Synthesis and structures of new conformationally rigid 1-aza-1,3-dienes of the acenaphthene series

Article abstract of DOI:10.1007/s11172-007-0360-1

The Wittig reaction of 1-tert-butyliminoacenaphthen-2-one with benzylidenetriphenylphosphoranes produces new 1-aza-1,3-dienes of the acenaphthene series, which can bind butyllithium to the C=C bond of the enimine fragment C=C-C=N.

Full text of DOI:10.1007/s11172-007-0360-1

Russian Chemical Bulletin, International Edition, Vol. 56, No. 11, pp. 2284—2289, November, 2007
2284
Synthesis and structures of new conformationally rigid
1ꢀazaꢀ1,3ꢀdienes of the acenaphthene series
a
b
b
A. A. Skatova,a I. L. Fedushkin,a O. V. Maslova, M. Hummert, and H. Schumann
ꢀ
aG. A. Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences,
49 ul. Tropinina, 603950 Nizhnii Novgorod, Russian Federation.
Fax: +7 (831 2) 62 7497. Eꢀmail: igorfed@iomc.ras.ru
bInstitute of Chemistry, Technical University of Berlin,
Strasse des 17 Juni 135 , Dꢀ10623 Berlin, Germany.*
Fax: +49 (30) 3142 2168
The Wittig reaction of 1ꢀtertꢀbutyliminoacenaphthenꢀ2ꢀone with benzylidenetriphenylꢀ
phosphoranes produces new 1ꢀazaꢀ1,3ꢀdienes of the acenaphthene series, which can bind
butyllithium to the C=C bond of the enimine fragment C=C—C=N.
Key words: ketimines, imino ketones, enimines, phosphorus ylides, Wittig reaction, Xꢀray
diffraction study, acenaphthenes.
Among a great variety of metal complexes, derivatives
and studies of metal complexes bases on 1,3ꢀdienes and
ArꢀBIAN are promising lines of investigation in coordiꢀ
nation chemistry.
1ꢀAzaꢀ1,3ꢀdienes (enimines) occupy an intermediate
position between 1,3ꢀdienes and diimines. However, these
compounds have received much less attention compared
to dienes and diimines because their synthesis is more
difficult.10 Only a few such compounds are known. For
example, the synthesis of enimines A and B was docuꢀ
mented.11
of arylꢀsubstituted 1,3ꢀdienes and 1,4ꢀdiazaꢀ1,3ꢀdienes
(α,αꢀdiimines) have attracted particular attention in the
last few years. Transition metal complexes based on
1,3ꢀdienes are widely used in organic synthesis and serve
as polymerization catalysts.1,2 In addition, these comꢀ
plexes can be involved in various highly selective carboꢀ
metallation reactions, for example, with unsaturated
hydrocarbons and reagents containing carbon—oxygen or
carbon—nitrogen double bonds.3
Transition metal diimine complexes, in particular,
complexes with acenaphtheneꢀ1,2ꢀdiimine (BIAN) deꢀ
rivatives, have attracted great interest in recent years.
These complexes exhibit catalytic activity in the hydrogeꢀ
nation of alkynes,4 the C—C bond formation,5 the
cycloisomerization,6 and, particularly, the polymerizaꢀ
tion of various olefins7 and acrylic monomers.8
In recent years, we have synthesized Group I, II, XIII,
XIV, and XV metal complexes with the ArꢀBIAN ligands
(Ar is 2,6ꢀdiisopropylphenyl, 2,5ꢀdiꢀ
A: R1 = Me, R2 = 4ꢀMe, 4ꢀOMe, 4ꢀNMe2
B: R1 = OMe, R2 = H, 4ꢀMe, 3ꢀMe
Data on complexes with 1ꢀazaꢀ1,3ꢀdienes are
scarce. Most of these complexes were synthesized
by the exchange reactions of transition metal haꢀ
lides with magnesium or lithium salts of the corꢀ
responding enimines.10,12 For example, the first
homoleptic dinuclear titanium enimine complexes
[{(2,6ꢀPri2C6H3)N=CHCR=CHPh}2Ti]2 were syntheꢀ
sized by the reduction of two equivalents of 1ꢀazaꢀ1,3ꢀ
diene (2,6ꢀPri2C6H3)N=CHCR=CHPh (R = H or Me)
with two equivalents of magnesium in the presence of
TiCl4(THF)2.10
tertꢀbutylphenyl, or 2ꢀbiphenyl).
Magnesium and aluminum comꢀ
plexes with 1,2ꢀbis[(2,6ꢀdiisopropylꢀ
phenyl)imino]acenaphthene show
high reactivity with respect to variꢀ
ous classes of organic compounds
(ketones, nitriles, and halogen deꢀ
rivatives)9 and exhibit catalytic activity in the ringꢀopening
polymerization of lactides. Due to these facts, the synthesis
It is interesting that the deprotonation of enimine
ligands with bases can give Schrockꢀtype carbene comꢀ
* Institut für Chemie der Technischen Universität Berlin, Straße
des 17 Juni 135, Dꢀ10623 Berlin, Germany.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2206—2211, November, 2007.
1066ꢀ5285/07/5611ꢀ2284 © 2007 Springer Science+Business Media, Inc.

Acenaphthene 1ꢀazaꢀ1,3ꢀdienes
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 11, November, 2007 2285
Scheme 2
plexes. This characteristic feature distinguishes enimine
ligands from BIAN ligands. For example, the deprotoꢀ
nation of titanium enimine complexes with methyllithium
affords alkylidene complexes.10 It should be noted that
alkylidene complexes are often formed as intermediates
that activate C—H and C—C bonds and play the key role
in the olefin polymerization and metathesis.
Therefore, the chemistry of metal complexes with
enimine ligands is poorly known and, consequently, is a
promising field of investigation. In the present study, we
synthesized two new enimines based on acenaphthene
and investigated their structures and reactivity with reꢀ
spect to bases.
Results and Discussion
Synthesis and characterization of compounds 1—5.
Imino ketone 1 was synthesized by the condensation of
acenaphthenequinone with excess tertꢀbutylamine in boilꢀ
ing toluene in the presence of concentrated formic acid
for 24 h (Scheme 1).
R = H (a), Me (b)
ciated with their synthesis and isolation were carried out
in vacuo. In the present study, ylide 3b was synthesized for
the first time. This compound was characterized by
elemental analysis, NMR spectroscopy, and IR spectroꢀ
scopy. The crystal structure of compound 3b was estabꢀ
lished by Xꢀray diffraction (Fig. 1, Tables 1 and 2). The
IR spectra of ylides 3a,b show stretching bands of the
Scheme 1
P=C bond at 973 (3a) and 978 cm–1 (3b). The H NMR
1
spectrum of compound 3b in benzene has two singlets
for the protons of the methyl groups in the ortho and
para positions of the benzene ring. Due to the splitting
from the phosphorus atom, the proton at the P=C double
bond gives a doublet at δ 2.47.
Desired enimines 4a,b were synthesized in 87 and
54% yields, respectively, by refluxing equimolar amounts
of imino ketone 1 and phosphorus ylides 3a,b in toluene
for 3 h (Scheme 3). The IR spectra of compounds 4a,b
Reagents and conditions: toluene, HCOOH, ∆, 24 h.
To shift the equilibrium of the reaction toward the
formation of product 1, we used molecular sieves as water
scavengers. It should be noted that, unlike the reactions
with anilines, the reaction with excess tertꢀbutylamine
does not produce the corresponding diimine. Compound 1
was prepared in 43% yield and was identified by elemental
analysis, IR spectroscopy, and 1H NMR spectroscopy.
Scheme 3
1
The H NMR spectrum of compound 1 in benzene
shows a singlet for nine methyl protons of the tertꢀbutyl
group (δ 1.75) and signals for six nonequivalent aromatic
protons of the naphthalene moiety of molecule 1. The
IR spectrum shows the presence of C=O (1718 cm–1) and
C=N (1626 cm–1) groups in molecule 1.
Phosphonium salts 2a and 2b were prepared by refluxꢀ
ing triphenylphosphine with benzyl chloride and 2,4,6ꢀtriꢀ
methylbenzyl chloride, respectively, in toluene for 24 h.
Phosphorus ylides 3a and 3b were synthesized by the
deprotonation of salts 2a and 2b with butyllithium in
hexane (Scheme 2).
Ylides 3a,b were isolated from hexane in yields higher
than 90% as bright orange (3a) or red (3b) powders. Since
these compounds are unstable in air, all operations assoꢀ
R = H (a), Me (b)

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Skatova et al.
show an absorption band characteristic of the C=N double
bond at 1608 (4a) or 1612 cm–1 (4b). The 1H NMR
spectra in benzene (for 4a) and chloroform (for 4b) unꢀ
ambiguously confirm the structures of enimines 4a,b. The
corresponding detailed assignments are given in the Exꢀ
perimental section. The structure of compound 4b was
confirmed by Xꢀray diffraction (Fig. 2, see Tables 1 and 2).
Since enimines can eliminate the hydrogen atom from
the C=C double bond to form the carbon—metal bond,
we examined the possibility of the deprotonation of comꢀ
pound 4b with nꢀbutyllithium. The reaction mixture turned
blueꢀgreen, and a green finely crystalline precipitate along
with red rhombic crystals were obtained immediately afꢀ
ter mixing hexane solutions of BunLi and 4b. Both prodꢀ
ucts have similar solubilities, due to which their quantiꢀ
tative separation was impossible. Several large red crysꢀ
tals were separated mechanically and studied by Xꢀray
diffraction. This product was demonstrated to be diꢀ
meric lithium amide 5 that is formed as a result of the
1,4ꢀaddition of the organolithium compound to the conꢀ
jugated enimine fragment C=C—C=N (Scheme 4).
H(1)
C(1)
C(2)
C(23)
P
C(11)
C(17)
Fig. 1. Molecular structure of phosphorus ylide 3b. The hydroꢀ
gen atoms, except for the H(1) atom, are omitted.
Scheme 4
C(1)
C(2)
C(13)
N(1)
H(13)
Fig. 2. Molecular structure of enimine 4b. The hydrogen atoms,
except for the H(13) atom, are omitted.
C(2)
C(1)
Interestingly, the dissolution of several individual red
crystals in tetrahydrofuran gave rise to a blue solution.
The reactions with the use of other bases, such as
potassium tertꢀbutoxide and lithium diisopropylamide, did
not give the desired deprotonation products of enimine 4b
as well. The reactions of these bases with compound 4b
afforded blue solutions. Unfortunately, we failed to isoꢀ
late individual components from these solutions.
N(1)
H(13)
C(13)
Li(1)
Molecular structures of compounds 3b, 4b, and 5. The
structures of compounds 3b, 4b, and 5 were established by
Xꢀray diffraction (Figs 1—3). Crystals of compounds 3b
and 4b suitable for Xꢀray diffraction were grown from
benzene and hexane, respectively. Selected bond lengths
and bond angles in compounds 3b, 4b, and 5 are listed in
Table 1. The crystallographic data and the Xꢀray data
collection and refinement statistics are given in Table 2.
The phosphorus atom in ylide 3b has a distorted tetraꢀ
hedral coordination (see Fig. 1), as evidenced by the bond
Fig. 3. Molecular structure of complex 5. The hydrogen atoms,
except for the H(13) atom, are omitted.
angles at the phosphorus atom (approximately equal
to 109°; see Table 1). The C(1)—P distance (1.688(2) Å)
is noticeably shorter than the other P—C bonds (P—C(23),
1.816(2) Å; P—C(11), 1.816(2) Å; P—C(17), 1.834(2) Å),

Acenaphthene 1ꢀazaꢀ1,3ꢀdienes
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 11, November, 2007 2287
Table 1. Selected bond lengths (d) and bond angles (ω) in molꢀ
ecules 3b, 4b, and 5
charge on the phosphorus atom and the negative charge
on the carbon atom.
In 1ꢀazaꢀ1,3ꢀdiene 4b (see Fig. 2), the bond
lengths in the conjugated enimine fragment
C(13)=C(2)—C(1)=N(1) (C(13)—C(2), 1.330(3) Å;
C(2)—C(1), 1.518(3) Å; C(1)—N(1), 1.274(3) Å) conꢀ
firm the presence of the central C(2)—C(1) single bond
and two C(13)=C(2) and C(1)=N(1) double bonds, which
are similar in length to the corresponding bonds in the
molecule of enimine PhCH=CH—CH=N(2,6ꢀPri2C6H3)
(1.351(5), 1.438(6), and 1.278(5) Å).10a
The conformational rigidity of the enimine is associꢀ
ated with the fact that the carbon atoms of the enimine
system are involved in the fused hydrocarbon fragment
(the acenaphthylene moiety). The C(13)—H(13) distance
is 0.929(5) Å. However, due to the absence of steric crowdꢀ
ing at the nitrogen atom, its lone electron pair is accesꢀ
sible to the complexation with metal cations, resulting in
the formation of the dimeric structure of compound 5.
The molecular structure of the complex, which was
prepared by the addition of the butyllithium molecule to
enimine 4b, is shown in Fig. 3. According to the Xꢀray
diffraction data, molecule 5 exists as a centrosymmetric
dimer with two bridging lithium atoms bound to the
Bond
d/Å
Angle
ω/deg
3b
P—C(1)
1.688(2)
1.834(2)
1.816(2)
1.816(2)
1.457(3)
C(1)—P—C(17)
C(1)—P—C(11)
C(1)—P—C(23)
C(17)—P—C(11)
C(11)—P—C(23)
C(23)—P—C(17)
117.5(1)
115.5(1)
106.9(1)
106.1(1)
103.9(1)
105.7(1)
P—C(17)
P—C(11)
P—C(23)
C(1)—C(2)
4b
5
N(1)—C(1)
C(2)—C(13) 1.330(3)
H(13)—C(13) 0.929(5)
1.274(3)
N(1)—C(1)—C(2)
C(13)—C(2)—C(1)
H(13)—C(13)—C(2) 116.7(3)
118.2(2)
123.5(2)
C(1)—C(2)
1.518(3)
C(2)—C(13) 1.527(6)
C(1)—C(2)—C(13)
C(1)—N(1)—Li(1)
C(2)—C(1)—N(1)
121.8(4)
110.9(3)
126.6(4)
C(1)—C(2)
C(1)—N(1)
Li(1)—N(1)
1.389(6)
1.402(5)
2.024(9)
H(13)—C(13)—C(2) 104.0(3)
H(13)—C(13) 1.00(1)
which is indicative of the contribution of the ionic comꢀ
ponent to the binding and the presence of the positive
Table 2. Crystallographic parameters and the Xꢀray diffraction data collection and refinement statistics for compounds 3b,
4b, and 5
Parameter
3b•1/2C6H6
31H30
4b
5
Molecular formula
Molecular weight
T/К
C
P
C26H27
353.49
173(2)
N
C60H72Li2N2
835.08
433.52
173(2)
173(2)
Crystal system
Space group
Monoclinic
P2(1)/n
Monoclinic
P2(1)/n
Monoclinic
C2/c
a/Å
b/Å
c/Å
α/deg
12.156(5)
16.028(5)
12.673(5)
90.000(5)
91.939(5)
90.000(5)
2467.7(16)
4
10.2075(4)
9.0550(4)
22.7332(10)
90.00
90.897(2)
90.00
27.004(2)
8.6094(6)
24.225(2)
90.00
119.098(5)
90.00
4921.3(7)
4
1.127
β/deg
γ/deg
V/Å3
2100.95(15)
4
Z
d/g cm–3
1.167
0.127
1.118
0.064
µ/mm–1
0.063
F(000)
924
760
1808
Crystal dimensions/mm
Scan range, θ/deg
Indices h, k, l of measured reflections
0.60×0.42×0.35
2.05—25.00
–14 ≤ h ≤ 9
–19 ≤ k ≤ 18
–15 ≤ l ≤ 15
15204
0.26×0.36×0.48
1.79—30.56
–12 ≤ h ≤ 10
–11 ≤ k ≤ 9
–26 ≤ l ≤ 28
14035
0.28×0.36×0.48
1.73—30.63
–30 ≤ h ≤ 30
–8 ≤ k ≤ 9
–27 ≤ l ≤ 27
13561
Number of observed reflections
Number of independent reflections (Rint
Goodnessꢀofꢀfit on F 2
)
4336 (0.1247)
1.012
4134 (0.0884)
0.975
3859 (0.1270)
1.074
R1/wR2 (I > 2σ(I ))
R1/wR2 (based on all reflections)
Residual electron density/e Å3,
0.0510/0.1172
0.0845/0.1331
0.0620/0.1362
0.1419/0.1719
0.0825/0.2009
0.1220/0.2205
ρ
max/ρ
0.338/–0.414
0.159/–0.227
0.322/–0.302
min

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Skatova et al.
Benzylidenetriphenylphosphorane (3a). A hexane solution of
nꢀbutyllithium (4 mL of a 1.25 M solution, 5 mmol) was added
to a suspension of phosphonium salt 2a (1.73 g, 4 mmol) in
hexane. The solution turned bright orange. Hexane was removed
from the reaction mixture, and diethyl ether was added. This led
to the formation of an orange precipitate of phosphorus ylide
and colorless lithium chloride. Diethyl ether was removed, toluꢀ
ene (50 mL) was added by condensation, a colorless precipitate
of lithium chloride was removed by filtration, and a solution of
3a in toluene was obtained. The latter can be used for the in situ
synthesis of 4a. After the complete removal of the solvent, ylide
3a was obtained as an orange powder. The yield was 1.52 g
(97%). The 1H NMR spectrum and m.p. 175—178 °C are comꢀ
pletely identical to those published in the literature.15
(2,4,6ꢀTrimethylbenzylidene)triphenylphosphorane (3b). The
procedure for the synthesis and isolation is analogous to that
used for 3a. Phosphorus ylide 3b was obtained as a red powder.
The yield was 98%, m.p. 58—61 °C. Found (%): C, 85.30;
H, 6.79. C28H27P (394.49 g mmol–1). Calculated (%): C, 85.27;
H, 6.88. IR (Nujol mulls), ν/cm–1: 978 (P=C). 1H NMR
(200 MHz, C6D6, 20 °C), δ: 7.82—7.68 and 7.08—6.88 (both m,
17 H, Ar); 2.47 (d, 1 H, =C—H, J = 7.7 Hz); 2.35 (s, 6 H,
oꢀMe); 2.30 (s, 3 H, pꢀMe). The crystallization from benzene
gave red rhombic crystals containing one benzene molecule per
two molecules 3b in the unit cell.
1ꢀ(tertꢀButylimino)ꢀ2ꢀ(phenylmethylidene)acenaphthene (4a).
A solution of imino ketone 1 (1.02 g, 4 mmol) in toluene (10 mL)
was added to a solution of phosphorus ylide 3a (1.52 g, 4 mmol)
in toluene (15 mL) in vacuo. The reaction mixture was refluxed
for 3 h. Then toluene was removed, and hexane was condensed
into the mixture, which was accompanied by the formation of a
colorless precipitate of triphenylphosphine oxide. The precipiꢀ
tate was separated by filtration. Hexane was removed from the
filtrate, and isopropyl alcohol was added. The paleꢀyellow preꢀ
cipitate of enimine 4a that formed was separated by filtration,
twice washed on a filter with isopropyl alcohol, and dried. The
yield was 1.17 g (87%), m.p. 108—110 °C, paleꢀyellow powder.
Found (%): C, 88.52; H, 6.69. C23H21N (311.42 g mol–1). Calꢀ
culated (%): C, 88.70; H, 6.80. IR (Nujol mulls), ν/cm–1: 1608
(C=N). 1H NMR (200 MHz, C6D6, 20 °C), δ: 8.45 (s, 1 H,
=CH); 8.03 and 7.84 (both d, 1 H each, Ar of the naphthalene
moiety, J = 7.3 Hz); 7.65—7.46 (m, 4 H, Ar of the naphthalene
moiety); 7.44—7.10 (m, 5 H, C6H5—CH=); 1.75 (s, 9 H, But).
1ꢀ(tertꢀButylimino)ꢀ2ꢀ[(2,4,6ꢀtrimethylphenyl)methylꢀ
idene]acenaphthene (4b). The procedure for the synthesis and
isolation is analogous to that used for 4a. Enimine 4b was crysꢀ
tallized from hexane as paleꢀyellow rhombic crystals. The yield
was 54%, m.p. 167—169 °C. Found (%): C, 87.99; H, 7.71.
C26H27N (353.49 g mol–1). Calculated (%): C, 88.34; H, 7.70,
N, 3.96. IR (Nujol mulls), ν/cm–1: 1612 (C=N). 1H NMR
(200 MHz, CDCl3, 20 °C), δ: 8.12 and 7.88 (both d, 1 H each,
Ar of the naphthalene moiety, J = 7.3 Hz, J = 8.2 Hz); 7.80 (s,
1 H, =CH); 7.68—7.62 (m, 2 H, Ar of the naphthalene moiety);
7.40—7.30 (m, 1 H, Ar of the naphthalene moiety); 7.02 (s, 2 H,
=CH—C6H2Me3); 6.82 (d, 1 H, Ar of the naphthalene moiety,
J = 6.9 Hz); 2.42 (s, 3 H, pꢀMeC6H2); 2.27 (s, 6 H, oꢀMeC6H2);
1.73 (s, 9 H, But).
nitrogen atoms of the enimine fragment. The aceꢀ
naphthylene planes are parallel to each other and are
almost orthogonal to the planes of the phenyl substituꢀ
ents. The addition of the BunLi molecule at 1,4 posiꢀ
tions of the enimine fragment C(13)—C(2)—C(1)—N(1)
leads to a change in the character of bonds in this
fragment. Thus, the C(13)—C(2) and C(1)—N(1) disꢀ
tances (1.527(6) and 1.402(5) Å, respectively) are longer
than the corresponding distances in the starting 1ꢀazaꢀ
1,3ꢀdiene 4b (1.3330(3) and 1.274(3) Å). On the conꢀ
trary, the C(2)—C(1) bond in complex 5 (1.389(6) Å)
is shorter than that in complex 4b (1.518(3) Å). This
confirms the electron density redistribution in the
C(13)—C(2)—C(1)—N(1) fragment, resulting in the fact
that the C(13)—C(2) and C(1)—N(1) bonds are single,
whereas the C(2)—C(1) bond is double.
Experimental
Phosphorus ylides 3a,b are sensitive to atmospheric moisꢀ
ture and oxygen. Hence, all operations associated with the synꢀ
thesis, isolation, and identification of these compounds were
carried out in evacuated Schlenkꢀtype apparatus. Toluene,
hexane, diethyl ether, and benzene were dried and stored over
sodium benzophenone ketyl and condensed into a reaction vesꢀ
sel immediately before use. The IR spectra were recorded on a
SpecordꢀM80 spectrometer in Nujol mulls. The 1H NMR specꢀ
tra were measured on a Bruker DPX 200 spectrometer.
1ꢀ(tertꢀButylimino)acenaphthenꢀ2ꢀone (1). tertꢀButylamine
(5.5 mL, 52 mmol) and 98% formic acid (1 mL) were added to a
suspension of acenaphthenequinone (4.55 g, 25 mmol) in toluꢀ
ene (100 mL). The reaction mixture was refluxed for 24 h with
continuous stirring with the use of a Soxhlet apparatus containꢀ
ing molecular sieves for absorption of water that was eliminated
during the reaction. Then toluene was completely removed from
the reaction mixture. The solid residue consisting of the product
and unconsumed acenaphthenequinone was repeatedly extracted
with hexane on a backꢀup filter. Compound 1 was isolated by
crystallization from hexane as paleꢀyellow needleꢀlike crystals
(2.55 g, 43%), m.p. 136—138 °C (from hexane). Found (%):
C, 81.01; H, 6.33. C16H15NO (237.30 g mmol–1). Calcuꢀ
lated (%): C, 80.98; H, 6.37. IR (Nujol mulls), ν/cm–1: 1718
(C=O); 1626 (C=N). 1H NMR (200 MHz, C6D6, 20 °C), δ:
7.92 and 7.62 (both d, 1 H each, Ar, J = 7.3 Hz); 7.49 and 7.43
(both d, 1 H each, Ar, J = 8.1 Hz); 7.22 and 7.07 (both dd,
1 H each, Ar, J = 7.3 Hz, J = 8.1 Hz); 1.75 (s, 9 H, But).
Benzyltriphenylphosphonium chloride (2a). Benzyl chloride
(10 mL, 90 mmol) was added to a solution of triphenylphosphine
(10.52 g, 40 mmol) in toluene (125 mL). The reaction mixture
was refluxed for 12 h with continuous stirring. The colorless
precipitate that formed was separated, twice washed on a filter
with toluene, and dried. The yield was 14.90 g (96%), m.p.
272—274 °C is consistent with the data published in the litꢀ
erature.13
(2,4,6ꢀTrimethylbenzyl)triphenylphosphonium chloride (2b).
The procedure for the synthesis and isolation is analogous to
that used for 2a. The yield was 95%, m.p. 228—230 °C is consisꢀ
tent with the data published in the literature.14
Dimer of lithium NꢀtertꢀbutylꢀNꢀ{2ꢀ[1ꢀ(2,4,6ꢀtrimethylꢀ
phenyl)pentꢀ1ꢀyl]acenaphthenꢀ1ꢀyl}amide (5). A solution of
nꢀbutyllithium in hexane (0.8 mL of a 1.25 M solution, 1 mmol)
was added to a solution of compound 4b (0.36 g, 1 mmol) in

Acenaphthene 1ꢀazaꢀ1,3ꢀdienes
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 11, November, 2007 2289
hexane (15 mL) in vacuo. The color of the solution changed
from paleꢀyellow to blueꢀgreen, and a green finely crystalline
precipitate containing inclusions of red rhombic crystals was
obtained. Both products are similar in solubility, due to which
their quantitative separation was impossible. Several large red
crystals were separated mechanically and studied by Xꢀray difꢀ
fraction.
Xꢀray diffraction study of compounds 3b, 4b, and 5. Xꢀray
diffraction data sets were collected on a Siemens SMART CCD
diffractometer (ωꢀϕꢀscanning technique, MoꢀKα radiation, λ =
0.71073 Å, graphite monochromator) at 173 K. Absorption
corrections were applied using the SADABS program.16 The
structures were solved by direct methods with the use of the
SHELXS97 program package17 and refined by the fullꢀmatrix
leastꢀsquares method on F2 using the SHELXL97 program
package.18 All nonhydrogen atoms were refined anisotropiꢀ
cally. The hydrogen atoms were placed in idealized positions
(Uiso = 0.08 Å3).
N. I. Ivancheva, I. I. Oleinik, S. Ya. Khaikin, and I. V.
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8. I. Kim, J. M. Hwang, J. K. Lee, C. S. Ha, and S. I. Woo,
Macromol. Rapid Commun., 2003, 24, 508.
9. (a) I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, G. K.
Fukin, S. Dechert, and H. Schumann, Eur. J. Inorg. Chem.,
2003, 3336; (b) I. L. Fedushkin, A. A. Skatova, V. K.
Cherkasov, V. A. Chudakova, S. Dechert, M. Hummert,
and H. Schumann, Chem. — Eur. J., 2003, 9(23), 5778;
(c) I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, and
G. K. Fukin, Angew. Chem., 2003, 115, 3416; Angew. Chem.,
Int. Ed., 2003, 42, 3294; (d) I. L. Fedushkin, N. M.
Khvoinova, A. A. Skatova, and G. K. Fukin, Angew. Chem.,
Int. Ed., 2003, 42(42), 5223; (e) I. L. Fedushkin, V. A.
Chudakova, G. K. Fukin, S. Dechert, M. Hummert, and
H. Schumann, Izv. Akad. Nauk, Ser. Khim., 2004, 2634 [Russ.
Chem. Bull., Int. Ed., 2004, 2744]; (f) I. L. Fedushkin, A. A.
Skatova, G. K. Fukin, M. Hummert, and H. Schumann,
Eur. J. Inorg. Chem., 2005, 2332; (g) 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, 2641 [Russ. Chem. Bull., Int. Ed., 2004, 2751];
(h) I. L. Fedushkin, A. A. Skatova, V. A. Chudakova, V. K.
Cherkasov, G. K. Fukin, and M. A. Lopatin, Eur. J. Inorg.
Chem., 2004, 388; (i) 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. Anorg. Allg. Chem., 2004, 630, 501; (j) I. L.
Fedushkin, A. A. Skatova, V. A. Chudakova, V. K.
Cherkasov, S. Dechert, and H. Schumann, Izv. Akad. Nauk,
Ser. Khim., 2004, 2051 [Russ. Chem. Bull., Int. Ed., 2004,
2142]; (k) H. Schumann, M. Hummert, A. N. Lukoyanov,
and I. L. Fedushkin, Organometallics, 2005, 24, 3891; (l) I. L.
Fedushkin, A. A. Skatova, M. Hummert, and H. Schumann,
Eur. J. Inorg. Chem., 2005, 1601; (m) I. L. Fedushkin, V. A.
Chudakova, A. A. Skatova, and G. K. Fukin, Heteroatom
Chem., 2005, 16, 663.
This study was financially supported by the Russian
Foundation for Basic Research (Project No. 05ꢀ03ꢀ
32643).
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Received July 9, 2007;
in revised form October 2, 2007