Structure and properties of ionic fullerene complex Co+(dppe) 2·(C60-)·(C6H 4Cl2)2: Distortion of the ordered fullerene cage of C60- radical anions

Article abstract of DOI:10.1039/c1dt10039d

New ionic complex {Co⁺(dppe)₂}·(C ₆₀^-)·(C₆H₄Cl ₂)₂ (1) was obtained by the reduction of a Co(dppe)Br ₂ and C₆₀ mixture by TDAE in o-dichlorobenzene followed by precipitation of crystals by hexane. Optical and EPR spectra of 1 indicated the formation of C₆₀^- radical anions and diamagnetic Co ⁺(dppe)₂ cations. The structure of 1 solved at 100(2) K involves chains of C₆₀^- arranged along the lattice a-axis with a center-to-center distance of 10.271 A. The chains are separated by bulky Co⁺(dppe)₂ cations and solvent molecules. All components of 1 are well ordered allowing the distortion of the C ₆₀^- radical anion to be analyzed. An elongation of the C₆₀^- sphere by 0.0254(2) was found. It is essentially smaller than those in the salts (Cp*₂Ni⁺) ·(C₆₀^-)·CS₂ and (PPN ⁺)₂·(C₆₀^2-) with greater distortion of the fullerene cage. The calculation of the electronic structure of fullerene by the extended Hueckel method showed slight splitting of the C₆₀ LUMO, due to the distortion, by three levels. Two levels are located 180 and 710 cm^-1 higher than the ground level. The averaged 6-6 and 5-6 bonds in C₆₀^- with lengths of 1.397(2) and 1.449(2) A are close to those determined for the C₆₀ ^2- dianions in (PPN⁺)₂·(C ₆₀^2-), but are slightly longer and shorter, respectively, than the length of these bonds in neutral C₆₀.

Full text of DOI:10.1039/c1dt10039d

View Online / Journal Homepage / Table of Contents for this issue
Dynamic Article Links
Dalton
Transactions
Cite this: Dalton Trans., 2011, 40, 4453
www.rsc.org/dalton
PAPER
Structure and properties of ionic fullerene complex
∑
Co+(dppe)2·(C60 -)·(C6H4Cl2)2: distortion of the ordered fullerene cage of
∑
C60 - radical anions†
Dmitri V. Konarev,*a Alexey V. Kuz´min,b Sergey V. Simonov,b Salavat S. Khasanov,b Evgeniya I. Yudanovaa and
Rimma N. Lyubovskayaa
Received 10th January 2011, Accepted 16th February 2011
DOI: 10.1039/c1dt10039d
∑
New ionic complex {Co+(dppe)2}·(C60 -)·(C6H4Cl2)2 (1) was obtained by the reduction of a Co(dppe)Br2
and C60 mixture by TDAE in o-dichlorobenzene followed by precipitation of crystals by hexane. Optical
∑
-
and EPR spectra of 1 indicated the formation of C60 radical anions and diamagnetic Co+(dppe)2
∑
-
cations. The structure of 1 solved at 100(2) K involves chains of C60 arranged along the lattice a-axis
+
˚
with a center-to-center distance of 10.271 A. The chains are separated by bulky Co (dppe)2 cations and
∑
-
solvent molecules. All components of 1 are well ordered allowing the distortion of the C60 radical
∑
-
anion to be analyzed. An elongation of the C60 sphere by 0.0254(2) was found. It is essentially smaller
∑
than those in the salts (Cp*2Ni+)·(C60 -)·CS2 and (PPN+)2·(C602-) with greater distortion of the fullerene
cage. The calculation of the electronic structure of fullerene by the extended Hu¨ckel method showed
slight splitting of the C60 LUMO, due to the distortion, by three levels. Two levels are located 180 and
∑
710 cm-1 higher than the ground level. The averaged 6–6 and 5–6 bonds in C60 with lengths of 1.397(2)
-
and 1.449(2) A are close to those determined for the C60 dianions in (PPN+)2·(C602-), but are slightly
2-
˚
longer and shorter, respectively, than the length of these bonds in neutral C60.
salt with a triclinic unit cell, showed a strong enough deviation
Introduction
from the fullerene cage Ih symmetry (the difference between the
Ionic fullerene C60 complexes show a variety of promising physical
properties such as metallic conductivity, superconductivity and
ferromagnetism.1–4 Great interest is directed to the intrinsic
˚
longest and the shortest diameter of C60 was 0.086 A) allowing the
authors to conclude on the presence of an intrinsic Jahn–Teller
effect in the C60 dianions.7 Smaller but noticeable distortions
2-
n-
structural and electronic properties of discrete fullerene C60
˚
of the fullerene cage (from 0.060 to 0.075 A) were observed
anions.5,6 The Jahn–Teller theorem predicts distortion of the C60
cage from icosahedral symmetry when additional electrons are
added to the t1u LUMO orbital of C60 to remove its degeneracy. The
presence or absence of such distortion in the fullerene anions are of
particular interest since degeneracy strongly affects the electronic
structure of fullerene and to a great extent defines such phenomena
as superconductivity and ferromagnetism.
in the [M(NH3)62+]·(C602-)·(NH3)3 salts (M = Ni, Mn, and Cd)
with triclinic lattice8,9 and in the (Cp*2Co+)2·(C602-)·(C6H4Cl2,
C6H5CN)2 complex with monoclinic lattice10 However, the study
of the crystal structure of {(Ba2+)·(NH3)7}·(C602-)·NH3 with higher
trigonal lattice symmetry showed that the cage of the C602- dianion
11
˚
is essentially less distorted (0.014 A). Based on this observation
2-
it was concluded that strong or moderate distortion of the C60
Fullerene C60 is nearly a spherical molecule and fullerene
anions are disordered in most ionic complexes and salts. Precise
geometry of ordered fullerene anions was determined in a few
compounds only.7–11 These are mainly compounds containing
cage observed in previously studied compounds may be a result
2-
of a low-symmetry, triclinic environment of C60 rather than the
11
intrinsic Jahn–Teller effect.11 Indeed, the distortion of 0.014 A
˚
is even smaller than that of the neutral fullerene cage in C60
2-
2-
C60 dianions. The first crystal structure of the (PPN+)2·(C60
)
12
˚
(0.025 A) which is not subject to the Jahn–Teller effect.
The strongest distortion of the fullerene cage from Ih sym-
∑
-
metry was found for well-ordered C60 radical anions in the
aInstitute of Problems of Chemical Physics RAS, Chernogolovka, Moscow
region, 142432, Russia. E-mail: konarev@icp.ac.ru; Fax: +7-49652-21852
+
-
13
˚
(Cp*2Ni )·(C60· )·CS2 complex with monoclinic lattice (0.098 A).
In this compound a pentamethylcyclopentadienyl ring of Cp*2Ni+
is located exactly over the C60 pentagon and multiple short van
bInstitute of Solid State Physics RAS, Chernogolovka, Moscow region,
142432, Russia
∑
-
† Electronic supplementary information (ESI) available: IR, UV-Vis-NIR
and EPR spectra of complex 1 and starting compounds. CCDC reference
number 805414. For ESI and crystallographic data in CIF or other
electronic format see DOI: 10.1039/c1dt10039d
der Waals C . . . C contacts are formed between them. Therefore,
∑
-
strong p–p interactions of C60 with closely located Cp*2Ni+
cations can additionally contribute to the ellipsoidal distortion
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4453–4458 | 4453
©

View Online
∑
of C60 -. Both antiferromagnetic and ferromagnetic phases of
room temperature (supporting information†). Such signals are
(TDAE∑+)·(C60 -) have a monoclinic lattice and contain ordered
generally observed in the complexes and salts containing C60
radical anions.4,5 Integral intensity of this signal corresponds to
the contribution of about one S = 1/2 spin per formula unit.
∑
∑
-
∑
∑
-
-
C60 radical anions which show a smaller distortion of the C60
14,15
˚
cage (0.02–0.04 A).
∑
In this work we obtained the new ionic complex
In the background of the broad signal from C60 -, a very weak
∑
of fullerene, {Co+(dppe)2}·(C60 -)·(C6H4Cl2)2 where dppe is
narrow signal with approximate g-factor of about 2.0000 can also
be resolved. This signal originates from about 0.3% of spins of
total amount of C60 and can be attributed to defects.
bis(diphenylposphinio)ethane (1), as single crystals. The analysis
of the EPR-, IR- and optical spectra of 1 showed the formation of
∑
the C60 radical anions and the diamagnetic Co+(dppe)2 cations.
Starting compound Co(dppe)Br2, with paramagnetic Co2+ ions,
manifests a broad intense EPR signal with g-factor = 2.0357 and
DH = 15.5 mT. It is expected that cobalt ions in 3+ and 1+ charged
states with d6 and d8 electronic configurations, respectively, should
be diamagnetic and EPR silent. Indeed, the EPR spectrum of 1
-
The structure of 1 determined at 100(2) K contains completely
ordered C60 radical anions for which the distortion from Ih
symmetry is discussed.
∑
-
∑
shows no additional signals to that from C60 -. Thus, the EPR data
Results and discussion
justify the reduction of paramagnetic and EPR active Co2+ to the
EPR silent Co+. Electroneutrality of the complex also justifies the
formation of monocationic Co+(dppe)2 species since the complex
involves cations and fullerene anions at a 1 : 1 ratio and the charged
state of C60 was estimated to be 1-.
a. Synthesis
Tetrakis(dimethylamino)ethylene (TDAE) reduces C60 in o-
dichlorobenzene (C6H4Cl2) to the radical anion state. How-
ever, the diffusion of hexane into C6H4Cl2 solution containing
∑
∑
-
TDAE + and C60 ions does not afford the crystals of the
ionic complex. On the contrary, in these conditions fullerene
C70 forms two phases: (TDAE∑+)·(C70-)·(C6H4Cl2)·(C6H14)0.5 and
(TDAE∑+)·(C70-)·(C6H4Cl2).16 When the mixture of Co(dppe)Br2
and C60 is reduced by an excess of TDAE, all components dissolve
to produce a violet-red solution from which well-shaped black
c. Crystal structure of the complex
The crystal structure of 1 was studied at 100(2) K. It has
∑
+
-
a monoclinic unit cell with well-ordered Co(dppe)2 and C60
ions and solvent C6H4Cl2 molecules (R-factor is 3.28%). The
Co+(dppe)2 cation with the 1+ charged four-coordinated cobalt
atom was generated in solution electrochemically at -0.7
∑
elongated parallelepipeds of {Co+(dppe)2}·(C60 -)·(C6H4Cl2)2 (1)
2+
are crystalized by diffusion of hexane. TDAE reduces both C60
V starting from {Co(dppe)2(CH3CN)} which loses CH3CN
∑
-
to C60 and Co2+ to Co+. Previously it was shown that Co2+ in
{Co(dppe)2(CH3CN)} can be reduced electrochemically to Co+
at -0.7 V.17 This is possible for TDAE as well since it has a
more negative first oxidation potential (E+/0 = -0.75 V).18 Further
reduction of Co+ to Co0 realized at -1.56 V17 cannot occur in these
conditions.
molecules during the reduction.17 The structure of individual
Co(dppe)2 cations was unknown. However, some L2Co+(dppe)2
+
cations with six-coordinated cobalt atoms were structurally
characterized: {H2Co+(dppe)2}, {HCo+(dppe)2(CH3CN)} and
{O2Co+(dppe)2}.17,23
Ni(dppp)Cl2 (dppp is bis(diphenylposphino)propane) and C60
2
after reduction by sodium fluorenone forms a Ni(dppp)·(h -C60)
2
complex where zero valent nickel coordinates to C60 by the h -type.
˚
In these coordination units, the Ni–C(C60) bonds of 1.950(2) A
length are essentially shorter than the Ni–P bonds (2.152(2) and
19
2.155(2) A). It is interesting that the Co(dppe)+ unit does not
˚
∑
-
2
add to C60 to form a coordinated Co(dppe)·(h -C60) complex.
Instead of that, the Co+(dppe)2 cations are formed in solution and
∑
-
co-crystalize with non-bonded C60
.
b. Charged state of C60 and diamagnetism of Co+(dppe)2
The spectra of 1 in the IR- and UV-visible-NIR ranges are shown
in supporting information.† IR active modes of C60 manifest
absorption bands at 533 (coincides with the band of Co+(dppe)2),
576, 1180, and 1390 cm-1. The F1u(4) mode which is most sensitive
to the charged state of C60 is shifted from 1429 cm-1 in the neutral
state to 1396–1388 cm-1 in the radical anion state.20–22 The position
of this mode in the spectrum of 1 at 1390 cm-1 indicates the
∑
-
formation of the C60 radical anions. The spectrum of 1 with two
bands in the NIR range at 930 and 1090 nm is also characteristic
∑
-
4,5
of C60
.
The EPR spectrum provides further evidence of the ionic ground
state of 1. The compound manifests a broad intense EPR signal
with a g-factor of 1.9986 and a linewidth (DH) of 4.57 mT at
Fig. 1 The structure of Co+(dppe)2 cation viewed on upper (a) and along
(b) one PCoP plane.
4454 | Dalton Trans., 2011, 40, 4453–4458
This journal is
The Royal Society of Chemistry 2011
©

View Online
Fig. 2 The crystal structure of 1 viewed along the lattice c- (a) and b-axes (b).
Since the cobalt atom has d8 configuration in Co+(dppe)2,
square-planar geometry for this ion is expected. Nevertheless, the
P4Co fragment is not planar (Fig. 1). The angle between two P2Co
planes is 21.82(2)◦. Such geometry is different from the tetrahedral
geometry of neutral Co0(dppp)2 and anionic Co-(dppe)2.24,25 The
with two C6H4Cl2 molecules. Multiple shortened van der Waals
∑
-
H(Co+(dppe)2, C6H4Cl2) . . . C(C60 ) contacts in the 2.84–2.89 A
˚
∑
-
range and several C(phenyl group of Co+(dppe)2) . . . C(C60
)
∑
-
˚
contacts of 3.20 A length provide complete ordering of C60 in
this complex.
Co–P bond length in Co+(dppe)2 is in the 2.182–2.204(2) A
˚
range. The ability of CoIIporphyrins to form coordination Co–
d. Analysis of the fullerene distortion in 1
∑
-
C bonds with C60 is known.26–29 In the case of Co+(dppe)2, such
∑
coordination is not possible since a close approach of bulky C60 - to
∑
-
Ordering of C60 provides an opportunity to study the distortion
Co+ is sterically blocked. Moreover, the shortest distances between
∑
∑
-
of the C60 - radical anions in 1. Labels of the carbon atoms in C60
∑
-
Co+ and a carbon atom of C60 exceeds 8 A showing a minimal
˚
are shown in Fig. 3a and the distances of the carbon atoms from
the center of fullerene are presented in Fig. 3b. These distances
∑
-
effect of the cations on the geometry of C60
The C60 radical anions form chains arranged along the lattice
.
∑
-
˚
vary in a narrow range from 3.537(2) to 3.555(2) A with the mean
˚
a-axis (Fig. 2a shows fragments of the two chains). The center-to-
center distance of 10.271 A between the fullerenes in the chain is
value of 3.545(2) A. All twelve carbon atoms (C301, C302, C306,
˚
C307, C311, C312 and their symmetrically located equivalents
shown by red circles in Fig. 3a) which have the longest distance
from the center belong to two oppositely located hexagons. This
˚
longer than the van der Waals diameter of C60 (10.18 A) and
no van der Waals C . . . C contacts are formed between them.
Fullerene chains are separated by bulky Co+(dppe)2 cations and
solvent C6H4Cl2 molecules. As a result, the shortest center-to-
center distance between fullerenes from different chains is quite
∑
-
indicates the elongation of the C60 sphere along the axis passed
through the centers of two 6–6 bonds (these bonds involved C311
and C312 atoms and their symmetrically located equivalents).
This axis forms an angle of 41.5◦ with the lattice a-axis along
∑
-
˚
long (13.6 A). Each C60 is surrounded by the phenyl groups
of six Co+(dppe)2 cations and forms van der Waals contacts
∑
-
which linear C60 chains are formed (Fig. 2a). The distances
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4453–4458 | 4455
©

View Online
Teller effect in neutral C60, it can be concluded that the effect
∑
-
observed in C60 is rather small.
The electronic structure of fullerene in 1 was calculated using
the extended Hu¨ckel method based on the crystal structure.30
This method provides reasonable values for the energy levels of
molecular orbitals in C60 since the calculated HOMO–LUMO
gap of 1.50 eV is close to the experimentally31 and theoretically32
determined HOMO–LUMO gap in C60. It is known that the
LUMO of C60 with ideal Ih symmetry consists of three degenerated
molecular orbitals (labeled as 121, 122 and 123). The distortion of
∑
-
C60 results in a small splitting of the LUMO. The 121 molecular
orbital is lowest in energy and is occupied by one electron. It is
distributed over the belt coming through two oppositely located
hexagons with the maximal distance in the fullerene cage as
shown in Fig. 4. The 122 molecular orbital is located 180 cm-1
(260 K) higher and should be almost empty at 100(2) K. It is
also distributed over the belt coming through two oppositely
located hexagons with the maximal distance (Fig. 4). It should
be noted that the splitting of 180 cm-1 is noticeably smaller than
the experimentally determined gap of 730 cm-1 between singlet and
triplet states for the C602- dianions in (Cp*2Co+)2·(C602-)·(C6H4Cl2,
2-
C6H5CN)2.10 However, the distortion of the C60 dianions in this
complex is also noticeably stronger (the difference between the
10
˚
˚
longest and the shortest diameter of C60 was 0.060 A vs. 0.026 A
in 1). The highest in energy, the empty 123 orbital, is located above
the 121 level by 710 cm-1 (1020 K) and is distributed over the belt
located perpendicular to the long axis of the fullerene ellipsoid
(Fig. 4).
Fig. 4 The direction of the long axis of the fullerene ellipsoid (yellow
arrow) and the distribution of the 121, 122 and highest in energy 123
∑
Fig. 3 Atom labeling in the C60 - radical anion. (a) Red labels mark atoms
∑
molecular orbitals over the C60 -cage calculated by the extended Hu¨ckel
with the longest distances from the center, violet labels mark atoms with
the shortest distances from the center and green labels mark atoms with
mean distances from the center. (b) Distances of the carbon atoms of C60
from the center.
method.
∑
-
∑
-
The 6–6 and 5–6 bond lengths in C60 are within the 1.393(2)–
˚
1.401(2) and 1.446(2)–1.456(2) A range and are averaged at
1.397(2) and 1.449(2) A, respectively. The C602- dianions with max-
˚
imally distorted fullerene cage have close averaged lengths of the
between the midpoints of two oppositely located 6–6 bonds in
+
6–6 and 6–5 bonds of 1.399(2) and 1.446(2) A in (PPN )2·(C602-).7
˚
˚
three orthogonal directions are 6.944, 6.948 and 6.970 A. The
˚
Neutral C60 has slightly shorter 6–6 bonds of 1.391(8) A and longer
latter distance was measured for the midpoints of two oppositely
located 6–6 bonds having maximal distance from the center of
5–6 bonds of 1.455(8) A.33 The direction of the bond length change
˚
at C60 charging is in accordance with the theory which predicts
that the t1u LUMO orbital is antibonding for the 6–6 bonds and
bonding for the 6–5 bonds.34
the fullerene (Fig. 3b). The difference between the longest and the
∑
shortest diameter of C60 is only 0.026 A. The ellipsoid of C60 - was
˚
calculated by the least-squares method in an orthogonal system
using the following equation: (Xnew/3.5522)2 + (Ynew/3.5395)2 +
(Znew/3.5420)2 = 1. The greatest radius was obtained to be
Conclusion
˚
˚
3.5520(1) A and two other radii were 3.5420(1) and 3.5395(1) A.
∑
The difference between the longest and shortest diameter of the
A new ionic fullerene complex {Co+(dppe)2}·(C60 -)·(C6H4Cl2)2 (1)
∑
-
˚
C60 ellipsoid is also 0.0254(2) A, i.e. essentially smaller than those
was obtained. Optical and EPR spectra indicate the formation of
∑
∑
-
in the (Cp*2Ni+)·(C60 -)·CS2 and (PPN+)2·(C602-) salts with strong
C60 radical anions and diamagnetic Co+ (dppe)2 cations whose
∑
-
˚
distortion of the fullerene cage (0.086–0.098 A). The distortion of
molecular structures were analyzed. The C60 cage elongates by
12
˚
˚
fullerene in neutral C60 is 0.025 A only. Since there is no Jahn–
0.0254(2) A. This distortion is essentially smaller than that in
4456 | Dalton Trans., 2011, 40, 4453–4458
This journal is The Royal Society of Chemistry 2011
©

View Online
∑
the (Cp*2Ni+)·(C60 -)·CS2 and (PPN+)2·(C602-) salts and is close to
intensity of the signal from a weighed amount of the complex was
compared with that of the signal from a sample of a,a¢-diphenyl-
b-picrylhydrazid (DPPH) with a known number of spins.
that in neutral C60. The calculation of the electronic structure of
fullerene by the extended Hu¨ckel method showed slight splitting
of the C60 LUMO due to the distortion by 180 and 710 cm-1.
The splitting between occupied 121 and nearly empty 122 orbitals
is smaller than the experimentally determined singlet–triplet
X-Ray crystal structure determination
Crystal data for 1. C124H56Cl4CoP4, Mr = 1870.30 g mol-1, black
parallelepiped, monoclinic, C 2/c, a = 10.2711(5), b = 39.2279(18),
energy gap for the C60 dianions in (Cp*2Co+)2·(C602-)·(C6H4Cl2,
2-
C6H5CN)2.10 The averaged 6–6 and 5–6 bond lengths of 1.397(2)
◦
3
∑
-
˚
˚
˚
c = 20.6979(11) A, b = 100.241(5) , V = 8206.6(7) A , Z = 4, dc =
1.514 g cm-3, m = 0.479 mm-1, F(000) = 3820, T = 100(2) K,
2qmax = 54.2◦, reflections measured 31494, unique reflections 8950,
reflections with I > 2s(I) = 7369, parameters refined 600, restrains
0, R1 = 0.0328, wR2 = 0.0877, GOF= 1.065.
and 1.449(2) A in C60 are close to those determined for the
C60 dianions in (PPN+)2·(C602-) but slightly longer and shorter,
2-
respectively, than the length of these bonds in neutral C60.
Experimental
X-Ray diffraction data for 1 were collected on an Ox-
ford diffraction “Gemini-R” CCD diffractometer with graphite
monochromated Mo-Ka radiation using an Oxford Instrument
Cryojet system. Raw data reduction to F2 was carried out using
CrysAlisPro, Oxford Diffraction Ltd. The structure was solved by
direct method and refined by the full-matrix least-squares method
against F2 using SHELX-97.35 Non-hydrogen atoms were refined
in the anisotropic approximation. Positions of hydrogen atoms
were calculated geometrically. Subsequently, the positions of H
atoms were refined by the “riding” model with Uiso = 1.2Ueq of the
Materials
CoBr2, bis(diphenylposphinio)ethane (dppe) and TDAE were pur-
chased from Aldrich. C60 of 99.9% purity was used from MTR Ltd.
Solvents were purified in argon atmosphere. o-Dichlorobenzene
(C6H4Cl2) was distilled over CaH2 under reduced pressure and
hexane was distilled over Na/benzophenone. The solvents were
degassed and stored in a glove box. All manipulations for the
synthesis of 1 were carried out in a MBraun 150B-G glove box
with controlled atmosphere and the content of H2O and O2 was
less than 1 ppm. The crystals were stored in a glove box and put in
anaerobic conditions in 5 mm quartz tubes for EPR measurements
under argon. KBr pellets for IR and UV-Vis-NIR measurements
were prepared in a glove box.
connected non-hydrogen atom or as ideal CH3 groups with Uiso
=
1.5Ueq.
Acknowledgements
The work was supported by the RFBR grant No 09-02-01514.
Synthesis
For the preparation of Co(dppe)Br2, anhydrous CoBr2 (300 mg,
1.38 mmol) was dissolved in 10 ml of acetonitrile (AN) and an
equimolar amount of dppe was added (547 mg, 1.38 mmol) to this
solution. After 1 h the green crystalline precipitate was filtered,
washed with 5 ml of cold AN and dried in air. Yield was 720 mg
(82%).
The crystals of 1 were obtained by diffusion. C60 (30 mg,
0.035 mmol), Co(dppe)Br2 (43 mg, 0.07 mmol) and an excess of
TDAE (0.5 ml) were dissolved in 14 ml of DCB upon stirring at
60 ◦C for a night to produce violet-red solution. The solution was
cooled down to room temperature, filtered in a 50 ml glass tube of
1.8 cm diameter with a ground glass plug, and 30 ml of hexane was
layered over the solution. Diffusion was carried out for 1 month
to yield the crystals of 1 on the wall of the tube. The solvent was
decanted from the crystals, which were washed with hexane to give
black well-shaped elongated parallelepipeds of 1 up to 0.3 ¥ 0.3 ¥
1 mm3 in size with 50% yield. The composition of the complex
was determined from the X-ray diffraction on a single crystal of
Co(dppe)2·C60·(C6H4Cl2)2 (1). Several single crystals selected from
the synthesis had similar unit cell parameters.
Notes and references
1 M. J. Rosseinsky, J. Mater. Chem., 1995, 5, 1497.
2 B. Gotschy, Fullerene Sci. and Technol., 1996, 4, 677.
3 D. V. Konarev, S. S. Khasanov, A. Otsuka, M. Maesato, G. Saito and
R. N. Lyubovskaya, Angew.Chem. Int. Ed., 2010, 49, 4829.
4 D. V. Konarev and R. N. Lyubovskaya, Russ. Chem. Rev., 1999, 68, 19.
5 C. A. Reed and R. D. Bolskar, Chem. Rev., 2000, 100, 1075.
6 D. V. Konarev, S. S. Khasanov and R. N. Lyubovskaya, Russ. Chem.
Bull., 2007, 56, 371.
7 P. Paul, Z. Xie, R. Bau, P. D. W. Boyd and C. A. Reed, J. Am. Chem.
Soc., 1994, 116, 4145.
8 K. Himmel and M. Jansen, Eur. J. Inorg. Chem., 1998, 1183.
9 K. Himmel and M. Jansen, Chem. Commun., 1998, 1205.
10 D. V. Konarev, S. S. Khasanov, G. Saito, I. I. Vorontsov, A. Otsuka, R.
N. Lyubovskaya and Yu. M. Antipin, Inorg. Chem., 2003, 42, 3706.
11 K. Himmel and M. Jansen, Inorg. Chem., 1998, 37, 3437.
12 H.-B. Bu¨rgi, E. Blanc, D. Schwarzenbach, S. Liu, Y.-J. Lu, M. M.
Kappers and J. A. Ibers, Angew. Chem., Int. Ed. Engl., 1992, 31, 640.
13 W. C. Wan, X. Liu, G. M. Sweeney and W. E. Broderick, J. Am. Chem.
Soc., 1995, 117, 9580.
14 B. Narimbetov, H. Kobayashi, M. Tokumoto, A. Omerzu and D.
Mihailovic, Chem. Commun., 1999, 1511.
15 M. Fujiwara, T. Kambe and K. Oshima, Phys. Rev. B: Condens. Matter
Mater. Phys., 2005, 71, 174424.
16 D. V. Konarev, S. S. Khasanov, S. V. Simonov, E. I. Yudanova and R.
N. Lyubovskaya, CrystEngComm, 2010, 12, 3542.
17 R. Ciancanelli, B. C. Noll, D. L. DuBois and M. Rakowski DuBois, J.
Am. Chem. Soc., 2002, 124, 2984.
18 K. Kuwata and D. H. Geske, J. Am. Chem. Soc., 1964, 86, 2101.
19 D. V. Konarev, S. S. Khasanov, E. I. Yudanova and R. N. Lyubovskaya,
Eur. J. Inorg. Chem., 2011, 816–820.
20 T. Picher, R. Winkler and H. Kuzmany, Phys. Rev. B: Condens. Matter,
1994, 49, 15879.
General
FT-IR spectra were measured in KBr pellets with a Perkin–
Elmer 1000 series spectrometer (400–7800 cm-1). The UV-visible
spectrum was measured in KBr pellet on a Shimadzu-3100
spectrometer in the 600–1500 nm range. The EPR spectrum of
1 was recorded at room temperature with a Radiopan SE/X-2547
spectrometer. For the estimation of a number of spins in 1, integral
21 N. V. Semkin, N. G. Spitsina, S. Krol and A. Graja, Chem. Phys. Lett.,
1996, 256, 616.
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4453–4458 | 4457
©

View Online
22 D. V. Konarev, S. S. Khasanov, G. Saito, A. Otsuka, Y. Yoshida and R.
N. Lyubovskaya, J. Am. Chem. Soc., 2003, 125, 10074.
23 T. Ohishi, K. Kashiwabara, J. Fujita, S. Ohba, T. Ishii and Y. Saito,
Bull. Chem. Soc. Jpn., 1986, 59, 385.
24 Y. Imamura, T. Mizuta, K. Miyoshi, H. Yorimitsu and K. Oshima,
Chem. Lett., 2006, 35, 260.
25 W. W. Brennessel, V. G. Young Jr. and J. E. Ellis, Angew. Chem., Int.
Ed., 2002, 41, 1211.
26 D. V. Konarev, S. S. Khasanov, A. Otsuka, Y. Yoshida, R. N.
Lyubovskaya and G. Saito, Chem.–Eur. J., 2003, 9, 3837.
27 D. V. Konarev, S. S. Khasanov, A. Otsuka, G. Saito and R. N.
Lyubovskaya, Chem.–Eur. J., 2006, 12, 5225.
29 D. V. Konarev, S. S. Khasanov, A. Otsuka, G. Saito and R. N.
Lyubovskaya, Dalton Trans., 2009, 6416.
30 T. Mori, A. Kobayashi, Y. Sasaki, H. Kobayashi, G. Saito and H.
Inokuchi, Bull. Chem. Soc. Jpn., 1984, 57, 627.
31 S. Saito and A. Oshiyama, Phys. Rev. Lett., 1991, 66, 2637.
32 R. W. Lof, M. A. van Veenendaal, B. Koopmans, H. T. Jonkman and
G. A. Sawatzky, Phys. Rev. Lett., 1992, 68, 3924.
33 W. I. F. David, R. M. Ibberson, J. C. Matthewman, K. Prassides, T.
John, S. Dennis, J. P. Hare, H. W. Kroto, R. Taylor and D. R. M.
Walton, Nature, 1991, 353, 147.
34 W. H. Green Jr., S. M. Gorum, G. Fitzgerald, P. W. Fowler, A. Ceuleman
and B. C. Titeca, J. Phys. Chem., 1996, 100, 14892.
28 D. V. Konarev, S. S. Khasanov, G. Saito and R. N. Lyubovskaya, Cryst.
Growth Des., 2009, 9, 1170.
35 G. M. Sheldrick, SHELX97, University of Go¨ttingen, Germany,
1997.
4458 | Dalton Trans., 2011, 40, 4453–4458
This journal is
The Royal Society of Chemistry 2011
©