Syntheses and structures of magnesium, calcium, europium, gallium, and zinc complexes with bis(imino)acenaphthene ligands

Article abstract of DOI:10.1007/s11172-013-0262-3

The reduction of 1,2 bis(trimethylsilylimino)acenaphthene and 1,2-bis{[3,5-bis(trifluoro-methylphenyl)]imino}acenaphthene with metals gave magnesium, calcium, europium, zinc, and gallium complexes containing radicalanion and dianionic ligands of the 1,2-d

Full text of DOI:10.1007/s11172-013-0262-3

Russian Chemical Bulletin, International Edition, Vol. 62, No. 8, pp. 1815—1828, August, 2013
1815
Syntheses and structures of magnesium, calcium, europium, gallium,
and zinc complexes with bis(imino)acenaphthene ligands*
I. L. Fedushkin,a A. A. Skatova,a N. L. Bazyakina,a V. A. Chudakova,a N. M. Khvoinova,a
A. S. Nikipelov,a O. V. Eremenko,a A. V. Piskunov,a G. K. Fukin,a and K. A. Lyssenkob
aG. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences,
49 ul. Tropinina, 603950 Nizhni Novgorod, Russian Federation.
Fax: +7 (831) 462 7497. Eꢀmail: igorfed@iomc.ras.ru
bA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation
The reduction of 1,2ꢀbis(trimethylsilylimino)acenaphthene and 1,2ꢀbis{[3,5ꢀbis(trifluoroꢀ
methylphenyl)]imino}acenaphthene with metals gave magnesium, calcium, europium, zinc,
and gallium complexes containing radicalꢀanion and dianionic ligands of the 1,2ꢀdiiminoꢀ
acenaphthene type. Their structures were studied by 1H NMR, ESR, and/or singleꢀcrystal
Xꢀray analysis. Some chemical transformations of the complexes were carried out.
Key words: magnesium complexes, calcium complexes, europium complexes, zinc comꢀ
plexes, gallium complexes, acenaphtheneꢀ1,2ꢀdiimines.
Acenaphtheneꢀ1,2ꢀdiimines (BIAN) presently attract
attention as ligands1 used in both synthetic organic chemꢀ
istry and catalysis. Transition metal complexes based on
BIAN are highly efficient catalysts for diverse chemical
processes, such as alkyne hydrogenation,2 С—С bond forꢀ
mation,3,4 cycloisomerization,5 and especially polymerꢀ
ization of olefins,6—10 including acrylic monomers.11 We
accumulated a large material on acenaphtheneꢀ1,2ꢀdiꢀ
imine derivatives of nonꢀtransition metals.
The chemistry of metal complexes with 1,2ꢀbis[(2,6ꢀdiꢀ
isopropylphenyl)imino]acenaphthene (dppꢀBIAN) was
developed by us in most detail. Derivatives of alkali12 and
alkalineꢀearth metals13 and 13 Group metals14 were synꢀ
thesized and characterized. Due to unique steric and elecꢀ
tronic properties of dppꢀBIAN, we succeeded to synthesize
and structurally characterize the zinc and gallium derivaꢀ
tives with direct metal—metal bonds: (dppꢀBIAN)Zn—
Zn(dppꢀBIAN), (dppꢀBIAN)Ga—Ga(dppꢀBIAN), and
(dppꢀBIAN)Zn—Ga(dppꢀBIAN).15 The exchange reacꢀ
tions of sodium salts of various acenaphtheneꢀ1,2ꢀdiimines
with GeCl2 gave compounds of divalent germanium with
the dianionic ligand: (dppꢀBIAN)Ge, (dtbꢀBIAN)Ge,
and (dphꢀBIAN)Ge16 and with the radical anion
(dppꢀBIAN)GeCl.17
Alkali metals consequently reduce acenaphtheneꢀ1,2ꢀ
diimines to monoꢀ, diꢀ, triꢀ, and tetraanions,12,18 whereas
the reduction with magnesium and calcium stops at the
stage of the monomeric derivatives with the dianionic
ligand: (dppꢀBIAN)M(L)n (M = Mg, Ca; L = THF,
C5H5N)13 (dtbꢀBIAN)Mg(THF)2, (dphꢀBIAN)M(L)n
(M = Mg, L = DME, n = 2; M = Ca; L = THF, n = 3).19
According to the singleꢀcrystal Xꢀray data, in these comꢀ
plexes the BIAN dianion chelates the metal atom, and the
number of molecules of coordination solvent increases with
an increase in the ion radius of the metal atom. The magꢀ
nesium complex with dppꢀBIAN crystallizes from THF
with three coordinatively bound solvent molecules, and
the calcium complex crystallizes with four solvent moleꢀ
cules. The addition of an equimolar amount of dppꢀBIAN
* Dedicated to blessed memory of the Corresponding Memꢀ
ber of the Russian Academy of Sciences M. Yu. Antipin
(1951—2013).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1815—1828, August, 2013.
1066ꢀ5285/13/6208ꢀ1815 © 2013 Springer Science+Business Media, Inc.

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Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
Fedushkin et al.
to solutions of (dppꢀBIAN)M(THF)n (M = Mg, Ca) in
THF does not give bis(ligand) complexes. However, the
replacement of the solvent by toluene or 1,2ꢀdimethoxyꢀ
ethane induces the formation of paramagnetic bis(ligand)
complexes containing two radicalꢀanion ligands (dppꢀ
BIAN)2М (М = Mg, Ca).20 Unlike the complexes with
(dppꢀBIAN)2–, the magnesium and calcium derivatives
of the dtbꢀBIAN ligand interact with neutral dtbꢀBIAN in
THF to form the paramagnetic bis(ligand) derivatives (dtbꢀ
BIAN)2Mg and (dtbꢀBIAN)2Ca(THF).20
In this work, we report the synthesis, molecular strucꢀ
ture and 1Н NMR and ESR studies of new nonꢀtransition
metal complexes with reduced forms of two rarely used
ligands of the BIAN family, namely, with 1,2ꢀbis(triꢀ
methylsilylimino)acenaphthene (1, tmsꢀBIAN) and 1,2ꢀbisꢀ
{[3,5ꢀbis(trifluoromethylphenyl)]imino}acenaphthene
(2, FꢀBIAN).
dark blue crystals from concentrated THF solutions in 57
and 65% yields, respectively. The synthesized compounds
were identified by IR spectroscopy (3—5) and Н NMR
1
spectroscopy (3 and 4). The molecular structures of
complexes 3—5 were determined by singleꢀcrystal Xꢀray
analysis.
1
The Н NMR spectra of compounds 3 (C6D6) and 4
(THFꢀd8) are poorly informative: they contain signals from
the trimethylsilyl groups exhibiting some upfield shift comꢀ
pared to free tmsꢀBIAN (1). The chemical shifts of
the protons of the Me3Si groups in free diimine 1 are
0.51 ppm,18 and in compounds 3 and 4 they are 0.27 and
0.43 ppm, respectively. For the twoꢀelectron reduction of
diimine 1, the negative charge is mainly localized on the
nitrogen atoms and, hence, the signal from the protons of
the Me3Si groups is shifted upfield. The protons of the
naphthalene moiety of the ligand presented by broadened
signals in the aromatic region also exhibit a slight upfield
shift. In the spectrum of compound 3, one can observe the
signals from the coordinatively bound tetrahydrofuran.
According to the singleꢀcrystal Xꢀray data, unlike comꢀ
pound 3, complex 4 is not a centrosymmetric dimer but
contains coordinatively nonequivalent diimine ligands. In
this case, its should be expected that the signals from two
Results and Discussion
Synthesis and identification of compounds [(tmsꢀBIAN)ꢀ
Mg(THF)]2 (3), [(tmsꢀBIAN)2Сa(THF)]Ca(THF)2 (4),
and [(tmsꢀBIAN)Eu(THF)2]2 (5). The reduction of
tmsꢀBIAN with magnesium, calcium, or europium in
a THF solution affords the corresponding complexes
with the dianionic tmsꢀBIAN ligand. The reaction of
tmsꢀBIAN with metallic magnesium (chips) occurs with
stirring at ambient temperature. The color of the solution
changes from orange to dark blue. After the decantation of
the solution from a metal excess, replacement of the solvent
by toluene, and crystallization, compound [(tmsꢀBIAN)ꢀ
Mg(THF)]2 (3) is isolated in 65% yield as dark blue, alꢀ
most black crystals (Scheme 1). The reactions of calcium
and europium (pieces) with tmsꢀBIAN occur at a noticeꢀ
able rate only on heating (80 С) and cease within 1—2 h.
Compounds [(tmsꢀBIAN)Ca(THF)]Ca(THF)2 (4) and
[(tmsꢀBIAN)Eu(THF)2]Eu(THF)2 (5) were isolated as
1
ligands in the Н NMR spectrum will be nonequivalent.
However, no doubling of the number of signals from the
tmsꢀBIAN fragment compared to the initial compound 1
is observed in the 1Н NMR spectrum in С6D6. Perhaps, in
a THF solution compound 4 exists as a monomer. The IR
spectra of compounds 3—5 contain no bands of stretching
vibration frequencies of the C=N bonds characteristic of
free diimine 1 (1688 and 1669 cm–1), but the intense band
(1303 cm–1) appears corresponding to the C—N bond
vibrations in the dianionic ligands.
Synthesis and identification of compounds [(FꢀBIAN)2ꢀ
Mg(Et2O)]Mg(THF)2 (6) and [(FꢀBIAN)2Ca(THF)2]ꢀ
Ca(THF)2 (7). Compounds 6 and 7 are formed by the
Scheme 1
R = —SiMe3
Conditions: i. Excess Mg, THF. ii. Excess Ca, THF.

Diiminoacenaphthene complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
1817
Scheme 2
Conditions: i. Excess Mg, (1) THF, (2) benzene, (3) ether. ii. Excess Ca, (1) THF, (2) toluene.
Scheme 3
reduction of diimine FꢀBIAN (2) with an excess of the
corresponding activated metal in THF with stirring at amꢀ
bient temperature. The removal of the solvent from the
reaction solution of compound 6 and the dissolution of
the residue in benzene change the color from green (THF)
to blue (benzene). The removal of benzene and recrystalliꢀ
zation of the residue from diethyl ether (blue solution)
gives compound 6 as dark blue crystals in 57% yield
(Scheme 2). In the case of calcium derivative 7, the reꢀ
placement of the solvent from THF to toluene does not
change the color of the solution. Compound 7 was isolatꢀ
ed from toluene as nearly black crystals in 72% yield (see
Scheme 2).
Complexes 6 and 7 were identified on the basis of the
1
IR and Н NMR spectroscopy data. The structures of
compounds 6 and 7 were determined by singleꢀcrystal Xꢀray
analysis. The IR spectra of both compounds contain an
Conditions: i. Excess Zn, ZnI2, THF.
intense band of stretching vibrations of the C—N ordinary
bond of the dianionic FꢀBIAN ligand (1278 cm–1). The
1Н NMR spectra of compounds 6 and 7 exhibit signals of
FꢀBIAN: two doublets, a doublet of doublets, and two
singlets undergoing an upfield shift compared to free FꢀBIAN.
Synthesis and identification of complexes (tmsꢀBIAN)2ꢀ
Zn (8), (FꢀBIAN)2Zn (9), and (FꢀBIAN)3Ga (10). Comꢀ
pound 8 was obtained by the reduction of diimine
tmsꢀBIAN (1) with metallic zinc (granules) in THF in the
presence of 0.5 eq. of zinc iodide (obtained in situ from I2
and Zn). The color of the reaction mixture changes from
orange to brown upon stirring for 8 h. Compound 8 was
isolated from a concentrated solution in 56% yield as light
brown crystals (Scheme 3).
The presence of ZnI2 is not required for the reduction
of diimine FꢀBIAN (2) with granulated zinc. The reaction
occurs for 10 h at ambient temperature with stirring and is
accompanied by a change in the color of the solution from
brown to green. Compound 9 was isolated from a toluene
solution as brown crystals in 68% yield (Scheme 4). An
alternative method for the synthesis of compound 9 is the
exchange reaction of disodium salt (FꢀBIAN)Nа2 (obꢀ
tained in situ from diimine 2 and two equivalents of sodiꢀ
um in diethyl ether) with anhydrous ZnCl2. In this case,
the yield of complex 9 is nearly the same (65%) as in the
first method (68%). Unlike metallic zinc, the reduction of
diimine FꢀBIAN with metallic gallium in toluene occurs
only on prolonged reflux of the reaction mixture (110 С,
20 h). Compound (FꢀBIAN)3Ga (10) was isolated by crysꢀ
tallization from a toluene solution (see Scheme 4) in 80%
yield as dark brown crystals. The reduction of diimine 2
with metallic zinc in pyridine, which was not preꢀdried,
yielded diamine (FꢀBIAN)H2 (11), being, most likely, the
hydrolysis product of the zinc compound with the FꢀBIAN
dianion formed in pyridine.
The ESR study of compounds 8 and 9 in toluene at low
temperatures (150 K) confirmed that they are biradical
complexes with unpaired electrons localized on the ligands
(Fig. 1). The ESR spectra of compounds 8 and 9 exhibit
signals in the halfꢀfield (ms = 2) characteristic of biradiꢀ

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Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
Fedushkin et al.
Scheme 4
Conditions: i. Excess Zn, (1) THF, 20 C, (2) toluene. ii. Excess Ga, toluene, 110 С. iii. (1) THF, 20 C, (2) toluene.
cals. The distances between the geometric centers of loꢀ
calization of unpaired electrons in molecules 8 and 9 calꢀ
culated from the parameters of the ESR spectra are 5.4 Å
(|| = 17.7 mT) and 5.6 Å (|| = 15.8 mT), respectively.
The IR spectra of compounds 8 and 9 contain no bands of
stretching vibration frequencies of the C=N bonds charꢀ
acteristic of free diimines 1 and 2 (1: 1688 and 1669; 2: 1675
and 1652 см–1), but the bands responsible for vibrations of
the sesquialteral C—N bonds in the radicalꢀanion ligands
(8: 1596 and 1524; 9: 1611 and 1518 cm–1).
The ESR spectrum of compound 10 in 2ꢀmethylꢀ
tetrahydrofuran (Fig. 2) at 290 K represents a superposiꢀ
tion of two signals: broadened singlet and quadruplet
(gi = 2.0024, ai(69,71Ga) = 1.62 mT).
The hyperfine structure of the quartet is caused by unꢀ
paired electron splitting on the 69Ga (60.11%, I = 3/2,
N = 2.01659) and 71Ga (39.89%, I = 3/2, N = +2.01659)
nuclei. This signal is probably attributed to the thermally
occupied doublet state of complex (FꢀBIAN)3Ga. The
ESR spectrum in the 2ꢀmethyltetrahydrofuran matrix at
122 K demonstrates signals characteristic of species with
the spin S > 1/2 and the splitting parameters in the zero
field |D||| = 37.0 mT. The distance between the radical
centers calculated in the approximation of point dipoles is
5.3 Å. Unfortunately, the low solubility of the complex in
organic solvents did not allow one to observe ESR signals
corresponding to forbidden transitions ms = 2 and
ms = 3 and characteristic of the quadruplet state of
a species with three unpaired electrons.
a
The magnetic moment of compound 10 is 3.2 B and
remains unchanged in the range from 20 to 300 K (Fig. 3).
The value of magnetic moment is close to that calcuꢀ
lated for the system of three nonꢀinteracting radical anꢀ
ions (eff = [1.732 + 1.732 + 1.732]1/2 = 3 В).
14 mT
b
Synthesis and identification of complex [(dppꢀBIAN)ꢀ
Ca(THF)]2 (12). The singleꢀcrystal Xꢀray results presentꢀ
ed below for metal complexes 3—7 show that no monoꢀ
meric derivatives of magnesium and calcium similar to the
earlier synthesized compounds (dppꢀBIAN)Mg(THF)3
and (dppꢀBIAN)Ca(THF)413 are formed when tmsꢀBIAN
(1) and FꢀBIAN (2) are used as ligands. The smaller (comꢀ
pared to the disubstituted phenyl ring) volume of the Me3Si
group in the case of diimine 1 and the absence of substituꢀ
ents in compound 2 provide the possibility of pyramidalꢀ
ization of the nitrogen atoms in dianions of compounds 1
and 2 and, as a consequence, accessibility of the electron
pair of the nitrogen atoms for the coordination of another
15 mT
Fig. 1. ESR spectra of complexes 8 (а) and 9 (b) in toluene at
150 K. The signals in halfꢀfield are omitted.

Diiminoacenaphthene complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
1819
NC(Me)]2). To obtain a compound with the direct calciꢀ
um—calcium bond, we reduced in situ obtained (dppꢀ
BIAN)CaI(THF)n with metallic potassium in toluene.
Potassium is completely dissolved on stirring with (dppꢀ
BIAN)CaI(THF)n at 80 С for 20 h, and the color of the
solution changes from cherryꢀred to dark green. After
a precipitate of potassium iodide was filtered off and a toluꢀ
ene solution was concentrated, compound [(dppꢀBIAN)ꢀ
Ca(THF)]2 (12) was isolated in 39% yield as dark orthoꢀ
rhombic crystals (Scheme 5).
a
4 mT
1
The Н NMR spectrum of compound 12 in С6D6 is
poorly informative. The spectrum contains broadened sigꢀ
1
b
nals in the aromatic and aliphatic regions. The Н NMR
spectrum of complex 12 in THFꢀd8 is identical to that of
(dppꢀBIAN)Ca(THF)4.13a The crystal structure of comꢀ
pound 12 was determined by the singleꢀcrystal Xꢀray method.
Structures of compounds 3—7 and 9—12. The strucꢀ
tures of compounds 3—12 were determined by the singleꢀ
crystal Xꢀray analysis and are shown in Figs 4—12. Selectꢀ
ed bond lengths in molecules 3—7 and 9—12 are given in
Tables 1—3. The crystallographic data and parameters of
singleꢀcrystal Xꢀray experiments and refinement are listed
in Tables 4—6.
10 mT
Compound 3 in crystal is a centrosymmetric dimer
(see Fig. 4). The magnesium atoms do not almost shift
from the acenaphtheneꢀ1,2ꢀdiimine planes (the deviation
is 0.263 Å). The monomeric units are arranged "headꢀtoꢀ
head" and form a dimer due to the coordination of one of
the nitrogen atoms (N(2)) of the tmsꢀBIAN ligand by the
magnesium atom of the adjacent metal fragment. Due to
this, the coordination environment of the Mg(1), Mg(1а)
and N(2), N(2а) atoms is tetrahedral. Unlike the N(2)
atom, the N(1) atom has a planar trigonal environment.
The difference in the coordination environment of the
N(1) and N(2) atoms leads to noticeable differences in
Mg—N, C—N, and N—Si distances. The Mg(1)—N(1)
(2.019(3)Å), N(1)—C(1) (1.390(5) Å), and N(1)—Si(1)
(1.708(3) Å) distances are appreciably shorter than the
Mg(1)—N(2) (2.146(6)Å), N(2)—C(2) (1.451(5) Å), and
N(2)—Si(2) (1.736(4) Å) distances. Note that the Mg—N
bond, due to which the dimer is formed (Mg(1)—N(2а)
2.086(3) Å), is somewhat shorter than the Mg(1)—N(2)
bond inside the fiveꢀmembered metallocycle.
The magnesium complex containing acenaphtheneꢀ
1,2ꢀdiimine with 2ꢀbiphenyl substituents at the nitrogen
atoms, [(dphꢀBIAN)Mg(THF)]2,19b has a structure simiꢀ
lar to that of compound 3. In this compound, as in comꢀ
pound 3, the Mg—N and C—N distances differ noticeably
because of different coordination environments of the
nitrogen atoms.
It should be mentioned that the alkaliꢀearth metal
derivatives containing the dianionic diimine ligand that
symmetrically chelates the metal atom are green, for
example, (dppꢀBIAN)Mg(THF)3. Complexes 3 and
[(dphꢀBIAN)Mg(THF)]2 have a saturated blue color, the
Fig. 2. ESR spectra of complex 10 in 2ꢀmethyltetrahydrofuran at
290 (а) and 122 K (b).

eff/
B
3.5
3.0
2.5
2.0
1.5
50
100
150
200
250
300 T/К
Fig. 3. Temperature dependence of the magnetic moment of
complex 10 (5 kOe).
molecule by the metal atom. This, in turn, results in the
formation of dimeric structures 3—6. We assume that the
removal of the coordination solvent from compounds
13
13
(dppꢀBIAN)Mg(THF)3 and (dppꢀBIAN)Ca(THF)4
should not induce the formation of dimers with bridging
nitrogen atoms but can result in compounds with the metꢀ
al—metal bond similar to complexes (dppꢀBIAN)Zn—
Zn(dppꢀBIAN), (dppꢀBIAN)Ga—Ga(dppꢀBIAN), and
(dppꢀBIAN)Zn—Ga(dppꢀBIAN),15 as well as guadinꢀ
ates,21a ketiminates,21b and diazadiene21c derivatives
with magnesium—magnesium bonds, LMg—MgL (L =
= [(ArN)2CNPri2], [(ArNCMe)2CH]; Ar = 2,6ꢀPri2C6H3)
and [LMg—MgL][K(THF)3]2 (L = [(2,6ꢀPri2C6H3)ꢀ

1820
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
Fedushkin et al.
Scheme 5
Conditions: i. Excess Ca, THF. ii. THF. iii. (1) Toluene, (2) 2 K, 20 h, 80 C.
same as that for compounds containing two different catꢀ
ions at the dianionic diimine ligand, for example, RMg+
and H+ (see Ref. 22). The color of complex 3, as for other
nonsymmetric complexes of direduced acenaphtheneꢀ1,2ꢀ
diimines, is probably caused by the charge transfer beꢀ
tween two nonequivalent nitrogen atoms.
The unit cell of compound 4 contains two crystalloꢀ
graphically independent binuclear molecules, whose geoꢀ
metric parameters are close. Therefore, the geometry of
only one of them will be considered below.
nificantly. Perhaps, this is related to the longer ion radius
of calcium (Rion(Ca) = 1.00—1.34 Å for the coordination
numbers 6—12)23 compared to magnesium (Rion(Mg) =
= 0.57—0.89 Å for the coordination numbers 6—8)24 and,
as a consequence, to the larger coordination sphere. As
a whole, a molecule of compound 4 can be considered as an
associated ateꢀcomplex containing anion [(tmsꢀBIAN)2ꢀ
Ca(THF)]2– and cation [Ca(THF)2]2+
.
On going from magnesium compound 3 to calcium
derivative 4 (Fig. 5), the molecular geometry changes sigꢀ
O(3)
Si(2)
O(2)
Si(1)
C(2)
N(1)
Si(2)
N(1) C(1)
O(1)
Ca(2)
C(3)
N(2)
Si(3)
N(3)
C(1)
Si(1)
Mg(1)
C(2)
N(2)
Ca(1)
O(1)
N(2A)
C(4)
Si(4)
Mg(1A)
O(1A)
Fig. 4. Molecular structure of compound 3. Hydrogen atoms
Fig. 5. Molecular structure of compound 4. Hydrogen atoms
are omitted.
are omitted.

Diiminoacenaphthene complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
1821
The Ca(1) atom in the [(tmsꢀBIAN)2Ca(THF)]2–
fragment is coordinated nonequivalently by two tmsꢀBIAN
ligands. The dihedral angle between the N(1)C(1)—
C(2)N(2) and Ca(1)N(1)N(2) planes is 118.3, whereas
a similar parameter between the planes N(3)C(3)C(4)N(4)
and Ca(1)N(3)N(4) is 22.8. The Ca(1) atom shifts from
the plane of the N(1)C(1)C(2)N(2) fragment by 1.646 Å,
and its shift from the N(3)C(3)C(4)N(4) plane by 0.797 Å.
The Ca(1)—N distances range from 2.367(3) to 2.531(3) Å.
Note that the Ca(1)—N(1) and Ca(2)—N(2) distances
(2.367(3), 2.449(3) Å) are significantly shorter than
Ca(1)—N(3) and Ca(1)—N(4) (2.489(3), 2.531(3) Å).
The interaction between the Ca(2) and N(2) atoms
(2.369(3) Å) considerably elongates the N(2)—C(2) disꢀ
tance (1.437(5) Å) compared to other N—C distances
(1.357(5)—1.419(5) Å). In addition, the Ca(2) atom is
coordinated according to the 4 type by the N(3)N(4)—
C(3)C(4) fragment. The Ca(2)—N(3), Ca(2)—N(4),
Ca(2)—C(3), and Ca(2)—C(4) distances are 2.432(3),
2.525(3), 2.581(4), and 2.650(3) Å, respectively. These
distances are typical of the interaction of calcium with the
ꢀsystem of the anion, for instance, the Са—5ꢀС disꢀ
tances in (C5Me5)2Ca are 2.597—2.680 Å. The C—N and
C—C bond lengths in both metallocycles are within the
range of values typical of dianions of acenaptheneꢀ1,2ꢀ
diimines (see Table 1).
Table 1. Selected bond lengths (d) in compounds 3, 4, and 5
Bond
d/Å
3а
4b
5c
M(1)—N(1)
M(1)—N(2)
M(1)—N(3)
M(1)—N(4)
M(1)—N(1а)
M(1)—N(2а)
M(2)—N(1)
M(2)—N(2)
M(2)—N(3)
M(2)—N(4)
M(1)—O(1)
M(1)—O(2)
M(2)—O(3)
M(2)—O(4)
C(1)—N(1)
C(2)—N(2)
C(1)—C(2)
C(3)—N(3)
C(4)—N(4)
C(3)—C(4)
M(2)—C(3)
M(2)—C(4)
2.019(3)
2.146(6)
—
—
4.029(4)
2.086(3)
2.367(1)
2.449(1)
2.531(1)
2.489(1)
—
2.563(2)
2.597(2)
2.544(9)
—
—
—
—
—
—
—
—
—
2.735(1)
2.758(1)
2.626(2)
2.536(2)
2.685(1)
2.624(0)
2.633(0)
2.639(1)
1.386(0)
1.410(1)
1.398(0)
1.426(0)
1.353(0)
1.419(0)
2.925(2)
—
2.369(1)
2.432(2)
2.525(1)
2.416(1)
2.402(1)
2.375(1)
—
1.356(1)
1.437(1)
1.416(1)
1.419(1)
1.399(1)
1.387(1)
2.581(4)
2.650(3)
2.031(4)
—
—
—
1.390(6)
1.450(5)
1.383(6)
—
—
—
—
—
а 3: M(1) = Mg(1); b 4: M(1) = Ca(1), M(2) = Ca(2);
c 5: M(1) = Eu(1), M(2) = Eu(2).
Going from magnesium complex 3 to calcium comꢀ
plex 4 and further to europium complex 5 is accompanied
by an increase in the total number of tetrahydrofuran molꢀ
ecules coordinatively bound by the metal atoms. Note that
the structural motive of complex 5 have common features
with structures 3 and 4.
Eu(1)—N(1), Eu(1)—N(2), Eu(2)—N(3), and Eu(2)—N(4)
distances are 2.563(2), 2.597(2), 2.626(2), and 2.536(2) Å,
respectively. The Eu(1) atom, as the magnesium atoms
in complex 3, interacts with one of the nitrogen atoms
(N(3)) of the adjacent metal fragment, whereas the Eu(2)
atom lies above the Eu(1)N(1)C(1)C(2)N(2) metallaꢀ
cycle similarly to the arrangement of the Ca(2) atom
the structure of complex 4. The Eu(1)—N(3) distance
is 2.5449(19) Å. It is most likely that the Eu(1)—N(3)
interaction results in a substantial elongation of the
Eu(2)—N(3) bond (2.626(2) Å) compared to other chelate
Eu—N distances (2.536(2)—2.597(2) Å). In addition,
the Eu(1)—C(3) distance in 5 is 2.925(2) Å, which someꢀ
what exceeds the Eu—8ꢀC (2.756—2.913 Å, dianion)
and Eu—5ꢀC (2.756—2.812 Å, anion) distances in
(C5Me5)2Euꢀ2:8ꢀC8H8 (see Ref. 25). As a result of these
interactions, the N(3) atom gains a distorted tetrahedral
coordination and the N(3)—C(3) distance (1.426(3) Å)
noticeably exceeds similar distances in 5 (1.353(3)—
1.410(3) Å). However, these values are within the ranges
observed in the dianionic diimine ligands. The Eu(2)
atom is 4ꢀcoordinated by the N(1)N(2)C(1)C(2) fragꢀ
ment. The Eu(2)—N(1), Eu(2)—N(2), Eu(2)—С(1), and
Eu(2)—С(2) distances are 2.735(2), 2.758(2), 2.819(2),
and 2.826(2) Å, respectively. These distances are typical
of the interaction of europium with ꢀsystems of anions
and dianions.26
In the structure of compound 5 (see Fig. 6), each of
two tmsꢀBIAN ligands chelates only one metal atom. The
Si(4)
N(4)
O(4)
C(4)
Eu(2)
Si(3)
N(3)
C(3)
O(3)
C(1)
Si(1)
N(1)
N(2)
Eu(1)
C(2)
O(2)
Si(2)
O(1)
Fig. 6. Molecular structure of compound 5. Hydrogen atoms
are omitted.

1822
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
Fedushkin et al.
Complexes 6 and 7 are isostructural. Note that comꢀ
pound 6 contains two different coordination solvents: the
Mg(1) atom coordinates one diethyl ether molecule,
and the Mg(2) atom coordinates two tetrahydrofuran
molecules.
O(2)
O(1)
Ca(1)
The presence of two different solvents in one molecule
is due to the fact that complex 6 was synthesized in THF
and recrystallized from diethyl ether. Compounds 6 and 7
can be interpreted as associated ateꢀcomplexes containing
the bis(ligand) anion [(FꢀBIAN)2M(L)n]2– and cation
[M(THF)2]2+. The coordination environments of the
Mg(1) and Ca(1) atoms are a distorted trigonal bipyramid
and an octahedron with the N(1) and N(3) atoms in the
axial positions. The Mg(2) and Ca(2) atoms are in the
distorted tetrahedral environment of two nitrogen atoms
of the FꢀBIAN ligands and two oxygen atoms of the tetraꢀ
hydrofyran molecules. As in previous cases, the distances
from the M(1) atoms to the N(2) and N(4) nitrogen atoms
(5: Mg(1)—N(2) 2.226(2) Å, Mg(1)—N(4) 2.2387(19) Å;
6: Ca(1)—N(2) 2.538(4) Å, Ca(1)—N(4) 2.463(4) Å) involvꢀ
ed in bonding with the M(2) atoms are longer than the
bond lengths M(1)—N(1) and M(1)—N(3) (6: Mg(1)—N(1)
2.0981(18) Å, Mg(1)—N(3) 2.1096(18) Å; 7: Ca(1)—N(1)
2.437(4) Å, Ca(1)—N(3) 2.441(3) Å). Interestingly, the
shortest metal—nitrogen bonds in complexes 6 and 7 are
bonds of the bridging atoms N(2) and N(4) with the Mg(2)
and Ca(2) atoms, respectively (6: Mg(2)—N(2) 2.063(1)
and Mg(2)—N(4) 2.067(1) Å; 7: Ca(2)—N(2) 2.349(1)
and Ca(2)—N(4) 2.396(2) Å). The dianionic character of
the FꢀBIAN ligands in compounds 6 and 7 is confirmed
by the singleꢀcrystal Xꢀray data. The C—N and C—C bond
lengths (see Table 2) in the diimine fragments are close to
N(1)
C(1)
C(2)
N(3)
C(3)
N(4)
C(4)
N(2)
O(4)
Ca(2)
O(3)
Fig. 8. Molecular structure of compound 7. Hydrogen atoms
are omitted.
the corresponding values in the dppꢀBIAN dianion in
(dppꢀBIAN)Mg(THF)313 and (dppꢀBIAN)Ca(THF)4.13
A molecule of complex 9 (see Fig. 9) lies on the 2ꢀfold
rotation axis passing through the zinc atom. Therefore,
the both diimine ligands are geometrically equivalent. The
zinc atom in compound 9 has a distorted tetrahedral
environment. The dihedral angle between the planes of
the diimine ligands is 84, which minimizes the nonvalent
Table 2. Selected bond lengths (d) in compounds 6, 7, and 9
Bond
d/Å
6а
7b
9c
M(1)—N(1)
M(1)—N(2)
M(1)—N(3)
M(1)—N(4)
M(2)—N(2)
M(2)—N(4)
M(1)—O(1)
M(1)—O(2)
M(1)—O(3)
M(2)—O(1)
M(2)—O(2)
M(2)—O(3)
M(2)—O(4)
C(1)—N(1)
C(2)—N(2)
C(1)—C(2)
C(3)—N(3)
C(4)—N(4)
C(3)—C(4)
2.098(1)
2.226(1)
2.1096(1)
2.239(1)
2.063(1)
2.067(1)
.—
2.437(1)
2.538(2)
2.441(3)
2.463(4)
2.349(1)
2.396(2)
2.412(2)
2.376(1)
—
2.003(1)
2.022(1)
—
—
—
—
—
—
—
—
O(3)
Mg(1)
N(1)
N(3)
.—
C(1)
C(3)
2.113(1)
2.00(1)
2.009(1)
.—
—
—
C(2)
—
—
—
N(2)
2.343(1)
2.315(1)
1.382(1)
1.426(1)
1.371(1)
1.359(1)
1.420(1)
1.413(1)
N(4)
C(4)
.—
Mg(2)
1.367(1)
1.434(1)
1.393(1)
1.377(1)
1.436(1)
1.377(1)
1.338(1)
1.342(1)
1.432(1)
—
O(2)
O(1)
—
—
Fig. 7. Molecular structure of compound 6. Hydrogen atoms
are omitted.
а 6: M(1) = Mg(1), M(2) = Mg(2); b 7: M(1) = Ca(1),
M(2) = Ca(2); c 9: M(1) = Zn.

Diiminoacenaphthene complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
1823
the calcium atom is bounded to two nitrogen atoms of the
dppꢀBIAN ligand and the oxygen atom of the THF moleꢀ
cule. The dimeric structure is formed due to the ꢀcoordiꢀ
nation of the calcium atoms with one of the phenyl rings
of the adjacent dppꢀBIAN ligand. A similar coordination
mode is observed in complex {dppBIAN Na}2.26 The
Ca(1)—6ꢀС(13—18) distances are 2.752(2)—3.034(2) Å
and somewhat shorter than similar distances (3.046—3.181 Å)
N(1)
in
[1ꢀ(2´,4´,6´ꢀtriisopropylbiphenylꢀ2ꢀyl)ꢀ3ꢀ(6ꢀ
C(1)
C(2)
Zn
2,2,4,4,6,6ꢀhexamethylꢀ1,1´:3´,1ꢀterphenylꢀ2´ꢀyl)ꢀ
triazenidoꢀN,N´](pentafluorophenyl)tetrahydrofuran)ꢀ
calcium.27 The Ca—N distances in compound 12 are
2.270(2) and 2.284(2) Å, which are noticeably shorter than
those in the fiveꢀcoordinate monomeric derivative (dppꢀ
BIAN)Ca(THF)3 (2.345(1) and 2.290(1) Å). The bond
lengths in the diimine moiety of the ligand in compound 12
(C(1)—N(1) 1.402(2), C(2)—N(2) 1.384(2), С(1)—С(2)
1.406(2) Å) are close to the corresponding values in
the (dppꢀBIAN)Ca(THF)4 complex (C—N 1.384(3) Å,
С(1)—С(2) 1.397(3) Å) also containing the dppꢀBIAN
dianion.13a
Thus, in this work we reported the synthesis of comꢀ
pounds of diverse metals with the reduced forms of
two 1,2ꢀdiimines rarely used as ligands and based on
acenaphthene: 1,2ꢀbis(trimethylsilylimino)acenaphthene
(tmsꢀBIAN) and 1,2ꢀbis{[3,5ꢀbis(trifluoromethylphenyl)ꢀ
imino}acenaphthene (FꢀBIAN). The study of the strucꢀ
tures of the synthesized complexes showed that the lower
shielding capacity and conformational mobility of these
two ligands compared to those of widely used 1,2ꢀbis[(2,6ꢀ
diisopropylphenyl)]imino}acenaphthene (dppꢀBIAN) do
N(2)
Fig. 9. Molecular structure of compound 9. Hydrogen atoms
are omitted.
interactions between the 3,5ꢀ(CF3)2С6H3 groups. On goꢀ
ing from the complexes with the BIAN dianion to those
with the radical anion, one should expect the elongation
of the metal—ligand bonds because of weakening of the
interaction of the cation with anion. However, since none
of zinc derivatives containing the acenaphtheneꢀ1,2ꢀdiꢀ
imine ligand in the dianionic state is presently known,
these parameters cannot be compared. Along with the ESR
data, the values of bond lengths in diimine fragment 9
indicate the radicalꢀanion character of both ligands.
C(1)—N(1) and C(2)—N(2) bond lengths are 1.338(1)
and 1.342(1) Å and nearly coincide with those in (dppꢀ
BIAN)Zn—Zn(dppꢀBIAN)15a (1.338(2) and 1.340(2) Å).
According to the singleꢀcrystal Xꢀray data, compound
10 is the tris(ligand) homoleptic complex lying on the
2ꢀfold axis (see Fig. 10). The gallium atom is chelated by
three FꢀBIAN ligands and has an almost ideal octahedral
coordination. The crystallographically independent disꢀ
tances Ga—N are in a narrow range of 2.090(1)—2.098(1) Å
(see Table 3) as the bond lengths in the diimine fragments
of the ligands (N—C 1.331(3)—1.336(3) Å, С—С 1.425(4)—
1.440(3) Å) and confirm their radicalꢀanion character.
A molecule of compound 11 is an E,Еꢀisomer (see
Fig. 11). The C(1)—N(1) (1.406(2) Å) and C(2)—N(2)
bonds (1.397(3) Å) are ordinary and noticeably elongated
compared to the C—N bonds in compounds 9 and 10
containing FꢀBIAN in the radicalꢀanion form. On the
contrary, the С(1)–С(2) bond (1.363(1) Å) is shortened
compared to the corresponding bonds (1.432(2), 1.440(3) Å)
in compounds 9 and 10.
C(2)
N(2)
C(1)
N(1A)
Ga
N(1)
N(3)
N(2A)
N(3A)
In crystal molecules of complex 12 form a centroꢀ
symmetric dimer (see Fig. 12). In each of two fragments,
Fig. 10. Molecular structure of compound 10. Hydrogen atoms
are omitted.

1824
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
Fedushkin et al.
catalysts of polymerization with ring opening in lactides
and lactones and hydroamination of alkenes and alkynes.
Experimental
The synthesized compounds are sensitive to air oxygen and
moisture and, hence, all procedures on synthesis, isolation, and
identification were carried out in vacuo using Schlenk technique.
The starting compounds FꢀBIAN28, tmsꢀBIAN,18 and dppꢀ
BIAN29 were synthesized using known procedures. Toluene, hexꢀ
ane, diethyl ether, and THF were dried and stored above sodium
benzophenone ketyl and samples by condensation in vacuo prior
to use. Deuterated solvents C6D6, THFꢀd8, and tolueneꢀd8
(Aldrich) were dried above sodium benzophenone ketyl and samꢀ
ples by condensation with a tube for NMR spectra recording
already containing a sample of the compound. The yields of
products 3—12 indicated in the synthesis procedures were based
on the amount of the initial FꢀBIAN, dppꢀBIAN, and tmsꢀBIAN
taken for the reactions. Melting points were determined in sealed
capillaries. Suspensions of compounds in Nujol were prepared
for IR spectra recording. IR spectra were recorded on an FSMꢀ
1201 instrument. 1Н NMR spectra were obtained on a Bruker
DPXꢀ200 spectrometer. ESR spectra were measured with a Brukꢀ
er EMX spectrometer.
N(1)
H(1)
N(2)
C(2) C(1)
H(2)
Fig. 11. Molecular structure of compound 11. Hydrogen atoms
are omitted.
N(1)
N(2)
C(1)
C(2)
Ca(1´)
Ca(1)
1,2ꢀBis(trimethylsilylimino)acenaphthenemagnesium tetraꢀ
hydrofuranate (3). A mixture of metallic magnesium (1.5 g,
61.7 mgꢀat.) and tmsꢀBIAN (0.32 g, 1.0 mmol) in THF (25 mL)
was magnetically stirred for 4 h at ~20 С. The obtained blue
solution was decanted from a magnesium excess. The solvent
was removed in vacuo, and the residue was dissolved in toluene
(20 mL) on heating. Compound 3 was obtained by crystalꢀ
lization from toluene in a yield of 0.27 g (65%) as dark blue
crystals, m.p. 217 C. Found (%): C, 62.57; H, 7.59; N, 6.61.
C44H64MgN4Si4O2. Calculated (%): C, 62.77; H, 7.66 N, 6.65.
IR (/cm–1): 1614 w, 1588 w, 1444 s, 1357 m, 1303 s, 1242 s,
1181 w,1144 w, 1126 m, 1071 m, 1008 m, 959 s, 923 s, 840 s, 766 m,
737 m, 601 m. 1Н NMR (200 MHz, THFꢀd8, 20 С), : 0.27
(s, 18 Н, SiMe3); 1.70—1.82 (m, 8 Н, THF); 3.55—3.68 (m, 8 Н,
THF); 7.10—7.50 (m, arom., 6 Н).
Bis[1,2ꢀbis(trimethylsilylimino)acenaphthene]dicalcium trisꢀ
tetrahydrofuranate (4). Metallic calcium (1.2 g, 29.9 mgꢀat.) and
tmsꢀBIAN (0.36 g, 1.1 mmol) in THF (25 mL) were magneticalꢀ
ly stirred on heating (80 С) for 2 h. The obtained blue solution
was decanted from a calcium excess. After concentrating, comꢀ
pound 4 was obtained in a yield of 0.3 g (57%) as dark blue
crystals, m.p. 170 C. Found (%): C, 61.64; H, 7.99; N, 4.57.
C48H72CaN4Si4O3•2.75(С4H8O). Calculated (%): C, 61.95;
H, 8.28; N, 4.89. IR (/cm–1): 1672 w, 1614 w, 1584 w, 1443 w,
1349 m, 1303 s, 1239 s, 1147 m, 1130 m, 1098 m, 1067 s, 1030 s,
1003 m, 950 s, 923 s, 829 s, 768 m, 669 m. 1Н NMR (200 MHz,
С6D6, 20 С), : 0.43 (s, 18 Н, Si(Me)); 1.75—1.82 (m, 8 Н,
THF); 3.60—3.67 (m, 8 Н THF); 7.22 (dd, 2 Н, arom., J = 7.0 Hz,
J = 7.8 Hz); 7.24 (d, 2 Н, arom., J = 6.5 Hz); 7.30 (d, 2 Н,
arom., J = 7.5 Hz).
Fig. 12. Molecular structure of compound 12. Hydrogen atoms
are omitted.
not allow monomeric metal complexes, including those
containing the metal—metal bond, to be obtained. At the
same time, the pronounced electronꢀacceptor character
of 3,5ꢀbis(trifluoromethyl)phenyl substituents makes it
possible to directly reduce FꢀBIAN with less active metals
(compared to alkaliꢀearth metals), for instance, zinc. We
believe that the synthesized metal compounds can be active
Table 3. Selected bond lengths (d) in compounds 10, 11, and 12
Bond
d/Å
10а
11
12b
M(1)—N(1)
M(1)—N(2)
M(1)—N(3)
M(1)—O(1)
C(1)—N(1)
C(2)—N(2)
C(1)—C(2)
M(1)—C(Phꢀ2,6ꢀiPr2)
2.090(1)
2.098(1)
2.097(1)
—
1.336(1)
1.331(1)
1.439(1)
—
—
—
—
2.270(2)
2.284(2)
—
2.326(2)
1.402(2)
1.384(2)
1.406(2)
2.752(2)—
3.034(2)
—
1.406(1)
1.397(1)
1.363(1)
—
Bis[1,2ꢀbis(trimethylsilylimino)acenaphthene]dieuropium tetraꢀ
kis(tetrahydrofuranate) (5) A mixture of pieces of metallic euroꢀ
pium (1.2 g, 7.9 mgꢀat.) and tmsꢀBIAN (0.33 g, 1.0 mmol) in
THF (25 mL) was magnetically stirred on heating (80 С) for
2 h. The obtained blue solution was decanted from an europium
excess, centrifuged, and decanted from an europium dust. After
а 10: M = Ga; b 12: M = Ca(1).

Diiminoacenaphthene complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
1825
concentrating, compound 5 was obtained in a yield of 0.41 g
(65%) as dark blue crystals, m.p. 118 C. Found (%): C, 51.89;
H, 6.69; N, 3.98. C52H80Eu2N4Si4O4•2(С4Н8O). Calculated (%):
C, 52.01; H, 6.98; N, 4.04. IR (/cm–1): 1673 w, 1615 w, 1580 w,
1563 w, 1552 w, 1352 m, 1303 s, 1250 s, 1173 w, 1142 w, 1133 w,
1123 w, 1198 w, 1070 s, 1034 m, 1003 m, 946 s, 923 s, 838 s, 767 m,
661 m, 630 w, 615 w, 565 m, 526 m, 491 w, 452 w, 424 m, 413 s.
Bis{[1,2ꢀbis(3,5ꢀtrifluoromethylphenyl)imino]acenaphthene}ꢀ
magnesium bis(tetrahydrofuranate)magnesium diethyl etherate (6).
Chips of metallic magnesium (1.2 g, 49.3 mgꢀat.) and FꢀBIAN
(0.5 g, 0.83 mmol) in THF (25 mL) were magnetically stirred for
10 h. The obtained green solution was decanted from a magneꢀ
sium excess. After the solvent was removed in vacuo, benzene
(30 mL) was added to the residue. The solution turned dark blue.
Benzene was removed, and the recrystalization of the residue
from diethyl ether gave compound 6 in a yield of 0.34 g (57%) as
dark blue crystals, m.p. 190 C (decomp.). Found (%): C, 56.53;
H, 3.59; N, 3.18. C68H50Mg2N4F24O4•(C4H10O·C6H6). Calcuꢀ
lated (%): C, 56.69; H, 3.99 N, 3.53. IR (/cm–1): 1600 s, 1509 s,
1341 m, 1278 s, 1176 s, 1125 s, 1089 m, 1062 m, 1038 m, 1008 s,
990 m, 966 s, 960 m, 912 m, 885 w, 864 m, 840 m, 819 m, 798 w,
771 s, 750 s, 738 w, 711 m, 678 s, 639 w, 627 m, 612 w, 594 m,
576 w, 528 w, 516 w, 477 w, 450 m, 438 m, 417 m. 1Н NMR
(200 MHz, tolueneꢀd8, 20 С), : 1.75—1.82 (m, 8 Н, THF);
3.60—3.67 (m, 8 Н, THF); 6.63 (s, 2 Н, arom.); 6.87 (d, 2 Н,
arom., J = 6.8 Hz); 6.97 (dd, 2 Н, arom., J = 7.2 Hz, J = 7.8 Hz);
7.01 (s, 4 Н, arom.); 7.12 (d, 2 Н, arom., J = 7.2 Hz).
Bis{[1,2ꢀbis(3,5ꢀtrifluoromethylphenyl)imino]acenaphthene}ꢀ
dicalcium tetrakis(tetrahydrofuranate) (7). Pieces of metallic calꢀ
cium (1.2 g, 29.9 mgꢀat.) and FꢀBIAN (0.5 g, 0.83 mmol) in
THF (25 mL) were magnetically stirred for 10 h. The obtained
green solution was decanted from a calcium excess. After the
solvent was removed in vacuo, toluene (50 mL) was added to the
residue. The concentrated solution gave compound 7 in a yield
of 0.47 g (72%) as black crystals, m.p. 202 C. Found (%):
C, 56.53; H, 3.69; N, 3.18. C72H56CaN4F24O4•(С7Н8). Calcuꢀ
lated (%): C, 56.84; H, 3.86; N, 3.36. IR (/cm–1): 1593 m, 1503 m,
1338 m, 1278 s, 1176 s, 1140 s, 1116 s, 1065 m, 1109 w, 1002 w,
984 w, 957 m, 900 w, 873 w, 840 w, 819 m, 801 w, 771 m, 747 w,
732 m, 705 m, 681 s, 627 m, 606 w, 591 m, 525 w, 513 w, 465 w,
444 w, 432 w. 1Н NMR (200 MHz, THFꢀd8, 20 С), : 1.75—1.82
(m, 8 Н, THF); 3.60—3.67 (m, 8 Н, THF); 6.50 (s, 2 Н, arom.);
6.97 (dd, 2 Н, arom., J = 6.5 Hz); 7.02 (s, 4 Н, arom.); 7.08
(d, 2 Н, arom., J = 6.7 Hz); 7.23 (d, 2 Н, arom., J = 7.0 Hz).
Bis[1,2ꢀbis(trimethylsilylimino)acenaphthene]zinc (8). A soluꢀ
tion of iodine (0.16 g, 0.63 mmol) in THF (40 mL) was added to
a granulated zinc excess (1.5 g, 22.9 mgꢀat.). After the reaction
mixture completely decolorized, dimine tmsꢀBIAN (0.4 g,
1.23 mmol) was added, and the mixture was further magnetically
stirred for 8 h at ambient temperature. After the appearance of
a stable brown color, the solution was decanted from a zinc excess.
Compound 8 was isolated from a concentrated solution (15 mL)
as yellowꢀbrown crystals. The yield was 0.27 g (56%), m.p. >300 С
(decomp.). Found (%): С, 60.23; Н, 6.57; N, 7.54. C36H48Si4N4Zn.
Table 4. Crystallographic data and parameters of singleꢀcrystal Xꢀray experiments and refinement for complexes 3, 4, and 5
Parameter
3
4
5
Empirical formula
C44H64Mg2N4O2Si4 C48H72Ca2N4O3Si4•2.75C4H8O C52H80Eu2N4O4Si4•2C4H8O
Molecular weight
Crystal system
Space group
841.97
Monoclinic
P21/n
1143.90
Monoclinic
P21/n
1385.69
Monoclinic
P21/с
a/Å
b/Å
c/Å
/deg
11.2832(5)
14.2836(7)
14.9842(6)
90.00
23.9301(11)
14.9575(7)
35.2801(17)
90.00
12.4611(4)
14.0859(4)
36.8737(11)
90.00
/deg
102.225(4)
90.00
2360.16(18)
2
93.994(1)
90.00
12597.3(10)
8
98.840(1)
90.00
6395.4(3)
4
1.439
2.068
/deg
V/Å3
Z
/g cm–3
1.185
0.191
1.206
0.306
/mm–1
F(000)
904
4944
2856
Crystal sizes
Measurement range, /deg
Range indices
0.5×0.11×0.09
2.91—25.00
–13  h  13
–16  k  16
–17  l  17
0.25×0.12×0.08
1.69—27.00
–27  h  30
–17  k  19
–45  l  41
0.28×0.10×0.05
2.13—27.50
–16  h  16
–18  k  18
–47  l  47
Number of reflections
observed
independent
21012
4150
80125
27423
60239
14645
Rint
0.1126
0.1459
0.0543
GOOF
1.157
1.001
1.031
R1/wR2 (I > 2(I))
R1/wR2 (for all parameters)
Residual electron
0.0883/0.1206
0.1632/0.1414
0.257/–0.252
0.1049/0.2235
0.1985/0.2585
1.229/–1.211
0.0378/0.0736
0.0571/0.0778
1.124/–0.988
density/е Å–3, max/
min

1826
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
Fedushkin et al.
Calculated: C, 60.52; H, 6.77; N, 7.84. IR (/cm–1): 1596 w,
1524 s, 1248 s, 1149 s, 1131 w, 1113 s, 1071 w, 1014 s, 951 s,
837 s, 768 m, 687 m, 618 w, 591 w, 438 w. ESR (toluene, 150 K):
|| = 17.66 mT, |E| = 0.3 mT (r = 5.39 Å).
Tris{[1,2ꢀbis(3,5ꢀtrifluoromethylphenyl)imino]acenaphthꢀ
ene}gallium (10). A mixture of gallium (5 g, 71.7 mgꢀat.) and
diimine FꢀBIAN (0.5 g, 0.83 mmol) in toluene (35 mL) was
heated to 110 С for 20 h. The obtained brown solution was
decanted from a gallium excess. Compound 10 was isolated
from the concentrated solution in a yield of 0.45 g (80%) as
dark brown crystals, m.p. 243—245 С. The magnetic moment
Bis{[1,2ꢀbis(3,5ꢀtrifluoromethylphenyl)imino]acenaphthene}ꢀ
zinc (9). A. Granulated metallic zinc (1.5 g, 22.9 mgꢀat.) and
FꢀBIAN (0.5 g, 0.83 mmol) in THF (25 mL) were magnetically
stirred. In 10 h, the obtained green solution was decanted from
a zinc excess. After the solvent was replaced by toluene (30 mL),
the solution turned brown. The concentrated solution yielded
0.35 g (68%) of compound 9 as brown crystals, m.p. 278 C.
Found (%): C, 52.53; H, 1.59; N, 4.28. C56H24ZnN4F24. Calcuꢀ
lated (%): C, 52.79; H, 1.89 N, 4.39. IR (/cm–1): 1611 s, 1518 s,
1344 s, 1275 s, 1191 m, 1170 s, 1137 s, 1104 m, 1068 m, 1047 m,
1005 m, 987 m, 972 w, 948 s, 909 s, 891 w, 876 s, 861 m, 843 w,
819 s, 768 s, 750 m, 684 s, 645 m, 624 m, 594 m, 582 w, 462 w,
44 w, 415 s. ESR (toluene, 150 K): || = 15.80 mT, |E| = 0.5 mT,
(r = 5.61 Å).
B. Anhydrous ZnCl2 (0.12 g, 0.88 mmol) was added to
a solution of (FꢀBIAN)Na2 obtained from sodium (0.04 g,
1.74 gꢀat.) and diimine FꢀBIAN (0.53 g, 0.88 mmol) in diethyl
ether. The color of the reaction mixture immediately changed
from brown to green. After NaCl was filtered off, the solvent was
removed in vacuo and the residue was dissolved in toluene. Comꢀ
pound 9 was isolated by crystallization from toluene as brown
crystals (0.26 g, 45%). The IR and ESR spectra of the obtained
crystals are identical to the spectra presented above.
is  = 3.2 В. Found (%): С, 56.63; Н, 2.30; N, 3.99.
eff
C84H36F36GaN6•2(C7H8). Calculated (%): С, 56.94; Н, 2.51,
N, 4.07. IR (/cm–1): 2924 s, 2853 s, 1803 w, 1604 m, 1548 s,
1484 s, 1423 m, 1359 s, 1303 w, 1273 s, 1247 m, 1175 s, 1145 s,
1104 s, 1043 w, 1017 m, 979 m, 938 m, 908 m, 889 m, 859 m,
852 m, 814 m, 765 m, 709 s, 682 s, 637 w, 618 w, 611 w, 658 w,
543 w, 509 w, 468 w. ESR (2ꢀmethyltetrahydrofuran, 290 K):
gi = 2.0024, ai(69,71Ga) = 16.2 Oe.
1,2ꢀBis[(3,5ꢀtrifluoromethylphenyl)amino]acenaphthene (11).
A mixture of metallic zinc (1.5 g, 22.9 mgꢀat.) and FꢀBIAN
(0.3 g, 0.5 mmol) in pyridine (25 mL) not preꢀdried was magnetꢀ
ically stirred for 10 h on heating at 110 С. The obtained brown
solution was decanted from zinc excess. The solvent was reꢀ
moved in vacuo, and hexane (30 mL) was added to the residue.
After concentrating of the solution, compound 11 was obtained
in a yield of 0.18 g (59%) as brown crystals, m.p. 278 C. Found (%):
C, 55.23; H, 2.29; N, 4.36. C28H14N2F12. Calculated (%): C, 55.46;
H, 2.32 N, 4.62. IR (/cm–1): 3373 m, 3055 w, 2952 m, 2921 s,
2854 s, 1939 w, 1879 w, 1817 w, 1761 w, 1742 w, 1732 w, 1621 s,
1597 m, 1586 m, 1512 m, 1464 s, 1431 m, 1379 s, 1325 w, 1277 s,
Table 5. Crystallographic data and parameters of singleꢀcrystal Xꢀray experiments and refinement for complexes 6, 7, and 9
Parameter
6
7
9
Empirical formula
Molecular weight
Crystal system
Space group
C68H50Mg2N4O4F24•C4H10O•C6H6
C72H56Ca2F24N4O4•C7H8
1669.50
C56H24F24N4Zn
1274.18
Monoclinic
C2/c
1588.91
Monoclinic
P21/n
Monoclinic
P21/с
a/Å
b/Å
c/Å
/deg
13.9924(4)
24.0009(7)
22.6334(6)
90.00
13.8958(17)
22.942(3)
23.461(3)
90.00
18.1249(10)
18.0702(11)
16.8469(10)
90.00
/deg
92.257(2)
90.00
7269.4(4)
4
1.452
0.147
100.279(2)
90.00
7359.3(16)
4
1.507
0.270
115.972(1)
90.00
4960.5(5)
4
1.706
0.632
/deg
V/Å3
Z
/g cm–3
/mm–1
F(000)
3252
3416
2536
Crystal sizes
Measurement range, /deg
Range indices
0.14×0.26×0.23
1.80—26.00
–16  h  16
–15  k  29
–27  l  27
0.18×0.15×0.08
1.98—25.00
–16  h  16
–27  k  27
–27  l  27
0.16×0.11×0.10
2.25—26.00
–22  h  20
–13  k  22
–20  l  20
Number of reflections
observed
independent
42820
14133
57840
12925
14816
4872
Rint
0.0359
0.2478
0.0465
GOOF
1.038
0.906
1.018
R1/wR2 (I > 2(I))
R1/wR2 (for all parameters)
Residual electron
0.0685/0.1854
0.1049/0.2063
1.101/–0.844
0.0904/0.1596
0.2326/0.1994
0.0710/–0.423
0.0446/0.0986
0.0656/0.1060
0.576/–0.408
density/е Å–3, max/
min

Diiminoacenaphthene complexes
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
1827
Table 6. Crystallographic data and parameters of singleꢀcrystal Xꢀray experiments and refinement for complexes 10—12
Parameter
10
11
12
Empirical formula
Molecular weight
Crystal system
Space group
a/Å
b/Å
c/Å
/deg
C84H36F36GaN6•2C7H8
2067.18
C28H14F12N2
606.41
Monoclinic
P2/n
16.1834(18)
9.4265(10)
16.6789(19)
90.00
C80H96Ca2N4O2•6C7H8
1778.57
Monoclinic
C2/c
28.8024(14)
13.3317(6)
23.1610(12)
90.00
Monoclinic
P21/n
15.9839(12)
14.6244(11)
22.8849(17)
90.00
/deg
100.46(3)
90.00
8698.0(7)
4
1.579
0.448
101.268(2)
90.00
2495.4(5)
4
1.614
0.158
107.7194(15)
90.00
5095.7(7)
2
/deg
3
V/Å
Z
/g cm–3
1.159
0.165
/mm–1
F(000)
4148
1216
1920
Crystal sizes
Measurement range, /deg
Range indices
0.25×0.23×0.15
1.69—26.50
–36  h  34
–16  k  16
–29  l  21
0.35×010×0.06
1.95—27.00
–20  h  20
–8  k  12
–21  l  19
0.39×0.34×0.31
3.00—29.00
–21  h  21
–19  k  19
–31  l  31
Number of reflections
observed
independent
26693
8941
15392
5384
13540
9682
Rint
0.0393
0.0479
GOOF
1.068
1.0337
1.016
R1/wR2 (I > 2(I))
R1/wR2 (for all parameters)
Residual electron
0.0604/0.1583
0.0866/0.1733
1.065/–0.637
0.0642/0.1576
0.1117/0.1782
0.555/–0.479
0.0513/0.1220
0.0820/0.1471
0.875/–0.506
density/е Å–3, max/
min
1277 s, 1179 s, 1136 s, 1069 w, 1007 w, 999 s, 962 m, 908 w,
872 m, 866 m, 821 m, 700 m, 684 s, 621 w, 542 w. 1Н NMR
(200 MHz, С6D6, 20 С), : 5.23 (s, 2 Н, NH); 6.74 (s, 4 Н);
7.10 (d, 2 Н, arom., J = 6.8 Hz); 7.26 (d, 2 Н, arom., J = 7.0 Hz);
7.52 (d, 2 Н, arom., J = 8.3 Hz).
pound 12 and 3 were obtained on Bruker SMART APEX II and
Oxford Diffraction Xcalibur S Sapphire diffractometers, respecꢀ
tively (the latter was measured at 100 K). The structures were
solved by a direct method and refined by the fullꢀmatrix leastꢀ
squares method for F2 in the anisotropic approximation for all
nonꢀhydrogen atoms using the SHELXTL program.30 The
SADABS31 and SCALE3 ABSPACK32 programs were used to
apply absorption corrections. Hydrogen atoms were placed in
geometrically calculated positions and refined by the riding model
(Uiso(H) = 1.5Ueq(C) in the CH3 groups and Uiso(H) = 1.2Ueq(C)
in other groups). The main crystallographic data and singleꢀ
crystal Xꢀray experimental and refinement parameters are given
in Tables 4—6.
The crystallographic data for complexes 3 (CCDC 913402),
4 (CCDC 913403), 5 (CCDC 913404), 6 (CCDC 913405),
7 (CCDC 913406), 9 (CCDC 913407), 10 (CCDC 913408),
11 (CCDC 913409), and 12 (CCDC 913410) were deposited
with the Cambridge Crystallographic Date Centre. This inꢀ
formation is available on request to CCDC, 12, Union Road,
Cambridge CB2 1 EZ, UK; Fax: +44 11223 336033; eꢀmail:
deposit@ccdc.cam.ac.uk; http://www.ccdc.cam.ac.uk.
1,2ꢀBis[(2,6ꢀdiisopropylphenyl)imino]calcium tetrahydroꢀ
furanate (12). Iodine (0.127 g, 0.5 mmol) was added to a solution
of complex (dppꢀBIAN)Ca(THF)4 (prepared in situ from 0.50 g
(1.0 mmol) of dppꢀBIAN and metallic calcium excess in THF).
The color of the reaction mixture instantly changed from green
to red. After the solvent was removed in vacuo, the residue was
dissolved in toluene (30 mL). Metallic potassium (0.04 g,
1.0 mmol) was added to the formed solution. The resulting mixꢀ
ture was heated at 80 С with stirring for 20 h until potassium
disappeared. The solution turned green. After filtration, the reꢀ
action product was isolated from a concentrated toluene soluꢀ
tion as dark orthorhombic crystals in a yield of 0.47 g (69%),
m.p. 124 С (decomp.). Found (%): C, 82.25; H, 7.84; N, 2.93.
C80H96Ca2N4O2•6(C7H8). Calculated (%): C, 82.39; H, 8.15;
N, 3.15. IR (н/cm–1): 1614 w, 1607 w, 1576 m, 1497 m, 1417 w,
1307 s, 1246 w, 1212 w, 1182 w, 1098 m, 1083 w, 1056 w, 1022 m,
1000 m, 916 s, 859 s, 806 s, 761 s, 726 s, 696 s, 681 s, 620 s, 578 w,
536 s, 510 w, 491 w, 465 s.
The authors are grateful to E. Iran for singleꢀcrystal
Xꢀray analysis of complex 3 and to S. Demeshko for meaꢀ
suring the temperature dependence of the magnetic moꢀ
ment of compound 10.
Singleꢀcrystal Xꢀray analyses of compounds 3—7 and 9—12.
Diffraction data for compounds 4—7 and 9—11 were obtained
on a Bruker SMART APEX diffractometer, and those for comꢀ

1828
Russ.Chem.Bull., Int.Ed., Vol. 62, No. 8, August, 2013
Fedushkin et al.
15. (a) I. L. Fedushkin, A. A. Skatova, O. V. Eremenko, M. Humꢀ
mert, H. Schumann, Z. Anorg. Allg. Chem., 2007, 633, 1739;
(b) I. L. Fedushkin, A. N. Lukoyanov, S. Yu. Ketkov,
M. Hummert, H. Schumann, Chem. Eur., 2007, 13, 7050.
16. I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, N. M.
Khvoinova, A. Yu. Baurin, S. Dechert, M. Hummert,
H. Schumann, Organometallics, 2004, 23, 3714.
This work was financially supported by the Ministry of
Education and Science of the Russian Federation (state
contract No. 14.740.11.0613).
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Received April 16, 2013;
in revised form May 23, 2013