Salt and co-crystal formation from 6-bromobenzo[d]thiazol-2-amine and different carboxylic acid derivatives

Article abstract of DOI:10.1016/j.molstruc.2012.02.036

Studies concentrating on non-covalent interactions between the organic base of 6-bromobenzo[d]thiazol-2-amine, and carboxylic acid derivatives have led to an increased understanding of the role 6-bromobenzo[d]thiazol-2-amine has in binding with carboxylic

Full text of DOI:10.1016/j.molstruc.2012.02.036

Journal of Molecular Structure 1016 (2012) 55–63
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Salt and co-crystal formation from 6-bromobenzo[d]thiazol-2-amine
and different carboxylic acid derivatives
b
c
b
b
b
Shouwen Jin a, , Pinhui Yan , Daqi Wang , Yijie Xu , Yingyan Jiang , Liangliang Hu
⇑
a Tianmu College of ZheJiang A & F University, Lin’An 311300, PR China
b School of Engineering, ZheJiang A & F University, Lin’An 311300, PR China
c Department of Chemistry, LiaochengUniversity, Liaocheng 252059, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Studies concentrating on non-covalent interactions between the organic base of 6-bromobenzo[d]thia-
zol-2-amine, and carboxylic acid derivatives have led to an increased understanding of the role 6-bro-
mobenzo[d]thiazol-2-amine has in binding with carboxylic acid derivatives. Here anhydrous and
hydrated multicomponent organic acid–base adducts of 6-bromobenzo[d]thiazol-2-amine have been
Received 22 September 2011
Received in revised form 8 February 2012
Accepted 16 February 2012
Available online 24 February 2012
prepared with the carboxylic acids as p-nitrobenzoic acid, fumaric acid, L-tartaric acid, and terephthalic
acid. The four crystalline compounds were characterized by X-ray diffraction analysis, infrared (IR), melt-
ing point (mp), and elemental analysis. All structures adopted hetero R22ð8Þ supramolecular synthons
except the salt 3. Analysis of crystal packing of the compounds under study suggests that there are
NAHꢀ ꢀ ꢀO, OAHꢀ ꢀ ꢀN, and OAHꢀ ꢀ ꢀO hydrogen bonds (charge assisted or neutral) between acid and base
components in the supramolecular assemblies.
Keywords:
Crystal structure
Noncovalent interactions
6-Bromobenzo[d]thiazol-2-amine
Carboxylic acids
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
[12]. Besides the COOH group, the functional groups such as NO2
and OH groups are both good groups in forming organic solid
Intermolecular interactions are responsible for crystal packing
and gaining an understanding of them allows us to comprehend
collective properties and permits the design of new crystals with
specific physical and chemical properties [1]. Intermolecular inter-
through non-covalent interactions [13], thus we select some car-
boxylic acids bearing additional groups such as NO2 and OH. It is
interesting to exploit the robust and directional recognition of car-
boxylic acids with nitrogen containing heterocyclic compounds
[14].
Recently 2-aminoheterocyclic compounds have been reported
to form supramolecular compounds with the carboxylic acid deriv-
atives under the multiple hydrogen bonding action [15,16]. As a
2-aminoheterocyclic compound, 6-bromobenzo[d]thiazol-2-amine
exhibited moderate Anthelmintic activity [17]. Like other 2-amino-
actions, such as hydrogen bonding,
p
ꢀ ꢀ ꢀ
p
stacking, CAHꢀ ꢀ ꢀ
p/
CH2ꢀ ꢀ ꢀ /CH3ꢀ ꢀ ꢀ
p
p
interactions, CAHꢀ ꢀ ꢀO/CH2ꢀ ꢀ ꢀO/CH3ꢀ ꢀ ꢀO interac-
tions, ion pairing, and donor–acceptor interactions are famous for
making aggregates of molecules [2]. Hydrogen bonding is one of
the several types of non-covalent interactions in many organic
and inorganic species, which results in aggregation and controls
self-assembly, in some cases [3–6].
heterocyclic compounds 6-bromobenzo[d]thiazol-2-amine is
a
The design and construction of multicomponent supermole-
cules or supramolecular arrays utilizing non-covalent bonding is
a rapidly developing area in supramolecular synthesis. Thus, the
supramolecular synthesis successfully exploits hydrogen-bonding
and other types of non-covalent interactions, in building supramo-
lecular systems [7]. There are many interesting topological struc-
tures such as one-dimensional (1-D) chains, two-dimensional
(2-D) sheets, and three-dimensional (3-D) networks which have
been constructed through hydrogen bonding interactions [8–10].
The carboxylic acid bears the important hydrogen bonding func-
tional group COOH for crystal engineering [11]. Carboxylic acids
aggregate in the solid state as dimer, catemer, and bridged motifs
potentially tridentate ligand (NSN). Furthermore the halogen (Br)
atoms can generate halogen–halogen bond which has been widely
utilized in crystal engineering [18].
The binary adducts of the carboxylic acids and 6-bro-
mobenzo[d]thiazol-2-amine may show the different hydrogen-
bonding patterns from the three different acceptor atoms. In recent
years, our research group has been involved in the study of organic
acid–base adducts based on carboxylic acids and organic bases. As
an extension of our study of supramolecular assemblies concerning
aromatic N-containing derivatives [19], herein we report the prepa-
ration and structures of four supramolecular compounds assembled
from 6-bromobenzo[d]thiazol-2-amine (L), and the corresponding
carboxylic compounds (Scheme 1), respectively. The four
compounds are (6-bromobenzo[d]thiazol-2-amine): (p-nitroben-
zoic acid) (1) [(L) (Hnba), Hnba = p-nitrobenzoic acid],
⇑
Corresponding author. Tel./fax: +86 571 6374 6755.
E-mail address: jinsw@zafu.edu.cn (S. Jin).
0022-2860/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2012.02.036

56
S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
Br
compound [(L). (Hfum)0.5] (2). Yield: 24 mg, 83.58% (Based on L).
S
N
O
m. p. 232–233 °C. Elemental analysis performed on crystals ex-
posed to the atmosphere: Calcd for C9H7BrN2O2S (287.14): C,
37.61; H, 2.44; N, 9.75; S, 11.14. Found: C, 37.56; H, 2.39; N,
NO2
NH
2
HO
p-nitrobenzoic acid
9.72; S, 11.08. Infrared spectrum (KBr disc, cmꢁ1): 3560s(
m
(OH)),
s(NH)), 3092 m, 2996 m, 2498 m, 1904 m,
(C@O)), 1622 m, 1542 m, 1488s, 1436s, 1296s( (CAO)),
6-bromobenzo[d]thiazol-2-amine
3412s(
1701s(
m
m
as(NH)), 3213s(m
O
m
OH
O
HO
O
1186 m, 1132 m, 1105 m, 1054 m, 1012 m, 936 m, 859 m, 808 m,
738 m, 680 m, 620 m.
OH
HO
OH
HO
O
OH
L-tartaric acid
Scheme 1. Hydrogen bond building blocks discussed in this paper.
O
OH
O
fumaric acid
terephthalic acid
2.2.3. (6-Bromobenzo[d]thiazol-2-amine): (L-tartaric acid): 2H2O
[(HL+). (Htartꢁ) 2H2O] (3)
To an ethanol solution (8 mL) of 6-bromobenzo[d]thiazol-2-
amine (22.9 mg, 0.1 mmol) was added -tartaric acid (15 mg,
L
0.1 mmol). The solution was stirred for 3 min, then the solution
was filtered into a test tube. The solution was left standing at room
temperature for 2 h, light yellow crystals were isolated. The crys-
tals were dried in air to give the title compound [(HL1+).
(Htartꢁ)ꢀ ꢀ ꢀ2H2O] (3). Yield: 32 mg, 77.07% (Based on L). m. p.
188–189 °C. Elemental analysis performed on crystals exposed to
the atmosphere: Calcd for C11H15BrN2O8S (415.22): C, 31.79; H,
3.61; N, 6.74; S, 7.70. Found: C, 31.72; H, 3.58; N, 6.69; S, 7.66.
(6-bromobenzo[d]thiazol-2-amine): (fumaric acid)0.5 (2) [(L).
(H2fum)0.5
,
L
H2fum = fumaric acid], (6-bromobenzo[d]thiazol-2-
amine):
(
-tartaric acid): 2H2O (3) [(HL1+). (Htartꢁ)ꢀ ꢀ ꢀ2H2O,
Htartꢁ = hydrogen tartarate], and (6-bromobenzo[d]thiazol-2-
amine)2: (terephthalic acid) (4) [(L)2 (H2tpa), H2tpa = terephthalic
acid], respectively (Scheme 2).
Infrared spectrum (KBr disc, cmꢁ1): 3645s(
3332s( s(NH)), 3078 m, 1730s( (C@O)), 1631 m, 1598s(mas
(COOꢁ)), 1550 m, 1484 m, 1426 m, 1382s( s(COOꢁ)), 1358 m,
1302s( (CAO)), 1196 m, 1122 m, 1054 m, 940 m, 853 m, 803 m,
732 m, 676 m, 616 m.
m(OH)), 3462s(mas(NH)),
2. Experimental section
m
m
2.1. Materials and physical measurements
m
m
The chemicals and solvents used in this work are of analytical
grade and available commercially and were used without further
purification. The FT-IR spectra were recorded from KBr pellets in
range 4000–400 cmꢁ1 on a Mattson Alpha-Centauri spectrometer.
Microanalytical (C, H, N, S) data were obtained with a Perkin–
Elmer Model 2400II elemental analyzer. Melting points of new
compounds were recorded on an XT-4 thermal apparatus without
correction.
2.2.4. (6-Bromobenzo[d]thiazol-2-amine)2: (terephthalic acid) [(L)2
(H2tpa)] (4)
To a methanol solution (8 mL) of 6-bromobenzo[d]thiazol-2-
amine (22.9 mg, 0.1 mmol) was added terephthalic acid (17 mg,
0.1 mmol) in 10 mL methanol. The solution was stirred for half
an hour, then the solution was filtered into a test tube. The solution
was left standing at room temperature for 27 days, light yellow
block crystals were isolated after slow evaporation of the methanol
solution to ca. 5 mL in air. The crystals were dried in air to give the
title compound [(L)2 (H2tpa)] (4). Yield: 27 mg, 86.49% (Based on
L). m. p. 265–266 °C. Elemental analysis performed on crystals ex-
posed to the atmosphere: Calcd for C22H16Br2N4O4S2 (624.33): C,
42.28; H, 2.56; N, 8.97; S, 10.25; Found: C, 42.24; H, 2.52; N,
2.2. Preparation of the supramolecular compounds 1–4
2.2.1. (6-Bromobenzo[d]thiazol-2-amine): (p-nitrobenzoic acid) [(L)
(Hnba)] (1)
To an ethanol solution (8 mL) of 6-bromobenzo[d]thiazol-2-
amine (22.9 mg, 0.1 mmol) was added p-nitrobenzoic acid
(16.6 mg, 0.1 mmol). The solution was stirred for a few minutes,
then the solution was filtered into a test tube. The solution was left
standing at room temperature for 16 days, light yellow crystals were
isolated after slow evaporation of the ethanol solution to ca. 1 mL in
air. The crystals were collected and dried in air to give the title com-
pound [(L). (Hnba)] (1). Yield: 29 mg, 73.19% (based on L). m. p. 221–
222 °C. Anal. Calcd for C14H10BrN3O4S (396.22): C, 42.40; H, 2.52; N,
10.60; S, 8.07. Found: C, 42.35; H, 2.47; N, 10.54; S, 8.03. Infrared
8.89; S, 10.19. Infrared spectrum (KBr disc, cmꢁ1): 3584s(
3348s( as(NH)), 3242s( s(NH)), 3085 m, 2496 m, 1906 m, 1712s
m(OH)),
m
m
(C@O), 1629 m, 1542 m, 1492 m, 1416 m, 1342 m, 1286s(CAO),
1240 m, 1192 m, 1108 m, 1056 m, 1002 m, 944 m, 878 m, 813 m,
786 m, 722 m, 668 m, 629 m.
spectrum (KBr disc, cmꢁ1): 3616s(
3215s( s(NH)), 3087 m, 2984s, 2508 m, 1896 m, 1668s(
1620 m, 1536s( as(NO2)), 1486 m, 1442 m, 1400 m, 1320s(
NO2)), 1292s( (CAO)), 1246 m, 1202 m, 1162 m, 1094 m, 1006 m,
m
(OH)), 3385s(
m
m
as(NH)),
(C@O)),
as(-
m
2.3. X-ray crystallography and data collection
m
m
m
Suitable crystals were mounted on a glass fiber on a Bruker
SMART 1000 CCD diffractometer operating at 50 kV and 40 mA
952w, 861w, 811 m, 767w, 714 m, 656w, 618w.
using Mo Ka radiation (0.71073 Å). Data collection and reduction
2.2.2. (6-Bromobenzo[d]thiazol-2-amine): (fumaric acid)0.5 [(L).
(H2fum)0.5] (2)
were performed using the SMART and SAINT software [20]. The
structures were solved by direct methods, and the non-hydrogen
atoms were subjected to anisotropic refinement by full-matrix
least squares on F2 using SHELXTL package [21].
Hydrogen atom positions for all of the structures were located
in a difference map and refined independently. Further details of
the structural analysis are summarized in Table 1. Selected bond
lengths and angles for the compounds 1–4 are listed in Table 2,
the relevant hydrogen bond parameters are provided in Table 3.
To an ethanol solution (8 mL) of 6-bromobenzo[d]thiazol-2-
amine (22.9 mg, 0.1 mmol) was added fumaric acid (12 mg,
0.1 mmol) in 5 mL methanol. The solution was stirred for a few
minutes, then the solution was filtered into a test tube. The solu-
tion was left standing at room temperature for 25 days, light yel-
low crystals were isolated after slow evaporation of the solution
to ca. 3 mL in air. The crystals were dried in air to give the title

S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
57
Br
S
N
H
H
N
O
NO2
H
O
1
Br
S
N
H
H
N
O
O
O
H
H
O
N
S
H
N
H
Br
2
Br
H
H
S
H
O
H
N
H
N
O
O
H
O
OH
O
O
H
O
H
H
3
Br
S
N
H
S
N
H
N
N
H
H
O
O
Br
H
O
O
H
4
Scheme 2. The four supramolecular compounds described in this paper, 1–4.
evaporate at ambient conditions to give the final crystalline prod-
ucts. In all of the structures except 3, the heteroaromatic Lewis
base molecules are not protonated therefore 1, 2, and 4 can be clas-
sified as cocrystals, while 3 is an organic salt. The four compounds
are not hygroscopic, and they all crystallized with no solvent mol-
ecules accompanied except salt 3. The molecular structures and
their atom labelling schemes for the four structures are illustrated
in Figs. 1, 3, 5 and 7, respectively. The elemental analysis data for
the four compounds are in good agreement with their composi-
tions. The infrared spectra of the four compounds are consistent
3. Results and discussion
3.1. Preparation and general characterization
6-Bromobenzo[d]thiazol-2-amine has good solubility in com-
mon organic solvents, such as methanol, ethanol, dichloromethane,
chloroform, and acetonitrile. The preparation of compounds 1–4
were carried out with 6-bromobenzo[d]thiazol-2-amine and the
corresponding carboxylic acid derivatives in 1:1 ratio in the corre-
sponding polar hydroalcoholic solution, which was allowed to

58
S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
Table 1
Summary of X-ray crystallographic data for compounds 1, 2, 3, and 4.
1
2
3
4
Formula
Fw
C
14H10BrN3O4S
C9H7BrN2O2S
287.14
C11H15BrN2O8S
415.22
C22H16Br2N4O4S2
624.33
396.22
T (K)
298(2)
298(2)
298(2)
298(2)
Wavelength (Å)
Crystal system
space group
a (Å)
b (Å)
c (Å)
0.71073
Monoclinic
P2(1)
8.5977(8)
4.9726(3)
17.3935(15)
90
0.71073
Monoclinic
P2(1)/c
17.8409(15)
5.1980(4)
11.7711(11)
90
0.71073
Monoclinic
C2
22.777(2)
9.6721(8)
7.1880(6)
90
0.71073
Monoclinic
P2(1)/c
13.9610(13)
3.9045(3)
22.9854(16)
90
a
(°)
b (°)
90.1620(10)
90
743.62(10)
2
1.770
2.928
106.9590(10)
90
1044.15(15)
4
1.827
4.116
97.7670(10)
90
1569.0(2)
4
1.758
2.796
109.717(4)
90
1179.49(16)
2
1.758
3.652
c
(°)
V (Å3)
Z
Dcalcd (Mg/m3)
Absorption coefficient (mmꢁ1
F(000)
)
396
568
840
620
Crystal size (mm3)
h range (°)
0.45 ꢂ 0.21 ꢂ 0.12
2.64–25.04
ꢁ9 ꢃ h ꢃ 10
ꢁ5 ꢃ k ꢃ 5
ꢁ20 ꢃ l ꢃ 16
3734
0.44 ꢂ 0.17 ꢂ 0.10
3.46–25.02
ꢁ14 ꢃ h ꢃ 21
ꢁ5 ꢃ k ꢃ 6
ꢁ14 ꢃ l ꢃ 13
4899
0.35 ꢂ 0.11 ꢂ 0.08
2.29–25.02
ꢁ27 ꢃ h ꢃ 22
ꢁ11 ꢃ k ꢃ 11
ꢁ8 ꢃ l ꢃ 8
4027
0.41 ꢂ 0.36 ꢂ 0.13
2.81–25.01
ꢁ16 ꢃ h ꢃ 15
ꢁ4 ꢃ k ꢃ 4
ꢁ19 ꢃ l ꢃ 27
5416
Limiting indices
Reflections collected
Reflections independent (Rint
)
2421 (0.0710)
0.998
1837 (0.0887)
1.016
2720 (0.0429)
0.907
2078 (0.0822)
1.087
Goodness-of-fit on F2
R indices [I > 2
R indices (all data)
Largest diff. peak and hole (e.Åꢁ3
r
I]
0.0554, 0.1358
0.0682, 0.1428
0.451, ꢁ0.557
0.0454, 0.1103
0.0721, 0.1250
0.621, ꢁ0.423
0.0456, 0.0947
0.0639, 0.1007
0.440, ꢁ0.429
0.0705, 0.1935
0.1072, 0.2150
1.023, ꢁ0.941
)
Table 3
Hydrogen bond distances and angles in studied structures of 1–4.
Table 2
DAHꢀ ꢀ ꢀA
d(DAH)
(Å)
d(Hꢀ ꢀ ꢀA)
d(Dꢀ ꢀ ꢀA)
<(DHA)
(°)
Selected bond lengths (Å) and angles (°) for compounds 1–4.
(Å)
(Å)
1
1
Br(1)AC(5)
S(1)AC(3)
N(1)AC(2)
O(1)AC(8)
C(1)AS(1)AC(3)
N(1)AC(1)AN(2)
N(2)AC(1)AS(1)
1.893(6)
1.764(6)
1.390(8)
1.311(7)
88.7(3)
S(1)AC(1)
N(1)AC(1)
N(2)AC(1)
O(2)AC(8)
C(1)AN(1)AC(2)
N(1)AC(1)AS(1)
O(2)AC(8)AO(1)
1.741(6)
1.313(8)
1.342(8)
1.215(7)
110.3(5)
115.9(4)
123.9(6)
O(1)AH(1)ꢀ ꢀ ꢀN(1)#1
0.82
1.81
2.58
2.35
2.12
2.627(7)
3.106(7)
3.154(8)
2.946(7)
173.9
120.7
154.7
159.7
N(2)AH(2B)ꢀ ꢀ ꢀO(3)#2 0.86
N(2)AH(2B)ꢀ ꢀ ꢀO(4)#3 0.86
N(2)AH(2A)ꢀ ꢀ ꢀO(2)#4 0.86
123.2(6)
120.9(5)
2
O(2)AH(2)ꢀ ꢀ ꢀN(1)#2
0.82
1.82
2.52
2.34
2.15
2.637(4)
2.991(5)
3.155(5)
2.981(5)
170.7
115.0
159.2
161.2
N(2)AH(2B)ꢀ ꢀ ꢀO(1)#3 0.86
N(2)AH(2B)ꢀ ꢀ ꢀO(2)#4 0.86
N(2)AH(2A)ꢀ ꢀ ꢀO(1)#5 0.86
2
Br(1)AC(5)
S(1)AC(1)
N(1)AC(2)
1.904(4)
1.767(4)
1.393(5)
1.223(5)
89.1(2)
S(1)AC(3)
N(1)AC(1)
N(2)AC(1)
O(2)AC(8)
C(1)AN(1)AC(2)
N(1)AC(1)AS(1)
O(1)AC(8)AO(2)
1.745(4)
1.308(5)
1.321(5)
1.305(5)
112.2(3)
114.4(3)
124.8(4)
3
O(1)AC(8)
O(8)AH(8D)ꢀ ꢀ ꢀO(4)#1 0.85
O(8)AH(8C)ꢀ ꢀ ꢀO(4)#2 0.85
O(7)AH(7D)ꢀ ꢀ ꢀO(2)#3 0.85
O(7)AH(7C)ꢀ ꢀ ꢀO(1)#4 0.85
1.96
2.01
1.94
1.90
1.84
1.92
2.64
1.72
2.01
2.37
2.25
2.27
2.801(6)
2.847(6)
2.784(6)
2.745(5)
2.657(5)
2.734(6)
3.252(6)
2.521(5)
2.857(6)
3.049(6)
2.919(7)
2.915(7)
170.3
170.3
174.9
174.9
171.6
174.7
133.0
167.1
170.0
135.7
134.3
131.9
C(3)AS(1)AC(1)
N(1)AC(1)AN(2)
N(2)AC(1)AS(1)
124.5(4)
121.1(3)
O(6)AH(6)ꢀ ꢀ ꢀO(8)
O(5)AH(5)ꢀ ꢀ ꢀO(7)
O(3)AH(3)ꢀ ꢀ ꢀO(2)#3
O(3)AH(3)ꢀ ꢀ ꢀO(1)#3
0.82
0.82
0.82
0.82
3
Br(1)AC(5)
N(1)AC(2)
O(1)AC(8)
O(3)AC(11)
O(5)AC(9)
S(1)AC(1)
C(1)AN(1)AC(2)
N(2)AC(1)AN(1)
N(1)AC(1)AS(1)
O(4)AC(11)AO(3)
1.898(6)
1.395(8)
1.260(6)
1.294(6)
1.416(7)
1.740(6)
115.6(5)
124.9(6)
111.9(4)
124.5(6)
N(1)AC(1)
N(2)AC(1)
O(2)AC(8)
O(4)AC(11)
O(6)AC(10)
S(1)AC(3)
C(1)AS(1)AC(3)
N(2)AC(1)AS(1)
O(2)AC(8)AO(1)
1.319(8)
1.299(7)
1.230(7)
1.221(7)
1.427(6)
1.754(6)
90.3(3)
N(2)AH(2B)ꢀ ꢀ ꢀO(7)#4 0.86
N(2)AH(2A)ꢀ ꢀ ꢀO(5)
N(2)AH(2A)ꢀ ꢀ ꢀO(2)
N(1)AH(1)ꢀ ꢀ ꢀO(2)
0.86
0.86
0.86
123.2(5)
125.6(5)
4
O(1)AH(1)ꢀ ꢀ ꢀN(1)
0.82
1.84
2.07
2.06
2.653(8)
2.918(9)
2.895(9)
169.9
169.5
162.3
N(2)AH(2B)ꢀ ꢀ ꢀO(2)#2 0.86
N(2)AH(2A)ꢀ ꢀ ꢀO(2)
0.86
4
Br(1)AC(5)
N(1)AC(2)
O(1)AC(8)
1.892(8)
1.381(9)
1.300(8)
1.731(7)
110.2(6)
123.7(7)
121.1(6)
N(1)AC(1)
N(2)AC(1)
O(2)AC(8)
S(1)AC(1)
C(3)AS(1)AC(1)
N(1)AC(1)AS(1)
O(2)AC(8)AO(1)
1.320(10)
1.324(10)
1.236(9)
1.750(8)
89.7(3)
Symmetry transformations used to generate equivalent atoms for 1: #1 x, y + 1, z;
#2 ꢁx + 1, y + 1/2, ꢁz; #3 x + 1, y + 1, z; #4 x, y ꢁ 1, z. Symmetry transformations
used to generate equivalent atoms for 2: #2 x, y + 1, z; #3 ꢁx + 1, y ꢁ 1/2, ꢁz + 1/2;
#4 x, ꢁy + 3/2, z ꢁ 1/2; #5 x, y ꢁ 1, z. Symmetry transformations used to generate
equivalent atoms for 3: #1 ꢁx + 1, y, ꢁz + 1; #2 x, y, z + 1; #3 x, y, z ꢁ 1; #4 ꢁx + 3/2,
y + 1/2, ꢁz + 1. Symmetry transformations used to generate equivalent atoms 4: #2
ꢁx, y ꢁ 1/2, ꢁz + 1/2.
S(1)AC(3)
C(1)AN(1)AC(2)
N(1)AC(1)AN(2)
N(2)AC(1)AS(1)
115.2(6)
123.6(7)

S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
59
Fig. 1. Molecular structure of 1 showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
with their chemical formulas determined by elemental analysis
and further confirmed by X-ray diffraction analysis. H atoms con-
nected to O or N atoms were well found from the difference elec-
tron density map.
and the ring N atom with NAO distance of 2.627(7) Å. This kind
of neighboring adducts were connected together via the NAHꢀ ꢀ ꢀO
contact between the nitro group and the NH2 with NAO distance
of 3.154(8) Å, and OAS association between the same O atom of
the nitro group and the ring S atom with OAS separation of
3.311 Å to form a 1D chain running parallel to the a axis direction.
The very strong and broad features at approximately
3700–3200 cmꢁ1 in the IR spectra of the four compounds arise
from OAH or NAH stretching frequencies. Aromatic, and
benzo[d]thiazolic ring stretching and bending are attributed to
the medium intensity bands in the regions of 1500–1630 cmꢁ1
and 600–750 cmꢁ1, respectively. All of the four compounds show
the characteristic bands for COOH, while compound 3 displays
additional strong IR peaks for COOꢁ groups. The presence of two
broad bands at ca. 2500 cmꢁ1 and 1900 cmꢁ1 in compounds 1, 2,
and 4, characteristic of a neutral OAHꢀ ꢀ ꢀN hydrogen-bond interac-
tion, was viewed as evidence for co-crystal formation [22].
Such kind of parallel chains were joined together by the Oꢀ ꢀ ꢀ
p
interactions between the nitro group and the benzene ring of the
p-nitrobenzoic acid with OACg distance of 3.20 Å, and C(car-
bonyl)ꢀ ꢀ ꢀ
p interaction between the carboxyl group and the ben-
zene ring of the p-nitrobenzoic acid with CACg distance of
3.343 Å to form 2D sheet extending on the ab plane (Fig. 2). It is
worthy to note that the p-nitrobenzoic acid molecules at adjacent
chains of the same 2D sheet were not in face to face position, they
slipped some distance along the chain extending direction. Two
such sheets were combined together along the c axis direction
via the intersheet CHAO associations between the benzene CH
and the carbonyl group with CAO distance of 3.224 Å, NAHꢀ ꢀ ꢀO
hydrogen bond between the amine group and the nitro group with
NAO distance of 3.106(7) Å, and OAN contact between the nitro
group with OAN distance of 3.027 Å to form double sheet struc-
ture. Herein the chains at the two different sheets were almost per-
pendicular to each other.
3.2. Structural descriptions
3.2.1. X-ray structure of (6-bromobenzo[d]thiazol-2-amine):
(p-nitrobenzoic acid) [(L) (Hnba)] (1)
The compound 1 of the composition [(L) (Hnba)] was prepared
by reaction equal mol of 6-bromobenzo[d]thiazol-2-amine and p-
nitrobenzoic acid, in which the proton of the p-nitrobenzoic acid
was not transferred to the N atoms at the L molecule. This structure
is not a solvate. In the asymmetric unit of 1 there existed one mol-
ecule of 6-bromobenzo[d]thiazol-2-amine, and one molecule of p-
nitrobenzoic acid, as shown in Fig. 1.
3.2.2. X-ray structure of (6-bromobenzo[d]thiazol-2-amine): (fumaric
acid)0.5 [(L) (H2fum)0.5] (2)
The compound 2 was also prepared by reaction of 6-bro-
mobenzo[d]thiazol-2-amine with fumaric acid in 1:1 ratio, which
crystallizes as monoclinic block crystals in the space group P2(1)/
c. The asymmetric unit of 2 consists of one molecule of 6-bro-
mobenzo[d]thiazol-2-amine, and half a molecule of fumaric acid,
as shown in Fig. 3. Compound 2 is also a cocrystal. The carboxylic
acid groups have C@O and CAO bond distances, indicative of a
protonized character, in which no Hs transfer to the 6-bro-
mobenzo[d]thiazol-2-amine molecules has occurred. The ratio of
CAO(long) to C@O (short) bond distances is 1.067, for the carboxyl
group on C(8). These values are characteristic for unionized COOH
(ionized COOH groups have a lower ratio of about 1.030) [23]. One
fumaric acid and two 6-bromobenzo[d]thiazol-2-amine molecules
produced a heteroadduct via the neutral NAHꢀ ꢀ ꢀO and OAHꢀ ꢀ ꢀN
hydrogen bonds. For the presence of the hydrogen bonds every car-
boxyl moiety of the fumaric acid and the 6-bromobenzo[d]thiazol-
2-amine molecule formed a R22ð8Þ motif. The adjacent heteroad-
ducts were connected together via the Brꢀ ꢀ ꢀBr bonds to form a
The CAO distances of COOH of the p-nitrobenzoic acid are rang-
ing from 1.215(7) to 1.311(7) Å. The difference (
D is 0.096 Å) in
bond distances between O(1)AC(8) (1.311(7) Å) and O(2)AC(8)
(1.215(7) Å) in the carboxyl group in compound 1 is in accordance
with the values in the protonated carboxyl groups. As expected, the
benzo[d]thiazol moiety is planar (the mean deviation from plane is
0.0104 Å). The r.m.s deviation of the benzene ring of the p-nitro-
benzoic acid from the mean plane of the ring is 0.0021 Å, which
forms dihedral angle of 1.7° with the benzo[d]thiazol unit. The car-
boxyl and the nitro groups deviate by 2.2°, and 9.2°, respectively
from the benzene ring of the p-nitrobenzoic acid molecule.
The p-nitrobenzoic acid was bonded to the 6-bro-
mobenzo[d]thiazol-2-amine molecule through one NAHꢀ ꢀ ꢀO, and
one OAHꢀ ꢀ ꢀN hydrogen bonds to form a bicomponent adduct with
graph set R22ð8Þ. The NAHꢀ ꢀ ꢀO hydrogen bond is between the amine
group and the carbonyl group with NAO distance of 2.946(7) Å, the
OAHꢀ ꢀ ꢀN hydrogen bond is between the OH of the carboxyl unit

60
S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
Fig. 2. 2D sheet structure of 1 extending on the ab plane.
Fig. 3. Molecular structure of 2 showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
1D chain running along the a axis direction. In this regard the
Brꢀ ꢀ ꢀBr distance (3.520 Å) is significantly shorter than the docu-
mented data (4.0–4.2 Å) [18].
belonging to adjacent sheets with CAS separation of 3.734 Å) inter-
actions to form 3D ABAB layer network structure. In this regard the
adjacent sheets made an angle of ca 60° with each other. In addi-
tion the third sheet was parallel to the first sheet, but the third
sheet was slipped some distance from the first sheet along the a,
and b axis directions respectively, so did the second sheet and
the fourth sheet.
The 1D chains were combined together by the interchain C(car-
bonyl)ꢀ ꢀ ꢀ
p interaction with CACg distance of 3.276 Å, and O(car-
bonyl)ꢀ ꢀ ꢀC(carbonyl) interaction between the carbonyl group and
the C atom of the carboxyl group with OAC distance of 3.130 Å
to form a 2D corrugated sheet running along the ab plane
(Fig. 4). Such kind of 2D corrugated sheets stacked along the c axis
direction and joined together by the NAHꢀ ꢀ ꢀO (one NH of the
amine group formed a bifurcated NAHꢀ ꢀ ꢀO association with the
carbonyl unit of one carboxyl group, and the OH unit of another
COOH with NAO distances of 2.991(5) Å, and 3.155(5) Å, respec-
tively), and CHAS (between 8-CH of the 6-bromobenzo[d]thiazol-
2-amine and the S atom of 6-bromobenzo[d]thiazol-2-amine
3.2.3. X-ray structure of (6-bromobenzo[d]thiazol-2-amine): (L-
tartaric acid): 2H2O [(HL+) (Htart-) 2H2O] (3)
The compound 3 crystallizes as monoclinic block crystals in the
space group C2. X-ray analysis reveals that the compound consists
of one 6-bromobenzo[d]thiazolium-2-amine cation, one hydrogen
tartrate anion, and two water molecules (Fig. 5). The present inves-
tigation clearly shows that the positive charge (coming from the
Fig. 4. 2D corrugated sheet running along the ab plane.

S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
61
Fig. 5. Molecular structure of 3 showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
carboxylic H of
L-tartaric acid) in the title compound is on the ring
in the 2D sheet were antiparallel to each other, so did the cations.
nitrogen atom not at the extra-ring amine group, forming an ion
pair, which is different from compounds 1, and 2. Here only one
proton of the acid was ionized to exhibit a valence number of
ꢁ1. As shown in Table 2, all the bond angles and bond distances
are in the normal range.
The cations of the second grid layer were located at the centre of
the first grid layer. The 2D sheets were further stacked along the
a axis direction via the OAHꢀ ꢀ ꢀO, and NAHꢀ ꢀ ꢀO interactions to form
3D layer network structure. In this case the third 2D sheet has the
same projection on the bc plane as the first 2D sheet, so does the
second 2D sheet and the fourth 2D sheet.
In the COOH (C(11)AO3AO4) group, two CAO bond lengths are
obviously different between O(3)AC(11) (1.294(6) Å) and
O(4)AC(11) (1.221(7) Å) with the
protonized COOH group character. The relatively larger
D
value of 0.073 Å, indicating
value
3.2.4. X-ray structure of (6-bromobenzo[d]thiazol-2-amine)2:
(terephthalic acid) [(L)2 (H2tpa)] (4)
D
which is expected for neutral CAO and C@O bond distances [24]
is also confirming the reliability of adding H atoms experimentally
by different electron density onto O atoms. But for the COOꢁ group,
two CAO bond lengths (The CAO distances of COOꢁ of the hydro-
Similar to 2, the asymmetric unit of 4 consists of one molecule
of 6-bromobenzo[d]thiazol-2-amine and half a molecule of tere-
phthalic acid, as shown in Fig. 7. The CAO distances of the COOH
of the terephthalic acid are ranging from 1.236(9) to 1.300(8) Å,
which suggest that the carboxyl group is not ionized.
gen tartrate are ranging from 1.230(7) to 1.260(6) Å,
D = 0.030 Å)
are basically not equal with an average value of 1.245(6) Å, which
is shorter than that of the single bond of O(3)AC(11) (1.294(6) Å),
but longer than that of the double bond of O(4)AC(11) (1.221(7) Å)
in the carboxyl group of the hydrogen tartrate. It is clear that the
difference in bond lengths of CAO within the carboxyl group
(0.073 Å) is greatly larger than the one found in the carboxylate
group (0.030 Å), which also confirms the deprotonation of only
one carboxylic H.
There is also not significant conformational difference in the
hydrogen tartrate anion, the characteristic O5AC9AC10AO6 tor-
sion angle being ꢁ60.76(2)°, which compares with the values
[ꢁ63.5 (3), ꢁ65.11(17), and ꢁ70.5(2)°] in the three hydrogen tar-
trate anions reported by Graham Smith [25].
In the compound, there are consistently ionic hydrogen bonds
formed between the NH+ cation and the COꢁ2 anions, which is to
be expected [26]. The anions were arranged in head to tail fashion
along the c axis direction via the OAHꢀ ꢀ ꢀO associations between
the OH of the carboxyl group and the carboxylate to form a 1D
chain. In the chain there are also stitched water molecules through
OAHꢀ ꢀ ꢀO hydrogen bonds in which the water molecule acts both as
the hydrogen bond donor forming hydrogen bond with one O atom
of the carboxylate and acceptor forming hydrogen bond with the
alcohol group of the anion. Such chains were arranged parallelly
at the bc plane and were held together by the cations to form 2D
grid structure (Fig. 6). In the grid there existed the hydrogen-
bonded R21ð5Þ, R12ð6Þ, and R33ð12Þ motifs, respectively. Two adjacent
grids were combined together by the CHAO interactions to form
2D sheet structure. In this case the anions at the two adjacent grids
Two L molecules are bound to one terephthalic acid molecule
through one NAHꢀ ꢀ ꢀO hydrogen bond (N(2)AH(2A)ꢀ ꢀ ꢀO(2)) gener-
ated by the NH2 of L and the carbonyl group with NAO distance of
2.895(9) Å, and one OAHꢀ ꢀ ꢀN hydrogen bond (O(1)AH(1)ꢀ ꢀ ꢀN(1))
between the carboxyl OH and the ring N atom of L with NAO dis-
tance of 2.653(8) Å to generate a heteroadduct with the R22(8)
graph set. In the heteroadduct the two L and one terephthalic acid
molecules are almost in the same plane. Such kind of heteroad-
ducts were joined together via the NAHꢀ ꢀ ꢀO hydrogen bond be-
tween the amino group of L and the carbonyl group belonging to
terephthalic acid with NAO distance of 2.918(9) Å to form a 1D zig-
zag chain running along the c axis direction (Fig. 8). In the chain the
adjacent tricomponent heteroadducts made an angle of ca.130°
with each other, while the third tricomponent heteroadduct was
parallel to the first tricomponent heteroadduct, so did the second
tricomponent heteroadduct and the fourth tricomponent hete-
roadduct. The 1D chains were further stacked along the b axis
direction via the interchain NAHꢀ ꢀ ꢀO hydrogen bond between the
amino group and the carbonyl group with NAO distance of
2.918(9) Å to form 2D corrugated sheet extending parallel to the
bc plane.
4. Conclusions
Four supramolecular compounds with different topologies have
been prepared and structurally characterized. The different hydro-
gen bond interaction modes of the carboxylic acids and the 6-bro-
mobenzo[d]thiazol-2-amine led to
a wide range of different

62
S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
Fig. 6. 2D grid structure of 3 extending at the bc plane.
Fig. 7. Molecular structure of 4 showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
Fig. 8. 1D chain structure of 4 running along the c axis direction.
structures such as 2D double sheet structure, 3D ABAB layer net-
work structure, 3D layer network structure, and 2D corrugated
sheet structure.
Despite variations in molecular shape on the carboxylic acid
derivatives, there all featured strong intermolecular hydrogen
bonds between the carboxylic acid and the 6-bromobenzo[d]thia-
zol-2-amine. In the compounds 1, 2, and 4, the COOH remained
pKa(acid) P 3). While the DPka for 1, 2, and 4 may be out of the
range of salt formation.
This study has demonstrated that the OAHꢀ ꢀ ꢀN/N–Hꢀ ꢀ ꢀO hydro-
gen bond is the primary intermolecular force in a family of struc-
tures containing the OHꢀ ꢀ ꢀ6-bromobenzo[d]thiazol-2-amine
synthons. In addition the nonclassical weak interactions were also
played important role in structure extension. In all of the com-
pounds except 3, the most common hydrogen-bonded hetero
R22ð8Þ graph sets for 2-aminoheterocyclic derivatives have been ob-
served. Salt 3 has the hydrogen-bonded R21ð5Þ, R12ð6Þ, and R33ð12Þ
motifs.
protonated, while in 3, one COOH group of the
deprotonated. This phenomenon may be explained by the fact:
for the carboxylic acids present in 1–4, the -tartaric acid has the
smallest Pka (Pka1) among all of the acids discussed in this manu-
script which may led the Pka (between the L and the carboxylic
acid) to be in the range for salt formation (pKa(base)
L-tartaric acid was
L
D
In conclusion, we have shown that 2D/3D structures can be
constructed by the collective weak interactions such as strong
–

S. Jin et al. / Journal of Molecular Structure 1016 (2012) 55–63
63
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Nos. 841391 for 1, 845147 for 2, 841388 for 3, and 841396 for 4.
Copies of this information may be obtained free of charge from
the +44 (1223)336-033 or Email: deposit@ccdc.cam.ac.uk or
www: http://www.ccdc.cam.ac.uk.
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(Project No.
Y201017321) and the financial support of the Zhejiang A & F Uni-
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