Synthesis and structure of bischelate gallium complexes (dpp-bian)Ga(acac) and (dpp-bian)Ga(2,2′-bipy) (dpp-bian is 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene)

Article abstract of DOI:10.1007/s11172-016-1433-9

A reaction of digallane [(dpp-bian)Ga—Ga(dpp-bian)] (1) (dpp-bian is the 1,2-bis[(2,6-disopropylphenyl)imino]acenaphthene) with one equivalent of I₂ leads to oxidation of (dpp-bian)^2– in compound 1 to (dpp-bian)–and gives [(dpp-bian)GaI—GaI(dpp-bian)] (2). In the reaction of compound 2 with two equivalents of (acac)Na, not only exchange of the iodide and acetylacetonate ions takes place, but also a transfer of electrons from the metal—metal bond to dpp-bian with the formation of the complex [(dpp-bian)Ga(acac)] (3), in which the dpp-bian ligand is a dianion. A reaction of digallane 1 with 2,2′-bipyridyl at 200 °C in toluene in a sealed tube leads to the reduction of 2,2′-bipyridyl and gives the complex [(dpp-bian)Ga(bipy)] (4), which contains two different chelate redox-active ligands. The new compounds were characterized by IR (3, 4), NMR (3), and ESR spectra (4), the structures of both derivatives were established by X-ray diffraction.

Full text of DOI:10.1007/s11172-016-1433-9

Russian Chemical Bulletin, International Edition, Vol. 65, No. 5, pp. 1171—1177, May, 2016
1171
Synthesis and structure of bischelate gallium complexes
(dppꢀbian)Ga(acac) and (dppꢀbian)Ga(2,2´ꢀbipy)
(dppꢀbian is 1,2ꢀbis[(2,6ꢀdiisopropylphenyl)imino]acenaphthene)*
V. A. Dodonov, A. A. Skatova, A. V. Cherkasov, and I. L. Fedushkin
G. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences,
49 ul. Tropinina, 603950 Nizhny Novgorod, Russian Federation.
Fax: +7 (831) 462 7497. Eꢀmail: igorfed@iomc.ras.ru
A reaction of digallane [(dppꢀbian)Ga—Ga(dppꢀbian)] (1) (dppꢀbian is the 1,2ꢀbis[(2,6ꢀdiꢀ
isopropylphenyl)imino]acenaphthene) with one equivalent of I2 leads to oxidation of (dppꢀ
bian)2– in compound 1 to (dppꢀbian)– and gives [(dppꢀbian)GaI—GaI(dppꢀbian)] (2). In the
reaction of compound 2 with two equivalents of (acac)Na, not only exchange of the iodide and
acetylacetonate ions takes place, but also a transfer of electrons from the metal—metal bond to
dppꢀbian with the formation of the complex [(dppꢀbian)Ga(acac)] (3), in which the dppꢀbian
ligand is a dianion. A reaction of digallane 1 with 2,2´ꢀbipyridyl at 200 °C in toluene in a sealed
tube leads to the reduction of 2,2´ꢀbipyridyl and gives the complex [(dppꢀbian)Ga(bipy)] (4),
which contains two different chelate redoxꢀactive ligands. The new compounds were characꢀ
terized by IR (3, 4), NMR (3), and ESR spectra (4), the structures of both derivatives were
established by Xꢀray diffraction.
Key words: gallium, chelate ligands, synthesis, structure.
Metal complexes with redoxꢀactive ligands are the most
dynamically developing area of coordination compounds
chemistry. Together with the acquiring new knowledge on
the nature of chemical bond, stability and dynamics of
molecular systems, the studies in this region allows one to
design compounds, which can be used as reagents and
catalysts in the synthesis of practically valuable organic
products. Nontransition metal complexes with redoxꢀacꢀ
tive 1,2ꢀbis[(2,6ꢀdiisopropylphenyl)imino]acenaphthene
(dppꢀbian) is the area of our scientific interests. Starting
from the year of 2003 until the present time, we syntheꢀ
sized hundreds of new dppꢀbianꢀderivatives of nontransition
metals. Their overwhelming majority contains a dppꢀbian
radical anion1—10 or dianion.11—14 The complexes conꢀ
taining a dppꢀbian dianion, demonstrate the reactivity unꢀ
usual for metal compounds. They are characterized by
different types of chemical transformations in the reacꢀ
tions with different substrate, but they also have a comꢀ
mon feature: the main rearrangement of electron structure
and spatial geometry is undergone not by the central metal
atom, but by the coordinated dppꢀbian ligand. Recently,
we have found an unusual effect of the suppression by the
dppꢀbian dianion of reactivity of other ligands at the metal
atom, for example, an alkyl group in organoaluminum
compounds. Thus, treatment of complex [(dppꢀbian)AlEt]
with diphenylacetylene15 or water16 leads to neither incorꢀ
poration of the alkyne into the aluminum—alkyl bond,
nor hydrolysis of this bond. Both reactions proceed readiꢀ
ly, but involve only the dppꢀbian ligand. One of the most
interesting types of chemical reactions of the considered
class of compounds is a reversible cycloaddition by galliꢀ
um17—19 and aluminum20 derivatives of different alkynes.
We observed this process for the first time in 2010 for
digallane [(dppꢀbian)Ga—Ga(dppꢀbian)] (1) (Scheme 1).
Scheme 1
Ar = 2,6ꢀPri2C6H3
R = H, R´ = H; R = Ph, R´ = H; R = Me, R´ = C(O)Me
* Dedicated to Academician of the Russian Academy of Sciences O. G. Sinyashin on the occasion of his 60th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1171—1177, May, 2016.
1066ꢀ5285/16/6505ꢀ1171 © 2016 Springer Science+Business Media, Inc.

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Dodonov et al.
The process resembles the coordination step of unsaturatꢀ
ed substrates by transition metal ions and, probably, plays
a key role in the hydroamination reactions of phenylacetylꢀ
ene with aromatic amines catalyzed by digallane 1.17,18,21
Recently, we have shown19 that the catalytic activity
of some mononuclear gallium complexes with a dppꢀbian
dianion, for example, dithiocarbamate derivative [(dppꢀ
bian)Ga(S2CNMe2)] in the hydroamination reactions of
phenylacetylene is considerably lower than the activity
of digallane 1. Moreover, some mononuclear gallium
dppꢀbian derivatives do not form cycloadducts with alkynes
at all. Thus, the reaction of cyclopentadienyl derivative
[(dppꢀbian)Ga(C5H4CH2CH2NMe2)] with PhC≡CH leads
to acetylide [(dppꢀbian)Ga(C≡CPh)2] (see Ref. 19), in
which the dppꢀbian ligand is a radical anion. In order to
acquire new information on reactivity of gallium comꢀ
plexes containing a dppꢀbian dianion, we decided to synꢀ
thesize compound, which contain other chelating ligands
together with the dppꢀbian dianion, namely, acetylacetoꢀ
nate and 2,2´ꢀbipyridyl ones. In the present work, we synꢀ
thesized new compounds [(dppꢀbian)Ga(acac)] (3) and
[(dppꢀbian)Ga(bipy)] (4), established their structure by
Xꢀray diffraction, and carried out reactions of these comꢀ
pounds with some alkynes.
acetylacetonate (Scheme 2). A conversion of digallane 1
through compound 2 to product 3 is accompanied by the
change in color of solutions in the following order blue—
brown—blue. The product 3 was isolated from benzene as
dark blue crystals (30%).
Scheme 2
Results and Discussion
Synthesis and characterization of compounds [(dppꢀ
bian)Ga(acac)] (3) and [(dppꢀbian)Ga(2,2´ꢀbipy)] (4). The
reaction of digallane 1 with acetylacetone (acacH) does
not give a mixed dppꢀbian/acac gallium derivative, but
leads to the protonation of the dppꢀbian ligand and liberaꢀ
tion of diamine (dppꢀbian)H2. The target compound
[(dppꢀbian)Ga(acac)] (3) was obtained by the exchange
reaction of digallane [(dppꢀbian)GaI—GaI(dppꢀbian)]22 (2)
(prepared in situ from digallane 1 and iodine) with sodium
Ar = 2,6ꢀPri2C6H3
The dppꢀbian dianion in compound 3 has two mirror
planes, one of which coincide with the plane of the acetylꢀ
acetonate ligand and is orthogonal to the second mirror
plane lying in the plane of the fiveꢀmembered metalloꢀ
cycle. This is the reason that the 1H NMR spectrum (Fig. 1)
8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5
δ
Fig. 1. The 1H NMR spectrum of complex 3 (200 MHz, THFꢀd8, 298 К).

Gallium complexes with diimine chelating ligands
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 5, May, 2016
1173
exhibits a small number of signals. The methyl protons of
the Pri group are found as two doublets at δ 1.19 (12 H)
and 1.07 (12 H). A signal at δ 2.10 (6 H) is attributed to the
methyl protons of the acetylacetonate ligand, whereas
a signal at δ 5.82 (1 H) belongd to its methine proton.
A septet at δ 3.57 (4 H) is related to the methine protons of
the Pri groups. The protons of the naphthalene moiety of
the dppꢀbian dianion, as well as the protons of benzene
containing in the crystal cell, are found as the signals in
the range δ 7.23—5.86.
The addition of phenylacetylene to a solution of comꢀ
plex 3 leads to the change of the solution color from blue
to brown similar to that observed in the reaction of phenyꢀ
lacetylene with digallane 1. However, the Xꢀray diffracꢀ
tion data showed that the light brown crystals of the reacꢀ
tion product isolated from the ether solution are an adduct
between phenylacetylene and digallane 1. It is probable
that compound 3 is inert toward phenylacetylene. We suggest
that in the solution, compound 3 can give 1,1,2,2ꢀtetraꢀ
acetylethane and digallane 1, which is the compound to
react with phenylacetylene forming the known cycloadduct
(Scheme 3). Note that 1,1,2,2ꢀtetraacetylethane can be
obtained by the reaction of Na(acac) with iodine.23
giving complex [(dppꢀbian)Ga(bipy)] (4) (Scheme 4). The
reaction process includes the reduction of 2,2´ꢀbipyridyl
with electrons of the gallium—gallium bond, leaving the
dppꢀbian ligand as a dianion. Compound 4 was isolated
from ether as green needleꢀlike crystals in 37% yield and is
a rare example of the nontransition metal complex which
contains two different redoxꢀactive ligands. The presence
in compound 4 of 2,2´ꢀbipyridyl radical anion substantiꢀ
ates the appearance in the solution of this derivative of an
ESR signal (Fig. 2), a complex hyperfine structure (HFS)
of which complicates its interpretation. However, a genꢀ
eral pattern of the spectrum allows us to suggest that its
HFS is determined by the interaction of the unpaired elecꢀ
tron with magnetic gallium nuclei, as well as two nitrogen
atoms and four pairs of hydrogen atoms of the bipy ligand.
Scheme 4
Scheme 3
Ar = 2,6ꢀPri2C6H3
i. Toluene, 200 °C.
Molecular structures of compounds 3 and 4. Molecular
structures of complexes 3 and 4 were established by single
crystal Xꢀray diffraction analysis and are shown in Figs 3
and 4, respectively. Both compounds are monomeric comꢀ
plexes of tervalent gallium and contain only bidentate
ligands symmetrically chelating the metal atoms. A disꢀ
tortion of coordination surrounding of gallium atoms in
complexes 3 and 4 from the ideal tetrahedron is due to
5 mT
Ar = 2,6ꢀPri2C6H3
Under drastic conditions (200 °C, a sealed tube) digalꢀ
lane 1 in the toluene solution reacts with 2,2´ꢀbipyridyl
Fig. 2. The ESR spectrum of compound 4 (toluene, 297 К).

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Dodonov et al.
O(1)
N(1)
С(1)
С(2)
N(2)
С(1)
С(41)
N(3)
С(2)
Ga(1)
N(1)
Ga(1)
N(2)
N(4)
O(2)
С(42)
Fig. 4. Molecular structure of 4. Thermal ellipsoids drawn at
50% probability level. Hydrogen atoms are omitted.
Fig. 3. Molecular structure of complex 3. Thermal ellipsoids
drawn at 50% probability level. Hydrogen atoms are omitted.
a relatively small bond angles in the chelate fragments. In
compound 3, the angle between the planes of the dppꢀbian
and acac ligands is 85.4°. The Ga(1)—O(1) and Ga(1)—O(2)
distances (1.8894(11) and 1.8803(11) Å, respectively) in
compound 3 (Table 1) are close to the corresponding
values in the tetrahedral complex [(acac)Ga(Me)Cl]24
(1.901(7) and 1.878(7) Å), but are shorter than in the
hexacoordinated derivative [(acac)3Ga]25 (av. 1.952 Å).
The O(1)—Ga(1)—O(2) angle in complex 3 (96.01(5)°) is
close to the corresponding angle in [(acac)Ga(Me)Cl]24
(96.3(3)°), but is larger than an average value of the
O—Ga—O angles in [(acac)3Ga]25 (91.3(2)°).
tween two pyridyl rings is an indicative factor. For this
bond, the LUMO of 2,2´ꢀbipyridyl is a bonding one.
Therefore, a shortening of the central carbon—carbon bond
in 2,2´ꢀbipyridyl should occur upon occupation of the
LUMO. The C(41)—C(42) bond in complex 4 (1.423(5) Å)
is shorter as compared to the corresponding bond in the
free 2,2´ꢀbipyridyl (1.49 Å),30 but longer than the central
bond in the bipy ligand in the complexes [(bipy)Yb(thf)2]3
(1.41 Å)31 and [Na2(bipy)(dme)2]∞ (1.39 Å)32 containing
a bipy dianion. At the same time, the distance C(41)—C(42)
in complex 4 is comparable with the similar distances in comꢀ
The geometry of the gallene fragment C2N2Ga in
compound 3 (Ga(1)—N(1) 1.8721(13), Ga(1)—N(2)
1.8744(13), N(1)—C(1) 1.404(2), N(2)—C(2) 1.398(2),
and C(1)–C(2) 1.373(2) Å) is close to that of the correꢀ
sponding fragment in the starting digallane 1 (Ga(1)—N(1)
1.862(2), Ga(1)—N(2) 1.858(2), N(1)—C(1) 1.393(3),
N(2)—C(2) 1.389(3), and C(1)—C(2) 1.375(3) Å),26 that
confirms the dianionic state of the dppꢀbian ligand in
compound 3.
In the molecule of complex 4 (see Fig. 4, Table 2), the
angle between the planes of two N,N ligands is 86.0°. The
Ga—N(bipy) distance in compound 4 (Ga(1)—N(3) 1.945(2)
and Ga(1)—N(4) 1.958(2) Å) is noticeably shorter than
the corresponding distances in the following compounds:
[Ga(bipy)3]I3 (av. 2.068 Å),27 [Cp*(OC)2Fe][μꢀGa(bipy)]ꢀ
[Fe(CO)4] (av. 2.124 Å),28 and [GaCl2(Me2ꢀbpy)2](ClO4)
(av. 2.088 Å).29 This, apparently, reflects a stronger bindꢀ
ing of the gallium atom with the anionic bipy ligand in
complex 4 as compared to the interaction of gallium with
neutral 2,2´ꢀbipyridyl in the three complexes listed.
The alternation of bond distances in the bipy ligand,
together with the ESR spectroscopy data for complex 4,
indicate an anionic character of the bipy ligand in this
compound. In this sense, the carbon—carbon bond beꢀ
Table 1. Selected bond distances (d) and
bond angles (ω) in compound 3
Parameter
Bond
Value
d/Å
Ga(1)—N(1)
Ga(1)—N(2)
Ga(1)—O(2)
Ga(1)—O(1)
O(1)—C(38)
O(2)—C(40)
C(38)—C(39)
C(39)—C(40)
N(1)—C(1)
N(2)—C(2)
C(1)—C(2)
1.8721(13)
1.8744(13)
1.8803(11)
1.8894(11)
1.291(2)
1.285(2)
1.385(2)
1.392(2)
1.404(2)
1.398(2)
1.373(2)
Angle
ω/deg
N(1)—Ga(1)—N(2)
N(1)—Ga(1)—O(2)
N(2)—Ga(1)—O(2)
O(2)—Ga(1)—O(1)
C(1)—N(1)—Ga(1)
C(1)—C(2)—N(2)
93.06(5)
119.26(5)
116.58(5)
96.01(5)
104.76(9)
118.87(14)

Gallium complexes with diimine chelating ligands
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 5, May, 2016
1175
Table 2. Selected bond distances (d) and
bond angles (ω) in compound 4
Experimental
Compounds 1—4, as well as adduct 1•2PhC≡CH are sensiꢀ
tive to oxygen and air moisture, therefore all the manipulations
with them were carried out in vacuo using Schlenk technique.
Melting points of synthesized compounds were determined in
sealed evacuated capillaries. Toluene, diethyl ether, benzene,
THFꢀd8 were dried and stored over sodium benzophenone. IR
spectra (4000—400 cm–1) were obtained on a FSMꢀ1201 spectroꢀ
meter. To register the IR spectra, a suspension of a compound in
Nujol was prepared. 1H NMR spectra were recorded on a Bruker
DPXꢀ200 spectrometer (200 MHz). ESR spectra were obtained
on a Bruker ER 200 DꢀSRC spectrometer equipped with an ER
4105 DR double resonator (9.5 GHz) and an ER 4111 VT
thermocontroller. The gꢀfactor was determined using diphenylꢀ
picrylhydrazyl (DPPH, g = 2.0037) as a standard. 1,2ꢀBis[(2,6ꢀ
diisopropylphenyl)imino]acenaphthene (dppꢀbian) was obtained
by the condensation of acenaphthenequinone and 2,6ꢀdiisoꢀ
propylaniline in acetonitrile in the presence of a catalytic amount
of acetic acid. Digallane 1 was obtained by the reflux of a soluꢀ
tion of dppꢀbian in toluene (50 mL) with an excess of gallium
metall in an evacuated tube at 120 °C for 12 h (see Ref. 26).
A dark blue solution of digallane 1 was decanted from the excess
of gallium and used in further synthesis without isolation. Acetylꢀ
acetone and 2,2´ꢀbipyridine were purchased from Aldrich and
before use were distilled and sublimed, respectively. The proꢀ
duct yields indicated in description of the syntheses were calcuꢀ
lated on the amount of starting dppꢀbian.
Parameter
Bond
Value
d/Å
Ga(1)—N(1)
Ga(1)—N(2)
Ga(1)—N(3)
Ga(1)—N(4)
C(1)—C(2)
N(1)—C(1)
N(2)—C(2)
N(3)—C(41)
N(4)—C(42)
C(41)—C(42)
1.880(2)
1.887(2)
1.945(2)
1.958(2)
1.372(4)
1.398(3)
1.392(3)
1.393(4)
1.374(4)
1.423(5)
Angle
ω/ deg
N(1)—Ga(1)—N(2)
N(1)—Ga(1)—N(3)
N(2)—Ga(1)—N(3)
N(1)—Ga(1)—N(4)
N(2)—Ga(1)—N(4)
N(3)—Ga(1)—N(4)
C(1)—N(1)—Ga(1)
C(1)—C(2)—N(2)
90.89(10)
123.12(11)
126.28(10)
120.43(10)
115.63(11)
83.79(11)
106.6(2)
118.5(2)
1,2ꢀBis[(2,6ꢀdiisopropylphenyl)imino]acenaphthenidegalliꢀ
umacetylacetonate, [(dppꢀbian)Ga(acac)] (3). Iodine (0.13 g,
0.5 mmol) was added to a solution of complex 1 (prepared in situ
from diimine dppꢀbian (0.5 g, 1 mmol)) in toluene (50 mL). The
solution rapidly acquired a brown color and a finely crystalline
brickꢀred precipitate of digallane 2 was formed. Then, sodium
acetylacetonate (0.12 g, 1 mmol) was added to the reaction mixꢀ
ture. The tube was sealed and the reaction mixture was exposed
to ultrasound at 80 °C for 30 min. The solution gradually recoꢀ
vered a blue color, and a white precipitate appeared instead of
brown. After filtration of the solution, the solvent was removed
in vacuo, the residue was dissolved in benzene. Blue crystals of
compound 3 were isolated from the concentrated solution. The
yield was 0.2 g (30%), m.p. 217 °C. Found (%): C, 76.11; H 6.85.
C47H53GaN2O2 (747.63). Calculated (%): C, 75.50; H, 7.15. IR
(Nujol), ν/cm–1: 1679 w, 1645 w, 1596 s, 1529 s, 1340 w, 1210 w,
1193 w, 1141 w, 1109 m, 1057 w, 1025 s, 924 s, 852 w, 834 w, 805 w,
785 w, 765 s, 681 s, 652 w, 623 w, 597 w, 518 m, 487 m. 1H NMR
(200 MHz, THFꢀd8, 20 °C), δ: 7.23—7.12 (m, 6 H, CHarom);
pounds containing a bipy radical anion: [LaI2(bipy)2(dme)]
(1.457(10) Å),33 [YbI(bipy)(dme)2] (1.419(14) Å),34 and
[{tBu(Ar)N}2U(bipy)2] (1.426 Å).35 The structure of the
gallene fragment C2N2Ga in complex 4 is similar to the
structure of the corresponding fragment in compound 3.
In conclusion, the reaction of digallane [(dppꢀbian)ꢀ
GaI—GaI(dppꢀbian)] (2) with sodium acetylacetonate
clearly demonstrates the nonꢀinnocent of the dppꢀbian
ligand in the processes seemingly affecting only the metal
atom. Thus, a replacement of one anionic ligand with
another in the reaction of digallane 2 with Na(acac) changꢀ
es a reducing potential of the metal center and causes an
intramolecular electron transfer from the metal to the dppꢀ
bian ligand, leading to the formation of compound 3. Using
reduction of 2,2´ꢀbipyridine with digallane 1, we for the
first time obtained structurally characterized gallium comꢀ
plex with the bipy radical anion, namely, compound [(dppꢀ
bian)Ga(bipy)] (4). In such nontransition metal complexes
which contain two different redoxꢀactive ligands, a reversꢀ
ible externallyꢀinduced intramolecular ligand—ligand
electron transfer can be theoretically possible, which would
lead to the appearance of redoxꢀisomeric molecules not
observed earlier in nontransition metals chemistry. Finally,
we showed that compound 3 is inert towards phenylacetylꢀ
ene. The formation of a known cycloadduct in this reacꢀ
tion allowed us to suggest that in solution compound 3
can undergo reductive elimination of diacetylmethyl radiꢀ
cal with the formation of digallane 1 active toward phenylꢀ
acetylene.
7.01 (d, 2 H, CHarom, J = 8.2 Hz); 6.78 (pseudoꢀt, 2 H, CHarom
,
J = 7.7 Hz); 5.86 (d, 2 H, CHarom, J = 6.8 Hz); 5.82 (s, 1 H,
CH acac); 3.57 (sept, 4 H, CH(CH3)2, J = 6.8 Hz); 2.10 (s, 6 H,
CH3 acac); 1.19 (d, 12 H, CH(CH3)2, J = 6.8 Hz); 1.07 (d, 12 H,
CH(CH3)2, J = 6.8 Hz).
Reaction of compound 3 with phenylacetylene. Phenylacetylꢀ
ene (0.1 g, 1 mmol) was added by condensation in vacuo to
a solution of compound 3 (prepared in situ from diimine dppꢀbian
(0.5 g, 1 mmol) according to the procedure described above) in
toluene (50 mL). The solution immediately turned its color to
brown. Upon heating in a water bath to ~100 °C, the solution
reacquired a blue color, whereas upon cooling to room temperaꢀ
ture the blue color turned to brown. The solvent from the reacꢀ
tion mixture was removed in vacuo at room temperature. The

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Dodonov et al.
Table 3. Crystallographic data, parameters of Xꢀray diffraction experiments and refinement for
compounds 3 and 4
Parameter
3•C6H6
4•OC4H10
Molecular formula
Molecular weight
C47H53GaN2O2
747.63
C50H58GaN4O
800.72
Crystal system
Space group
a/Å
b/Å
c/Å
α/ deg
Monoclinic
P2(1)/c
12.0092(8)
16.5924(7)
20.5764(14)
90.00
Orthorhombic
P2(1)2(1)2(1)
13.7661(4)
17.0080(4)
18.4626(5)
90.00
β/ deg
93.516(7)
90.00
4092.4(4)
4
1.213
0.711
90.00
90.00
4322.73(19)
4
γ/ deg
V/Å3
Z
dcalc/mg m–3
1.230
0.678
μ/mm–1
F(000)
1584
1700
Crystal size/mm3
Range of data collection, θ/deg
Indices of h, k, l regions
0.40×0.40×0.10
2.986—26.000
–14 ≤ h ≤ 14
–20 ≤ k ≤ 20
–25 ≤ l ≤ 25
0.80×0.40×0.40
3.024—25.996
–16 ≤ h ≤ 16
–20 ≤ k ≤ 20
–22 ≤ l ≤ 22
Number of reflections
observed
independent
61314
8036
68433
8453
Rint
GOOF (F2)
0.0619
1.026
0.0543
1.091
R1/wR2 (I > 2σ(I))
R1/wR2 (for all reflections)
Residual electron density/e Å–3
0.0364/0.0797
0.0517/0.0842
0.445/–0.343
0.0310/0.0732
0.0333/0.0742
0.642/–0.253
residue was dissolved in diethyl ether. Light brown crystals of
compound 1•2PhC≡CH were isolated from a concentrated soluꢀ
tion. The yield was 0.26 g (38%). 1H NMR spectrum of the
product in C6D6 agrees with the spectrum described in the
literature.12 Apart from that, the formation of compound
1•2PhC≡CH was confirmed by Xꢀray diffraction. The crystals of
derivative 1•2PhC≡CH obtained by us differ from the crystals
described in the literature only by the solvent molecules (diethyl
ether instead of 1,2ꢀdimethoxyethane).
1,2ꢀBis[(2,6ꢀdiisopropylphenyl)imino]acenaphthenidegalliꢀ
umbipyridinate, [(dppꢀbian)Ga(bipy)] (4). 2,2´ꢀBipyridyl (0.62 g,
4 mmol) was added to a solution of complex 1 (prepared in situ
from diimine dppꢀbian (0.5 g, 1 mmol)) in toluene (50 mL). The
tube was sealed and heated in an oil bath at 200 °C for 15 min.
The color of the solution turned to green. After cooling the
reaction mixture to room temperature, toluene was removed
in vacuo, the residue was dissolved in diethyl ether and concenꢀ
trated to ~20 mL. After some time, green needleꢀlike crystals of
compound 4 (0.29 g, 37%) were isolated from the concentꢀ
rated solution, m.p. >260 °C. Found (%): C, 75.91; H, 7.85.
C50H58GaN4O (800.72). Calculated (%): C, 75.00; H, 7.30. IR
(Nujol), ν/cm–1: 1928 w, 1879 w, 1792 w, 1665 w, 1615 w, 1560 s,
1523 s, 1503 s, 1493 m, 1343 s, 1323 w, 1265 m, 1225 m, 1181 w,
1149 m, 1141 m, 1109 m, 1060 w, 1028 s, 961 s, 929 w, 912 w,
811 s, 767 s, 681 w, 669 m, 652 w, 623 w, 521 w, 466 w.
Xꢀray diffraction studies of compounds 3 and 4 were carried
out on a Agilent Xcalibur diffractometer (ωꢀscan technique,
MoꢀКα radiation, λ = 0.71073 Å, T = 100 K). Both structures were
solved by direct method and refined by the fullꢀmatrix least
squares method on F2 in anisotropic approximation for nonꢀ
hkl
hydrogen atoms. Hydrogen atoms were placed in geometrically
calculated positions and refined isotropically. The calculations
and correction for absorption were carried out using the CrysAlis
PRO36 and SHELX37 software packages. Crystallographic data
and parameters of Xꢀray diffraction experiments are given in
Table 3. The structures were deposited with the Cambridge Crysꢀ
tallographic Data Center (CCDC 1446788 (3) and 1446789 (4))
and are available at ccdc.cam.ac.uk/getstructures.
This work was financially supported by the Russian
Science Foundation (Project No. 14ꢀ13ꢀ01063).
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Received January 12, 2016;
in revised form January 20, 2016