Coordination chemistry of mercury-containing anticrowns. Complexation of nitrate and sulfate anions with the three-mercury anticrown (o-C 6F4Hg)3 and the influence of the nature of a countercation on the structure of the resulting nitrate complexes

Article abstract of DOI:10.1016/j.jorganchem.2013.04.059

The interaction of the three-mercury anticrown (o-C₆F ₄Hg)₃ (1) with [PPN]NO₃ and [PPh ₄]NO₃ in an ethanol solution yields nitrate complexes, [PPN]{[(o-C₆F₄Hg)₃]₂(NO ₃)} (2) and [PPh₄]{[(o-C₆F₄Hg) ₃]₂(NO₃)} (3), respectively, having double-decker sandwich structures. In both adducts, the nitrate anion behaves as a tridentate ligand and is coordinated through the oxygen atoms with the Hg sites of each anticrown unit in an η³:η¹ fashion. However, whereas complex 3 constitutes a bent sandwich in the crystal, the planes of the anticrown molecules in complex 2 are parallel to each other. The reaction of 1 with [PhNMe₃]₂SO₄ results in the formation of a sulfate complex, [PhNMe₃]₂{[(o-C ₆F₄Hg)₃]₂(SO₄)} (4), the subsequent recrystallization of which from the acetone/ethanol mixture yields a solvate, 4·Me₂CO·3EtOH, representing also a double-decker sandwich according to X-ray crystallography. The sulfate anion in this sandwich is a tetradentate ligand and is bound to each anticrown species by two oxygen atoms in an η³:η¹ fashion as well. Like 3, complex 4·Me₂CO·3EtOH has a bent sandwich geometry. The complex is characterized also by the presence of H-bonds between two oxygen atoms of the coordinated sulfate anion and two ethanol molecules. The synthesized sandwich compounds 2, 3 and 4·Me₂CO·3EtOH are the novel structural type of complexes of an anticrown with nitrate and sulfate anions as well as the first examples of structurally characterized complexes of 1 with oxygen-containing anions.

Full text of DOI:10.1016/j.jorganchem.2013.04.059

Journal of Organometallic Chemistry 747 (2013) 167e173
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Coordination chemistry of mercury-containing anticrowns.
Complexation of nitrate and sulfate anions with the three-mercury
anticrown (o-C6F4Hg)3 and the influence of the nature of a
countercation on the structure of the resulting nitrate complexes
K.I. Tugashov, D.A. Gribanyov, F.M. Dolgushin, A.F. Smol’yakov, A.S. Peregudov,
*
M.Kh. Minacheva, B.N. Strunin, I.A. Tikhonova, V.B. Shur
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
a r t i c l e i n f o
a b s t r a c t
Article history:
The interaction of the three-mercury anticrown (o-C6F4Hg)3 (1) with [PPN]NO3 and [PPh4]NO3 in an
ethanol solution yields nitrate complexes, [PPN]{[(o-C6F4Hg)3]2(NO3)} (2) and [PPh4]{[(o-
C6F4Hg)3]2(NO3)} (3), respectively, having double-decker sandwich structures. In both adducts, the ni-
trate anion behaves as a tridentate ligand and is coordinated through the oxygen atoms with the Hg sites
Received 1 March 2013
Received in revised form
29 April 2013
Accepted 30 April 2013
of each anticrown unit in an h3 h1 fashion. However, whereas complex 3 constitutes a bent sandwich in
:
the crystal, the planes of the anticrown molecules in complex 2 are parallel to each other. The reaction of
1 with [PhNMe3]2SO4 results in the formation of a sulfate complex, [PhNMe3]2{[(o-C6F4Hg)3]2(SO4)} (4),
Dedicated to Professor Vladimir Bregadze
on the occasion of his 75th birthday.
the subsequent recrystallization of which from the acetone/ethanol mixture yields
a solvate,
4$Me2CO$3EtOH, representing also a double-decker sandwich according to X-ray crystallography. The
Keywords:
Anticrowns
Anions
Complexes
Polymercuramacrocycles
Sandwiches
sulfate anion in this sandwich is a tetradentate ligand and is bound to each anticrown species by two
oxygen atoms in an h3 h1 fashion as well. Like 3, complex 4$Me2CO$3EtOH has a bent sandwich ge-
:
ometry. The complex is characterized also by the presence of H-bonds between two oxygen atoms of the
coordinated sulfate anion and two ethanol molecules. The synthesized sandwich compounds 2, 3 and
4$Me2CO$3EtOH are the novel structural type of complexes of an anticrown with nitrate and sulfate
anions as well as the first examples of structurally characterized complexes of 1 with oxygen-containing
anions.
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
Golloch [23a] but its ability to function as an anticrown was
demonstrated for the first time in 1991 in our laboratory [24,25].
One of the promising approaches to the development of highly
efficient and selective anion receptors is based on the use of
macrocyclic multidentate Lewis acids or anticrowns [1] for this
purpose. Over last two decades, the coordination and catalytic
chemistry of these novel reagents representing charge-reversed
analogs of crown ethers and related species has attracted consid-
erable attention (see reviews [2e8] and recent papers cited in Refs.
[9e22]). Among presently known anticrowns, the most studied is
cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 (1)
containing three Hg atoms in a planar nine-membered ring [23].
This remarkable compound was synthesized in 1968 by Sartory and
F
F
F
F
F
F
Hg
F
F
Hg
(1)
Hg
F
F
F
* Corresponding author.
E-mail address: vbshur@ineos.ac.ru (V.B. Shur).
F
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.04.059

168
K.I. Tugashov et al. / Journal of Organometallic Chemistry 747 (2013) 167e173
Macrocycle 1 exhibits an extremely high affinity toward various
anions and neutral Lewis bases [2,4e6,9e22] which is due to a
strong electron-withdrawing effect of the fluorine substituents as
well as ready steric accessibility of the Hg atoms. Particularly
important is the capacity of 1 to bind Lewis basic species cooper-
atively by all Lewis acidic centres of the cycle which increases
sharply the stability of the resulting complexes.
To date, complexes of1 withbromide [24], iodide[25], thiocyanate
[26], closo-[B10H10] ]
2ꢀ [27], closo-[B12H12 2ꢀ [27], closo-[B12H11SCN]2ꢀ
[28], [Fe(CN)6]3ꢀ [29], [Fe(CN)5(NO)]2ꢀ [29] and [H3BCN]ꢀ [13] anions
were prepared and structurally characterized. There are also spec-
troscopic data on the complexation of 1 in THF with borohydride, [p-
O2NC6H4S]ꢀ and [p-O2NC6H4O]ꢀ anions [4,30]. According to X-ray
crystallography, the 1:1 complexes of 1 with bromide, iodide and
thiocyanate anions form in the crystal infinite chains representing
bent polydecker sandwiches [24e26]. The interaction of the above-
mentioned polyhedral anionic boranes as well as [Fe(CN)6]3ꢀ with a
twofold excess of 1 yields the corresponding bent double-decker
sandwiches {[(o-C6F4Hg)3]2(B10H10)}2ꢀ, {[(o-C6F4Hg)3]2(B12H12)}2ꢀ
,
{[(o-C6F4Hg)3]2(B12H11SCN)}2ꢀ and {[(o-C6F4Hg)3]2[Fe(CN)6]}3ꢀ [27e
29]. At the same time, the double-decker sandwich complexes {[(o-
C6F4Hg)3]2[Fe(CN)5(NO)]}2ꢀ [29] and {[(o-C6F4Hg)3]2(H3BCN)}ꢀ [13],
isolated from the reactions of 1 with [Fe(CN)5(NO)]2ꢀ and [H3BCN]ꢀ,
are characterized by a parallel arrangement of the anticrown rings. In
all of the above double-decker sandwiches, the BH or/and CN groups
of the anionic guest are involved in the coordination with the Hg
atoms of the anticrown moieties and in the case of {[(o-
C6F4Hg)3]2(B12H11SCN)}2ꢀ the sulfur atom of the SCN substituent
takes part in the bonding along with the BH groups.
Fig. 1. Molecular structure of complex 2 in the crystal. Only one of two positions of the
disordered nitrate anion is depicted; the hydrogen atoms of the PPN cation are omitted
for clarity.
The coordinated nitrate ion in 2 retains its planar trigonal ge-
ometry and the lengths of the NeO bonds (1.22(2), 1.25(4) and
ꢀ
1.25(3) A) are changed only slightly, if any, as a result of the
complexation with 1 (the NeO distances in free NOꢀ3 ion are 1.239 A
ꢀ
[32]). The plane of the nitrate anion in 2 is practically perpendicular
to the mean planes of the central nine-membered rings of the
macrocycles (the corresponding interplane angle is 88ꢂ). The
mutual orientation of the mercury macrocycles in the complex
corresponds to a staggered conformation and the projections of
their centroids onto the plane parallel to these cycles are shifted
In the present article, data on the complexation of 1 with nitrate
and sulfate anions are reported. The results of this study demon-
strate for the first time the influence of the nature of a counter-
cation upon the structure of complexes of an anticrown with
anionic species.
relative to each other only by 0.35 A. The [PPN]þ countercation in 2
ꢀ
as in the majority of other salts of this cationic species [33] has a
bent geometry (the P(1)eN(2)eP(2) bond angle is 157.2(4)ꢂ).
In the crystal structure of complex 2, the {[(o-C6F4Hg)3]2(NO3)}ꢀ
anions form layers which are parallel to ab crystal plane. The for-
mation of these layers is due mainly to stacking interactions be-
tween the perfluorinated o-phenylene rings (the corresponding
2. Results and discussion
The interaction of macrocycle 1 with [PPN]NO3$H2O (where PPN
is (Ph3P)2Nþ) in an ethanol solution at room temperature
(1:NOꢀ3 ¼ 2:1) leads to precipitation of a colorless, fine crystalline
solid which was identified as
a
nitrate complex [PPN]{[(o-
ꢀ
intermolecular C/C distances are 3.291(5)e3.326(6) A) as well as
C6F4Hg)3]2(NO3)} (2), containing two anticrown species per one
nitrate anion, on the basis of elemental analysis. The complex was
obtained in 61% yield. The room-temperature 199Hg NMR spectrum
of 2 in THF ([2]0 ¼ 4 ꢁ 10ꢀ2 M) exhibits a downfield 199Hg shift of
12.0 ppm relative to that of neat 1, thus suggesting the presence of
anticrown molecules coordinated with nitrate anions in the
solution.
shortened (as compared to the sum of the van der Waals radii)
ꢀ
intermolecular Hg/Hg (3.8446(3) A) and Hg/C (3.437(4)e
ꢀ
3.655(4) A) contacts between the neighboring anionic units. The
anionic layers in the crystal of 2 alternate with the corresponding
cationic [PPN]þ layers which are parallel to the same crystal plane.
The crystal structure of complex 2 contains also shortened CeF/H
ꢀ
contacts (2.46e2.50 A) between the anticrown moieties and the
[PPN]þ countercations.
In the crystal, complex 2 occupies a special position on the
inversion centre which results in disordering the nitrate anion over
two positions. As seen from Fig. 1, the complex has a double-decker
sandwich structure. The nitrate anion in 2 is disposed between the
mutually parallel planes of two anticrown units and behaves as a
tridentate ligand, forming two types of coordination bonds with
the molecules of 1. One type is the cooperative bonding of the
oxygen atoms O(1) and O(2) of the nitrate anion by all three Hg sites
of the neighboring molecule of the anticrown. The HgeO distances
in these h3 coordination fragments of the complex range from
The nitrate complex of analogous composition, [PPh4]{[(o-
C6F4Hg)3]2(NO3)} (3), was isolated as colorless crystals in 66%
yield from the interaction of 1 with [PPh4]NO3 in ethanol at
Table 1
ꢂ
ꢀ
Selected bond lengths (A) and angles ( ) in complex 2.
Hg(1)eO(1)
Hg(2)eO(1)
Hg(3)eO(1)
2.676(6)
2.871(7)
3.260(9)
3.163(8)
2.833(6)
2.708(6)
120.7(13)
120(3)
Hg(3)eO(3)
Hg(1A)eO(3)a
N(1)eO(1)
N(1)eO(2)
N(1)eO(3)
3.543(8)
3.137(8)
1.25(3)
1.25(4)
1.22(2)
ꢀ
ꢀ
2.676(6) to 3.260(9) A (av. 2.92 A; see Table 1) and they are all
ꢀ
within the sum of the van der Waals radii of mercury (1.73e2.00 A
[31a,b], 2.1 A [31c]) and oxygen (1.54 A [31d]) atoms. Another type
Hg(1A)eO(2)a
Hg(2A)eO(2)a
Hg(3A)eO(2)a
O(1)eN(1)eO(2)
O(1)eN(1)eO(3)
ꢀ
ꢀ
of the bonding is realized with the participation of the oxygen atom
ꢀ
O(2)eN(1)eO(3)
119(2)
O(3) which forms a relatively short HgeO contact (3.137(8) A) with
one of the molecules of the anticrown and a considerably longer
a
ꢀ
HgeO contact (3.543(8) A) with the other molecule of 1.
Symmetry transformation ex, ey, ezþ1 was used to generate equivalent atoms.

K.I. Tugashov et al. / Journal of Organometallic Chemistry 747 (2013) 167e173
169
Fig. 2. Molecular structure of complex 3 in the crystal. The hydrogen atoms of the
tetraphenylphosphonium cation are omitted for clarity.
Fig. 3. Molecular structure of complex 4$Me2CO$3EtOH in the crystal. The hydrogen
atoms of the phenyltrimethylammonium cations as well as of the alkyl groups of the
acetone and ethanol molecules are omitted for clarity.
room temperature (1:NOꢀ3 ¼ 2:1). However, it turned out unex-
pectedly that this complex differs in its structure from 2 and has a
bent double-decker sandwich geometry.
The structure of 3 is depicted in Fig. 2. Selected bond lengths and
angles for 3 are listed in Table 2. As in 2, the nitrate anion in
complex 3 is located between the planes of two anticrown species
but these planes in 3, in contrast to those in 2, are not parallel to one
another (the dihedral angle between the mean planes of the central
9-membered rings of the macrocycles is 34.2ꢂ). Interestingly,
despite this difference, the nitrate anion in complex 3 behaves
again as a tridentate ligand and, as in 2, is bonded to each anticrown
Sulfate complexes of macrocycle 1 were obtained in 74e78%
yield by the interaction of 1 with [PhNMe3]2SO4$3H2O and
[PPh3Me]2SO4$2H2O at room temperature in CH2Cl2 (1:SO24ꢀ ¼ 2:1).
The complexes have composition [PhNMe3]2{[(o-C6F4Hg)3]2(SO4)}
(4) and [PPh3NMe]2{[(o-C6F4Hg)3]2(SO4)} (5) respectively, i.e.
contain, as in the case of 2 and 3, two anticrown hosts per one
anionic guest. The room-temperature 199Hg NMR spectrum of 5 in
[D6]acetone ([5]o ¼ 4 ꢁ 10ꢀ2 M) shows a downfield 199Hg shift of
52.0 ppm relative to that of neat 1, thus indicating on the presence
of the molecules of 1 coordinated with sulfate anions in the solu-
tion. Attempts to obtain a satisfactory 199Hg NMR spectrum of
complex 4 failed because of insufficiently good solubility of 4 in
organic solvents.
unit in an h3
:h
1 fashion. The HgeO distances in the
h
3 coordination
ꢀ
ꢀ
fragments of 3 span the range 2.688(3)e3.276(3) A (av. 2.93 A) and
are comparable with the corresponding distances in 2. An addi-
tional contribution to the bonding is made by the oxygen atom O(3)
which coordinates to a single Hg atom of each anticrown molecule.
The HgeO distances in these h1 coordination fragments of the
Recrystallization of complex
4 from the acetone/ethanol
mixture (1:1) gave crystals suitable for the X-ray diffraction study.
The crystals were not dried and contained one molecule of acetone
and three ethanol molecules per one molecule of 4 according to X-
ray crystallography. Unfortunately, good single crystals of complex
5 could not be grown despite numerous attempts.
ꢀ
ꢀ
complex (Hg(3)eO(3) 2.885(3) A, Hg(6)eO(3) 2.723(3) A) are
considerably shorter than those in 2.
The geometry of the nitrate anion in complex 3, as in 2, is close
to that of uncoordinated NOꢀ3 ion. The room-temperature 199Hg
NMR spectrum of 3 in THF ([3]o ¼ 4 ꢁ 10ꢀ2 M) is characterized by a
downfield 199Hg shift of 12.2 ppm relative to that of free 1. The
closeness of the 199Hg shifts for 2 (see above) and 3 may indicate on
the identical structure of these complexes in the solution.
Previously, Hawthorne and co-workers described two bis-nitrate
complexes of o-carboranyl-mercury anticrown (o-C2B10H10Hg)4
which contains four Hg atoms in a 12-membered cycle [34]. In one of
these complexes, {[(o-C2B10H10Hg)4](NO3)2}2ꢀ, both nitrates are
bonded to the anticrown molecule in an unusual tridentate, face-on
fashion, whereas in the other complex, {[(o-C2B10H10Hg)4]
(NO3)2(H2O)}2ꢀ, the nitrate species behave as monodentate ligands
and coordinate with the macrocycle in an h4 and h2 fashion
respectively.
Fig. 3 shows the structure of 4$Me2CO$3EtOH. Like 3, complex
4$Me2CO$3EtOH represents a bent double-decker sandwich in the
crystal (the dihedral angle between the mean planes of the central
9-membered rings of the macrocycles is 43.0ꢂ). The sulfate anion in
the complex behaves as a tetradentate ligand and coordinates with
each anticrown moiety by two oxygen atoms in an h3 h1 fashion.
:
The HgeO separations in the h3 coordination fragments of the
ꢀ
ꢀ
adduct are in the range of 2.602(9)e2.702(9) A (av. 2.65 A; see
Table 3) and are significantly shorter than the analogous HgeO
separations in complexes 2 (av. 2.92 A) and 3 (av. 2.93 A). The h1
coordination HgeO bonds in 4$Me2CO$3EtOH are formed by the
ꢀ
ꢀ
Table 3
ꢂ
ꢀ
Selected bond lengths (A) and angles ( ) in complex 4$Me2CO$3EtOH.
Hg(1)eO(1)
Hg(2)eO(1)
Hg(3)eO(1)
Hg(4)eO(2)
Hg(5)eO(2)
Hg(6)eO(2)
Hg(2)eO(3)
Hg(6)eO(4)
2.647(9)
2.661(10)
2.646(10)
2.602(9)
2.648(8)
2.702(9)
2.978(9)
2.948(10)
108.4(5)
110.2(6)
109.4(7)
S(1)eO(1)
S(1)eO(2)
S(1)eO(3)
S(1)eO(4)
O(1S)/O(3)
O(2S)/O(4)
O(3S)/O(2S)
1.468(9)
1.474(9)
1.455(10)
1.483(11)
2.75(1)
Table 2
ꢂ
ꢀ
Selected bond lengths (A) and angles ( ) in complex 3.
Hg(1)eO(1)
Hg(2)eO(1)
Hg(3)eO(1)
Hg(4)eO(2)
Hg(5)eO(2)
Hg(6)eO(2)
O(1)eN(1)eO(2)
O(1)eN(1)eO(3)
2.688(3)
2.835(3)
3.276(3)
2.832(3)
2.924(3)
3.001(3)
120.3(4)
119.2(4)
Hg(3)eO(3)
Hg(6)eO(3)
N(1)eO(1)
N(1)eO(2)
N(1)eO(3)
2.885(3)
2.723(3)
1.254(4)
1.245(4)
1.248(5)
2.61(2)
2.87(3)
O(1)eS(1)eO(2)
O(1)eS(1)eO(3)
O(1)eS(1)eO(4)
O(2)eS(1)eO(3)
O(2)eS(1)eO(4)
O(3)eS(1)eO(4)
110.4(6)
108.6(6)
109.8(6)
O(2)eN(1)eO(3)
120.5(3)

170
K.I. Tugashov et al. / Journal of Organometallic Chemistry 747 (2013) 167e173
oxygen atoms O(3) and O(4) which interact with the Hg(2) and
the atoms of the cationic and anionic parts of the complexes, which
would explain the above-mentioned difference in the geometry of
the sandwich moieties. Therefore, one may conclude that the
observed difference is the result of packing effects which are
assisted by secondary character of the HgeO coordination bonds in
these supramolecular adducts.
In the case of sulfate anions, two complexes (4 and 5) dis-
tinguishing by the nature of a countercation were obtained as well
however the X-ray diffraction study could be carried out only for
complex 4 in a form of its solvate 4$Me2CO$3EtOH. The complex
contains H-bonds between two oxygen atoms of the coordinated
sulfate anion and two ethanol molecules and, like 3, represents a
bent sandwich.
Hg(6) atoms respectively. The corresponding Hg(2)eO(3) and
ꢀ
Hg(6)eO(4) separations (2.978(9) and 2.948(10) A) are consider-
ably shorter than the analogous HgeO separations in 2 (3.137(8)
ꢀ
and 3.543(8) A) but noticeably longer than those in 3 (2.885(3) and
ꢀ
2.723(3) A).
The h1 coordinated oxygen atoms O(3) and O(4) of the sulfate
anion in 4$Me2CO$3EtOH are involved also in the formation of H-
ꢀ
bonds with two ethanol molecules (O(1S)/O(3) 2.75(1) A, O(2S)/
ꢀ
O(4) 2.61(2) A). In its turn, one of these molecules forms H-bond
with the third ethanol species in the complex (O(3S)/O(2S)
ꢀ
2.87(3) A).
The coordinated sulfate anion retains its tetrahedral configura-
ꢀ
tion and the SeO distances in the complex (1.455(10)e1.483(11) A;
A
comparison of the synthesized complexes 2,
3 and
av. 1.47 A) are close to the length of the SeO bonds in free SO24ꢀ ion
4$Me2CO$3EtOH shows that the shortest HgeO distances
ꢀ
ꢀ
ꢀ
ꢀ
(1.472 A [32]).
(2.602(9)e2.702(9) A; av. 2.65 A) are realized here in the case of the
h
The only known complex of an anticrown with sulfate anion has
been obtained for the five-mercury macrocycle [(CF3)2CHg]5 con-
taining the Hg atoms in a planar ten-membered ring [4]. The sulfate
anion in this 1:1 complex {[(CF3)2CHg]5(SO4)}2ꢀ serves again as a
tetradentate ligand but coordinates to the anticrown molecule in an
3 coordination fragments of 4$Me2CO$3EtOH. These distances are
considerably shorter than the HgeO bond lengths in all presently
known complexes of 1 with oxygenous Lewis bases (aldehydes and
ꢀ
ketones, 2.810(12)e3.088(8) A [37e39]; organic amides, 2.777(4)e
ꢀ
ꢀ
3.024(5) A [40e42]; ethyl acetate, 2.848(5)e2.975(5) A [41]; HMPA,
h5
:
h2
:
h1
:
h
1 fashion. One more interesting feature of the complex is
2.824(4)e2.895(4) A [41]; DMSO, 2.759(5)e3.120(5) A [41]; THF,
2.853(3)e3.621(9) A [14]; etc. [14,15,19]). The Hg(1)eO(1) and
Hg(3A)eO(2) bonds in 2 (2.676(6) and 2.708(6) A) and the Hg(1)e
O(1) bond in 3 (2.688(3) A) are also significantly shortened but the
ꢀ
ꢀ
the arrangement of the h5 coordinated oxygen atom of the sulfate
anion virtually in the plane of the ten-membered mercuracarbon
ring.
ꢀ
ꢀ
ꢀ
In the crystal, the anionic parts of complexes
3
and
other HgeO distances in these nitrate complexes are comparable
on the whole with those in the above-mentioned complexes of 1
with oxygenous Lewis bases.
The synthesized sandwich compounds 2, 3 and 4$Me2CO$3EtOH
are the novel structural type of complexes of nitrate and sulfate
anions with an anticrown as well as the first examples of struc-
turally characterized complexes of 1 with oxygen-containing
anions.
4$Me2CO$3EtOH form extended stacks due to shortened (as
compared to the sum of the van der Waals radii) intermolecular
Hg/Hg, Hg/C and C/C contacts between the neighboring sand-
ꢀ
wichunits of the adduct(3: Hg/Hg 3.5570(2)and 3.8250(2)A, Hg/C
ꢀ
ꢀ
3.295(4)e3.712(4) A, C/C 3.299(6)e3.517(6) A; 4$Me2CO$3EtOH:
ꢀ
ꢀ
Hg/Hg 3.754 (1) A, Hg/C 3.40(1)e3.68(1) A, C/C 3.35(2)e
ꢀ
3.53(3) A). The stacks are disposed along c crystal axis in the case of 3
and along b crystal axis in the case of 4$Me2CO$3EtOH. The distance
between the mean planes of the central Hg3C6 rings of the adjacent
4. Experimental
ꢀ
ꢀ
mercuramacrocycles in the stack is 3.412 A in 3 and 3.51 A in
4$Me2CO$3EtOH. The formation of similar stacks was earlier
observed in the crystal structures of the double-decker sandwich
The starting macrocycle 1 was prepared according to the pub-
lished procedure [23a]. Commercial bis(triphenylphosphor-
anylidene)ammonium chloride [PPN]Cl (Aldrich; 97%), phenyltri-
methylammonium iodide [PhNMe3]I (Chemapol Prague), tetraphe-
nylphosphonium bromide [PPh4]Br (Chemapol Prague), triphe-
nylmethylphosphonium iodide [PPh3Me]I (Chemapol Prague),
anhydrous potassium nitrate, silver sulfate and silver nitrate were
used without an additional purification. Solvents were purified by
conventional methods and freshly distilled prior to use over calcium
hydride (ethanol, acetone), P2O5 (CH2Cl2), metallic sodium (n-hex-
ane) or LiAlH4 (Et2O) under Ar. The 199Hg NMR spectra were recorded
on a Bruker Av-600 instrument using a 0.2 M solution of Ph2Hg in
2ꢀ
2ꢀ
,
complexes of
1
with closo-[B10H10
]
,
closo-[B12H12
]
closo-
[B12H11SCN]2ꢀ, [Fe(CN)6]3ꢀ and [Fe(CN)5(NO)]2ꢀ anions [27e29] as
well as with metallocenes [35,36] p-benzoquinone [37], [9]
thiacrown-3[10] and [12]crown-4[15]. As in the case of 2, the anti-
crown units in the crystal structures of 3 and 4$Me2CO$3EtOH form
also shortened CeF/H contacts (2.40e2.59 A in 3, 2.41e2.58 A in
4$Me2CO$3EtOH) with the CeH bonds of the countercations.
The complexation of 1 with nitrate and sulfate anions does not
affect essentially the geometry of the macrocycle. The HgeC bond
ꢀ
ꢀ
ꢀ
lengths in 2 (2.069(3)e2.080(4) Å), 3 (2.064(5)e2.085(4) A) and
ꢀ
4$Me2CO$3EtOH (2.04(2)e2.10(2) A) are unexceptional. The Ce
pyridine (
d
¼ ꢀ791.1 ppm [43]) as an external standard. The IR spectra
HgeC bond angles, as in free 1, are close to 180ꢂ (175.3(2)e
175.9(2)ꢂ in 2, 174.5(2)e176.8(2)ꢂ in 3, 172.6(7)e175.5(6)ꢂ in
4$Me2CO$3EtOH).
of complexes were recorded as Nujol mulls on a Nicolet Magna-IR 750
Series II Fourier spectrometer.
3. Conclusion
4.1. Synthesis of [PPN]NO3$H2O
The results of our study demonstrate the ability of the three-
mercury anticrown 1 to bind nitrate and sulfate anions with the
formation of double-decker sandwich complexes. In the case of
nitrate anions, two complexes 2 and 3 differing from each other by
the nature of a countercation were prepared and structurally
characterized. The nitrate anion in these complexes is bonded to
the molecules of 1 in a similar fashion but whereas complex 3 has a
bent sandwich geometry in the crystal the planes of the anticrown
units in 2 are parallel to one another. A more detailed analysis of the
structures of 2 and 3 did not reveal any bonding contacts between
To a solution of [PPN]Cl (0.287 g, 0.5 mmol) in a mixture of
water (15 mL) and ethanol (2 mL) was added upon stirring at room
temperature a solution of KNO3 (0.051 g, 0.5 mmol) in water
(2 mL). Immediately, a white powder of [PPN]NO3$H2O began to
precipitate. Then, the reaction mixture was stirred for 1 h, the
resulting [PPN]NO3$H2O was filtered off, washed with water
(3 ꢁ 2 mL) and dried at 20 ꢂC in vacuum for 5 h. Yield: 0.302 g
(98%). Anal. Calcd. for C36H32N2O4P2 (%): C, 69.90; H, 5.21; N, 4.53.
Found: C, 70.03; H, 4.84; N, 4.31. IR (nOH, cmꢀ1): 3530 (br), 3462
(br).

K.I. Tugashov et al. / Journal of Organometallic Chemistry 747 (2013) 167e173
171
Table 4
Crystal data, data collection and structure refinement parameters for 2, 3 and 4$Me2CO$3EtOH.
2
3
4$Me2CO$3EtOH
Formula
C72H30F24Hg6N2O3P2
2692.46
0.36 ꢁ 0.31 ꢁ 0.16
Triclinic
Pl
9.0108(4)
10.6179(5)
18.1790(9)
101.593(1)
101.252(1)
93.165(1)
1663.0(1)
1
C60H20F24Hg6NO3P
2493.28
0.27 ꢁ 0.15 ꢁ 0.15
Monoclinic
P21/c
12.0036(3)
26.3521(7)
18.8943(5)
90
95.094(1)
90
5953.0(3)
4
C63H52F24Hg6N2O8S
2656.67
0.22 ꢁ 0.07 ꢁ 0.06
Monoclinic
P21/n
17.062(2)
17.549(2)
23.481(2)
90
91.015(2)
90
7030(1)
4
Molecular weight
Crystal size (mm3)
Crystal system
Space group
ꢀ
a (A)
ꢀ
b (A)
ꢀ
c (A)
a
b
g
(ꢂ)
(ꢂ)
(ꢂ)
3
ꢀ
V (A )
Z
rcalc (g cmꢀ3
)
2.689
13.965
2.782
15.566
2.510
13.203
Linear absorption (
m
), mmꢀ1
Tmin/Tmax
2
0.029/0.215
64
0.056/0.233
64
0.252/0.505
54
qmax (ꢂ)
No. unique refl. (Rint
No. observed refl. (I > 2s(I))
)
11,488 (0.0403)
9413
20,633 (0.0667)
16,130
15,224 (0.0935)
9206
No. parameters
514
0.0265
0.0525
0.995
856
0.0281
0.0568
1.006
940
0.0550
0.1293
1.036
R1 (on F for observed refl.)a
wR2 (on F2 for all refl.)b
GOOF
a
R1 ¼ SrrFor ꢀ rFcrr/SrFor.
b
wR2 ¼ {S[w(F2o ꢀ F2c)2]/S[w(Fo2)2]}1/2
.
4.2. Synthesis of [PPh4]NO3
2.0 mmol) in 10 mL of water. Immediately, a yellow powder of
AgI began to precipitate. The reaction mixture was stirred in
darkness for 1 h and filtered off, the colorless filtrate was evap-
orated at 20 ꢂS in vacuum and the resulting resinous product
To a solution of [PPh4]Br (0.42 g, 1.0 mmol) in a mixture of water
(18 mL) and ethanol (2 mL) was added upon stirring at room
temperature a solution of AgNO3 (0.17 g, 1.0 mmol) in water (2 mL).
Immediately, a yellowish powder of AgBr began to precipitate. The
reaction mixture was stirred in darkness for 1 h, then it was
centrifuged for 10 min at 5000 rpm and filtered off. The resulting
colorless filtrate was concentrated to w2 mL in vacuum and then
kept overnight in refrigerator. The next day, the precipitated
colorless crystals of [PPh4]NO3 were filtered off, washed with cold
water (4 ꢁ 0.5 mL) and dried at 20 ꢂC in vacuum for 5 h. Yield:
0.33 g (82%). Anal. Calcd. for C24H20NO3P (%): C, 71.81; H, 5.02; N,
3.49; P, 7.72. Found: C, 71.96; H, 4.88; N, 3.46; P, 7.72.
The synthesis of [PPh4]NO3 by combining hot solutions of
ethanolic [PPh4]Br and aqueous AgNO3 has been previously
described very shortly in Ref. [44]. However elemental analysis data
for the product obtained and its isolated yield are not reported in
this article.
was dried at 70e80 ꢂS in vacuum for 2 h to give [PhNMe3]2
-
SO4$3H2O as a colorless crystalline solid. Yield: 0.382 g (90%).
Anal. Calcd. for C18H34N2O7S (%): C, 51.17; H, 8.11; N, 6.63. Found:
C, 51.31; H, 8.18; N, 6.55. IR (nOH, cmꢀ1): 3370 (br). The synthe-
sized compound is hygroscopic and should be kept in desiccator
over NaOH or P2O5.
4.5. Synthesis of [PPN]{[(o-C6F4Hg)3]2(NO3)} (2)
To a solution of macrocycle 1 (0.1032 g, 0.1 mmol) in ethanol
(8 mL) was added at room temperature a solution of [PPN]
NO3$H2O (0.0303 g, 0.05 mmol) in ethanol (4 mL). Within 2 h, a
colorless crystalline complex 2 began to precipitate. The next day,
the reaction mixture was slowly concentrated for 6 h to 2 mL and
the resulting 2 was filtered off, washed with ethanol (3 ꢁ 0.5 mL)
and diethyl ether (3 ꢁ 0.5 mL) and dried at 20 ꢂS in vacuum for
3.5 h. Yield: 0.0806 g (61%). Anal. Calcd. for C72H30F24Hg6N2O3P2
(%): C, 32.12; H, 1.12; F, 16.93. Found: C, 32.48; H, 0.94; F, 16.87.
Single crystals of 2 for the X-ray diffraction study were grown
from the acetone/ethanol mixture (1:2) and were not dried in
vacuum.
4.3. Synthesis of [PPh3Me]2SO4$2H2O
To a solution of [PPh3Me]I (0.40 g, 1.0 mmol) in a mixture of
water (15 mL) and ethanol (1.5 mL) was added upon stirring a
suspension of Ag2SO4 (0.15 g, 0.5 mmol) in water (3 mL). Immedi-
ately, a yellow powder of AgI began to precipitate. The reaction
mixture was stirred for 2.5 h in darkness and filtered off. The
colorless filtrate was evaporated in vacuum, the resulting resinous
product was washed with acetone (3 ꢁ 5 mL) and kept under
acetone in refrigerator overnight to give a white powder of
[PPh3Me]2SO4$2H2O which was filtered off, washed with acetone
(2 ꢁ 1 mL) and dried at 20 ꢂC in vacuum for 3 h. Yield: 0.31 g (95%).
Anal. Calcd. for C38H40O6P2S (%): C, 66.46; H, 5.87; P, 9.02. Found: C,
66.88; H, 5.93; P, 8.99. IR (nOH, cmꢀ1): 3412 (br), 3375 (br).
4.6. Synthesis of [PPh4]{[(o-C6F4Hg)3]2(NO3)} (3)
To a solution of 1 (0.1045 g, 0.1 mmol) in ethanol (2 mL) was
added a solution of [PPh4]NO3 (0.0198 g, 0.05 mmol) in ethanol
(4 mL). Within 45 min, colorless crystals of complex 3 began to
precipitate. After 2 h, the reaction mixture was slowly concentrated
for 12 h to 1 mL, the resulting crystals of 3 were filtered off, washed
with ethanol (3 ꢁ 0.5 mL) and n-hexane (2 ꢁ 1 mL) and dried at
20 ꢂC in vacuum for 3 h. Yield: 0.0810 g (66%). Anal. Calcd. for
C60H20F24Hg6NO3P (%): C, 28.90; H, 0.81; F, 18.29. Found: C, 28.67;
H, 0.76; F, 18.07. Single crystals of 3 for the X-ray diffraction study
were grown from the acetone/ethanol mixture (1:2) and were not
dried in vacuum.
4.4. Synthesis of [PhNMe3]2SO4$3H2O
To a suspension of Ag2SO4 (0.313 g, 1.0 mmol) in 20 mL of
water was added upon stirring a solution of [PhNMe3]I (0.526 g,

172
K.I. Tugashov et al. / Journal of Organometallic Chemistry 747 (2013) 167e173
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4.7. Synthesis of [PhNMe3]2{[(o-C6F4Hg)3]2(SO4)} (4)
To a suspension of [PhNMe3]2SO4$3H2O (0.0214 g, 0.05 mmol) in
CH2Cl2 (2 mL) was added upon stirring a solution of 1 (0.1047 g,
0.1 mmol) in CH2Cl2 (15 mL). Within 10 min, the reaction mixture
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the resulting 4 was filtered off, washed with CH2Cl2 (3 ꢁ 1 mL) and
water (2 ꢁ 1 mL) and dried at 100e120 ꢂC in vacuum for 3 h. Yield:
0.0965 g (78%). Anal. Calcd. for C54H28F24Hg6N2O4S (%): C, 26.36; H,
1.15; F, 18.53. Found: C, 26.50; H, 1.35; F, 18.40. Single crystals of 4
for the X-ray diffraction study were grown from the acetone/
ethanol mixture (1:1) and were not dried in vacuum. The crystals
had composition 4 Me2CO$3EtOH according to X-ray crysta-
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To a solution of macrocycle 1 (0.1084 g, 0.1 mmol) in CH2Cl2
(15 mL) was added a solution of [PPh3Me]2SO4$2H2O (0.0358 g,
0.05 mmol) in CH2Cl2 (2 mL). Within 30 min, the reaction mixture
became turbid and colorless needles of complex 5 began to pre-
cipitate. After 4 h, the resulting 5 was filtered off, washed with
CH2Cl2 (3 ꢁ 0.5 mL) and dried at 20 ꢂC in vacuum for 2 h. Yield:
0.1056 g (74%). Anal. Calcd. for C74H36F24Hg6O4P2S (%): C, 32.41; H,
1.32; P, 2.26. Found: C, 32.48; H, 1.19; P, 2.09.
4.9. X-ray diffraction study
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Single-crystal X-ray diffraction experiments were carried out
with a Bruker SMART APEX II diffractometer (graphite mono-
ꢀ
chromated Mo K
a
radiation,
l
¼ 0.71073 A,
u-scan technique,
T ¼ 100 K). The APEX II software [45] was used for collecting frames
of data, indexing reflections, determination of lattice constants,
integration of intensities of reflections, scaling and absorption
correction while SHELXTL [46] was applied for space group and
structure determination, refinements, graphics and structure
reporting. The structures were solved by direct methods and
refined by the full-matrix least-squares technique against F2 with
the anisotropic thermal parameters for all non-hydrogen atoms.
The hydrogen atoms were placed geometrically and included in the
structure factors calculations in the riding motion approximation.
The main experimental and crystallographic parameters are pre-
sented in Table 4.
Acknowledgment
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(b) P. Pyykkö, M. Straka, Phys. Chem. Chem. Phys. 2 (2000) 2489;
(c) S.S. Batsanov, Zh. Neorg. Khim. 36 (1991) 3015;
This work was supported by the Russian Foundation for Basic
Research (Project codes 12-03-00427 and 13-03-01176).
(d) S.C. Nyburg, C.H. Faerman, Acta Crystallogr. Sect. B 41 (1985) 274.
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Appendix A. Supplementary material
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Engl. 53 (2004) 2871.
CCDC 926086, 926087 and 926088 contain the supplementary
crystallographic data for this paper. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre via
http://www.ccdc.cam.ac.uk/data_request/cif.
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