Crystal and Molecular Structures of Five 3D Organic Salts from 2,6-Dimethylaniline and Organic Acids

Article abstract of DOI:10.1007/s10870-018-0760-0

Five crystalline organic acid-base salts [(HL)·(dnsa^?), L = 2,6-dimethylaniline, dnsa^??=?3,5-dinitrosalicylate] (1), [(HL⁺)·(4-Hnpta^?), 4-Hnpta^??=?4-nitrophthalate] (2), [(HL)₂·(nds)·(H

Full text of DOI:10.1007/s10870-018-0760-0

Journal of Chemical Crystallography
https://doi.org/10.1007/s10870-018-0760-0
ORIGINAL PAPER
Crystal and Molecular Structures of Five 3D Organic Salts
from 2,6-Dimethylaniline and Organic Acids
Zuoran Xie1 · Yuan Lu1 · Shouwen Jin1 · Haomiao Ye1 · Zhong Wang1 · Bin Liu1 · Daqi Wang2
Received: 22 November 2016 / Accepted: 11 December 2018
© Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract
Five crystalline organic acid-base salts [(HL)·(dnsa−), L=2,6-dimethylaniline, dnsa− = 3,5-dinitrosalicylate] (1), [(HL+)·(4-
Hnpta−), 4-Hnpta− = 4-nitrophthalate] (2), [(HL)2·(nds)·(H2O)2, nds=1,5-naphthalenedisulfonate] (3), [(HL)·(dnb)·(Hdnb),
dnb=3,5-dinitrobenzoate, Hdnb=3,5-dinitrobenzoic acid] (4) and [(HL)·(dca), dca=dichloroacetate] (5) from 2,6-dimeth-
ylaniline and organic acids were prepared and characterized by XRD analysis, IR, mp and elemental analysis. Com-
pound 1 adopts the triclinic, space group Pī, with a=7.6261(6) Å, b=8.3429(8) Å, c=13.1147(12) Å, α=91.3610(10)º,
β=102.755(2)º, γ=102.597(2)º, V=791.96(12) Å3, Z=2. Compound 2 belongs to the monoclinic, space group P2(1)/c, with
a=14.2552(15) Å, b=8.1436(8) Å, c=14.5708(13) Å, α=90°, β=113.795(2)º, γ=90°, V=1547.7(3) Å3, Z=4. Compound
3 crystallizes in the monoclinic, space group P2(1)/c, with a=8.4784(7) Å, b=17.4798(15) Å, c=9.1119(8) Å, α=90°,
β=99.742(2)º, γ=90°, V=1330.9(2) Å3, Z=2. Compound 4 has orthorhombic, space group Pna2(1), with a=24.5029(19)
Å, b=7.5322(9) Å, c=26.665(2) Å, α=90°, β=90°, γ=90°, V=4921.3(8) Å3, Z=8. Compound 5 crystallizes in the mono-
clinic, space group C2/c, with a=19.8970(17) Å, b=11.1850(11) Å, c=13.1590(12) Å, α=90°, β=123.408(3)º, γ=90°,
V=2444.6(4) Å3, Z=8. For 1 it was the relatively weak phenol that has ionized, different from 2 to 5. All supramolecular
architectures of 1–5 involve N–H⋯O H-bonds as well as CH3⋯O interactions. The other noncovalent interactions (CH⋯O,
CH⋯Cl, O⋯C, O⋯N, O⋯O, Cl⋯Cl, C⋯π, O⋯π, CH3⋯π and π⋯π) in the crystal packing were also ascertained. These
weak interactions combined, all compounds displayed 3D framework structures.
Electronic supplementary material The online version of this
article (https://doi.org/10.1007/s10870-018-0760-0) contains
supplementary material, which is available to authorized users.
Extended author information available on the last page of the article
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1 3

Journal of Chemical Crystallography
Graphical Abstract
In the five prepared supramolecular assemblies there are plenty of weak bonding interactions such as directional H-bonds
of N–H⋯O, O–H⋯O, O–H⋯S, O–H⋯N and noncovalent bonds of CH⋯O, CH3⋯O, CH⋯Cl, O⋯C, O⋯N, O⋯O, Cl–Cl,
C⋯π, O⋯π, CH3⋯π, and aryl⋯aryl interactions. All compounds displayed the 3D framework structures
Keywords Crystal structures · H-bonding · Noncovalent interactions · 2,6-Dimethylaniline · Organic acids
amine derivative, the organic acid–base adducts based on
2,6-dimethylaniline have also been studied [58, 59].
In continuation of our study on organic acid–base
adducts concerning aryl N-containing derivatives [60–65],
herein we report the preparation and structures of five
organic acid–base salts from 2,6-dimethylaniline (L) and
the corresponding organic acids (Scheme 1), respectively.
The five salts are [(HL)·(dnsa−), L = 2,6-dimethylaniline,
dnsa− = 3,5-dinitrosalicylate] (1), [(HL+)·(4-Hnpta−),
4-Hnpta− = 4-nitrophthalate] (2), [(HL)2·(nds)·(H2O)2,
nds=1,5-naphthalenedisulfonate] (3), [(HL)·(dnb)·(Hdnb),
dnb = 3,5-dinitrobenzoate, Hdnb = 3,5-dinitrobenzoic
acid] (4), and [(HL)·(dca), dca = dichloroacetate] (5)
(Scheme 2).
Introduction
Noncovalent interactions of electrostatic forces, H-bonding,
CH⋯π, π⋯π stacking, cation⋯π, anion⋯π and lone pair⋯π
associations, as well as other weak forces play signifi-
cant roles in numerous fields from molecular recognition,
host–guest chemistry, crystal engineering, supramolecular
chemistry, biochemistry, pharmaceutical chemistry, to mate-
rials science [1–16]. In the past few years, great efforts have
been made to elucidate these interactions and their relation-
ship to the final supramolecular structures [17–21].
In the case of pharmaceutical ingredients, solid salts with
such biopharmaceutical properties as solubility, stability
and hygroscopicity have been studied systematically, and
these properties are related to the noncovalent interactions
[22–33]. The organic acids carry the nice donor–acceptor
units for the supramolecular crystal engineering [34–36],
and they aggregate in the solid as dimer, catemer and
bridged modes [37–44]. Except the acidic units, the phenol,
NO2, X and the aryl kernel are all good at numerous nonco-
valent associations, thus the acids with the above units were
selected. It is very critical to study the powerful and direc-
tional recognition from the organic acids and the basic com-
ponents of organic amine and pyridyl derivatives [45–51]. It
is interesting to exploit the robust and directional recognition
of acids with N-containing compounds [47, 48, 50, 52, 53].
Recently aromatic amine derivatives have been reported
to form supramolecular compounds with the acid deriva-
tives under the H-bonding action [54–57]. As a benzene
Experimental Section
Materials and Physical Measurements
The chemicals and solvents in this work are analytical
grade and available commercially and used without fur-
ther purification. FT-IR spectra were recorded from KBr
pellets in 4000–400 cm−1 on a Mattson Alpha-Centauri
spectrometer. Microanalytical (C, H, N, S) data were taken
by a Perkin-Elmer Model 2400II elemental analyzer. Melt-
ing points of the salts were recorded on an XT-4 thermal
apparatus without correction.
1 3

Journal of Chemical Crystallography
NO
Scheme 1 H-bond tectons
2
O N
2
discussed in this paper
O
O
H N
2
HO
OH
O
O N
2
OH
OH
2,6-dimethylaniline
3,5-dinitrosalicylic acid
4-nitrophthalic acid
NO
NO
2
O
HO
OH
O
O
S
S
OH
O
O
HO
O
Cl
2
Cl
dichloro-acetic acid
3,5-dinitrobenzoic acid
1, 5-naphthalenedisulfonic acid
stirred for a few minutes, then the solution was filtered into a
test tube. The solution was left standing at room temperature
for 10 days, colorless block crystals were isolated after slow
evaporation of the methanol solution in air. The crystals were
collected and dried in air to give [(HL+) · (4-Hnpta−)] (2).
(yield: 54 mg, 81.25%). mp 117–118 °C. Elemental analysis:
Calc. for C16H16N2O6 (332.31): C, 57.78; H, 4.81; N, 8.42.
Found: C, 57.69; H, 4.75; N, 8.33. Infrared spectrum (cm−1):
3590s (ν(OH)), 3432s (νas(NH)), 3326s (νs(NH)), 3175m,
3123m, 3084m, 2912m, 2828m, 1680s (ν(C=O)), 1618s
(νas(CO2−)), 1572m, 1528s (νas(NO2)), 1487m, 1445m,
Preparation of the Organic Salts 1–5
(2,6-Dimethylaniline):(3,5-Dinitrosalicylic acid)
[(HL)·(dnsa−)] (1)
A solution of 3,5-dinitrosalicylic acid (45.6 mg, 2.0 mmol)
in methanol (16 ml) was added dropwise to a vigorously
stirred solution of 2,6-dimethylaniline (24.2 mg, 2.0 mmol)
in methanol (5 ml) over a period of 5 min. 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 15 days, colorless block crystals were isolated after slow
evaporation of the methanol solution in air. The crystals
were collected and dried in air to give [(HL)·(dnsa−)] (1).
(yield: 48 mg, 68.71%). mp 140–142 °C. Elemental analy-
sis: Calc. for C15H15N3O7 (349.30): C, 51.53; H, 4.29; N,
12.02. Found: C, 51.42; H, 4.21; N, 11.94. Infrared spectrum
(cm−1): 3666s (ν(OH)), 3442s (multiple, νas(NH)), 3333s
(νs(NH)), 3160w, 3048m, 2978m, 1828w, 1708s (νas(C=O)),
1618m, 1530s (νas(NO2)), 1484w, 1440m, 1399m, 1358m,
1320s (νs(NO2)), 1280s (νs(C–O)), 1238m, 1196m, 1154m,
1112m, 1066m, 1025m, 982m, 940m, 896m, 852m, 808m,
765m, 722m, 678m, 636m, 602m.
−
1406s (νs(CO2 )), 1365m, 1324s (νs(NO2)), 1282s (ν(C–O)),
1236m, 1193m, 1152m, 1109m, 966m, 924m, 882m, 836m,
792m, 749m, 705m, 664m, 621m, 600m.
(2,6-Dimethylaniline)2:(1, 5-Naphthalenedisulfonic
acid):(H2O)2 [(HL)2·(nds)·(H2O)2] (3)
A solution of 1,5-naphthalenedisulfonic acid tetrahydrate
(72 mg, 2.0 mmol) in methanol (30 ml) was added drop-
wise to a vigorously stirred solution of 2,6-dimethylaniline
(24.2 mg, 2.0 mmol) in methanol (5 ml) over a period of
5 min. 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 24 days, colorless
block crystals were isolated after slow evaporation of the
methanol solution in air. The crystals were collected and
dried in air to give [(HL)2 · (nds) · (H2O)2] (3). (yield:
70 mg, 61.76%, based on 1,5-naphthalenedisulfonic acid
tetrahydrate). mp 183–185 °C. Elemental analysis: Calc.
for C26H34N2O8S2 (566.67): C, 55.06; H, 6.00; N, 4.94; S,
(2,6-Dimethylaniline):(4-Nitrophthalic acid) [(HL+) ·
(4-Hnpta−)] (2)
A solution of 4-nitrophthalic acid (42.2 mg, 2.0 mmol)
in methanol (10 ml) was added dropwise to a vigorously
stirred solution of 2,6-dimethylaniline (24.2 mg, 2.0 mmol)
in methanol (5 ml) over a period of 5 min. The solution was
1 3

Journal of Chemical Crystallography
Scheme 2 The five organic acid–base salts 1–5 described in this paper
1 3

Journal of Chemical Crystallography
11.29. Found: C, 55.01; H, 5.92; N, 4.88; S, 11.18. Infra-
red spectrum (cm−1): 3628w(ν(OH)), 3473s (νas(NH)),
3350s (νs(NH)), 3262w, 3144m, 3090m, 1668m, 1620m,
1560m, 1516m, 1470m, 1428m, 1386m, 1344m, 1303mm,
1260m, 1217m, 1175m, 1133m, 1090m, 1049m, 1003m,
960m, 917m, 876m, 835m, 794m, 748m, 706m, 665m,
627m, 608m.
X‑ray Crystallography and Data Collection
Suitable crystals were mounted on a glass fiber at a
Bruker SMART 1000 CCD diffractometer operating at
50 kV and 40 mA using Mo Kα radiation (0.71073 Å).
Data collection and reduction were taken by the SMART
and SAINT software [66]. The structures were solved by
direct methods, and the non-Hs were subjected to aniso-
tropic refinement by full-matrix least squares on F2 by
SHELXTL package [67]. H-atom positions for the five
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 1–5 are listed in Table 2, the relevant H-bond param-
eters in Table 3.
(2,6-Dimethylaniline):(3,5-Dinitrobenzoic acid)2
[(HL)·(dnb)·(Hdnb)] (4)
A solution of 3,5-dinitrobenzoic acid (42.4 mg, 2.0 mmol)
in methanol (12 ml) was added dropwise to a vigor-
ously stirred solution of 2,6-dimethylaniline (24.2 mg,
2.0 mmol) in methanol (5 ml) over a period of 5 min. 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 12 days, colorless block crystals
were isolated after slow evaporation of the methanol solu-
tion in air. The crystals were collected and dried in air
to give [(HL)·(dnb)·(Hdnb)] (4). (yield: 42 mg, 77.00%,
based on 3,5-dinitrobenzoic acid). mp 173–175 °C. Ele-
mental analysis: Calc. for C22H19N5O12 (545.42): C, 48.40;
H, 3.48; N, 12.83. Found: C, 48.31; H, 3.42; N, 12.76.
Infrared spectrum (cm−1): 3470s (multiple, νas(NH)),
3354s (νs(NH)), 3248w, 3162w, 3080m, 2998m, 1694s
(ν(C=O)), 1606s (νas(CO2−)), 1564m, 1522s (νas(NO2)),
Results and Discussion
Preparation and General Characterization
The preparation of 1–5 were carried out with 2,6-dimethy-
laniline and the corresponding acids at 1:1 in the metha-
nolic solution, which was allowed to evaporate at ambient
conditions to give the final crystalline products. In all the
structure, the 2,6-dimethylaniline molecule is protonated
therefore these structure can be classified as organic salts.
The five compounds are not hygroscopic. The molecular
structures and their atom labelling schemes for the five
structures are shown in Fig. 1, Fig. 3, Fig. 5, Fig. 7, and
Fig. 9, respectively. The elemental analysis data for the five
crystalline compounds are in accordance with their compo-
sitions. The infrared spectra of the five compounds fit well
with their chemical formulas determined by elemental analy-
sis and further confirmed by XRD analysis. Hs connected
to O/N atoms were well found from the difference electron
density map. In 2, only one proton of the carboxyl units has
transferred to the N of 2,6-dimethylaniline molecule to get
the corresponding hydrogen carboxylate salt, thus the acid
in 2 presents a valence number of − 1.
−
1452w, 1408s (νs(CO2 )), 1367m, 1325s (νs (NO2)), 1284s
(ν(C–O)), 1240m, 1199m, 1158m, 1115m, 1073m, 1031m,
988m, 955m, 914m, 868m, 824m, 780m, 736m, 694m,
652m, 618m.
(2,6-Dimethylaniline):(Dichloroacetic acid) [(HL)·(dca)] (5)
A solution of dichloroacetic acid (25.8 mg, 2.0 mmol) in
methanol (8 ml) was added dropwise to a vigorously stirred
solution of 2,6-dimethylaniline (24.2 mg, 2.0 mmol) in
methanol (5 ml) over a period of 5 min. The solution was
stirred for a few minutes, then the solution was filtered into
a test tube. The solution was left standing at room tempera-
ture for 8 days, colorless block crystals were isolated after
slow evaporation of the methanol solution in air. The crys-
tals were collected and dried in air to give [(HL)·(dca)] (5).
(yield: 42 mg, 83.96%). mp 147–149 °C. Elemental analysis:
Calc. for C10H13Cl2NO2 (250.11): C, 47.98; H, 5.20; N, 5.60.
Found: C, 47.92; H, 5.11; N, 5.54. Infrared spectrum (cm−1):
3448s (νas(NH)), 3360s (νs(NH)), 3242m, 3160m, 3080m,
The very strong and broad features at 3666–3326 cm−1 in
the IR spectra of the five compounds arise from O–H/N–H
stretching frequencies. Aryl ring stretching and bending are
attributed to the medium intensity bands in 1500–1630 and
600–750 cm−1, respectively. Compound 1 bears character-
istic bands for CO2H only, while the salts 2 and 4 show the
typical bands for both CO2− and CO2H. IR spectroscopy is
also useful for recognizing proton transfer compounds [68,
69]. The most salient feature in the IR spectrum of proton
transfer compounds are the presence of strong asymmetrical/
symmetrical CO2− stretching frequencies at 1598–1618 and
1384–1408 cm−1 respectively except 3.
−
2990m, 2920m, 2832m, 1598s (νas(CO2 )), 1555m, 1513m,
−
1470m, 1426m, 1384s (νs(CO2 )), 1340m, 1298m, 1257m,
1215m, 1174m, 1133m, 1088m, 1046m, 1004m, 962w,
922m, 878w, 836m, 792w, 748m, 706, 660w, 628w, 604w.
1 3

Journal of Chemical Crystallography
Table 1 X-ray crystallographic data for 1–5
1
2
3
4
5
Formula
Fw
C15H15N3O7
349.30
C16H16N2O6
332.31
C26H34N2O8S2
566.67
C22H19N5O12
545.42
C10H13Cl2NO2
250.11
T (K)
Wavelength (Å)
298 (2)
0.71073
298 (2)
0.71073
298 (2)
0.71073
298 (2)
0.71073
298 (2)
0.71073
Crystal system
space group
Triclinic
P-1
Monoclinic
P2(1)/c
Monoclinic
P2(1)/c
Orthorhombic
Pna2(1)
Monoclinic
C2/c
a (Å)
b (Å)
c (Å)
α (°)
7.6261(6)
8.3429(8)
13.1147(12)
91.3610(10)
102.755(2)
102.597(2)
791.96(12)
2
1.465
0.118
364
0.45×0.23×0.12
2.51–25.02
− 9≤h≤5
− 9≤k≤9
− 15≤l≤15
3976
14.2552(15)
8.1436(8)
14.5708(13)
90
113.795(2)
90
1547.7(3)
4
1.426
8.4784(7)
17.4798(15)
9.1119(8)
90
99.742(2)
90
1330.9(2)
2
1.414
24.5029(19)
7.5322(9)
26.665(2)
90
90
90
4921.3(8)
8
1.472
0.122
2256
0.49×0.30×0.17
2.81–25.02
− 29≤h≤29
− 7≤k≤8
− 31≤l≤31
23,166
19.8970(17)
11.1850(11)
13.1590(12)
90
123.408(3)
90
2444.6(4)
8
1.359
β (°)
γ (°)
V, Å3
Z
Dcalcd, Mg/m3
Absorption coefficient, mm−1
F(000)
0.111
696
0.253
600
0.512
1040
Crystal size (mm3)
θ range (°)
0.45×0.26×0.11
2.93–25.02
− 16≤h≤8
− 9≤k≤9
− 16≤l≤17
7641
0.21×0.18×0.16
2.44–25.01
− 9≤h≤10
− 19≤k≤20
− 10≤l≤10
6464
0.49×0.45×0.43
2.40–25.02
− 21≤h≤23
− 13≤k≤13
− 15≤l≤15
6022
Limiting indices
Reflections collected
Reflections independent (Rint
Goodness-of-fit on F2
R indices [I>2σI]
)
2722 (0.0271)
1.057
0.0527, 0.1213
0.1040, 0.1425
0.268, − 0.189
2716 (0.0873)
0.828
0.0571, 0.1244
0.1202, 0.1453
0.246, − 0.184
2328 (0.0806)
0.939
0.0503, 0.1106
0.1147, 0.1366
0.282, − 0.246
8578 (0.0976)
0.922
0.0838, 0.1807
0.1693, 0.2124
0.518, − 0.250
2141 (0.0552)
1.090
0.0673, 0.2031
0.1021, 0.2294
0.754, − 0.368
R indices (all data)
Largest diff. peak and hole, e.Å−3
dnsa− where only the phenol has been deprotonated also
[72–74]. The C–O bond distances O(1)–C(9) (1.220(3) Å)
and O(2)–C(9) (1.299(3) Å) in the CO2H show characteristic
C–O and C=O bond distances which are also confirming
the reliability of adding Hs experimentally by Fourier dif-
ferent electron density onto O atoms as mentioned above
(Table 3). The C–N bond concerning the protonated N was
1.480(3) Å (N(1)–C(1)), similar to the corresponding val-
ues at 2,6-dimethylanilinium chloride monohydrate [58] and
2,6-dimethylanilinium nitrate [75].
Structural Descriptions
X-ray Structure of (2,6-Dimethylaniline):(3,5-Dinitrosalicylic
Acid) [(HL)·(dnsa−)] (1)
The compound 1 of the composition [(HL)·(dnsa−)] was
prepared by reacting equal mol of 2,6-dimethylaniline
and 3,5-dinitrosalicylic acid, in which the phenol H of the
3,5-dinitrosalicylic acid was transferred to the NH2 of the
2,6-dimethylaniline. Thus 1 can be classified as an organic
salt. In the asymmetric unit of 1 there existed one HL, and
one dnsa− (Fig. 1). In this case it is the phenol not the CO2H
that has been ionized which differs from the 3,5-dinitro-
salicylate salts based on bis(1-benzimidazolyl)-3-oxapen-
tane [70] and cytosine [71], but it resembles the filed ones
[72–74]. This phenomenon may be attributed to the steric
effect of this combination, although the Pka of the phenol is
larger than the Pka of the CO2H.
The nitro groups N2–O4–O5 and N3–O6–O7 deviate by
28.3(2) and 7.2(2)° from the mean plane of the phenyl ring
of the anion. The two NO2 intersected at 34.9(2)° to each
other. The CO2H deviated by only 1.6(2)° from the phenyl
ring plane of the 3,5-dinitrosalicylate. The rings C1–C6 and
C10–C15 made dihedral angle of 127.1(2)° to each other.
There exists intramolecular O–H⋯O H-bond with graph
1
set of S1 (6) from the CO2H and the phenolate with O⋯O
separation of 2.498(3) Å, and the O⋯O contact between the
phenolate and the 3-NO2 with O⋯O separation of 2.695(2)
The C-O distance 1.280(3) Å (O(3)–C(11)) was close to
the one in the filed proton transfer compound bearing the
1 3

Journal of Chemical Crystallography
Table 2 Selected bond lengths [Å] and angles [°] for 1–5
with O⋯O distance of 2.925(2) Å to form a tetracompo-
nent aggregate. The tetracomponent aggregates were linked
together by the CH⋯O association from the phenyl CH
of the cation and the carbonyl unit with C⋯O distance of
3.273(2) Å to get 1D chain running along the c axis. The 1D
chains were combined together by the CH3⋯O association
from the CH3 at HL and the 3-NO2 with C⋯O distance of
3.375(2) Å, and C⋯π contact between the π–C of the CO2H
and the phenyl ring of the anion with C⋯Cg separation of
3.299(3) Å to form 2D sheet extending parallel to the ac
plane (Fig. 2). The 2D sheets were further piled along the b
1
N(1)–C(1)
N(3)–C(14)
O(2)–C(9)
1.480(3) N(2)–C(12)
1.457(3) O(1)–C(9)
1.299(3) O(3)–C(11)
1.462(3)
1.220(3)
1.280(3)
O(1)–C(9)–O(2)
120.0(3)
2
3
4
N(1)–C(1)
O(1)–C(9)
O(3)–C(10)
O(1)–C(9)–O(2)
1.473(4) N(2)–C(14)
1.203(4) O(2)–C(9)
1.241(4) O(4)–C(10)
1.468(4)
1.307(4)
1.266(3)
125.8(3)
O(3)–C(10)–O(4)
125.4(3)
+
axis by the N–H⋯O H-bond from the third H of the NH3
and the 5-NO2 with N⋯O distance of 3.148(3) Å, O⋯O
contact between the 5-NO2 and the OH of the CO2H with
O⋯O distance of 2.995(1) Å, and O⋯O contact from the
5-NO2 groups with O⋯O distance of 3.022(2) Å to make
3D network. In this case the O⋯O separations were in the
filed data [78], but the intermolecular O···O separations were
longer than the above mentioned intramolecular one.
N(1)–C(1)
O(2)–S(1)
S(1)–C(11)
O(1)–S(1)–O(3)
1.484(4) O(1)–S(1)
1.455(3) O(3)–S(1)
1.795(3) O(1)–S(1)–O(2)
111.08(16) O(2)–S(1)–O(3)
1.449(2)
1.455(3)
112.96(16)
112.69(16)
N(1)–C(1)
1.497(8) N(2)-C(9)
1.464(11) N(4)–C(22)
1.496(13) N(6)–C(29)
1.466(9) N(8)–C(36)
1.476(12) N(10)–C(43)
1.238(9) O(2)–C(17)
1.212(9) O(8)–C(24)
1.198(12) O(14)–C(31)
1.195(9) O(20)–C(38)
1.466(8)
1.471(9)
1.443(12)
1.535(10)
1.464(13)
1.244(9)
1.275(10)
1.216(11)
1.326(10)
125.5(7)
N(3)–C(20)
N(5)–C(27)
N(7)–C(34)
N(9)–C(41)
O(1)–C(17)
O(7)–C(24)
O(13)–C(31)
O(19)–C(38)
O(1)–C(17)–O(2)
X-ray Structure of (2,6-Dimethylaniline):(4-Nitrophthalic
acid) [(HL+)·(4-Hnpta−)] (2)
The analysis of the XRD data indicated the compound
2 crystallized as monoclinic colorless block crystals in
the space group P2(1)/c with Z = 4. The compound 2 is a
salt with only one CO2H of the 4-nitro-phthalic acid fully
donated its H to the N of the L, which resembled the known
salts [79]. Figure 3 shows the asymmetric unit of the com-
pound 2 that contains one HL and one 4-nitro-hydrogenph-
thalate. In 2, there is an ion pair without solvent molecules,
which agrees well with the micro-analysis results, and thus
124.8(7)
126.6(9)
O(7)–C(24)–O(8)
O(19)–C(38)–O(20) 124.9(7)
O(13)–C(31)–
O(14)
5
Cl(1)–C(10)
Cl(1′)–C(10)
N(1)–C(1)
O(2)–C(9)
1.727(5) Cl(2)–C(10)
1.470(9) Cl(2′)–C(10)
1.462(4) O(1)–C(9)
1.699(5)
1.791(9)
1.209(4)
+
there exist strong electrostatic interactions from the NH3
and the 4-Hnpta−.
1.209(4) O(1)–C(9)–O(2)
125.8(3)
It is clear that the difference in bond lengths of the
C–O at CO2H (0.104 Å) is much greater than the one in
CO2− (0.025 Å). Also the average distance for C–O (1.254(4)
Å) in the CO2− is less than the C–O single bond (1.307(4) Å)
and greater than the C=O double bond (1.203(4) Å) in the
CO2H of the 4-Hnpta−. This verifies the right assignment of
the 4-nitro-hydrogenphthalate monoanion. The N(1)–C(1)
(1.473(4)) was similar to that at 1. The phenyl rings with
C1–C6 and C11–C16 intersected at 8.4(1)° to each other.
The carboxylates O1–C9–O2 and O3–C10–O4 rotated out
of the phenyl plane by 111.8(2) and 139.1(2)°, respectively,
and the two carboxyl moieties intersected at 61.4(2)° with
each other, which is different from the reported adduct of
phthalate [79, 80].
Å. The O⋯O separation at the intramolecular O–H⋯O
H-bond resembled that at 3,5-dimethylpyrazolium 3,5-dini-
trosalicylate and (s)-( )-1-phenylethylaminium 3,5-dinitro-
salicylate [76, 77].
One HL was bonded to one dnsa− by the bifurcated
+
N–H⋯O H-bonds between one H of the NH3 , the 3-NO2,
and the phenolate with N⋯O distances of 2.971(3) and
2.816(3) Å, CH3···O association from the CH3 and the phe-
nolate with C⋯O distance of 3.478(2) Å, and O⋯π associa-
tion between the 3-NO2 and the phenyl ring of the cation
with O⋯Cg separation of 3.178(2) Å to give a bicomponent
adduct. The bicomponent adducts were joined together by
the N–H⋯O H-bond from the second H of the NH3+ and the
carbonyl unit with N⋯O distance of 2.841(3) Å, CH3···O
association between the CH3 and the same carbonyl unit
as in the N–H⋯O H-bond with C⋯O distance of 3.391(2)
Å, and O⋯O contact between the O at the OH in the CO2H
One cation was bonded to one anion by the N–H⋯O
H-bond from one H of the NH3+ and the CO2− with N⋯O
distance of 2.860(3) Å to form a bicomponent adduct. The
bicomponent adducts were linked together by the N–H⋯O
+
hydrogen bond from the second H of the NH3 and the
1 3

Journal of Chemical Crystallography
Table 3 The hydrogen bonding
geometry (Ǻ, º) in 1–5
D–H⋯A
d(D–H) [Å]
d(H⋯A) [Å]
d(D⋯A) [Å]
<(DHA)[°]
1
O(2)–H(2)⋯O(3)
N(1)–H(1C)⋯O(4)
N(1)–H(1C)⋯O(3)
N(1)–H(1B)⋯O(1)#1
N(1)–H(1A)⋯O(7)#2
2
O(2)–H(2)⋯O(4)#1
N(1)–H(1C)⋯O(3)#2
N(1)–H(1B)⋯O(4)
N(1)–H(1B)⋯O(1)#3
N(1)–H(1A)⋯O(3)#1
3
0.82
0.89
0.89
0.89
0.89
1.74
2.45
1.94
1.95
2.43
2.498(3)
2.971(3)
2.816(3)
2.841(3)
3.148(3)
154.0
117.8
166.9
177.7
138.5
0.82
0.89
0.89
0.89
0.89
1.71
1.89
2.56
2.09
2.11
2.495(3)
2.775(4)
3.077(4)
2.869(3)
2.860(3)
158.3
176.2
117.6
145.4
141.8
O(4)–H(4D)⋯S(1)#2
O(4)–H(4D)⋯O(3)#2
O(4)–H(4C)⋯O(3)
N(1)–H(1C)⋯O(1)#3
N(1)–H(1B)⋯O(2)
N(1)–H(1A)⋯O(4)#4
4
O(20)–H(20)⋯O(1)#1
O(8)–H(8)⋯N(8)#2
O(8)–H(8)⋯O(18)#2
N(2)–H(2C)⋯O(2)#3
N(2)–H(2B)⋯O(17)
N(2)–H(2A)⋯O(19)#4
N(1)–H(1C)⋯O(2)
N(1)–H(1B)⋯O(7)
N(1)–H(1A)⋯O(17)
5
0.85
0.85
0.85
0.89
0.89
0.89
2.94
2.20
2.00
2.04
1.93
1.89
3.766(3)
3.034(4)
2.837(3)
2.840(4)
2.793(4)
2.758(4)
163.1
168.4
168.3
148.9
163.5
165.5
0.82
0.82
0.82
0.89
0.89
0.89
0.89
0.89
0.89
1.70
2.66
1.68
1.97
2.06
2.06
2.06
2.05
1.94
2.505(8)
3.409(10)
2.491(8)
2.855(8)
2.827(7)
2.893(7)
2.833(7)
2.885(7)
2.829(8)
165.3
152.1
171.7
176.4
144.1
155.1
144.4
156.5
175.8
N(1)–H(1C)⋯O(1)#1
N(1)–H(1B)⋯O(1)#2
N(1)–H(1B)⋯O(2)#2
N(1)–H(1A)⋯O(2)#3
0.89
0.89
0.89
0.89
1.86
2.56
2.27
1.88
2.729(4)
3.204(4)
2.978(4)
2.715(4)
164.6
130.0
136.7
155.4
Symmetry codes for 1: #1 − x, − y, − z; #2 − x+1, − y+1, − z. Symmetry codes for 2: #1 − x+2,
y+1/2, − z+1/2; #2 x, − y+3/2, z+1/2; #3 − x+2, y − 1/2, − z+1/2. Symmetry codes for 3: #2 x,
− y+3/2, z+1/2; #3 − x+1, − y+1, − z; #4 − x+1, − y+1, − z+1. Symmetry codes for 4: #1 x+1/2,
− y+1/2, z; #2 x, y+1, z; #3 x, y − 1, z; #4 x − 1/2, − y+1/2, z. Symmetry codes for 5: #1 − x+1/2,
y− +1/2, − z; #2 x − 1/2, y+1/2, z; #3 − x+1/2, y+1/2, − z+1/2
carbonyl of the CO2H with N⋯O distance of 2.869(3)
Å, and CH3⋯O association from the CH3 of HL and the
C=O of the CO2H with C⋯O distance of 3.232(2) Å to
get 1D chain. Two 1D chains were combined together by
the N–H⋯O H-bond of 3.077(4) Å from the second H of
together by the N–H⋯O H-bond from the third H of the
+
−
NH3 and the CO2 with N–O distance of 2.775(4) Å,
aromatic⋯aromatic association between the phenyl ring
of the cation and the aryl ring of the anion with Cg⋯Cg
distance of 3.384(2) Å, and O⋯π contact from the NO2
and the phenyl ring of the cation with O⋯Cg distance of
3.152(2) Å to form 2D sheet extending parallel to the bc
plane (Fig. 4). The 2D sheets were further packed along
the a axis by the CH⋯O contact from the phenyl CH of
the cation and the NO2 with C⋯O separation of 3.500(2)
Å to get 3D network.
+
the NH3 and the CO2−, O–H⋯O hydrogen bond of the
CO2H⋯CO2− with O⋯O distance of 2.495(3) Å, CH3⋯O
−
association from the CH3 and the CO2 with C⋯O dis-
tance of 3.557(2) Å, and CH3⋯O contact from the CH3
and the OH of the CO2H with C⋯O distance of 3.241(2) Å
to build a double chain. The double chains were connected
1 3

Journal of Chemical Crystallography
five-component adduct there found an inversion centre that is
situated at the centre of the C10–C10A bond. Herein the cat-
ion associated with the anion by the N–H⋯O hydrogen bond
from one H of the NH3+ and one O of the SO3− with N⋯O
distance of 2.793(4) Å, and CH3⋯O association between
the CH3 and the same O of the SO3− with C⋯O distance of
3.483(2) Å. The water molecule associated with the SO3− by
the O–H⋯O H-bond from the second O of the SO3− with
O⋯O distance of 3.034(4) Å, and O–H⋯S H-bond from the
S of the SO3− with O⋯S distance of 3.766(3) Å. The five-
component adducts were linked together by the N–H⋯O
H-bond between the second H of the NH3+ and one O of the
SO3− with N⋯O distance of 2.840(4) Å, CH⋯O association
from the naphthalene CH and the SO3− with C⋯O distance
Fig. 1 Molecular structure of 1 showing the atomic numbering
scheme. Displacement ellipsoids are drawn at the 30% probability
level
X-ray Structure
of (2,6-Dimethylaniline)2:(1,5-Naphthalenedisulfonic
acid):(H2O)2 [(HL)2·(nds)·(H2O)2] (3)
Cocrystallization of 2,6-dimethylaniline and naphthalene-
1,5-disulfonic acid in 1:1 gave single crystals suitable for
X-ray diffraction, but the crystal structure determination
(Table 1) revealed that 2,6-dimethylaniline and naphthalene-
1,5-disulfonic acid are in a 2:1 ratio. The crystal structure of
3 consists of one HL, half a dianion of naphthalene-1,5-di-
sulfonate, and one water molecule in the asymmetric unit
(Fig. 5). Salt 3 crystallizes in the monoclinic space group
P2(1)/c. The 2,6-dimethylaniline is protonated at the NH2
also. The C–N bond length concerning the NH3+ in HL was
1.484(4) Å for N(1)–C(1), which is like the correspond-
ing bond lengths at 1 and 2. The S–O bond lengths in the
SO3− range from 1.449(2) Å to 1.455(3) Å (Δ=0.006 Å),
which are close to the corresponding S–O bonds at the
SO3− [81].
Two cations, two water molecules and one dian-
ion produce a five-component adduct exhibiting the
Fig. 3 Molecular structure of 2 showing the atomic numbering
scheme. Displacement ellipsoids are drawn at the 30% probability
level
2
1
R1 (3) and R2 (7) rings denoted by Bernstein [82], at the
Fig. 2 2D sheet structure of 1
extending at the ac plane
1 3

Journal of Chemical Crystallography
Fig. 4 2D sheet structure of
2 extending parallel to the bc
plane
of 3.468(4) Å, and CH3⋯O association between the CH3
and the O of the SO3− with C⋯O distance of 3.405(2) Å to
give 1D chain running along the a axis. The 1D chains were
connected together by the N–H⋯O H-bond from the third
H of the NH3+ and the H2O with N⋯O distance of 2.758(4)
Å, O–H···O H-bond between the water and the SO3− with
O⋯O distance of 2.837(3) Å, and CH3⋯π contact from the
CH3 and the phenyl ring of the cation with C⋯Cg distance
of 3.666(3) Å to get 2D sheet (Fig. 6) extending at the direc-
tion that made ca. 60° with the ab plane. The five-compo-
nent adducts at the neighboring chains were rotated ca. 90°
from each other. Along the direction that was perpendicu-
lar with its extending direction the 2D sheets were further
X-ray Structure of (2,6-Dimethylaniline):(3,5-Dinitrobenzoic
Acid) [(HL)·(dnb)·(Hdnb)] (4)
Salt 4 crystallizes as orthorhombic pale yellow crystals in
the space group Pna2(1). The asymmetric unit of 4 consists
of two cations of 2,6-dimethylaniline, two 3,5-dinitroben-
zoate anions, and two 3,5-dinitrobenzoic acids, as depicted
in Fig. 7. This is a salt where the CO2H of one 3,5-dini-
trobenzoic acids is ionized by H transfer to the N of the
2,6-dimethylaniline, which is also confirmed by the bond
distances of O(1)–C(17) (1.238(9) Å), O(2)–C(17) (1.244(9)
Å), O(13)–C(31) (1.198(12) Å) and O(14)–C(31) (1.216(11)
Å) for the CO2− (Table 2). The differences (Δ=0.006 and
0.018 Å) in bond distances between the pair of bonds in
+
piled by the N–H⋯O H-bond between the NH3 and the
−
H2O with N–O distance of 2.758(4) Å, and O–H···O H-bond
of 2.837(3) Å from the H2O and the SO3− to get 3D network.
There also found intersheet CH3⋯π contact from the CH3
and the phenyl ring of the cation with C⋯Cg distance of
3.666(3) Å.
the CO2 agreed well with the deprotonated CO2H. The
O(7)–C(24) (1.212(9) Å), O(8)–C(24) (1.275(10) Å),
O(19)–C(38) (1.195(9) Å) and O(20)–C(38) (1.326(10) Å)
distances are for CO2H. The N(1)–C(1) (1.497(8) Å) and
N(2)–C(9) (1.466(8) Å) ones were comparable to the cor-
responding bonds at 1–3.
One cation was bonded to an anion by a N–H···O H-bond
between one H of the NH3+ and the CO2− with N⋯O dis-
tance of 2.833(7) Å, and a 3,5-dinitrobenzoic acid by the
N–H⋯O H-bond from the second H of NH3+ and the C=O
of the CO2H with N⋯O distance of 2.885(7) Å to get a tri-
component adduct (A) In the tricomponent adduct A there
existed the O⋯π association from the NO2 of the anion and
the phenyl ring of the 3,5-dinitrobenzoic acid with O⋯Cg
distance of 2.966(2) Å and O⋯N contact from the NO2
groups with O⋯N distance of 3.024(2) Å. An anion was
bonded to the other cation by a N–H⋯O H-bond from one
H of the NH3+ and the NO2 with N⋯O distance of 2.827(7)
Å, and a 3,5-dinitrobenzoic acid by the N–H⋯O hydrogen
bond from the second H of NH3+ and the C=O of the CO2H
with N⋯O distance of 2.893(7) Å to form a tricomponent
adduct (B) In the tricomponent adduct B there was an O⋯π
contact from the NO2 of the anion and the phenyl ring of
the 3,5-dinitrobenzoic acid with O⋯Cg distance of 2.926(2)
Å and O⋯N contact between the nitro groups with O⋯N
Fig. 5 Molecular structure of 3 showing the atomic numbering
scheme. Displacement ellipsoids are drawn at the 30% probability
level
1 3

Journal of Chemical Crystallography
Fig. 6 2D sheet structure of 3
extending at the direction that
made an angle of ca. 60° with
the ab plane
distance of 3.052(2) Å. The tricomponent adducts A and
B were linked together by the N–H⋯O H-bond from the
+
second H of NH3 at the tricomponent adduct A and the
NO2 of the anion at the tricomponent adduct B with N⋯O
distance of 2.893(7) Å, N–H⋯O H-bond between the third
+
−
H of NH3 at the tricomponent adduct B and the CO2 at
the tricomponent adduct A with N⋯O distance of 2.855(8)
Å, CH3⋯O contact between the CH3 and the OH of the
3,5-dinitrobenzoic acid with C⋯O separation of 3.362(1)
Å, O⋯π association from the NO2 and the phenyl ring of
the cation with O···Cg distance of 3.103(1) Å, and aryl⋯aryl
association between the phenyl ring of the cation and the
phenyl ring of the anion with Cg⋯Cg distance of 3.336(2) Å
to get a six-component aggregate. The six-component aggre-
gates were linked together by the N–H⋯O H-bond from the
+
second H of NH3 at the tricomponent adduct B and the
Fig. 7 Molecular structure of 4 (for the crowdedness of the structure
the atom-numbering was not labeled). Displacement ellipsoids are
drawn at the 30% probability level
CO2− at the tricomponent adduct A with N⋯O distance of
3.007(2) Å, N–H⋯O hydrogen bond from the third H of
1 3

Journal of Chemical Crystallography
NH3+ at the tricomponent adduct A and the NO2 of the anion
at the tricomponent adduct B with N⋯O distance of 2.827(7)
Å, O–H⋯O H-bond of the CO2H⋯CO2− with O⋯O distance
of 2.505(8) Å, CH3⋯O association from CH3 and the OH of
the CO2H with C⋯O distance of 3.343(1) Å, N⋯O contact
between the nitro groups with N⋯O distance of 3.034(2)
Å, aryl⋯aryl association from the phenyl ring of the cation
and the phenyl ring of the anion with Cg⋯Cg distance of
3.382(2) Å, and O⋯π contact from the CO2− and the phenyl
core of the cation with O⋯Cg distance of 3.113(2) Å to
get 1D chain running along the b axis. The 1D chains were
combined together by the CH⋯O association from the phe-
nyl CH of the 3,5-dinitrobenzoic acid at the tricomponent
adduct B and the nitro unit of the 3,5-dinitrobenzoic acid at
the tricomponent adduct A with C⋯O distance of 3.578(2) Å
to give 2D sheet extending parallel to the ab plane (Fig. 8).
In the c-axis the 2D sheets were further packed by the
CH⋯O contact from the 4-CH of the cation and the nitro
group with C⋯O distance of 3.380(3) Å, CH3⋯O contact
of 3.511(2) Å from CH3 of the cation and the nitro group,
O⋯O contacts between the nitro groups with O⋯O distances
of 2.873(2)–2.927(2) Å, and O⋯C association from the NO2
and the C of the CO2− with O⋯C separation of 2.994(2) Å to
get 3D ABAB layer network. Herein the corresponding com-
ponents at the adjacent sheets made ca. 60° to each other.
The corresponding components at the first sheet were paral-
lel to the corresponding components at the third sheet, so did
the corresponding ones at the second and the fourth sheet.
X-ray Structure of (2,6-Dimethylaniline):(Dichloroacetic
acid) [(HL)·(dca)] (5)
Compound 5 with the composition [(HL)·(dca)] prepared by
reacting equal mol of 2,6-dimethylaniline and dichloroacetic
acid crystallizes as monoclinic colorless crystals in the space
group C2/c. The asymmetric unit of 5 consists of one HL
and one dca (Fig. 9). The H and Cl atoms at the Cl2CH were
all disordered over two sites with equal occupancy for each
atom. The molecular composition of 5 was the same as the
crystal structure of diisopropylaminium dichloroacetate [83]
with the HL substituted of diisopropylaminium.
Compound 5 is classified as a salt in which CO2H of the
dichloroacetic acid is absolutely ionized by H transfer to
the NH2 of the 2,6-dimethylaniline, which is also supported
by the equal C–O bond lengths (1.209(4) Å) at C9–O1–O2.
Here the two C–O bonds were the same indicating the equal
Fig. 8 2D sheet structure of 4 extending parallel to the ab plane
1 3

Journal of Chemical Crystallography
of 3.416(2) Å to get 1D chain running along the c axis. The
1D chains were combined together by the CH⋯Cl contact
from the phenyl CH of the cation and the Cl at the anion
with C⋯Cl distance of 3.781(3) Å to form 2D sheet extend-
ing parallel to the bc plane (Fig. 10). At the a axis the 2D
sheets were further piled by the Cl⋯Cl bonds with Cl⋯Cl
separation of 3.206(2) Å to get 3D network.
Conclusion
Five organic acid–base crystals have been prepared and their
crystal structures determined. The different H-bond interac-
tion modes of the acids and the 2,6-dimethylaniline lead
to different structures of 3D network and 3D ABAB layer
structure.
Fig. 9 Molecular structure of 5 showing the atomic numbering
scheme. Displacement ellipsoids are drawn at the 30% probability
level
distribution of the negative charge on both O. The C–N bond
(N(1)–C(1), 1.462(4) Å) is similar to the corresponding C–N
bonds at 1–4.
All of the organic acid–base adducts involve H-transfer
from the acidic units to the NH2 of the 2,6-dimethylaniline
except the remarkable phenolate case to form a monoca-
tion. This study has demonstrated that the N–H⋯O H-bonds
are the primary intermolecular forces in a set of structures
containing the OH-2,6-dimethylaniline synthons. Except the
classical H-bonds, the secondary propagating interactions
also made critical contribution to the structure extension.
The five salts all possess CH3⋯O associations, 1, 2 and 3
have the CH⋯O association. O⋯O contacts were found at 1
and 4. Salt 1 has the C⋯π contact, 4 has the O⋯C and O⋯N
associations. There are also aromatic⋯aromatic contacts in
2 and 4. The O⋯π interactions were found in 1, 2 and 4, 3
possesses additional CH3⋯π interaction. Salt 5 bears the
CH⋯Cl and Cl⋯Cl non-covalent bonds. In conclusion, we
have shown that 3D structures can be made by the synergic
One cation was bonded to one anion by the bifurcated
N–H⋯O H-bonds from one H of the NH3+ and both O of
the CO2− with N⋯O distances of 2.978(4)–3.204(4) Å, and
the CH3···O association between the CH3 of HL and the
CO2− with C⋯O distance of 3.434(2) Å to get a bicompo-
nent adduct. Two bicomponent adducts were held together
+
by the N–H⋯O H-bonds from the second H of the NH3
−
and the CO2 with N⋯O distance of 2.729(4) Å to get a
2
1
2
tetracomponent aggregate with R1 (4), R2 (7) and R4 (8)
rings. The tetracomponent aggregates were linked together
by the N–H⋯O H-bonds from the third H of the NH3+ and
−
the CO2 with N–O distance of 2.715(4) Å, and CH3–O
association from the CH3 and the CO2− with C⋯O distance
Fig. 10 2D sheet structure of
5 extending parallel to the bc
plane
1 3

Journal of Chemical Crystallography
27. Sanphui P, Devi VK, Clara D, Malviya N, Ganguly S, Desiraju
GR (2015) Mol Pharm 12:1615
effects of classical H-bonds and other noncovalent contacts
from discrete components.
28. Gu JK, Hill CL, Hu CW (2015) Cryst Growth Des 15:3707
29. Schultheiss N, Lorimer K, Wolfe S, Desper J (2010) CrystEng-
Comm 12:742
30. Chow K, Tong HHY, Lum S, Chow AHL (2008) J Pharm Sci
97:2855
Supporting Information Available
31. Childs SL, Zaworotko MJ (2009) Cryst Growth Des 9:4208
32. Rager T, Hilfiker R (2010) Cryst Growth Des 10:3237
33. Zheng SL, Chen JM, Zhang WX, Lu TB (2011) Cryst Growth Des
11:466
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic data center,
CCDC Nos. 1056246 for 1, 1055981 for 2, 1055982 for 3,
1450208 for 4 and 1447998 for 5. 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.
34. Tothadi S, Sanphui P, Desiraju GR (2014) Cryst Growth Des
14:5293
35. Patra R, Titi HM, Goldberg I (2013) Cryst Growth Des 13:1342
36. Aakeröy CB, Schultheiss NC, Rajbanshi A, Desper J, Moore C
(2009) Cryst Growth Des 9:432
37. Gavezzotti A, Presti LL (2015) Cryst Growth Des 15:3792
38. Das D, Jetti RKR, Boese R, Desiraju GR (2003) Cryst Growth
Des 3:675
Acknowledgements This research was supported by the Open Fund of
Zhejiang Provincial Top Key Discipline of Forestry Engineering under
Grant No. 2014LYGCZ017.
39. Beyer T, Price SL (2000) J Phys Chem B 104:2647
40. Kuduva SS, Craig DC, Nangia A, Desiraju GR (1999) J Am Chem
Soc 121:1936
41. Kolotuchin SV, Fenlon EE, Wilson SR, Loweth CJ, Zimmerman
SC (1995) Angew Chem Int Ed Engl 34:2654
42. Sanphui P, Bolla G, Das U, Mukherjee AK, Nangia A (2013)
CrystEngComm 15:34
References
43. Hursthouse MB, Montis R, Tizzard GJ (2011) CrystEngComm
13:3390
1. Metrangolo P, Neukirch H, Pilati T, Resnatti G (2005) ACC Chem
Res 38:386
44. Das D, Desiraju GR (2006) CrystEngComm 8:674
45. Akiri K, Cherukuvada S, Rana S, Nangia A (2012) Cryst Growth
Des 12:4567
2. Britz DA, Khlobystov AN (2006) Chem Soc Rev 35:637
3. Moulton B, Zaworotko MJ (2001) Chem Rev 101:1629
4. Steiner T (2002) Angew Chem Int Ed 41:48
5. Kinbara K, Hashimoto Y, Sukegawa M, Nohira H, Saigo K (1996)
J Am Chem Soc 118:3441
46. Thanigaimani K, Khalib NC, Temel E, Arshad S, Razak IA (2015)
J Mol Struct 1099:246
47. Men YB, Sun JL, Huang ZT, Zheng QY (2009) CrystEngComm
11:978
6. Soldatov DV, Moudrakovski IL, Grachev EV, Ripmeester JA
(2006) J Am Chem Soc 128:6737
48. Highfill ML, Chandrasekaran A, Lynch DE, Hamilton DG (2002)
Cryst Growth Des 2:15
7. Seaton CC, Parkin A, Wilson CC, Bladen N (2009) Cryst Growth
Des 9:47
49. Lou BY, Perumalla SR, Sun CQC (2015) J Mol Struct 1099:516
50. Nichol GS, Clegg W (2009) Cryst Growth Des 9:1844
51. Haynes DA, Pietersen LK (2008) CrystEngComm 10:518
52. Vishweshwar P, Nangia A, Lynch VM (2002) J Org Chem 67:556
53. MacDonald JC, Dorrestein PC, Pilley MM (2001) Cryst Growth
Des 1:29
8. Bazuin CG, Brandys FA (1992) Chem Mater 4:970
9. Desiraju GR, Steiner T (2001) The weak hydrogen bond in struc-
tural chemistry and biology. Oxford University Press, Oxford
10. Atwood JL, Steed JW (2004) Encyclopedia of supramolecular
chemistry. Marcel Dekker, New York
11. Steed JW, Atwood JL (2009) Supramolecular Chemistry, 2nd edn.
Wiley, Chichester
54. Padmavathy R, Karthikeyan N, Sathya D, Jagan R, Kumar RM,
Sivakumar K (2016) RSC Adv 6:68468
12. MacDonald JC, Whitesides GM (1994) Chem Rev 94:2383
13. Mu Z, Shu L, Fuchs H, Mayor M, Chi L (2008) J Am Chem Soc
130:10840
55. Wu DH, Ge JZ, Cai HL, Zhang W, Xiong RG (2011) CrystEng-
Comm 13:319
56. Jones CL, Wilson CC, Thomas LH (2014) CrystEngComm
16:5849
14. Desiraju GR (2011) Angew Chem Int Ed Engl 50:52
15. Wang ZQ, Wang LY, Zhang X, Shen JC, Denzinger S, Ringsdorf
H (1997) Macromol Chem Phys 198:573
57. Sivakumar PK, Kumar MK, Kumar RM, Chakkaravarthi G,
Kanagadurai R (2015) Acta Cryst E71:o163
16. Arunan E, Desiraju GR, Klein RA, Sadlej J, Scheiner S, Alkorta
I, Clary DC, Crabtree RH, Dhannenberg JJ, Hobza P, Kjaergaard
HG, Legon AC, Mennucci B, Nesbitt DJ (2011) Pure Appl Chem
83:1619
58. Smirani W, Amri O, Rzaigui M (2008) Acta Cryst E64:o2463
59. Tang JJ, Chen J, Wang JT, Lu AH, Chen YS (2008) Acta Cryst
E64:o244
60. Jin SW, Zhang WB, Wang DQ, Gao HF, Zhou JZ, Chen RP, Xu
XL (2010) J Chem Crystallogr 40:87
17. Görbitz CH, Nilsen M, Szeto K, Tangen LW (2005) Chem Com-
mun 34:4288
61. Jin SW, Wang DQ, Jin ZJ, Wang LQ (2009) Polish J Chem
83:1937
18. Du M, Zhang ZH, Guo W, Fu XJ (2009) Cryst Growth Des 9:1655
19. Kodama K, Kobayashi Y, Saigo K (2007) Cryst Growth Des 7:935
20. Braga D, Brammer L, Champness NR (2005) CrystEngComm 7:1
21. Biradha K (2003) CrystEngComm 5:374
62. Jin SW, Zhang WB, Liu L, Gao HF, Wang DQ, Chen RP, Xu XL
(2010) J Mol Struct 975:128
63. Jin SW, Zhang WB, Liu L, Wang DQ, He HD, Shi T, Lin F (2011)
J Mol Struct 991:1
22. Yao J, Chen JM, Xu YB, Lu TB (2014) Cryst Growth Des 14:5019
23. Chen JM, Li S, Lu TB (2014) Cryst Growth Des 14:6399
24. Wang ZZ, Chen JM, Lu TB (2012) Cryst Growth Des 12:4562
25. Gould PJ (1986) Int J Pharm 33:201
64. Jin SW, Liu L, Wang DQ, Guo JZ (2011) J Mol Struct 1005:59
65. Jin SW, Wang DQ, Wang XL, Guo M, Zhao QJ (2008) J Inorg
Organomet Polym 18:300
26. Geng N, Chen JM, Li ZJ, Jiang L, Lu TB (2013) Cryst Growth
Des 13:3546
66. Bruker (2004) SMART and SAINT. Bruker AXS, Madison
1 3

Journal of Chemical Crystallography
67. Sheldrick GM (2000) SHELXTL, Structure Determination Soft-
ware Suite, version 6.14. Bruker AXS, Madison
79. Glidewell C, Low JN, Skakle JMS, Wardell JL (2005) Acta Cryst
C61:o276
68. Lynch DE, Thomas LC, Smith G, Byriel KA, Kennard CHL
(1998) Aust J Chem 51:867
80. Dale SH, Elsegood MRJ, Hemmings M, Wilkinson AL (2004)
CrystEngComm 6:207
69. Smith G, White JM (2001) Aust J Chem 54:97
70. Jin SW, Guo M, Wang DQ (2012) J Mol Struct 1022:220
71. Smith G, Wermuth UD, Healy PC (2005) Acta Cryst E61:o746
72. Smith G, Wermuth UD, Healy PC, White JM (2011) J Chem Crys-
tallogr 41:1649
81. Wang YF (2012) Acta Cryst E68:o1619
82. Bernstein J, Davis RE, Shimoni L, Chang NL (1995) Angew
Chem Int Ed Engl 34:1555
83. Sun W, Shan GZ (2015) Acta Cryst E71:o361
73. Smith G, Wermuth UD (2014) Acta Cryst E70:430
74. Smith G, Wermuth UD, White JM (2001) Acta Cryst E57:o1036
75. Abid S, Hemissi H, Rzaigui M (2007) Acta Cryst E63:o3117
76. Wei SS, Jin SW, Hu ZF, Zhou Y, Zhou YP (2012) Acta Cryst
E68:o3117
Publisher’s Note Springer Nature remains neutral with regard to
jurisdictional claims in published maps and institutional affiliations.
77. Smith G, Wermuth UD, White JM (2003) Acta Cryst E59:o1977
78. Jin SW, Zhang H, Zhao Y, Jin L, Ye XH, Liu H, Wang DQ (2015)
J Mol Struct 1099:304
Affiliations
Zuoran Xie1 · Yuan Lu1 · Shouwen Jin1 · Haomiao Ye1 · Zhong Wang1 · Bin Liu1 · Daqi Wang2
2
* Shouwen Jin
jinsw@zafu.edu.com
Department of Chemical Engineering, Liaocheng University,
Liaocheng 252059, China
1
Jiyang College, ZheJiang A & F University, Zhu’Ji 311800,
China
1 3