Synthesis, structure, and supramolecular chemistry of three azide manganese complexes with 2, 6-Bis(benzimidazol-2-yl)pyridine

Article abstract of DOI:10.1002/zaac.201100542

Three azide complexes with the tridentate ligand 2, 6-bis(benzimidazol-2- yl)pyridine (H₂BBIP) were synthesized and their complicated supramolecular interactions were investigated with single-crystal X-ray diffraction. Interestingly, the complexes are assembled by bifurcated hydrogen bonding, double helical π-π stacking, or anion-π stacking interactions of the benzimidazole rings by tuning the reaction conditions (temperature, ratio, solvent). Complex 1 is a mononuclear compound, namely, Mn(H ₂BBIP)N₃(CH₃O)·CH₃OH. In its 3D supramolecular network, the nitrogen atom of the azide anion is acting as hydrogen bonding bifurcated acceptor. Complex 2 is a dinuclear compound, namely, Mn₂(H₂BBIP)₂(N₃) ₂·(H₂O)_0.5. The dinuclear unit is connected by intramolecular π-π stacking interactions. Furthermore, double helical π-π stacking interactions in the benzimidazole rings are observed. Complex 3, Mn₂(H₂BBIP)₂(N ₃)₂·CH₃OH, can be formulated as a pseudopolymorph of complex 2, which exhibits intramolecular π-π stacking interactions as well as anion-π interactions in the dinuclear unit. Copyright

Full text of DOI:10.1002/zaac.201100542

ARTICLE
DOI: 10.1002/zaac.201100542
Synthesis, Structure, and Supramolecular Chemistry of Three Azide
Manganese Complexes with 2,6-Bis(benzimidazol-2-yl)pyridine
Chuan-Feng Wang,*[a] Guo-Liang Dai,[a] Zheng-Neng Jin,[a] and Zhi-Cai He[a]
Keywords: 2,6-Bis(benzimidazolyl)pyridine; Anion–π interaction; Azide complexes; Pseudopolymorphism; Manganese
Abstract. Three azide complexes with the tridentate ligand 2,6-
bis(benzimidazol-2-yl)pyridine (H2BBIP) were synthesized and their
is acting as hydrogen bonding bifurcated acceptor. Complex 2 is a
dinuclear compound, namely, Mn2(H2BBIP)2(N3)2·(H2O)0.5. The dinu-
complicated supramolecular interactions were investigated with single- clear unit is connected by intramolecular π–π stacking interactions.
crystal X-ray diffraction. Interestingly, the complexes are assembled Furthermore, double helical π–π stacking interactions in the benzimid-
by bifurcated hydrogen bonding, double helical π–π stacking, or azole rings are observed. Complex 3, Mn2(H2BBIP)2(N3)2·CH3OH,
anion–π stacking interactions of the benzimidazole rings by tuning can be formulated as a pseudopolymorph of complex 2, which exhibits
the reaction conditions (temperature, ratio, solvent). Complex 1 is a
mononuclear compound, namely, Mn(H2BBIP)N3(CH3O)·CH3OH. In
its 3D supramolecular network, the nitrogen atom of the azide anion
intramolecular π–π stacking interactions as well as anion–π interac-
tions in the dinuclear unit.
cylindrical symmetry.[5e] Due to our longstanding interests in
the coordination chemistry, structures, and properties of azide
complexes, we want to apply the azide ion as building block
to explore the hydrogen bonding patterns, effects on crystal
packing and pseudopolymorphism of the respective com-
plexes. We were particularly interested in the question to what
extent the electronic structure of the coordinated azide ion is
changed to dictate the transformation of the hydrogen bonding
patterns. Inspired by the discovery of veiled anion–π interac-
tions,[4b,4c,6,7] we wanted to employ multifunctional ligand 2,6-
bis(benzimidazol-2-yl)pyridine (H2BBIP) to tune its subtle
electronic structure of the respective complexes due to its large
π-conjugated system, which has not been fully explored for
the azide complex and to explore the noncovalent interactions
in its metal complexes.
Derivatives of pyridine play a pivotal role in modern coordi-
nation chemistry, and a number of complexes with these li-
gands have been synthesized and characterized. Compared
with other pyridine derivatives, H2BBIP is able to chelate met-
als ion by acting as a tridentate ligand that exhibits variable
coordination modes and noncovalent interactions,[8,9] such as
hydrogen bonding, π–π stacking, and D–H···π interactions;
even promising and intriguing observations on N···π interac-
tions due to the big union involving pyridine, imidazole, and
benzene rings particularly with azide as co-ligand could be
made.[4b,5e] Azide manganese complexes have fascinated
chemists over the last two decades and their structures, mag-
netism, and catalytic properties are well investigated. In this
paper, azide ions are used as a new candidate to assemble
anion–π interactions with the big π system H2BBIP. Herein we
report structures and detailed noncovalent interactions of three
MnII azide complexes with the ligand H2BBIP (L).
Introduction
Crystal engineering is a flourishing topic.[1] Significant ef-
forts have been made to prepare diverse and specifically custo-
mized materials by crystal engineering, in order to develop
methods for efficient and controllable assembly reactions.[1–3]
Several kinds of weak interactions such as directing hydrogen
bonding and less directing π–π stacking interactions, lp–π, cat-
ion–π, and even anion–π interactions are able to control the
assembly reactions by using various rationally designed build-
ing units. By constructing effective building elements for
metal-containing clusters or polymers, many examples for hy-
drogen bonding interactions were obtained,[2] and the hydro-
gen bonding patterns were surveyed. Besides, π–π stacking
interactions involving aromatic rings as well as lp–π, cation–
π and even anion–π interactions have also been widely recog-
nized as important noncovalent interactions.[4]
–
Pseudohalogen azide anions (N3 ) are widely used as bridg-
ing groups in the reported complexes because of their effective
exchange interactions with versatile coordination modes,
which enable constructing complexes of great diversity de-
pending on the reaction environment.[5] Recently, it was shown
that azide ions can be used as effective building blocks to form
predictable hydrogen bonding interactions in the crystal pack-
ing, depending on their coordination – if the azide ions were
coordinated by metal ions into azide complexes or just as hy-
drogen bonding acceptors D–H···N (azide ion) despite of their
* Prof. Dr. C.-F. Wang
E-Mail: chfwang@tzc.edu.cn
[a] School of Pharmaceutical & Chemical Engineering
Taizhou University
Zhejiang Linhai, P. R. China
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/zaac.201100542 or from the au-
thor.
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Z. Anorg. Allg. Chem. 2012, 638, (9), 1340–1344

Azide Manganese Complexes with 2,6-Bis(benzimidazol-2-yl)pyridine
Results and Discussion
In the crystal structure of the complex Mn(H2BBIP)
N3(CH3O)·CH3OH‡ (1), one MnII ion, one neutral tridentate
H2BBIP ligand, one azide ion and two methanol molecules are
present in the independent crystallographic unit (Figure 1).
One coordinated methanol molecule is deprotonated as anionic
counterion. Each MnII ion has a hexacoordinate arrangement,
MnN4O2, in which the basal plane is composed of one nitrogen
atom (N6) of the azide anion and three nitrogen atoms (N1,
N3, and N4) from the tridentate ligand L (Mn–N length rang-
ing from 2.165–2,273 Å). The remaining two axial coordina-
tion sites are occupied by two oxygen atoms from two meth-
anol molecules (Mn–O1 = 2.192 Å; Mn–O2 = 2.302 Å). Con-
sidering the shorter Mn–O1 bond length, the corresponding
methanol molecule is suggested to be the deprotonated one.
The mononuclear units are bridged into a fish-steak arrange-
ment by hydrogen bonding N2–H···N8 [symmetry: x–1, y, z;
d(H···A) 2.059 Å; ϽDHA 164.46°; d(D···A) 2.897 Å] between
two different H2BBIP ligands (Figure 2). At the same time, the
N8 atom acts as a bifurcated acceptor to form another hydro-
gen bonding interaction O2–H···N8 [d(D···A) 2.856 Å], and the
corresponding methanol molecule is neutral (Figure 2). Based
on the hydrogen bonding O2–H···N8 and the expected π–π
stacking interactions (center to center distance = 3.602 Å) be-
tween two imidazole rings of H2BBIP ligands from two re-
verse extended steak tapes, a 2D supramolecular network is
constructed. The resulting 2D net is connected into a 3D net-
work by hydrogen bonding N5–H···O1 [symmetry: –x+3/2, y–
1/2, –z+1/2; d(H···A) 1.953 Å; ϽDHA 143.73°; d(D···A)
2.695 Å] (Figure S1, Supporting Information).
Figure 2. Linking interactions between the units in complex 1 (hydro-
gen bonds shown as dotted lines).
3.927 Å). In the nano unit, the bond lengths of Mn1–N in the
basal plane (Mn1–N6, Mn1–N6A, Mn1–N3, and Mn1–N9) are
2.252, 2.193, 2.290, and 2.200 Å, respectively. Two axial
Mn1–N bonds (Mn1–N1 and Mn1–N4) are slightly longer
with a range of 2.306 and 2.361 Å. However, the end-on azido
bridging ligand is asymmetrically coordinated to MnII ions, in
which the Mn1–N6 of 2.252 Å is slightly longer. The
Mn1···Mn1A distance is 3.480 Å, and the Mn1–N6–Mn1A an-
gle is 103.1° (Figure 3). To the best of our knowledge, the M–
N(azide)–M angle found in complex 2 is similar to those in
other double end-on azido dinuclear complexes.
Figure 3. Intramolecular locking π–π stack interactions in complex 2
(hydrogen and oxygen atoms are omitted for clarity).
Figure 1. Molecular structure of complex 1.
As shown in Figure 3, each manganese ion has a distorted
hexacoordinate arrangement, MnN6, in which the basal plane
Between the dinuclear units, there are abundant hydrogen
is composed of three nitrogen atoms (N6 and N6A from the bonds (as shown in Figure S2, Supporting Information). In the
bridging azide anions; N9 from the terminal azide anion) and b direction, there are hydrogen bonds N5–H5A···N11 (sym-
one nitrogen atom from the tridentate ligand L, as well as two metry: x, y–1, z) between the imidazole rings and azide N11
nitrogen atoms (N1 and N4) from the imidazole rings of the atom [d(H···A) 2.065; ϽDHA 166.27°; d(D···A) 2.908 Å]. In
H2BBIP ligand at two axial coordinate sites. By double end- the c direction, there are pairs of hydrogen bonds N2–
on azido bridging ligands, a nano dinuclear molecule with di- H2A···N11 [symmetry: –x+1, –y+1, –z+2; d(H···A) 1.987;
mensions of 1.43 nmϫ1.37 nm is formed, which is stabilized ϽDHA 171.11°; d(D···A) 2.840 Å], pairs of N2–H2A···N10
by locked pattern π–π stacking interactions between the two [symmetry: –x+1, –y+1, –z+2; d(H···A) 2.549; ϽDHA
pairs of the pendant phenyl rings in the dinuclear structure 169.06°; d(D···A) 3.397 Å] and pairs of C9–H9A···N10 [sym-
with the shortest contact of 3.567 Å (centroid to centroid of metry: –x+1, –y+1, –z+2; d(H···A) 2.593; ϽDHA 166.1°;
Z. Anorg. Allg. Chem. 2012, 1340–1344
© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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C.-F. Wang, G.-L. Dai, Z.-N. Jin, Z.-C. He
ARTICLE
d(D···A) 3.503 Å)] between two dinuclear units (Figure S2). In end-on azido bridging ligands are asymmetrically coordinated
view of N10, hydrogen bonds C9–H9A / N2–H2A···N10 are to MnII ions too, in which the Mn1–N1A bond length
bifurcated. By the two pairs of bifurcated hydrogen bonds, a (2.307 Å) is longer than the Mn1–N1 bond length (2.117 Å).
2D noncovalent network was built, which is further stabilized
by hydrogen bonds N5–H5A···O1 between the imidazole rings
and the hydroxyl oxygen atoms of solvents [d(H···A) 2.366;
ϽDHA 144.46°; d(D···A) 3.107 Å]. Furthermore, the weak in-
tramolecular π–π stacking interactions between the two pen-
dant phenyl rings in the dinuclear units are further extended by
stronger intermolecular side to side π–π stacking interactions
between the pendant phenyl rings and the imidazole rings with
the shortest contact of 3.363 Å (centroid to centroid of
4.310 Å) (Figure 4). By the double helical π–π stacking inter-
actions, which are composed of alternating intermolecular and
intramolecular stacking, the 2D nets are joined into 3D net-
works.
Figure 5. Dinuclear units of complex 3 (anion/π–π stacking interac-
tions shown as open dashed lines).
As expected, there also exist intramolecular face-to-face π–
π stacking interactions between the two pairs of the pendant
phenyl rings in the dinuclear unit with a shortest contact of
3.506 Å. Interestingly, there exists anion–π interactions be-
tween azide N6 atom and the imidazole ring with a shortest
contact of 3.461 Å for N6 to N8 (N6···centroid 3.683 Å). By
hydrogen bonding N7–H7A···N6 [symmetry: –x, –y, –z;
d(H···A) 2.002; ϽDHA 176.51°; d(D···A) 2.861] and edge-to-
edge π–π stacking interactions with a shortest contact of
3.447 Å for N7AB–N7C, the dinuclear units are linked to form
a ladder-like supramolecular chain (Figure 6). These edge-to-
edge π–π stacking interactions may facilitate the formation of
the intramolecular anion–π interactions between the N6 atom
and the imidazole ring. The azide anion and the H2BBIP ligand
Figure 4.. Double helical π–π stack interactions in complex 2 (hydro-
gen bonds are shown as dotted lines π–π stacking interactions shown
as open dashed lines and all hydrogen and oxygen atoms are omitted). act as the pointer and the scale of a table balance. These three
kinds of supramolecular interactions form a cycle knot to bind
As illustrated in Figure S3 (Supporting Information), each the two contiguous units. Next, the chains are interdigitated
manganese ion has a hexacoordinate arrangement, in which the into 3D nets by edge-to-face π–π stacking interactions between
basal plane is composed of one nitrogen atom (N1) of the the edges (C13–C14) of the phenyl rings and the pendant
bridging azide anion and three nitrogen atoms (N8, N10, and phenyl rings and the imidazole rings, with shortest contacts of
N11) of the tridentate ligand L. Among them, one nitrogen 3.737 and 3.818 Å, respectively (Figure S4). In the b direction,
atom is from the pyridine ring and the others stem from the 1D channels with dimensions of 5ϫ7 Å are formed. Further-
imidazole ring. The remaining two axial coordinate sites are more, the solvent methanol molecules are anchored in the 1D
occupied by two nitrogen atoms of the azide anions, one is channels by hydrogen bonds N9–H9A···O1 between the imid-
from the symmetry related azide bridging anion (N1A) and the azole rings and hydroxyl oxygen atoms of solvents [d(H···A)
other is from another terminal azide anion. A dinuclear molec- 1.936 Å; ϽDHA 169.39°; d(D···A) 2.785 Å] (Figure S5).
ular structure is also bridged by the double end-on azide Therefore, a 3D supramolecular microporous network is built.
anions, to give a Mn1···Mn1A distance of 3.423 Å and a Mn1–
The properties of the anion can play an undisputed vital role
N1–Mn1A angle of 101.3° (Figure 5), which is a pseudopoly- for applications of anion–π interactions in crystal engineering.
morph of complex 2. The M–N(azide)–M angle found in com- Although the azide ion has been recognized as a good building
plex 3 is also similar to other double end-on azido dinuclear block in crystal engineering, this theoretically predicted bind-
complexes. In the equatorial plane, the bond lengths of M–N ing mode is confirmed experimentally by the first time.[4b,5e]
–
(Mn1–N1, Mn1–N8, Mn1–N10, and Mn1–N11) are 2.117, Compared to the planar anion NO3 , which was confirmed by
2.259, 2.261, and 2.252 Å, respectively. However, the double nitrate and pyrimidinium rings,[7d] the linear azide anion is also
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© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2012, 1340–1344

Azide Manganese Complexes with 2,6-Bis(benzimidazol-2-yl)pyridine
of the dicarboxylic acid (2,6-pyridinedicarboxylic acid) with a diamine
(1,2-diaminobenzene) in syrupy polyphosphoric acid at 220 °C in lit-
erature.[10]
General: Elemental analyses (C, H, N) were performed with a Perkin-
Elmer 240 analyzer. IR spectra were recorded with a Nicolet Magna-
IR 750 spectrometer equipped with a Nic-Plan microscope in the range
4000–400 cm–1.
Crystals for X-ray structural study were picked from the reaction mix-
ture. The experiment was carried out with a Bruker-Nonius Kappa
CCD diffractometer at room temperature [296(2) K]. Crystal data and
details of experiment are listed in Table 1. All calculations were per-
Figure 6. Linking interactions between units in complex 3 (hydrogen
bonds are shown as dotted lines and π–π stacking interactions as open
dashed lines. All hydrogen atoms are omitted for clarity).
formed with the SHELX-97 program package[11]
.
Mn(H2BBIP)N3(CH3O)·CH3OH (1): Reaction of H2BBIP (0.0622 g,
0.2 mmol), Mn(ClO4)2·6H2O (0.0718 g, 0.2 mmol), NaN3 (0.0264 g,
0.4 mmol), and CH3OH (10 mL) in a 25 mL Teflon-lined bomb at
130 °C for two days. Yellow block crystals were obtained. Anal. for
C21H20MnN8O2: calcd. C 53.51; H 4.28; N 23.77%; found: C 53.34;
an interesting example for anion–π interactions. Because
–
spherical anions, such as halide ions and polyatomic BF4 ,
–
–
PF6 , ClO4 and so on, can be more ready for access to the
formation of anion–π bonding in a little longer distance and
less directional, particularly when π systems are heterocycle
aromatic rings, which are often electronical asymmetric.[4b]
The distance N6 to centroid of imidazole ring 3.683 Å in com-
plex 3 is similar to the longest 3.53 Å between nitrate and
pyrimidinium rings.[7d] However, no anion–π bonding was ob-
served in its pseudopolymorph 2. We carefully study the non-
covalent interactions between the neighboring dinuclear units,
subtle interplay among different noncovalent interactions
maybe make reinforcing cooperativity. The hydrogen bonding
N7–H7A···N6 steers the orientation of the antenna-like azide
ion in spite of the aromatic rings acting as hydrogen bonding
donor, which is further reinforced by π–π interactions between
the neighboring imidazole rings (the shortest contact of
3.447 Å for N7AB–N7C). The cooperativity of three different
noncovalent interactions forms an interplay pseudoknot to bind
them. This phenomenon does not exist in complex 2, in which
double helical π–π interactions involving benzimidazole rings
play a directing role, the reason may be deriving from disorder
in this pseudopolymorph that is assembled in different condi-
tions. Although the linear azide anion has been theoretically
explored on its anion–π interaction almost ten years ago,[6d]
and just when this manuscript being prepared anion–π interac-
tion involving CN– has just been reported,[7f] we think that we
are still be obliged to demonstrate the interesting example of
–
H 4.16; N 24.02%. IR (main bands): ν˜ = 2046 vs. (νas of N3 ) cm–1.
Mn2(H2BBIP)2(N3)2·(H2O)0.5 (2): A solution of H2BBIP (0.0627 g,
0.2 mmol) in CH3OH (15 mL) was added dropwise under stirring into
a mixture of Mn(ClO4)2·6H2O (0.0726 g, 0.2 mmol) in CH3OH (5 mL)
and NaN3 (0.0255 g, 0.4 mmol) in CH3OH (5 mL). After continuing
the reaction for 30 min, a yellow filtrate was left standing for more
than four days to give yellow block crystals. Anal. for
C38H28Mn2N22O: calcd. C 49.68; H 3.07; N 33.54%; found: C 49.51;
H 3.16; N 33.17%. IR (main bands): ν˜ = 2079 and 2047 vs. (νas of
–
N3 ) cm–1.
Mn2(H2BBIP)2(N3)2·CH3OH (3): A solution of H2BBIP (0.0624 g,
0.2 mmol) in CH3OH (10 mL) was added dropwise under stirring into
a mixture of Mn(ClO4)2·6H2O (0.0731 g, 0.2 mmol) in C2H5OH
(5 mL) and NaN3 (0.0261 g, 0.4 mmol) in deionized water (2.5 mL).
After continuing the reaction for 30 min, a yellow filtrate was left
standing for one day to give yellow block crystals, about for eleven
days, lots of sample was obtained. Anal. for C20H17MnN11O: calcd. C
49.80; H 3.55; N 31.94%; found: C 49.67; H 3.27; N 32.16%. IR
–
(main bands): ν˜ = 2052 vs. (νas of N3 ) cm–1.
Crystallographic data (excluding structure factors) for the structures in
this paper have been deposited with the Cambridge Crystallographic
Data Centre, CCDC, 12 Union Road, Cambridge CB21EZ, UK. Copies
of the data can be obtained free of charge on quoting the depository
numbers CCDC-849394 (1), CCDC-849395 (2), and CCDC-849396
(3) (Fax: +44-1223-336-033; E-Mail: deposit@ccdc.cam.ac.uk, http://
www.ccdc.cam.ac.uk).
–
anion–π interaction involving N3 .
Conclusions
Supporting Information (see footnote on the first page of this article):
View down the y axis of complex 1 (hydrogen bonds are shown as
dotted lines); view down the x axis of complex 2; crystallographic unit
of complex 3 (methanol solvent molecule is omitted); view down the
x axis of complex 3 (hydrogen bonds are shown as dotted lines); 1D
These results represent a good example that the linear azide
ion in combination with a large π system can be tuned to facili-
tate the formation of anion–π bonding interactions, and pro-
vide a new insight into the properties of complexes with the channels in the b direction of complex 3 with dimensions of 5 ϫ 7 Å.
azide ion and the large π-conjugated ligand H2BBIP.
Acknowledgement
Experimental Section
The authors thank for the financial supports of Zhejiang Provincial
Synthesis of H2BBIP: The trichelate ligand, 2,6-bis(benzimidazolyl) Natural Science Foundation of China under Grants No. Y4100508 and
pyridine (H2BBIP) was prepared by a one-step condensation reaction
Y4090387.
Z. Anorg. Allg. Chem. 2012, 1340–1344
© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1343

C.-F. Wang, G.-L. Dai, Z.-N. Jin, Z.-C. He
ARTICLE
Table 1. Crystal data and structure refinement for complexes 1–3.
1
2
3
Formula
Mr
C21H20MnN8O2
471.39
C38H28Mn2N22O
918.70
C20H17MnN11O
482.39
T /K
293(2)
296(2)
296(2)
λ /Å
0.71073
monoclinic,
P21/n
9.9567(17)
8.1525(14)
26.461(5)
90
98.986(2)
90
2121.6(6)
4, 1.476
0.659
0.71073
0.71073
monoclinic,
P21/n
9.297(2)
11.877(3)
20.658(5)
90
96.698(3)
90
2265.5(8)
4, 1.414
0.619
Crystal system,
Space group
a /Å
b /Å
c /Å
triclinic,
¯
P1
9.975(3)
10.311(3)
11.072(3)
96.325(4)
109.274(3)
101.672(4)
1033.3(5)
1, 1.476
α /deg
β /deg
γ /deg
V /Å3
Z, ρ /Mg·m–3
μ /mm–1
F(000)
0.673
468
972
988
Crystal size /mm
0.35ϫ0.2ϫ0.17
0.3ϫ0.2ϫ0.15
0.3ϫ0.2ϫ0.12
θ range /deg
Limiting indices
1.56 to 25.25
–11 Յ h Յ 9,
–9 Յ k Յ 9,
–31 Յ l Յ 31
15110
3835
0.0474
1.052
1.99 to 27.60
–11 Յ h Յ 12,
–13 Յ k Յ 13,
–14 Յ l Յ 13
9179
4664
0.0640
1.013
1.98 to 27.63
–12 Յ h Յ 12,
–15 Յ k Յ 14,
–26 Յ l Յ 26
19596
5242
0.1519
0.954
Refl. collected
Refl.unique
R(int)
GoF on F2
R [I Ͼ 2σ(I)]
wR (all data)
Residuals /e·Å–3
0.0441
0.1206
R1 = 0.0852
wR2 = 0.2925
1.323 and –0.582
0.0746
0.2422
0.666 and –0.271
0.406 and –0.449
Refinement method full-matrix least-squares on F2
Chem. Soc. 2002, 124, 6274–6276; e) S. Demeshko, S. Dechert,
F. Meyer, J. Am. Chem. Soc. 2004, 126, 4508–4509.
References
[1] a) J. M. Thomas, CrystEngComm 2011, 13, 4304–4306; b) D. F. [7] a) B. L. Schottel, J. Bacsa, K. R. Dunbar, Chem. Commun. 2005,
Weng, B. W. Wang, Z. M. Wang, S. Gao, CrystEngComm 2011,
13, 4683–4688; c) C. P. Price, A. L. Grzesiak, J. W. Kampf, A. J.
Matzger, Cryst. Growth Des. 2003, 3, 1021–1025.
46–47; b) O. B. Berryman, V. S. Bryantsev, D. P. Stay, D. W.
Johnson, B. P. Hay, J. Am. Chem. Soc. 2007, 129, 48–58; c) B. P.
Hay, V. S. Bryantsev, Chem. Commun. 2008, 2417–2428; d) A.
García-Raso, F. M. Albertí, J. J. Fiol, A. Tasada, M. Barceló-Oli-
ver, E. Molins, C. Estarellas, A. Frontera, D. Quinˇonero, P. M.
Deyà, Cryst. Growth Des. 2009, 9, 2363–2376; e) B. Han, J. J.
Lu, J. K. Kochi, Cryst. Growth Des. 2008, 8, 1327–1334; f) M.
Giese, M. Albrecht, G. Ivanova, A. Valkonen, K. Rissanen, Sup-
ramol. Chem. 2012, 24, 48–55.
[2] a) G. R. Desiraju, Science 1997, 278, 404–405; b) H. G. Brittain,
Polymorphism in Pharmaceutical Solids, M. Dekker, New York,
1999.
[3] P. A. Gale, M. E. Light, R. Quesada, Chem. Commun. 2005,
5864–5866.
[4] a) J. C. Ma, D. A. Dougherty, Chem. Rev. 1997, 97, 1303–1324;
b) A. Frontera, P. Gamez, M. Mascal, T. J. Mooibroek, J. Reedijk,
Angew. Chem. Int. Ed. 2011, 50, 9564–9583; c) B. P. Hay, R.
Custelcean, Cryst. Growth Des. 2009, 9, 2539–2545.
[5] a) M. A. Halcrow, J. C. Huffman, G. Christou, Angew. Chem. Int.
Ed. Engl. 1995, 34, 889–891; b) J. Ribas, A. Escuer, M. Monfort,
R. Vicente, R. Cortes, L. Lezama, T. Rojo, Coord. Chem. Rev.
1999, 193–195, 1027; c) M. M. Yu, Z. H. Ni, C. C. Zhao, A. L.
Cui, H. Z. Kou, Eur. J. Inorg. Chem. 2007, 5670–5676; d) Z. F.
Zhang, Y. B. Wu, G. S. Zhang, CrystEngcomm 2011, 13, 4496–
4499; e) I. S. Bushmarinov, O. G. Nabiev, R. G. Kostyanovsky,
M. Y. Antipin, K. A. Lyssenko, CrystEngcomm 2011, 13, 2930–
2934.
[8] B. Han, J. J. Lu, J. K. Kochi, Coord. Chem. Rev. 2011, 255, 290–
317.
[9] a) D. Choi, T. Kim, S. M. Reddy, J. Kang, Inorg. Chem. Commun.
2009, 12, 41–44; b) X. Y. Yu, H. H. Zou, L. Q. Wei, M. H. Zeng,
Inorg. Chem. Commun. 2010, 13, 1137–1139; c) A. Singh, B.
Mondal, Inorg. Chim. Acta 2010, 363, 3145–3150; d) S. Dutta,
S. Baitalik, M. Ghosh, U. Florke, K. Nag, Inorg. Chim. Acta 2011,
¯
372, 227–236.
[10] A. W. Addison, P. J. Burke, J. Heterocycl. Chem. 1981, 18, 803–
805.
[11] a) G. M. Sheldrick, SHELXTL, Version 5.1; Bruker Analytical X-
ray Instruments Inc.: Madison, WI, 1998; b) G. M. Sheldrick,
SHELXL-97, PC Version; University of Göttingen, Göttingen,
Germany, 1997.
[6] a) T. J. Mooibroek, C. A. Black, P. Gamez, J. Reedijk, Cryst.
Growth Des. 2008, 8, 1082–1093; b) P. Gamez, T. J. Mooibroek,
S. J. Teat, J. Reedijk, Acc. Chem. Res. 2007, 40, 435–444; c) I.
Alkorta, I. Rozas, J. Elguero, J. Am. Chem. Soc. 2002, 124, 8593–
8598; d) M. Mascal, A. Armstrong, M. D. Bartberger, J. Am.
Received: December 19, 2011
Published Online: June 21, 2012
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