New Bis-o-Benzoquinoid ligands with ethylene bridge and their metal complexes

Article abstract of DOI:10.1002/zaac.200900282

The treatment of di-o-quinone 4,4′-(ethane-1,2-diyl)-bis(3,6-di-tert- butyl-o-benzoquinone) (Q-CH₂-CH₂-Q, 1) leads to its rearrangement to form di-p-quinomethide 4,4′-(ethane-1,2-diylidene)bis(2- hydroxy-3,6-di-tert-butyl-cyclohexa-2

Full text of DOI:10.1002/zaac.200900282

ARTICLE
DOI: 10.1002/zaac.200900282
New BisꢀoꢀBenzoquinoid Ligands with Ethylene Bridge and Their Metal
Complexes
Andrey I. Poddel’sky,*[a] Alexander V. Piskunov,[a] Nikolay O. Druzhkov,[a]
Georgii K. Fukin,[a] Vladimir K. Cherkasov,[a] and Gleb A. Abakumov[a]
Keywords: O,O ligands; oꢀQuinone; Antimony; NMR spectroscopy; Xꢀray diffraction
Abstract. The treatment of diꢀoꢀquinone 4,4'ꢀ(ethaneꢀ1,2ꢀdiyl)ꢀbis(3,6ꢀ sium, thallium was studied by EPR technique. The dinuclear thallium
diꢀtertꢀbutylꢀoꢀbenzoquinone) (Q–CH2–CH2–Q, 1) leads to its rearꢀ derivative of 3, Tl(SQ–CH=CH–SQ)Tl, was found to exist in the diaꢀ
rangement to form diꢀpꢀquinomethide 4,4'ꢀ(ethaneꢀ1,2ꢀdiylidene)bis(2ꢀ magnetic quinomethide form. The most stable derivatives of 2 and 3
hydroxyꢀ3,6ꢀdiꢀtertꢀbutylꢀcyclohexaꢀ2,5ꢀdienone) (2). The subsequent are triphenyltin(IV) bisꢀpꢀquinomethideꢀphenolate (4) and triphenylanꢀ
oxidation of 2 by an alkaline solution of K3[Fe(CN)6] yielded the new timony(V) bisꢀcatecholate (5), which have been synthesized and isoꢀ
diꢀoꢀquinone 4,4'ꢀ(etheneꢀ1,2ꢀdiyl)bis(3,6ꢀdiꢀtertꢀbutylꢀoꢀbenzoquinꢀ lated. The molecular structures of 2, 3, and 5 were characterized by
one) (Q–CH=CH–Q, 3), which contains an ethylene bridge. The forꢀ
mation of monoꢀ and polyꢀreduced derivatives of 2 and 3 with potasꢀ
singleꢀcrystal Xꢀray diffraction.
based on indeno[1,2]indene (D) [4d] and 4,4ꢀbisꢀoꢀbenzoquinꢀ
ones (E) [4e, f]. The next type of bisꢀoꢀbenzoquinones is preꢀ
sented by 4,4'ꢀ(ethaneꢀ1,2ꢀdiyl)ꢀbis(3,6ꢀdiꢀtertꢀbutylꢀoꢀbenzoꢀ
quinone) (Q–CH2–CH2–Q, 1) [5].
1. Introduction
An important area in modern coordination chemistry is the
search of compounds that act as molecular magnetic materials
[1]. Redoxꢀactive dioxolene ligands such as oꢀquinones and
related compounds are prospective objects for the composition
of molecules with novel electronic structures [2]. The diversity
of electronic structures of the formed complexes is influenced
by the three different forms of such ligands: quinone, semiꢀ
quinone and catecholate. Transition metal semiquinone comꢀ
plexes are interesting in the viewpoint of investigating their
intraꢀ and intermolecular electronic and magnetic interactions
(metalꢀligand, ligandꢀligand etc.). The integration of two and
more semiquinone moieties in one organic tetraꢀ or hexadenꢀ
tate ligand allows the formation of polynuclear structures and
the organization of new molecular magnetic exchange chanꢀ
nels, which are impossible for the derivatives of simple oꢀquinꢀ
ones [3]. Therefore, the synthesis of novel bisꢀ or trisꢀoꢀquinoꢀ
nes is expected to be important for the preparation of
complexes revealing new interesting magnetic and electronic
properties. Along these investigations, a number of different
bisꢀoꢀquinones were synthesized and characterized [3, 4].
Among them (Scheme 1) are bisꢀoꢀquinones such as 1,1'ꢀspiroꢀ
bis(3,3ꢀdimethylindanequinoneꢀ5,6) (A) [4a]; pꢀterphenyldiꢀ
quinoneꢀ3,4,3',4’ (B) [4b], bisꢀoꢀquinones (C) with a linker L,
which affects the conformation and, consequently, exchange
coupling of semiquinone derivatives [4c]; a bisꢀoꢀquinone
Scheme 1.
* Prof. Dr. A. I. Poddel’sky
In this paper we report on the synthesis and characterization
of bisꢀoꢀquinones containing ethylene bridge between oꢀbenzoꢀ
quinone parts, and their reduced derivatives, particularly the
tetra electron reduced derivative bisꢀtriphenylantimony(V) bisꢀ
catecholate.
Fax: +7ꢀ831ꢀ462ꢀ74ꢀ97
EꢀMail: aip@iomc.ras.ru
[a] G. A. Razuvaev Institute of Organometallic Chemistry
Russian Academy of Sciences
Tropinina 49
603950 Nizhny Novgorod GSPꢀ445, Russian Federation
Z. Anorg. Allg. Chem. 2009, 635, 2563–2571
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
2563

A. I. Poddel’sky et al.
ARTICLE
ing vibrations of the OH groups in 2 give a signal at
3213 cm–1. It allows the assumption of intramolecular interacꢀ
tions between hydroxyl and carbonyl groups. The Xꢀray studꢀ
ies corroborate this supposition (see below).
2. Results and Discussion
2.1. Synthesis and Characterization
Diꢀoꢀquinone 4,4'ꢀ(ethaneꢀ1,2ꢀdiyl)ꢀbis(3,6ꢀdiꢀtertꢀbutylꢀoꢀ
benzoquinone) (QꢀCH2–CH2–Q, 1) rearranged into 4,4'ꢀ(ethꢀ
aneꢀ1,2ꢀdiylidene)bis(2ꢀhydroxyꢀ3,6ꢀdiꢀtertꢀbutylꢀcyclohexaꢀ
2,5ꢀdienone) (2) upon it was treated in toluene for 4 hours at
70 °C (Scheme 2).
2.2. Crystal Structures of 2 and 3
The crystal structures of 2 and 3 were determined by singleꢀ
crystal Xꢀray diffraction (Figure 1 and Figure 2, respectively).
The selected bond lengths and angles of 2 are listed in Table 1.
Scheme 2.
Compound 2 was isolated from dioxane as deep colored
crystalline powder, which is stable in air. The color of the
amorphous powder of 2 is cherryꢀred. It is hardly soluble in
common organic solvents, but reasonably soluble in dioxane.
Its crystal structure was determined by Xꢀray diffraction studꢀ
ies.
Subsequent oxidation of 2 by alkaline solution of potassium
hexacyanidoferrate gives new diꢀoꢀquinone 4,4'ꢀ(etheneꢀ1,2ꢀ
diyl)bis(3,6ꢀdiꢀtertꢀbutylꢀoꢀbenzoquinone) (Q–CH=CH–Q, 3)
(Scheme 3). Dark red crystals of 3 suitable for Xꢀray analysis
were grown from a toluene solution.
Figure 1. PLATON [6] view of 2. Hydrogen atoms of tertꢀbutyl groups
and the rings are omitted for clarity.
In the crystal structure of 2, the molecules are disposed in
an inversion center. The quinomethide structure of 2 is corrobꢀ
orated by pꢀquinoid type distortion: the carbon–carbon bonds
C(2)–C(3) and C(5)–C(6) are of double character and distinctly
shorter than the ordinary C(1)–C(2), C(3)–C(4), C(4)–C(5) and
C(1)–C(6) bonds (Scheme 4). Scheme 4 also shows the strucꢀ
ture of related diethylstilbestrolquinone [7] to compare the
quinomethide fragments of these molecules. The difference in
the C=C bond lengths in the cyclohexadiene and methylene
fragments of these molecules, and also in the C–C bond
lengths of the bridging chain is obvious. In the case of diethylꢀ
Scheme 3.
Compounds 2 and 3 were characterized by NMR and IR stilbestrolquinone, the ordinary C–C bond length (1.469 Å) of
spectroscopy. Noteworthy, both compounds 2 and 3 have a the C=C–C=C moiety tends to a value of 1.478(12) Å, which
1
symmetrical structure in solution in accordance with their H is usual for unconjugated units [8], whereas the same bond
1
and 13C NMR spectra. The H NMR spectrum of 2 contains length in 2 [1.406(10) Å] is shorter than even in butadiene.
two singlet signals assigned to two pairs of nonequivalent tertꢀ This observation can be rationalized by a different conjugation
butyl proton groups at 1.35 and 1.61 ppm and the integral inꢀ degree. In contrast to the nonplanar diethylstilbestrolquinone
tensity of 18 protons per singlet. Two equivalent ring protons molecule [7], compound 2 is planar, and thus, both quinomeꢀ
appear as singlet signal at 8.20 ppm whereas two protons of thide fragments are strongly conjugated. The torsion angle
a =CH–CH= bridging moiety give a singlet signal at 7.68 ppm. O(1)–C(1)–C(2)–O(2) is only 1.29(4)°.
Another singlet signal at 8.15 ppm is assigned to hydroxyl proꢀ
The C(2)–O(2) distance of 1.357(6) Å is close to the ordiꢀ
1
tons. The H NMR spectrum of 3 shows two singlet signals nary C–O bond lengths in different phenols (1.359–1.362 Å)
from two pairs of tertꢀbutyls protons (1.27 and 1.42 ppm), one [8], it evidences the hydroxyl character of this group. The
singlet signal from two benzoquinone protons (7.27 ppm) and O(1)···H(2) distance [1.78(2) Å] is shorter than the sum of Van
one singlet signal from ethylene protons (6.95 ppm).
der Waals radii of hydrogen and oxygen atoms (2.7 Å [9]) or
The comparison of the IR spectra of 2 and 3 gives interesting close intramolecular O···H (2.15 Å) contacts [10]. Thus, the
results. The absorption bands of the carbon–oxygen vibrations intramolecular hydrogen bond is realized in molecule 2. The
v(C=O) for 3 are observed at 1676 and 1648 cm–1. In the case O(1)–C(1)–C(2)–O(2)–H(2) fragment is practically planar, the
of quinomethide 2, those are shifted to 1591 cm–1. The stretchꢀ mean deviation from plane is 0.033 Å.
2564
www.zaac.wileyꢀvch.de
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 2563–2571

BisꢀoꢀBenzoquinoid Ligands with Ethylene Bridge and Their Metal Complexes
Figure 2. PLATON view of two independent molecules of 3. Hydrogen atoms of tertꢀbutyl groups and the rings are omitted for clarity.
Table 1. Selected bond lengths /Å and angles /° in 2.
C(4), C(5)–C(6) and C(10)–C(11), C(9)–C(14) in A and
C(33)–C(34), C(35)–C(36) in B] are separated by an ordinary
C–C bond [C(4)–C(5), C(9)–C(10) in A, and C(34)–C(35) in
B]. Carbon–oxygen bonds [O(1)–C(1) 1.215(2) Å, O(2)–C(2)
1.213(2) Å, O(3)–C(12) 1.217(2) Å, O(4)–C(13) 1.221(2) Å
in A; O(5)–C(32) 1.218(2) Å, O(6)–C(31) 1.220(2) Å in B]
are of double bond character and are in the range of usual
carbonyl bonds of carbonyl compounds 1.19–1.23 Å [8, 11].
In crystals of 3,5ꢀdiꢀtertꢀbutylꢀoꢀbenzoquinone, double C=C
bonds are 1.347, 1.348 Å, C=O bonds are 1.221, 1.223 Å [12].
The double [1.341–1.343(2) Å] and ordinary [1.471(2),
1.467(2) Å in A and 1.463(2) Å in B] carbon–carbon bond
lengths of the ethylene bridge in both molecules A and B in 3
(Table 2) are similar to those in compounds with a C=C–C=C
fragment (C=C, 1.331–1.341 Å; C–C, 1.460–1.470 Å) [8]. In
contrast to the molecular structure of 2, the C–O groups in
both molecules of 3 are twisted against each other. The torsion
angles O(1)–C(1)–C(2)–O(2), O(3)–C(12)–C(13)–O(4) in the
first molecule of 3 and O(5)–C(33)–C(34)–O(6) in the second
molecule of 3 are 22.82(15), 34.55(15) and 23.34(15)°, respecꢀ
tively.
bond /Å
angle /°
O(1)–C(1)
O(2)–C(2)
C(1)–C(6)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(3)–C(8)
C(4)–C(7)
C(4)–C(5)
C(5)–C(6)
C(6)–C(12)
C(7)–C(7a)
1.246(6)
1.357(6)
1.446(7)
1.486(7)
1.361(7)
1.451(7)
1.544(7)
1.391(7)
1.452(7)
1.342(6)
1.528(7)
1.406(10)
O(1)–C(1)–C(6)
O(1)–C(1)–C(2)
C(6)–C(1)–C(2)
O(2)–C(2)–C(3)
O(2)–C(2)–C(1)
C(3)–C(2)–C(1)
C(7)–C(4)–C(5)
C(7)–C(4)–C(3)
C(5)–C(4)–C(3)
C(6)–C(5)–C(4)
C(5)–C(6)–C(1)
C(4)–C(7)–C(7a)
124.8(4)
115.9(4)
119.3(4)
125.1(4)
110.3(4)
124.6(4)
116.8(4)
122.4(4)
120.7(4)
125.2(4)
115.7(4)
127.4(6)
It should be noted that the shortened O···H distances between
oxygen atoms and hydrogen atoms of tertꢀbutyl groups are
found in both molecules. These distances vary in the range
of 2.30(2)–2.44(2) Å in 2 and 2.30(2)–2.41(2) Å in 3 and are
significantly shorter than the sum of Van der Waals radii of
aboveꢀmentioned atoms. However, we observed a twist conforꢀ
mation of the C–O groups for 3 but not for 2 (the molecule is
practically planar). Apparently, the main reason for this strucꢀ
tural difference in molecules 2 and 3 is the formation of an
intramolecular O···H hydrogen bond in 2. In other words, the
intramolecular O···H bond in 2 gives additional hardness (staꢀ
bility) of the O(1)–C(1)–C(2)–O(2) fragments in 2 relative to
analogous fragments in 3. Consequently, the energy of interꢀ
molecular O···H interactions in 2 should be lower than the enꢀ
ergy of the O(1)–H(2) bond. In order to check this assumption,
we carried out DFT calculations with the PCꢀGamess (Firefly)
Scheme 4.
Selected bond lengths and angles in the molecular structure
of compound 3 are given in Table 2. The crystals of 3 contain
two crystallographically independent molecules in the unit cell,
the first molecule is in common position (A) and the other
molecule is disposed on the C2 axis (B). Both molecules reveal
the usual oꢀquinoid distortion: two double C=C bonds [C(3)– program [13]. These calculations showed that the planar
Z. Anorg. Allg. Chem. 2009, 2563–2571
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wileyꢀvch.de 2565

A. I. Poddel’sky et al.
ARTICLE
Table 2. Selected bond lengths /Å and angles /° in 3.
which is close to the energy of the similar hydrogen bonds in
2. However, the absence of an additional stabilization of the
O–C–C–O fragment leads to the twisted conformation of this
fragment in 3, which is due to Pauli repulsion between the two
carbonyl groups.
bond /Å
angle /°
First independent molecule of 3 (A)
O(1)–C(1)
O(2)–C(2)
O(3)–C(12)
O(4)–C(13)
C(1)–C(6)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(4)–C(7)
C(5)–C(6)
C(7)–C(8)
C(8)–C(9)
C(9)–C(14)
C(9)–C(10)
C(10)–C(11)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
1.215(2) O(1)–C(1)–C(6)
124.99(16)
117.22(14)
117.22(14)
124.09(16)
115.95(15)
119.83(13)
121.76(14)
123.29(15)
114.92(14)
124.05(15)
126.33(15)
122.22(15)
122.12(14)
115.45(14)
125.61(16)
117.74(15)
116.64(13)
124.07(16)
116.48(14)
119.28(13)
1.213(2) O(1)–C(1)–C(2)
1.217(2) C(6)–C(1)–C(2)
1.221(2) O(2)–C(2)–C(3)
1.473(2) O(2)–C(2)–C(1)
1.553(2) C(3)–C(2)–C(1)
1.478(2) C(3)–C(4)–C(5)
1.373(2) C(3)–C(4)–C(7)
1.470(2) C(5)–C(4)–C(7)
1.471(2) C(8)–C(7)–C(4)
1.340(2) C(7)–C(8)–C(9)
1.343(2) C(14)–C(9)–C(8)
1.467(2) C(14)–C(9)–C(10)
1.373(2) C(8)–C(9)–C(10)
1.473(2) O(3)–C(12)–C(11)
1.348(2) O(3)–C(12)–C(13)
1.474(2) C(11)–C(12)–C(13)
1.549(2) O(4)–C(13)–C(14)
1.478(2) O(4)–C(13)–C(12)
C(14)–C(13)–C(12)
2.3. EPR Study of the Derivatives of 3
The formation of monoꢀ and polyreduced derivatives is a
well known feature of oꢀquinones and related ligands [4d, 4f,
11, 17].
It was unexpected that some of radicalꢀanionic derivatives of
diꢀoꢀquinone 3 were found to be quite unstable. For instance,
the interaction of 3 with thallium amalgam is accompanied by
a rapid color change to deep violet but, however, the reaction
mixture is EPR silent. The latter fact can be rationalized by
the rearrangement chain including disproportionation of the
mononuclear product and the existence of the diamagnetic
quinomethide salt of the dianionic derivative (Scheme 5).
Second independent molecule of 3 (B)
O(5)–C(32)
O(6)–C(31)
C(31)–C(36)
C(31)–C(32)
C(32)–C(33)
C(33)–C(34)
C(34)–C(45)
C(34)–C(35)
C(35)–C(36)
C(45)ꢀC(45a)
1.218(2) O(6)–C(31)–C(36)
125.11(15)
117.16(14)
117.59(13)
123.78(16)
115.61(14)
120.28(13)
122.88(14)
121.62(14)
115.45(13)
125.68(19)
1.220(2) O(6)–C(31)–C(32)
1.467(2) C(36)–C(31)–C(32)
1.548(2) O(5)–C(32)–C(33)
1.478(2) O(5)–C(32)–C(31)
1.372(2) C(33)–C(32)–C(31)
1.463(2) C(33)–C(34)–C(45)
1.472(2) C(33)–C(34)–C(35)
1.343(2) C(45)–C(34)–C(35)
1.341(3) C(45a)ꢀC(45)–C(34)
framework in 2 and the twisted distortion between the C–O
groups in 3 remained after geometry optimization. The torsion
O–C–C–O angles are 0.14° in 2 and 33.46, 33.42° in 3. Conseꢀ
quently, these phenomena are mainly due to intramolecular inꢀ
teractions than intermolecular interactions in the crystal. In orꢀ
der to understand the nature of these phenomena, we
performed calculations with the application of Bader’s theory
[14, 15]. According to the observed critical points (3,–1), both
complexes have intramolecular hydrogen bonds between the
oxygen atoms of C=O groups and the hydrogen atoms of tBu
groups. There are two O(1)–H(tBu) and one O(2)–C(9) bond
paths in one part of 2ꢀhydroxyꢀ3,6ꢀdiꢀtertꢀbutylꢀcyclohexaꢀ2,5ꢀ
dienone and the same in other part of molecule 2. The same
situation is observed for 3, in which two O(1)ꢀH(tBu) and one
Scheme 5.
The same observations were made when the tetraꢀreduced
O(2)ꢀH(tBu) bond paths exist, the same is observed in the derivative Tl2(Cat–CH=CH–Cat)Tl2 was treated with neutral
other part of the molecule. In order to evaluate the energy of diꢀoꢀquinone 3 (Scheme 5). Despite the amount of 3, there are
these interactions, we used the correlated equation of Espinosa no EPR signals in the reaction mixture although the color
[16]. According to this equation, the energy of intramolecular change reflects the processing of the reaction. This fact implies
O(1)–H(2) hydrogen bond is 12.2 kcal·mol–1 and is noticeably that monoꢀ and triꢀthallium adducts are not stable and undergo
larger than the energy of two intramolecular O(1)–H(tBu) and disproportionation to diamagnetic forms.
one O(2)–C(9) interactions (9.4 kcal·mol–1). Thus, the intramoꢀ
lecular O(1)–H(2) hydrogen bond stabilizes the planar conforꢀ CH–SQ)K , was obtained when an excess of diꢀoꢀquinone (3)
mation in 2. The energy of two O(1)–H(tBu) and one O(2)– was treated with potassium in THF media (Figure 3). The hyꢀ
H(tBu) intramolecular hydrogen bonds in 3 is 8.6 kcal·mol–1, perfine structure (HFS) of spectrum [triplet (1:1:1) of doublets
An EPR spectrum of monoꢀreduced derivative of 3, (Q–CH=
+
˙
2566
www.zaac.wileyꢀvch.de
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 2563–2571

BisꢀoꢀBenzoquinoid Ligands with Ethylene Bridge and Their Metal Complexes
with Ai(2H) = 3.6 G, Ai(H) = 1.95 G, gi = 2.0042] is caused by line darkꢀblue powder precipitated after the solvent change to
unpaired electron hyperfine coupling (HFC) with three protons hexane. By using NMR and IR spectroscopy, it was determined
where two of them are equivalent by pure accident.
as diamagnetic triphenyltin(IV) bisꢀpꢀquinomethideꢀphenolate
(4).
Triphenylstibine is a convenient twoꢀelectron reductant for
oꢀquinones [18]. The addition of a toluene solution of Ph3Sb
to a solution of 3 at room temperature (molar ratio 2:1)
(Scheme 7) effects a color change from greenꢀbrown to deep
yellow within one hour. The crystalline product 5 was obtained
by slow evaporation of the solvent.
Bisꢀcatecholate complex Ph3Sb(Cat–CH=CH–Cat)SbPh3 (5)
has a symmetrical structure in solution, which is corroborated
1
by its H NMR spectrum. The aliphatic region contains two
singlet signals (at 1.44 and 1.59 ppm) assigned to two pairs of
tertꢀbutyl protons, a singlet signal at 6.98 ppm is due to the
ethylene bridge protons. Two protons of aromatic moieties
(fragments C6H1) appear as one singlet signal at 6.76 ppm and
multiplet signals at 7.42–7.50 and 7.74–7.90 ppm are due to
the phenyl protons of triphenylantimony(V) units. The 1H
NMR spectrum also contains signals of the solvent toluene
(singlet at 2.36 ppm and multiplets at 7.15–7.26 ppm).
The symmetrical structure of bisꢀcatecholate 5 maintains in
crystals. Its molecular structure is shown in Figure 4. Selected
bond lengths and angles are listed in Table 3. Xꢀray diffraction
analysis corroborates the presence of coꢀcrystallized solvent:
the unit cell contains one toluene molecule per complex moleꢀ
cule.
Each antimony atom adopts a distorted squareꢀplanar arꢀ
rangement where two oxygen atoms of the catecholate ligand
and two of three phenyl carbon atoms form the basal plane of
the pyramid and the third phenyl carbon atom is in apical posiꢀ
tion. This arrangement was observed for a number of triphenyꢀ
lantimony(V) catecholates [18, 19]. The bond angles at the
basal plane are not equal: O(1)–Sb(1)–C(28) has a value of
144.14(5)° whereas the angle O(2)–Sb(1)–C(16) has
155.53(5)°. The planes of Catꢀligands in CatSbPh3ꢀfragments
are nearly coplanar. At the same time, the plane formed by
ethylene bridge [C(30)–C(15)–C(15')–C(3')] is rotated at
47.13(5)° regarding planes of Catꢀligands. The apical Ph
groups of each SbV catecholate fragment occupy transꢀposiꢀ
tions relatively to each other. The deflection of each antimony
atom from the basal plane O(1)–O(2)–C(16)–C(28) of pyramid
is 0.495(2) Å. The Sb–O bonds [Sb(1)–O(1) 2.0086(11) Å,
Sb(1)–O(2) 2.0381(11) Å] are in good agreement with the sum
of the covalent radii of the corresponding elements (1.41+
0.66 = 2.05 Å [9, 20]).
Figure 3. The Xꢀband EPR spectrum of (Q–CH=CH–SQ)–K+, the reꢀ
˙
duced derivative of 3 with potassium (THF, 298 K) (top spectrum) and
the simulation (bottom spectrum).
The bigger HFS constant (Ai(2H) = 3.6 G) can be attributed
to the ring proton and the second proton of methylene group
whereas the first methylene proton gives rise to the splitting
of 1.95 G. So, the delocalization of an unpaired electron over
˙
both oꢀquinonic fragments in (Q–CH=CH–SQ) takes place.
The presence of additional lines in the EPR spectrum of (Q–
+
˙
CH=CH–SQ)K , which are probably due to cis–trans isomerꢀ
ism of this (Q–CH=CH–SQ) K derivative are noteworthy. The
spin density distribution in cisꢀ and transꢀisomers should be
undoubtedly different from each other. To our regret, the low
concentration of the second product in solution does not allow
to distinguish its spectrum EPR unequivocally.
The oxygen–carbon bond lengths [O(1)–C(1) 1.3653(18),
O(2)–C(6) 1.3579(19) Å] are in the range of ordinary O–C
bond lengths in other triphenylantimony(V) catecholates
(1.34–1.37 Å) [18,19]. The ring carbon–carbon distances of
1.403(2) Å are in average close to aromatic C–C bond lengths
in catecholates [18, 19] or, for instance, in benzene (1.399 Å)
[8].
2.4. Binuclear Tin and Antimony Derivatives of 2 and 3
Diꢀpꢀquinomethide (2) is a suitable starting agent for the
preparation of dianionic derivatives of diꢀoꢀquinone (3). It reꢀ
acts readily with organometallic bases such as Ph3SnOH
The single C–C bond lengths [C(3)–C(15) 1.494(2) Å] of the
ethylene bridge in 5 are elongated relative to those in neutral
(Scheme 6). During the reaction of 2 with Ph3SnOH in THF bisꢀoꢀquinone (3) [1.463(2)–1.471(2) Å], whereas the length
the color of mixture turned to darkꢀviolet, and a microcrystalꢀ of the double bond C(15)–C(15a) [1.314(3) Å] is shorter than
Z. Anorg. Allg. Chem. 2009, 2563–2571
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wileyꢀvch.de
2567

A. I. Poddel’sky et al.
ARTICLE
Scheme 6.
Scheme 7.
Figure 4. PLATON view of 5. Hydrogen atoms of tertꢀbutyl groups and the rings are omitted for clarity.
that of the same bond in 3. They slightly differ from usual
single and double C–C bond lengths (1.51–1.54 and 1.30–
1.33 Å, respectively) [8] because of the formation of a conjuꢀ
gate system in a binuclear molecule.
Investigations on the crystal structure showed that molecules
of 5 are packed in stacks, shifted relatively to each other (Figꢀ
ure 5). Interestingly, hydrogen atoms of apical Ph rings are
directed towards the center of benzene rings of catecholate liꢀ
gands (Tꢀshape arrangement). The “H···center of πꢀsystem”
distance is 2.52(2) Å [the “C–H–center of πꢀsystem” angle is
170.9°; the H···C distances vary in the range of 2.80(3)–
2.98(2) Å]. Apparently, these structural characteristics could
be interpreted as the demonstration of C(H)–πꢀsystem interacꢀ
tions (<3.05 Å [21]).
Table 3. Selected bond lengths /Å and angles /° in 5.
bond /Å
angle /°
Sb(1)–O(1)
Sb(1)–O(2)
Sb(1)–C(22)
Sb(1)–C(28)
Sb(1)–C(16)
O(1)–C(1)
O(2)–C(6)
C(1)–C(6)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(3)–C(15)
C(4)–C(5)
C(5)–C(6)
C(15)ꢀC(15a)
2.0086(11) O(1)–Sb(1)–O(2)
2.0381(11) O(1)–Sb(1)–C(22)
2.0976(14) O(2)–Sb(1)–C(22)
2.1278(15) O(1)–Sb(1)–C(28)
2.1414(15) O(2)–Sb(1)–C(28)
1.3653(18) C(22)–Sb(1)–C(28)
1.3579(19) O(1)–Sb(1)–C(16)
78.42(4)
107.14(5)
98.56(5)
144.14(5)
85.50(5)
106.82(6)
83.28(5)
155.53(5)
102.28(5)
100.44(6)
114.20(13)
121.87(13)
123.93(14)
123.10(13)
115.93(13)
120.97(14)
123.83(19)
1.405(2)
1.406(2)
1.416(2)
1.405(2)
1.494(2)
1.392(2)
1.395(2)
1.314(3)
O(2)–Sb(1)–C(16)
C(22)–Sb(1)–C(16)
C(28)–Sb(1)–C(16)
O(1)–C(1)–C(6)
O(1)–C(1)–C(2)
C(6)–C(1)–C(2)
O(2)–C(6)–C(5)
O(2)–C(6)–C(1)
C(5)–C(6)–C(1)
C(15a)ꢀC(15)–C(3)
We found that the repetition of the reaction between diꢀoꢀ
quinone (3) and triphenylstibine (molar ratio 1:1) did not lead
to mononuclear catecholate Ph3Sb(Cat–CH=CH–Q) in contrast
to 4,4'ꢀbis(3ꢀmethylꢀ6ꢀtertꢀbutylꢀoꢀbenzoquinone) (see type E
of diꢀoꢀquinones on Scheme 1), which was shown to react with
2568
www.zaac.wileyꢀvch.de
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 2563–2571

BisꢀoꢀBenzoquinoid Ligands with Ethylene Bridge and Their Metal Complexes
Figure 5. View of crystal packing fragment of 5. The hydrogen and carbon atoms of tertꢀbutyl groups and hydrogen atoms of the rings are
omitted for clarity.
The intensities data were collected with a SMART APEX diffractomeꢀ
ter (graphiteꢀmonochromated, MoꢀKαꢀradiation, ωꢀ and θꢀscan techꢀ
nique, λ = 0.71073 Å). The structures were solved by direct methods
and were refined on F2 using SHELXTL package [23]. All nonꢀhydroꢀ
gen atoms were refined anisotropically. The hydrogen atoms in 3 and
5 were found from Fourier syntheses of electron density and were
refined isotropically, whereas hydrogen atoms in 2 were placed in calꢀ
culated positions and were refined in the riding model. SADABS [24]
was used to perform areaꢀdetector scaling and absorption corrections.
Summary of crystal and refinement data are presented in Table 4.
Ph3Sb in 1:2 molar ratio forming binuclear bisꢀcatecholate
Ph3Sb(Cat–Cat)SbPh3 and in 1:1 molar ratio forming mononuꢀ
clear Ph3Sb(Cat–Q) [18a]. In our case, reaction of 3 and Ph3Sb
in 1:1 molar ratio yielded the mixture of bisꢀcatecholate (5)
and an initial diꢀoꢀquinone (3) (Scheme 8).
Scheme 8.
DFT calculations were carried out by the PCꢀGamess (Firefly) program
using B3LYP functional and 6ꢀ311 (2p,2d) basis set. Optimizations
were performed without constraint, and the nature of the stationary
points was confirmed by calculation of vibrational frequencies.
This evidenced that the doubly reduced derivatives of diꢀoꢀ
quinone 3 exist as quinomethide salts (both oꢀquinone fragꢀ
ments are oneꢀelectron reduced). The products prepared by the
twoꢀelectron reduction of one of the two oꢀquinone fragments
were not stable and disproportionated to an initial diꢀoꢀquinone
(3) and a bisꢀcatecholate derivative (like 5).
3.2. Syntheses
4,4'ꢀ(Ethaneꢀ1,2ꢀdiylidene)bis(2ꢀhydroxyꢀ3,6ꢀdiꢀtertꢀbutylꢀ
3. Experimental Section
3.1. General Considerations
cyclohexaꢀ2,5ꢀdienone) (2): 4,4'ꢀ(ethaneꢀ1,2ꢀdiyl)ꢀbis(3,6ꢀdiꢀtertꢀbuꢀ
tylꢀoꢀbenzoquinone) (QꢀCH2–CH2–Q, 1) (2 g, 4.3 mmol) in toluene
(20 mL) was heated to 70–80 °C for 4 h. The obtained precipitate was
recrystallized from dioxane, filtered off and washed with nꢀhexane.
Crystals of 2 suitable for singleꢀcrystal Xꢀray analysis were collected
after prolonged crystallization from toluene solution. Yield 1.42 g
Starting materials were commercially available (Aldrich, Fluka, Strem)
unless otherwise noted. Triphenyltin hydroxide and triphenylantimony
were of reagent grade. 4,4'ꢀ(Ethaneꢀ1,2ꢀdiyl)ꢀbis(3,6ꢀdiꢀtertꢀbutylꢀoꢀ
benzoquinone) Q–CH2–CH2–Q (1) was prepared according to literaꢀ
ture procedure [5a]. Solvents were purified by standard methods [22].
All manipulations with samples for EPR investigations as well as synꢀ
theses of complexes 4 and 5 were carried out in vacuo.
(71 %). Tm
= 250–251 °C. Elemental analysis: calcd. (%) for
C30H42O4: C, 77.21; H, 9.07; found: C, 77.07; H, 8.93. IR (Nujol), ν =
1591 s (C=O); 3213 s (OH) cm–1. UV/Vis (70 °C, toluene): λ =
494.42 nm (ε = 46200 m–1·cm–1). 1H NMR (200 MHz, CDCl3, 25 °C,
TMS): δ = 1.35, 1.61 (both s, 18H, 2 tBu); 7.68 (s, 2H, methyne
protons of = CH–CH = bridge); 8.15 (s, 2 H, 2 OH); 8.20 (s, 2H, 2
1H NMR spectra were recorded with a Bruker AVANCE DPXꢀ200
spectrometer, by using CDCl3 as solvent and tetramethylsilane as interꢀ
nal standard. IR spectra were recorded with a FSN 1201 Fourier specꢀ
trometer. UV/Vis spectra were taken with a Perkin–Elmer lambda 25
spectrometer. Xꢀband EPR spectra were recorded with a “Bruker ER
200 DꢀSRC” spectrometer with thermostat ER 4111 T. The standard
C6H1). 13C NMR (50 MHz, CDCl3, 25 °C, TMS):
δ = 28.9,
36.1[C(CH3)3, C'(C'H3)3]; 32.9 [C(13), C(14), C(15)]; 34.9 [C(9),
C(10), C(11)]; 127.0 [C(7)]; 130.4 [C(5)]; 136.1 [C(4)]; 142.7 [C(2)];
148.4 [C(6)]; 180.1 [C(1)=O(1)].
for g factor was DPPH (g = 2.0037). The C, H analysis of compounds 4,4'ꢀ(Etheneꢀ1,2ꢀdiyl)bis(3,6ꢀdiꢀtertꢀbutylꢀoꢀbenzoquinone)
(Q–
was performed with an Euro EA 3000 elemental analyzer. CH=CH–Q, 3): A solution of K3[Fe(CN)6] (1 g) and KOH (3 g) in
Z. Anorg. Allg. Chem. 2009, 2563–2571
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wileyꢀvch.de
2569

A. I. Poddel’sky et al.
ARTICLE
Table 4. Summary of crystal and refinement data.
2
3
5·toluene
Formula
C30H42O4
466.64
C45H60O6
696.93
C73H78O4Sb2
1262.91
100(2)
Formula weight
Temperature /K
100(2)
100(2)
Wavelength /Å
0.71073
Monoclinic
P21/n
0.71073
Orthorhombic
Pbca
0.71073
Triclinic
Crystal system
¯
P1
Space group
Unit cell dimensions
a /Å
10.124(2)
12.0726(9)
20.1445(14)
32.163(2)
11.0695(12)
11.3986(12)
13.6607(15)
103.388(2)
113.273(2)
90.681(2)
1530.0(3)
1
b /Å
10.856(3)
c /Å
11.705(3)
α /°
90
90
β /°
92.958(5)
90
γ /°
90
90
Volume /Å3
1284.7(5)
7822(1)
Z
2
8
Calculated density /Mg·m–3
Absorption coefficient /mm–1
F(000)
1.206
1.184
1.362
0.078
0.077
0.932
508
3024
642
Crystal size /mm
Theta range for data collection
Limiting indices
0.30 × 0.25 × 0.08
2.01 to 20.16
–9 ≤ h ≤ 9
–10 ≤ k ≤ 10
–11 ≤ l ≤ 11
5704 / 1192 [R(int) = 0.0396]
1035
0.20 × 0.15 × 0.08
2.02 to 29.02
–16 ≤ h ≤ 16
–27 ≤ k ≤ 27
–43 ≤ l ≤ 43
78056 / 10388 [R(int) = 0.0519]
8355
0.16 × 0.16 × 0.16
1.85 to 29.07
–14 ≤ h ≤ 14
–15 ≤ k ≤ 11
–18 ≤ l ≤ 15
Reflections collected / unique
Reflections with I > 2σ(I)
Completeness to theta
11381 / 7923 [R(int) = 0.0155]
7414
θ = 20.16, 96.8 %
0.9938 and 0.9770
Fullꢀmatrix leastꢀsquares on F2
1192 / 0 / 162
1.071
R1 = 0.0754,
wR2 = 0.2032
R1 = 0.0814,
wR2 = 0.2079
0.397 / –0.238
θ = 29.02, 99.6 %
0.9939 and 0.9848
Fullꢀmatrix leastꢀsquares on F2
10388 / 0 / 700
1.100
R1 = 0.0717,
wR2 = 0.1631
R1 = 0.0886,
wR2 = 0.1722
0.640 / –0.242
θ = 29.07, 96.7 %
0.8653 and 0.8653
Fullꢀmatrix leastꢀsquares on F2
7923 / 19 / 510
1.098
Max. and min. transmission
Refinement method
Data / restraints / parameters
Goodnessꢀofꢀfit on F2
Final R indices [I > 2σ(I)]
R1 = 0.0309,
wR2 = 0.0755
R indices (all data)
R1 = 0.0337,
wR2 = 0.0771
Largest diff. peak / hole /e·A–3
1.228 / –0.511
water (200 mL) was added to a hot solution of 2 (1 g, 2.2 mmol) in λ1 = 471.67 nm, λ2 = 764.87 nm. 1H NMR (200 MHz, CDCl3, 25 °C,
toluene (500 mL). The reaction mixture was stirred until the red color TMS): δ = 1.31, 1.61 (both s, 18H, 2 tBu); 7.61 (s, 2H, methyne
disappeared. Toluene was reduced to a volume of 100 mL at atmosꢀ protons of –CH=CH– bridge); 7.43–7.49, 7.75–7.79 (m, 30 H, 6 C6H5
pheric pressure and dark redꢀbrown crystals of 3 suitable for Xꢀray of 2 SnPh3); 8.20 (s, 2H, 2 C6H1).
diffraction were obtained after slow cooling of the solution. Yield
Triphenylantimony(V) bisꢀcatecholate (5): 1. A solution of triphenꢀ
0.92 g (92 %). Tm = 256–257 °C. Elemental analysis: calcd. (%) for
ylstibine (0.155 g, 0.44 mmol) in toluene (20 mL) was added to a soluꢀ
C30H40O4: C, 77.55; H, 8.68; found: C, 77.27; H, 8.31. IR (Nujol): ν =
tion of diꢀoꢀquinone 3 (0.1 g, 0.22 mmol) in toluene (50 mL). After
1 h, the reaction was finished and the solution color turned from greenꢀ
brown to deepꢀyellow. Crystals of 5·toluene suitable for Xꢀray diffracꢀ
tion were obtained after solvent evaporation in vacuo. Yield 0.224 g
1655 s. (C=O), 1685 s. (C=O) cm–1. UV/Vis (50 °C, toluene): λ =
423.25 nm (ε = 14384 m–1·cm–1). 1H NMR (200 MHz, CDCl3, 25 °C,
TMS): δ = 1.27, 1.41 (both s, 18H, 2 tBu); 6.95 (s, 2H, methyne
protons of –CH=CH– bridge); 7.28 (s, 2H, 2 C6H1). 13C NMR
(81 %). Tm = 210–211 °C (decomp.). Elemental analysis: calcd. (%)
(50 MHz, CDCl3, 25 °C, TMS):
δ = 29.00, 31.58 [C(CH3)3,
for C66H70O4Sb2·C7H8: C, 69.43; H, 6.22; Sb, 19.28; found: C, 69.02;
H, 6.33; Sb, 20.18. IR (Nujol): ν = 693 s, 718 s (Ph); 1256 s, 1306 s
(C–O) cm–1. 1H NMR (200 MHz, CDCl3, 25 °C, TMS): δ = 1.44, 1.59
(both s, 18H, 2 tBu); 2.36 (s, 3 H,CH3 of toluene); 6.76 (s, 2H, 2
C6H1); 6.98 (s, 2H, methyne protons of –CH=CH– bridge); 7.15–7.26
(m, 5 H, Ph of toluene); 7.44–7.49, 7.75–7.79 (m., 30 H, 6 C6H5 of 2
SbPh3).
C'(C'H3)3]; 35.09 [C(20), C(21), C(22)]; 36.67 [C(16), C(17), C(18)];
133.19 [C(7)]; 137.28 [C(5)]; 140.38 [C(4)]; 148.66 [C(3)]; 148.99
[C(6)]; 182.79, 186.22 [C=O, C'=O']. DEPT (50 MHz, CDCl3, 25 °C,
TMS): δ = 29.00, 31.58 [C(CH3)3, C'(C'H3)3]; 137.28 [C(5)H and
C(10)H]; 133.19 [C(7)H and C(8)H].
Triphenyltin(IV) pꢀquinomethideꢀphenolate (4): A solution of 2
(0.042 g, 0.09 mmol) in THF (50 mL) was added to a sample of 2. A solution of triphenylstibine (0.078 g, 0.22 mmol) in toluene
Ph3SnOH (0.066 g, 0.18 mmol). The color of the solution turned darkꢀ (10 mL) was added to a solution of diꢀoꢀquinone (3) (0.100 g,
violet. After solvent change to nꢀhexane, 4 precipitated as microcrysꢀ 0.22 mmol) in toluene (50 mL), which caused brightening of the soluꢀ
talline powder. It was filtered, washed with nꢀhexane and dried in tion. Upon evaporation of the solvent in vacuo, first the crystals of
vacuo. Yield 0.078 g (75 %). Elemental analysis: calcd. (%) for initial diꢀoꢀquinone (3) precipitated followed by the crystals of comꢀ
C66H70O4Sn2: C, 68.04; H, 6.01; Sn, 20.45; found: C, 68.23; H, 6.22; plex 5 (0.058 g, yield 21 %) and afterwards an inseparable mixture of
Sn, 19.74. IR (Nujol): ν = 1462 (C–O) cm–1. UV/Vis (50 °C, THF): 3 and 5 was formed.
2570
www.zaac.wileyꢀvch.de
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 2563–2571

BisꢀoꢀBenzoquinoid Ligands with Ethylene Bridge and Their Metal Complexes
Organomet. Chem. USSR 1991, 4, 454–460; b) A. V. Piskunov,
V. K. Cherkasov, N. O. Druzhkov, G. A. Abakumov, V. N. Ikorꢀ
skii, Russ. Chem. Bull. 2005, 54, 1627–1631.
Crystallographic data have been deposited with the Cambridge Crystalꢀ
lographic Data Centre, CCDC No. CCDCꢀ732316 for 2, CCDCꢀ
732317 for 3 and CCDCꢀ732318 for 5·toluene. Copies of this data may
be obtained free of charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: +44ꢀ1223ꢀ336033; EꢀMail: deꢀ
posit@ccdc.cam.ac.uk).
[6] A. L. Spek, PLATON, A Multipurpose Crystallographic Tool,
Utrecht University 2000.
[7] Y. J. AbulꢀHajj, K. T. Tabakovic, W. H. Ojala, W. B. Gleason, J.
Am. Chem. Soc. 1995, 117, 5600.
[8] D. R. Lide, CRC Handbook of Chemistry and Physics,84th Ediꢀ
tion, CRC Press, 2003–2004.
Acknowledgement
[9] S. S. Batsanov, Russ. J. Inorg. Chem. 1991, 36, 3015.
[10] Yu. V. Zefirov, P. M. Zorky, Russ. Chem. Rev. 1995, 64, 415–428.
[11] G. A. Abakumov, V. K. Cherkasov, T. N. Kocherova, N. O.
Druzhkov, Yu. A. Kurskii, M. P. Bubnov, G. K. Fukin, L. G. Abꢀ
akumova, Russ. Chem. Bull. 2007, 56, 1849–1856.
We are grateful to the Russian Foundation for Basic Research (grants
07ꢀ03ꢀ00819ꢀa, 07ꢀ03ꢀ00711ꢀa and 09ꢀ03ꢀ97034ꢀr_povolzh'e_a), Rus
sian President Grants (grants NShꢀ4182.2008.3, 1396.2008.3, MKꢀ
1286.2009.3), Russian Science Support Foundation (A.I. Poddel'sky)
for financial support of this work.
[12] H. Weiner, R. G. Finke, J. Am. Chem. Soc. 1999, 121, 9831.
[13] A. A. Granovsky, PC GAMESS/Firefly version 7.1.C, www http://
classic.chem.msu.su/gran/gamess/index.html.
[14] R. F. W. Bader, Atoms in Molecules A Quantum Theory, Oxford
University Press, Oxford, 1990.
References
[15] T. A. Keith, AIMAll (Version 08.11.06), 2008.
[16] E. Espinosa, E. Molins, C. Lecomte, Chem. Phys. Letters 1998,
285, 170–173.
[1] a) O. Kahn, Molecular Magnetism, VCH, New York, 1993; b) K.
Itoh, M. Kinoshita, Molecular Magnetism, New Magnetic Materi
als, Gordon, Breach, Amsterdam, 2000; c) J. S. Miller, M.
Drillon, Magnetism: Molecules to Materials II: Molecule Based
Materials, WileyꢀVCH, New York, 2001.
[2] a) C. G. Pierpont, Coord. Chem. Rev. 2001, 219–221, 415–433;
b) C. G. Pierpont, Coord. Chem. Rev. 2001, 216–217, 99–125;
c) P. Zanello, M. Corsini, Coord. Chem. Rev. 2006, 250, 2000–
2022; d) O. Sato, J. Tao, Y.ꢀZ. Zhang, Angew. Chem. Int. Ed.
2007, 46, 2152–2187; e) A. I. Poddel’sky, V. K. Cherkasov, G. A.
Abakumov, Coord. Chem. Rev. 2009, 253, 291–324; f) A.
Vlček Jr., Coord. Chem. Rev. 2002, 230, 225–242; g) A. Mederos,
S. Dominguez, R. HernandezꢀMolina, J. Sanchiz, F. Brito, Coord.
Chem. Rev. 1999, 193–195, 913–939.
[3] a) D. A. Shultz, Comments Inorg. Chem. 2002, 23, 1–21; b) D. A.
Shultz, Polyhedron 2001, 20, 1627–1631; c) G. A. Abakumov,
V. I. Nevodchikov, V. A. Kuropatov, B. C. Noll, C. G. Pierpont,
Inorg. Chem. 1998, 37, 6117–6119; d) G. A. Abakumov, V. K.
Cherkasov, V. I. Nevodchikov, V. A. Kuropatov, G. T. Yee, C. G.
Pierpont, Inorg. Chem. 2001, 40, 2434–2436; e) C. G. Pierpont,
T. M. Buchanan, Coord. Chem. Rev. 1981, 38, 45–87; f) C. G.
Pierpont, Coord. Chem. Rev. 2001, 219–221, 415–433.
[17] a) G. A. Abakumov, V. K. Cherkasov, T. N. Kocherova, N. O.
Druzhkov, Y. A. Kursky, G. K. Fukin, L. G. Abakumova, Synth.
Commun. 2006, 36, 3241–3247; b) G. A. Abakumov, V. K.
Cherkasov, T. N. Kocherova, N. O. Druzhkov, Y. A. Kursky,
L. G. Abakumova, Russ. Chem. Bull. 2006, 55, 1195–1199;
[18] a) V. K. Cherkasov, E. V. Grunova, A. I. Poddel’sky, G. K. Fukin,
Yu. A. Kurskii, L. G. Abakumova, G. A. Abakumov, J. Orga
nomet. Chem. 2005, 690, 1273–1281; b) G. A. Abakumov, A. I.
Poddel’sky, E. V. Grunova, V. K. Cherkasov, G. K. Fukin, Yu. A.
Kurskii, L. G. Abakumova, Angew. Chem. Int. Ed. 2005, 44,
2767–2771 c) V. K. Cherkasov, G. A. Abakumov, E. V. Grunova,
A. I. Poddel’sky, G. K. Fukin, E. V. Baranov, Yu. A. Kurskii,
L. G. Abakumova, Chem. Eur. J. 2006, 12, 3916–3927.
[19] a) M. Hall, D. B. Sowerby, J. Am. Chem. Soc. 1980, 102, 628–
632; b) R. R. Holmes, R. O. Day, V. Chandrasekhar, J. M.
Holmes, Inorg. Chem. 1987, 26, 157–163; c) Z. Tian, D. G. Tuck,
J. Chem. Soc., Dalton Trans. 1993, 1381–1385; d) G. K. Fukin,
L. N. Zakharov, G. A. Domrachev, A. U. Fedorov, S. N. Zaburꢀ
dyaeva, V. A. Dodonov, Russ. Chem. Bull. 1999, 48, 1744–1753;
e) M. N. Gibbons, M. J. Begley, A. J. Blake, D. B. Sowerby, J.
Chem. Soc., Dalton Trans. 1997, 2419–2425.
[4] a) W. Baker, J. Chem. Soc. 1934, 1678–1681; b) L. Horner, K.ꢀ
H. Weber, Chem. Ber. 1967, 100, 2842–2853; c) D. A. Shultz,
A. K. Boal, G. T. Farmer, J. Org. Chem. 1998, 63, 9462–9469;
d) D. A. Shultz, H. Lee Jr., R. M. Fiko, Tetrahedron 1999, 55,
12079–12086; e) G. A. Abakumov, V. I. Nevodchikov, N. O.
Druzhkov, L. N. Zakharov, L. G. Abakumova, Yu. A. Kurskii,
V. K. Cherkasov, Russ. Chem. Bull. 1997, 46, 771–775; f) G. A.
Abakumov, V. K. Cherkasov, V. I. Nevodchikov, N. O. Druzhkov,
V. A. Kuropatov, Russ. Chem. Bull. 1998, 47, 875–878; g) A.
Caneschi, A. Dei, C. P. Mussari, D. A. Shultz, L. Sorace, K. E.
Vostrikova, Inorg. Chem. 2002, 41, 1086–1092.
[20] J. Emsley, The Elements, Clarendon Press, Oxford, 1991.
[21] M. Nishio, CrystEngComm 2004, 6, 130–158.
[22] D. D. Perrin, W. L. F. Armarego, D. R. Perrin, Purification of
Laboratory Chemicals, Pergamon, Oxford, 1980.
[23] Sheldrick G. M. SHELXTL v. 6.12, Structure Determination Softꢀ
ware Suite, Bruker AXS, Madison, Wisconsin, USA, 2000.
[24] Sheldrick G. M. SADABS v.2.01, Bruker/Siemens Area Detector
Absorption Correction Program, Bruker AXS, Madison, Wisconꢀ
sin, USA, 1998.
[5] a) G. A. Abakumov, V. K. Cherkasov, L. G. Abakumova, N. O.
Druzhkov, V. I. Nevodchikov, Yu. A. Kurskii, N. P. Makarenko,
Received: May 25, 2009
Published Online: September 25, 2009
Z. Anorg. Allg. Chem. 2009, 2563–2571
© 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wileyꢀvch.de
2571