Synthesis and structure of new cationic methallyl molybdenum(II) complexes supported by α-diimine ligands

Article abstract of DOI:10.1016/j.poly.2008.11.050

Cationic complexes [Mo(η³-C₃H₄-Me-2)(N-N)(CO) ₃]⁺PF₆^-, {N-N = bipy (2); DAD (Ar-N{double bond, long}C(Me)-C(Me){double bond, long}N-Ar: Ar = o-Me-C₆H₄ (3),

Full text of DOI:10.1016/j.poly.2008.11.050

Polyhedron 28 (2009) 569–573
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis and structure of new cationic methallyl molybdenum(II)
complexes supported by
a-diimine ligands
Thouraya Turki a, Taha Guerfel b, Faouzi Bouachir a,
*
a Faculté des Sciences de Monastir, Laboratoire de Chimie de Coordination, Monastir 5000, Tunisia
b Laboratoire de Chimie de Solide, Faculte´ des Sciences de Monastir, 5000 Monastir, Tunisia
a r t i c l e i n f o
a b s t r a c t
ꢀ
Cationic complexes [Mo(g , {N–N = bipy (2); DAD (Ar–N@C(Me)–
3–C3H4–Me–2)(N–N)(CO)3]+PF6
Article history:
Received 21 May 2008
Accepted 21 November 2008
Available online 20 January 2009
C(Me)@N–Ar: Ar = o-Me–C6H4 (3), 2,6-Me2–C6H3 (4); Ar–BIAN (Ar = o-Me–C6H4 (5), Ar = iPr2–C6H3 (6)};
were synthesized by treating the compound Mo(CO)3(p-xylene) with the allyloxyphosphonium salt
in situ in presence of diimine ligand. Complex 4 was characterized by single crystal X-ray diffraction.
The solid state structure of the complexes revealed a preference for the more unsymmetrical axial isomer.
Ó 2008 Elsevier Ltd. All rights reserved.
Keywords:
Molybdenum
a-Diimine
Molybdenum(II) allylic complexes
Solid-state structure
1. Introduction
In the last few years, several new cationic allyl complexes of
palladium and nickel with
sized by our group [17]. We wish therefore to report new cationic
a-diimine ligands have been synthe-
Molybdenum(II) complexes of the type [Mo(g
3-C3H4)(CO)2-
(NCMe)2X] (X = halide or pseudohalide) have been used extensively
Mo(II) allyl complexes of general formula [Mo(
g
3-C3H4–
ꢀ
over several decades as synthetic precursors for a wide variety of
Me-2)(CO)3(N–N)]+PF6 with N–N as an
a-diimine ligands. The
Mo(II)-allyl derivatives containing the 12e-[Mo(CO)2-(
g
3-allyl)]+
solid state structure of the cation 4 (N–N = 2,6-Me2–C6H3–N@C(Me)–
C(Me)@N–C6H3–2,6-Me2) was determined at room temperature,
allowing the observation of the allyl geometry in great detail.
fragment which are formed by substitution of the labile nitrile li-
gands and/or the anion X [1]. It has been recently found that the
pseudooctahedral [MoX(CO)2(g3-allyl)(N–N)] (N–N = 2,20-bipyri-
dine, bipy; 1,10-phenanthroline, phen) complexes react with orga-
nolithium or organomagnesium reagents and with sodium
alkoxides to afford new alkyl [2], alkynyl [3] and alkoxo [4]
complexes by selective halide substitution. The same reaction with
2. Results and discussion
Allyl cꢀomplexes of the type [Mo(
g
3-C3H4–Me-2)(CO)3-
(N–N)]+PF6 (2–6) (N–N = bipy, Ar-BIAN [18], DAD [19]) can be
obtained successfully in high yields by an oxidative addition of
methallyloxyphosphonium [20] to the zerovalent compound Mo-
NaCN has provided access to the complexes [Mo(CN)(
(CO)2(N–N)] [5].
g
3-allyl)
The well known allyl complex [Mo(g
3-C3H4)(CO)2(NCMe)2X]
(CO)3(p-xylene) in tetrahydrofuran to produce the axial isomer
ꢀ
3-C3H4–Me-2)(CO)3(THF)2]+PF6 (1) whereas ‘‘equatorial”
has been shown as a useful precursor to prepare mononuclear
derivatives, used both as catalysts for polymerisation of certain
dienes [6] and in organic synthesis for allylic alkylations [7]. Their
cationic anologues, having the two nitriles replaced by a L–L ligand,
[Mo(g
isomers are found for halide analogues [21]. The reaction in situ
of compound 1 with the -diimine ligand in methylene chloride at
room temperature offered the cationic
3-methallyl molybdenum
complexes (2–6) supported by the -diimine ligands (Scheme 2).
a
g
for instance, always show a fac arrangement of the
g
3-C3H4 and
a
the two CO ligands and exhibit two isomers, B (equatorial) with
Cs symmetry and A (axial) without symmetry (Scheme 1).
Compounds 2–6, crystallized as red crystals for complex 2,
blue-purple for complexes 3–4 and green for complexes 5–6 from
CH2Cl2/n-hexane, and are soluble in methylene chloride, chloro-
form and acetonitrile but only sparingly soluble in diethylether.
They are stable at room temperature under an inert atmosphere;
however, significant decomposition can be observed at high tem-
perature. These compounds have been characterized by various
techniques including 1H, 13C, IR spectroscopy and the single crystal
X-ray structure determinations of the complex 4.
An increased interest in the chemistry of
their complexes [8–12] was stimulated by the recent discovery by
Brookhart and co-workers of Ni(II) and Pd(II) -olefin polymeriza-
tion catalyst containing bulky -diimine ligands [13–16].
a-diimine ligands and
a
a
* Corresponding author. Tel.: +216 98503997; fax: +216 71 704 329.
E-mail address: bouachirf@yahoo.de (F. Bouachir).
0277-5387/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2008.11.050

570
T. Turki et al. / Polyhedron 28 (2009) 569–573
+
+
L
X
CO
CO
CO
Mo
X
Mo
L
L
CO
L
B
A
Scheme 1.
The variation of the steric and electronic proprieties of
a-dii-
mine ligands is possible by changing the aromatic substituent on
the imine N atom. The new complexes exhibit spectroscopic data
in accord with the proposed structures. The formation of the allyl
complexes 2–6 is clear from the observed syn and anti allylic pro-
ton signals in the 1H NMR. These signals were attributed consider-
ing that in allyl complexes, the syn protons resonate at higher
frequencies than the anti protons [21,22]. Thus, the two resonances
are located, respectively, at 1.07, 1.72 and 1.97, 0.92 and 1.43 ppm
for Hanti and 1.23, 2.98, 2.58, 2.19 and 3.22 ppm for Hsyn for com-
plexes 2–6. In 13C NMR spectroscopy, the two terminal allylic car-
bons C1 and C3 appear at 61.6, 67.0, 69.0, 63.2 and 70.6 ppm,
respectively, for complexes 2–6. The C@N functions are shifted to
high frequency when compared to free ligands and appear at
172.1, 171.0, 176.0 and 168.6, for complexes 3–6, respectively.
Two carbonyl carbon signals are shown in the 13C NMR spectra.
The IR spectra are also instructive. The complexes 2–6 show in
IR spectroscopy a C@N stretching frequency in the region 1606–
1690 cmꢀ1, which is in agreement with those reported for other
Fig. 1. ORTEP diagram of 4.Thermal ellipsoids are drawn at the 50% probability
level. PF6 anion and hydrogen atoms have been omitted for the sake of clarity.
ꢀ
ing Scheme is shown in Fig. 1 with details of the structure determi-
nation, including unit-cell data, summarized in Table 1 and
relevant bond distances and angles in Table 2. The coordination
environment of the molybdenum center is pseudooctahedral with
two carbon atoms from the carbonyl groups and the centroid of the
allyl ligand determining a fac stereochemistry. The structure of
complex 4 consists of loosely associated [(g
3-C3H4–Me-2)Mo
(CO)3(N–N)]+ cation and octahedral PF6ꢀ counteranion without di-
rect interactions as appears from the large distance between the
0
metal and the nearest fluorine atom (Mo–F4 = 4.369 ÅA) which is
close to other cationic allyl complexes [17].
In complex 4 structure, the allyl ligand adopts the usual endo
conformation in the solid or in the solution state, with the open
side eclipsing the two carbonyls C26O2 and C27O3. The two nitro-
gen donors from the (N–N) fragment occupy an equatorial and an
axial coordination position (B in Scheme 2) which is in agreement
with those reported for other diimine complexes [21,22].
In all complexes, the remaining equatorial position is taken by a
a
-diimine complexes coordinated as an s-cis conformation
[18,23]. Moreover, complexes 2–6 exhibit the frequency of the cor-
responding counteranion. The
(PF6ꢀ) value is evident (843 cmꢀ1).
The IR data for 2–6 show two strong carbonyl bands of equal inten-
m
g
3-allyl]
carbonyl ligand. The a-diimine ligand is coordinated in a symmetric
sity, consistent with cis-carbonyl groups in the [Mo(CO)2(
moiety.
fashion as seen in Fig. 1, with Mo–N bond lengths of 2.213(7) and
0
2.267(9) ÅA which are very close to those reported for other related
A single crystal X-ray diffraction study confirms the identity of
complexes [21,22]. The N1–Mo–N2 angle of 70.8(3)° reflects a
complex 4. The molecular structure of 4 with the adopted number-
THF
Mo(CO)6
+
p-xylene
(p-xylene)Mo(CO)3
[Mo(CO)3(THF)3]
4
2
1
2
4
-THF
-
O-P+(NMe2)3 PF6
+
1
3
3
CO
OC
Mo
-
PF6
[Mo(CO)3(THF)2(η3-C4H7)]+PF6
-
N
N
N
CO
CH2Cl2
N
2-6
1
9
10
8
7
11
Me
Me
6
5
=
N
N
Ar
N
N Ar
Ar
N
N
Ar
N
N
2
3 (Ar = o-Me-C6H4)
5 (Ar = o-Me-C6H4)
4 (Ar = 2,6-Me2-C6H3) 6 (Ar = 2,6-iPr2-C6H3)
Scheme 2.

T. Turki et al. / Polyhedron 28 (2009) 569–573
571
nature of this ligand [24]. The o,o0-dimethylphenyl groups make
an angle of approximately 90° to the plane of the C@N bonds,
due to the presence of the o-methyl substituents, as appears from
the torsion angles of ꢀ82.5(13), 98.5(11), 100.2(12) and ꢀ80.4(13)
for C6–N2–C13–C18, C6–N2–C13–C14, C5–N1–C7–C12 and C5–
N1–C7–C8, respectively.
Table 1
Summary of crystallographic data and X-ray experimental details for 4.
Empirical formula
Formula weight
Crystal system
Space group
Z
C27H31F6MoN2O3P
672.45
monoclinic
P21/c
4
a (Å)
9.459(3)
b (Å)
19.113(5)
c (Å)
16.234(7)
90
3. Conclusion
a
(°)
b (°)
92.98(3)
90
2931.0(17)
1.524
p
-Allyldicarbonyl complexes of molybdenum and tungsten
formulated as [M(
3-allyl)X(CO)2L2] (M = Mo, W; X = halogen;
L = 2-electron donating molecule) have been extensively explored
[25], since [M(
3-allyl)(CO)2] fragment often plays a role of the
c
(°)
V (Å3)
g
qcalc (g cmꢀ3
)
Crystal dimension (mm)
Temperature (K)
Radiation, k (Å)
F(000)
2h range (°)
0.12 ꢁ 0.19ꢁ0.33
g
293(2)
key in the catalytic organic transformations [26]. From this point
of view, much effort has been made on the synthesis and reaction
of these compounds bearing various monodendate (2-electron
donor) and bidentate (4-electron donor) ligands [27].The nitrile
Mo, 0.71073
1368
1.65–27.13
Limiting indices
ꢀ12 6 h 6 12, ꢀ2 6 k 6 24, ꢀ20 6 l 6 2
No. of scanned reflections
No. of independent reflections
No. of observed reflections
No. of parameters varied
Absorption correction
Data reductions programs
Programs used
8879
6422
6422
354
complexes [Mo(g
3-C3H5)X(CO)2(NCMe)2] (X = halide) have been
shown to act as precursors in the ring-opening metathesis
polymerization of norbornene [28] and polymerization of terminal
acetylenes as well as catalyze the oligomerization of nPh(CC)nPh,
(n = 1, 2) [29]. Following these results, we prepared and
empirical (DIFABS)
XCAD4
SHELX-97
8.80, 21.75
0.960
characterized new complexes of the type [Mo(
g
3-C3H4–Me-2)-
R1(F0), wR2(F20) (I > 2
r(I)) (%)
ꢀ
(N–N)(CO)3]+PF6 (N–N =
a
-diimine).
Goodness-of-fit on F2
The X-ray structure of the complexes studied showed the pres-
ence of the equatorial-axial isomer, B in Scheme 1.
The synthetic procedure for preparing 2–6 complexes offers
Table 2
great versatility for the generation of other
a-diimine allyl com-
Bond lengths (Å) and angles (°) for 4.
plexes of possible catalytic interest. The application of these com-
pounds in catalytic reaction such as polymerisation of alkenes
(ethylene, styrene, etc.), functional alkenes (methyl acrylate) and
ring opening metathesis polymerisation of norbornene is currently
under study.
Mo–N1
Mo–C1
Mo–C3
N1–C5
N1–C7
Mo–C26
2.213(7)
2.344(10)
2.37(10)
1.289(13)
1.448(12)
1.960(13)
Mo–N2
Mo–C2
N2–C6
N2–C13
Mo–C25
Mo–C27
2.267(9)
2.302(11)
1.289(11)
1.468(11)
2.227(9)
1.857(16)
N1–Mo–N2
N1–Mo–C1
N1–Mo–C3
N1–Mo–C2
C2–Mo–C3
C1–Mo–C3
C5–N1–C7
C5–N1–Mo
C7–N1–Mo
70.8(13)
147.1(4)
152.2(4)
165.6(4)
34.0(5)
N2–Mo–C3
N2–Mo–C1
N2–Mo–C2
C1–Mo–C2
87.3(4)
137.9(3)
102.4(4)
35.9(4)
4. Experimental
4.1. General
60.1(4)
117.8(8)
119.9(6)
122.2(6)
C6–N2–C13
C6–N2–Mo
C13–N2–Mo
117.1(9)
118.6(6)
124.1(6)
All manipulations were carried out under an atmosphere of dry
argon using standard schlenk techniques. Diethyl ether was
distilled from sodium benzopheneone; methylene chloride and
hexane was distilled over P2O5. 2-Methylaniline, 2,6-diisopropyl-
aniline were distilled from potassium hydroxide prior to use.
Bipyridine (Bipy) and acenaphtenquinone were used as received
from commercial sources. p-xylene was purified via column on
slightly distorted pseudo-octahedral coordination sphere which is
identical to known values in the literature for other molybdenum
allyl complexes [21,22]. The metal chelate ring (Mo–N1–C5–C6–
N2) in complex 4 is almost flat as indicated by the torsion angles
of ꢀ2.7(16), 7.0(13) and ꢀ3.0(13)° for N1–C5–C6–N2, Mo–N2–
alumna.
a-diimine ligands were prepared according to literature
methods [18,19]. NMR spectra were recorded on a Bruker AMX
300 spectrometer. H and C chemical shifts were given in ppm
and referenced to the residual solvent resonance relative to TMS;
Hsyn and Hanti designate the syn- and the anti-H atoms, respec-
tively, of the allyl ligand. The atom labelling scheme for the allyl
complexes was shown below.
C6–C5 and Mo–N1–C5–C6, respectively. The allyl ligand is bonded
0
symmetrically to the molybdenum center (Mo–C1 = 2.344(10) ÅA
0
and Mo–C3 = 2.369(10) ÅA). We note that the Mo–C(allyl) distances
are reasonable for an allyl trans to a ligand of moderate trans influ-
ences. The methyl on the allyl group is in the same plane of the allyl
ligand as indicated by the torsion angle of 178.1° for C4–C2–C3–C1.
The geometric arrangement found for the studied complex can be
easily characterized by /, which is the angle between the Mo–
C25 with the line defined by the centroid of the allyl moiety and
the molybdenum with Mo–C25. This / parameter gives the orienta-
tion of the allyl fragment relative to the monodentate ligand and
determines unequivocally the position of the bidentate ligand in
the metal coordination sphere. Thus, in complex 4, the / angle takes
H
syn
H
anti
+
H
anti
H
syn
CO
CO
M o
N
N
an approximate value of 90° and the chelating of the
ligand occur via equatorial and axial sites.
The N1–C5, N2–C6 and C5–C6 bond distances of 1.289(13),
1.289(11) and 1.502(13) ÅA, respectively, confirm the conjugated
a-diimine
CO
0

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T. Turki et al. / Polyhedron 28 (2009) 569–573
4.2. General procedure for the preparation of [(
a-diimine)Mo(CO)3
0
127.2 (Cortho,ortho ); 128.7 (Cpara); 129.0 (Cmeta); 149.8 (Cipso); 171
ꢀ
(g
3-C3H4–Me-2)]+PF6 complexes
(C@N); 200, 207 (CO).
In an inert atmosphere, Mo(CO)6 compound (1 equiv.) was
4.2.4. Synthesis of [(oꢀ-CH3–C6H4–BIAN)Mo(CO)3
(g
3-C3H4–Me-2)]+PF6 (5)
dissolved in small amount of p-xylene and refluxed for 2 h.
Methallyloxyphosphonium [C4H7OP+(NMe2)3PF6ꢀ] was added to
the cold solution previously prepared in tetrahydrofuran. The
yellow solution was stirred at room temperature for 24 h. The sol-
vent was removed under vacuum to afford an oil compound which
Following the general procedure, from Mo(CO)6 (0.080 g,
0.3 mmol), p-xylene (5 ml), THF (15 ml), 2-methylallyloxyphos-
phonium (0.1 g, 0.26 mmol) and (o-CH3–C6H4–BIAN) (0.108 g,
0.3 mmol) was obtained 0.185 g of 5 as a green solid after crystal-
lization from a mixture (n-hexane/CH2Cl2: 8/2).
was dissolved in anhydrous CH2Cl2 and a
a-diimine ligand was
Yield 91%. IR [m
cmꢀ1] (KBr): 1638, 1690 (C@N); 1948, 1854
added. The solution was stirred at room temperature for 24 h. The
supernatant was separated by filtration through a Celite filter, and
the solvent was removed under vacuum to afford the oil complex.
This was washed with n-hexane (3 ꢁ 15 ml) and dried in vacuum.
The solid was crystallized from methylene chloride/ n-hexane
solution at room temperature. Yields ranged from 83% to 94%.
(CO); 840 (PF6ꢀ).
1H NMR (300 MHz, MeOD, 25 °C, d [ppm]): 0.92 (s, 2H, Hanti);
1.29 (s, 3H, H4); 2.19 (s, 2H, Hsyn); 2.39(s, 3H, o,o0-CH3); 2.69 (s,
3H, o,o0-CH3); 7.15–7.29 (m, 14H, 8Har + 6 H7,8,9).
13C NMR (75.5 MHz, MeOD, 25 °C, d [ppm]): 14.2 (o,o0-CH3);
0
22.7 (C4); 63.2 (C1,3); 71.6 (C2); 113.1 (Cortho ); 123.6 (C7); 127.1
0
ꢀ
(Cpara); 127.2 (Cortho); 127.6 (Cmeta ); 128.9 (C8); 129.7(C9); 129.9
4.2.1. Synthesis of [(Bipy)Mo(CO)3(
g
3-C3H4–Me-2)]+PF6 (2)
(C10); 130.3 (Cmeta); 131.5 (C6); 139.2 (C11); 148.1 (Cipso); 176
Following the general procedure, from Mo(CO)6 (0.080 g,
0.3 mmol), p-xylene (5 ml), THF (15 ml), 2-methylallyloxyphos-
phonium (0.1 g, 0.26 mmol) and Bipy. (0.049 mg, 0.31 mmol) was
obtained 0.188 g of 2 as a red solid after crystallization from a mix-
ture (n-hexane/CH2Cl2: 9/1).
(C@N); 203, 205 (CO).
4.2.5. Synthesis of [(2ꢀ,6-(iPr)2–C6H3–BIAN)Mo(CO)3
(g
3-C3H4–Me-2)]+PF6 (6)
Following the general procedure, from Mo(CO)6 (0.080 g,
Yield 91%: IR [
m
cmꢀ1] (KBr): 1606 (C@N); 1937, 1840 (CO); 848
(PF6ꢀ).
0.3 mmol), p-xylene (5 ml), THF (15 ml), 2-methylallyloxyphos-
phonium (0.1 g, 0.26 mmol) and (2,6-(iPr)2–C6H3–BIAN) (0.142 g,
0.3 mmol) was obtained 0.226 g of 6 as a green solid after crystal-
lization from a mixture (n-hexane/CH2Cl2:8/2).
1H NMR (300 MHz, CDCl3, 25 °C, d [ppm]): 1.02 (s, 3H, H4);
1.05–1.07 (d, 2H, Hanti, JHH = 6 Hz), 1,23 (s, 2H, Hsyn); 7.50–8.80
(m, 8H, bipy).
Yield 88%. 1H NMR (300 MHz, CDCl3, 25 °C, d [ppm]): 0.77–0.79
(d, 12 H, JHH = 6.6 Hz, CH3–iPr); 1.05–1.03 (d, 12H, JHH = 6.9 Hz,
CH3–iPr); 1.25 (s, 3H, H4); 1.43 (s, 2H, Hanti); 2.81–2.86 (sept, 4H,
JHH = 6,6 Hz, CH–iPr); 3.22 (s, 2H, Hsyn); 6.43–6.45 (d, 2H,
JHH = 7.2 Hz, H7); 7.07–7.37 (m, 6H, Har), 7.67–7.70 (d, 2H, H9,
J = 8.1 Hz).
13C NMR (75.5 MHz, CDCl3, 25 °C, d [ppm]): 19.7 (C4); 61.6
(C1,3), 81.9 (C2); 124.7, 126.9, 141.4, 151.3, 154.3 (bipy); 205, 208
(CO).
4.2.2. Synthesis of [(o-CH3–C6H4N@C(Me)–C(Me)@N–C6H4–o-CH3)
ꢀ
Mo(CO)3
(g
3-C3H4–Me-2)]+PF6 (3)
13C NMR (75.5 MHz, CDCl3, 25 °C, d [ppm]): 14.1 (C4); 23.7, 24.3,
25.0, 25.3, 25.7, 26.5 (CH3–iPr); 28.0, 28.5, 29.4, 29.7 (CH–iPr); 70.6
(C1,3); 75.1 (C2); 125.0 (C7); 125.3 (Cmeta); 125.7 (Cpara); 127.5 (C8);
128.1(C9); 128.6 (C6); 130.3 (C10); 139.5 (Cortho); 141.0(C11); 147.7
(Cipso); 168.6 (C@N); 203, 205 (CO).
Following the general procedure, from Mo(CO)6 (0.080 g,
0.3 mmol), p-xylene (5 ml), THF (15 ml), 2-methylallyloxyphos-
phonium (0.1 g, 0.26 mmol) and (o-CH3–C6H4N@C(Me)–C(Me)@N–
C6H4–o-CH3) (0.079 mg, 0.3 mmol) was obtained 0.180 g of 3 as a
blue-purple solid after crystallization from a mixture (n-hexane/
CH2Cl2: 8/2).
4.3. X-ray crystallographic study
Yield 93%. IR [
m
cmꢀ1] (KBr): 1608 (C@N); 1949, 1860 (CO); 846
(PF6ꢀ).
The X-ray crystallographic study of complex 4 is carried out on
a MACH3 Enraf Nonius diffractometer using monochromated Mo
1H NMR (300 MHz, CDCl3, 25 °C, d [ppm]): 1.18 (s, 6H, o-CH3);
1.57 (s, 3H, H4); 1.72 (s, 2H, Hanti); 2.14 (s, 3H, CH3–C@N); 2.31
(s, 3H, CH3–C@N); 2.98 (s, 2H, Hsyn); 7.01–7.38 (m, 8H, Har).
13C NMR (75.5 MHz, CDCl3, 25 °C, d [ppm]): 18.1 (o,o-CH3), 20.4
(o0,o0-CH3); 21.5, 26.9 (CH3–C@N); 30.1 (C4); 67.0 (C1,3); 71.0 (C2);
K
a
radiation (k = 0.71073 Å) at 293 K. Accurate unit cell parame-
ters and orientation matrix are determined from 25 reflections in
the range 13–15°. Intensity data are collected by using the –2h
scan mode with a range of 2 < h < 27°. All the intensity data are cor-
rected for Lorentz and polarization effects. The crystal structure
solution carried out with direct methods from the SHELXS-97 permit-
ted the location of all non-hydrogen atoms. After anisotropic least-
squares refinement, hydrogen atoms are placed at their geometri-
cally calculated positions and refined riding on the corresponding
atoms with isotropic thermal parameters. Final refinement based
x
0
0
104 (Cortho ); 121.1 (Cpara); 127.9 (Cortho); 128.1 (Cmeta ); 131.8
(Cmeta); 149.8 (Cipso); 172.1 (C@N); 204, 205 (CO).
4.2.3. Synthesis of [(2,6-(CH3)2–C6H3N@C(Me)–C(Me)@N–C6H3–2,6-
ꢀ
(CH3)2)Mo(CO)3
(g
3-C3H4–Me-2)]+PF6 (4)
Following the general procedure, from Mo(CO)6 (0.080 g,
0.3 mmol), p-xylene (5 ml), THF (15 ml), 2-methylallyloxyphos-
phonium (0.1 g, 0.26 mmol) and (2,6-(CH3)2–C6H3N@C(Me)–
C(Me)@N–C6H3–2,6-(CH3)2) (0.087 mg, 0.3 mmol) was obtained
0.190 g of 4 as a blue-purple solid after crystallization from a mix-
ture (n-hexane/CH2Cl2: 8/2).
on the reflections [I > 2r(I)] converged at R1 = 0.0880,
wR2 = 0.2175 and GoF = 0.960. The experimental conditions of data
collection, strategy followed for the structure determination, and
final results are given in Table 1.
Yield 94%. IR [
m
cmꢀ1] (KBr): 1622 (C@N); 1940, 1857 (CO); 843
(PF6ꢀ).
Appendix A. Supplementary data
1H NMR (300 MHz, CDCl3, 25 °C, d [ppm]): 1.25 (s, 6H, o,o0-CH3);
1.73 (s, 3H, H4); 1.97 (s, 2H, Hanti); 2.18 (s, 6H, o,o0-CH3); 2.24 (s,
6H, CH3–C@N); 2.58 (s, 2H, Hsyn); 7.00–7.26 (m, 6H, Har).
CCDC 276931 contains the supplementary crystallographic data
for this article. These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
13C NMR (75.5 MHz, CDCl3, 25 °C, d [ppm]): 17.5 (o,o-CH3), 18.6
(o0,o0-CH3); 20.2, 23.4 (CH3–C@N); 24.1 (C4); 69.0 (C1,3); 86.0 (C2);

T. Turki et al. / Polyhedron 28 (2009) 569–573
573
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UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.poly.2008.11.050.
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