Coordination chemistry of anticrowns: Complexation of cyclic trimeric perfluoro-o-phenylenemercury with nitro compounds

Article abstract of DOI:10.1016/j.jorganchem.2006.10.048

Cyclic trimeric perfluoro-o-phenylenemercury (o-C₆F₄Hg)₃ (1) is capable of reacting with nitromethane to give complex {[(o-C₆F₄Hg)₃](CH₃NO₂)} (2) containing one molecule of the nitro compound per one macrocycle molecule. In this complex, the nitromethane ligand is bound to 1 by its both oxygen atoms, one of which is simultaneously coordinated to all three Hg centres of the macrocycle while the other interacts with a single Hg centre. The complex of similar composition, {[(o-C₆F₄Hg)₃](C₆H₅NO₂)} (3), is produced in the interaction of 1 with nitrobenzene. In this complex too, the both oxygen atoms of the nitro group are involved in the bonding to the macrocycle. A distinctive feature of 3 is that here one oxygen atom of the coordinated nitro derivative is bound by only two Hg centres of 1 whereas the other interacts again with a single Hg site. The reaction of 1 with 5-nitroacenaphthene affords a 1:1 complex, {[(o-C₆F₄Hg)₃](C₁₂H₉NO₂)} (4), having a polydecker sandwich structure in the crystal. Unlike in 3, the aromatic rings of the nitroarene units in 4 are disposed virtually in parallel to the macrocycles. The nitro compound in 4 behaves again as a bidentate ligand, forming three Hg-O bonds with one of the adjacent macrocycles and a single Hg-O bond with another molecule of 1. The complex is characterized also by shortened Hg-C contacts between the Hg centres of 1 and the carbon atoms of the nitroarene moiety as well as shortened C-C contacts between the carbon atoms of the nitroarene and the macrocycle. In the interaction of 1 with 1-nitropyrene, complexes of two compositions, viz. {[(o-C₆F₄Hg)₃](C₁₆H₉NO₂)} (5) and {[(o-C₆F₄Hg)₃](C₁₆H₉NO₂)₃} (6) are formed. An X-ray diffraction study of 6 has shown that in this adduct two of three coordinated molecules of the nitro compound are located on one side of the metallacycle plane while the third nitroarene molecule is disposed on its other side. The aromatic rings of all three nitropyrene ligands in 6 are practically parallel to the mean plane of the macrocycle. In contrast to 2-4, each molecule of the nitroarene in 6 is bonded to 1 by a single oxygen atom which is coordinated only to one Hg centre. In the case of one of the nitropyrene ligands that forms much longer Hg-O bond with 1 than two others, an additional contribution to the bonding is made by shortened Hg-C contacts between the macrocycle and the carbon atoms of the aromatic pyrene core and also by shortened C-C contacts between the carbon atoms of the coordinated nitroarene and 1. The synthesized adducts are the first examples of complexes of an anticrown with nitro compounds.

Full text of DOI:10.1016/j.jorganchem.2006.10.048

Journal of Organometallic Chemistry 692 (2007) 953–962
www.elsevier.com/locate/jorganchem
Coordination chemistry of anticrowns: Complexation of cyclic trimeric
perfluoro-o-phenylenemercury with nitro compounds
a
a
a
a
a
I.A. Tikhonova , K.I. Tugashov , F.M. Dolgushin , A.A. Yakovenko , P.V. Petrovskii ,
b
c
a,
*
G.G. Furin , A.P. Zaraisky , V.B. Shur
a
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, Moscow 119991, Russia
b
N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences,
Academician Lavrent’ev Avenue 9, Novosibirsk 630090, Russia
c
L.M. Litvinenko Institute of Physical Organic Chemistry and Coal Chemistry, National Academy of Sciences of Ukraine,
R. Luxembourg Street 70, Donetsk 83114, Ukraine
Received 9 June 2006; received in revised form 19 October 2006; accepted 23 October 2006
Available online 10 November 2006
Abstract
Cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 (1) is capable of reacting with nitromethane to give complex {[(o-
C6F4Hg)3](CH3NO2)} (2) containing one molecule of the nitro compound per one macrocycle molecule. In this complex, the nitrometh-
ane ligand is bound to 1 by its both oxygen atoms, one of which is simultaneously coordinated to all three Hg centres of the macrocycle
while the other interacts with a single Hg centre. The complex of similar composition, {[(o-C6F4Hg)3](C6H5NO2)} (3), is produced in the
interaction of 1 with nitrobenzene. In this complex too, the both oxygen atoms of the nitro group are involved in the bonding to the
macrocycle. A distinctive feature of 3 is that here one oxygen atom of the coordinated nitro derivative is bound by only two Hg centres
of 1 whereas the other interacts again with a single Hg site. The reaction of 1 with 5-nitroacenaphthene affords a 1:1 complex, {[(o-
C6F4Hg)3](C12H9NO2)} (4), having a polydecker sandwich structure in the crystal. Unlike in 3, the aromatic rings of the nitroarene units
in 4 are disposed virtually in parallel to the macrocycles. The nitro compound in 4 behaves again as a bidentate ligand, forming three Hg–
O bonds with one of the adjacent macrocycles and a single Hg–O bond with another molecule of 1. The complex is characterized also by
shortened Hg–C contacts between the Hg centres of 1 and the carbon atoms of the nitroarene moiety as well as shortened C–C contacts
between the carbon atoms of the nitroarene and the macrocycle. In the interaction of 1 with 1-nitropyrene, complexes of two compo-
sitions, viz. {[(o-C6F4Hg)3](C16H9NO2)} (5) and {[(o-C6F4Hg)3](C16H9NO2)3} (6) are formed. An X-ray diffraction study of 6 has shown
that in this adduct two of three coordinated molecules of the nitro compound are located on one side of the metallacycle plane while the
third nitroarene molecule is disposed on its other side. The aromatic rings of all three nitropyrene ligands in 6 are practically parallel to
the mean plane of the macrocycle. In contrast to 2–4, each molecule of the nitroarene in 6 is bonded to 1 by a single oxygen atom which is
coordinated only to one Hg centre. In the case of one of the nitropyrene ligands that forms much longer Hg–O bond with 1 than two
others, an additional contribution to the bonding is made by shortened Hg–C contacts between the macrocycle and the carbon atoms of
the aromatic pyrene core and also by shortened C–C contacts between the carbon atoms of the coordinated nitroarene and 1. The syn-
thesized adducts are the first examples of complexes of an anticrown with nitro compounds.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Anticrowns; Complexes; Macrocyclic multidentate Lewis acids; Mercury; Nitro compounds; Polymercuramacrocycles
1. Introduction
Over the last two decades, there has been a rapid pro-
gress in host–guest chemistry of macrocyclic multidentate
*
Corresponding author. Tel.: +7 495 135 5024; fax: +7 495 135 5085.
Lewis acids named anticrowns [1] because of their
E-mail address: vbshur@ineos.ac.ru (V.B. Shur).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.10.048

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I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
charge-reverse analogy with crown ethers and related com-
pounds (see e.g. reviews [2a–f] and recent papers [3a–o]).
The majority of studies in this important area has been
conducted on polymercuramacrocycles which proved to
be very efficient hosts for binding various anionic and neu-
tral Lewis basic guests. The possibility of using such mac-
rocycles in catalysis [2a–c,3e] and as ionophores for ion-
selective electrodes [2b,3d] has also been demonstrated.
As part of our ongoing research into binding and catalytic
properties of anticrowns, we have previously described a ser-
ies of complexes of cyclic trimeric perfluoro-o-phenylen-
emercury (o-C6F4Hg)3 (1), containing three Hg atoms in a
planar nine-membered ring [4], with different anionic species
in the rate of the nitration. It should be noted, however,
that by the end of the induction period all quantity of 1 dis-
solves completely in the benzene layer. Furthermore, when
the resulting nitroacenaphthenes are introduced in the
benzene phase before the reaction, the induction period
practically disappears and the rate of the process corre-
spondingly increases. These data could be explained by
an enhancement in the solubility of macrocycle 1 in the
organic phase due to its coordination with the Lewis basic
oxygen atoms of the nitro group, which prompted us to
investigate the complexation reactions of 1 with nitro
compounds.
In the present article, we report the synthesis and struc-
tures of the complexes of 1 with nitromethane, nitroben-
zene, 5-nitroacenaphthene and 1-nitropyrene. The
synthesized compounds are the first examples of host–guest
complexes of nitro derivatives with an anticrown.
(Clꢀ, Brꢀ, Iꢀ, SCNꢀ, closo-[B10H10]2ꢀ, closo-[B12H12]2ꢀ
,
[Fe(CN)6]3ꢀ, [Fe(CN)5(NO)]2ꢀ, etc.) [2a,2c,3k]. The ability
of 1 to coordinate neutral Lewis bases such as nitriles
[2a,2c], carbonyl compounds [2a,2c,2d,3c], arenes [2d,3n],
metallocenes [3i,3j], azulene [3a], 6-(N,N-dimethylamino)
pentafulvene [3a], polyynes [3b], dimethyl sulfide [3o] and
some others has also been established. In the majority of
structurally characterized complexes, the molecule of a
Lewis base is cooperatively bound by all Lewis acidic Hg
sites of the macrocycle, thereby leading to the unusual pyra-
midal, bipyramidal and sandwich structures or fragments.
2. Results and discussion
Complexes of 1 with nitromethane and nitrobenzene are
readily formed under conditions of recrystallization of 1
from the corresponding nitro compound as a solvent.
The isolated complexes are colourless crystalline solids sta-
ble to air. According to elemental analyses, the complexes
can be formulated as {[(o-C6F4Hg)3](CH3NO2)} (2) and
{[(o-C6F4Hg)3](C6H5NO2)} (3), respectively, i.e., contain
one molecule of a nitro compound per one macrocycle mol-
ecule. The complex of similar composition, {[(o-
C6F4Hg)3](C12H9NO2)} (4), was isolated as an orange-yel-
low fine-crystalline solid from the interaction of 1 with an
equimolar amount of 5-nitroacenaphthene in CH2Cl2.
The use of a fivefold excess of the nitro derivative in this
reaction leads to the same compound 4. The IR spectrum
of 2 in Nujol mull exhibits the mas(NO) band of the coordi-
nated nitro group at 1551 (m) cmꢀ1 shifted by 13 cmꢀ1 to a
low-frequency region in comparison with the mas(NO) band
for neat nitromethane. The IR spectrum of 3 in Nujol dis-
plays the mas(NO) band at 1507 (s) cmꢀ1 as well as the
ms(NO) band at 1345 (s) cmꢀ1 which are shifted by 17
and 3 cmꢀ1, respectively, to lower wave numbers relative
to the corresponding bands in the spectrum of uncoordi-
nated nitrobenzene. The IR spectrum of 4 contains the
mas(NO) bands at 1495 (m) and 1488 (m) cmꢀ1 and the
ms(NO) band at 1310 (ms) cmꢀ1, which are shifted by 14–
21 and 15 cmꢀ1, respectively, to lower frequencies relative
F
F
F
F
Hg
Hg
F
F
F
F
F
Hg
F
(1)
F
F
Another interesting feature of 1 is its capacity to transfer
organic and inorganic cations from an aqueous phase to an
organic phase which makes this macrocycle potentially use-
ful for phase transfer catalysis of electrophilic reactions
[2a,2c,3e]. Recently, we have reported a high activity of 1
in the phase transfer nitration of a number of aromatic
substrates (2-methylnaphthalene, 1,3- and 2,6-dimethyl-
naphthalenes, acenaphthene, anthracene, pyrene) with
dilute nitric acid in the presence of sodium nitrite as an ini-
tiator and sodium chloride as a promoter [3e]. A detailed
examination of the acenaphthene nitration catalysed by 1
revealed that the greatest reaction rates are observed on
the use of a 1:1 benzene–nitrobenzene mixture as the
organic phase. The replacement of the benzene–nitroben-
zene mixture by benzene, in which the major part of the
catalyst remains undissolved, leads to the appearance of
an induction period on the kinetic curve and to a decrease
to the corresponding bands (mas(NO) = 1509 cmꢀ1
,
ms(NO) = 1325 cmꢀ1) for free 5-nitroacenaphthene. The
199Hg NMR spectra of 2–4 at 20 ꢁC in THF (the initial
concentration is 8 · 10ꢀ2 M) show only negligible differ-
ences from the spectrum of free 1 but the addition of an
excess of a nitro compound (40:1) to a solution of the cor-
responding complex in THF leads to a noticeable down-
field shift of the 199Hg resonance (by 3–4 ppm in the case
of 2 and 3 and by 8 ppm in the case of 4).
Unlike the reactions with nitromethane, nitrobenzene
and 5-nitroacenaphthene, the reaction of 1 with 1-nitropy-

I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
955
Table 1
rene affords complexes of two different compositions, viz.
˚
Selected bond lengths (A) and angles (ꢁ) in complex 2
{[(o-C6F4Hg)3](C16H9NO2)} (5) and {[(o-C6F4Hg)3](C16H9
NO2)3} (6), containing one and three molecules of a nitro
compound, respectively, per one molecule of the macrocy-
cle. Complex 5 is formed in the interaction of 1 with an
equimolar amount of 1-nitropyrene in CH2Cl2 and repre-
sents a fine-crystalline yellow powder. Complex 6 is
obtained in the interaction of 1 with a threefold excess of
1-nitropyrene in a THF–CH3OH mixture and represents
a yellow-orange crystalline solid. An attempt to grow crys-
tals of 5 from THF resulted in the formation of complex 6.
The IR spectrum of 6 (Nujol) is characterized by the
mas(NO) and ms(NO) bands at 1501 (m) and 1305 (ms)
cmꢀ1 shifted by 9 and 25 cmꢀ1, respectively, to a low-
frequency region as compared to the corresponding bands
for free 1-nitropyrene (mas(NO) = 1510 (s) cmꢀ1, ms(NO)
= 1330 (vs) cmꢀ1). The IR spectrum of 5 shows the same
mas(NO) and ms(NO) bands as complex 6. The 199Hg
NMR spectrum of 6 in THF ([6]0 = 8 · 10ꢀ2 M), in con-
trast to the corresponding spectra of 2, 3 and 4, exhibits
a noticeable downfield shift of the 199Hg resonance (by
9 ppm) relative to that of starting 1 even in the absence
of an excess of a nitro compound.
Fig. 1 shows the structure of complex 2. Selected bond
lengths and angles for 2 are given in Table 1. The complex
occupies in the crystal a special position on a mirror plane
passing through the Hg(1), O(1), O(2), N(1) and C(10)
atoms and the mid-point of the Hg(2)ꢁ ꢁ ꢁHg (2A) line.
The nitromethane molecule in the complex behaves as a
bidentate Lewis base and forms two types of the Hg–O
bonds with the macrocycle. As seen from Fig. 1, one of
the oxygen atoms (O(1)) of the nitro group is cooperatively
coordinated here by all three Hg centres of 1 whereas the
other (O(2)) interacts with a single Hg centre. The Hg–O
Hg(1)–O(1)
Hg(2)–O(1)
Hg(2A)–O(1)a
Hg(1)–O(2)
N(1)–O(1)
3.078(8)
3.010(7)
3.010(7)
3.037(9)
1.243(12)
N(1)–O(2)
C(10)–N(1)
Hg(1)–C(1)
Hg(2)–C(2)
Hg(2)–C(7)
1.211(12)
1.477(13)
2.081(8)
2.061(8)
2.068(7)
C(1)–Hg(1)–C(1A)a
C(2)–Hg(2)–C(7)
O(1)–N(1)–O(2)
a
Symmetry transformation x, ꢀy + 3/2, z was used to generate equiv-
alent atoms.
172.7(4)
176.7(3)
122.7(9)
O(2)–N(1)–C(10)
O(1)–N(1)–C(10)
119.0(9)
118.3(9)
the limited accuracy of the X-ray experiment does not
allow judgement on the influence of the complexation of
nitromethane with 1 on the N–O bond lengths (the N–O
distances in free nitromethane are 1.221(5) and
˚
˚
1.215(5) A, av. 1.218 A [6]). The O(1)O(2)N(1)C(10) plane
of the nitromethane ligand is perpendicular to the mean
plane of the central nine-membered mercuracarbon ring
of 1.
In the crystal, molecules of the complex are associated
into infinite ladder-like chains (Fig. 2) due to shortened
intermolecular Hgꢁ ꢁ ꢁF and Hgꢁ ꢁ ꢁC contacts (Hgꢁ ꢁ ꢁF
˚
˚
3.197(5) and 3.264(5) A, Hgꢁ ꢁ ꢁC 3.536(7)–3.629(7) A)
˚
between the neighbouring molecules of 2 (rvdw(F) = 1.4 A
˚
[5c], rvdw(Carom) = 1.7 A [5c]). The chains are arranged
along the a crystal axis. The distance between the mean
planes of the central Hg3C6 rings of two adjacent macrocy-
cles in each chain is 3.33 A and the projections of their
centroids onto the plane parallel to these cycles are shifted
relative to each other by 5.88 A. The formation of similar
extended ladder-like chains with shortened intermolecular
Hgꢁ ꢁ ꢁF and Hgꢁ ꢁ ꢁC contacts was previously observed in
the crystal packing of the pyramidal 1:1 complex of 1 with
˚
˚
distances in
2
are close to each other (3.010(7)–
˚
˚
3.078(8) A) and are significantly shorter than the sum of
the van der Waals radii of Hg (1.73–2.00 A [5a,5b], 2.1 A
[5c]) and O (1.5 A [5c], 1.54 A [5d]) atoms. Unfortunately,
acrylonitrile (Hgꢁ ꢁ ꢁF 3.35 and 3.42 A, Hgꢁ ꢁ ꢁC 3.56 and
˚
˚
˚
3.67 A) [7] and the sandwich 2:2 complex of 1 with maleic
˚
˚
˚
˚
anhydride (Hgꢁ ꢁ ꢁF 3.32 A, Hgꢁ ꢁ ꢁC 3.42–3.63 A) [3c]. In the
latter case, the resulting chains are linked with one another
through additional shortened intermolecular Hgꢁ ꢁ ꢁF con-
˚
tacts (3.22–3.48 A).
The coordinated molecule of a nitro compound in 3, as
in 2, behaves as a bidentate Lewis base and forms two types
of the Hg–O bonds with 1 (Fig. 3). However, in the mode
of the coordination of a nitro group with the macrocycle,
complex 3 differs essentially from 2: while one oxygen atom
(O(2)) of a nitro derivative in 3 is bonded again to a single
Hg centre of 1, the other (O(1)) interacts only with two
rather than three Lewis acidic Hg sites. The Hg–O bond
˚
distances in 3 vary over wider limits (2.858(6)–3.254(5) A;
see Table 2) than in 2 and all these separations are again
substantially shorter than the corresponding van der Waals
distance. The length of the N(1)–O(1) bond in
3
˚
(1.235(7) A) differs only insignificantly from that of the
˚
N(1)–O(2) bond (1.211(9) A), both these distances being
close to the N–O distances in uncoordinated nitrobenzene
˚
˚
Fig. 1. Molecular structure of complex 2 in the crystal.
(1.223(5) and 1.229(5) A, av. 1.226 A [8]). An interesting

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I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
Fig. 2. View of a fragment of crystal packing of complex 2, showing the shortest intermolecular Hgꢁ ꢁ ꢁF and Hgꢁ ꢁ ꢁC contacts between neighbouring
molecules of 2.
structural feature of complex 3 is a strong deviation of the
oxygen atoms of the nitrobenzene ligand from its phenyl
ring plane (the dihedral angle between the planes of the
nitro group and the phenyl ring is 21.1ꢁ). In all other struc-
turally characterized nitrobenzene complexes with metal
compounds, this deviation is considerably smaller (0.5–
8.2ꢁ) [9]. As is known, free molecule of nitrobenzene has
an essentially planar structure (the corresponding inter-
plane angle is 2.1ꢁ [8]). The dihedral angles between the
mean plane of the central nine-membered mercuracarbon
cycle of 1 and the planes of the nitro and phenyl groups
are 69.3ꢁ and 65.3ꢁ, respectively.
In the crystal, complex 3 forms cofacial dimers due to
˚
shortened intermolecular Hgꢁ ꢁ ꢁHg (3.4675(7) A) and
˚
Hgꢁ ꢁ ꢁC (3.536(6)–3.617(6) A) contacts between the adja-
cent molecules of 3 (Fig. 4). The dimers are linked with
one another through additional shortened Hgꢁ ꢁ ꢁF contacts
˚
(3.280(5) and 3.412(5) A). In each of the dimers, the mutu-
ally parallel planes of the central Hg3C6 rings of the mac-
˚
rocycles are separated by 3.37 A and the projections of
Table 2
˚
Selected bond lengths (A) and angles (ꢁ) in complex 3
Hg(1)–O(1)
Hg(2)–O(1)
Hg(3)–O(2)
N(1)–O(1)
N(1)–O(2)
C(19)–N(1)
3.254(5)
2.953(5)
2.858(6)
1.235(7)
1.211(9)
1.453(8)
Hg(1)–C(1)
Hg(1)–C(14)
Hg(2)–C(2)
Hg(2)–C(7)
Hg(3)–C(8)
Hg(3)–C(13)
2.075(6)
2.062(6)
2.080(7)
2.076(6)
2.071(7)
2.078(7)
C(1)–Hg(1)–C(14)
C(2)–Hg(2)–C(7)
C(8)–Hg(3)–C(13)
176.9(3)
176.1(3)
175.3(3)
O(1)–N(1)–O(2)
O(2)–N(1)–C(19)
O(1)–N(1)–C(19)
121.2(7)
119.0(6)
119.8(6)
Fig. 3. Molecular structure of complex 3 in the crystal.

I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
957
bouring macrocycles in the dimers corresponds to an
eclipsed conformation. The formation of cofacial dimers
was also observed earlier in the crystal packing of the pyra-
midal 1:1 complex of 1 with n-butyronitrile (Hgꢁ ꢁ ꢁHg 3.372
˚
˚
and 3.512 A, Hgꢁ ꢁ ꢁC 3.58 and 3.59 A). These dimers are
linked in the crystal with each other through additional
˚
shortened Hgꢁ ꢁ ꢁF contacts (3.28 and 3.44 A) as well [10].
The pyramidal 1:1 complex of 1 with acetone is also asso-
ciated in the crystal into cofacial dimers due to shortened
˚
intermolecular Hgꢁ ꢁ ꢁHg (3.512 A) and Hgꢁ ꢁ ꢁC (3.402 and
˚
3.483 A) contacts [11]. However, in this case, no shortened
Hgꢁ ꢁ ꢁF contacts between the dimer units are observed.
In contrast to 2 and 3, analogous in its composition
complex 4 has a polydecker sandwich stucture in the crystal
(see Fig. 5). Interestingly, the aromatic rings of the nitroa-
rene units are disposed here virtually in parallel to the mac-
rocycles (the interplane angle is 2.4ꢁ), however, the plane of
the nitro group deviates from the aromatic ring plane of
the nitroacenaphthene ligand by 33.7ꢁ. As in 2 and 3, both
oxygen atoms of the NO2 group of the nitroarene in 4 are
involved in the bonding to the anticrown molecules. As
seen from Fig. 5, one of these oxygen atoms (O(1)) is simul-
taneously bound to all three Lewis acidic Hg sites of one of
˚
the adjacent macrocycles (Hg(1)–O(1) 3.069(5) A, Hg(2)–
˚
˚
O(1) 3.174(5) A, Hg(3)–O(1) 3.345(5) A, see Table 3)
whereas the other oxygen atom (O(2)) coordinates with a
single Hg centre of another molecule of 1 (Hg(3A)–O(2)
Fig. 4. View of the dimer of 3, showing the shortest intermolecular
Hgꢁ ꢁ ꢁHg and Hgꢁ ꢁ ꢁC contacts between neighbouring molecules of 3.
˚
the centroids of the Hg3C6 macrocyclic units onto the plane
parallel to these units are shifted with respect to one
3.075(5) A). The N–O distances in 4 are close to each other
(Table 3). The complex is characterized also by the pres-
ence of shortened Hg–C contacts between the mercury
˚
another by 3.00 A. The mutual orientation of the neigh-
Fig. 5. View of a fragment of a polydecker sandwich structure of complex 4 in the crystal. The shortest intramolecular Cꢁ ꢁ ꢁC contacts between the carbon
atoms of the nitroarene and the neighbouring macrocycles are omitted for clarity.

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I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
Table 3
is observed for the O(5) and O(6) atoms (the corresponding
dihedral angle is 34.3ꢁ). In the case of the O(1) and O(2)
atoms and the O(3) and O(4) atoms, these deviations are
19.9ꢁ and 23.9ꢁ, respectively. In contrast to 2–4, each mol-
ecule of the nitroarene in complex 6 is bonded to 1 by a sin-
gle oxygen atom which is coordinated only to one Hg
centre (Hg(2) or Hg(3)). The shortest Hg–O distances are
formed by the O(1) and O(3) atoms which interact with
the Hg(2) and Hg(3) centres, respectively (Hg(2)–O(1)
˚
Selected bond lengths (A) and angles (ꢁ) in complex 4
Hg(1)–O(1)
Hg(2)–O(1)
Hg(3)–O(1)
Hg(3A)–O(2)a
Hg(2)–C(19)
Hg(2)–C(20)
Hg(2A)–C(27)a
N(1)–O(1)
3.069(5)
3.174(5)
3.345(5)
3.075(5)
3.304(7)
3.193(7)
3.319(8)
1.220(7)
N(1)–O(2)
1.193(7)
1.546(10)
2.071(6)
2.075(6)
2.083(6)
2.082(6)
2.066(6)
2.071(6)
C(19)–N(1)
Hg(1)–C(1)
Hg(1)–C(14)
Hg(2)–C(2)
Hg(2)–C(7)
Hg(3)–C(8)
Hg(3)–C(13)
˚
˚
C(1)–Hg(1)–C(14)
C(7)–Hg(2)–C(2)
C(8)–Hg(3)–C(13)
a
172.9(2)
175.6(2)
177.6(2)
O(1)–N(1)–O(2)
O(1)–N(1)–C(19)
O(2)–N(1)–C(19)
125.7(6)
112.5(6)
121.8(6)
2.862(6) A, Hg(3)–O(3) 2.897(7) A). The oxygen atom
(O(6)) of the third nitropyrene ligand forms much longer
˚
Hg–O contact (Hg(3)–O(6) 3.568(11) A) which do, how-
Symmetry transformation 1 + x, y, z was used to generate equivalent
ever, remains slightly shorter than the corresponding van
der Waals distance. An additional contribution to the
bonding of this nitropyrene ligand to the macrocycle is
made, apparently, by shortened Hg–C contacts between
the Hg(1) and Hg(3) centres of 1 and the carbon atoms
atoms.
centres of 1 and the carbon atoms of the nitroarene mole-
cules (Hg(2)–C(20) 3.193(7) A, Hg(2)–C(19) 3.304(7) A,
Hg(2A)–C(27) 3.319(8) A) as well as shortened C–C con-
tacts (3.280(9)–3.539(10) A) between the carbon atoms of
the nitroarene and the macrocycle. The mutual orientation
of the macrocycles in 4 is close to an eclipsed conforma-
tion. The projections of the centroids of the neighbouring
macrocycles onto the plane parallel to these cycles are
shifted with respect to one another by 5.44 A, thus leading
to the ladder-like structure of 4.
The structure of complex 6 is shown in Fig. 6. Selected
bond lengths and angles for 6 are listed in Table 4. Unlike
2–5, complex 6 contains three coordinated molecules of a
nitro compound, two of which are located on one side of
the metallacycle plane while the third nitroarene molecule
is disposed on its other side. The pyrene rings of all three
1-nitropyrene ligands in 6 are practically parallel to the
mean plane of the central nine-membered cycle of 1 (the
corresponding interplane angles are in the range of 3–4ꢁ)
but the oxygen atoms of the nitro groups are again devi-
ated from the aromatic ring planes. The greatest deviation
˚
˚
˚
˚
of the aromatic pyrene ring (Hg(1)–C(57) 3.264(8) A,
˚
˚
˚
Hg(1)–C(54) 3.382(9) A, Hg(3)–C(51) 3.372(9) A, Hg(3)–
˚
C(56) 3.507(9) A) as well as by shortened C–C contacts
(3.301(10)–3.520(11) A) between the aromatic pyrene ring
˚
and the adjacent C6F4 fragment of the macrocycle. The
ability of 1 to give complexes with aromatic hydrocarbons
(including unsubstituted pyrene) has previously been estab-
lished by Gabba¨ı et al. [12]. These 1:1 complexes have poly-
decker sandwich structures in the solid state. In the case of
the pyrene complex, the shortest Hg–C distances between
the pyrene carbon atoms and the Hg sites of 1 range from
˚
˚
3.353(16) to 3.553(17) A [12].
In the crystal, molecules of 6 are associated to form a com-
plex three-dimensional structure. In this crystal structure,
one may distinguish extended stacks wherein each two near-
est macrocycle moieties are separated by three nitropyrene
units belonging to three different molecules of the adduct.
The bonding of the nitropyrene fragments in the stack to
one another is accomplished due to aromatic stacking inter-
Fig. 6. Molecular structure of complex 6 in the crystal. The shortest intramolecular Cꢁ ꢁ ꢁC contacts between the carbon atoms of the nitroarene and the
neighbouring macrocycles are omitted for clarity.

I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
959
Table 4
Selected bond lengths (A) and angles (ꢁ) in complex 6
the nitrobenzene ligand in 1:1 complex 3 is bound by one of
its oxygen atoms to only two Hg centres whereas the other
oxygen atom coordinates again with a single Hg site. Quite
different structure is realized in the case of the nitro-
acenaphthene 1:1 complex 4 representing a polydecker sand-
wich in the crystal. In this adduct too, the NO2 functionality
of each nitroarene moiety acts as a bidentate Lewis base
forming three Hg–O bonds with one of the adjacent macro-
cycles and a single Hg–O bond with the other. Finally, in the
1:3 complex of 1 with 1-nitropyrene, the NO2 group in all
three nitroarene ligands behaves as a monodentate Lewis
base and is coordinated only to one Lewis acidic Hg site of
1. Note, in the previously described 1:3 complexes of 1 with
DMSO [13], ethyl acetate [2a,2c,13] and acetone [2d], two of
three Lewisbasic species are cooperativelycoordinated by all
mercury centres of 1, forming the corresponding bipyrami-
dal fragment. A characteristic structural feature of com-
plexes 4 and 6 is also the mutually parallel arrangement of
1 and the aromatic rings of the nitroarene units as well as
the presence of shortened Hg–C contacts between the Hg
sites of 1 and the carbon atoms of the nitro derivative. In
addition, in the structures of 4 and 6 shortened C–C contacts
between the carbon atoms of the coordinated nitroarene and
1 are observed.
˚
Hg(2)–O(1)
Hg(3)–O(3)
Hg(3)–O(6)
Hg(1)–C(57)
Hg(1)–C(54)
Hg(3)–C(51)
Hg(3)–C(56)
N(1)–O(1)
2.862(6)
2.897(7)
3.568(11)
3.264(8)
3.382(9)
3.372(9)
3.507(9)
1.239(8)
1.223(8)
1.461(9)
1.289(10)
N(2)–O(4)
C(35)–N(2)
N(3)–O(5)
N(3)–O(6)
C(51)–N(3)
Hg(1)–C(1)
Hg(1)–C(14)
Hg(2)–C(2)
Hg(2)–C(7)
Hg(3)–C(8)
Hg(3)–C(13)
1.208(10)
1.435(11)
1.255(13)
1.301(13)
1.351(13)
2.054(7)
2.059(7)
2.072(7)
2.064(7)
2.064(7)
2.049(6)
N(1)–O(2)
C(19)–N(1)
N(2)–O(3)
C(1)–Hg(1)–C(14)
C(2)–Hg(2)–C(7)
C(8)–Hg(3)–C(13)
O(1)–N(1)–O(2)
O(2)–N(1)–C(19)
O(1)–N(1)–C(19)
175.8(3)
O(3)–N(2)–O(4)
O(4)–N(2)–C(35)
O(3)–N(2)–C(35)
O(5)–N(3)–O(6)
O(5)–N(3)–C(51)
O(6)–N(3)–C(51)
120.1(8)
176.1(3)
175.3(3)
122.7(7)
120.4(7)
116.8(6)
124.2(8)
115.7(8)
118.3(12)
119.2(11)
122.2(11)
actions (the shortest intermolecular Cꢁ ꢁ ꢁC distances are in
˚
the range of 3.367(10)–3.479(11) A, the distances between
˚
the planes of the adjacent pyrene rings are 3.44 and 3.55 A)
whereas the macrocycle and pyrene units are linked with
˚
each other due to shortened Hgꢁ ꢁ ꢁC (3.297(7)–3.431(7) A)
˚
and Cꢁ ꢁ ꢁC (3.382(11)–3.536(11) A) contacts.
The geometry of the macrocycle does not change essen-
tially upon its complexation with the above nitro com-
pounds. The C–Hg–C bond angles in 2–4 and 6, as in
free 1, are close to 180ꢁ. The Hg–C bond lengths are unex-
4. Experimental
The starting macrocycle 1 was synthesized by the
method described in [4a]. Commercial nitromethane and
nitrobenzene were distilled prior to use, 1-nitropyrene
was purified by sublimation in vacuum with subsequent
recrystallization from EtOH–PhH mixture, commercial 5-
nitroacenaphthene was used without additional purifica-
tion. The IR spectra were recorded as Nujol mulls on a
Nicolet Magna-IR 750 Series II Fourier spectrometer.
The 199Hg NMR spectra were recorded on a Bruker WP-
200 SY instrument using Ph2Hg in pyridine as an external
standard.
˚
ceptional and span the range of 2.049(6)–2.083(6) A.
Returning now to the kinetics of the phase transfer ace-
naphthene nitration with dilute nitric acid in the presence
of sodium nitrite as an initiator, sodium chloride as a pro-
moter and macrocycle 1 as a catalyst [3e] (see Section 1), we
note that the synthesized 4 is indeed better soluble in ben-
zene than the starting 1, particularly when an excess of 5-
nitroacenaphthene is present in C6H6. Still further increase
in the solubility of 4 and 1 in benzene is achieved on the
combined use of 5-nitroacenaphthene and an aqueous solu-
tion of sodium chloride (see Section 4). These data suggest
that the above-mentioned disappearance of the induction
period in the phase transfer acenaphthene nitration (which
was observed on the addition of nitroacenaphthenes to the
benzene phase before the reaction [3e]) is due apparently to
an enhancement in the solubility of both macrocycle 1 and
its chloride complex in C6H6.
4.1. Synthesis of complex 2
Compound 1 (0.1047 g, 0.1 mmol) was dissolved in 5 ml
of boiling nitromethane and the resulting solution was
cooled to room temperature; shortly, colourless crystals of
complex 2 began to precipitate from the solution. Then,
the reaction mixture was allowed to slowly evaporate to
0.5 ml at 20 ꢁC. After 1 day, the precipitated fine colourless
crystals of 2 were filtered off, washed with Et2O (2 · 1 ml)
and dried for 3 h at 20 ꢁC in vacuum. The yield of 2 was
0.0809 g (73%). Anal. Calc. for C19H3F12Hg3NO2: C,
20.62; H, 0.27; F, 20.59. Found: C, 20.38; H, 0.23; F, 19.83%.
3. Conclusion
Macrocycle 1 readily binds various nitro compounds such
as nitromethane, nitrobenzene, 5-nitroacenaphthene and 1-
nitropyrene to afford complexes whose structures are
strongly dependent on the nature of the starting nitro deriv-
ative. In 1:1 complex 2, the nitromethane ligand behaves as a
bidentate Lewis base, one oxygen atom of which interacts
with three mercury centres (forming a pyramidal fragment)
whereas the other is bonded to a single Hg atom. By contrast,
4.2. Synthesis of complex 3
Compound 1 (0.1045 g, 0.1 mmol) was dissolved under
heating (100–120 ꢁC) in 1 ml of nitrobenzene and the
resulting solution, after evaporation to 0.5 ml, was allowed

960
I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
to stand at room temperature in a closed system. After 1
day, the precipitated colourless crystals of complex 3 were
filtered off, washed with CH2Cl2 (2 · 0.5 ml) and dried for
3 h at 20 ꢁC in vacuum. The yield of 3 was 0.0568 g (49%).
Anal. Calc. for C24H5F12NO2Hg3 (%): C, 24.64; H, 0.43; F,
19.50. Found: C, 24.54; H, 0.34; F, 19.73%.
(2 · 0.5 ml) and dried for 3 h at 20 ꢁC in vacuum. The yield
of 5 was 0.1059 g (82%). Anal. Calc. for C34H9F12Hg3NO2:
C, 31.58; H, 0.70; F, 17.63. Found: C, 31.45; H, 0.64; F,
17.66%.
4.5. Synthesis of complex 6
4.3. Synthesis of complex 4
To a solution of 1-nitropyrene (0.0738 g, 0.3 mmol) in
THF (3 ml) was added at room temperature a solution of
1 (0.1047 g, 0.1 mmol) in methanol (3 ml) and the reaction
mixture was allowed to slowly evaporate to 0.5 ml at 20 ꢁC.
After 2 days, the precipitated yellow-orange crystals of
complex 6 were filtered off, washed with Et2O (3 · 1 ml)
and dried for 4 h at 20 ꢁC in vacuum. The yield of 6 was
0.1629 g (91%). Anal. Calc. for C66H27F12Hg3N3O6: C,
44.32; H, 1.51; F, 12.76. Found: C, 44.07; H, 1.67; F,
12.91%.
To a solution of 1 (0.1043 g, 0.1 mmol) in CH2Cl2
(15 ml) was added at room temperature a solution 5-nitro-
acenaphthene (0.0203 g, 0.1 mmol) in CH2Cl2 (3 ml) and
the resulting mixture was allowed to slowly evaporate for
2 days to 0.5 ml at 20 ꢁC. Then, the precipitated orange-
yellow fine-crystalline complex 4 was filtered off, washed
with ether (2 · 1 ml) and dried for 3 h at 20 ꢁC in vacuum.
The yield of 4 was 0.0817 g (66%). Anal. Calc. for
C30H9F12Hg3NO2 (%): C, 28.94; H, 0.73; F, 18.31. Found:
C, 28.92; H, 0.90; F, 17.95%.
4.6. Experiments on the solubilization of 4 and 1 in benzene
4.4. Synthesis of complex 5
An amount of 25 mg of complex 4 was stirred with 9 ml
of a benzene solution of 5-nitroacenaphthene (0.25 g) at
room temperature. In the course of stirring, approximately
half the taken quantity of 4 dissolved in C6H6. Then, the
resulting mixture was stirred with 4.5 ml of an aqueous
solution of sodium chloride ([Clꢀ] = 0.50 M), which led
to a complete dissolution of the rest of the undissolved 4.
In the other experiment, a suspension of 21 mg of 1 in
9 ml of benzene, containing 0.25 g of 5-nitroacenaphthene,
To a solution of 1 (0.1049 g, 0.1 mmol) in CH2Cl2
(15 ml) was added at room temperature a solution of 1-
nitropyrene (0.0246 g, 0.1 mmol) in CH2Cl2 (3 ml). Within
5 min, yellow flakes of complex 5 began to precipitate. The
subsequent slow evaporation of the reaction mixture to
2 ml at 20 ꢁC for 5 days gave the fine-crystalline yellow
powder of 5 which was filtered off, washed with CH2Cl2
Table 5
Crystal data, data collection and structure refinement parameters for 2, 3, 4 and 6
Compound
2
3
4
6
Formula
C
19H3F12Hg3NO2
C24H5F12Hg3NO2
1169.06
Colourless, prism
0.25 · 0.20 · 0.10
200(2)
Monoclinic
C2/c
20.390(3)
17.289(3)
15.948(3)
90
119.454(3)
90
4895(2)
8
3.172
60
C30H9F12Hg3NO2
1245.15
Orange, prism
0.22 · 0.08 · 0.08
120(2)
Monoclinic
P21/n
8.2949(5)
20.168(1)
17.099(1)
90
100.088(1)
90
2816.3(3)
4
2.937
58
C66H27F12Hg3N3O6
1787.68
Yellow, prism
0.22 · 0.15 · 0.10
120(2)
Molecular weight
Crystal colour, habit
Crystal size (mm3)
Temperature (K)
Crystal system
Space group
1106.99
Colourless, plate
0.25 · 0.20 · 0.05
120(2)
Monoclinic
P21/m
6.7579(7)
16.017(2)
9.751(1)
90
99.235(2)
90
1041.7(2)
2
3.529
58
221.79
Triclinic
ꢀ
P1
˚
a (A)
9.2798(5)
15.2823(8)
20.013(1)
68.255(1)
86.166(1)
78.488(1)
2583.1(2)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
qcalc (g cmꢀ3
2hmax (ꢁ)
)
2.298
60
90.01
l (Mo Ka) (cmꢀ1
)
188.89
164.26
Minimum/maximum transmission factors
Number of collected reflections
0.072/0.481
10060
0.033/0.099
29052
0.107/0.357
30999
0.169/0.358
30698
Number of unique reflections (Rint
)
2795 (0.0411)
2447
175
0.0416
0.1008
7126 (0.0477)
5066
379
0.0374
0.0936
7480 (0.0522)
5502
433
0.0290
0.0592
14843 (0.0438)
10428
811
0.0461
0.1107
Number of observed reflections (I > 2r(I))
Number of parameters
R1 (on F for observed reflections)a
wR2 (on F2 for all reflections)b
P
P
a
R1 = iFoj ꢀ jFci/ jFoj.
P
P
2
2
1=2
b
wR2 ¼ f ½wðF 2o ꢀ F c2Þ ꢂ= ½wðF 2oÞ ꢂg
.

I.A. Tikhonova et al. / Journal of Organometallic Chemistry 692 (2007) 953–962
961
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111;
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was stirred with 4.5 ml of a 0.50 M aqueous solution of
NaCl at 20 ꢁC. As a result, all the quantity of 1 dissolved
in the organic layer. Under the same conditions but in
the absence of 5-nitroacenaphthene, the major part of 1
remained undissolved in benzene.
(e) J.D. Wuest, Acc. Chem. Res. 32 (1999) 81;
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4.7. X-ray diffraction study
[3] (a) I.A. Tikhonova, K.I. Tugashov, F.M. Dolgushin, A.A. Yak-
ovenko, B.N. Strunin, P.V. Petrovskii, G.G. Furin, V.B. Shur, Inorg.
Chim. Acta 359 (2006) 2728;
Crystals of complex 2 for the X-ray diffraction study were
obtained as described above but were not dried in vacuum.
Crystals of complexes 3, 4 and 6 were grown by slow evapo-
ration of their solutions in CH2Cl2 (3 and 4) or in a EtOH–
THF (2:3) mixture (6) and were not dried in vacuum as well.
Details of crystal data, data collection and structure refine-
ment parameters for 2–4 and 6 are given in Table 5. Single-
crystal X-ray diffraction experiments were carried out with
a Bruker SMART 1000 CCD diffractometer (graphite
(b) T.J. Taylor, F.P. Gabba¨ı, Organometallics 25 (2006) 2143;
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˚
monochromated Mo Ka radiation, k = 0.71073 A, x-
scans). Semi-empirical method SADABS [14] was applied for
absorption correction. The structures were solved by direct
methods and refined by the full-matrix least-squares tech-
nique against F2 with the anisotropic displacement parame-
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placed geometrically and included in the structure factors
calculation in the riding motion approximation. Data reduc-
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Acknowledgements
This work was supported by the Russian Foundation
for Basic Research (the Project code 05-03-32891), the Rus-
sian Science Support Foundation (K.I.T.) and the Program
for the State Support of Leading Scientific Schools of the
Russian Federation (the Project code 1153.2006.3).
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Appendix A. Supplementary material
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Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic Data
Centre. CCDC 610041, 610042, 610043 and 610044 contain
the supplementary crystallographic data for 2, 3, 4 and 6.
These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-
mail: deposit@ccdc.cam.ac.uk. Supplementary data associ-
ated with this article can be found, in the online version, at
doi:10.1016/j.jorganchem.2006.10.048.
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