Synthesis, crystal structures and photoluminescence of mercury(II) complexes with two homologous novel functional rigid ligands

Article abstract of DOI:10.1002/ejic.200500439

Two novel functional rigid ligands, 2,2′- and 4,4′-bipyridyl- based "building blocks", 9-ethyl-3,6-bis[2-(4-pyridyl)ethenyl] carbazole (L¹) and 9-ethyl-3,6-bis[2-(2-pyridyl)ethenyl]-carbazole (L²), were synthesized. Treatment of L^1,2 as "building blocks" with Hg(SCN)₂ or HgI₂ afforded helixes, macrocycles, and chains, which can be further self-assembled by a π-π stacking interaction, hydrogen bond, and interatomic force in the solid state to form two-dimensional networks. In complexes 1-4, Hg^II centers all adopt four-coordination modes in different coordination environments, but they present different architectures with slightly adjusted structures of the ligands and counteranions, indicating that the nature of the ligand and anion plays an important role in the coordination networks. The luminescent properties of compounds 1-4 have been studied. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.

Full text of DOI:10.1002/ejic.200500439

FULL PAPER
DOI: 10.1002/ejic.200500439
Synthesis, Crystal Structures and Photoluminescence of Mercury(II) Complexes
with Two Homologous Novel Functional Rigid Ligands
[
a,b]
[a,c,d]
[a]
[a]
Hong-Ping Zhou,
Yu-Peng Tian,*
Jie-Ying Wu, Ju-Zhou Zhang,
[
a]
[a]
[a]
[c]
[c]
Dong-Mei Li, Yong-Min Zhu, Zhang-Jun Hu, Xu-Tang Tao, Min-Hua Jiang, and
Yi Xie*[
b]
Keywords: Mercury / Functional rigid ligands / X-ray diffraction / Luminescence
Two novel functional rigid ligands, 2,2Ј- and 4,4Ј-bipyridyl-
modes in different coordination environments, but they pres-
ent different architectures with slightly adjusted structures of
based “building blocks”, 9-ethyl-3,6-bis[2-(4-pyridyl)ethen-
1
yl]carbazole (L ) and 9-ethyl-3,6-bis[2-(2-pyridyl)ethenyl]- the ligands and counteranions, indicating that the nature of
2
1,2
carbazole (L ), were synthesized. Treatment of L as “build-
ing blocks” with Hg(SCN) or HgI afforded helixes, macro-
the ligand and anion plays an important role in the coordina-
tion networks. The luminescent properties of compounds 1–
4 have been studied.
2
2
cycles, and chains, which can be further self-assembled by a
π–π stacking interaction, hydrogen bond, and interatomic
force in the solid state to form two-dimensional networks. In
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
II
complexes 1–4, Hg centers all adopt four-coordination
Introduction
some organic ligands with special functionality for supra-
molecular architectures and functional compounds, because
of synthetic difficulties, have been reported rarely to date.
On the other hand, carbazole compounds, as is well
known, exhibit good hole transporting properties and their
charge transporting complexes can create free carriers in the
visible region through the photocarrier generation pro-
In the past decade, more and more attention has been
focused on the crystal design and engineering of multidi-
mensional arrays and networks containing metal ions as
nodes because of the potential application of such molecu-
lar materials in catalysis, electronics, molecular sensing,
[
1,2]
magnetic devices, and porous and nanosize materials.
[
5]
cess.
Recently, carbazole-containing compounds have
The rational design and construction of metal–organic
frameworks, with their fascinating structures and potential
properties, continues to attract interest in current supramo-
been extensively studied for the application of an electrolu-
minescent (EL) device and fabrication of light-emitting di-
[
6]
odes (LED) because of their sufficient hole/electron trans-
porting and luminescent properties. However, the devices
are mostly organic compounds or polymers, and the low
melting points or low decomposition temperatures inhibit
their applications. Functionalization of the organic mole-
cule (addition of donor atoms, e.g. N or O) to allow incor-
poration into inorganic/organic coordination complexes
can offer the advantages of high thermal stability and sol-
vent resistance compared to all-organic materials. So we
have tried to design and synthesize functional ligands 9-
[
3]
lecular chemistry. Up to now, extensive studies have been
carried out to give many novel one- (1D), two- (2D), and
three-dimensional (3D) frameworks based on the assembly
of metal salts with rigid N,NЈ- donor ligands, such as 4,4Ј-
bipyridine or 2,2Ј-bipyridine and their derivatives. Bridging
bis(pyridyl) ligands are often used in the construction of
metal-containing macromolecules, and the geometry of the
bis(pyridyl) ligand can define the primary structure of the
self-assembled macromolecule through metal-coordination,
hydrogen bonds and π–π stacking interactions.[ However,
4]
1
ethyl-3,6-bis[2-(4-pyridyl)ethenyl]carbazole (L ) and 9-
2
ethyl-3,6-bis[2-(2-pyridyl)ethenyl]carbazole (L ). Interest-
[
[
a] Department of Chemistry, Anhui University,
Hefei 230039, P.R. China
ingly, by the careful design of rigid ligands containing car-
bazole cores and bipyridyl, we were able to obtain com-
plexes with functionally different structures. Furthermore,
mercury() complexes have been extensively studied be-
cause of their structural diversities and attractive optical
properties such as photoluminescence and nonlinear optical
E-mail: yptian@ahu.edu.cn
b] Department of Chemistry, University of Science and Technol-
ogy of China,
Hefei 230026, P.R. China
E-mail: yxie@ustc.edu.cn
[
[
c] State Key Laboratory of Crystal Materials, Shandong Univer-
sity,
Jinan 250100, P.R. China
[7]
effects. In this article, we present a series of mercury()
d] State Key Laboratory of Coordination Chemistry, Nanjing
University,
1
complexes containing the new functional rigid ligands L
2
Nanjing 210093, P.R. China
and L (Scheme 1). Slightly adjusting the structure of the
4976
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Mercury() Complexes with Novel Functional Rigid Ligands
FULL PAPER
1
2
Scheme 1. Synthesis of ligands L , L .
[7]
ligands and counteranions gives potential changes to form gle of 120° and a metal node with an angle of 90°. Thus,
1
2
different architectures. Here the syntheses, structures, pho- the reaction of L and L with Hg(SCN) and HgI was
2
2
toluminescence and high thermal stability properties of anticipated to afford 1-D, 2-D, and 3-D structures bearing
mercury() complexes are reported.
metallacyclic or metallamacrocyclic analogous structures.
The reaction of equimolar amounts of the bis(pyridine)
1
2
ligands L and L (Scheme 1) and mercury() halide or sul-
focyanate gave the corresponding complexes 1–4. These
compounds were isolated as analytically pure, air-stable,
yellow or red solids that are very sparingly soluble in com-
mon organic solvents such as chloroform, dichloromethane,
and tetrahydrofuran. Complexes 1–4 were characterized by
X-ray structure determinations.
Results and Discussion
All of the compounds are stable in air and insoluble in
water or in common organic solvents. High yields of the
products indicate that these compounds are thermodynami-
cally stable under the prevailing reaction conditions. IR
spectra of the same counteranion compounds are similar,
1
compounds 1 and 3 showing strong absorption bands at Crystal Structure of [HgL (SCN) ] (1)
2
n
–
1
about 2065 and 2061 cm respectively that are diagnostic
of coordinated sulfocyan; middle absorption bands at about
By the slow diffusion of MeOH solution of Hg(SCN)2
1
into a solution of L in CH Cl , red crystalline 1 was ob-
2
2
–
1
4
19 and 420 cm respectively that are the Hg–N stretching
1
tained. Its formulation, [Hg(L )(SCN) ] , was confirmed by
2
n
frequencies; and middle absorption bands at about 327 and
elemental analysis and the use of the single-crystal X-ray
diffraction method. The X-ray structural analysis revealed
the formation of single-stranded helical chain structures.
–
1
3
28 cm respectively that are the Hg–S stretching fre-
quencies. Compounds 2 and 4 show middle absorption
–
1
bands at about 420 and 419 cm respectively that are the
II
Each Hg center exhibits a distorted tetrahedral coordina-
Hg–N stretching frequencies and strong absorption bands
1
tion geometry with two pyridines from L and two sulfur
–
1
at about 151 cm that are the Hg–I stretching frequencies.
atoms of Hg(SCN) as anticipated (Figure 1, a). The bond
2
angles around the mercury atom are in the range 98.67(14)–
1
27.06(6)°, indicating a quite distorted tetrahedral geome-
Crystal Structures
try. The coordinated pyridine rings are perpendicularly
In many previous examples, the HgII cation was found twisted relative to each other, presumably to minimize the
to act as a tetrahedral node with a coordination angle of steric hindrance between them.
[
7]
about 90° to generate 1-D, 2-D, and 3-D structures. It has
It is shown in part a of Figure 1 that the ligand takes
recently been reported that macrocycles, polymers, or sheets on the cis-conformation in this structure to connect two
II
resulted from the reaction of a pyridine spacer with an an- crystallographically different Hg ions. Two pyridine rings
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Yu.-P. Tian, Y. Xie et al.
FULL PAPER
a pair consisting of the Hg(SCN) unit and the ligand. As
2
depicted in part b of Figure 1, a fairly flattened, loose helix
runs along the b axis with a pitch of about 7.99 Å (distance
between the two mercury centers at the same phase); at the
widest point the diameter of the helix equals 16.03 Å. Left-
handed helicates connect through an intermolecular π–π
stacking interaction between phenyl and pyridine rings with
the short distance of 3.38 Å, and there is some evidence of
a weak interaction between each nitrogen atom of Hg(SCN)
and the pyridyl C–H group of a molecule in an adjacent
chain (C–H···N = 3.24 Å); right-handed helicates also
2
[
4]
connect in this way (Figure 1, c). Unlike most double-heli-
[
9]
cal complexes, the adjacent left-handed and neighboring
right-handed helical chains are not entangled together but
interact through π–π stacking interactions with the short
distance of 3.24 Å as illustrated in Figure 1 (parts b and c),
which may contribute to stabilizing the formation of the
helical structure. Then a two-dimensional network is
formed through the C–H···N hydrogen bond interaction es-
tablished between ligands and thiocyanate anions of adja-
cent chains and intermolecular π–π stacking interactions.
Because left-handed and right-handed helical chains coexist
in the crystal structure, the whole crystal is mesomeric and
does not exhibit chirality.
1
Crystal Structure of Hg(L ) I (2)
2
2
1
The crystal contains individual Hg(L ) I neutral mole-
2
2
cules. A perspective drawing with atom-labeling scheme is
shown in Figure 2 (a). Each metal atom is tetracoordinated
by two N donors from different ligands and two terminal
iodine atoms of HgI . The Hg–N distance (Table 1) in the
2
complex is in the range of those found in the other com-
[
7]
plexes; Hg–I distances are also in the range of those found
II
[7]
in other Hg iodine complexes with terminal Hg–I bonds.
The bond angles N(2A)–Hg(1)–N(2), N(2A)–Hg(1)–I(1),
N(2)–Hg(1)–I(1) and I(1)–Hg(1)–I(1A) are 76.3(3),
105.10(2), 106.74(2) and 139.18(3)°, respectively. Table 1
shows that the Hg–N and Hg–I distances are almost equal;
thus the strong distortion in the tetrahedral environment of
the four donor atoms is explained on the basis of strong
1
stereo interactions between the two L ligands in each com-
plex.
However, in crystal complex 2, the ligand with two po-
tential coordination nitrogen atoms, only one pyridine ni-
trogen atom of the ligand participates, coordinating to mer-
cury(). It does not present helices like the reported 2,2Ј-
and 4,4Ј-bipyridyl-based “building block” compounds be-
fore. It is possible that the large volume of two iodine atoms
repulses the ligands to form the very small angle of N–Hg–
Figure 1. (a) Molecular structure of 1 showing different coordina-
II
tion environments of the two structurally independent Hg ions.
(
b) Space-filling plots of the right-handed chain (left), left-handed
chain (right), and the ball-and-stick plot (middle) of the double
helix bridged by a π–π stacking interaction in complex 1. (c) Mol- N [76.3(3)°], which produces strong stereo interactions
ecular packing of complex 1.
II
when Hg ions bridge ligands to form the coordination
polymer. The adjacent molecules are stacked to sheets
are connected by Hg(1) to adopt the same orientation, through π–π interaction along the b axis with the short dis-
while those connected by Hg(1A) take on the opposite ori- tance of 3.44 Å, and opposite sheets interact through pair-
entation. This connectivity extends the span of the two li- wise C–H···I contacts [C–H···I = 3.92 Å, H···I = 3.16 Å][
gands and forces a turn in the chain. Such an arrangement along the c axis, which have 2D sheets propagated as de-
endows the chain structure with an intrinsic helical sense. picted in Figure 2 (b). Taking the van der Waals radii of H
The repeating unit in this single-stranded helix consists of and I to be 1.20 and 2.15 Å, respectively, any H···I contact
4]
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Mercury() Complexes with Novel Functional Rigid Ligands
FULL PAPER
The importance of such C–H···I hydrogen bonds in supra-
molecular self-assembly has also been reported recently.[
The overall structure is compact with small cavities.
8]
2
Crystal Structure of Hg (L ) (SCN) (3)
2
2
4
The structure of complex 3 is shown in Figure 3 (a). The
molecules of 3 exist as a centrosymmetric 30-membered
2
macrometallacyclic ring formed by two L ligands bridging
II
two Hg ions with pyridine nitrogen in trans-form. How-
ever, the macrocycle 3 is nonplanar and its cavity is large
[N(2)–N(3A) = 12.713 Å, Hg(1)–Hg(1A) = 12.122 Å]; the
dihedral angles between the pyridyl and carbazolyl rings,
and the neighboring pyridyl ring are 31.6° and 20.2°,
respectively. The opposite carbazolyl rings and pyridyl rings
are parallel to each other.
Figure 2. (a) Molecular structure and atom numbering of Hg-
1
(
L )
2
I
2
. The thermal ellipsoids are drawn at the 50% probability
level. (b) Molecular packing of complex 2.
Table 1. Selected intra- and intermolecular bond lengths [Å] and
angles [°] for 1–4.
1
Hg(1)–N(2) 2.354(4)
Hg(1)–N(3) 2.299(4)
N(3)–Hg(1)–N(2)
S(2)–Hg(1)–S(1)
N(2)–Hg(1)–S(2)
N(3)–Hg(1)–S(2)
N(3)–Hg(1)–S(1)
N(2)–Hg(1)–S(1)
98.67(2)
127.06(6)
101.00(1)
107.89(1)
113.72(1)
103.49(1)
Hg(1)–S(2)
Hg(1)–S(1)
2.4371(2)
2.4493(2)
2
Hg(1)–N(2) 2.425(6)
N(2)–Hg(1)–N(2A)
I(1)–Hg(1)–I(1A)
N(2A)–Hg(1)–I(1A)
N(2)–Hg(1)–I(1A)
76.3(3)
139.18(3)
106.74(2)
105.10(2)
Hg(1)–I(1)
2.6339(6)
3
Hg(1)–N(2) 2.449(3)
Hg(1)–N(3) 2.336(4)
N(3)–Hg(1)–N(2)
S(1)–Hg(1)–S(2)
N(2)–Hg(1)–S(1)
N(3)–Hg(1)–S(1)
N(2)–Hg(1)–S(2)
N(3)–Hg(1)–S(2)
95.77(1)
126.19(5)
101.63(1)
117.23(9)
103.30(9)
106.70(9)
Hg(1)–S(1)
Hg(1)–S(2)
2.4510(2)
2.460(2)
4
Hg(1)–N(2) 2.381(1)
Hg(1)–N(3) 2.447(1)
N(3)–Hg(1)–N(2)
I(2)–Hg(1)–I(1)
N(2)–Hg(1)–I(1)
N(3)–Hg(1)–I(2)
N(3)–Hg(1)–I(1)
N(2)–Hg(1)–I(2)
99.2(4)
128.51(6)
104.9(3)
103.5(3)
106.9(2)
110.1(2)
Hg(1)–I(2)
Hg(1)–I(1)
2.670(3)
2.674(2)
Figure 3. (a) Perspective view of the 30-membered macrometallacy-
clic ring of complex 3. (b) The packing diagram of complex 3 show-
ing π–π stacking interaction and the weak C–H···N interactions
along the b axis. (c) The packing diagram of complex 3 between
different chains showing the weak Hg···N interactions along the c
less than 3.35 Å and C–H···I angle Ͼ130° may therefore
potentially be considered significant.[ In complex 2, the
distance of H···I is 3.16 Å and the C–H···I angle is 152°,
8]
which indicate the formation of C–H···I hydrogen bonds. axis.
Eur. J. Inorg. Chem. 2005, 4976–4984
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Yu.-P. Tian, Y. Xie et al.
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2
In this complex, the L ligand has bidentate coordina-
II
tion, and each Hg center is coordinated by two pyridine
nitrogen atoms from two different ligands and two sulfur
atoms from two thiocyanate anions, showing a distorted tet-
rahedron geometry with a N–Hg–N bond angle of
95.77(1)°. The bond lengths of Hg–Nav of 2.39 Å and Hg–
Sav of 2.455 Å fall within the expected values (Table 1). The
dinuclear structures connect to each other through a π–π
stacking interaction (the shortest distance of two macro-
cycles is 2.85 Å) and weak C–H···N interactions (C–H···N
[
4]
=
3.45 Å) to form an infinite chain of macrocycles like a
stair structure along the b axis (Figure 3, b). In particular,
the difference chains (Figure 3, c) show some weak interac-
tion through single, secondary Hg···N–C–S interactions
(Hg···N = 3.59 Å) along the a axis. Together, the π–π stack-
ing interaction and hydrogen bond form the overall two-
dimensional network.
2
Crystal Structure of [HgL I ] (4)
2
n
Helical structures represent a longstanding synthetic tar-
get for the supramolecular chemist because of their intrinsic
[
9]
aesthetic appeal and potentially exploitable properties. At
this time, our attempts are directed toward the generation
of a helical chain through the variation of the anion while
maintaining the metal ion and ligand structure. The most
striking feature of compound 4 is the interesting arrange-
2
ment of L molecules and usual coordination of mercury
atoms forming a unique helical structure. As described in
Figure 4 (a), complex 4 also contains a pair of HgI units
2
2
and two L ligands in its asymmetric unit cell. However,
these components do not connect to another to form a
macrocyclic structure like complex 3, but rather connect to
form an infinite polymeric chain structure. A compact sin-
gle-stranded helical chain is formed by self-assembly of
2
[
HgL I ] by coordination of meta-related peripheral pyri-
2
II
dine-N of this unit to the neighboring Hg center running
along a crystallographic 2 axis in the a direction with a
1
long pitch of about 11.69 Å; at the widest point the dia-
meter of the helix equals 6.13 Å.
In addition, like complex 1,[ the adjacent helical chains
in compound 4, one exhibiting left-handedness and the
other right-handedness, are not entangled together but in-
teract through π–π stacking interactions (the shortest dis-
tance of pyridyl and benzyl rings is 3.42 Å), which are alter-
natively offered by two helical chains to generate a compact
double-stranded helical chain (Figure 4, b). To illustrate
this clearly, the left- and right-handed helical chains are rep-
resented in Figure 4, b. Like complex 1, these double-
stranded helical chains are further extended into the two-
dimensional architecture by C–H···I hydrogen bond interac-
tions established between ligands and iodine anions of adja-
cent chains (C–H···I = 4.14 Å, H···I = 3.23 Å)[ with inter-
7]
4]
actions along the b axis in compound 4 (Figure 4, c). In Figure 4. (a) Molecule structure of 4 showing different coordina-
II
tion environments of the two structurally independent Hg ions.
complex 4, the distance of H···I is 3.23 Å and the C–H···I
angle is 142°, which indicate the formation of C–H···I hy-
drogen bonds. Because left-handed and right-handed helical
(
b) Space-filling plots of the right-handed chain (left), left-handed
chain (right), and the ball-and-stick plot (middle) of the double
helix bridged by a π–π stacking interaction in complex 4. (c) Mol-
chains coexist in the crystal structure, the whole crystal is ecular packing of 4 viewed along the b axis by intermolecular hy-
drogen bond C–H···I.
mesomeric and does not exhibit chirality.
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Mercury() Complexes with Novel Functional Rigid Ligands
FULL PAPER
II
In the present work, four different Hg coordination Luminescent Properties
1
2
complexes 1–4 with bis(pyridyl) ligands (L , L ) have been
prepared and structurally characterized, giving metal–or-
ganic supramolecular architectures. Although compared
with rigid bridging ligands, flexible bridging ligands are able
to produce some unique frameworks with aesthetics and
useful properties because of their flexibility and conforma-
Luminescent transition-metal complexes containing
multichromophoric ligands with extended conjugation have
been extensively studied in recent years, partly because of
their potential use as sensors, probes, and photonic de-
[11]
vices.
Owing to the ability to affect the emission wave-
length of organic materials, syntheses of inorganic–organic
coordination complexes by the judicious choice of organic
spacers and transition-metal centers can be an efficient
method for obtaining new types of electroluminescent mate-
[
10]
tional freedom,
we designed and synthesized two novel
functional rigid ligands with long conjugated chains that
also present flexibility and conformational freedom to a
II
certain extent. In complexes 1–4, Hg centers all adopt
[12]
1
2
rials. Free ligands L and L , and their metal complexes
–4 show emission in solid state at room temperature (Fig-
four-coordination modes in different coordination environ-
ments. By comparing the structures of the four complexes,
it is clear that the conformations of ligands in the com-
plexes are related to the position of the nitrogen atom. Al-
though complexes 1 and 3 have the same mercury() cation
and thiocyanate counterion, ligand L of 4-N atoms in
complex 1 takes on the cis-conformation to form helical
chains and ligand L of 2-N atoms in complex 3 takes on
the trans-conformation to form the macrometallacyclic
ring; otherwise, ligand L of 4-N atoms in complex 1 and
ligand L of 2-N atoms in complex 4 all take on the cis-
conformation to form similar helical chains with nearly uni-
form bond lengths and angles (Table 1). Also, it should be
1
ure 5). The nanosecond range of lifetime in the solid state
at 298 K reveals that the emission is fluorescent in nature.
The solid-state fluorescent analyses show that complexes
exhibit different properties. As shown in Figure 5 (a), com-
plex 1 exhibits an intense broad emission band centered at
1
608 nm, which is completely invariant to the excitation over
2
the range of 300 to 534 nm and complex 2 always displays
a weak broad emission band centered at 604 nm upon exci-
tation over the range of 300 to 543 nm. These fluorescent
emissions can be tentatively assigned to the ligand-to-metal
charge transfer (LMCT), as two emissions at 452 and
1
2
5
22 nm upon excitation over the range of 300–428 nm can
1
noted that although L , with two potential coordination ni-
1
be observed for the free L . Complex 3 exhibits a broad
trogen atoms but only one pyridine nitrogen atom of the
ligand, coordinates to mercury() in complex 2, it is pos-
sible that the very small angle of N–Hg–N [76.3(3)°] pro-
duces strong stereo repulsion. This indicates that the con-
formations of ligands in the complexes may play an impor-
tant role, indicating that the nature of the ligand is a de-
termining factor in controlling the structural topology of
these metal–organic supramolecular architectures, which
offers the opportunity to control the coordination networks
by ligand modifications.
Characterization
Thermogravimetric Analysis
The TG-DSC measurements of complexes 1–4 were de-
termined in the range of 20–800 °C under nitrogen. To
study the thermal stability of compounds 1–4, thermal
gravimetric analyses (TGA) were performed on the single
crystal samples. TG data show that 1 is stable up to
2
35.2 °C, loses weight from 235.2 to 474 °C corresponding
1
to decomposition of ligand L , and finally loses weight from
57 to 764 °C corresponding to the losses of Hg(SCN) . The
5
2
TG data of 2 show that it is also stable up to 250 °C and
then keeps losing weight from 250 °C to 768 °C, corre-
1
sponding to decomposition of ligand L and HgI . The TG
2
data for 3 show that it begins to decompose at 197 °C, then
there are two weight-loss stages in the ranges 197–481 °C
and 530–775 °C, corresponding to decomposition of ligand
2
L and the losses of Hg(SCN) , respectively. The TG data
2
of 4 show that the weight loss from 192 to 292 °C corre-
2
sponds to the losses of ligand L , and the weight loss from
2
Figure 5. Solid-state emission spectra of complexes at room tem-
perature: (a) L , 1, and 2; (b) L , 3 and 4.
1
2
92 to 520 °C corresponds to decomposition of HgI2.
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Yu.-P. Tian, Y. Xie et al.
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intense emission band at 528 nm with a shoulder at 484 nm Fourier syntheses. The final refinement was performed by full-ma-
trix least-squares methods with anisotropic thermal parameters for
non-hydrogen atoms on F . The hydrogen atoms were added theo-
retically and riding on the concerned atoms. Crystallographic crys-
tal data and processing parameters for compounds 1–4 are shown
upon excitation over the range of 365–477 nm, which can
be tentatively assigned to LMCT and the intraligand fluo-
rescent emission. However, complex 4 presents a sharp
weak emission band with the maximum at 477 nm, which
2
in Table 2. Selected bond lengths and bond angles are listed in
is completely invariant to the excitation over the range of
Table 1.
300–429 nm. The emission spectrum in complex 4 is largely
CCDC-245193 (for 1), -245192 (for 2), -241585 (for 3), and -241588
for 4) contain the supplementary crystallographic data for this pa-
characteristic of the intraligand fluorescent emission, as two
emissions at 448 and 467 nm upon excitation over the range
(
2
per. These data can be obtained free of charge from The Cam-
bridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
of 300 to 423 nm can be observed for the free L . Thus the
difference in the intense emission results from the different
II
–
–
coordinated counteranions to Hg (I for 2, 4 and SCN
for 1, 3), which suggests that the change of counteranions
Preparation of 9-Ethyl-3,6-diiodocarbazole: 9-Ethylcarbazole (10 g,
51 mmol) and anhydrous ethanol (150 mL) were added to a three-
necked flask equipped with a magnetic stirrer, a reflux condenser,
and an isobaric dropping funnel. ICl (20 g, 123 mmol)/ethanol
[
13]
has an important effect on their fluorescent property.
(
20 mL) was added to the mixture at 80 °C. The reaction mixture
Experimental Section
was refluxed for 2 h, cooled to room temperature and filtered. The
All chemicals and solvents were dried and purified by the usual
methods. Elemental analyses were performed with a Perkin–Elmer
grey needle crystals (20.52 g, 45.9 mmol) obtained (90%) were
1
washed with ethanol. M.p. 154–155 °C. H NMR (600 MHz, [D
6
]-
2
40C elemental analyzer. IR spectra were recorded with a Nicolet
DMSO): δ = 1.27 (t, J = 6.6 Hz, 3 H), 4.41 (q, J = 6.6 Hz, 2 H),
7.50 (d, J = 8.4 Hz, 2 H), 7.74 (d, J = 8.4 Hz, 2 H), 8.61 (s, 2 H).
–1
FTIR Nexus 870 instrument in the range 4000–400 cm by using
KBr pellets. The far-IR spectra (600–50 cm ) were recorded as Nu-
jol mulls between polyethylene sheets. H and C NMR spectra
were performed on a Bruker av600 MHz Ultrashield spectrometer
and are reported as parts per million (ppm) from TMS (δ). The
thermal behaviors were recorded with a Perkin–Elmer Pris-1
–1
1
Preparation of 9-Ethyl-3,6-bis[2-(4-pyridyl)ethenyl]carbazole (L ): 9-
1
13
Ethyl-3,6-diiodocarbazole (3.13 g, 7 mmol), potassium carbonate
(
7
(
2.42 g, 17.5 mmol), tetra-n-butylammonium bromide (2.26 g,
mmol), tri-o-tolylphosphane (0.21 g, 0.7 mmol), 4-vinylpyridine
4 mL, 30 mmol), palladium() acetate (0.047 g, 0.2 mmol) and re-
–1
2
DMDA-V1 analyzer in N at a heating rate of 5 °Cmin . The lu-
distilled N,N-dimethylformamide (7 mL) under nitrogen were
added to a three-necked flask equipped with a magnetic stirrer, a
reflux condenser and a nitrogen input tube. The reaction mixture
was refluxed in an oil bath at 100 °C under nitrogen. The resulting
solution was refluxed for 48 h and then cooled to room tempera-
ture. The residue was extracted with dichloromethane (600 mL),
washed three times with distilled water, and dried with anhydrous
magnesium sulfate. Then it was filtered and concentrated. The re-
sulting solution was chromatographed over 200 g of silica gel. Elu-
tion with ethyl acetate and the recrystallization from ethanol pro-
minescent spectra were measured on single crystals at room tem-
perature using a Fluorolog-3-TAU steady-state/lifetime spectro-
fluorometer. The excitation slit was 2 nm, and the emission slit was
2
nm also.
X-ray Crystallography: Single-crystal X-ray diffraction measure-
ments were carried out on a Bruker Smart 1000 CCD dif-
fractometer equipped with a graphite crystal monochromator situ-
ated in the incident beam for data collection at room temperature.
The determination of unit cell parameters and data collections were
performed with Mo-K
α
radiation (λ = 0.71073 Å). Unit cell dimen-
duced light yellow crystals. Yield: 1.99 g (71%). M.p. 247.1–
1
sions were obtained with least-squares refinements, and all struc-
tures were solved by direct methods using SHELXL-97.[ The
other non-hydrogen atoms were located in successive difference
247.4 °C. H NMR (600 MHz, [D
6
]DMSO): δ = 1.35 (t, J = 6.9 Hz,
14]
3 H), 4.49 (q, J = 6.9 Hz, 2 H), 7.29 (d, J = 16.3 Hz, 2 H), 7.59 (d,
J = 4.8 Hz, 4 H), 7.69 (d, J = 8.4 Hz, 2 H), 7.74 (d, J = 16.3 Hz,
Table 2. Crystallographic data and structure refinement summary for complexes 1–4.
Complex
1
2
3
4
Empirical formula
Formula mass
Crystal system
Space group
a [Å]
b [Å]
c [Å]
C
718.24
monoclinic
P2
8.2569(1)
15.978(2)
21.205(3)
91.673(2)
2796.4(7)
4
30
H
23HgN
5
S
2
C
56
H
46HgI
2
N
6
C
60
H
46Hg
2
N
10
S
4
C
855.88
monoclinic
1
P2 /c
8.468(9)
23.28(3)
13.933(2)
98.012(2)
2719(5)
4
28 2 3
H23HgI N
1257.38
monoclinic
C2/c
34.732(7)
8.4181(2)
16.785(3)
98.698(3)
4851.0(17)
4
1436.49
monoclinic
P2 /n
15.919(1)
8.119(6)
21.663(2)
103.640(1)
2721(3)
2
1
/c
1
β [°] 3
V [Å ]
Z
D
–
3
calcd [gcm ]
1.706
1.996
1.753
2.091
θ range [°]
1.92–25.03
14504
4940
2.37–25.03
12284
4257
1.44–25.03
13838
4811
1.72–25.02
11579
4613
Total no. of data
No. of unique data
No. of parameters refined
343
295
343
307
R
wR
Gof
1
0.0332
0.0686
1.006
0.0407
0.0917
1.015
0.0270
0.0630
1.002
0.0574
0.1347
1.002
2
4982
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2005, 4976–4984

Mercury() Complexes with Novel Functional Rigid Ligands
H), 7.83 (d, J = 8.4 Hz, 2 H), 8.52 (s, 2 H), 8.55 (d, J = 4.8 Hz, 4
FULL PAPER
2
Acknowledgments
13
H). C NMR (600 MHz, [D
1
3
6
]DMSO): δ = 150.43, 145.34, 140.83,
34.51, 128.16, 126.11, 123.63, 123.12, 121.06, 119.97, 110.32,
7.81, 14.31. IR (KBr): ν˜ = 2927 (m), 2860 (w), 1729 (m), 1627
We thank the National Natural Science Foundation of China
50272001, 50335050, 50532030), and Person with Ability Founda-
tion of Anhui Province 2002Z021. We also wish to thank Prof.
D. Q. Wang of University of Liao Cheng for his assistance with the
X-ray structure determinations.
(
(m), 1600 (s), 1485 (m), 1413 (w), 1344 (m), 1233 (m), 1155 (w),
1
126 (w), 1022 (w), 960 (m), 805 (m), 705 (m), 591 (w), 525 (w)
–
1
cm . C28
23 3
H N (401.50): calcd. C 83.76, H 5.77, N 10. 47; found
C 83.80, H 5.76, N 10.44.
2
Preparation of 9-Ethyl-3,6-bis[2-(2-pyridyl)ethenyl]carbazole (L ): 9-
[
1] a) J. S. Evans, R. L. Musselman, Inorg. Chem. 2004, 43, 5613–
5629; b) Z. Q. Qin, M. C. Jennings, R. J. Puddephatt, Inorg.
Chem. 2001, 40, 6220–6228; c) B. Moulton, M. J. Zaworotko,
Chem. Rev. 2001, 101, 1629–1658; d) K. Kim, Chem. Soc. Rev.
Ethyl-3,6-diiodocarbazole (3.13 g, 7 mmol), potassium carbonate
(
7
2.42 g, 17.5 mmol), tetra-n-butylammonium bromide (2.26 g,
mmol), and 2-vinylpyridine (4 mL, 30 mmol) were dissolved in
redistilled N,N-dimethylformamide (7 mL). Palladium() acetate
0.047 g, 0.2 mmol) and tri-o-tolylphosphane (0.21 g, 0.7 mmol)
were added to it. The resulting solution was refluxed for 5 days
and then cooled to room temperature. The residue was extracted
with dichloromethane (600 mL), washed three times with distilled
water, and dried with anhydrous magnesium sulfate. Then it was
filtered and concentrated. The resulting solution was chromato-
graphed over silica gel (200 g). Elution with ethyl acetate/petroleum
ether (2:1) and the recrystallization from ethyl acetate produced
light yellow crystals. Yield: 1.88 g (67%). M.p. 189.3–189.4 °C. H
]DMSO): δ = 1.35 (t, J = 7.2 Hz, 3 H), 4.48
q, J = 7.2 Hz, 2 H), 7.24 (t, J = 6.0 Hz, 2 H), 7.36 (d, J = 16.2 Hz,
H), 7.57 (d, J = 7.2 Hz, 2 H), 7.66 (d, J = 7.2 Hz, 2 H), 7.80 (q,
H), 7.87 (d, J = 16.2 Hz, 2 H), 8.55 (s, 2 H), 8.59 (d, J = 4.2 Hz, 2
]DMSO): δ = 155.59, 149.50, 140.21,
36.81, 133.11, 127.87, 125.58, 125.44, 122.76, 121.91, 121.87,
19.53, 109.74, 37.31, 13.84. IR (KBr): ν˜ = 2933 (m), 2866 (w), [3] a) S. K. Ghosh, P. K. Bharadwaj, Inorg. Chem. 2004, 43, 2293–
2
002, 31, 96–107; e) S. Sailaja, M. Rajasekharan, Inorg. Chem.
003, 42, 5675–5684.
2
(
[
2] a) M. L. Tong, X. M. Chen, B. H. Ye, L. N. Ji, Angew. Chem.
Int. Ed. 1999, 38, 2237–2240; b) M. Eddaoudi, H. Li, O. M.
Yaghi, J. Am. Chem. Soc. 2000, 122, 1391–1397; c) K. S. Min,
M. P. Suh, J. Am. Chem. Soc. 2000, 122, 6834–6840; d) J. Y.
Lu, A. M. Babb, Inorg. Chem. 2001, 40, 3261–3262; e) A. Fu,
X. Huang, J. Li, T. Yuen, C. L. Lin, Chem. Eur. J. 2002, 8,
2239–2247; f) M. L. Tong, Y. M. Wu, J. Ru, X. M. Chen, S.
Kitagawa, Inorg. Chem. 2002, 41, 4846–4848; g) D. M. Shin,
I. S. Lee, Y. K. Chung, Inorg. Chem. 2003, 42, 8838–8848; h)
X. H. Bu, Y. B. Xie, J. R. Li, R. H. Zhang, Inorg. Chem. 2003,
1
NMR (600 MHz, [D
6
4
2, 7422–7430; i) T. J. Burchell, D. J. Eisler, R. J. Puddephatt,
(
Inorg. Chem. 2004, 43, 5550–5557; j) S. Mukhopadhyay, P. B.
Chatterjee, D. Mandal, G. Mostafa, A. Caneschi, J. V. Slag-
eren, T. J. R. Weakley, M. Chaudhury, Inorg. Chem. 2004, 43,
2
4
13
H). C NMR (600 MHz, [D
6
3
413–3420; k) H. Zheng, H. B. Song, M. Du, Sh. T. Chen,
1
1
1
X. H. Bu, Inorg. Chem. 2004, 43, 931–944.
733 (m), 1626 (m), 1590 (s), 1488 (m), 1412 (w), 1385 (m), 1347
w), 1236 (m), 1193 (w), 1160 (w), 1124 (w), 970 (m), 810 (m), 597
2298; b) T. P. Losier, M. J. Zaworotko, Angew. Chem. Int. Ed.
Engl. 1996, 35, 2779–2782; c) K. N. Power, L. Hennigar, M. J.
Zaworotko, Chem. Commun. 1998, 595–596; d) P. J. Hagrman,
D. Hagrman, J. Zubieta, Angew. Chem. Int. Ed. 1999, 38, 2638–
(
(
1
–
1
w), 520 (w) cm . C28
23 3
H N (401.50): calcd. C 83.76, H 5.77, N
[15]
0.47; found C 83.72, H 5.78, N 10.50.
2
684; e) Z. Q. Qin, M. C. Jennings, R. J. Puddephatt, Inorg.
1
(1): L1 (40.01 mg, 0.1 mmol) in
Preparation of [HgL (SCN)
CH Cl solution (5 mL) was layered onto a solution of Hg(SCN)
31.6 mg, 0.1 mmol) in MeOH (5 mL) and stood for several days
to give red single crystals of 1. Yield 64.64 mg (90%). IR: ν˜ = 2065
vs), 419 (m), 327 (m). C30 23HgN (718.24): calcd. C 50.17, H
.23, N 9.75; found C 50.14, H 3.24, N 9.77.
2
]
n
Chem. 2002, 41, 5174–5186; f) T. Akutagawa, T. Nakamura,
Coord. Chem. Rev. 2003, 226, 3–81; g) Y. B. Dong, P. Wang,
R. Q. Huang, Inorg. Chem. 2004, 43, 4727–4739.
2
2
2
(
[
4] a) A. M. Beatty, Coord. Chem. Rev. 2003, 246, 131–143; b)
H. W. Roesky, M. Andruh, Coord. Chem. Rev. 2003, 236, 91–
(
H
5 2
S
119.
3
[
5] H. J. Hoegl, Phys. Chem. 1965, 69, 755–759.
Preparation of Hg(L1)
solution (5 mL) was layered onto a solution of HgI
0
(2): L1 (40.01 mg, 0.1 mmol) in CHCl
(45.4 mg,
.1 mmol) in MeOH (10 mL) and stood for a week to give yellow
single crystals of 2. Yield 111.91 mg (89%). IR: ν˜ = 420 (m), 151
s). C56 46HgI (1257.38): calcd. C 53.49, H 3.69, N 6.68; found
C 53.51, H 3.68, N 6.69.
Preparation of Hg (SCN)
(L2)
Hg(SCN) (31.6 mg, 0.1 mmol) were dissolved in MeOH (20 mL),
[6] a) M. He, R. J. Twieg, U. Gubler, D. Wright, W. E. Moerner,
Chem. Mater. 2003, 15, 1156–1164; b) K. R. Justin Thomas,
J. T. Lin, Y. T. Tao, Ch. H. Chuen, Chem. Mater. 2002, 14,
2
I
2
3
2
3852–3859; c) B. Liu, L. W. Yu, Y. H. Lai, W. Huang, Chem.
Mater. 2001, 13, 1984–1991; d) Ch. W. Ko, Y. T. Tao, J. T. Lin,
K. R. Justin Thomas, Chem. Mater. 2002, 14, 357–361; e) H.
Chun, I. K. Moon, D. H. Shin, N. Kim, Chem. Mater. 2001,
(
H
2 6
N
1
3, 2818–2823.
(3): L2 (40.01 mg, 0.1 mmol) and
4
2
2
[
7] a) Ch. Y. Su, A. M. Goforth, M. D. Smith, H. C. Z. Loye, In-
org. Chem. 2003, 42, 5685–5692; b) T. J. Burchell, D. J. Eisler,
R. J. Puddephatt, Inorg. Chem. 2004, 43, 5550–5557.
2
refluxed for 2 h at 70 °C, and cooled to give a clear yellow solution.
Yellow crystals suitable for X-ray diffraction were obtained after
two weeks by slow evaporation of the methanol solution at room
temperature. Yield 57.46 mg (80%). IR: ν˜ = 2061 (vs), 420 (m), 328
[8] a) C. J. Horn, A. J. Blake, N. R. Champness, A. Garau, V. Lip-
polis, C. Wilson, M. Schröder, Chem. Commun. 2003, 312–313;
b) L. Y. Kong, Zh. H. Zhang, T. A. Okamura, M. J. Fei, W. Y.
Sun, N. Ueyama, Chem. Lett. 2004, 12, 1572–1573.
(m). C60
2 10 4
H46Hg N S (1436.49): calcd. C 50.17, H 3.23, N 9.75;
[
9] a) P. A. Maggard, C. L. Stern, K. R. Poeppelmeier, J. Am.
Chem. Soc. 2001, 123, 7742–7743; b) Z. Shi, S. H. Feng, S.
Gao, L. R. Zhang, G. Y. Yang, J. Hua, Angew. Chem. Int. Ed.
found C 50.14, H 3.24, N 9.77.
Preparation of [HgL2I (4): L2 (40.01 mg, 0.1 mmol) and HgI
2 n 2
]
2
000, 39, 2325–2326; c) C. Z. Lu, C. D. Wu, S. F. Lu, J. C. Liu,
(31.6 mg, 0.1 mmol) were dissolved in MeOH (20 mL), refluxed for
Q. J. Wu, Q. J. Hui, H. H. Zhuang, J. S. Huang, Chem. Com-
mun. 2002, 152–153; d) Y. Wang, J. H. Yu, M. Guo, R. R. Xu,
Angew. Chem. Int. Ed. 2003, 42, 4089–4092; e) M. C. Hong,
W. P. Su, R. Cao, M. Fujita, J. X. Lu, Chem. Eur. J. 2000, 6,
2
h at 70 °C, and cooled to room temperature giving a clear yellow
solution. Pale yellow crystals suitable for X-ray diffraction were
obtained after several days by slow evaporation of the methanol
solution at room temperature. Yield 77.89 mg (91%). IR: ν˜ = 419
4
27–431; f) X. H. Bu, H. Liu, M. Du, L. Zhang, Y. M. Guo,
(m), 151 (s). C28
H23HgI
2
N
3
(855.88): calcd. C 39.29, H 2.71, N
M. Shionoya, J. Ribas, Inorg. Chem. 2002, 41, 5634–5634; g) J.
Vinje, J. A. Parkinson, P. J. Sadler, T. Brown, E. Sletten, Chem.
4.91; found C 39.28, H 2.72, N 4.92.
Eur. J. Inorg. Chem. 2005, 4976–4984
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4983

Yu.-P. Tian, Y. Xie et al.
FULL PAPER
Eur. J. 2003, 9, 1620–1630; h) Z. Wu, Q. Chen, S. Xiong, B.
Xin, Z. Zhao, L. Jiang, J. S. Ma, Angew. Chem. Int. Ed. 2003,
[12] a) D. M. Ciurtin, N. G. Pschirer, M. D. Smith, U. H. F. Bunz,
H. C. zur Loye, Chem. Mater. 2001, 13, 2743–2745; b) E. Cari-
ati, X. Bu, P. C. Ford, Chem. Mater. 2000, 12, 3385–3391; c) F.
Würthner, A. Sautter, Chem. Commun. 2000, 445–446.
[13] Y. Q. Gong, R. H. Wang, Y. F. Zhou, D. Q. Yuan, M. Ch.
Hong, J. Mol. Struct. 2005, 705, 29–33.
[14] G. M. Sheldrick, SHELXL-97, Program for Crystal Structures
Refinement, University of Göttingen, Göttingen, Germany,
1997.
4
2, 3271–3274; i) M. Barboiu, G. Vaughan, R. Graff, J. M.
Lehn, J. Am. Chem. Soc. 2003, 125, 10256–10265.
[
10] a) M. Du, X. H. Bu, Z. Huang, S. T. Chen, Y. M. Gao, Inorg.
Chem. 2003, 42, 552–559; b) X. H. Bu, W. Chen, S. T. Lu, R. H.
Zhamg, D. Z. Liao, W. M. Bu, M. Shionoya, F. Brisse, J. Ribas,
Angew. Chem. Int. Ed. 2001, 40, 3201–3203; c) F. A. Paz, Y. Z.
Khimyak, A. D. Bond, J. Rocha, J. Klinowski, Eur. J. Inorg.
Chem. 2002, 2823–2828; d) Y. B. Dong, M. D. Smith, R. C.
Layland, H. C. zur Loye, Inorg. Chem. 1999, 38, 5027–5033.
11] a) Sh.-Sh. Sun, A. J. Lees, Coord. Chem. Rev. 2002, 230, 170–
[15] H. P. Zhou, J. Zh. Zhang, D. M. Li, Y. M. Zhu, Zh. J. Hu, J. Y.
Wu, Y. Xie, M. H. Jiang, X. T. Tao, Y. P. Tian, J. Mol. Struct.
2005, 743, 93–97.
[
191; b) V. Balzani, A. Juris, M. Venturi, S. Campagna, S. Ser-
Received: May 16, 2005
roni, Chem. Rev. 1996, 96, 759–834.
Published Online: October 27, 2005
4984
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2005, 4976–4984