1,2-Bis(imino)acenaphthene complexes of molybdenum and nickel

Article abstract of DOI:10.1039/b902709b

Molybdenum hexacarbonyl reacts with 1,2-bis[(2,6-diisopropylphenyl)imino] acenaphthene (1, dpp-BIAN) and 1,2-bis[(trimethylsilyl)imino]acenaphthene (2, tms-BIAN) in toluene to produce (dpp-BIAN)Mo(CO)₄ (3) and (tms-BIAN)Mo(CO)₄ (4),

Full text of DOI:10.1039/b902709b

View Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/dalton | Dalton Transactions
1,2-Bis(imino)acenaphthene complexes of molybdenum and nickel†
Igor L. Fedushkin,*a Alexandra A. Skatova,a Anton N. Lukoyanov,a Nalalie M. Khvoinova,a
Alexander V. Piskunov,a Alexander S. Nikipelov,a Georgy K. Fukin,a Konstantin A. Lysenko,b
Elisabeth Irranc and Herbert Schumannc
Received 10th February 2009, Accepted 27th March 2009
First published as an Advance Article on the web 27th April 2009
DOI: 10.1039/b902709b
Molybdenum hexacarbonyl reacts with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (1,
dpp-BIAN) and 1,2-bis[(trimethylsilyl)imino]acenaphthene (2, tms-BIAN) in toluene to produce
(dpp-BIAN)Mo(CO)4 (3) and (tms-BIAN)Mo(CO)4 (4), respectively. The reaction of [CpNi(CO)]2 with
1 yields (dpp-BIAN)NiCp (5). Metathesis between Li2(tms-BIAN) and NiCl2(dppe) affords the Ni(0)
complex (tms-BIAN)Ni(dppe) (6). The diamagnetic compounds 3, 4 and 6 have been characterized by
1H, 29Si and 31P NMR spectroscopy, IR spectroscopy and elemental analysis. The ESR spectrum of the
paramagnetic compound 5 indicates the presence of Ni(I) coordinated by Cp and a neutral dpp-BIAN
ligand. The molecular structures of 3–6 have been determined by single-crystal X-ray analysis.
Zn–Zn14 and Ga–Ga15 bonds and of the germylenes (dpp-
Introduction
BIAN)Ge16 and (dpp-BIAN)GeCl.17 Very recently, the previous
development in the field of the coordination chemistry of BIAN
ligands with s- and p-block elements has been reviewed.18
a-Diimine ligands proved to be useful tools for fine tun-
ing the reactions of metal complexes. In this context, 1,2-
bis(imino)acenaphthenes (BIANs) have attracted increasing atten-
tion during the last years. Although BIAN’s have been known since
1960,1–3 they were not used as ligands in transition metal chemistry
before 1990. The pioneers in this field have been the teams around
Elsevier, Brookhart and Coates. They could demonstrate that
transition metal complexes with neutral BIAN ligands catalyze
reactions like alkyne hydrogenation,4 C–C bond formation,5
cycloisomerisation,6 and polymerisation of olefins7 and acrylic
monomers.8 In 1995, Brookhart and co-workers reported9 on
BIAN supported nickel(II) complexes, which are extremely active
catalysts for the conversion of ethylene and a-olefins into high
molecular syndiotactic polymers.9 Furthermore, BIAN coordi-
To date, there are only two examples of transition metal
complexes with anionic BIAN ligands, e.g. (F-BIAN)2Ni
and (F-BIAN)3Co (F-BIAN = 1,2-bis[{3,5-bis(trifluoromethyl)-
phenyl}imino]acenaphthene).19 The Ni complex comprises the di-
valent metal ion with pairs of radical-anionic ligands, whereas the
Co complex is best described as a Co(I) complex with two neutral
and one radical-anionic F-BIAN ligands. In this study, we in-
tended the preparation of d-metal complexes with anionic BIANs
by the reactions of Mo and Ni carbonyl complexes with dpp-
BIAN and tms-BIAN. Here, we report on the synthesis and char-
acterisation of (dpp-BIAN)Mo(CO)4 (3), (tms-BIAN)Mo(CO)4
(4), (dpp-BIAN)NiCp (5) and (tms-BIAN)Ni(dppe) (6).
3
nated h -allyl dicarbonyl molybdenum(II) derivatives represent a
new class of catalysts for the epoxidation of cycloalkenes.10
In 2003, we started our investigations of BIAN complexes
of main group metals. In a series of papers we reported on
group I,11 II12 and XIII13 metal complexes coordinated by
1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN).
Over the course of these studies it turned out that dpp-BIAN
can act as an efficient “electron sponge” by accepting up to four
electrons.11 Furthermore, the unique stereoelectronic properties
of dpp-BIAN’s allowed the isolation of complexes with direct
Results and discussion
Synthesis and characterisation of compounds 3–6
Mo(CO)6 reacts with equimolar amounts of dpp-BIAN (1) and
tms-BIAN (2) (Scheme 1) in boiling toluene within 12 h to
give (dpp-BIAN)Mo(CO)4 (3) and (tms-BIAN)Mo(CO)4 (4),
respectively, in yields up to 80%. In the course of the reactions,
the colour of the solutions change from initially orange to bright
green (3) or deep blue (4) colours, which also show the isolated
crystalline compounds. The reaction of Mo(CO)6 with dpp-BIAN
runs much faster in THF and is completed after 6 h. Furthermore,
this reaction can be carried out in air, since the reactants as well
aG. A. Razuvaev Institute of organometallic chemistry, Russian academy of
sciences, Tropinina str. 49, 603950, Nizhny Novgorod, Russian Federation.
E-mail: igorfed@iomc.ras.ru; Fax: +7 831 4627495; Tel: +7 831 4629631
bA. N. Nesmeyanov Institute of organoelement compounds, Russian academy
of sciences, Vavilova str. 28, 119991, Moscow, Russian Federation. E-mail:
kostya@xray.ineos.ac.ru; Fax: +7 499 1355085; Tel: +7 499 1359214
cTechnische Universita¨t Berlin, Institut fu¨r Chemie, Strasse des 17. Juni 135,
D-10623 Berlin, Germany. E-mail: schumann@chem.tu-berlin.de; Fax: +49
30 31422168; Tel: +49 30 31423984
† Electronic supplementary information (ESI) available: References on
DAD-, bipy- and phen-Mo(CO)4 complexes. CCDC reference numbers
719953–719956. For ESI and crystallographic data in CIF or other
electronic format see DOI: 10.1039/b902709b
Scheme 1 Syntheses of compounds 3 and 4.
Dalton Trans., 2009, 4689–4694 | 4689
This journal is
The Royal Society of Chemistry 2009
©

View Online
as product 3 are air-stable compounds. In contrast, tms-BIAN (2)
is sensitive to moisture and therefore the synthesis of complex 4
has to be carried out under an inert atmosphere. Analytical grade
samples and crystals suitable for single-crystal X-ray analysis of
3 and 4 have been obtained by crystallisation from hexane and
toluene, respectively.
The IR spectra of 3 and 4 show the carbonyl stretching
modes in the expected range (3: 2007, 1898 and 1859 cm-1;
3
4: 2008, 1873 and 1838 cm-1). For comparison, in [Mo(h -
C3H5)X(CO)2(4-ClPh-BIAN)]10 (X = Cl, Br; 4-ClPh-BIAN = 1,2-
bis[(4-chlorophenyl)imino]acenaphthene) these modes appear at
1928, 1869 (X = Cl) and 1946, 1869 cm-1(X = Br). The 1H NMR
spectra of 3 and 4 show the expected signals for the protons of the
BIAN ligands, even though they are somewhat shifted compared
to the signals of free dpp-BIAN (1) and tms-BIAN (2). Thus, the
signals of the methine protons of the isopropyl groups in 3 are
centred at 3.50 ppm (cf. 1 3.36 ppm20) and the methyl protons of
those groups give rise to two doublet signals at 1.50 and 0.80 ppm
(cf. 1 1.41 and 1.17 ppm20).
Fig. 1 ESR signal of 5 (toluene, 120 K) (a) and its simulation (b).
The reaction of [CpNi(CO)]2 with the twofold molar amount
of dpp-BIAN (1) in boiling toluene is accompanied by a colour
change of the solution from red-brown to green and is completed
within 1 h. Work-up of the solution by evaporation of the solvent
and recrystallisation of the remaining solid from hexane affords
air stable, deep green crystals of (dpp-BIAN)NiCp (5) in almost
quantitative yield (Scheme 2). The IR spectrum of 5 shows
cyclopentadienyl ring absorptions at 1003 and 831 cm-1 and the
Scheme 3 Synthesis of compound 6.
The methylene multiplets are broadened and appear at 1.90 and
1.63 ppm. Also the two phosphorus atoms of the dppe ligand are
non-equivalent and give rise to two signals at 21.5 and 18.1 ppm
in the 31P NMR spectrum. On the other hand, in the H as well
nC= stretching mode of the dpp-BIAN ligand at 1650 cm-1.
N
1
as in the 29Si NMR spectrum of 6, the trimethylsilyl groups of
the tms-BIAN ligand give rise for a singlet signal at 0.39 ppm
and -5.3 ppm, respectively (cf. 222 0.51 ppm and -1.1 ppm), thus
suggesting a mirror plane dividing the tms-BIAN ligand in 6 into
two equal parts. The IR spectrum shows the nC=N stretching mode
of the tms-BIAN ligand at 1646 cm-1, thus indicating the neutral
form of the tms-BIAN ligand in 6.
Molecular structures of compounds 3–6
Scheme 2 Synthesis of compound 5.
The molecular structures of compounds 3, 4, 5 and 6, determined
by single-crystal X-ray diffraction, are depicted in Fig. 2, 3, 4, and
5, respectively. X-Ray quality crystals were obtained from hexane
(3, 5, 6) and toluene (4). The crystal data are presented in Table 1,
selected bond distances and bond angles are listed in Table 2.
Compounds 3 and 4 represent octahedral Mo(0) complexes. The
CCDC search reveals three diazadiene-, ten bipyridyl- and two
phenantrolinetetracarbonylmolybdenum analogues of complexes
3 and 4 (see ESI).† The unit cell of 3 consists of two crystallo-
graphically independent molecules those geometrical parameters
are very similar. The deviation of the Mo atoms from the N(1)–
Complex 5 is paramagnetic in the solid state as well as in
solution. The anisotropic ESR signal of 5 in toluene (120 K)
exhibits an orthorhombic symmetry of the g-tensor (Fig. 1).
The g2 and g3 tensor components reveal a hyperfine coupling
to two equivalent 14N nuclei (g1 = 2.183, g2 = 2.109, g3 = 1.993,
A2 = 0.98 mT, A3 = 1.30 mT). These signal parameters are similar
to those of (2,2¢-bipy)NiCp.21 Thus, compound 5 represents a 19-
electron nickel(I) complex.
The addition of (dppe)NiCl2 (dppe = 1,2-bis(diphenylpho-
sphino)ethane) to the deep blue solution of Li2(tms-BIAN),
prepared in situ from 2 and excess lithium metal in toluene,
causes a change in the colour of the reaction mixture to red
brown. Appropriate work-up of this mixture allows the isolation
of deep red crystals of (tms-BIAN)Ni(dppe) (6) in a yield of 58%
(Scheme 3).
˚
C(1)–C(2)–N(2) plane in 3 and 4 are 0.383/0.026 and 0.772 A,
respectively. For comparison, in the complex (Me2bipy)Mo(CO)4
(Me2bipy = 6,6¢-dimethyl-2,2¢-bipyridyl) this value is 0.477 A.23 In
˚
both 3 and 4 the sum of the angles formed by the bonds of the metal
to its equatorial ligand atoms is very close to the ideal value of
360◦ (3, 359.9◦; 4, 359.7◦). Due to the higher steric bulk of the two
2,6-i-Pr2C6H3 substituents of the dpp-BIAN ligand in 3 compared
to the two Me3Si groups of the tms-BIAN ligand in 4, the angle
The 1N NMR spectrum of 6 in benzene-d6 reveals non-
equivalence of the two methylene groups of the dppe ligand.
4690 | Dalton Trans., 2009, 4689–4694
This journal is
The Royal Society of Chemistry 2009
©

View Online
Fig. 2 Molecular structure of complex 3. Hydrogen atoms are omitted.
Thermal ellipsoids are drawn at 30% probability.
Fig. 5 Molecular structure of complex 6. Hydrogen atoms are omitted.
Thermal ellipsoids are drawn at 40% probability.
between the axially positioned carbonyl groups is smaller in 3
(C(39)–Mo–C(40), 163.2◦) than in 4 (C(19)–Mo–C(20), 172.1◦).
In 3 the phenyl ring planes are orthogonal to the diimine plane
as it is the case in free dpp-BIAN and in all its metal complexes.
The bonds C(1)–N(1), C(2)–N(2), and C(1)–C(2) of the diimine
moiety in 3 and 4 correspond quite well with those of the free
˚
BIAN ligands 1 and 2, e.g. 3, C(1)–N(1) (1.293(4) A), C(2)–N(2)
˚
˚
(1.300(4) A) and C(1)–C(2) (1.480(5) A); 1 (C(1)–N(1) and C(2)–
20
˚
˚
N(2) both 1.282(4) A, C(1)–C(2) 1.534(6) A) as well as with the
data obtained for the antimony complex (dpp-BIAN)SbCl3 (N(1)–
C(1) 1.288(2), N(2)–C(2) 1.277(3), C(1)–C(2) 1.524(3) A),24 which
˚
also contains the dpp-BIAN ligand in its neutral form.
5
The nickel atom in 5 is h -coordinated by the Cp ring in a quite
symmetric fashion since the Ni–C(Cp) distances lie in the narrow
˚
range of 2.160(1)–2.184(1) A. Together with N(1)–C(1)–C(2)–N(2)
Fig. 3 Molecular structure of complex 4. Hydrogen atoms are omitted.
the nickel atom forms an almost perfect plane, which is orthogonal
to the plane of the Cp-ring. Compared to free dpp-BIAN (1), the
C–N bond distances within the metallacycle are elongated while
the C–C bond is shortened (5, (C(1)–N(1) 1.312(1), C(2)–N(2)
Thermal ellipsoids are drawn at 30% probability.
˚
1.314(1) and C(1)–C(2) 1.4491(17) A; 1 cf. above), a situation,
which might be interpreted in the sense of a radical anionic nature
of the dpp-BIAN ligand.18 In (dpp-BIAN)Zn–Zn(dpp-BIAN),
which contains two dpp-BIAN radical-anions, the C(1)–N(1) and
14
˚
C(2)–N(2) distances are 1.324(1) and 1.336(1) A). However, the
ESR spectrum of 5 indicates the presence of Ni(I) and shows no
signal attributable to an dpp-BIAN radical-anion. Therefore, the
elongation of the C–N distances in 5 compared to those in free
dpp-BIAN may be interpreted by a strong back donation from the
electron-rich Ni(I) centre to the dpp-BIAN p orbitals.
The molecular structure of 5 can be compared with that of
the related complex (2,2¢-bipy)NiCp.21 Whereas the lengths of the
˚
Ni–N bonds in 5 (1.951(1), 1.953(1) A) and in (2,2¢-bipy)NiCp
˚
(1.955(3), 1.958 (4) A) are very similar, the Ni–C(Cp) distances
˚
are shorter in 5 (1.951(1)–1.953(1) A) than in (2,2¢-bipy)NiCp
˚
(2.17(4)–2.22(4) A), thus indicating a stronger electron back
donation of the metal to the dpp-BIAN ligand than to the 2,2¢-bipy
ligand.
In contrast to complex 4, in which the molybdenum atom
is coordinated by the two imino nitrogen atoms of the
Fig. 4 Molecular structure of complex 5. Hydrogen atoms are omitted.
Thermal ellipsoids are drawn at 50% probability.
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 4689–4694 | 4691
©

View Online
Table 1 Crystal structure data for 3, 4, 5 and 6
3
4a
5
6
Formula
C40H40MoN2O4
708.68
150(2)
C22H24MoN2O4Si2
532.55
150(2)
0.31 ¥ 0.07 ¥ 0.06
Orthorhombic
P212121
6.8006(2)
16.5995(3)
20.8751(5)
90
90
90
2356.5(1)
4
1.501
0.71073
1088
-8 ≤ h ≤ 8
-19 ≤ k ≤ 19
-22 ≤ l ≤ 24
3.14–25.00
99.7
C41H45N2Ni·0.5C6H14
667.57
296(2)
C44H48N2NiP2Si2
781.67
100(2)
0.20 ¥ 0.05 ¥ 0.05
Monoclinic
P21/c
17.7917(5)
14.5028(4)
17.5770(5)
90
118.579(1)
90
3982.8(1)
4
1.304
0.71073
Mr/g mol-1
T/K
Crystal size/mm3
Crystal system
Space group
0.24 ¥ 0.21 ¥ 0.13
Monoclinic
P21/c
21.1081(4)
20.0378(3)
18.0358(4)
90
106.820(2)
90
7302.1(3)
8
1.289
0.71073
2944
-25 ≤ h ≤ 25
-23 ≤ k ≤ 22
-18 ≤ l ≤ 21
2.86–25.00
99.8
0.23 ¥ 0.18 ¥ 0.17
Triclinic
¯
P1
˚
a/A
12.3259(12)
12.5980(13)
13.4184(13)
69.714(4)
78.287(3)
79.081(4)
1897.6(3)
2
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
3
˚
V/A
Z
D
calcd/g cm-3
1.168
0.71073
716
m(MoKa)/cm-1
F(000)/e
hkl range
1648
-16 ≤ h ≤ 16
-17 ≤ k ≤ 17
-18 ≤ l ≤ 18
1.64–29.00
—
99.1
0.913 and 0.885
20 427
-21 ≤ h ≤ 21
-17 ≤ k ≤ 17
-20 ≤ l ≤ 20
2.61–25.00
99.8
q Range for data collection/◦
Completeness to q = 25.00◦ (%)
Completeness to q = 29.00◦ (%)
Max. and min. transmission
Reflections measured
Reflections unique
—
—
—
0.9498 and 0.9100
74 675
12 838
0.9598 and 0.8149
22 311
4140
0.9677 and 0.8791
31 225
7005
9999
Rint.
0.092
863
0.0461/0.0748
0.0997/0.0864
0.980
0.0601
286
0.0305/0.0469
0.0394/0.0487
0.969
0.023
433
0.0336/0.0862
0.0402/0.0901
1.018
0.0633
466
0.0450/0.0956
0.0684/0.1031
1.031
Parameters refined
R(F)/wR(F2) [I > 2s(I)]
R(F)/wR(F2) [all data]
GOF (F2)
-3
˚
Drfin (max/min)/e A
0.394/-0.626
0.255/-0.244
0.512/-0.456
0.572/-0.293
a Flack parameter 0.04(3).
tms-BIAN ligand, in complex 6 the nickel atom is coordinated to
=
the C N double bond of only one of the two imino functions of
◦
˚
Table 2 Selected bond lengths (A) and angles ( ) for 3, 4, 5 and 6 with
the ligand. According to the dihedral angles C(5)–C(1)–N(1)–Ni
(99.9◦) and C(2)–C(1)–N(1)–Ni (97.5◦), the plane C(1)–Ni–N(1) is
orthogonal to the plane C(2)–C(1)–C(5). Besides the coordination
by the tms-BIAN ligand in this uncommon fashion, the nickel
atom is coordinated by the two phosphorous atoms of the dppe
ligand. The Ni–P bonds are of almost equal length (Ni(1)–P(1)
estimated standard deviations in parentheses
Complex
3
4
5
6
˚
Distances/A
M = Mo
M = Mo
M = Ni
M = Ni
M–N(1)
M–N(2)
M–C(1)
2.242(3)
2.246(3)
—
2.283(2)
2.277(3)
—
—
—
—
—
—
—
1.9528(10)
1.9506(10)
—
1.8976(17)
—
1.9856(19)
2.1708(6)
˚
2.1710(6) and Ni(1)–P(2) 2.1867(6) A). Whereas P(1) lies nearly
perfect in the N(1)–C(1)–Ni plane (dihedral angle P(1)–C(1)–
N(1)–Ni: 3.3◦), P(2) deviates noticeably from this plane (P(2)–
C(1)–N(1)–Ni: 10.0◦). The sum of the bond angles at the Ni
atom is 360.2◦. Complex 6 can be considered either as a Ni(II)
containing metallocycloazapropane or as a Ni(0) complex p-
coordinated by the C N double bond of the ligand. The latter
model seems to be more plausible, since the Ni–P distances
in 6 are larger than in the Ni(II) complex (dppe)NiCl2 (Ni–
M–P(1)
—
—
M–P(2)
—
—
2.1865(5)
—
—
—
—
—
—
—
—
—
1.363(2)
1.279(2)
1.510(2)
M–C(37)
M–C(38)
M–C(39)
M–C(40)
M–C(41)
M–C(19)
M–C(20)
M–C(21)
M–C(22)
C(1)–N(1)
C(2)–N(2)
C(1)–C(2)
1.963(4)
1.971(4)
2.051(4)
2.023(4)
—
—
—
—
—
1.293(4)
1.300(4)
1.480(5)
2.1675(14)
2.1757(14)
2.1847(13)
2.1609(14)
2.1688(14)
—
=
—
2.014(4)
2.064(4)
1.953(4)
1.953(4)
1.294(4)
1.299(4)
1.514(4)
25
—
—
—
˚
P 2.154(4) and 2.153(4) A). The Ni–P distances in 6 can be
further compared with those in (dppe)2Ni26 (Ni–P 2.152(3)–
1.3125(16)
1.3141(15)
1.4491(16)
27
˚
2.177(3) A) and in the monoazadiene complex (MAD)Ni(PPh3)2
i
˚
=
=
(MAD = PhCH CHCH NPr ) (Ni–P 2.195(1) and 2.192(5) A).
Concerning the last mentioned compound it has to be noted,
Angles/◦
=
that the nickel atom is not coordinated to the C N, but to
=
the C C double bond of the MAD ligand. A comparison of
N(1)–M–N(2)
N(1)–M–C(1)
72.70(10)
—
74.25(8)
—
83.13(4)
—
—
41.03(7)
the distances of the nickel atoms to the carbon atoms of the
=
=
respective coordinating C N and C C double bond reveals, that
4692 | Dalton Trans., 2009, 4689–4694
This journal is The Royal Society of Chemistry 2009
©

View Online
˚
(200 MHz, C6D6) d/ppm: 7.28–7.11 (m, 6 Harom.), 7.07 (d, 2 Harom.,
the distance Ni–C(1) (1.985(2) A) in 6 is close to the Ni–C bond
27
˚
8.3 Hz), 6.61 (dd, 2 Harom., 7.3 and 8.3 Hz), 6.35 (d, 2 Harom., 7.3 Hz),
3.50 (sept, 4 H, CHMe2, 6.8 Hz), 1.50 (d, 12 H, CH(CH3)2, 6.8 Hz),
0.8 (d, 12 H, CH(CH3)2, 6.8 Hz). IR (Nujol, cm-1): n = 2007 vs,
1898 vs, 1859 s, 1602 w, 1535 w, 1294 m, 844 w, 831 w, 804 w,
777 m, 762 m, 641 s, 572 m, 532 m, 505 m.
lengths in (MAD)Ni(PPh3)2 (2.013(4) and 2.005(4) A). In 6 the
Ni–C(1) bond (1.985(2) A) is larger than the Ni–N(1) distance
(1.898(1) A). Also the bonds N(1)–C(1) (1.361(3) A) and N(2)–
C(2) (1.279(2) A) differ significantly between each other, with the
˚
˚
˚
˚
=
latter value being in the range of the C N bond distances in free
tms-BIAN.22
Two further features of complex 6 are remarkable. The unit cell
of 6 contains two mirror isomers: in one the Ni atom is positioned
left from the plane running the middle of the C(1)–C(2) bond and
atom C(4) whereas in the other one the Ni atom is positioned on
the opposite side of this plane. However, the NMR spectroscopic
data of 6 suggest the presence of the symmetric molecule with
two equivalent imino functions in solution. We suppose that in
solution the fragment Ni(dppe) migrates fast (on the NMR time
1,2-Bis[(trimethylsilyl)imono]acenaphthene-molybdenumtetra-
carbonyl (tms-BIAN)Mo(CO)4 (4). To a solution of tms-BIAN
(0.30 g, 0.9 mmol) in toluene (20 mL) Mo(CO)6 0.24 g (0.91 mmol)
was added. Within 10 h of reflux, the reaction mixture changed
colour from orange to deep blue. Slow cooling of the reaction
mixture to ambient temperature causes precipitation of 4 as deep
blue crystals. Yield 0.33 g (68%). M.p. 210 ◦C. Anal. calcd for
1
C22H24MoN2O4Si2: C 49.62, H 4.54; found: C 50.43, H 5.12. H
=
scale) between two C N bonds. Furthermore, the molecules of
NMR (200 MHz, C6D6) d/ppm: 7.61 (d, 2 Harom., 7.3 Hz), 7.35 (d,
2 Harom., 8.3 MHz), 7.01 (dd, 2 Harom., 7.3 and 8.3 Hz), 0.61 (s, 18 H,
Si(CH3)3). IR (Nujol, cm-1): n = 2008 s, 1873 s, 1838 s, 1584 m,
1522 w, 1419 w, 1377 m, 1272 w, 1253 m, 1180 w, 1095 m, 1042 m,
930 m, 838 s, 826 s, 780 m, 676 w, 630 w, 599 w, 580 w, 549 w,
526 w.
complex 6 show p-stacking between the phenyl ring [C(19)–C(24)]
of the dppe ligand and the co-planar naphthalene part of the
tms-BIAN ligand. The atoms C(19), C(21) and C(23) are located
exactly above the atoms C(4), C(8) and C(10), respectively, and
˚
˚
the distances C(4) ◊ ◊ ◊ C(19) (3.422 A), C(8) ◊ ◊ ◊ C(21) (3.380 A),
˚
and C(10) ◊ ◊ ◊ C(23) (3.436 A) are comparable with the interlayer
28
˚
distance in graphite (3.35 A).
1,2-Bis[(2,6-diisopropylphenyl)imino]acenaphthene-nickelcyclo-
pentadienyl (dpp-BIAN)NiCp·0.5 C6H14 (5). To a solution of
dpp-BIAN (0.50 g, 1.0 mmol) in toluene (50 mL) [CpNi(CO)]2
(0.15 g, 0.5 mmol) was added. The reaction mixture was refluxed
until its colour turned bright green (ca. 1 h). Evaporation of the
solvent and crystallization of the crude product from hexane gave 5
as deep green crystals. Yield 0.59 g (89%). M.p. 240–245 ◦C. Anal.
calcd for C44H52N2Ni: C 79.17, H 7.85; found: C 78.87, H 7.63.
IR (Nujol, cm-1): n = 1650 w, 1529 s, 1511 m, 1418 m, 1363 w,
1330 m, 1309 m, 1257 m, 1191 w, 1112 w, 1003 w, 831 m, 783 s,
760 m, 550 w. ESR (toluene, 120 K): g1 = 2.183, g2 = 2.109, g3 =
1.993, A2 = 0.98 mT, A3 = 1.30 mT.
Conclusions
The mononuclear molybdenum and nickel complexes 3–6 with two
different acenaphthene-1,2-diimine ligands have been synthesised
either by ligand substitution reactions using appropriate metal
carbonyl complexes and free BIAN ligands (3–5), or by metathesis
between NiCl2(dppe) and Li2(tms-BIAN) (6). In all four complexes
the respective BIAN ligand acts as a neutral N- (3–5) or p donor
(6). The NMR data of 6 suggest a fast migration of the Ni(dppe)
=
fragment between the two C N double bonds of the tms-BIAN
ligand.
1,2-Bis[(trimethylsilyl)imino]acenaphthenenickel[1,2-bis(diphe-
nylphosphino)ethane (tms-BIAN)Ni(Ph2PCH2)2 (6). A mixture
of lithium (0.30 g, 43.2 mmol) and tms-BIAN (0.32 g, 1.0 mmol)
in toluene (50 mL) was vigorously stirred at room temperature for
4 h. The deep blue solution of [(tms-Bian)Li2]2 was then decanted
from excess lithium. NiCl2(dppe) (0.53 g, 1.0 mmol) was added
to this solution. The reaction mixture turned red brown within
4 h stirring. After evaporation of the solvent, the residue was
dissolved in hexane and filtered off from lithium chloride. Complex
6 was separated from the concentrated hexane solution as deep red
crystals. Yield 0.45 g (58%). M.p. >240 C (decomposition). H
NMR (400 MHz, C6D6) d/ppm: 7.94–7.89 (m, 4 H, C6H5-P), 7.53
(d, 2 Harom., 7.0 Hz), 7.35 (d, 2 Harom., 8.0 Hz), 7.24–7.19 (m, 6 H,
C6H5-P), 7.13–7.10 (m, 2 Harom.), 6.92–6.85 (m, 4 H, C6H5-P), 6.83
(d, 2 H, C6H5-P, 7.0 Hz), 6.78–6.75 (m, 4 H, C6H5-P), 1.92–1.88 (m,
2 H, CH2-P), 1.65–1.61 (m, 2 H, CH2-P), 0.39 (s, 18 H, Si(CH3)3).
29Si NMR (400 MHz, C6D6) d/ppm: 5.33 (s, 2 Si, Si(CH3)3). 31P
NMR (400 MHz, C6D6) d/ppm: 21.5 (d, 1 P, C6H5-P, 14.7 Hz),
18.1 (d, 1 P, C6H5-P, 14.7 Hz). IR (Nujol, cm-1): n = 3046 w,
1646 s, 1619 m, 1603 w, 1484 w, 1434 s, 1407 s, 1360 m, 1303 w,
1261 m, 1242 s, 1203 w, 1095 s, 1049 m, 1026 m, 1007 w, 972 m,
903 m, 846 s, 826 s, 776 m, 749 m, 699 s, 684 s, 676 m, 618 w, 526 s,
480 m.
Experimental
General procedures
All manipulations were carried out using Schlenk techniques.
tms-BIAN21 and dpp-BIAN29 have been prepared according to
literature procedures. Melting points were measured in sealed
capillaries and are uncorrected. The solvents were distilled
from sodium-benzophenone prior to use. The 1H, 29Si and
31P NMR spectra were recorded on Bruker DPX-200 NMR
and Bruker Advance III 400 spectrometers; IR spectra on
a FSM-1201 spectrometer; ESR spectra on a Bruker EMX
instrument.
◦
1
1,2-Bis[(2,6-diisopropylphenyl)imino]acenaphthene-molybde-
numtetracarbonyl (dpp-BIAN)Mo(CO)4 (3). To a solution of
dpp-BIAN (0.50 g, 1.0 mmol) in toluene (50 mL) Mo(CO)6
(0.26 g, 1.0 mmol) was added. Within 12 h of reflux, the mixture
changed colour from orange to bright green. The solvent was
then evaporated under vacuum. Crystallization of the residual
solid from hexane gave 0.55 g (78%) of complex 3 as deep
green crystals. M.p. 275–280 ◦C (decomposition). Anal. calcd for
C40H40MoN2O4: C 67.79, H 5.69; found: C 68.47, H 5.72. 1H NMR
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 4689–4694 | 4693
©

View Online
X-Ray structure determination
10 J. C. Alonso, P. Neves, M. J. P. da Silva, S. Quintal, P. D. Vaz, C. Silva,
A. A. Valente, P. Ferreira, M. J. Calhorda, V. Felix and M. G. B. Drew,
Organometallics, 2007, 26, 5548.
11 I. L. Fedushkin, A. A. Skatova, V. A. Chudakova and G. K. Fukin,
Angew. Chem., Int. Ed., 2003, 42, 3294.
12 (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, N. M. Khvoinova, A. A. Skatova and G. K. Fukin, Angew.
Chem., Int. Ed., 2003, 42, 5223; (c) I. L. Fedushkin, A. A. Skatova,
V. K. Cherkasov, V. A. Chudakova, S. Dechert, M. Hummert and H.
Schumann, Chem.–Eur. J., 2003, 9, 5778; (d) I. L. Fedushkin, A. G.
Morozov, O. V. Rassadin and G. K. Fukin, Chem.–Eur. J., 2005, 11,
5749; (e) I. L. Fedushkin, V. M. Makarov, E. C. E. Rosenthal and
G. K. Fukin, Eur. J. Inorg. Chem., 2006, 827; (f) I. L. Fedushkin, A. G.
Morozov, M. Hummert and H. Schumann, Eur. J. Inorg. Chem., 2008,
1584.
The intensity data for 3 and 4 were collected at 150 K on
an Oxford Diffraction Xcalibur S Sapphire diffractometer, for
5 and 6 at 296 and 100 K, respectively, on a Bruker APEX
I CCD diffractometer using graphite-monochromated Mo Ka
30
˚
(l = 0.71073 A) radiation. SADABS was used to perform area-
detector scaling and absorption corrections. The structures were
solved by direct methods using SHELXS-9731 and by full-matrix
least squares techniques against Fo2 using SHELXL-97.32 All non-
hydrogen atoms were refined anisotropically. The hydrogen atoms
were placed in calculated positions and assigned to an isotropic
displacement parameter of 0.08 A . Experimental details are given
2
˚
13 (a) H. Schumann, M. Hummert, A. N. Lukoyanov and I. L. Fedushkin,
Organometallics, 2005, 24, 3891; (b) A. N. Lukoyanov, I. L. Fedushkin,
H. Schumann and M. Hummert, Z. Anorg. Allg. Chem., 2006, 632,
1471; (c) A. N. Lukoyanov, I. L. Fedushkin, M. Hummert and H.
Schumann, Russ. Chem. Bull., 2006, 55, 422; (d) H. Schumann, M.
Hummert, A. N. Lukoyanov and I. L. Fedushkin, Chem.–Eur. J., 2007,
13, 4216; (e) I. L. Fedushkin, A. N. Lukoyanov, M. Hummert and H.
Schumann, Russ. Chem. Bull., 2007, 56, 1765.
14 I. L. Fedushkin, A. A. Skatova, S. Y. Ketkov, O. V. Eremenko, A. V.
Piskunov and G. K. Fukin, Angew. Chem., Int. Ed., 2007, 46, 4302.
15 I. L. Fedushkin, A. N. Lukoyanov, S. Y. Ketkov, M. Hummert and H.
Schumann, Chem.–Eur. J., 2007, 13, 7050.
in Table 1.
Acknowledgements
This work was supported by the Russian Foundation for Basic
Research (grant no. 07-03-00545), the Alexander von Humboldt
Foundation (Partnership project TU Berlin-IOMC RAS) and the
Fonds der Chemischen Industrie.
16 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.
17 I. L. Fedushkin, N. M. Khvoinova, A. Yu. Baurin, G. K. Fukin, V. K.
Cherkasov and M. P. Bubnov, Inorg. Chem., 2004, 43, 7807.
18 N. J. Hill, I. Vargas-Baca and A. H. Cowley, Dalton Trans., 2009, 240.
19 M. M. Khusniyarov, K. Harms, O. Burghaus and J. Sundermeyer,
Eur. J. Inorg. Chem., 2006, 2985.
20 I. L. Fedushkin, V. A. Chudakova, G. K. Fukin, S. Dechert, M.
Hummert and H. Schumann, Russ. Chem. Bull., 2004, 2744.
21 E. K. Barefield, D. A. Krost, D. S. Edwards, D. G. Van Derveer, R. L.
Trytko, S. P. O’Rear and A. N. Williamson, J. Am. Chem. Soc., 1981,
103, 6219.
22 I. L. Fedushkin, N. M. Khvoinova, A. V. Piskunov, G. K. Fukin, M.
Hummert and H. Schumann, Russ. Chem. Bull., 2006, 722.
23 P. N. W. Baxter, J. A. Connor, J. D. Wallis and D. C. Povey, J. Organomet.
Chem., 1992, 426, 187.
24 I. L. Fedushkin, N. M. Khvoinova, A. Yu. Baurin, V. A. Chudakova,
A. A. Skatova, V. K. Cherkasov, G. K. Fukin and E. V. Baranov, Russ.
Chem. Bull., 2006, 74.
25 R. Busby, M. B. Hursthouse, P. S. Jarrett, C. W. Lehmann, K. M. Abdul
Malik and C. Phillips, J. Chem. Soc., Dalton Trans., 1993, 3767.
26 H. Hartung, U. Baumeister, B. Walther and M. Maschmeier, Z. Anorg.
Allg. Chem., 1989, 578, 177.
Notes and references
1 (a) I. Matei, T. Lixandru and E. Comanita, Bul. Inst. Politeh. Iasi, 1960,
6, 171; (b) I. Matei, T. Lixandru and E. Comanita, Acad. Repub. Pop.
Rom. Fil. Iasi, Stud. Cercet. Stiint. Chim., 1960, 11, 281; (c) I. Matei
and T. Lixandru, Bul. Inst. Politeh. Iasi., 1967, 13, 245.
2 M. Dvolaitzky, C. R. Acad. Sci. Ser. C, 1969, 268, 1811.
3 L. Maresca, G. Natile and L. Cattalini, Inorg. Chim. Acta, 1975, 14,
79.
4 M. W. van Laren and C. J. Elsevier, Angew. Chem., Int. Ed., 1999, 38,
3715.
5 (a) R. van Belzen, H. Hoffmann and C. J. Elsevier, Angew. Chem., Int.
Ed. Engl., 1997, 36, 1743; (b) G. A. Grasa, R. Singh, E. D. Stevens and
S. P. Nolan, J. Organomet. Chem., 2003, 687, 269.
6 A. Heumann, L. Giordano and A. Tenaglia, Tetrahedron Lett., 2003,
44, 1515.
7 (a) A. E. Cherian, E. B. Lobkovsky and G. W. Coates, Chem. Commun.,
2003, 20, 2566; (b) F. Al-Abaidi, Z. Ye and S. Zhu, Macromol. Chem.
Phys., 2003, 204, 1653; (c) V. Fassina, C. Ramminger, M. Seferin,
R. S. Mauler, R. F. de Souza and A. L. Monteiro, Macromol. Rapid
Commun., 2003, 24, 667; (d) M. D. Leatherman, S. A. Svejda, L. K.
Johnson and M. Brookhart, J. Am. Chem. Soc., 2003, 125, 3068; (e) S. S.
Ivanchev, G. A. Tolstikov, V. K. Badaev, N. I. Ivancheva, I. I. Oleinik,
S. Ya. Khaikin and I. V. Oleinik, Vysokomol. Soedin. Ser. A, B, 2002,
44, 1478, (Polym. Sci. USSR Ser. A, B, 2002, 44, 931); (f) C. M. Killian,
D. J. Tempel, L. K. Johnson and M. Brookhart, J. Am. Chem. Soc.,
1996, 118, 11664; (g) C. Pellecchia, A. Zambelli, M. Mazzeo and D.
Pappalardo, J. Mol. Catal. A: Chem., 1998, 128, 229; (h) A. E. Cherian,
J. M. Rose, E. B. Lobkovsky and G. W. Coates, J. Am. Chem. Soc.,
2005, 127, 13770; (i) J. M. Rose, A. E. Cherian and G. W. Coates,
J. Am. Chem. Soc., 2006, 128, 4186.
27 C. Muller, L. Stamp and H. tom Dieck, J. Organomet. Chem., 1986,
308, 105.
28 L. A. Girifalco and R. A. Lad, J. Chem. Phys., 1956, 25, 693.
29 A. A. Paulovicova, U. El-Ayaan, K. Shibayama, T. Morita and Y.
Fukuda, Eur. J. Inorg. Chem., 2001, 2641.
30 G. M. Sheldrick, Empirical Absorption Correction Program, Universita¨t
Go¨ttingen, 1996.
8 I. Kim, J. M. Hwang, J. K. Lee, C. S. Ha and S. I. Woo, Macromol.
Rapid Commun., 2003, 24, 508.
9 L. K. Johnson, C. M. Killian and M. Brookhart, J. Am. Chem. Soc.,
1995, 117, 6414.
31 G. M. Sheldrick, Program for Crystal Structure Solution, Universita¨t
Go¨ttingen, 1990.
32 G. M. Sheldrick, Program for Crystal Structure Refinement, Universita¨t
Go¨ttingen, 1997.
4694 | Dalton Trans., 2009, 4689–4694
This journal is
The Royal Society of Chemistry 2009
©