Crystal structure Á
Configuration Á HF Á Density functional theory (DFT)
Introduction
Thiosemicarbazide H2N–NH–C(=S)–NH2 is a promising
unit to synthesize new polyfunctional organic compounds,
named as thiosemicarbazone, that are used as a precursor to
produce new transition metal complexes with a wide range
of application in recent years [1]. They have been evalu-
ated over the last 50 years as antiviral, antibacterial, and
anticancer therapeutics, and biological activities of them
are a function of parent aldehyde or ketone moiety [2–7].
Thiosemicarbazone is an important group of multidentate
ligands and usually coordinates with the metal through the
imine nitrogen and sulfur atom [8–24] (Scheme 1).
Although a series of free thiosemicarbazone compounds
and their complexes have been investigated crystallo-
graphically [25–27], herein, we report the syntheses,
characterization, and crystal structure of two thiosemicar-
bazone compounds derived from 2,4-dimethoxybenzalde-
hyde and 2,5-dimethoxybenzaldehyde (Scheme 2). The
structural analyses were carried out utilizing elemental
analyses (CHN), FT-IR and 1H NMR spectroscopy and
X-ray diffraction techniques.
˚
system, space group P21/c, with a = 8.1342(5) A, b =
˚
˚
18.1406(10) A, c = 8.2847(6) A, b = 109.7258(17)°, V =
3
1150.75(12) A , and Z = 4, whereas compound 2 crystallizes
˚
in the orthorhombic system, space group Pbca, with a =
˚
˚
11.0868(6) A, b = 13.1332(6) A, c = 15.9006(8) A, V =
˚
3
2315.2(2) A , and Z = 8. The compounds 1 and 2 displays a
˚
trans-configuration about the C=N double bond.
A. D. Khalaji (&) Á H. Mighani
Department of Chemistry, Faculty of Science,
Golestan University, Gorgan, Iran
e-mail: alidkhalaji@yahoo.com
G. Grivani Á S. J. Akerdi
Experimental
School of Chemistry, Damghan University,
Damghan 36715-364, Iran
All reagents and solvents for synthesis and analysis were
commercially available and used as-received. Infrared spec-
tra were recorded as KBr pellets on a FT-IR Perkin-Elmer
K. Gotoh Á H. Ishida
Department of Chemistry, Faculty of Science,
Okayama University, Okayama 700-8530, Japan
123

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Struct Chem (2010) 21:995–1003
NH2
S
NH2
S
Anal. Calc. for C10H13N3O2S: C, 50.20; H, 5.48; N,
17.56%. Found: C, 49.58; H, 5.35; N, 18.0%. IR (KBr
pellet, cm-1): tN–H: 3443, 3243, 3139, tC–H (aromatic):
3009, tC–H (aliphatic): 2967, tC–H (imine): 2826, tC=N
(imine) 1613, tC–C and C–N: 1429–1590, tC–O: 1323,
H
R
R
N
R
R
N
N
N
M
M
1
M = Cu(II), Zn(II), Co(II) and Ni(II)
tC=S: 1210. H NMR (DMSO, d(ppm)): 11.26 (s, 1H, N–
H); 8.26 (s, 1H, –CH=N–); 7.99 (s, 1H, NH2); 7.96 (s, 1H,
NH2); 7.82 (s, 1H, Ar–H); 6.54 (t, 2H, Ar–H), 3.77 (s, 6H,
2CH3–O–).
NH2
H
NH2
S
H
N
R
N
R
R
N
N
S
N
N
25-MBTSC (2): Reactant materials: Thiosemicarbazide,
2,5-dimethoxybenzaldehyde. Colorless crystals. Yield: 90%.
Anal. Calc. for C10H13N3O2S: C, 50.20; H, 5.48; N,
17.56%. Found: C, 50.10; H, 5.37; N, 17.58%. IR (KBr
pellet, cm-1): tN–H: 3432, 3316, 3175, tC–H (aromatic):
3014, tC–H (aliphatic): 2963, tC–H (imine): 2837, tC=N
(imine): 1610, tC–C, and C–N: 1431–1597, tC–O: 1364,
M
M
M
M
R
NH2
NH2
H
N
H
N
R
R
R
R
S
S
M
M
1
tC=S: 1222. H NMR (DMSO, d(ppm)): 11.39 (s, 1H, N–
M = Ag(I) and Cu(I)
H); 8.35 (s, 1H, –CH=N–); 8.15 (s, 1H, NH2); 8.05 (s, 1H,
NH2); 7.61 (s, 1H, Ar–H); 6.94 (t, 2H, Ar–H), 3.73 (s, 6H,
2CH3–O–).
Scheme 1 Different modes of thiosemicarbazone in transition metal
complexes
S
S
X-ray structure analysis
H
H
N
N
H3C
H3C
O
O
N
NH2
H3C
O
N
NH2
Crystallographic measurements for both compounds were
done with Rigaku RAXIS-RAPID II diffractometer, with
˚
graphite monochromataed Mo Ka radiation (k = 0.71075 A)
at180 K. The crystal structuresweresolvedbydirectmethods
using program SHELXS97 [28] and refined by full-matrix
least-squares technique (SHELXL97 [28]) based on F2 with
atomic anisotropic thermal parameters for all non-hydrogen
atoms. The molecular structure plots were prepared by using
the ORTEP-3 [29]. C-bound H atoms were placed in geo-
O
H3C
25-MBTSC (2)
24-MBTSC (1)
Scheme 2 Chemical structure of the title compounds
˚
metrically idealized positions (C–H = 0.95 or 0.98 A) and
allowed to ride on their parent atoms, with Uiso(H) =
1.2Ueq(C) or 1.5Ueq(methyl C). Crystallographic data and
details of the data collection and structure refinements are
listed in Table 1.
spectrophotometer. Elemental analyses were carried out
1
using a Heraeus CHN-O-Rapid analyzer. H NMR spectra
were measured on a BRUKER DRX-250 AVANCE spec-
trometer at 250 MHz and all chemical shifts are reported in
d units downfield from TMS.
Theoretical methods
Synthetic procedures of 24-MBTSC (1)
and 25-MBTSC (2)
Molecular parameters (bond distances, torsion and bond
angles, and the theoretically structures) of the title com-
pounds 24-MBTSC (1) and 25-MBTSC (2) have been
computed in an ab initio comparative study involving
HF and density functional theory (DFT) calculations.
The 6-31G basis set was employed. Several useful concepts
derived from DFT have been applied to the study of
the chemical reactivity of the more stable forms of the
isomeric thiosemicarbazone. The parameters have been
obtained from calculations made in the context of the
Hartree–Fock and nonlocal (B3LYP) density functional
approximations. The results were compared with the
Compounds 1 and 2 were synthesized by addition of
the 2,4-dimethoxybenzaldehyde or 2,5-dimethoxybenzal-
dehyde (0.2 mmol, in 5 mL ethanol) to a solution of thi-
osemicarbazide (0.2 mmol, 10 mL ethanol). The resulted
solution was stirred in air at 323 K for about 1.5–2 h and
then was left at room temperature for several days without
disturbance to yield single crystals of compounds. The
obtained crystals were filtered off, washed with EtOH.
24-MBTSC (1): Reactant materials: Thiosemicarbazide,
2,4-dimethoxybenzaldehyde. Colorless crystals. Yield: 88%.
123

Struct Chem (2010) 21:995–1003
997
stable in the solid state for several months. The stability of
dissolved compound is very much shorter than in the solid
state and depends on the nature of the solvent. The title
compounds 1 and 2 are very slightly soluble in common
organic solvents such as acetonitrile, methanol, chloroform,
and dichloromethane but completely soluble in DMF and
DMSO.
Table 1 Crystal structure and refinement of 24-MBTSC (1) and 25-
MBTSC (2)
1
2
Empirical formula
Formula weight
C10H13N3O2S
239.29
C10H13N3O2S
239.29
Crystal system,
space group
Monoclinic, P21/c
Orthorhombic, Pbca
˚
a (A)
8.1342(5)
18.1406(10)
8.2847(6)
90.00
11.0868(6)
13.1332(6)
15.9006(8)
90.00
FT-IR spectra
˚
b (A)
˚
c (A)
The FT-IR data of the compounds are given in ‘‘Experi-
mental’’ section and summarized in Table 2. Vibration
bands with the wave numbers of 3443, 3243, 3139 and 3432,
3316, 3175 cm-1 (tN–H), 1323 and 1364 cm-1 (tC–O),
1210 and 1222 cm-1 (tC=S) were observed for compounds
1 and 2, respectively. The difference between these bands
shows the presence of different hydrogen bonds in these
compounds. Strong vibration band at 1613 and 1610 cm-1
was observed in 1 and 2, respectively, which is accountable
for the existence C=N imine bond.
a
b
c
109.7258(17)
90.00
90.00
90.00
3
˚
V (A )
1150.75(12)
4
2315.2(2)
8
Z
Crystal size (mm3)
qcalc (g/cm3)
l (mm-1
0.35 9 0.30 9 0.21
1.381
0.35 9 0.35 9 0.15
1.373
)
0.271
0.269
Index ranges
-11 B h B 11
-23 B k B 25
-11 B l B 11
18734, 3354
-15 B h B 15
-16 B k B 18
-22 B l B 22
43088, 3369
1H NMR spectra
Reflection number,
total
1
The H NMR spectra of the title compounds 1 and 2 were
Rint
0.0213
157
0.0163
157
recorded using DMSO as the solvent and the data were
summarized in ‘‘Experimental’’ section, and are depicted in
Fig. 1. The N–H and azomethine protons are observed as a
singlet at 11.26 and 8.26 ppm, respectively, for compound
1 and 11.39 and 8.325 ppm, respectively, for compound 2.
The two amine protons (NH2) have different hydrogen
bonds as observed at 7.99 and 7.96 ppm for compound 1
and 8.15 and 8.05 ppm for compound 2. The phenyl pro-
tons are observed as two groups; the first group observed as
a singlet bands at 7.82 ppm for compound 1 and 7.61 ppm
compound 2, and the second group observed as a triplet
bands at 6.54 ppm for compound 1 and 6.94 ppm com-
pound 2. All the aliphatic protons (CH3–O– groups) in the
Number of
parameters
Goodness-of-fit on
F2
1.064
1.039
Final R indices
[I [ 2r (I)]
Final R indices
R1 = 0.0315,
wR2 = 0.0845
R1 = 0.0315,
wR2 = 0.0876
R1 = 0.0343,
wR2 = 0.0866
R1 = 0.0339,
wR2 = 0.0895
(all data)
24-MBTSC (1) w = 1/[s2(F2o) ? (0.0499P)2 ? 0.2515P] P =
(F2o ? 2F2c)/3
25-MBTSC (2) w = 1/[s2(F2o) ? (0.0543P)2 ? 0.5575P] P =
(F2o ? 2F2c)/3
existing experimental evidence on thiosemicarbazone and
related compound. The results indicate that B3LYP with
the 6-31G basis set is a useful method [30–33]. All HF and
DFT calculations were performed using the Gaussian 98
R-A.9 package [34].
Table 2 Selected vibration bands of 24-MBTSC (1) and 25-MBTSC
(2)
Vibration bands
1
2
tN–H
3443, 3243, 3139
3009
3432, 3316, 3175
3014
Results and discussion
tC–H (aromatic)
tC–H (aliphatic)
tC–H (imine)
tC=N (imine)
tC–C and C–N
tC–O
2967
2963
Synthesis
2826
2837
1613
1610
Both compounds 1 and 2 were prepared in yield 88 and
90%, respectively, by reaction of 2,4-dimethoxybenzalde-
hyde or 2,5-dimethoxybenzaldehyde and thiosemicarbazide
in at mild condition in ethanolic solution. They are air-
1429–1590
1323
1431–1597
1364
tC=S
1210
1222
123

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Struct Chem (2010) 21:995–1003
Fig. 3 ORTEP-3 drawing of 2 with the atom numbering scheme.
The thermal ellipsoids are drawn at the 50% probability level
C10/S1/N3) in the title molecules 1 and 2 are essentially
coplanar, the dihedral angles between them being 2.98(4)°
and 9.04(4)°, respectively, for 1 and 2, so that the structure
provides p-conjugation between the benzene ring and the
thiosemicarbazide fragment of the compounds.
Fig. 1 1H NMR spectra of the title compounds 1 and 2
The C1–C9 bond length of 1 and 2 are 1.4566(12) and
´
˚
1.4636(12) A, which are shorter than the corresponding bond
´
˚
in other uncoordinated thiosemicarbazone (1.498(3) A, [35])
title compounds 1 and 2 as a singlet bands are observed at
3.77 ppm for compound 1 and 3.73 ppm for compound 2.
but is almost similar to ones in other uncoordinated thiosem-
´
´
˚
˚
icarbazone (1.445(3) A [26] and 1.468(2) A [27]). The C10–
´
´
˚
˚
Crystal structures of 1 and 2
S1 bond distance of 1.6961(9) A in 1 and 1.6950(9) A in 2 is
almost similar to those in other uncoordinated thiosemicar-
´
´
˚
˚
Figures 2 and 3 depict the molecular structures of 1 and 2,
respectively. Bond distances, bond, and torsion angles are
given in Tables 3, 4, and 5, respectively. The benzene ring
(C1–C6) and the thiosemicarbazide fragment (C9/N1/N2/
bazone (1.674(2) A [26], 1.690(1) A [27]) and is intermediate
´
˚
between the values of 1.82 A for a C–S single bond and
˚
1.56 A for C=S double bond. The terminal nitrogen atoms N1
´
and N3 of the thiosemicarbazide fragment are in an antiperi-
planar conformation with respect to the C10–N2, whereas the
middle nitrogen atom N2 of the thiosemicarbazide and C1 of
the benzaldehyde fragment are in a trans-configuration with
respect to the imine C9=N1. Structural data show that the N1–
´
´
˚
˚
C9distanceis1.2866(11) Ain1 and1.2809(12) Ain2, which
is longer or shorter than the distance for C=N double bond in
´
˚
some thiosemicarbazone compounds, 1.276(3) A [26] and
´
˚
1.330(2) A [27], but well in the range of C=N double bond
distance found in some thiosemicarbazone compound,
´
´
˚
˚
1.281(3) A [35]. The N2–C10 bond length 1.3467(11) A in 1
´
˚
and 1.3507(11) A in 2 is shorter or longer than the distance for
C=N double bond in some thiosemicarbazone compounds,
´
´
´
˚
˚
˚
1.360(2) A [26], 1.353(3) A [35], and 1.342(3) A [27].
The bond angle C1–C9–N1 is 120.81(8)° in 1 and 120.20(8)°
in 2, and they are consistent with the sp2 hybrid character for
Fig. 2 ORTEP-3 drawing of 1 with the atom numbering scheme.
The thermal ellipsoids are drawn at the 50% probability level
123

Struct Chem (2010) 21:995–1003
999
Table 3 Bond distances of 24-MBTSC (1) and 25-MBTSC (2)
1
HF/6-31G
B3LYP/6-31G
2
HF/6-31G
B3LYP/6-31G
S1–C10
O1–C2
O1–C7
O2–C4
O2–C8
N1–C9
N1–N2
N2–C10
N3–C10
C1–C6
C1–C2
C1–C9
C2–C3
C3–C4
C4–C5
C5–C6
1.6961(9)
1.746
1.367
1.433
1.364
1.431
1.269
1.375
1.342
1.327
1.387
1.403
1.461
1.379
1.390
1.387
1.386
1.730
1.380
1.453
1.385
1.453
1.289
1.380
1.371
1.348
1.404
1.421
1.454
1.392
1.403
1.402
1.395
1.6950(9)
1.736
1.363
1.427
1.375
1.425
1.267
1.370
1.344
1.326
1.392
1.401
1.466
1.388
1.392
1.380
1.386
1.728
1.385
1.450
1.393
1.450
1.298
1.376
1.371
1.347
1.400
1.417
1.463
1.394
1.393
1.386
1.393
1.3625(11)
1.4273(11)
1.3582(12)
1.4339(14)
1.2866(11)
1.3836(11)
1.3467(11)
1.3259(12)
1.4008(13)
1.4039(12)
1.4566(12)
1.3972(12)
1.3909(13)
1.3990(14)
1.3788(14)
1.3679(11)
1.4203(12)
1.3772(11)
1.4298(11)
1.2809(12)
1.3772(10)
1.3507(11)
1.3259(12)
1.3941(12)
1.4099(12)
1.4636(12)
1.3890(13)
1.3943(14)
1.3892(13)
1.3907(12)
Table 4 Bond angles of 24-MBTSC (1) and 25-MBTSC (2)
1
HF/6-31G
B3LYP/6-31G
2
HF/6-31G
B3LYP/6-31G
C2–O1–C7
C4–O2–C8
C5–O2–C8
C9–N1–N2
C10–N2-N1
C6–C1–C2
C6–C1–C9
C2–C1–C9
O1–C2–C3
O1–C2–C1
C3–C2–C1
C4–C3–C2
O2–C4–C3
O2–C4–C5
C3–C4–C5
C6–C5–C4
C5–C6–C1
C2–C3–C4
C5–C4–C3
O2–C5–C4
O2–C5–C6
C4–C5–C6
C5–C6–C1
N1–C9–C1
N3–C10–N2
N3–C10–S1
N2–C10–S1
117.75(7)
117.67(9)
–
121.78
121.84
–
119.26
118.65
–
117.86(8)
–
121.47
–
118.98
–
117.52(7)
115.60(8)
119.08(8)
119.40(8)
121.38(8)
119.22(8)
124.78(8)
115.48(8)
119.73(8)
–
118.20
118.46
121.10
118.42
121.95
119.07
123.83
116.10
119.78
–
118.54
117.99
121.06
118.14
122.14
119.23
123.90
115.83
119.75
–
115.14(8)
119.33(8)
117.68(8)
121.96(8)
120.36(8)
122.86(8)
115.93(8)
121.21(8)
119.23(8)
123.74(9)
115.63(9)
120.63(8)
119.14(9)
122.07(9)
–
118.32
121.20
117.94
122.52
119.53
122.90
116.10
121.55
119.60
115.51
124.36
120.11
118.74
122.86
–
117.55
121.19
117.65
122.72
119.61
123.18
115.14
121.77
119.62
115.11
124.85
120.03
118.65
122.46
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
120.42(8)
119.84(8)
123.97(8)
115.79(8)
120.23(8)
120.34(8)
120.20(8)
116.91(8)
123.54(7)
119.54(7)
120.36
119.91
123.54
115.67
119.59
121.55
121.83
116.63
123.37
119.99
120.39
119.91
124.48
115.50
120.53
121.63
121.24
116.27
124.56
119.95
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
120.81(8)
117.48(8)
122.98(7)
119.53(7)
122.20
116.96
123.01
120.02
122.13
115.48
124.43
122.08
123

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Struct Chem (2010) 21:995–1003
Table 5 Torsion angles of 24-MBTSC (1) and 25-MBTSC (2)
1
HF/6-31G
B3LYP/6-31G
2
HF/6-31G
B3LYP/6-31G
C9–N1–N2–C10
C7–O1–C2–C3
C7–O1–C2–C1
C6–C1–C2–O1
C9–C1–C2–O1
C6–C1–C2–C3
C9–C1–C2–C3
O1–C2–C3–C4
C1–C2–C3–C4
C8–O2–C4–C3
C8–O2–C4–C5
C2–C3–C4–O2
C2–C3–C4–C5
O2–C4–C5–C6
C3–C4–C5–C6
C2–C3–C4–C5
C8–O2–C5–C4
C8–O2–C5–C6
C3–C4–C5–O2
C3–C4–C5–C6
O2–C5–C6–C1
C4–C5–C6–C1
C2–C1–C6–C5
C9–C1–C6–C5
N2–N1–C9–C1
C6–C1–C9–N1
C2–C1–C9–N1
N1–N2–C10–N3
N1–N2–C10–S1
-179.00(8)
2.53(13)
-177.80(8)
-178.29(8)
1.33(12)
1.39(13)
-178.98(8)
178.67(8)
-0.99(14)
2.82(15)
-177.72(9)
179.20(9)
-0.23(14)
-178.48(9)
0.99(15)
–
-180.00
0.02
179.99
0.02
175.39(9)
3.14(15)
-179.99
0.03
179.99
0.01
-179.90
179.38
0.00
179.99
177.83
0.00
-177.96(9)
179.50(8)
-0.56(12)
-1.55(13)
178.40(9)
-179.59(9)
1.56(15)
–
179.99
180.00
0.00
179.98
180.00
0.00
0.872
-180.00
179.82
0.09
1.03
0.89
0.00
-180.00
178.76
0.34
-180.00
-178.42
0.23
-180.00
-180.00
0.00
-179.21
1.08
-179.97
0.43
–
–
–
–
–
-179.92
0.36
-179.93
0.5
–
–
–
–
–
–
179.70
0.02
179.82
0.31
–
–
–
–
–
–
–
–
-0.08(15)
5.75(13)
-174.43(8)
178.39(9)
-1.43(15)
-178.40(8)
1.43(14)
0.06(13)
-179.89(8)
-178.53(8)
8.70(14)
-171.25(9)
3.09(13)
-175.94(7)
0.65
0.00
–
–
–
0.04
0.00
–
–
–
179.92
179.92
1.081
-179.08
1.25
-180.00
180.00
0.00
–
–
–
–
–
–
–
–
–
-180.00
0.00
-0.56(15)
-0.61(14)
179.77(9)
-179.32(8)
-1.59(14)
178.80(8)
1.90(13)
-176.70(6)
0.81
0.74
1.24
1.5
1.64
0.00
178.70
-180.00
0.02
179.42
-179.97
0.04
178.85
-178.98
0.01
180.00
-179.98
0.01
-179.99
0.02
-179.96
0.02
-179.99
0.01
-179.99
0.01
-179.98
-179.98
-179.99
-179.99
Table 6 Hydrogen bonds of 24-MBTSC (1) and 25-MBTSC (2)
C9 atom (123.3(2)° [26], 118.89(11)° [27], and 114.93(18)°
[35]).
D–HÁÁÁA
D–H
HÁÁÁA
DÁÁÁA
D–HÁÁÁA
The geometrical details of hydrogen bonds in 1 and 2
are summarized in Table 6. In each compound, there is an
intramolecular N–HÁÁÁN hydrogen bond (N3–H3AÁÁÁN1),
which supports an antiperiplanar conformation of N1 and
N3 atoms with respect to the C10–N2 bond. In the crystal
structure of 1, the molecules are connected by N–HÁÁÁS
hydrogen bonds (N2–H2ÁÁÁS1 and N3–H3BÁÁÁS1) to form a
chain running along the c-axis (Fig. 4). Between the
chains, the molecules are arranged in an antiparallel man-
ner (Fig. 5), but no significant interaction is observed.
In the structure of 2, the primary intermolecular interaction
is formed between the amide and methoxyl groups (N3–
H3BÁÁÁO2), which leads to a different molecular packing
from 1. The N–HÁÁÁS hydrogen bonds are also observed but
24-MBTSC (1)
N3–H3AÁÁÁN1
N2–H2ÁÁÁS1i
0.820(18) 2.269(16) 2.6368(12) 107.7(13)
0.909(15) 2.511(15) 3.4159(9)
0.865(16) 2.594(16) 3.4465(9)
173.5(13)
168.7(15)
N3–H3BÁÁÁS1ii
25-MBTSC (2)
N3–H3AÁÁÁN1
0.871(15) 2.254(13) 2.6212(12) 105.2(11)
N3–H3BÁÁÁO2iii 0.871(15) 2.155(15) 2.9745(11) 156.6(14)
N2–H2ÁÁÁS1iv
N3–H3AÁÁÁS1v
C4–H4ÁÁÁO1vi
0.849(14) 2.718(14) 3.5439(8)
165.0(13)
0.871(15) 2.825(15) 3.5318(9)
139.3(11)
0.95
2.51
3.3200(13) 143
Symmetry codes: (i) x, ‘ - y, 1/2 ? z; (ii) x, ‘ - y, -1/2 ? z;
(iii) -1/2 ? x, 3/2 - y, 1 – z; (iv) -x, 1 - y, 1 - z; (v) 1/2 ? x, 3/
2 - y, 1 - z; (vi) 1/2 ? x, y, ‘ - z
123

Struct Chem (2010) 21:995–1003
1001
Fig. 4 A partial packing
diagram of 1, showing a
molecular chain formed by the
intermolecular N–HÁÁÁS
hydrogen bonds (dashed lines).
Symmetry codes: (i) x, ‘ - y,
1/2 ? z; (ii) x, ‘ - y, -1/
2 ? z
rather weak as compared with those in 1. The molecules
are linked through the N–HÁÁÁO and N–HÁÁÁS hydrogen
bonds (N3–H3BÁÁÁO2 and N3–H3AÁÁÁS1), forming a zigzag
chain along the a-axis (Fig. 6). The chains related by an
inversion center are connected by a pair of N–HÁÁÁS inter-
actions (N2–H2ÁÁÁS1) to form a layer expanding parallel
to the ab plane (Fig. 7). The layers are further lined by
C–HÁÁÁO interactions (C4–H4ÁÁÁO1).
Theoretical studies
The B3LYP/6-31G optimized structure of the title com-
pounds 1 and 2 discussed during the computational inves-
tigations is presented in Figs. 8 and 9, respectively. Some
optimized geometric parameters are also listed in Tables 2–
4. However, the theoretical calculations are performed in
gaseous phase and the experimental results are in a solid
state, comparing the theoretical with the experimental val-
ues of 1 and 2 shows that there is quite resemblance in the
structural parameters (such as bond distances, bond angles,
etc.) of the title compounds obtained theoretically and
experimentally obtained by X-ray crystallography.
Fig. 5 A packing diagram of 1, viewed along the a-axis. H atoms
except N-bound ones have been omitted. The N–HÁÁÁS hydrogen
bonds are indicated by dashed lines
123

1002
Struct Chem (2010) 21:995–1003
Fig. 6 A partial packing diagram of 2, showing a molecular chain formed by the intermolecular N–HÁÁÁO and N–HÁÁÁS hydrogen bonds (dashed
lines). Symmetry codes: (iii) -1/2 ? x, 3/2 - y,1 - z; (v) 1/2 ? x, 3/2 - y, 1 - z
Fig. 8 The B3LYP/6-31G optimized structure of 1
Supplementary data
Crystallographic data (excluding structure factors) for
the structure reported in this article have been deposited
Fig. 7 A partial packing diagram of 2, showing N–HÁÁÁS hydrogen
with the Cambridge Crystallographic Center, CCDC Nos.
bonds (dashed lines) formed between the molecular chains. Symme-
try code: (iv) -x, 1 - y, 1 - z
757173 (1) and 757174 (2). Copies of the data can be
123

Struct Chem (2010) 21:995–1003
1003
8. Kolotilov SV, Cador O, Golhen S, Shvets O, Ilyin VG,
Pavlishchuk VV, Ouahab L (2007) Inorg Chim Acta 360:1883–
1889
9. Nunez-Montenegro A, Carballo R, Vazquez-Lopez EM (2008)
Polyhedron 27:2867–2876
10. Nunez-Montenegro A, Carballo R, Vazquez-Lopez EM (2009)
Polyhedron 28:3915–3922
11. Jouad EM, Allain M, Khan MA, Bouet GM (2005) Polyhedron
24:327–332
12. Leovac VM, Novakovic SB, Bogdanovic GA, Joksovic MD,
Szecsenyi KM, Cesljevic VI (2007) Polyhedron 26:3783–3792
13. Latheef L, Manoj E, Kurup MRP (2007) Polyhedron 26:4107–
4113
14. Alomar K, Khan MA, Allain M, Bouet G (2009) Polyhedron
28:1273–1280
15. Lobana TS, Khanna S, Castineiras A (2007) Inorg Chem Com-
mun 10:1307–1310
16. Belicchi-Ferrari M, Bisceglie F, Cavalieri C, Pelosi G, Tarasconi
P (2007) Polyhedron 26:3774–3782
17. Lobana TS, Sharma R, Pannu APS, Hundal G, Butcher RJ,
Castineiras A (2007) Polyhedron 26:2621–2628
18. Krishna PM, Reddy KH (2009) Inorg Chim Acta 362:4185–4190
19. Belicchi-Ferrari M, Bisceglie F, Buluggiu E, Pelosi G, Tarasconi
P (2009) Polyhedron 28:1160–1168
20. Lobana TS, Kumari P, Butcher RJ (2008) Inorg Chem Commun
11:11–14
Fig. 9 The B3LYP/6-31G optimized structure of 2
21. Lobana TS, Sharma R, Butcher RJ, Castineiras A, Bermejo E,
Bharatam PV (2006) Inorg Chem 45:1535–1542
22. Lobana TS, Khanna S, Butcher RJ, Hunter AD, Zeller M (2007)
Inorg Chem 46:5826–5828
23. Lobana TS, Sharma R, Butcher RJ (2009) Polyhedron 28:1103–
1110
obtained free of charge on application to The Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK, fax:
?44 1223 336 033, e-mail: deposit@ccdc.cam.ac.uk or
http://www.ccdc.cam.ac.uk.
24. Lobana TS, Khanna S, Hundal G, Butcher RJ, Castineiras A
(2009) Polyhedron 28:3899–3906
Acknowledgments We acknowledge Golestan University (GU) and
Damghan University (DU) for partial support of this study and
Okayama University (OU) for X-ray analysis.
25. Yildiz M, Unver H, Erdener D, Kiraz A, Iskeleli NO (2009) J Mol
Struct 919:227–234
26. Sun Y, Fu S, Zhang J, Wang X, Wang D (2009) Acta Cryst
E65:o237
27. Bourosh PN, Revenko MD, Gdaniec M, Stratulat EF, Simonov
YA (2009) J Struct Chem 50:510513
28. Sheldrick GM (2008) Acta Cryst A64:112–122
29. Farrugia LJ (1997) J Appl Cryst 30:565
30. Handy NC, Murry CV, Amos RD (1993) J Phys Chem 97:4392–
4398
31. Handy NC, Maslen PE, Amos RD, Anderws JS, Murry CV,
Laming G (1992) Chem Phys Lett 197:506–515
32. Stephens PJ, Devlin FJ, Chavalowskyi CF, Frish MJ (1994)
J Phys Chem 98:11623–11627
33. Devlin FJ, Finley JW, Stephens PJ, Frish MJ (1995) J Phys Chem
99:16883–16902
References
1. Lobana TS, Sharma R, Bawa G, Khanna S (2009) Coord Chem
Rev 253:977–1055
2. Dilovic I, Rubcic M, Vrdoljak V, Pavelic SK, Kralj M, Piantanida
I, Cindric M (2008) Bioorg Med Chem 16:5189–5198
3. Bal T, Atasever B, Solakoglu Z, Erdem-Kuruca S, Ulkuseven B
(2007) Eur J Med Chem 42:161–167
4. Khnnan S, Sivagamasundari M, Ramesh R, Liu Y (2008)
J Organomet Chem 693:2251–2257
5. Belicchi-Ferrari M, Bisceglie F, Pelosi G, Pinelli S, Tarasconi P
(2007) Polyhedron 26:5150–5161
34. Frisch MJ et al (1998) GAUSSIAN 98, Revision A.9. Gaussian
Inc., Pittsburgh, PA
35. Wang JG, Jian FF, Ding YF (2008) Acta Cryst E64:o1730
6. Belicchi-Ferrari M, Bisceglie F, Pelosi G, Pinelli S, Tarasconi P
(2008) Polyhedron 27:1361–1367
7. Poyraz M, Sari M, Demirci F, Kosar M, Demirayak S,
Buyukgungor O (2008) Polyhedron 27:2091–2096
123