Protonation of magnesium and sodium complexes containing dianionic diimine ligands. Molecular structures of 1,2-bis{(2,6-diisopropylphenyl)imino} acenaphthene (dpp-BIAN), [(dph-BIAN)H2(Et2O)], and [(dpp-BIAN)HNa(Et2O)]

Article abstract of DOI:10.1007/s11172-005-0185-8

Hydrolysis of magnesium complexes containing the dianionic acenaphthenediimine ligands, (dpp-BIAN)Mg(thf)₃ (1), (dph-BIAN)Mg(thf)₃ (2), and (dtb-BIAN)Mg(thf)₂ (3) (dpp-BIAN is 1,2-bis{ (2,6-diisopropylphenyl)imino}acenapht

Full text of DOI:10.1007/s11172-005-0185-8

2744
Russian Chemical Bulletin, International Edition, Vol. 53, No. 12, pp. 2744—2750, December, 2004
Protonation of magnesium and sodium complexes
containing dianionic diimine ligands. Molecular structures of
1
,2ꢀbis{(2,6ꢀdiisopropylphenyl)imino}acenaphthene (dppꢀBIAN),
(dphꢀBIAN)H (Et O)], and [(dppꢀBIAN)HNa(Et O)]
[
2
2
2
I. L. Fedushkin,aꢀ V. A. Chudakova, G. K. Fukin, S. Dechert, M. Hummert, and H. Schumann
a
a
b
b
b
aG. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences,
4
9 ul. Tropinina, 603950 Nizhnii Novgorod, Russian Federation.
Fax: +7 (831 2) 12 7497. Eꢀmail: igorfed@imoc.sinn.ru
b
Technical University of Berlin,
1
35 Strasse des 17 Juni, Dꢀ10623 Berlin, Germany.*
Fax: +49 (30) 3142 2168
Hydrolysis of magnesium complexes containing the dianionic acenaphthenediimine ligands,
(
dppꢀBIAN)Mg(thf) (1), (dphꢀBIAN)Mg(thf) (2), and (dtbꢀBIAN)Mg(thf) (3) (dppꢀBIAN
3
3
2
is 1,2ꢀbis{(2,6ꢀdiisopropylphenyl)imino}acenaphthene; dphꢀBIAN is 1,2ꢀbis{(2ꢀdipheꢀ
nyl)imino}acenaphthene; dtbꢀBIAN is 1,2ꢀbis{(2,5ꢀdiꢀtertꢀbutylphenyl)imino}acenaphthene),
affords the corresponding diamines (dppꢀBIAN)H2 (4), (dphꢀBIAN)H (Et O) (5), and
2
2
(
dtbꢀBIAN)H (6). Compounds 4 and 5 were isolated in the crystalline state and characterized
2
1
by UV—Vis, IR, and H NMR spectroscopy. Partial hydrolysis of (dppꢀBIAN)Na (Et O)
2
2
3
gave the crystalline (dppꢀBIAN)HNa(Et O) complex (7), which was also characterized by
2
2
spectroscopic methods. The structures of compounds 5 and 7 and free diimine dppꢀBIAN were
established by Xꢀray diffraction analysis.
Key words: magnesium, sodium, diimine ligands, dianion, protonation, acenaphthyleneꢀ
1
,2ꢀdiamine.
Recently,1,2 we have synthesized alkali and alkalineꢀ
earth metal complexes with various reduced forms of
,2ꢀbis[(2,6ꢀdiisopropylphenyl)imino]acenaphthene
dppꢀBIAN). In solvating solvents, alkali metals (Li, Na)
compound 1 reduces diphenyl ketone, resulting in oxidaꢀ
tion of the dppꢀBIAN dication to the radical anion and
1
(
the formation of pinacolate [(dppꢀBIAN)Mg(thf)] [µꢀ
2
O C Ph ], whereas the reaction of 1 with 9(10H )ꢀanthraꢀ
2
2
4
successively reduce dppꢀBIAN to the monoꢀ, diꢀ, triꢀ,
cenone is accompanied by deprotonation of the phenol
tautomer to form the anthrylꢀ9ꢀoxy derivative
and tetraanions M+n(dppꢀBIAN) (M = Li, Na; n = 1,
n–
5
2
, 3, or 4). Reduction of dppꢀBIAN with metallic magꢀ
(dppꢀBIAN)Mg(OC H )(thf) . The reactions of comꢀ
14
9
2
nesium or calcium in THF affords exclusively comꢀ
plexes with the dppꢀBIAN dianion of composition
plex 1 with halogenꢀcontaining inorganic (CuCl, SiCl , I )
4 2
and organic (Ph SnCl, 1,2ꢀdibromoꢀ1,2ꢀdiphenylethane)
3
2
–
2+
(
dppꢀBIAN)
M
(thf)n (M = Mg, n = 3; M = Ca,
compounds also lead to oxidation of the dppꢀBIAN
dianion to the radical anion and the formation of the
3
4
n = 4). We have also synthesized two new ligands of this
type, viz., 1,2ꢀbis[(2,5ꢀdiꢀtertꢀbutylphenyl)imino]aceꢀ
naphthene (dtbꢀBIAN) and 1,2ꢀbis[(2ꢀdiphenyl)imiꢀ
no]acenaphthene (dphꢀBIAN), as well as their magneꢀ
unsymmetrical [(dppꢀBIAN)Mg(µꢀX)(thf)] (X = Cl, Br)
2
6
and (dppꢀBIAN)MgI(DME) complexes. The reactions
of complex 1 with Me SiCl and Me NCH CH Cl reꢀ
3
2
2
2
2
–
2+
sium and calcium derivatives (dtbꢀBIAN) Mg (thf)2
and (dphꢀBIAN)2
M = Ca, L = thf, n = 3).
Investigation of
dppꢀBIAN)Mg(thf) complex (1) with a series of organic
–
M
2+
Ln (M = Mg, L = DME, n = 2;
the
reactions
of
the
(
3
compounds revealed their specific reactivity. For example,
*
Institute für Chemie der Technischen Universität Berlin,
Straße der 17 Juni 135, Dꢀ10623 Berlin, Germany.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2634—2640, December, 2004.
066ꢀ5285/04/5312ꢀ2744 © 2004 Springer Science+Business Media, Inc.
1

Protonation of Mg and Na diimine complexes
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 12, December, 2004 2745
sulted in the addition of the alkyl group to the imine
carbon atom of the ligand, which has not been observed
earlier for diimine derivatives of mainꢀgroup metals. The
water vapor, the solutions of complexes 1—3 turned
violetꢀred. In the first two cases, acenaphthyleneꢀ
1,2ꢀ(N,N´ꢀaryl)diamines, viz., (dppꢀBIAN)H (4) and
2
reaction with Me SiCl is accompanied by the THF ring
(dphꢀBIAN)H (Et O) (5), respectively, were obtained afꢀ
3
2
2
opening.
ter removal of the solvent and extraction of organic prodꢀ
ucts with hexane and diethyl ether (Scheme 1).
The reactions of complex 1 with various C—Hꢀ,
N—Hꢀ, and O—Hꢀacids proceed in an unusual fashion.
Unlike 9(10H)ꢀanthracenone, these compounds are not
deprotonated with complex 1; instead, they are bound to
this complex. For example, the reaction of complex 1
with phenylacetylene affords the phenylethynyl derivative
Scheme 1
[
dppꢀBIAN(H)]Mg(C≡CPh)(thf) . However, the latter
2
eliminates the hydrogen atom upon the insertion of dipheꢀ
nyl ketone, which is accompanied by oxidation of the
dppꢀBIAN ligand to the radical anion and the formation
7
of alkoxide (dppꢀBIAN)Mg[OC(Ph )C≡CPh](thf).
2
i. H O, 1) THF, 2) hexane; ii. H O, 1) THF, 2) Et O.
2
2
2
As part of our continuing studies on protonation of
metal complexes containing the dianionic dppꢀBIAN
ligand, we investigated hydrolysis of sodium and magneꢀ
sium derivatives. Hydrolysis of magnesium complexes was
found to produce the corresponding acenaphthyleneꢀ1,2ꢀ
High solubility of diamine (dtbꢀBIAN)H (6) that
2
formed upon hydrolysis of complex 3 did not allow us to
1
isolate it in the crystalline state. However, the H NMR
spectrum of the reaction mixture confirms the presence of
compound 6. The spectrum of a solution in THFꢀd shows
8
(
N,N´ꢀaryl)diamines regardless of the amount of H O
2
two singlets at δ 1.03 and 1.31 assigned to the protons of
the Me groups of the tertꢀbutyl substituents. The signal for
the proton of the amino group appears as a singlet at δ 5.77.
Compounds 4 and 5 were crystallized from hexane
and diethyl ether as darkꢀred needleꢀlike and prismatic
crystals, respectively. Unexpectedly, waterꢀstable diꢀ
amines 4 and 5 in solutions were virtually immediately
oxidized with atmospheric oxygen to give the starting
used in the reaction, whereas the reaction of the sodium
complex with an equimolar amount of H O resulted in
2
protonation of only one nitrogen atom.
Results and Discussion
Hydrolysis of magnesium acenaphthenediimine comꢀ
plexes. The starting solutions of the (dppꢀBIAN)Mg(thf)3
diimines. In the IR spectra of diamines 4 and 5, the N—H
stretching bands are observed at 3370 and 3350 cm–
1
,
(
(
1), (dphꢀBIAN)Mg(thf) (2), and (dtbꢀBIAN)Mg(thf)
3) complexes were prepared in situ by reducing the corꢀ
n
2
respectively. As in dppꢀBIAN, there is no free rotation of
the Ph rings about the N—Cipso bond in compound 4 due
to steric effects, which is reflected in the presence of two
responding diimine (1 mmol) in THF with an excess of
magnesium.3 Since it was difficult to add a strictly
stoichiometric amount of liquid water, hydrolysis was carꢀ
ried out using slow diffusion by delivering water vapor to a
solution of the complex under vacuum. The completeꢀ
ness of the reaction was monitored by the change in the
color of the solution of the complex. When exposed to
,4
i
different signals for the Me protons of the Pr substituents
1
in the H NMR spectrum (doublets at δ 1.26 and 1.19).
i
Four equivalent methine protons of the Pr groups are
1
observed as a septet at δ 3.63. In the H NMR spectrum of
compound 5, the signals for nine of twelve aromatic proꢀ

2746
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 12, December, 2004
Fedushkin et al.
tons lie in a narrow region, which hinders their assignꢀ
ment. Three other signals are observed as a doublet of
triplets and two triplets of doublets at δ 7.48, 7.06,
Compound 7 is an intermediate in the transformation
of (dppꢀBIAN)Na (Et O) into diamine 4. In the IR specꢀ
2
2
3
trum of complex 7, a pronounced N—H stretching band
1
1
and 6.87, respectively. In the H NMR spectra of comꢀ
is absent. In the H NMR spectra of compound 7 both in
pounds 4 and 5 (both in C D ), the signals for the N—H
THFꢀd and C D , all signals are strongly broadened,
6
6
8
6
6
protons appear as singlets at δ 5.08 and 5.65, respectively.
Compared to the starting diimines, compounds 4 and 5
are more brightly colored. Presumably, their electronic
structures are similar to metal complexes, such as
which, in our opinion, indicates that dynamic processes
occur in solution. Slow (on the NMR time scale) proton
migration between two nitrogen atoms can be one of such
processes. We have observed an analogous spectral patꢀ
1
,2
3
7
(
dppꢀBIAN)Na (Et O)
and (dppꢀBIAN)Mg(thf)3.
In the visible region of the spectrum of the
dppꢀBIAN)Na (Et O) complex, the absorption band has
tern for [dppꢀBIAN(H)]Mg(C≡CPh)(thf) .
2
2
3
2
1
In the H NMR spectrum of compound 7 in C D ,
6
6
i
(
the Me protons of the Pr substituents appear as one broad
signal at δ 1.2, and the signals for the methine protons of
these substituents are observed as broad signals at δ 3.85
and 3.45. The signals for the aromatic protons are also
strongly broadened and are observed at δ 7.5—6.0. Alꢀ
though the spectrum is poorly informative, it has a broad
signal for the proton of the amino group at δ 4.98. In the
2
2
3
2
a maximum at 640 nm, whereas the spectra of comꢀ
pounds 4 and 5 in Et O show bands with maxima at 536
2
and 500 nm, respectively. In a THF solution, the maxiꢀ
mum of the absorption band of compound 4 is observed at
5
50 nm. In THF and Et O solutions, compound 4, apꢀ
2
parently, forms complexes with these ethers through
N—H...Osolv hydrogen bonds (solv is the solvent).
Protonation of the magnesium derivatives with water
differs from their protonation with C—Hꢀ, N—Hꢀ,
and O—Hꢀacids. For example, the reaction of
spectrum in THFꢀd , the corresponding signal has virtuꢀ
8
ally the same chemical shift (δ 5.05). The absorption band
in the UV—Vis absorption spectrum with a maximum at
625 nm corresponds to the blue color of complex 7 in a
diethyl ether solution.
(
dppꢀBIAN)Mg(thf)3 with even a fivefold excess of
phenylacetylene is not accompanied by protonation of
the second nitrogen atom and gives the phenylethynyl
Molecular structures of compounds 5, 7, and
dppꢀBIAN. In spite of the fact that dppꢀBIAN is widely
8
—12
derivative [dppꢀBIAN(H)]Mg(C≡CPh)(thf) as the final
used in transition metal chemistry,
the molecular
2
product.7
structure of the free ligand has not been determined earꢀ
lier. Crystals of dppꢀBIAN suitable for Xꢀray diffraction
analysis were grown from toluene. The structures of comꢀ
pounds 5, 7, and dppꢀBIAN were established by Xꢀray
diffraction analysis and are shown in Figs 1, 2, and 3,
respectively. The crystallographic data, details of Xꢀray
data collection, and characteristics of structure refineꢀ
ment are given in Table 1. Selected bond lengths and
bond angles for the structures of 5, 7, and dppꢀBIAN are
listed in Table 2.
Hydrolysis of (dppꢀBIAN)Na (Et O) . Hydrolysis of
2
2
3
the (dppꢀBIAN)Na (Et O) compound, which was preꢀ
2
2
3
pared in situ by reducing dppꢀBIAN with two equivalents
of sodium in diethyl ether, with an excess of water afꢀ
forded diamine 4. However, slow diffusion of water vapor
into a solution of the sodium complex initially led to a
change in the color of the solution to darkꢀblue, and only
further addition of H O resulted in the violetꢀred color of
2
the solution. The darkꢀblue ethereal solution was conꢀ
centrated to give the (dppꢀBIAN)HNa(Et O) compound
2
2
(
7) as darkꢀblue crystals sensitive to atmospheric oxygen
and moisture (Scheme 2).
Scheme 2
O
H(1)
N(1)
H(2)
N(2)
C(1)
C(2)
C(13)
C(25)
Fig. 1. Molecular structure of (dphꢀBIAN)H (Et O) (5) with
2
2
displacement ellipsoids drawn at the 30% probability level. The
H atoms, except for those bound to the N atoms, are omitted.

Protonation of Mg and Na diimine complexes
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 12, December, 2004 2747
O(1)
H(1)
C(13)
C(8)
N(2) Na
C(2)
N(1)
C(8#)
C(1) C(1#)
N(1)
N(1#)
C(25)
C(1)
O(2)
Fig. 2. Molecular structure of (dppꢀBIAN)HNa(Et O) (7) with
displacement ellipsoids drawn at the 30% probability level. The
H atoms, except for H(1), are omitted.
Fig. 3. Molecular structure of dppꢀBIAN with displacement
ellipsoids drawn at the 30% probability level. The H atoms are
omitted.
2
2
It should be noted that the crystal structure of diamine
(see Fig. 1) contains the diethyl ether molecule coordiꢀ
nated to the H(1) and H(2) atoms of 5 through hydrogen
bonds. These H atoms were localized from difference
Fourier syntheses at the N(1) and N(2) atoms at distances
of 0.92(3) [N(1)] and 0.86(3) [N(2)] Å, respectively.
The H(1)—O and H(2)—O distances are 2.206(3) and
2.134(3) Å, respectively. The sums of the bond angles at
5
Table 1. Crystallographic data, characteristics of Xꢀray data collection, and details of strucꢀ
ture refinement for compounds 5, 7, and dppꢀBIAN
Parameter
5
7
dppꢀBIAN
Molecular formula
C H N O
C H N NaO
C H N2
4
0
36
2
44 61
2
2
36 40
Molecular weight
560.71
Monoclinic
173
672.94
Triclinic
500.70
Monoclinic
173
Crystal system
Temperature/K
Space group
a/Å
b/Å
c/Å
α/deg
β/deg
γ/deg
V/Å3
100
–
P2 /с
P1
C2/c
1
11.2028(1)
15.2839(1)
18.5180(1)
90
101.598(1)
90
3105.96(4)
4
1.199
10.5184(17)
13.792(2)
14.580(2)
79.307(3)
70.938(3)
89.168(3)
1962.0(6)
2
15.4976(7)
8.8279(4)
21.5282(11)
90
93.88
90
2938.6(2)
4
1.132
Z
–
3
d/g cm
µ/mm–1
1.139
0.078
0.071
0.065
F(000)
1192
732
1080
Crystal dimensions/mm
Scan range, θ/deg
Ranges of h, k, l indices
0.36×0.32×0.16
1.74—26.00
–13 ≤ h ≤ 12
0.40×0.40×0.10
1.50—25.00
–12 ≤ h ≤ 12
–16 ≤ k ≤ 16
–17 ≤ l ≤ 17
15188
0.52×0.31×0.18
1.90—25.00
–18 ≤ h ≤ 18
–6 ≤ k ≤ 10
–25 ≤ l ≤ 25
8543
–
18 ≤ k ≤ 18
–
22 ≤ l ≤ 19
19920
Number of observed reflections
Number of independent reflections
Rint
6052
0.0847
1.002
6866
0.0192
1.057
2586
0.0815
1.050
Goodnessꢀofꢀfit on F 2
R /wR (I > 2σ(I ))
0.0612/0.1127
0.0692/0.1853
0.0833/0.1945
0.944/–0.329
0.0759/0.1843
0.1334/0.2134
0.362/–0.263
1
2
R /wR (based on all parameters) 0.1207/0.1317
1
2
Residual electron
density/e Å–3, ρmax/ρmin
0.244/–0.288

2748
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 12, December, 2004
Fedushkin et al.
Table 2. Selected bond lengths (d) and bond angles (ω) in molꢀ
ecules 5, 7, and dppꢀBIAN
In complex 7 (see Fig. 2), the Na atom is bound to
two N atoms of the chelating amido/amino ligand and
lies virtually in the mean plane of the N(1)—C(1)—
C(2)—N(2) fragment (C(1)—C(2)—N(2)—Na(1) torsion
angle is 5.2°). The differences in the amido and amino
functions of two N atoms are manifested in the different
lengths of their bonds with the Na atom. The Na—N(1)
amide bond [2.3385(17) Å] is shorter than the Na—N(2)
coordination bond [2.4429(17) Å]. In the difference Fouꢀ
rier synthesis, the H(1) atom was revealed at a distance of
Parameter
Bond
5
7
dppꢀBIAN
d/Å
Na—N(1)
Na—N(2)
H(1)—N(2)
H(2)—N(2)
Na—O(1)
Na—O(2)
H(1)—O
H(2)—O
C(1)—N(1)
C(2)—N(2)
C(1)—C(2)
C(13)—N(1)
C(25)—N(2)
C(1)—N(1)
C(1#)—N(1#)
C(1)—C(1#)
C(2)—N(1)
C(2#)—N(1#)
—
—
0.92(3)
0.86(3)
—
2.3385(17)
2.4429(17)
1.04(3)
—
2.3694(15)
2.3080(15)
—
—
—
—
—
—
—
—
—
—
—
—
—
—
1
.04(3) Å from the N(2) atom, which is larger than the
N—H bond lengths in the structure of 5 [0.92(3) and
.86(3) Å]. Hence, it can be suggested that the interacꢀ
—
2.206(3)
2.134(3)
1.395(3)
1.400(3)
1.369(3)
1.400(3)
1.394(3)
—
0
—
1.347(2)
1.434(2)
1.395(3)
1.403(2)
1.433(2)
—
—
—
—
—
tion between the H(1) and N(2) atoms in molecule 7 is
more ionic than that in molecule 5. This is confirmed by
the absence of the N—H stretching band in the IR specꢀ
trum. Since the IR spectrum of compound 7 was recorded
at room temperature, it was worthwhile establishing the
structure of complex 7 and, primarily, determining the
position of the H atom at room temperature. Due to
1.282(4)
1.282(4)
1.534(6)
1.422(4)
1.422(4)
—
—
—
—
abnormally high thermal motion of the Et O molecules,
2
the quality of Xꢀray diffraction data at 293 K is noticeably
lower than that at 100 K. However, it should be noted that
the H atom at room temperature was localized at an even
larger distance from the N(2) atom (1.22(8) Å). The sums
of the bond angles at the N(1) (359.8°) and N(2) (342.2°)
atoms (see Table 1) show that the N(1) atom has a trigoꢀ
nalꢀplanar geometry, whereas the geometry of the enviꢀ
ronment about the N(2) atom is intermediate between
the trigonalꢀplanar and pyramidal (sum of the angles
is 328.0°).
The dppꢀBIAN molecule (see Fig. 3) is located on a
crystallographic twofold rotation axis passing along the
C—C bond between two sixꢀmembered rings of the naphꢀ
thalene fragment. The C(1)—N(1) and C(1#)—N(1#) disꢀ
tances [1.282(4) Å] correspond to the carbon—nitroꢀ
gen double bond, whereas the C(1)—C(1#) distance
[1.534(6) Å] is nearly equal to the length of the C—C
single bond.
Angle
ω/deg
C(1)—N(1)—C(13) 122.85(19)
C(1)—N(1)—H(1) 115.37(19)
C(13)—N(1)—H(1) 120.46(19)
C(2)—N(2)—C(25) 122.82(18)
C(2)—N(2)—H(2) 117.72(19)
C(25)—N(2)—H(2) 117.52(19)
120.18(14)
—
122.9(2)
—
—
—
117.08(13)
106.97(13)
—
76.48(6)
94.20(6)
110.14(11)
129.46(11)
104.80(11)
120.35(10)
122.9(2)
—
—
—
—
—
—
—
—
N(1)—Na(1)—N(2)
O(1)—Na(1)—O(2)
C(1)—N(1)—Na(1)
C(13)—N(1)—Na(1)
C(2)—N(2)—Na(1)
C(25)—N(2)—Na(1)
—
—
—
—
—
—
the nitrogen atoms [N(1), 358.7°; N(2), 358.1°] are only
slightly smaller than the sum of the angles for the ideal
trigonalꢀplanar environment (360°), which indicates that
the lone electron pairs of the N atoms are conjugated with
the πꢀsystem of the Ph rings. As a result of conjugation,
the H(1) and H(2) protons become more acidic, which is
favorable for strong hydrogen bonding with the O atom of
the ether molecule. Diamine 5 can exist as two isomers,
which differ in the mutual arrangement of the orthoꢀsubꢀ
stituents in the aniline fragments relative to the plane of
The C—N distances in molecule 5 [1.395(3) and
1.400(3) Å] are longer than those in the free diimines
4
dphꢀBIAN and dppꢀBIAN by ~0.13 Å and are close to
the corresponding distances in the (dphꢀBIAN)Ca(thf)
3
4
[1.421(11) and 1.405(11) Å] and (dppꢀBIAN)Na (Et O)
2
2
3
1
[1.387(4) and 1.386(4) Å] molecules. The C(1)—C(2)
bond in compound 5 is, on the contrary, shortened comꢀ
4
9
pared to those in dphꢀBIAN and dppꢀBIAN (its length
is 1.369(3) Å). The asymmetry of the structure of comꢀ
plex 7 is manifested in the difference in the C—N bond
lengths in the diimine fragment of the molecule. The
C(1)—N(1) bond [1.347(2) Å] is substantially shorter than
the C(2)—N(2) bond [1.434(2) Å], whose length is, in
turn, similar to the corresponding bond lengths in molꢀ
ecule 5. The C(1)—N(1) distance is comparable to
the C—N bond lengths in the sodium complex
acenaphthylene. Unlike the starting dphꢀBIAN compound
4
(
(
E,Zꢀanti isomer) and related germylene (dphꢀBIAN)Ge
E,Eꢀanti isomer),1 diamine 5 is the syn isomer. An analoꢀ
gous geometry of the ligand has been observed in the
3
4
(
dphꢀBIAN)Ca(thf) complex. In the biphenyl groups
3
bound to the N(1) and N(2) atoms, the Ph rings are
twisted with respect to each other by 59.6 and 44.5°, reꢀ
spectively.

Protonation of Mg and Na diimine complexes
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 12, December, 2004 2749
[
[
(dppꢀBIAN)Na]2 with the dppꢀBIAN radical anion
N(1)—C(1), 1.3239(18) Å; N(2)—C(2), 1.3326(19) Å].
turned violetꢀred. Volatile products were removed in vacuo, and
1
the product was dissolved in hexane and crystallized to prepare
compound 4 in a yield of 0.48 g (96%) as darkꢀred needleꢀlike
crystals, m.p. 143 °C. Found (%): C, 83.44; H, 7.72. C H N .
In all cases, reduction of the dppꢀBIAN radical anion
to the dianion leads to shortening of the C(1)—C(2)
bond. For example, the C(1)—C(2) bond length
in [(dppꢀBIAN)Na]2 is larger than that in
3
6
42
2
Calculated (%): C, 86.01; H, 8.42; N, 5.57. Reliable elemental
analysis data were not obtained because of high sensitivity of
–1
compound 4 to atmospheric oxygen and moisture. IR, ν/cm
:
(
dppꢀBIAN)Na (Et O) (1.446(2) and 1.402(4) Å, reꢀ
2 2 3
3370 w, 1570 v.s, 1330 m, 1255 m, 1200 w, 1100 m, 1050 w,
1025 w, 915 m, 800 s, 770 s, 750 v.s, 720 s. 1H NMR (200 MHz,
1
spectively). The C(1)—C(2) bond in compound 7, like
that in the BIAN dianion in the sodium complex, is short
C D , 20 °C), δ: 7.36—7.20 (m, 8 H); 7.01 (t, 2 H, J = 8.0 Hz);
6
6
(
1.395(3) Å).
6.57 (d, 2 H, J = 7.0); 5.08 (s, 2 H, NH); 3.63 (sept, 4 H, J =
6
.8 Hz); 1.26 and 1.19 (both d, 12 H each, J = 6.8 Hz).
To summarize, hydrolysis of the magnesium and soꢀ
N,N´ꢀBisꢀbiphenylꢀ2ꢀylacenaphthyleneꢀ1,2ꢀdiamine (5). Waꢀ
dium complexes containing the dianionic acenaphtheneꢀ
diimine ligands affords acenaphthyleneꢀ1,2ꢀbis(N,N´ꢀ
aryl)diamines. Spectroscopic and Xꢀray diffraction data
and the fact that these diamines are readily oxidized with
atmospheric oxygen suggest that they can formally be
considered as compounds of the dianions of the correꢀ
ter vapor was slowly supplied to a solution of complex 2, which
was prepared from dphꢀBIAN (0.49 g, 1.0 mmol) in THF, with
cooling (10—0 °C) until the solution turned darkꢀred. The solꢀ
vent was removed in vacuo, and diethyl ether (50 mL) was added
to the residue. The reaction product was extracted with diethyl
ether until the solution ceased to turn red. Compound 5 was
+
sponding BIAN ligands with two H cations. The latter,
isolated by crystallization from Et O as darkꢀred prismatic crysꢀ
2
unlike metal cations, do not form chelate rings, and are
located at the N atoms. Isolation of the partially protoꢀ
tals in a yield of 92% (0.51 g), m.p. 80 °C. Found (%): C, 85.42;
H, 6.32. C H N O. Calculated (%): C, 85.68; H, 6.47. IR,
40 36
2
–
1
ν/cm : 3350 m, 3315 m, 1600 s, 1505 s, 1490 s, 1430 s, 1360 m,
nated (dppꢀBIAN)HNa(Et O) complex (7) provides eviꢀ
2
1
8
300 m, 1280 s, 1230 w, 1150 m, 1100 s, 1035 w, 1005 w, 930 w,
50 w, 820 w, 785 s, 740 v.s, 700 s, 610 w, 535 s. H NMR
dence that there is a continuum of various dianionic forms
of the BIAN ligands. Diamines 4—6, like metal comꢀ
plexes with the BIAN dianions, can be used as reducing
agents in organic synthesis. Unlike metal complexes, these
compounds can serve as sources of H• rather than as
electron sources. Studies of the reactions of diamines 4—6
with organic compounds are presently underway.
1
(
200 MHz, C D , 20 °C), δ: 7.48 (dt, 2 H, J = 9.0 Hz, J =
6 6
3
1
.5 Hz); 7.40—7.12 (m, 18 H); 7.06 (td, 2 H, J = 8.0 Hz, J =
.5 Hz); 6.87 (td, 2 H, J = 7.2 Hz, J = 1.2 Hz); 5.65 (s, 2 H,
NH); 3.36 (q, 4 H, CH O, J = 7.0 Hz); 1.20 (t, 6 H, CH CH O,
2
3
2
J = 7.0 Hz).
N,N´ꢀBisꢀ(2,5ꢀdiꢀtertꢀbutylphenyl)acenaphthyleneꢀ1,2ꢀdiꢀ
amine (6). Water vapor was slowly supplied to a solution of
complex 3, which was prepared from dtbꢀBIAN (0.56 g,
Experimental
1
.0 mmol) in THF, with cooling (10—0 °C) until the solution
turned violetꢀred. The solvent was removed in vacuo, and diꢀ
ethyl ether (30 mL) was added to the residue. After centrifugaꢀ
tion, the solution was decanted from the precipitate, and an
aliquot of the solution (0.5 mL) was placed in an NMR tube.
Volatile products were removed from the main solution in vacuo.
Compound 6 was obtained as a darkꢀred oil in a yield of 0.55 g
Since all the aboveꢀmentioned compounds, except for
diimines dppꢀBIAN, dphꢀBIAN, and dtbꢀBIAN, are sensitive
to atmospheric oxygen and moisture, operations associated with
their synthesis, isolation, and identification were carried out
in vacuo using the Schlenk technique. Diimine dppꢀBIAN was
prepared by condensation of acenaphthenequinone with the corꢀ
responding aniline (both were purchased from Aldrich) in acꢀ
etonitrile.14 Complexes 1—3 were synthesized according to proꢀ
cedures described earlier.3 In all cases, solutions of complexes
1
(98%). H NMR (200 MHz, THFꢀd , 20 °C), δ: 7.43 (d, 2 H,
8
J = 8.3 Hz); 7.18 (t, 2 H, J = 6.8 Hz); 7.15 (d, 2 H, J = 2.0 Hz);
7.13 and 7.01 (both d, 2 H each, J = 6.8 Hz); 6.79 (dd, 2 H, J =
8.3 Hz, J = 2.0 Hz); 5.77 (s, 2 H); 1.31 and 1.03 (both s,
18 H each).
,4
1
—3 in THF were prepared from the corresponding diimine
(
1.0 mmol) and an excess of magnesium metal and were used in
Acenaphthyleneꢀ1ꢀ(2,6ꢀdiisopropylphenylamino)ꢀ2ꢀ(2,6ꢀdiꢀ
isopropylphenylamido)sodium diethyl etherate (7). Water vapor
was slowly supplied to a solution of the (dppꢀBIAN)Na (Et O)
3
hydrolysis in situ. Tetrahydrofuran, diethyl ether, and hexane
were dried, stored over sodium benzophenone ketyl, and disꢀ
tilled immediately before use. The yields of the products are
given with respect to the amount of diimine (1.0 mmol) used for
the synthesis of complexes 1—3. The IR spectra were recorded
on a Specord Mꢀ80 spectrometer (Nujol mulls). The NMR specꢀ
tra were measured on Bruker DPX 200 and Bruker ARX 400
spectrometers; the chemical shifts are given in the δ scale relaꢀ
tive to the chemical shifts of the residual protons of deuterated
solvents.
2
2
complex, which was prepared from dppꢀBIAN (0.5 g, 1.0 mmol)
and sodium (0.046 g, 2.0 mmol) in Et O (35 mL), with cooling
2
(10—0 °C) until the solution turned darkꢀblue. Then the soluꢀ
tion was separated from insoluble products by centrifugation
and decantation. Compound 7 was isolated from the concenꢀ
trated solution (15 mL) as large darkꢀblue prismatic crystals in a
yield of 0.37 g (92%), m.p. 192 °C. Found (%): C, 77.12; H, 8.75.
C H N NaO . Calculated (%): C, 78.53; H, 9.14. Reliable
4
4
61
2
2
N,N´ꢀBisꢀ(2,6ꢀdiisopropylphenyl)acenaphthyleneꢀ1,2ꢀdiꢀ
amine (4). Water vapor was slowly supplied to a solution
of complex 1, which was prepared from dppꢀBIAN (0.5 g,
elemental analysis data were not obtained because of high sensiꢀ
tivity of compound 7 to atmospheric oxygen and moisture. IR,
–
1
ν/cm : 1665 w, 1625 w, 1580 s, 1500 v.s, 1400 s, 1370 v.s,
1
.0 mmol) in THF, with cooling (10—0 °C) until the solution
1315 s, 1245 m, 1170 s, 1105 s, 1095 s, 1065 s, 905 m, 805 m,

2750
Russ.Chem.Bull., Int.Ed., Vol. 53, No. 12, December, 2004
Fedushkin et al.
8
2
3
80 s, 855 v.s, 845 v.s, 690 m. 1H NMR (200 MHz, C D ,
4. I. L. Fedushkin, V. A. Chudakova, A. A. Skatova, N. M.
Khvoinova, Yu. A. Kurskii, T. A. Glukhova, G. K. Fukin,
S. Dechert, M. Hummert, and H. Schumann, Z. Аnorg. Allg.
Chem., 2004, 630, 501.
6
6
0 °C), δ: 7.35, 7.15, 6.95, 6.55, 6.18, 4.98, 3.85, 3.45 (CHCH );
3
.18 (Et O); 1.20 (CHCH ); 0.92 (Et O).
2
3
2
Xꢀray diffraction study of compounds 5, 7, and dppꢀBIAN.
Xꢀray diffraction data for diamine 5 and dppꢀBIAN were meaꢀ
sured on a Siemens SMART CCD diffractometer (ω—ϕ scanꢀ
ning technique, MoꢀKα radiation, λ = 0.71073 Å, graphite
monochromator) at 173 K. Xꢀray diffraction data for compound
5. I. L. Fedushkin, A. A. Skatova, V. K. Cherkasov, V. A.
Chudakova, S. Dechert, M. Hummert, and H. Schumann,
Chem. — A Eur. J., 2003, 9, 5778.
6. I. L. Fedushkin, A. A. Skatova, A. N. Lukoyanov, V. A.
Chudakova, S. Dechert, M. Hummert, and H. Schumann,
Izv. Akad. Nauk, Ser. Khim., 2004, No. 12 [Russ. Chem.
Bull., Int. Ed., 2004, No. 12].
7. I. L. Fedushkin, N. M. Khvoinova, A. A. Skatova, and G. K.
Fukin, Angew. Chem., Int. Ed., 2003, 42, 5223.
8. M. W. van Laren and C. J. Elsevier, Angew. Chem., Int. Ed.,
1999, 38, 3715.
9. R. van Belzen, H. Hoffmann, and C. J. Elsevier, Angew.
Chem., Int. Ed., 1997, 36, 1743.
7
were collected on a Bruker AXS SMART APEX diffractometer
(
ω—ϕ scanning technique, MoꢀKα radiation, λ = 0.71073 Å,
graphite monochromator) at 100 K. The absorption corrections
were applied using the SADABS program.1 The structures were
solved by direct methods using the SHELXS97 program packꢀ
5
1
6
age and refined by the fullꢀmatrix leastꢀsquares method
against F 2 using the SHELXL97 program package. All nonꢀ
hydrogen atoms were refined anisotropically. The H atoms bound
to the N atoms were revealed from difference Fourier syntheses,
17
and the other hydrogen atoms were placed in idealized positions
10. G. A. Grasa, R. Singh, E. D. Stevens, and S. P. Nolan,
J. Organomet. Chem., 2003, 687, 269.
2
(
Uiso = 0.08 Å ). The atomic coordinates were deposited with
the Cambridge Structural Database.
11. A. E. Cherian, E. B. Lobkovsky, and G. W. Coates, Chem.
Commun., 2003, 20, 2566.
We thank Yu. A. Kurskii for recording NMR spectra
and T. I. Lopatina for measuring UV—Vis spectra.
This study was financially supported by the Russian
Foundation for Basic Research (Project No. 03ꢀ03ꢀ
12. M. D. Leatherman, S. A. Svejda, L. K. Johnson, and
M. Brookhart, J. Am. Chem. Soc., 2003, 125, 3068.
13. I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, N. M.
Khvoinova, A. Yu. Baurin, S. Dechert, M. Hummert, and
H. Schumann, Organometallics, 2004, 23, 3714.
3
2246), the State Program for the Support of Leading
1
4. A. A. Paulovicova, U. ElꢀAyaan, K. Shibayama, T. Morita,
and Y. Fukuda, Eur. J. Inorg. Chem., 2001, 2641.
Scientific Schools (Grant NShꢀ1652.2003.3), and the
Foundation for Support of National Science.
1
5. G. M. Sheldrick, Empirical Absorption Correction Program,
Universität Göttingen, Göttingen (Germany), 1996.
References
16. G. M. Sheldrick, Program for Crystal Structure Solution,
Universität Göttingen, Göttingen (Germany), 1990.
1
7. G. M. Sheldrick, Program for Crystal Structure Refinement,
Universität Göttingen, Göttingen (Germany), 1997.
1
2
. I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, and G. K.
Fukin, Angew. Chem., Int. Ed., 2003, 42, 3294.
. I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, V. K.
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. I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, G. K.
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Received May 19, 2004;
2
003, 18, 3336.
in revised form September 6, 2004