Mercury (II), copper (II) and silver (I) complexes with ether or diether functionalized bis-NHC ligands: Synthesis and structural studies

Article abstract of DOI:10.1039/c1ce05134b

The oligoether-linked dibenzimidazolium (or diimidazolium) salts, bis[2-(3-ethylbenzimidazolium-1-yl)ethyl]ether diiodide (1), bis[2-(3- ⁿbutylbenzimidazolium-1-yl)ethyl]ether diiodide (2), 1,1′-[1,2-ethanediyl-bis(oxy-1,2-ethanediyl)]-bis(3-benzylbenzimidazolium- 1-yl) diiodide (3), 1,1′-[1,2-ethanediyl-bis(oxy-1,2-ethanediyl)]-bis(3- ethylbenzimidazolium-1-yl) di-hexafluorophosphate (4), 1,1′-[1,2- ethanediyl-bis(oxy-1,2-ethanediyl)]-bis(3-benzylimidazolium-1-yl) diiodide (5), and their five mercury(ii), copper(ii) and silver(i) complexes with ether or diether linkers mercury-{C,C′-bis[2-(3-ethylimidazolin-2-yliden-1-yl) ethyl]ether} tetraiodomercurate (7), copper-{C,C′-bis[2-(3- ⁿbutylimidazolin-2-yliden-1-yl)ethyl]ether} tetraiodomercurate (8), mercury-{C,C′-1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)] -bis(3-benzylbenzimidazolin-2-yliden-1-yl)} triiodomercurate acetate (9), silver-{C,C′-1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)] -bis(3-ethylbenzimidazolin-2-yliden-1-yl)} hexafluorophosphate (10) and mercury-{C,C′-1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)] -bis(3-benzylimidazolin-2-yliden-1-yl)} tetraiodomercurate (11), as well as one anionic complex bis[2-(3-ⁿbutylbenzimidazolium-1-yl)ethyl]ether di-μ-iodo-bis(diiodomercurate) (6) were prepared and characterized. Each of N-heterocyclic carbene metal complexes 7-11 possesses a macrometallocycle, respectively, formed by one metal atom and one bidentate chelate carbene ligand. In the crystal packing of complexes 6-11, 2D supramolecular layers are formed via intermolecular weak interactions, including π-π interactions, hydrogen bonds, C-H...π contacts and weak Hg...I bonds.

Full text of DOI:10.1039/c1ce05134b

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PAPER
Mercury(II), copper(II) and silver(I) complexes with ether or diether
functionalized bis-NHC ligands: synthesis and structural studies†
*
Qing-Xiang Liu, Jie Yu, Xiao-Jun Zhao, Shu-Weng Liu, Xiao-Qiong Yang, Kang-Ying Li
and Xiu-Guang Wang
Received 27th January 2011, Accepted 22nd March 2011
DOI: 10.1039/c1ce05134b
The oligoether-linked dibenzimidazolium (or diimidazolium) salts, bis[2-(3-ethylbenzimidazolium-1-yl)
ethyl]ether diiodide (1), bis[2-(3-nbutylbenzimidazolium-1-yl)ethyl]ether diiodide (2), 1,10-[1,2-
ethanediyl-bis(oxy-1,2-ethanediyl)]-bis(3-benzylbenzimidazolium-1-yl) diiodide (3), 1,10-[1,2-
ethanediyl-bis(oxy-1,2-ethanediyl)]-bis(3-ethylbenzimidazolium-1-yl) di-hexafluorophosphate (4), 1,10-
[1,2-ethanediyl-bis(oxy-1,2-ethanediyl)]-bis(3-benzylimidazolium-1-yl) diiodide (5), and their five
mercury(II), copper(II) and silver(I) complexes with ether or diether linkers mercury-{C,C0-bis[2-(3-
ethylimidazolin-2-yliden-1-yl)ethyl]ether} tetraiodomercurate (7), copper-{C,C0-bis[2-
(3-nbutylimidazolin-2-yliden-1-yl)ethyl]ether} tetraiodomercurate (8), mercury-{C,C0-1,10-[1,2-
ethanediylbis(oxy-1,2-ethanediyl)]-bis(3-benzylbenzimidazolin-2-yliden-1-yl)} triiodomercurate
acetate (9), silver-{C,C0-1,10-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]-bis(3-ethylbenzimidazolin-2-
yliden-1-yl)} hexafluorophosphate (10) and mercury-{C,C0-1,10-[1,2-ethanediylbis(oxy-1,2-
ethanediyl)]-bis(3-benzylimidazolin-2-yliden-1-yl)} tetraiodomercurate (11), as well as one anionic
complex bis[2-(3-nbutylbenzimidazolium-1-yl)ethyl]ether di-m-iodo-bis(diiodomercurate) (6) were
prepared and characterized. Each of N-heterocyclic carbene metal complexes 7–11 possesses
a macrometallocycle, respectively, formed by one metal atom and one bidentate chelate carbene ligand.
In the crystal packing of complexes 6–11, 2D supramolecular layers are formed via intermolecular weak
interactions, including p–p interactions, hydrogen bonds, C–H/p contacts and weak Hg/I bonds.
have played important roles in the development of the N-
Introduction
heterocyclic carbene chemistry.6 Particularly, N-heterocyclic
carbene silver(I) complexes can be used as carbene transfer
reagents to make other NHC metal complexes.7 In contrast, few
examples of the NHC copper(II) complexes have been reported
so far.8 Recently, some silver(I) and mercury(II) complexes con-
taining bidentate bis-NHC ligands with alkyl and durene linkers
have been published by us.9 As a continuation, we reported
herein the synthesis, structures and fluorescent emission spectra
of five NHC mercury(II), copper(II) and silver(I) complexes 7–11
with ether or diether linkers, as well as one anionic complex 6.
The transition metal complexes of N-heterocyclic carbenes
(NHCs) have attracted considerable interest over the past two
decades due to their structural variety and easy access through
deprotonation of N,N0-disubstituted benzimidazolium (or imi-
dazolium) salts.1 The strong s-donating ability of N-heterocyclic
carbenes lead to high stability of their metal complexes toward
heat, moisture and air. More recently, much effort has also been
devoted to the synthesis of functionalized NHC ligands and their
metal complexes.2 Among N-heterocyclic carbene ligands, some
bis-NHC ligands with bridging linkers (such as alkyl,3 aryl,4
pyridyl and lutidinyl5) have been reported, and their metal
complexes have also been investigated.
Results and discussion
As ancillary ligands, N-heterocyclic carbenes are attractive
alternative to the widely utilized phosphine ligands in organo-
metallic catalysis. The NHC silver(I) and mercury(II) complexes
Synthesis and general characterization of precursors 1–5 and
complexes 6–11
The dibenzimidazolium (or diimidazolium) salts, 1–3 and 5 were
prepared from benzimidazole (or imidazole) by stepwise alkyl-
ation with 1-iodoalkane in the presence of NaH in THF at 60 ꢀC
for 48 h, followed by quarterization with 2,20-diiododiethyl ether
or 1,2-bis(2-iodoethoxy)ethane in sequence (Scheme 1). The
precursor 4 was obtained by two steps. The first step is in
a manner analogous to that for 1, and the second step is through
Tianjin Key Laboratory of Structure and Performance for Functional
Molecule, College of Chemistry, Tianjin Normal University, Tianjin
300387, P. R. China. E-mail: qxliu@eyou.com
† CCDC reference numbers 760079, 760077, 760078, 800065, 760076 and
800066. For crystallographic data in CIF or other electronic format see
DOI: 10.1039/c1ce05134b
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Scheme 1 Preparation of precursors 1–5.
an anionic exchange with ammonium hexafluorophosphate in
methanol (method 2 in Scheme 1(1)). Precursors 1–5 are stable to
air and moisture, and show good solubility in polar organic
solvents such as DMSO, CH3CN and CH2Cl2, and almost
1
insoluble in diethyl ether and petroleum ether. In the H NMR
spectra of 1–5, the benzimidazolium (or imidazolium) proton
signals (NCHN) appear at d ¼ 9.64–11.44 ppm, which are
consistent with the chemical shifts of reported benzimidazolium
(or imidazolium) salts.2
Synthetic methods of complexes 6–11 are shown in Scheme 2.
The reaction of precursor 2 with HgI2 in DMSO/CH3CN gave an
anionic complex 6 (Scheme 2 (1)). Treatment of 1 or 5 with HgI2
in DMSO/CH3CN in the presence of KOtBu afforded NHC-
mercury(II) complexes 7 or 11, respectively (Scheme 2 (2) and
Scheme 2 (6)). The precursor 2 reacted with CuI in the presence
of KOtBu in DMSO/CH3CN in air for 24 h, then HgI2 was
added to the above suspension. After stirring for 12 h, a mixed
dinuclear NHC complex 8 was generated (Scheme 2 (3)). In the
reaction, the Cu(I) was oxidated to Cu(II) in the solution by air,
then the latter species coordinated with bidentate carbene to
form NHC-copper(II) complex, copper-{C,C0-bis[2-(3-nbutyli-
midazolin-2-yliden-1-yl)ethyl]ether} diiodide. After the addition
of HgI2, the Hg(II) coordinated with two iodine atoms in NHC-
copper(II) complex to give a mixed dinuclear complex 8. Treat-
ment of 3 with Hg(OAc)2 in DMSO/CH3CN in the presence of
KOtBu afforded a NHC-mercury(II) complex 9 (Scheme 2 (4)).
The NHC-silver(I) complex 10 was prepared by the reaction of 4
with Ag2O in CH2Cl2 (Scheme 2(5)). The complexes 6–11 are
stable to air and moisture, and soluble in DMSO, and insoluble
in diethyl ether. The NHC-silver(I) complex 10 is light-sensitive
1
Scheme 2 Preparation of complexes 6–11.
in solution, but light-stable as solid. The H NMR spectra of
1
anionic complex 6 is similar to that of precursor 2. In the H
NMR spectra of 7–11, the disappearance of the resonances for
the benzimidazolium (imidazolium) protons (NCHN) shows the
formation of the expected metal carbene complexes, and the
chemical shifts of other protons are similar to those of corre-
sponding precursors. In 13C NMR spectra of 7–9 and 11, the
signals for the carbene carbon appear at 175.8–186.1 ppm, which
are comparable to known metal carbene complexes.2 The signal
of carbene carbon in 10 was not observed. Similar results have
been reported for some NHC-silver(I) complexes, which may
result from the fluxional behaviour of the NHC complexes.10
Structures of complexes 6–11
1
The structures of complexes 6–11 were confirmed by H NMR
and 13C NMR spectroscopy, and X-ray crystallography. In NHC
metal complexes 7–11 (Fig. 2 (a)–Fig. 6 (a)), each complex
contains a macrometallocycle (10-membered ring for 7 and 8, 13-
membered ring for 9–11) constructed by one metal atom (Hg(II)
for 7, 9 and 11, Cu(II) for 8, Ag(I) for 10) and one bidentate
chelate biscarbene ligand with a flexible ether or diether chain. In
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Fig. 1 (a) Perspective view of 6 and anisotropic displacement parame-
ters depicting 30% probability. All hydrogen atoms were omitted for
ꢀ
ꢀ
clarity. Selected bond lengths (A) and angles ( ): Hg(1)–I(1) 2.6937(6), Hg
(1)–I(3A) 2.9056(5); N(1)–C(7)–N(2) 111.1(6), I(1)–Hg(1)–I(2) 115.293
(19), I(1)–Hg(1)–I(3) 111.901(18), I(3)–Hg(1)–I(3A) 91.685(15), Hg(1)–I
(3)–Hg(1A) 88.315(15). (b) 2D supramolecular layer of 6 formed by p–p
interactions and C–H/I hydrogen bonds. All hydrogen atoms except
those participating in the hydrogen bonds were omitted for clarity.
Fig. 2 (a) Perspective view of 7 and anisotropic displacement parame-
ters depicting 30% probability. All hydrogen ꢀatoms were omitted for
ꢀ
clarity. Selected bond lengths (A) and angles ( ): Hg(1)–C(9) 2.109(15),
Hg(1)–C(22) 2.091(13), Hg(1)–I(4) 3.2554(15), Hg(2)–I(4) 2.8315(14); C
(9)–Hg(1)–C(22) 158.7(5), N(1)–C(9)–N(2) 107.0(12), I(2)–Hg(2)–I(4)
111.94(5), Hg(1)–I(4)–Hg(2) 102.46(4). (b) 2D supramolecular layer of 7
formed by weak Hg/I bonds and C–H/p contacts. All hydrogen atoms
except those participating in the C–H/p contacts were omitted for
clarity.
complexes 6–11, both benzimidazole (or imidazole) rings of each
complex form the dihedral angles of 24.7–72.6ꢀ (46.9(1)ꢀ for 6,
65.6(1)ꢀ for 7, 72.6(1)ꢀ for 8, 53.1ꢀ for 9, 24.7(1)ꢀ for 10 and 47.1
(1)ꢀ for 11). In complexes 7–11, two alkyl chains of each complex
point to the opposite directions (ethyl chains for 7 and 10, butyl
chains for 8, and benzyl groups for 9 and 11). In contrast, two
butyl chains in each cationic unit of complex 6 point to the same
direction (Fig. 1 (a)). The internal ring angles (N–C–N) at the
carbene center in 7–11 are in the range of 106.2(7)–116(2)ꢀ, and
these values are consistent with those of known NHC-metal
complexes.2
The X-ray crystal structural analysis of 7 show that the Hg(1)
is tetracoordinated with two carbene carbons, one oxygen atom
and one iodine atom to adopt a distorted tetrahedral geometry.
The C(9)–Hg(1)–C(22) angle is 158.7(5)ꢀ, and the bond distances
In complex 6, the anionic unit [Hg2I6]2ꢁ is formed by two
mercury(II) atoms and six iodine atoms (two bridging iodines I(3)
and I(3A), and four non-bridging iodines I(1), I(2), I(1A), I(2A)).
The co-planar four atoms Hg(1), I(3), Hg(1A) and I(3A) form
a quadrangle Hg2I2 arrangement (I(3)–Hg(1)–I(3A) ¼ 91.685
(15)ꢀ and Hg(1)–I(3)–Hg(1A) ¼ 88.315(15)ꢀ). The four non-
bridging iodine atoms I(1), I(1A), I(2) and I(2A) lie in both sides
of the quadrangle plane (I(1)–Hg(1)–I(2) ¼ 115.293(19)ꢀ). The
distances between non-bridging iodine and mercury(II) (Hg(1)–I
of two Hg–C are 2.109(15) A and 2.091(13) A, respectively. The
ꢀ
ꢀ
ꢀ
Hg/O separation of 2.7073(1) A is within the range of distances
observed in the crown ether and polyethylene glycol complexes
of HgX2 (X ¼ Cl, Br, I).11 In anionic unit [HgI4]2ꢁ of 7, the Hg(2)
is also tetracoordinated. It is, however, surrounded by four
iodine atoms. The bond angles of six I–Hg(2)–I are in the range
of 103.98(5)–121.70(6)ꢀ, and the bond lengths of four Hg–I vary
ꢀ
ꢀ
from 2.7395(15) A to 2.8315(14) A. These values are in the
regular range. Additionally, the cationic unit and anionic unit are
linked via weak Hg(1)/I(4) bond, and Hg(1)/I(4) distance of
3.2554(15) A is longer than those of other regular Hg–I bonds
ꢀ
(2.7–2.8 A), but shorter than the sum of the van der Waals radii
ꢀ
ꢀ
(1) ¼ 2.6937(6) A and Hg(1)–I(2) ¼ 2.7160(6) A) are slightly
ꢀ
shorter than those between bridging iodine and mercury(II) (Hg
ꢀ
(1)–I(3) ¼ 2.9005(6) and Hg(1)–I(3A) ¼ 2.9056(5) A). The Hg
ꢀ
ꢀ
ꢀ
(1)/Hg(1A) separation of 4.0449(3) A shows no metal-metal
(3.7 A). The Hg(1)/Hg(2) distance of 4.7532(10) A indicates no
metal–metal interactions.
ꢀ
interactions (the van der Waals radii of mercury ¼ 1.7 A).
4088 | CrystEngComm, 2011, 13, 4086–4096
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Fig. 4 (a) Perspective view of 9 and anisotropic displacement parame-
ters depicting 30% probability. All hydrogen atoms except those
participating in the hydrogen bonds were omitted for clarity. Selected
Fig. 3 (a) Perspective view of 8 and anisotropic displacement parame-
ꢀ
ꢀ
bond lengths (A) and angles ( ): Hg(1)–C(14) 2.074(12), Hg(1)–C(27)
2.104(12), Hg(1)–O(4) 2.566(8), Hg(2)–O(4) 2.483(8), Hg(2)–I(1) 2.6747
(12); C(14)–Hg(1)–C(27) 163.0(4), C(14)–Hg(1)–O(4) 99.5(4), C(27)–Hg
(1)–O(4) 97.5(4), O(4)–Hg(2)–I(1) 100.6(2), O(4)–Hg(2)–I(2) 92.0(2), O
(4)–Hg(2)–I(3) 104.5(2), I(1)–Hg(2)–I(2) 117.94(4), C(35)–O(4)–Hg(2)
129.4(8), C(35)–O(4)–Hg(1) 96.3(7), Hg(1)–O(4)–Hg(2) 116.7(3), N(1)–C
(14)–N(2) 107.1(10), N(3)–C(27)–N(4) 108.1(10). (b) 2D supramolecular
layer of 9 formed by two types of p–p interactions. All hydrogen atoms
except those participating in the hydrogen bonds were omitted for clarity.
ters depicting 30% probability. All hydrogen atoms were omitted for
ꢀ
ꢀ
clarity. Selected bond lengths (A) and angles ( ): Cu(1)–C(7A) 2.52(3), Cu
(1)–O(1) 2.26(3), Cu(1)–I(1A) 2.970(3), Hg(1)–I(1A) 2.8660(19), Hg(1)–I
(2A) 2.7328(18); C(7A)–Cu(1)–C(7B) 162.8(13), O(1)–Cu(1)–C(7A) 81.4
(7), O(1)–Cu(1)–I(1) 128.36(6), Hg(1)–I(1A)–Cu(1) 74.01(7), I(1A)–Cu
(1)–I(1B) 103.28(13), I(1A)–Hg(1)–I(1B) 108.70(9), I(2A)–Hg(1)–I(2B)
123.63(10), N(1A)–C(7A)–N(2A) 116(2). (b) 2D supramolecular layer of
8 formed by p–p interactions and C–H/p contacts. All hydrogen atoms
except those participating in the C–H/p contacts were omitted for
clarity.
plane. The quadrangle plane and two benzimidazole rings form
the same dihedral angle of 77.2(2)ꢀ. The Cu(II) and Hg(II) are
connected via two bridging iodine atoms (Hg–I–Cu bond angle ¼
Interestingly, complex 8 is a mixed copper(II)/mercury(II)
dinuclear NHC-metal complex, in which the copper(II) center is
pentacoordinated with two carbene carbons, two iodine atoms
and one oxygen atom to adopt a slightly distorted trigonal
bipyramid geometry. The apical positions of axis are occupied by
two carbene carbon atoms with the Cu(1)–C(7A) distance of 2.52
ꢀ
ꢀ
74.01(7) ). The Cu/Hg distance of 3.5134(12) A shows weak
metal-metal interactions, and this distance is similar to that of the
Cu–Hg heteronuclear complex reported.12 The Cu(1)/O(1)
ꢀ
separation (2.26(3) A) is longer than the regular Cu–O bond
ꢀ
ꢀ
ꢀ
distance (1.9 A), however, shorter than the sum of the van der
ꢀ
Waals Radii of 3.2 A.
(3) A and C(7A)–Cu(1)–C(7B) angle of 162.8(13) . The equato-
rial plane is occupied by two bridging iodine atoms and one
oxygen atom (the I(1A)–Cu(1)–I(1B) bond angle ¼ 103.28(13)ꢀ,
13
In complex 9, both Hg(1) and Hg(2) atoms are tetracoordi-
nated. The former is surrounded by two carbene carbons and two
oxygen atoms from acetate group, and the latter is surrounded by
three iodine atoms and one oxygen atoms from acetate group.
Hg(1) and Hg(2) atoms are connected by one bridging oxygen
atom from acetate group. The C(14)–Hg(1)–C(27) angle is 163.0
ꢀ
and the Cu–I bond distance ¼ 2.970(3) A). The Hg(1) is sur-
rounded by four iodine atoms (two bridging iodine atoms I(1A)
and I(1B), and two non-bridging iodine atoms (I(2A) and I(2B))
to afford a slightly distorted tetrahedral arrangement, in which
the bond angles of six I–Hg(1)–I are in the range of 104.73(5)–
123.63(10)ꢀ. The distance between Hg(1) and non-bridging
ꢀ
ꢀ
(4) , and the distances of Hg–C bonds are 2.074(12) A and 2.104
ꢀ
iodine atom (2.7328(18) A) is slightly shorter than that between
ꢀ
(12) A, respectively. These values are comparable to the corre-
ꢀ
Hg(1) and bridging iodine atom (2.8660(19) A). These values are
sponding values in complex 7. The O(3)–Hg(1)–O(4) angle is 49.6
(3)ꢀ, and the Hg(1)–O(3) and Hg(1)–O(4) separations are 2.6638
comparable to those in the [Hg2I6]2ꢁ unit of 6. Five atoms Cu(1),
Hg(1), I(1A), I(1B) and O(1) are co-planar, and four of them (Cu
(1), Hg(1), I(1A) and I(1B)) form a quadrangle geometry. Two
non-bridging iodine atoms lie in both sides of the quadrangle
ꢀ
(8) A and 2.566(8) A, respectively. The distances between Hg(1)
ꢀ
ꢀ
and the oxygen atoms from ether chain are 3.183(1) A and 3.2632
ꢀ
(99) A, respectively, showing no Hg/O interactions (the sum of
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Fig. 5 (a) Perspective view of 10 and anisotropic displacement param-
ꢁ
eters depicting 30% probability. All hydrogen atoms and PF6 were
ꢀ
ꢀ
omitted for clarity. Selected bond lengths (A) and angles ( ): Ag(1)–C(9)
2.095(6), Ag(1)–C(22) 2.099(6); C(9)–Ag(1)–C(22) 177.5(2), N(1)–C(9)–
N(2) 107.2(5). (b) 2D supramolecular layer of 10 formed via p–p inter-
actions and C–H/p contacts. All hydrogen atoms were omitted for
clarity.
the van der Waals Radii between mercury atom and oxygen atom ¼
Fig. 6 (a) Perspective view of 11 and anisotropic displacement param-
eters depicting 30% probability. All hydrogen atoms and [HgIꢀ4]2ꢁ anion
ꢀ
3.1 A). The dihedral angle between benzene ring from benzyl group
and adjacent benzimidazole ring is 80.4(1)ꢀ. Besides, C–H/O
hydrogen bonds in 9 are observed, in which oxygen atom is from
acetate group and hydrogen atom is from CH2 of benzyl group
(Table 1).
ꢀ
were omitted for clarity. Selected bond lengths (A) and angles ( ): Hg(1)–
C(10) 2.074(8), Hg(1)–C(19) 2.055(8); C(10)–Hg(1)–C(19) 170.9(3), N
(1)–C(10)–N(2) 106.2(7), N(3)–C(19)–N(4) 106.2(7). (b) 1D chains of 11
formed by p–p interactions and C–H/I hydrogen bonds. All hydrogen
atoms except those participating in the hydrogen bonds were omitted for
clarity. (c) 2D supramolecular layer of 11 formed by C–H/I hydrogen
bonds and two types of p–p interactions. All hydrogen atoms except
those participating in the hydrogen bonds were omitted for clarity.
In the cation of 10, the C(9)–Ag(1)–C(22) array is nearly linear
with a bond angle of 177.5(2)ꢀ. The distances of two Ag–C bonds
ꢀ
ꢀ
are 2.095(6) A and 2.099(6) A, respectively. These values are
similar to those of known NHC-silver(I) complexes.6a,6b
In the molecular structure of complex 11, the Hg(1) atom is
tetracoordinated with two carbene carbon atoms and two oxygen
atoms from diether chain to form distorted tetrahedral
arrangement. The C–Hg–C is almost linear with the bond angle
of 170.9(3)ꢀ, and two Hg–C bond distances are 2.055(8) and
and dimetal-bis{C,C0-bis[2-(3-Rimidazolin-2-yliden-1-yl)ethyl]
ether} di-hexafluorophosphate (13)15 (metal ¼ silver or gold, R ¼
1-naphthylmethylene or 9-anthracenylmethylene). The confor-
mations of complexes may depend mainly on two factors,
namely, the length of ether linkers and the types of anions. When
linkers are single ether, the conformations of complexes are
mostly relative to the types of anions. In the case, if anions
ꢀ
2.074(8) A, respectively. The distances of Hg(1)–O(2) and Hg(1)–
ꢀ
ꢀ
O(1) are 2.8655(57) A and 3.0180(52) A, respectively. The dihe-
dral angle between benzene ring from benzyl group and adjacent
imidazole ring is 77.5(1)ꢀ.
a
Table 1 H-bonding geometry (A, ꢀ) for 6, 9 and 11
ꢀ
The conformations of NHC metal complexes bearing ether or
diether linkers
D–H/A
D–H
H/A
D/A
D–H/A
As shown in Scheme 3, NHC metal complexes bearing ether or
diether linkers adopt two diverse conformations, namely, single
nuclear macrocycle complex I with one bidentate chelate carbene
ligand (e.g., 7–11) and dinuclear macrocycle complex II with two
bidentate carbene ligands (e.g., disilver-bis{C,C0-bis[2-(3-methyl-
imidazolin-2-yliden-1-yl)ethyl]ether} di-tetrafluoroborate (12)14
6
9
11
C(8)–H(8)/I(1)i
C(7)–H(7A)/O(3)
C(18)–H(18)/I(1)i
C(9)–H(9)/I(2)i
0.97(1)
0.97(1)
0.93(1)
0.93(1)
3.096(1)
2.297(8)
3.156(5)
3.197(6)
3.861(2)
3.255(1)
3.942(6)
4.013(7)
136.8(3)
169.2(7)
143.4(3)
147.4(4)
a
Symmetry code: i1 ꢁx, ꢁy, ꢁz for 6. i ¼ x, 0.5 ꢁ y, 0.5 + z for 11.
4090 | CrystEngComm, 2011, 13, 4086–4096
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intermolecular benzimidazole rings, and another is from benzene
rings of benzyl group (Fig. 4 (b)).
In the crystal packing of 11, the double strand 1D supramo-
lecular chain is formed by C–H/I hydrogen bonds and p–p
stacking interactions from intermolecular imidazole rings (Fig. 6
(b)). The double strand 1D supramolecular chains are further
extended into 2D supramolecular layers through another type of
p–p stacking interactions from intermolecular benzene rings of
benzyl groups (Fig. 6 (c)).
Fluorescent emission spectra of precursors 1 and 5, and
complexes 7 and 11
Scheme 3 The two diverse conformations of NHC metal complexes.
As shown in Fig. 7, the fluorescent emission spectra of
precursors 1 and 5, and complexes 7 and 11 are obtained upon
excitation at 232 nm in acetonitrile at room temperature (the
fluorescent emission spectra of 2–4 and anionic complex 6 are
similar to that of 1, and the fluorescent emission spectra of 8–
10 are similar to that of 7). The precursors 1 and 5 show
double emission bands in the region of 330–350 nm, which can
be attributed to intraligand n–p* and p–p* transitions,
respectively. Complexes 7 and 11 show also double emission
bands at the corresponding positions of their precursors, but
the fluorescent emission of 7 and 11 are weaker than those of
precursors, which should originate from the metal perturbed
intraligand processes. Additionally, 5 and 11 exhibit weak
are PF6ꢁ or BF4ꢁ, NHC metal complexes adopt conformation II
(e.g., 12 and 13), and if anions are halide anions, NHC metal
complexes adopt conformation I (e.g., 7 and 8). When linkers are
diether, NHC metal complexes adopt conformation I (e.g., 9–
11). The other factors, such as different solvents, the size of N-
substitutents and benzimidazole (or imidazole) rings, have
probably little influence on the formation of diverse
conformations.
The crystal packing of complexes 6–11
An interesting feature in the crystal packing of 6 is that 1D
supramolecular chain is formed by the p–p stacking interactions
from intermolecular benzimidazole rings (the distances of p–p
interactions being given in Table 2).16 In addition, the anionic
building units ([Hg2I6]2ꢁ) are packed between the 1D chains to
extend 1D chains into 2D supramolecular layers via C–H/I
hydrogen bonds17 as shown in Fig. 1 (b) (Table 1).
In the crystal packing of 7 (Fig. 2 (b)), 2D supramolecular
layers are formed by cationic macrocycles and anionic unit
[HgI4]2ꢁ via weak Hg/I bonds and C–H/p contacts (the data
of C–H/p contacts being given in Table 2). In C–H/p
contacts, the hydrogen atoms are from ethyl groups.18
Analysis of the crystal packing of 8 and 10 shows that 2D
supramolecular layers are formed by p–p stacking interactions
from intermolecular benzimidazole rings and intermolecular C–
H/p contacts. In C–H/p contacts, the hydrogen atoms for 8
are from butyl groups, and the hydrogen atoms for 10 are from
ethyl groups (Fig. 3 (b) and Fig. 5 (b)).
In the crystal packing of 9, 2D supramolecular layer is formed
by two types of the p–p stacking interactions. One is from
Fig. 7 Emission spectra of 1 (-$-$), 5 (—), 7 (/) and 11 (—) at room
temperature in CH3CN (5.0 ꢂ 10ꢁ6 M) solution.
ꢀ
ꢀ
ꢀ
Table 2 Distances (A) of p–p interactions, and distances (A) and angles ( ) of C–H/p contacts for 6–11
p–p
C–H/p
H/p
Complex
Face-to-face
Center-to-center
C–H/p
6
7
8
9
10
11
3.593(2) (benzimidazole)
—
3.529(1) (benzimidazole)
3.499(1) (benzimidazole) 3.603(2) (benzene)
3.487(4)
3.736(2) (benzimidazole)
—
3.648(9) (benzimidazole)
3.556(5) (benzimidazole) 3.942(6) (benzene)
3.858(5)
—
—
2.912(6)
2.821(1)
—
3.097(3)
—
155.6(1)
154.1(3)
—
105.3(1)
—
3.329(1) (imidazole) 3.622(1) (benzene)
3.958(2) (imidazole) 3.695(1) (benzene)
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emission bands in the range of 280–300 nm, which is likely to
arise from the electronic transitions of the benzene ring.19
A solution of 1-ethylbenzimidazole (4.930 g, 33.7 mmol) and
2,20-diiododiethyl ether (5.000 g, 15.3 mmol) in THF (100 mL)
was stirred for three days under refluxing, and a pale yellow
precipitate was formed. The product was collected by filtration
and the filter cake was washed with THF. The pale yellow
powder of bis[2-(3-ethylbenzimidazolium-1-yl)ethyl]ether diio-
dide (1) was obtained. Yield: 6.710 g (71%). Mp: 172–174 ꢀC.
Anal. calcd for C22H28I2N4O: C 42.74, H 4.56, N 9.06%. Found:
Conclusions
In summary, five N-heterocyclic carbene mercury(II), copper(II)
and silver(I) complexes and one anionic complex have been
synthesized and characterized. Each of complexes 7–11
possesses a macrometallocycle, respectively, formed by one
metal atom and one bidentate chelate carbene ligand. Addi-
tionally, we have also known from these complexes in the text
and reported complexes that NHC metal complexes bearing
ether or diether linkers adopt two diverse conformations in the
solid state, namely, single nuclear macrocycle complex with one
bidentate chelate carbene ligand and dinuclear macrocycle
complex with two bidentate carbene ligands. In the crystal
packing of complexes 6–11, 2D supramolecular layers are
formed through weak intermolecular interactions including p–
p stacking interactions, hydrogen bonds, C–H/p contacts and
weak Hg/I bonds. The macrocyclic structures of these NHC
metal complexes suggest that they may have potential appli-
cations in the host–guest chemistry. Further studies on new
organometallic compounds from the precursors and analogous
ligands are under way.
1
C 42.43, H 4.62, N 9.36%. H NMR (400 MHz, DMSO-d6):
d 1.49 (t, J ¼ 5.6, 6H, CH3), 3.98 (t, J ¼ 4.2, 4H, CH2), 4.48 (q,
J ¼ 5.6, 4H, CH2), 4.68 (t, J ¼ 4.2, 4H, CH2), 7.63 (m, 4H, PhH),
7.94 (d, J ¼ 6.4, 2H, PhH), 8.05 (d, J ¼ 6.4, 2H, PhH), 9.75 (s,
2H, 2-benzimiH) (benzimi ¼ benzimidazole).
The following dibenzimidazolium (or diimidazolium) salts 2, 3
and 5 were prepared in a manner analogous to that for 1.
Preparation of bis[2-(3-nbutylbenzimidazolium-1-yl)ethyl]ether
ꢀ
diiodide (2). Yield: 4.930 g (79%). Mp: 202–204 C. Anal. calcd
for C26H36I2N4O: C 46.30, H 5.38, N 8.31%. Found: C 46.57, H
1
5.42, N 8.61%. H NMR (400 MHz, DMSO-d6): d 0.93 (t, J ¼
5.6, 6H, CH3), 1.42 (m, 4H, CH2), 2.08 (m, 4H, CH2), 3.83 (t, J ¼
4.2, 4H, CH2), 4.41 (t, J ¼ 5.6, 4H, CH2), 4.59 (t, J ¼ 4.2, 4H,
CH2), 7.70 (m, 4H, PhH), 7.90 (d, J ¼ 6.4, 2H, PhH), 8.13 (d, J ¼
6.4, 2H, PhH), 9.64 (s, 2H, 2-benzimiH).
Preparation of 1,10-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]-bis
(3-benzylbenzimidazolium-1-yl) diiodide (3). Yield: 2.548 g (80%).
Mp: 192–194 ꢀC. Anal. calcd for C34H36I2N4O2: C 51.92, H 4.61,
N 7.12%. Found: C 51.63, H 4.75, N 7.44%. 1H NMR (400 MHz,
DMSO-d6): d 3.49 (t, J ¼ 4.2, 4H, CH2), 3.80 (t, J ¼ 4.2, 4H,
CH2), 4.67 (t, J ¼ 4.2, 4H, CH2), 5.81 (s, 4H, CH2), 7.36–7.65 (m,
14H, PhH), 7.98–8.12 (m, 4H, PhH), 9.94 (s, 2H, 2-benzimiH).
Experimental
General procedures
2,20-Diiodoethyl ether and 1,2-bis(2-iodoethoxy)ethane were
prepared according to the literature methods.20 All manipula-
tions were performed using Schlenk techniques, and solvents
were purified by standard procedures. All the reagents for
synthesis and analyses were of analytical grade and used without
further purification. Melting points were determined with
Preparation of 1,10-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]-bis
a Boetius Block apparatus. H and 13C{1H} NMR spectra were
1
(3-benzylimidazolium-1-yl) diiodide (5). Yield: 2.320 g (84%). Mp:
ꢀ
107–109 C. Anal. calcd for C26H32I2N4O2: C 45.50, H 4.70, N
recorded on a Varian Mercury Vx 400 spectrometer at 400 MHz
1
8.16%. Found: C 45.86, H 4.95, N 8.53%. H NMR (400 MHz,
and 100 MHz, respectively. Chemical shifts, d, were reported in
1
ppm relative to the internal standard TMS for both H and 13C
DMSO-d6): d 3.40 (t, J ¼ 4.2, 4H, CH2), 3.63 (t, J ¼ 4.2, 4H,
CH2), 4.38 (t, J ¼ 4.2, 8H, CH2), 5.78 (s, 4H, CH2), 7.30–7.45 (m,
10H, PhH and 4, 5-imiH), 7.73–7.84 (m, 4H, PhH), 9.05 (s, 2H, 2-
imiH) (imi ¼ imidazole).
NMR, and J values were given in Hz. The elemental analyses of
all compounds were obtained from the powder compounds
recrystallised, and measured using a Perkin-Elmer 2400C
Elemental Analyzer. The luminescent spectra were conducted on
a Cary Eclipse fluorescence spectrophotometer.
Preparation of 1,10-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]-bis
(3-ethylbenzimidazolium-1-yl) di-hexafluorophosphate (4). This
compound was prepared via two steps, and the first step is in
a manner analogous to that for 1. The second step is an anionic
exchange with ammonium hexafluorophosphate: NH4PF6 (1.476
g, 9.1 mmol) was added to a methanol solution of 1,10-[1,2-
ethanediylbis(oxy-1,2-ethanediyl)]-bis(3-ethylbenzimidazolium-
1-yl) diiodide (2.000 g, 3.0 mmol) whilst stirring and a white
precipitate was formed immediately. The product was collected
by filtration and washed with small portions of cold methanol to
Preparation of dibenzimidazolium (or diimidazolium) salts
Preparation of bis[2-(3-ethylbenzimidazolium-1-yl)ethyl]ether
diiodide (1). A solution of benzimidazole (20.000 g, 0.169 mol) in
THF (100 mL) was added to a suspension of oil-free sodium
hydride (10.000 g, 50%) in THF (300 mL) and the resulted
mixture was stirred for 2 h at 60 ꢀC. Then a solution of ethyl
iodide (29.760 g, 0.186 mol) in THF (150 mL) was added drop-
wise to the above solution. The mixture was continued to stir for
ꢀ
give compound 4. Yield: 1.780 g (85%). Mp: 156–158 C. Anal.
ꢀ
12 h at 60 C and a brown solution was obtained. The solvent
calcd for C24H32F12N4O2P2: C 41.27, H 4.62, N 8.02%. Found: C
41.48, H 4.51, N 8.44%. 1H NMR (400 MHz, DMSO-d6): d 1.64
(t, J ¼ 5.5, 6H, CH3), 3.40 (t, J ¼ 4.2, 4H, CH2), 3.73 (t, J ¼ 4.2,
4H, CH2), 4.69 (t, J ¼ 4.2, 4H, CH2), 4.79 (q, J ¼ 5.5, 4H, CH2),
7.65 (m, 4H, PhH), 7.88 (d, J ¼ 6.3, 2H, PhH), 7.89 (d, J ¼ 6.3,
2H, PhH), 11.44 (s, 2H, 2-benzimiH).
was removed with a rotary evaporator and H2O (200 mL) was
added to the residue. Then the solution was extracted with
CH2Cl2 (3 ꢂ 100 mL), and the extracting solution was dried over
anhydrous MgSO4. After removing CH2Cl2, a pale yellow liquid
of 1-ethylbenzimidazole was obtained. Yield: 20.000 g (81%).
4092 | CrystEngComm, 2011, 13, 4086–4096
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Preparation of complexes 6–11
residue. The resulting solution was extracted with CH2Cl2 (3 ꢂ
20 mL), and the extracting solution was dried over anhydrous
MgSO4. After removing MgSO4 by filtration, the filtrate was
concentrated to 10 mL. Hexane (5 mL) was added to precipi-
tate ꢀa pale yellow powder of 8. Yield: 0.108 g (54%). Mp: 142–
144 C. The pale yellow powder of 8 was dissolved in DMSO,
and slow diffusion of diethyl ether into this solution led to the
formation of colourless crystals suitable for X-ray structure
analysis at room temperature, within three weeks. Anal. calcd
for C26H34CuHgI4N4O: C 26.23, H 2.88, N 4.71%. Found: C
26.52, H 2.61, N 4.84%. 1H NMR (400 MHz, DMSO-d6):
d 0.88 (t, J ¼ 5.6, 6H, CH3), 1.35 (m, 4H, CH2), 1.93 (m, 4H,
CH2), 3.96 (t, J ¼ 4.2, 4H, CH2), 4.45 (t, J ¼ 5.6, 4H, CH2),
4.67 (t, J ¼ 4.2, 4H, CH2), 7.68 (m, 4H, PhH), 7.93 (d, J ¼ 6.4,
2H, PhH), 8.05 (d, J ¼ 6.4, 2H, PhH). 13C NMR (100 MHz,
DMSO-d6): d 186.1 (Ccarbene), 133.2, 127.1, 126.0, 114.3, 113.7
and 113.2 (PhC), 69.0 (OCH2), 48.4 (NCH2), 47.1 (NCH2), 32.5
(CCH2C), 19.9 (CCH2C), 14.3 (CCH3).
Preparation of bis[2-(3-nbutylbenzimidazolium-1-yl)ethyl]ether
di-m-iodo-bis(diiodomercurate) (6). A suspension of precursor 2
(0.200 g, 0.3 mmol) and mercury(II) iodide (0.140 g, 0.7 mmol)
in DMSO (5 mL) and acetonitrile (30 mL) was stirred for 24 h
ꢀ
at 80 C, and a pale yellow solution was formed. The solution
was diluted with water (30 mL) and extracted with CH2Cl2 (3
ꢂ 20 mL). The extracting solution was dried over anhydrous
MgSO4. After removing CH2Cl2, a white powder of 6 was
obtained. Yield: 0.292 g (62%). Mp: 180–182 ꢀC. The white
powder of 6 was dissolved in DMSO, and slow diffusion of
diethyl ether into this solution led to the formation of colour-
less crystals suitable for X-ray structure analysis at room
temperature, within three weeks. Anal. calcd for
C26H36Hg2I6N4O: C 19.73, H 2.29, N 3.54%. Found: C 19.88,
1
H 2.47, N 3.34%. H NMR (400 MHz, DMSO-d6): d 0.98 (t,
J ¼ 5.6, 6H, CH3), 1.47 (m, 4H, CH2), 2.23 (m, 4H, CH2), 3.79
(t, J ¼ 4.2, 4H, CH2), 4.47 (t, J ¼ 5.6, 4H, CH2), 4.61 (t, J ¼
4.2, 4H, CH2), 7.74 (m, 4H, PhH), 7.93 (d, J ¼ 6.4, 2H, PhH),
8.18 (d, J ¼ 6.4, 2H, PhH), 9.88 (s, 2H, 2-benzimiH). 13C NMR
(100 MHz, DMSO-d6): d 138.1 (NCHN), 131.4, 126.9, 126.3,
115.1, 114.1 and 113.3 (PhC), 64.1 (OCH2), 47.3 (NCH2), 46.7
(NCH2), 33.1 (CCH2C), 18.7 (CCH2C), 13.6 (CCH3).
Preparation of mercury-{C,C0-1,10-[1,2-ethanediylbis(oxy-1,2-
ethanediyl)]-bis(3-benzylbenzimidazolin-2-yliden-1-yl)}
triiodo-
mercurate acetate (9). This complex was prepared in a manner
analogous to that for 7, only instead of mercury(II) iodide with
anhydrous mercury(II) acetate. Yield: 0.140 g (40%). Mp: 236–
ꢀ
238 C. The pale yellow powder of 9 was dissolved in DMSO,
Preparation of mercury-{C,C0-bis[2-(3-ethylimidazolin-2-yli-
den-1-yl)ethyl]ether} tetraiodomercurate (7). A suspension of
KOtBu (0.090 g, 0.8 mmol), precursor 1 (0.200 g, 0.3 mmol)
and mercury(II) iodide (0.310 g, 6.7 mmol) in DMSO (5 mL)
and slow diffusion of diethyl ether into this solution led to the
formation of pale yellow crystals suitable for X-ray structure
analysis at room temperature, within three weeks. Anal. calcd
for C36H37Hg2I3N4O4: C 31.52, H 2.72, N 4.09%. Found: C
31.83, H 2.77, N 4.12%. 1H NMR (400 MHz, DMSO-d6):
d 1.59 (s, 3H, CH3), 3.46 (t, J ¼ 4.2, 4H, CH2), 3.73 (t, J ¼ 4.2,
4H, CH2), 4.83 (t, J ¼ 4.2, 4H, CH2), 6.15 (s, 4H, CH2), 7.35–
7.41 (m, 10H, PhH), 7.56–7.62 (m, 4H, PhH), 7.78 (d, J ¼ 8.2,
2H, PhH), 8.04 (d, J ¼ 8.2, 2H, PhH). 13C NMR (100 MHz,
DMSO-d6): d 184.8 (Ccarbene), 135.9, 133.2, 129.2, 128.6, 127.7,
126.3, 114.1 and 113.6 (PhC), 70.5 and 68.2 (OCH2), 52.1 and
49.3 (NCH2), 32.1 (OCO), 26.7 (CCH3).
ꢀ
and acetonitrile (30 mL) was stirred for 24 h at 80 C. A brown
solution was formed and the solvent was removed with a rotary
evaporator. Water (30 mL) was added to the residue. Then the
solution was extracted with CH2Cl2 (3 ꢂ 20 mL). The
extracting solution was dried over anhydrous MgSO4. After
removing MgSO4 by filtration, the filtrate was concentrated to
10 mL and hexane (5 mL) was added. A pale yeꢀllow powder
was obtained. Yield: 0.220 g (54%). Mp: 212–214 C. The pale
yellow powder of 7 was dissolved in DMSO, and slow diffusion
of diethyl ether into this solution led to the formation of pale
yellow crystals suitable for X-ray structure analysis at room
temperature, within three weeks. Anal. calcd for
C22H26Hg2I4N4O: C 20.79, H 2.06, N 4.41%. Found: C 20.64,
Preparation of silver-{C,C0-1,10-[1,2-ethanediylbis(oxy-1,2-ethane-
diyl)]-bis(3-ethylbenzimidazolin-2-yliden-1-yl)} hexafluoro-
phosphate (10). A suspension of 4 (0.200 g, 0.2 mmol) and
silver oxide (0.058 g, 0.2 mmol) in dichloromethane (30 mL)
was refluxed for 24 h. The resulting mixture was filtered and
the filtrate was concentrated to 5 mL. A white powder was
precipitated after adding Et2O (5 mL). Isolation by filtration
yielded 10. Yield: 0.102 g (59%). Mp: 176–178 ꢀC. The white
powder of 10 was dissolved in DMSO and C6H12, and slow
diffusion of diethyl ether into this solution led to the formation
of colourless crystals suitable for X-ray structure analysis at
room temperature, within two weeks. Anal. calcd for
C24H30AgF6N4O2P: C 43.72, H 4.59, N 8.50%. Found: C 43.53,
1
H 2.33, N 4.62%. H NMR (400 MHz, DMSO-d6): d 1.43 (t,
J ¼ 5.6, 6H, CH3), 4.10 (t, J ¼ 4.2, 4H, CH2), 4.52 (q, J ¼ 5.6,
4H, CH2), 4.63 (t, J ¼ 4.2, 4H, CH2), 7.69 (m, 4H, PhH), 7.90
(d, J ¼ 6.4, 2H, PhH), 8.11 (d, J ¼ 6.4, 2H, PhH). 13C NMR
(100 MHz, DMSO-d6): d 180.2 (Ccarbene), 132.1, 126.2, 125.6,
114.2, 113.5 and 113.0 (PhC), 70.2 (OCH2), 48.1 (NCH2), 47.5
(NCH2), 13.6 (CCH3).
Preparation of copper-{C,C0-bis[2-(3-nbutylimidazolin-2-yliden-
1-yl)ethyl]ether} tetraiodomercurate (8). A suspension of KOtBu
(0.090 g, 0.8 mmol), precursor 2 (0.200 g, 0.3 mmol) and
anhydrous copper(I) iodide (0.129 g, 0.7 mmol) in DMSO (5
mL) and acetonitrile (20 mL) was stirred for 24 h at 80 ꢀC in
air. Then anhydrous mercury(II) iodide (0.320 g, 0.7 mmol) was
added to above brown suspension. The resulting mixture was
allowed to stir for 12 h at 80 ꢀC. The solvent was removed with
a rotary evaporator, and water (30 mL) was added to the
1
H 4.68, N 8.34%. H NMR (400 MHz, DMSO-d6): d 1.67 (t,
J ¼ 5.4, 6H, CH3), 3.40 (t, J ¼ 4.3, 4H, CH2), 3.79 (t, J ¼ 4.3,
4H, CH2), 4.74 (t, J ¼ 4.3, 4H, CH2), 4.87 (q, J ¼ 5.4, 4H,
CH2), 7.70 (m, 4H, PhH), 7.91 (d, J ¼ 6.4, 2H, PhH), 7.96 (d,
J ¼ 6.4, 2H, PhH). 13C NMR (100 MHz, DMSO-d6): d 133.2,
125.6, 124.3, 113.5, 112.7 and 110.8 (PhC), 71.1 (OCH2), 47.3
(NCH2), 46.6 (NCH2), 12.8 (CCH3). The carbene carbon was
not observed.
This journal is ª The Royal Society of Chemistry 2011
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Table 3 Summary of crystallographic data for 6–8
6
7$DMSO
8$2DMSO
Chemical formula
FW/g molꢁ1
C26H36Hg2I6N4O
C22H26Hg2I4N4O$DMSO
1349.38
Monoclinic
P21/c
11.475(3)
17.199(5)
19.604(4)
90.00
117.849(12)
90.00
3420.9(15)
4
2.620
C26H34CuHgI4N4O$2DMSO
1583.17
Orthorhombic
Pccn
13.4814(9)
15.3581(11)
19.0334(13)
90.00
90.00
90.00
3940.8(5)
4
2.668
1346.56
Monoclinic
C2/c
20.465(6)
11.488(4)
19.833(9)
90.00
115.192(4)
90.00
4219(3)
4
2.120
Crystal system
Space group
ꢀ
a/A
ꢀ
b/A
ꢀ
c/A
a/ꢀ
b/ꢀ
g/ꢀ
3
ꢀ
V/A
Z
Dcalcd/Mg mꢁ3
m/mmꢁ1
F(000)
12.506
2824
12.662
2432
7.197
2524
Crystal sizꢀe/mm
T/K
0.20 ꢂ 0.18 ꢂ 0.16
2.14, 25.00
296(2)
0.24 ꢂ 0.22 ꢂ 0.16
1.67, 25.03
296(2)
0.23 ꢂ 0.22 ꢂ 0.20
2.09, 25.01
296(2)
qmin, qmax
/
No. of data collected
No. of unique data
Rint
18567
3479
0.0276
178
0.981
16489
6044
0.1456
373
1.002
10069
3695
0.0528
208
1.059
No. of refined parameters
Goodness-of-fit on F2
a
Final R indicesb [I > 2s(I)]
R1
0.0283
0.0627
0.0807
0.1920
0.0753
0.1843
wR2
R indices (all data)
R1
wR2
0.0382
0.0679
0.1002
0.2077
0.1232
0.2161
a
b
2
2
GOF ¼ [Su(Fo ꢁ Fc )2/(n ꢁ p)]1/2, where n is the number of reflection and p is the number of parameters refined. R1 ¼ S(kFo| ꢁ |Fck)/S|Fo|; wR2 ¼ 1/
[s2(Fo2) + (0.0691P) + 1.4100P] where P ¼ (Fo2 + 2Fc )/3.
2
Table 4 Summary of crystallographic data for 9–11
9$0.5H2O
10$0.5C6H12
11$0.5DMSO
Chemical formula
FW/g molꢁ1
C36H37Hg2I3N4O4$0.5H2O
1380.58
Triclinic
C24H30AgF6N4O2P$0.5C6H12
701.44
Triclinic
ꢁ
P1
8.0951(12)
12.3444(18)
15.870(2)
108.903(3)
94.498(3)
102.542(2)
1445.4(4)
2
C26H30Hg2I4N4O2$0.5DMSO
1378.38
Monoclinic
P21/c
13.5458(8)
18.2469(11)
16.9521(10)
90.00
111.1540(10)
90.00
3907.7(4)
4
2.343
Crystal system
Space group
ꢁ
P1
ꢀ
a/A
11.510(2)
11.811(2)
15.423(3)
84.823(3)
87.271(3)
81.578(3)
2064.3(6)
2
ꢀ
b/A
ꢀ
c/A
a/ꢀ
b/ꢀ
g/ꢀ
3
ꢀ
V/A
Z
Dcalcd/Mg mꢁ3
m/mmꢁ1
F(000)
2.220
9.713
1272.0
1.612
0.824
716
11.063
2492
Crystal sizꢀe/mm
T/K
0.38 ꢂ 0.36 ꢂ 0.30
1.75, 25.03
296(2)
0.24 ꢂ 0.20 ꢂ 0.18
1.37, 25.03
296(2)
0.28 ꢂ 0.26 ꢂ 0.20
1.61, 25.03
296(2)
qmin, qmax
/
No. of data collected
No. of unique data
Rint
10 580
7288
0.0395
452
1.028
7347
5118
0.0272
372
1.045
19 742
6891
0.0317
380
1.039
No. of refined parameters
Goodness-of-fit on F2
a
Final R indicesb [I > 2s(I)]
R1
0.0618
0.1653
0.0560
0.1384
0.0331
0.0859
wR2
R indices (all data)
R1
wR2
0.0801
0.1789
0.0983
0.1667
0.0497
0.0931
a
b
2
2
GOF ¼ [Su(Fo ꢁ Fc )2/(n ꢁ p)]1/2, where n is the number of reflection and p is the number of parameters refined. R1 ¼ S(kFo| ꢁ |Fck)/S|Fo|; wR2 ¼ 1/
[s2(Fo2) + (0.0691P) + 1.4100P] where P ¼ (Fo2 + 2Fc )/3.
2
4094 | CrystEngComm, 2011, 13, 4086–4096
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Preparation of mercury-{C,C0-1,10-[1,2-ethanediylbis(oxy-1,2-
ethanediyl)]-bis(3-benzylimidazolin-2-yliden-1-yl)} tetraiodo-
and E. Peris, Chem. Rev., 2009, 109, 3677–3707; (f) J. C. Y. Lin,
R. T. W. Huang, C. S. Lee, A. Bhattacharyya, W. S. Hwang and
I. J. B. Lin, Chem. Rev., 2009, 109, 3561–3598; (g) D. Gnanamgari,
E. L. O. Sauer, N. D. Schley, C. Butler, C. D. Incarvito and
R. H. Crabtree, Organometallics, 2009, 28, 321–325; (h)
W. J. Sommer and M. Weck, Coord. Chem. Rev., 2007, 251, 860–
873; (i) L. Ray, S. Barman, M. M. Shaikh and P. Ghosh, Chem.–
Eur. J., 2008, 14, 6646–6655; (j) H. V. Huynh, C. Holtgrewe,
T. Pape, L. L. Koh and F. E. Hahn, Organometallics, 2006, 25,
245–249; (k) F. E. Hahn, M. C. Jahnke and T. Pape,
Organometallics, 2007, 26, 150–154.
3 (a) C. Marshall, M. F. Ward and W. T. A. Harrison, J. Organomet.
Chem., 2005, 690, 3970–3975; (b) H. Clavier, J. C. Guillemin and
M. Mauduit, Chirality, 2007, 19, 471–476; (c) M. S. Jeletic,
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26, 5267–5270; (d) L. G. Bonnet, R. E. Douthwaite and
R. Hodgson, Organometallics, 2003, 22, 4384–4386; (e) F. E. Hahn
and M. Foth, J. Organomet. Chem., 1999, 585, 241–245; (f)
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E. Peris, J. W. Faller and R. H. Crabtree, Organometallics, 2004,
23, 1253–1263.
mercurate (11). This complex was prepared in a manner analo-
ꢀ
gous to that for 7. Yield: 0.168 g (41%). Mp: 138–140 C. The
pale yellow powder of 6 was dissolved in DMSO, and slow
diffusion of diethyl ether into this solution led to the formation of
pale yellow crystals suitable for X-ray structure analysis at
room temperature, within three weeks. Anal. calcd for
C26H30Hg2I4N4O2: C 23.32, H 2.26, N 4.18%. Found: C 23.76, H
1
2.13, N 4.38%. H NMR (400 MHz, DMSO-d6): d 3.36 (t, J ¼
4.2, 4H, CH2), 3.59 (t, J ¼ 4.2, 4H, CH2), 4.33 (t, J ¼ 4.2, 4H,
CH2), 5.76 (s, 4H, CH2), 7.32–7.38 (m, 10H, PhH and 4,5-imiH),
7.75–7.80 (m, 4H, PhH). 13C NMR (100 MHz, DMSO-d6):
d 175.8 (Ccarbene), 136.6, 129.5, 128.7 and 124.7 (PhC and imiC),
70.5 and 69.5 (OCH2), 54.2 and 52.1 (NCH2).
X-Ray data collection and structure determinations. X-Ray
single-crystal diffraction data for complexes 6–11 were collected
by using a Bruker Apex II CCD diffractometer at 296(2) K with
Mo-Ka radiation (l ¼ 0.71073 M) by u scan mode. There was no
evidence of crystal decay during data collection in all cases.
Semiempirical absorption corrections were applied by using
SADABS and the program SAINT was used for integration of
the diffraction profiles.21 All structures were solved by direct
methods by using the SHELXS program of the SHELXTL
package and refined with SHELXL22 by the full-matrix least-
squares methods with anisotropic thermal parameters for all
non-hydrogen atoms on F2. Hydrogen atoms bonded to C atoms
were placed geometrically and presumably solvent H atoms were
first located in difference Fourier maps and then fixed in the
calculated sites. Further details for crystallographic data and
structural analysis are listed in Table 3 and Table 4. Figures were
generated by using Crystal-Maker.23
4 (a) W. L. Duan, M. Shi and G. B. Rong, Chem. Commun., 2003, 2916–
2917; (b) A. R. Chianese and R. H. Crabtree, Organometallics, 2005,
24, 4432–4436; (c) B. P. Morgan, G. A. Galdamez, R. J. Gilliard Jr
and R. C. Smith, Dalton Trans., 2009, 2020–2028; (d)
A. A. Danopoulos, A. A. D. Tulloch, S. Winston, G. Eastham and
M. B. Hursthouse, Dalton Trans., 2003, 1009–1015.
5 (a) B. Liu, W. Chen and S. Jin, Organometallics, 2007, 26, 3660–3667;
(b) D. H. Brown, G. L. Nealon, P. V. Simpson, B. W. Skelton and
Z. Wang, Organometallics, 2009, 28, 1965–1968; (c) A. T. Normand
and K. J. Cavell, Eur. J. Inorg. Chem., 2008, 2781–2800; (d)
F. E. Hahn, M. C. Jahnke, V. Gomez-Benitez, D. Morales-Morales
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6 (a) J. C. Garrison and W. J. Youngs, Chem. Rev., 2005, 105, 3978–
4008; (b) Q. X. Liu, F. B. Xu, Q. S. Li, X. S. Zeng, X. B. Leng,
Y. L. Chou and Z. Z. Zhang, Organometallics, 2003, 22, 309–314;
ꢂ
ꢂ
(c) A. Caballero, E. Dıez-Barra, F. A. Jalon, S. Merino and
J. Tejeda, J. Organomet. Chem., 2001, 395, 617–618; (d) Q. X. Liu,
L. N. Yin and J. C. Feng, J. Organomet. Chem., 2007, 692, 3655–
€
3663; (e) T. Weskamp, V. P. W. Bohm and W. A. Herrmann, J.
Organomet. Chem., 2000, 600, 12–22.
7 (a) A. A. D. Tulloch, A. A. Danopoulos, S. Winston, S. Kleinhenz
and G. Eastham, J. Chem. Soc., Dalton Trans., 2000, 4499–4506; (b)
I. J. B. Lin and C. S. Vasam, Coord. Chem. Rev., 2007, 251, 642–
670; (c) K. J. Cavell, D. J. Nielsen, B. W. Sketon and A. H. White,
Organometallics, 2006, 25, 4850–4856; (d) A. Rit, T. Pape and
F. E. Hahn, J. Am. Chem. Soc., 2010, 132, 4572–4573.
In the crystal structure of 7, the solvent molecule DMSO is
disordered in two positions with the occupancy factors of 0.70
ꢀ
and 0.30. The C–S and S–O distances were restrained to 1.79 A
ꢀ
and 1.45 A, respectively. The displacement parameters of
8 (a) P. L. Arnold, M. Rodden, K. M. Davis, A. Scarisbrick, A. J. Blake
and C. Wilson, Chem. Commun., 2004, 1612–1613; (b) A. O. Larsen,
W. Leu, C. Nieto-Oberhuber, J. E. Campbell and A. H. Hoveyda,
J. Am. Chem. Soc., 2004, 126, 11130–11131; (c) J. Yun, D. Kim and
H. Yun, Chem. Commun., 2005, 5181–5183.
disordered atoms were refined with isotropy.
Acknowledgements
9 (a) Q. X. Liu, S. J. Li, X. J. Zhao, Y. Zang, H. B. Song, J. H. Guo and
X. G. Wang, Eur. J. Inorg. Chem., 2010, 983–988; (b) Q. X. Liu,
X. Q. Yang, X. J. Zhao, S. S. Ge, S. W. Liu, Y. Zang, H. B. Song,
J. H. Guo and X. G. Wang, CrystEngComm, 2010, 12, 2245–2255;
(c) Q. X. Liu, A. H. Chen, X. J. Zhao, Y. Zang, X. M. Wu,
X. G. Wang and J. H. Guo, CrystEngComm, 2011, 13, 293–305.
10 (a) A. A. D. Tulloch, A. A. Danopoulos, S. Winston, S. Kleinhenz
and G. Eastham, J. Chem. Soc., Dalton Trans., 2000, 4499–4506; (b)
C. K. Lee, K. M. Lee and I. J. B. Lin, Organometallics, 2002, 21,
10–12.
This work was financially supported by the National Science
Foundation of China (project grant no. 20872111) and the
Natural Science Foundation of Tianjin (07JCYBJC00300).
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