Six hydrogen bond directed supramolecular adducts formed between racemic-bis-β-naphthol and N-containing aromatic bases

Article abstract of DOI:10.1016/j.molstruc.2011.12.038

Studies concentrating on hydrogen bonding between the base of exobidentate bis(imidazole) derivatives, and 2-aminoheterocyclic compounds, and (±)-1,10-binaphthalene-2,2′-diol have led to an increased understanding of the role the aromatic N-containing com

Full text of DOI:10.1016/j.molstruc.2011.12.038

Journal of Molecular Structure 1013 (2012) 143–155
Contents lists available at SciVerse ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Six hydrogen bond directed supramolecular adducts formed between
racemic-bis-b-naphthol and N-containing aromatic bases
b
c
b
Shouwen Jin a, , Qiong Dong , Daqi Wang , Wei Zhou
⇑
a Tianmu College of ZheJiang A & F University, Lin’An 311300, PR China
b Faculty of Science, 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:
Received 18 May 2011
Received in revised form 25 December 2011
Accepted 27 December 2011
Available online 11 January 2012
Studies concentrating on hydrogen bonding between the base of exobidentate bis(imidazole) derivatives,
and 2-aminoheterocyclic compounds, and ( )-1,10-binaphthalene-2,20-diol have led to an increased
understanding of the role the aromatic N-containing compounds have in binding with ( )-1,10-binaph-
thalene-2,20-diol. Here anhydrous multicomponent adducts of N-containing aromatic bases such as 1,4-
bis(N-imidazolyl)butane (L1), 1,3-bis(N-benzimidazolyl)propane (L2), 1,4-bis(N-benzimidazolyl)butane
(L3), 1,5-bis(N-benzimidazolyl)-3-oxapentane (L4), 2-amino-4-phenylthiazole (L5), and 2-amino-5,7-
dimethyl-1,8-naphthyridine (L6) have been prepared with ( )-1,10-binaphthalene-2,20-diol (binol). The
six crystalline forms reported are cocrystals of which the crystals and complexes were characterized
by X-ray diffraction analysis, IR, mp, and elemental analysis. The inter-ring angles (naphthol/naphthol)
in the same binol of the six cocrystals ranged from 70.71° to 104.2° as the organic bases varied. In the
six cocrystals, the binols exist either as both of the enantiomers of rac-binol or as only of its single enan-
tiomer. All supramolecular architectures of cocrystals 1–6 are stabilized by O–Hꢀ ꢀ ꢀN hydrogen bonds. In
Keywords:
Crystal structure
Hydrogen bond
Co-crystal
( )-1,10-Binaphthalene-2,20-diol
N-containing aromatic bases
3D framework
addition other non-conventional interactions (CH–p, CH3–p, NH–p, S–p, and p–p interactions) play an
important role in the solid-state packing of co-crystallization as well. These weak interactions combined,
all of the six complexes displayed 3D network structure.
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
features of binol suggest that the binol can be utilized as a struc-
ture-directing component in the co-crystal preparation and adopts
Currently, H-bonding interactions have been widely developed
in the area of crystal engineering, supramolecular chemistry, mate-
rial science, and biological recognition [1–9]. The application of
intermolecular hydrogen bonds is a well known and efficient tool
in the field of organic crystal design because of its strength and
directional properties [9]. As is known, the strong and directional
O–Hꢀ ꢀ ꢀN and O–Hꢀ ꢀ ꢀO hydrogen bonds are frequently used to con-
struct various co-crystals [10].
variousconformationssuitable for self-assembly architectures. Doc-
umented literatures show that the binol can form co-crystals with a
wide range of aromatic diimines derivatives [14]. Also, great efforts
have been devoted to the development of organic molecular crystals
containing a variety of imidazole architectures [15–17]. Among
these supramolecular architectures, however, only a very few
reports described the crystals composed of bridged imidazoles [18–
22] (e.g., 1,4-bis[(imidazol-1-yl)methyl]-benzene [18,22], (bis(1-
methyl-imidazol-2-yl)methyl)-4-nitroimidazol-2-yl)methyl)amine
[20], etc.). As the bridged imidazoles with different flexibility result-
ing different spacer length, when they interact with the binol, they
can adopt various conformation and generate different structures.
Recently 2-aminoheterocyclic compounds have been reported to
form supramolecular compounds with the carboxylic acid deriva-
tives under the multiple hydrogen bonding action [23–24]. In addi-
tion to being planar rigid molecules (the planarity of the molecules
favors aromatic stacking interactions), the 2-aminoheterocyclic
compounds 2-amino-4-phenylthiazole, and 2-amino-5,7-dimethyl-
1,8-naphthyridine may act as potentially tridentate ligands (NNN
and NSN). The binary adduct of the binol and 2-aminoheterocyclic
compounds may display the different hydrogen-bonding patterns
from the three different donor atoms. However to the best of our
There are many interesting hydrogen bonded topological struc-
tures which ranged from infinite 1-D chain to 3-D supramolecular
frameworks [11,12]. Phenols and pyridine moieties are known to
form a variety of supramolecular aggregates via O–Hꢀ ꢀ ꢀN hydrogen
bonds. Phenol–aza/amine interactions also provide a predictable
and robust organizing force to generate a variety of supramolecular
aggregates via O–Hꢀ ꢀ ꢀN hydrogen bonds [13].
However, comparing with various phenol molecules such as res-
orcinol, ( )-1,10-binaphthalene-2,20-diol (binol) is a more flexible
molecule with a scissor-shaped backbone, and also has functional
hydroxy groups for effective hydrogen binding. These structural
⇑
Corresponding author. Tel./fax: +86 571 6374 0010.
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.2011.12.038

144
S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
knowledge there are no reports based on binol and bridged imidaz-
ole and 2-aminoheterocyclic compounds.
It is interesting to exploit the robust and directional recognition
of OH group with N-heterocyclic moieties [25]. As an extension of
the method described in the literature [28–29]. The other chem-
icals and solvents used in this work are of analytical grade and
available commercially and were used without further purifica-
tion. The FT-IR spectra were recorded from KBr pellets in range
our study of weak interactions (hydrogen bonding,
p–p
interac-
4000–400 cmꢁ1 on
a Mattson Alpha-Centauri spectrometer.
tion, and halogen bonding) concerning aromatic N-containing
derivatives [26], herein we report the preparation and structures
of six heteroadducts assembled from 1,4-bis(N-imidazolyl)butane
(L1), 1,3-bis(N-benzimidazolyl)propane (L2), 1,4-bis(N-benzimi-
dazolyl)butane (L3), 1,5-bis(N-benzimidazolyl)-3-oxapentane
(L4), 2-amino-4-phenylthiazole (L5), and 2-amino-5,7-dimethyl-
1,8-naphthyridine (L6) and racemic-bis-b-naphthol (binol)
(Scheme 1), respectively. The six cocrystals are (1,4-bis(N-imidaz-
olyl)butane): (Binol) [(L1). (Binol)] (1), (1,3-bis(N-benzimidazol-
yl)propane): (Binol) [(L2). (Binol)] (2), (1,4-bis(N-benzimidazolyl)
butane): (Binol)2 [(L3). (Binol)2] (3), 1,5-bis(N-benzimidazolyl)-3-
oxapentane: (Binol)2 [(L4). (Binol)2] (4), (2-amino-4-phenylthiaz-
ole): (Binol) (5) [(L5). (Binol)], and (2-amino-5,7-dimethyl-1,8-
naphthyridine)2: (Binol) [(L6)2. (Binol)] (6).
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. Preparation of the cocrystals 1–6
2.2.1. (1,4-bis(N-imidazolyl)butane): (Binol) [(L1)ꢀ(Binol)] (1)
To a methanol solution (2 ml) of 1,4-bis(N-imidazolyl)butane
(L1) (38 mg, 0.2 mmol) was added Binol (57.3 mg, 0.2 mmol) dis-
solved in acetonitrile (8 ml). 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 several days, colorless
block crystals were isolated after slow evaporation of the solution
in air. The crystals were collected and dried in air to give the title
compound [(L1). (Binol)] (1). Yield: 78 mg, 81.84%. M.p. 199–
201 °C. Anal. Calcd for C30H28N4O2 (476.56): C, 75.54; H, 5.88; N,
11.75. Found: C, 75.48; H, 5.79; N, 11.72. Infrared spectrum (KBr
disc, cmꢁ1): 3632s, 3446w, 3135w, 2943w, 1612m, 1591m,
1515m, 1488m, 1448m, 1370w, 1342s, 1238w, 1196m, 1098m,
952w, 877w, 831m, 797w, 724m, 654w, 618w.
2. Experimental section
2.1. Materials and physical measurements
The bis(imidazole) derivatives [27], 2-amino-4-phenylthiazole,
and 2-amino-5,7-dimethyl-1,8-naphthyridine were prepared by
N
N
N
N
N
N
N
N
1,4-bis(N-imidazolyl)butane
L1
1,3-bis(N-benzimidazolyl)propane
L2
O
N
N
N
N
N
N
N
N
1,5-bis(N-benzimidazolyl)-3-oxapentane
L4
1,4-bis(N-benzimidazolyl)butane
L3
N
H2N
H2N
N
N
S
2-amine-5,7-dimethyl-1,8-naphthyridine
L6
2-amine-4-phenylthiazole
L5
OH
OH
racemic-bis-β-naphthol(Binol)
Scheme 1. Hydrogen bond synthons discussed in this paper.

S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
145
2.2.2. (1,3-bis(N-benzimidazolyl)propane): (Binol) [(L2)ꢀ(Binol)] (2)
2.2.6. (2-Amino-5,7-dimethyl-1,8-naphthyridine)2: (Binol) [(L6)2
ꢀ(Binol)] (6)
To an acetonitrile solution (4 ml) of 1,3-bis(N-benzimidazol-
yl)propane (L2) (56 mg, 0.20 mmol) was added Binol (57.3 mg,
0.2 mmol) dissolved in acetonitrile (8 ml). 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 several days,
colorless block crystals were isolated after slow evaporation of
the solution in air. The crystals were collected and dried in air to
give the title compound [(L2)ꢀ(Binol)] (2). Yield: 92 mg, 81.76%.
M.p. 212–213 °C. Anal. Calcd for C37H30N4O2 (562.65): C, 78.91;
H, 5.33; N, 9.95. Found: C, 78.86; H, 5.28; N, 9.91. Infrared spec-
trum (KBr disc, cmꢁ1): 3646s, 3500s, 3360s, 3290s, 3120s, 3040s,
1760s, 1605s, 1580s, 1560s, 1500s, 1440s, 1380s, 1260m, 1240m,
1180m, 1140m, 1060m, 1010m, 970m, 930m, 870m, 760m,
716m, 682m, 620m.
To an ethanol solution (8 ml) of 2-amino-5,7-dimethyl-1,8-
naphthyridine (L6) (34.8 mg, 0.2 mmol) was added Binol
(57.3 mg, 0.2 mmol) dissolved in 8 ml acetonitrile. 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
several days, colorless block crystals were isolated after slow evap-
oration of the solution in air. The crystals were collected and dried
in air to give the title compound [(L6)2ꢀ(Binol)] (6). Yield: 75 mg,
59.26% (based on L6). M.p. 256–258 °C. Anal. Calcd for
C
40H36N6O2 (632.75): C, 75.86; H, 5.68; N, 13.28. Found: C, 75.78;
H, 5.62; N, 13.24. Infrared spectrum (KBr disc, cmꢁ1): 3638s,
3362s, 3306s, 3148s, 3074s, 2980s, 2926s, 2378m, 2318m,
2086w, 1760w, 1672s, 1624s, 1602m, 1540s, 1500m, 1487m,
1448m, 1400m, 1295m, 1240m, 1202m, 1158m, 1088m, 1002m,
928m, 846m, 742s, 706m, 646s, 610m.
2.2.3. (1,4-bis(N-benzimidazolyl)butane): (Binol)2 [(L3)ꢀ(Binol)2] (3)
To
a methanol solution (5 ml) of 1,4-bis(N-benzimidazol-
yl)butane (L3) (58 mg, 0.20 mmol) was added Binol (57.3 mg,
0.2 mmol) dissolved in acetonitrile (8 ml). 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 several days,
colorless block crystals were isolated after slow evaporation of
the solution in air. The crystals were collected and dried in air to
give the title compound [(L3)ꢀ(Binol)2] (3). Yield: 85 mg, 49.24%
2.3. X-ray crystallography and data collection
Suitable crystals were mounted on a glass fiber on a Bruker
SMART 1000 CCD diffractometer operating at 50 kV and 40 mA
using MoK
a radiation (0.71073 Å). Data collection and reduction
were performed using the SMART and SAINT software [30]. 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 [31]. Hydrogen atoms
were introduced at fixed distances from carbon atoms and as-
signed fixed thermal parameters. The hydrogen atoms attached
to the oxygen and the nitrogen atoms were refined isotropically.
Further details of the structural analysis are summarized in Ta-
ble 1. Selected bond lengths and angles for 1–6 are listed in Ta-
ble 2, the relevant hydrogen bond parameters are provided in
Table 3.
(based on L3). M.p. 224–226 °C. Anal. Calcd for
C58H46N4O4
(862.99): C, 80.65; H, 5.33; N, 6.49. Found: C, 80.62; H, 5.31; N,
6.43. Infrared spectrum (KBr disc, cmꢁ1): 3463s, 3442s, 3289m,
3118s, 3047s, 2862s, 2366m, 1759m, 1621m, 1565m, 1458m,
1382m, 1328m, 1243m, 1124m, 1009m, 938m, 862m, 784m,
707m, 663m, 615w.
2.2.4. (1,5-bis(N-benzimidazolyl)-3-oxapentane): (Binol)2
[(L4)ꢀ(Binol)2] (4)
To an ethanol solution (8 ml) of 1,5-bis(N-benzimidazolyl)-3-
oxapentane (L4) (62 mg, 0.20 mmol) was added Binol (57.3 mg,
0.2 mmol) dissolved in acetonitrile (8 ml). 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 several days,
colorless block crystals were isolated after slow evaporation of
the solution in air. The crystals were collected and dried in air to
give the title compound [(L4)ꢀ(Binol)2] (4). Yield: 85 mg, 48.35%
(based on L4). M.p. 236–238 °C. Anal. Calcd for C58H46N4O5
(878.99): C, 79.18; H, 5.23; N, 6.37. Found: C, 79.12; H, 5.18; N,
6.32. Infrared spectrum (KBr disc, cmꢁ1): 3474s, 3440s, 3296m,
3120s, 3080s, 2940m, 2860m, 1960m, 1720m, 1680m, 1604m,
1551m, 1512m, 1456m, 1382m, 1344m, 1292m, 1215m, 1174m,
1106m, 1042m, 878m, 821m, 764m, 723m, 654w, 618w.
3. Results and discussion
3.1. Preparation and general characterization
The bis(imidazole) derivatives (L1–L4), 2-amino-4-phenylthiaz-
ole, and 2-amino-5,7-dimethyl-1,8-naphthyridine all have good
solubility in common organic solvents, such as methanol, ethanol,
dichloromethane, chloroform, and acetonitrile.
In the preparation of the organic cocrystals 1–6, the racemic-
bis-b-naphthols were mixed directly with the bases in the corre-
sponding solution in 1:1 ratio, which was allowed to evaporate
at ambient conditions to give the final crystalline products. In all
of the structures the base molecules are not protonated therefore
the structure can be classified as cocrystals, not ionic compounds.
The six cocrystals are not hygroscopic, and they all crystallized
without solvent molecules accompanied. The elemental analysis
data for the six compounds are in good agreement with their com-
positions. The infrared spectra of the six compounds are fully con-
sistent with their chemical formulas determined by elemental
analysis and further confirmed by X-ray diffraction analysis. H
atoms connected to O or N atoms were well found from the differ-
ence electron density map, which also indirectly confirms the
cocrystal formation.
2.2.5. (2-Amino-4-phenylthiazole): (Binol) [(L5)ꢀ(Binol)] (5)
To a methanol solution (5 ml) of 2-amino-4-phenylthiazole (L5)
(35.2 mg, 0.2 mmol) was added Binol (57.3 mg, 0.2 mmol) dis-
solved in acetonitrile (8 ml). 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 several days, colorless
crystals were isolated after slow evaporation of the mixed solution
in air. The crystals were collected and dried in air to give the title
compound [(L5)ꢀ(Binol)]. Yield: 80 mg, 86.48%. M.p. 243–244 °C.
Elemental analysis performed on crystals exposed to the atmo-
sphere: Calcd for C29H22N2O2S (462.55): C, 75.24; H, 4.75; N,
6.05; S, 6.92. Found: C, 75.22; H, 4.71; N, 5.97; S, 6.86. Infrared
spectrum (KBr disc, cmꢁ1): 3560s, 3458s, 3319s, 3114m, 3062m,
2963m, 2841m, 2717m, 2466w, 2372m, 2209m, 1976w, 1837w,
1783w, 1662w, 1592m, 1533m, 1487w, 1331m, 1251m, 1199m,
1133m, 1074m, 956m, 905m, 848m, 802m, 755m, 727m, 682m,
636m.
The very strong and broad features at approximately 3700–
3100 cmꢁ1 in the IR spectra of the six compounds arise from
O–H or N–H stretching frequencies. Aromatic, imidazolyl, phenyl-
thiazolic, and naphthyridinic ring stretching and bending are
attributed to the medium intensity bands in the regions of
1500–1630 cmꢁ1 and 600–750 cmꢁ1, respectively.

146
S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
Table 1
Summary of X-ray crystallographic data for complexes 1–6.
1
2
3
4
5
6
Formula
Fw
C
30H28N4O2
C37H30N4O2
562.65
C58H46N4O4
862.99
C58H46N4O5
878.99
C29H22N2O2S
462.55
C40H36N6O2
632.75
476.56
T (K)
298(2)
298(2)
298(2)
298(2)
298(2)
298(2)
Wavelength (Å)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
0.71073
Monoclinic
C2/c
14.9212(13)
9.8700(8)
17.9897(15)
90
109.2730(10)
90
2500.9(4)
4
1.266
0.081
1008
0.49 ꢂ 0.48 ꢂ 0.45
2.40–25.02
ꢁ17 6 h 6 16
ꢁ11 6 k 6 6
ꢁ21 6 l 6 20
6111
0.71073
Monoclinic
P2(1)/c
12.0744(15)
9.6562(13)
26.593(3)
90
100.473(2)
90
3048.9(7)
4
1.226
0.077
1184
0.39 ꢂ 0.38 ꢂ 0.26
2.62–25.02
ꢁ14 6 h 6 11
ꢁ11 6 k 6 11
ꢁ23 6 l 6 31
15169
0.71073
Triclinic
P-1
0.71073
Triclinic
P-1
0.71073
Triclinic
P-1
0.71073
Monoclinic
C2/c
20.062(2)
15.8357(15)
10.5822(9)
90
109.3160(10)
90
3172.7(5)
4
1.325
0.084
1336
0.45 ꢂ 0.42 ꢂ 0.16
2.57–25.02
ꢁ23 6 h 6 22
ꢁ17 6 k 6 18
ꢁ12 6 l 6 12
7778
10.7325(9)
10.9564(10)
11.9692(15)
115.088(2)
99.5660(10)
108.6580(10)
1130.5(2)
1
1.268
0.080
454
0.13 ꢂ 0.12 ꢂ 0.06
2.28–25.01
ꢁ11 6 h 6 12
ꢁ13 6 k 6 10
ꢁ12 6 l 6 14
5985
10.5603(12)
11.1141(13)
11.7869(14)
114.2390(10)
101.0700(10)
106.296(2)
1133.7(2)
1
1.287
0.083
462
0.48 ꢂ 0.38 ꢂ 0.29
2.38–25.02
ꢁ11 6 h 6 12
ꢁ8 6 k 6 13
ꢁ13 6 l 6 14
5999
9.4798(8)
11.0126(11)
13.0166(16)
68.2120(10)
87.980(2)
64.8140(10)
1129.6(2)
2
1.360
0.174
484
0.45 ꢂ 0.34 ꢂ 0.25
1.70–25.01
ꢁ10 6 h 6 11
ꢁ13 6 k 6 13
ꢁ15 6 l 6 12
5865
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalcd (Mg/m3)
Absorption coefficient (mmꢁ1
F(000)
)
Crystal size (mm3)
h range (°)
Limiting indices
Reflections collected
Reflections independent (Rint
)
2213 (0.0307)
1.087
5390 (0.0983)
0.855
3926 (0.0264)
0.876
3963 (0.0309)
0.811
3921 (0.0222)
1.007
2792 (0.0438)
1.071
Goodness-of-fit on F2
R indices [I > 2
r
I]
0.0415, 0.0906
0.0695, 0.1122
0.119, ꢁ0.186
0.0655, 0.1555
0.1610, 0.2055
0.187, ꢁ0.206
0.0445, 0.0926
0.0978, 0.1097
0.127, ꢁ0.147
0.0515, 0.1119
0.1267, 0.1352
0.155, ꢁ0.171
0.0496, 0.1137
0.0927, 0.1414
0.279, ꢁ0.228
0.0412, 0.0966
0.0868, 0.1275
0.198, ꢁ0.227
R indices (all data)
Largest diff. peak and hole (e Åꢁ3
)
3.2. Structural descriptions
The dihedral angle between the two naphthalene rings in the same
binol is 72.7°, the dihedral angle between the imidazole ring and
the two naphthalene rings are 105.5°, and 77° respectively. In this
arrangement, two naphthalene rings rotate for more close array
along the C–C bond than those reported by Ji (for the dihedral
angle (72.7°) of the two naphthalene rings in 1 is smaller than
the reported values of 74.9°, and 75.1° by Ji) [14b].
The adjacent binol molecules are parallel to each other, and
they are held together through C–Hꢀ ꢀ ꢀO association (between the
C(9)–H(9) of one naphthyl group and the OH group of another
binol molecule with C–O distance of 3.341 Å) and edge-to-face
3.2.1. X-ray structure of (1,4-bis(N-imidazolyl)butane): (Binol)
[(L1)ꢀ(Binol)] (1)
The compound 1 of the composition [(L1)ꢀ(Binol)] was prepared
by crystallizing equal mol of 1,4-bis(N-imidazolyl)butane and bi-
nol in a mixed solvent of methanol and acetonitrile, in which both
protons of the binol were remained with the O atoms. This struc-
ture is not a solvate. In the asymmetric unit of 1 there existed half
a molecule of 1,4-bis(N-imidazolyl)butane, and half a molecule of
binol, respectively, as shown in Fig. 1(i). Compound 1 crystallizes
as monoclinic block crystals in the space group C2/c.
C–Hꢀ ꢀ ꢀ
p interaction (between C(10)–H(10) of one binol and the
The C–O (O(1)–C(2)) distance concerning the OH group of the
binol is 1.357(2) Å which is similar to the C–O distance in other
binary aromatic aza adduct of binol (1.356(2)–1.364(2))
[14b,14e], which confirms the reliability of adding H atoms exper-
imentally by different electron density onto O atoms, and also
clearly indicates that the binol is not ionized. The H-atoms of both
hydroxyl groups are approximately in plane with the aromatic sys-
tems that they are attached. Intracyclic C–C–C angles span a range
of 117.78(16)–121.59(19)° with the biggest angle found on the
C(9)–C(10)–C(5).
It was found that although the N atom of L1 is involved in
hydrogen bonding interaction with the binol molecule the confor-
mation of 1,4-bis(N-imidazolyl)butane in 1 has not experienced
significant change in comparison to the corresponding neutral
molecule L1 [32]. The imidazole rings in 1 have trans-(ap) position
in respect to C15–C15a bond (angle C14–C15–C15a–C14a, 180°),
which is different from the corresponding angle in the ionic com-
pound 1,10-(1,4-butanediyl)bis(imidazolium) dihydrochloride
[32]. The imidazole ring forms a dihedral angle of 80.4 (2)° with
the plane defined by the C atoms of the –(CH2)4– aliphatic linker
in 1,4-bis(N-imidazolyl)butane, which is larger than the corre-
sponding value in its nitrate salt (62.7 (3)°) [33].
aromatic ring of the other adjacent binol with C–Cg (Cg is the
gravity center of the naphthalene ring of the binol) distance of
ca. 3.475 Å) (Fig. 1(ii)).
Under the above intermolecular interactions the binol mole-
cules formed a 1D chain running along the c axis direction. The
chains were further connected together through C–Hꢀ ꢀ ꢀO and
CH–p interactions along the [100] axis direction to form 2D grid
extending along the ac plane.
The grids formed by binols stacked along the b axis direction in
which the binol molecules at adjacent grids were antiparallely
arranged. And the third grid has the same projection at the ac plane
as the first grid. The L1 molecules were sandwiched between two
adjacent grids through CH–p (between C(13)–H(13) of one imidaz-
ole ring of L1 and the naphthyl group of binol of one grid with C–Cg
distance of 3.717 Å) and O–Hꢀ ꢀ ꢀN interactions (between the naph-
thol OH group of another grid and the terminal N atom of another
imidazole ring of the same L1, O(1)–H(1)ꢀ ꢀ ꢀN(2)#3, 2.704(2) Å).
In this case the L1 molecules were located almost at the center
of the cavities of the grid formed by binols. The L1 molecules sand-
wiched between the same two adjacent grids are parallel to each
other, but the L1 molecules sandwiched between the second grid
and the third grid is almost perpendicular to those sandwiched
between the first grid and the second grid. Such an arrangement
repeated the final structure of the compound displays 3D layer
network structure without channels (Fig. 1(iii)).
The two naphthalene rings in the same binol are almost planar
with the r.m.s deviations of 0.0262 Å, and 0.0218 Å, respectively.
The imidazole ring is also planar with r.m.s deviation of 0.0013 Å.

S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
147
Table 2
Table 3
Selected bond lengths (Å) and angles (°) for compounds 1–6.
Hydrogen bond distances and angles in studied structures of 1–6.
1
D–Hꢀ ꢀ ꢀA
d(D–H) (Å) d(Hꢀ ꢀ ꢀA) (Å) d(Dꢀ ꢀ ꢀA) (Å) <(DHA) (°)
N(1)–C(11)
N(1)–C(14)
N(2)–C(12)
C(1)–C(2)
C(11)–N(1)–
C(13)
N(1)–C(11)
N(1)–C(14)
N(2)–C(12)
C(1)–C(2)
C(11)–N(1)–
C(13)
N(1)–C(11)
N(1)–C(14)
N(2)–C(12)
C(1)–C(2)
C(11)–N(1)–
C(13)
N(1)–C(11)
N(1)–C(14)
N(2)–C(12)
C(1)–C(2)
C(11)–N(1)–
C(13)
1
O(1)–H(1)ꢀ ꢀ ꢀN(2)#3
2
0.82
1.95
2.704(2)
153.4
O(2)–H(2)ꢀ ꢀ ꢀN(4)#1
0.82
0.82
1.91
1.91
2.718(3)
2.679(4)
169.7
155.7
O(1)–H(1)ꢀ ꢀ ꢀN(2)#2
C(13)–N(1)–
C(14)
C(13)–N(1)–
C(14)
C(13)–N(1)–
C(14)
C(13)–N(1)–
C(14)
3
O(2)–H(2)ꢀ ꢀ ꢀN(2)
0.82
0.82
1.88
1.96
2.655(2)
2.7509(19)
157.9
162.4
N(2)–C(11)–N(1) N(2)–C(11)–N(1) N(2)–C(11)–N(1) N(2)–C(11)–N(1)
O(1)–H(1)ꢀ ꢀ ꢀO(2)#2
2
4
N(1)–C(21)
N(1)–C(35)
N(2)–C(22)
N(3)–C(30)
N(4)–C(28)
O(1)–C(2)
C(21)–N(1)–
C(23)
N(1)–C(21)
N(1)–C(35)
N(2)–C(22)
N(3)–C(30)
N(4)–C(28)
O(1)–C(2)
C(21)–N(1)–
C(23)
N(1)–C(21)
N(1)–C(35)
N(2)–C(22)
N(3)–C(30)
N(4)–C(28)
O(1)–C(2)
C(21)–N(1)–
C(23)
N(1)–C(21)
N(1)–C(35)
N(2)–C(22)
N(3)–C(30)
N(4)–C(28)
O(1)–C(2)
C(21)–N(1)–
C(23)
O(3)–H(3)ꢀ ꢀ ꢀO(2)#2
0.82
0.82
1.96
1.87
2.754(2)
2.640(3)
162.9
156.5
O(2)–H(2)ꢀ ꢀ ꢀN(2)
5
O(2)–H(2)ꢀ ꢀ ꢀO(2)#1
O(1)–H(1)ꢀ ꢀ ꢀN(1)#2
N(2)–H(2B)ꢀ ꢀ ꢀO(1)
0.82
0.82
0.86
2.62
2.21
2.35
2.27
3.018(4)
2.861(3)
3.047(3)
3.123(3)
111.4
137.2
138.8
170.2
N(2)–H(2A)ꢀ ꢀ ꢀO(2)#2 0.86
C(23)–N(1)–
C(35)
C(28)–N(3)–
C(30)
C(30)–N(3)–
C(37)
C(23)–N(1)–
C(35)
C(28)–N(3)–
C(30)
C(30)–N(3)–
C(37)
C(23)–N(1)–
C(35)
C(28)–N(3)–
C(30)
C(30)–N(3)–
C(37)
C(23)–N(1)–
C(35)
C(28)–N(3)–
C(30)
C(30)–N(3)–
C(37)
6
O(1)–H(1)ꢀ ꢀ ꢀN(2)#2
0.82
1.94
2.28
2.26
2.718(2)
2.893(3)
3.104(3)
158.2
128.7
167.3
N(3)–H(3B)ꢀ ꢀ ꢀO(1)#3 0.86
N(3)–H(3A)ꢀ ꢀ ꢀN(1)#4 0.86
Symmetry transformations used to generate equivalent atoms for 1: #3 x, y ꢁ 1, z.
Symmetry transformations used to generate equivalent atoms for 2: #1 x, y ꢁ 1, z;
#2 x, ꢁy + 3/2, z + 1/2. Symmetry transformations used to generate equivalent
atoms for 3: #2 ꢁx + 1, ꢁy, ꢁz + 1. Symmetry transformations used to generate
equivalent atoms for 4: #2 ꢁx + 1, ꢁy, ꢁz + 1. Symmetry transformations used to
generate equivalent atoms for 5: #1 ꢁx + 1, ꢁy + 1, ꢁz + 1, #2 ꢁx, ꢁy + 1, ꢁz + 1.
Symmetry transformations used to generate equivalent atoms for 6: #2 ꢁx + 1/2,
ꢁy + 1/2, ꢁz + 1; #3 x + 1/2, y ꢁ 1/2, z; #4 ꢁx + 1, ꢁy, ꢁz + 1.
N(2)–C(21)–N(1) N(2)–C(21)–N(1) N(2)–C(21)–N(1) N(2)–C(21)–N(1)
3
N(1)–C(1)
N(1)–C(8)
N(2)–C(2)
O(2)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
N(1)–C(1)
N(1)–C(8)
N(2)–C(2)
O(2)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
N(1)–C(1)
N(1)–C(8)
N(2)–C(2)
O(2)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
N(1)–C(1)
N(1)–C(8)
N(2)–C(2)
O(2)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
4
N(1)–C(1)
N(1)–C(1)
N(1)–C(1)
N(1)–C(1)
N(1)–C(8)
N(1)–C(8)
N(1)–C(8)
N(1)–C(8)
N(2)–C(2)
N(2)–C(2)
N(2)–C(2)
N(2)–C(2)
O(1)–C(9)
O(1)–C(9)
O(1)–C(9)
O(1)–C(9)
O(3)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
N(2)–C(1)–N(1)
O(3)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
N(2)–C(1)–N(1)
O(3)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
N(2)–C(1)–N(1)
O(3)–C(21)
C(1)–N(1)–C(8)
C(1)–N(2)–C(2)
N(2)–C(1)–N(1)
5
N(1)–C(1)
N(2)–C(1)
O(2)–C(21)
S(1)–C(1)
C(2)–C(4)
C(3)–S(1)–C(1)
N(1)–C(1)–S(1)
N(1)–C(1)
N(2)–C(1)
O(2)–C(21)
S(1)–C(1)
C(2)–C(4)
N(1)–C(1)
N(2)–C(1)
O(2)–C(21)
S(1)–C(1)
C(2)–C(4)
N(1)–C(1)
N(2)–C(1)
O(2)–C(21)
S(1)–C(1)
C(2)–C(4)
C(3)–S(1)–C(1)
N(1)–C(1)–S(1)
C(3)–S(1)–C(1)
N(1)–C(1)–S(1)
C(3)–S(1)–C(1)
N(1)–C(1)–S(1)
6
N(1)–C(1)
N(2)–C(6)
N(3)–C(1)
C(1)–N(1)–C(5)
N(1)–C(1)–N(3)
N(1)–C(1)
N(2)–C(6)
N(3)–C(1)
C(1)–N(1)–C(5)
N(1)–C(1)–N(3)
N(1)–C(1)
N(2)–C(6)
N(3)–C(1)
C(1)–N(1)–C(5)
N(1)–C(1)–N(3)
N(1)–C(1)
N(2)–C(6)
N(3)–C(1)
C(1)–N(1)–C(5)
N(1)–C(1)–N(3)
Symmetry transformations used to generate equivalent atoms for 4: #1 ꢁ x, ꢁy + 1,
ꢁz + 1.
Fig. 1(i). Molecular structure of
1 showing the atomic numbering scheme.
Displacement ellipsoids are drawn at the 30% probability level.
3.2.2. X-ray structure of (1,3-bis(N-benzimidazolyl)propane): (Binol)
[(L2)ꢀ(Binol)] (2)
Cocrystallization of L2 with binol from acetonitrile occurred in a
1:1 ratio to give cocrystal 2. The asymmetric unit of 2 consists of
one molecule of each starting material in the unit cell as shown
in Fig. 2(i). There exist two O–Hꢀ ꢀ ꢀN hydrogen bonds between
the OH group of binol and the N atom of L2 (O(2)–N(4)#1,
2.718(3) Å, and O(1)–N(2)#2, 2.679(4) Å). The L2 forms 1D zigzag
chain running along the b axis direction under the edge to face
adjacent chains were joined together through the interchain CH–p
interaction between the N–CH–N of the benzimidazole moiety and
the benzene ring of L2 with C–Cg distance of 3.491 Å to form a dou-
ble chain extending in the bc plane (Fig. 2(ii)).
The r.m.s deviations of the naphthalene ring atoms in 2 from the
mean planes of the rings containing atoms C1–C10 and C11–C20
are 0.0031 Å and 0.0192 Å, respectively. The dihedral angle be-
tween the two rings is 72.7° which is almost the same as the cor-
responding value in 1. As expected, the benzimidazole rings are
CH–p interaction with C–Cg distance of 3.688 Å between the ben-
zene CH of one L2 and the benzene ring of its adjacent L2. Two such

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S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
planar in which the mean deviations of the benzimidazole rings
containing N3, N4, and N1, N2 atoms from the mean planes are
0.0083 Å and 0.0164, respectively. The dihedral angle between
the two benzimidazole rings in the same L2 is 74.4°. The benzimid-
azole plane containing N3, and N4 atoms makes dihedral angles of
75°, and 93.7° respectively with the above two naphthalene rings.
The benzimidazole ring containing N1, and N2 atoms forms dihe-
dral angle of 0.7° with the naphthalene plane defined by the atoms
C1–C10, indicating the coplanarity of both rings.
One binol molecule is bonded to two adjacent L2 molecules in
the chain with the same half part of the binol, i.e. the OH group
forms one O–Hꢀ ꢀ ꢀN hydrogen bond with the terminal N of one L2
with N–O distance of 2.718 Å, and the CH coming from the same
naphthalene ring as the OH group associates with the benzimid-
Fig. 1(ii). C–Hꢀ ꢀ ꢀp and C–Hꢀ ꢀ ꢀO interactions between binol.
azole ring of another adjacent L2 in the chain through CH–p inter-
action (with C–Cg distance of 3.660 Å). In this case the binol
molecules bonded to the same chain formed by L2 are parallel
and those binol molecules bonded to different chains of the double
chain are antiparallely arranged. Under these two kinds of interac-
tions the compound displays 2D sheet structure (Fig. 2(iii)). Adja-
cent sheets were stacked along the a axis direction through O–
Hꢀ ꢀ ꢀN (between OH group of the first sheet and the imidazole N
atom of the adjacent sheet with N–O distance of 2.679 Å), and
CH–p (between N–CH–N of the benzimidazole of the second sheet
and the naphthalene moiety of the first sheet with C–Cg distance of
3.78 Å) interactions to form double sheet structure. There are also
CH2–O interaction between the propane spacer of the first sheet
and the O atom of the binol of the second sheet with C–O distance
of 3.554 Å. In the double sheet the two adjacent sheets were
slipped some distance from each other. Adjacent double sheets
were further connected together by
p–p interaction between the
naphthalene ring and the benzimidazole ring with Cg–Cg distance
of 3.283 Å along the a axis direction to form 3D layer structure. In
the 3D structure the third sheet has the same projection on the bc
plane as the first sheet.
Fig. 1(iii). 3D layer structure of the compound 1 which is viewed along the c axis.
Fig. 2(i). The structure of 2, showing the atom-numbering scheme. Displacement ellipsoids were drawn at the 30% probability level.

S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
149
Similar with {[Zn(FcCOO)2(L3)]ꢀ2H2O}n [34], the two benzimid-
azole rings in the same L3 molecule of compound 3 were antipar-
allel to each other also, but it is different from the reported
compound of [(H2L3)CdCl4] in which the two benzimidazole rings
are perpendicular to each other (the dihedral angle between the
two benzimidazole rings is 91.1°) [35]. The L3 in 3 is twisted with
the torsion angles of 61.08° and ꢁ61.08° for N1–C8–C9–C9a and
C9–C9a–C8a–N1a, respectively, which is different from our previ-
ously reported results (ꢁ172.6°, and 175.52°) [35], yet it is similar
to the documented value of 58.70° [36].
As expected, the benzimidazole rings are planar (the r.m.s devi-
ation from the mean plane is 0.0035 Å) within the L3 molecule. The
r.m.s deviation of the naphthalene ring bearing C10–C19 atoms
from the mean plane is 0.0167 Å, which forms dihedral angle of
110.7° with the benzimidazole ring. The r.m.s deviation of the
naphthalene ring containing atoms C20–C29 from the mean plane
of the ring is 0.0101 Å, which makes dihedral angle of 60.7° with
the benzimidazole rings. The dihedral angle between two naphtha-
lene rings in the same binol is 97.6° which is greatly larger than
those found in 1, and 2.
Fig. 2(ii). The double chain formed via intrachain and interchain CH–p interactions.
3.2.3. X-ray structure of (1,4-bis(N-benzimidazolyl)butane): (Binol)2
[(L3)ꢀ(Binol)2] (3)
Although the compound 3 was prepared in the same way as
the compound 1, the composition of the compound 3 is different
from 1. Compound 3 of the formula [(L3)ꢀ(Binol)2] (L3 = 1,4-bis(N-
benzimidazolyl)butane) crystallizes in the triclinic P-1 space
group, and there are 1 formula unit in its cell content. In 3 the
asymmetric unit is occupied by one binol and a half L3 molecules
(Fig. 3(i)).
Two binols form homodimers through two pairs of O–Hꢀ ꢀ ꢀO
hydrogen bonding interactions between the OH groups with O–O
distance of 2.7509(19) Å to display a R22ð14Þ ring motif. In this
Fig. 2(iii). 2D sheet structure of the compound 2 viewed along the a axis direction.
Fig. 3(i). Molecular structure of 3 showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

150
S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
Fig. 4(i). Molecular structure of
4 showing the atomic numbering scheme.
Displacement ellipsoids are drawn at the 30% probability level.
Fig. 3(ii). CH–p interaction between the N–CH–N of L3 and the naphthalene ring.
P-1 with unit content of one formula unit also. The L4 ligand
adopts a trans configuration with the planes of the two benzimid-
azole rings in the same L4 molecule antiparallely arranged. The
bridged O atom of the spacer in L4 is disordered over two positions
with occupancies of 0.5 respectively.
The r.m.s deviation of the benzimidazole ring atoms from the
mean plane of the ring containing atoms C1–C7, N1, and N2 is
0.0040 Å. The r.m.s deviations of the naphthalene rings bearing
C10–C19 and C20–C29 atoms from the mean planes are 0.0152 Å,
and 0.0136 Å, respectively. The dihedral angle between the two
naphthalene planes is 95.5° which is slightly smaller than the cor-
responding value in 3, yet it is still greatly larger than that in 1, and
2. The benzimidazole ring forms dihedral angles of 65.3°, and
106.4° respectively with the two naphthalene rings in the same bi-
nol molecule.
regard, the intermolecular O–O distance is slightly smaller than the
corresponding value in (R)-(+)-Binol, (R,S)-( )-Binol, and (S)-(ꢁ)-
Binol in which the O–O distances ranged from 2.86 to 2.96 Å
[37]. In the homodimers the two binol molecules are inversionally
related, and thus the homodimer is constituted by both the enan-
tiomers of rac-binol.
The binol dimers and the L3 were arranged alternatively along
the b axis direction to form a 1D chain. Adjacent chains were con-
nected together by CH–p interaction (Fig. 3(ii)) between the N–
CH–N of L3 and the naphthalene ring with C–Cg distance of
3.749 Å to form a 2D grid (Fig. 3(iii)). The grids were further
stacked along the a axis direction through the CH2–O interaction
(between CH2 of the butane spacer and the OH group of the naph-
thalene unit with C–O distance of 3.394 Å), CH2–
tween CH2 of the butane spacer and the naphthalene ring with C–
Cg distance of 3.640 Å), and CH– interaction (between two naph-
p interaction (be-
The binols also form homodimers through two pairs of intermo-
lecular O–Hꢀ ꢀ ꢀO hydrogen bond between two binols with O–O dis-
tance of 2.754 Å, which is similar to that in 3. The L4 connected the
dimer through O–Hꢀ ꢀ ꢀN hydrogen bond to form a 1D chain running
along the b axis direction, in the chain the binol dimer and the L4
were arranged alternately. Adjacent chains were connected to-
p
thalene rings at two neighboring grids with C–Cg distance of
3.400 Å) to form 3D layer network structure. In this case the adja-
cent grids were also slipped some distance from each other.
gether through CH–p interaction (Fig. 4(ii)) between the naphtha-
3.2.4. X-ray structure of 1,5-bis(N-benzimidazolyl)-3-oxapentane:
(Binol)2 [(L4)ꢀ(Binol)2] (4)
lene rings at the two chains with C–Cg distance of 3.586 Å to form
2D sheet extending on the ab plane (Fig. 4(iii)). The sheets were
further stacked along the c axis direction such that the chains of
the second sheet were just located above the center of two
Similar to 3, the crystal structure of 4 also consists of half a mol-
ecule of L4, and one molecule of binol in the asymmetric unit
(Fig. 4(i)). The compound crystallizes in a triclinic space group
Fig. 3(iii). 2D grid structure of 3 running along the b axis direction.

S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
151
cocrystal 3 there are also CH2–
p
and CH2-O interactions between
adjacent sheets.
3.2.5. X-ray structure of (2-amino-4-phenylthiazole): (Binol)
[(L5)ꢀ(Binol)] (5)
The compound 5 was also prepared by crystallizing of 2-amino-
4-phenylthiazole with binol in 1:1 ratio, which crystallizes as tri-
clinic block crystals in the centrosymmetric space group P-1. The
compound consists of one molecule of each reactant in the unit cell
(Fig. 5(i)).
The compound is also a cocrystal. As shown in table 2, all the
bond angles and bond distances are in the normal range. The O–
C bond distance concerning the naphthol group was 1.370(3) Å,
which is also expected for neutral C–O bond distance. But it is
somewhat longer than that (1.357(2) Å) in compound 1. The differ-
ence between the two C–O bonds is 0.013 Å which is due to the fact
that in 5 the O atom is involved in forming more hydrogen bonds
than the O atom in 1, as shown in table 3. The angle C3–S1–C1
(88.5 (2)°) is similar to the corresponding angle in the neutral
molecule (88.7 (2)°) [38], yet it is smaller than that in the salt
Fig. 4(ii). CH–
chains.
p interaction between the naphthalene rings at the two adjacent
adjacent chains in the first sheet. Such stacks repeated that the fi-
nal structure of the title compound displayed 3D network structure
without channels when viewed along the c axis direction. Like
Fig. 4(iii). 2D sheet structure of 4 extending on the ab plane.
Fig. 5(i). Molecular structure of 5 showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

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S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
The 2-amino-4-phenylthiazole molecule was bonded to the bi-
nol molecule through one N–Hꢀ ꢀ ꢀO hydrogen bond between the
amine group of L5 and one OH group of binol, one O–Hꢀ ꢀ ꢀN hydro-
gen bond between another OH group of the binol and the ring N
atom of L5. There are edge to face CH–
tance of 3.553 Å between L5 and binol (Fig. 5(ii)). And there are
also NH– interactions between the amine group of L5 and the bi-
p interactions with C–Cg dis-
p
nol ring with N–Cg distance of 3.532 Å. The 2-amino-4-phenyl-
thiazole molecule and the binol molecule formed heterodimers
through the above mentioned weak interactions. Such adjacent
heterodimers were connected together by CH–p interaction be-
tween the CHbinol and the benzene ring of L5 with C–Cg distance
of 3.639 Å to form a 1D chain running along the a axis direction.
Such chains were connected together through O–Hꢀ ꢀ ꢀO hydrogen
bonds between two OH groups of two adjacent chains with O–O
distance of 3.018 (4) Å, which is similar to the published data in
(R)-(+)-binol, and (S)-(ꢁ)-binol (2.96 Å) [37]. Here the intermolec-
ular O–Hꢀ ꢀ ꢀO hydrogen bond is slightly weaker than that in 3, and
4. There exist N–Hꢀ ꢀ ꢀO hydrogen bonds between the amine group
of L5 in one chain and the OH group of the adjacent chain with N–O
distance of 3.048 Å, which is in the upper limit of the sum of the
Fig. 5(ii). Edge to face CH–p interactions between L5 and binol.
2-amino-4-phenylthiazole hydrobromide monohydrate (90.17°)
[39]. This may be due to the difference of the hydrogen bonding
strength in the corresponding compound. The dihedral angle be-
tween the planes of the phenyl and thiazole rings in the same L5
molecule is 17.7 (3)°, which is also smaller than the value
(19.23°) in 2-amino-4-phenylthiazole hydrobromine monohy-
drate. But the 2-amino-4-phenylthiazole in compound 5 is less pla-
nar than the neutral L5 in which the dihedral angle between the
phenyl ring and the thiazole ring is (6.2(3)°) [38]. The planarity
of 5 is further verified by the shorter C(2)–C(4) bond distance
[1.466(4) Å] in 5 compared with the value of 1.506 Å found in 2-
amino-4-phenylthiazole hydrobromine monohydrate [39].
The two naphthalene rings in the same binol are almost planar
with the r.m.s deviations of 0.0047 Å, and 0.0037 Å respectively.
The dihedral angle between the two naphthalene rings in the same
binol is 104.2°, the dihedral angles between L5 and the two naph-
thalene rings in the same binol are 88.7°, and 76.3° respectively,
indicating that L5 is almost perpendicular with one half part of
the binol moiety.
van der Waals radii for N and O (3.07 Å) [40]. There are also S–
p
interactions between the S atom of the thiazole ring in one chain
and the naphthalene ring of the adjacent chain with the S–C con-
tact of 3.452 Å which is similar to the previously published litera-
ture data [41]. But the S–C contact is in the lower limit of the
recently reported S–C contact values [3.390–3.888 Å] [42]. In the
adjacent chains the corresponding naphthalene and the thiazole
moieties were antiparallely arranged. The adjacent chains were
joined together through the above mentioned collective weak
interactions to form a double chain structure. Such double chains
were further connected together by CH–O interaction between
CH of the benzene ring of L5 and O atom from the OH group of bi-
nol with C–O distance of 3.581 Å to form a 2D corrugated sheet
extending on the ac plane (Fig. 5(iii)). Adjacent sheets were further
stacked along the b axis direction through CH–p interactions
Fig. 5(iii). 2D corrugated sheet of 5 extending on the ac plane.

S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
153
Fig. 6(i). Molecular structure of 6 showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
between CH of the naphthyl group of one sheet and the benzene
ring of L5 at the adjacent sheet with C–Cg distance of 3.737 Å to
form 3D network structure.
3.2.6. X-ray structure of (2-amino-5,7-dimethyl-1,8-naphthyridine)2:
(Binol) [(L6)2ꢀ(Binol)] (6)
The compound 6 of the composition [(L6)2ꢀ(Binol)] was pre-
pared by crystallizing equal mol of 2-amino-5,7-dimethyl-1,8-
naphthyridine and binol, in which the proton of binol was not
transferred to any N atoms of the naphthyridine moiety. This struc-
ture is also an anhydrous cocrystal. In the asymmetric unit of 6
there existed one molecule of 2-amino-5,7-dimethyl-1,8-naph-
thyridine, and a half molecule of binol, as shown in Fig. 6(i).
The C–O distances involving the OH group of the binol are
1.358(3) Å which is similar to the above corresponding data and
the documented results as well. The N–Hꢀ ꢀ ꢀO hydrogen bond is
formed between the amine group of L6 and the OH group of binol
(N(3)–H(3B)ꢀ ꢀ ꢀO(1)#3, 2.893(3) Å), there does not exist ionic N+–
Fig. 6(ii). The head to tail p–p interaction and the head to head CH3–p interaction
between L6.
Fig. 6(iii). 3D ladder structure of 6.

154
S. Jin et al. / Journal of Molecular Structure 1013 (2012) 143–155
Hꢀ ꢀ ꢀOꢁ hydrogen bond. There was also an O–Hꢀ ꢀ ꢀN (O(1)–
H(1)ꢀ ꢀ ꢀN(2)#2, 2.718(2) Å) hydrogen bond between the OH group
of the binol and the ring N atom of the pyridine bearing the CH3
group. As expected, the naphthyridine ring is planar (the mean
deviation from plane is 0.0207 Å within the L6 molecule). The
r.m.s deviation of the naphthalene ring containing atoms C11–
C20 in 6 from the mean plane of the ring is 0.0072 Å. The dihedral
angle between the plane formed by C11–C20 atoms and the naph-
thyridine ring is 67°. The torsion angle between the two naphtha-
lene rings in the same binol is ca. 70.71°, which is agreement with
the value in 1, and 2.
5. Supporting information available
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic data center, CCDC
Nos. 791894 for 1, 799292 for 2, 799891 for 3, 800023 for 4,
791893 for 5, and 800874 for 6. 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.
Acknowledgment
Two L6 formed dimers through intermolecular hydrogen bond-
ing (N–Hꢀ ꢀ ꢀN) interactions of the type DA–AD between two pyri-
dine rings containing the amine group. Two binol molecules
were each bonded to the L6 dimer through one N–Hꢀ ꢀ ꢀO and one
O–Hꢀ ꢀ ꢀN hydrogen bonding interactions arising from the same
OH group (Table 3). In this case the two binol molecules were
inversionally located, and therefore the binol is not constituted
by only a single enantiomer but constituted by both the enantio-
mers of rac-binol. In the L6 dimers the two L6 molecules are also
inversionally located.
We gratefully acknowledge the financial support of the Educa-
tion Office Foundation of Zhejiang Province (Project No.
Y201017321) and the financial support of the Zhejiang A & F Uni-
versity Science Foundation (Project No. 2009FK63).
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