Synthesis of cyclomanganated complexes derived from 2,5-diphenyl-1,3,4-oxadiazole and their reactivity with respect to 1,1-diphenyldiazomethane: Evidence for a fluxional trihaptobenzylic coordination mode

Article abstract of DOI:10.1016/j.jorganchem.2006.11.007

The cyclometallation of 2,5-diphenyl-1,3,4-oxadiazole with benzylpentacarbonylmanganese afforded the related mono- and binuclear complexes. The thermolytic coupling of 1,1-diphenyldiazomethane with monometallated 2,5-diphenyl-1,3,4-oxadiazole afforded substantial amounts of a new trihaptobenzylic complex. In the solid state, an X-ray diffraction analysis confirmed the coordination of manganese metal to one of the phenyl groups introduced by the 1,1-diphenyldiazomethane and to one of ligand's nitrogen centre. In solution, this trihaptobenzylic complex displays a fluxionality which is assumed to be related to the equilibration of its helical Λ and Δ enantiomers.

Full text of DOI:10.1016/j.jorganchem.2006.11.007

Journal of Organometallic Chemistry 692 (2007) 1092–1098
www.elsevier.com/locate/jorganchem
Synthesis of cyclomanganated complexes derived from
2,5-diphenyl-1,3,4-oxadiazole and their reactivity with respect
to 1,1-diphenyldiazomethane: Evidence for a fluxional
trihaptobenzylic coordination mode
a
a,
a
Christophe Michon , Jean-Pierre Djukic *, Michel Pfeffer ,
b
b,1
´
Nathalie Gruber-Kyritsakas , Andre de Cian
a
`
´ ´
Laboratoire de Syntheses Metallo-induites, Institut de Chimie, CNRS LC3 UMR 7177, Universite Louis Pasteur,
4, rue Blaise Pascal, 67070 Strasbourg Cedex, France
Service de De´termination Structurale, Institut de Chimie, CNRS LC3 UMR 7177, Universite´ Louis Pasteur,
4, rue Blaise Pascal, 67070 Strasbourg Cedex, France
b
Received 11 October 2006; received in revised form 2 November 2006; accepted 2 November 2006
Available online 12 November 2006
Abstract
The cyclometallation of 2,5-diphenyl-1,3,4-oxadiazole with benzylpentacarbonylmanganese afforded the related mono- and binu-
clear complexes. The thermolytic coupling of 1,1-diphenyldiazomethane with monometallated 2,5-diphenyl-1,3,4-oxadiazole afforded
substantial amounts of a new trihaptobenzylic complex. In the solid state, an X-ray diffraction analysis confirmed the coordination
of manganese metal to one of the phenyl groups introduced by the 1,1-diphenyldiazomethane and to one of ligand’s nitrogen centre.
In solution, this trihaptobenzylic complex displays a fluxionality which is assumed to be related to the equilibration of its helical K
and D enantiomers.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Manganese; Diazoalkane; Insertion; X-ray diffraction; Metallacycles
1. Introduction
tures in which the spin density generated at an
aromatic diazine core would be protected from external
chemical interactions by encapsulation within a rigid
and relatively electrochemically inert structure could
ensure to the material a high chemical stability, an essen-
tial feature for any intended applications as n-transport-
ing layers in organic semiconductors. In a previous
report [3], it was shown that electron-nest architectures
could readily be built by the thermolytic coupling of
bis-cyclomanganated heterocyclic derivatives, such as 1a,
with 1,1-diazoarylmethane leading to stable symmetric
manganese-scaffolded triple decker architectures, such as
1b (Eq. 1), exhibiting promising physicochemical proper-
ties [4,5].
It is well established that diaza-heterocycles, also
known as ‘‘diazines’’, display a reasonable electron affin-
ity, which stems from their low lying vacant p-orbitals
[1]. This intrinsic property is the base for the elaboration
of electron transporting polymers intended to be used in
organic semi-conducting devices [2]. As proposed previ-
ously, the elaboration of ‘‘electron nest-type’’ architec-
*
Corresponding author. Tel./fax: +33 390241523.
E-mail addresses: djukic@chimie.u-strasbg.fr (J.-P. Djukic), ser-
comrx@chimie.u-strasbg.fr (A. de Cian).
1
To whom requests pertaining to X-ray diffraction analyses should be
addressed.
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.11.007

C. Michon et al. / Journal of Organometallic Chemistry 692 (2007) 1092–1098
1093
lated complexes, i.e. compounds 2 and 3, were recovered
optimally, respectively, with 75% and 17% (Eq. 2).
ð1Þ
ð2Þ
In this note we disclose an evaluation of the use of 2,5-di-
phenyl-1,3,4-oxadiazole, a well known electroactive n-
transporting and fluorescent material [6], in the elaboration
of oxadiazole-based triple-decker architectures through an
investigation of its reaction with (g1-PhCH2)Mn(CO)5 and
the reactivity of its metallated derivatives towards Ph2CN2.
The relatively low yield in 3 may be reasonably related to
the peculiar steric cluttering expected in this bis-chelate.
Strong interactions arise from short distances between
Mn(CO)4 fragments. The analysis of a structure of 3
(Fig. 1) determined by X-ray diffraction study confirmed
the vicinity of the two equatorial carbonyl ligands, C(2)–
O(2) and C(2a)–O(2a) from manganese atoms Mn and
Mn(a) being separated by an interatomic distance
2. Results and discussion
2.1. Cyclomanganation of 2,5-diphenyl-1,3,4-oxadiazole with
(g1-PhCH2)Mn(CO)5
˚
O(2). . .O(2a) of 2.904(3) A. Such a steric hindrance confers
Ligand 2,5-diphenyl-1,3,4-oxadiazole was allowed to
react with 2.5 equiv. of (g1-benzyl)pentacarbonylmanga-
nese in refluxing heptane for 36 h. After separation by
chromatography over silica gel, the mono and bis-metal-
a helical character illustrated by a value of 8ꢁ for dihedral
angle Mn–N–N(a)–Mn(a). In the crystal lattice molecules
are p-stacked, in a perfect parallel manner [7], with a mean
˚
Fig. 1. (a) CSD-mercury diagram of the structure of 3, ellipsoids are drawn at the 30% probability level; selected distances (A), angles (ꢁ), and
torsion angles (ꢁ) (index ‘‘a’’ refers to symmetry-related atoms, which have not been numbered here for convenience): Mn–N, 2.113(1); Mn–C(11),
2.086(2); Mn–C(1), 1.868(2); Mn–C(2), 1.846(2); Mn–C(3), 1.795(2); Mn–C(4), 1.860(2); N–N(a), 1.413(2); O(2)–O(2a), 2.904(3); C(6)–C(5)–N–Mn,
4.4; C(5)–N–Mn–C(11), 6.3; N–C(5)–C(6)–C(11), 2.0; N–Mn–C(11)–C(6), 7.6; Mn–C(11)–C(6)–C(5), 7.5; O(5)–C(5)–C(6)–C(7), 4.7; Mn–N–N(a)–
Mn(a), 8.0; N(a)–N–Mn–C(2), 9.5; N–Mn–C(11), 79.59(5). (b) Space-filling diagram showing the contacts between vicinal Mn(CO)4 fragments. (c)
and (d) Side and top views of the molecular packing in the crystal lattice. Hydrogen atoms have been omitted for the sake of clarity.

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C. Michon et al. / Journal of Organometallic Chemistry 692 (2007) 1092–1098
inter-planar distance between the diphenyl-oxadiazolyl li-
gands amounting ca. 3.2 A.
probable generation of trihaptobenzylic species (mCO
2024, 2006, 1949, 1918 cmꢀ1), nothing but an air-sensitive
and oily material was recovered upon chromatographic
separation precluding further characterizations.
˚
The IR spectra of complexes 2 and 3 display four
bands (2 A1, 1 B1 and 1 B2) for the stretching vibrations
of the manganese carbonyl ligands. 13C NMR spectra of 2
and 3 display only three peaks for the four carbonyl
ligands at d 219.9, 213.4, 211.5 ppm (two axial CO
ligands) for 2 and at d 219.8, 214.3, 212.4 ppm (two axial
CO ligands) for 3. Such pattern is typical of cis-
L2Mn(CO)4 complexes as far as the metallacycle defines
a symmetry plane that leads to the equivalence of the
two axial carbonyl ligand.
ð3Þ
Nonetheless, refluxing complex 2 with Ph2CN2 in a (1/1)
heptane/toluene mixture led to a new trihaptobenzylic
complex 4, isolated as an orange solid, in 82% yield after
chromatographic purification (Eq. 4).
2.2. Thermolytic coupling with Ph2CN2
The reaction of complex 3 with Ph2CN2 (Eq. 3) proved
to be sluggish. Whereas IR spectra of crude mixtures
showed evidence of the diazoalkane consumption and
ð4Þ
The X-ray diffraction analysis of a crystal of 4 (Fig. 2) re-
vealed a quite unexpected coordination mode for the
Mn(CO)3 moiety. As opposed to other known pyridyl,
quinolyl and quinoxalyl trihaptobenzylic manganese com-
plexes, the phenyl ring comprising atoms C(19)–C(24) is
Fig. 2. (a) CSD-mercury diagram of the structure of 4, ellipsoids are drawn
at 50% probability level; disordered molecules of solvents and hydrogen
˚
atoms have been omittedfor the sake of clarity; selecteddistances (A), angles
(ꢁ), and torsion angles (ꢁ): Mn–N(1), 2.033(3); Mn–C(18), 2.165(3); Mn–
C(19), 2.275(3); Mn–C(24), 2.420(7); C(19)–C(20), 1.429(4); C(20)–C(21),
1.371(4); C(21)–C(22), 1.406(5); C(22)–C(23), 1.365(5); C(23)–C(24),
1.417(4); C(24)–C(19), 1.418(4); N(1)–N(2), 1.408(4); C(17)–C(18), 1.509
(4); C(18)–C(19), 1.479(4); C(20)–C(19), 1.429(4); C(19)–C(24), 1.418(4);
C(21)–C(20), 1.371(4);C(22)–C(21), 1.406(5); C(23)–C(22), 1.365(5);C(24)–
C(23), 1.417(4); (N(1),N(2),C(4),O(4),C(5))–(C(19),C(20),C(21),C(22),
C(23),C(24)), 3.900(7). C(17)–C(18)–C(19), 117.0(3); C(18)–Mn–C(19),
38.8(1); C(19)–Mn–C(24), 34.9(4). N(1)–C(5)–C(12)–C(17), 14.6; C(5)–
C(12)–C(17)–C(8), 0.8; C(12)–C(17)–C(18)–C(19), 56.7; C(17)–C(18)–
C(19)–C(20), 1.3. (b) Side view of the molecular packingin the crystal lattice.
Fig. 3. Variable temperature 1H NMR (500 MHz) experiments for 4 in
CDCl3.

C. Michon et al. / Journal of Organometallic Chemistry 692 (2007) 1092–1098
1095
not superimposed to the diazaoxazole ring but stands close
to it, in a shifted position and it is bonded to the Mn(CO)3
fragment in a g2 fashion. The manganese atom is also part
of a nearly planar 6-membered metallacycle comprising
atoms Mn, N(1), C(5), C(12), C(17) and C(18). The manga-
nese centre sits in a slightly distorted octahedral coordina-
tion geometry wherein the four equatorial positions are
occupied by atoms C(1), C(3), N(1) and C(24). Axial posi-
tions are occupied by atoms C(2) and C(18).
13C NMR spectrum of 4 at 263 K clearly displayed the
three peaks for carbonyl ligands (229.8, 221.3 and
219.3 ppm); other signals related to the ligand’s backbone
1
appeared between 163.6 and 66.4 ppm. H NMR experi-
ments at sub-ambient temperatures were necessary to over-
come dynamic effects for, at room temperature, the
spectrum was mostly unresolved and appeared as a com-
posite combination of broad signals and sharp multiplets
arising from protons Hx–Hz and Ha–Hd (Fig. 3). A
1H–1H COSY experiment carried out at 243 K, a tempera-
A standard decrease of the Mn-to-C interatomic
distance is observed for the manganese-benzylic fragment
following the order Mn–C(24) > Mn–C(19) > Mn–C(18).
Such pattern is frequently encountered with tricarbonyl-
manganese (g2; g1-benzyl) [8,9a] and (g3-allyl) [9b] com-
plexes. Interatomic distances C(20)–C(21) and C(22)–C(23)
are slightly shorter than C(19)–C(20) and C(21)–C(22),
suggesting thus a partial lift of conjugation as a result of
the coordination to the manganese in the g2 mode. It is
worthy to note that the packing scheme of the analyzed
crystal favours a perfectly parallel intermolecular p-stack-
ing of the phenyl-oxadiazolyl tails of compound 4 with
1
ture at which slow exchange rate was expected within H
NMR time scale, enabled a full assignment of the signals
(cf. Appendix A). The origin of the observed dynamic
behaviour was further investigated at 243 K by carrying
1
out a H–1H ROESY experiment (cf. Appendix A). This
established a clear connection between protons of the man-
ganese-bound p-coordinated phenyl group. For instance, it
was noticed that protons Ha and He, and Hb and Hd were
mutually correlated by intense cross-peaks revealing a
mutual exchange between these two ortho and two meta
positions. This mutual exchange most probably results
from a formal rotation of the g2 coordinated phenyl group,
a process which should involve two elementary steps
(Scheme 1): (1) the shift of the Mn(CO)3 moiety from a
g2–g1 to a g1 coordination mode, and (2) the rotation of
the phenyl group around the Cipso–Hc axis and its recoor-
dination. Moreover, it was noticed that the signals arising
from the exo-phenyl group (viz. H1–H5) also happened to
significantly broaden upon raising the temperature above
˚
an inter-annular distance amounting ca. 3.5 A. The unit
cell comprises two inversion centre-related molecules of 4
having opposite configurations and disordered molecules
of water and CH2Cl2.
The IR spectrum of complex 4 in solution displayed
three intense bands corresponding to the stretching vibra-
tions of the carbonyl ligands of the fac-Mn(CO)3 fragment
located in an asymmetric coordination environment. The
Scheme 1.

1096
C. Michon et al. / Journal of Organometallic Chemistry 692 (2007) 1092–1098
nation of the manganese in the early stages of the
metallation reaction or do not lead to ligand alteration
[12]. We have demonstrated here that the metallation of
2,5-diphenyl-1,3,4-oxadiazole with (g1-benzyl)pentacar-
bonylmanganese was effective although producing
a
mixture of mono- and binuclear complexes 2 and 3. The
yields and ratio of the latter products are deemed to be
mostly determined by steric entanglement. This result
somewhat complements the conclusions drawn by other
authors on the mono-palladation [13] and mono-iridation
[14] of oxadiazoles. In the light of the observations made
with 4, the failure of the thermolytic coupling of 1,1-diphe-
nyldiazomethane with 3 to produce a persistent and stable
dinuclear analog could be explained by a possible high flux-
ional character. Indeed, the coordinative hemilability of the
2,5-diphenyl-1,3,4-oxadiazolyl ligand, evidenced here with
4, could expose more critically the Mn centre to external
oxidizing agents as its coordination sphere would con-
stantly be partly unsaturated especially if molecular entan-
glement is marked. Nonetheless, this peculiar feature,
which seemingly precludes further use of oxadiazole-based
chelates in the elaboration of rigid triple-decker ‘‘electron
nests’’, might be of interest in homogeneous catalysis.
Fig. 4. Intra-annular angle w is defined by the interception of the lines
connecting the ring’s centroid to the carbon atom bound to the vicinal aryl
fragment and to the nitrogen atom bound to manganese.
243 K, which suggested a secondary exchange process. A
rationale for this would be the equilibration of the K and
D helical enantiomers of racemic 4 (Scheme 1), which
should be enabled by the partial de-coordination of the
Mn center evidenced above. This accounts reasonably for
the highly broadened signals observed at 283 K assigned
to the two benzylic carbon-bound phenyl groups. Unfortu-
nately, the ROESY experiment did not show cross peaks
connecting protons H1–H5 and Ha–He probably because
of the low exchange rate of this process at 243 K.
Worthy to note, a similar fluxional behaviour was
already observed in solution with two isomeric compounds
derived from 4,4-dimethyl-2-[(g6-4-tolyl)tricarbonylchro-
mium]-2-oxazoline, i.e. compounds 5a and 5b, which were
shown to interconvert readily in solution [10] (Eq. 5). It
was originally stated that the flexibility of the oxazolyl ring
could account for the propensity of the two isomers to
interconvert in solution.
4. Experimental
4.1. General
All experiments were carried out under a dry atmo-
sphere of argon with distilled, dry and degassed solvents.
2,5-Diphenyl-1,3,4-oxadiazole was purchase from Aldrich
Chem. Co. and used without further purification. 1,1-
Diphenyldiazomethane [15] was prepared by oxidation of
the corresponding hydrazone with yellow HgO at room
temperature. NMR spectra were acquired on Bruker
1
Avance 500 (13C and H nuclei) and AV 300 (1H nucleus)
spectrometers at room temperature unless otherwise stated.
Chemical shifts are reported in parts per million downfield
of Me4Si and coupling constants are expressed in Hz. IR
spectra were measured with a Perkin–Elmer FT spectrom-
eter. Mass spectra (FAB+) were recorded at the Service of
Mass Spectrometry of University Louis Pasteur and at the
Analytical Centre of the Chemical Institute of the Univer-
sity of Bonn (EI). Elemental analyses (reported in% mass)
were performed at the Service d’Analyses of the ‘‘Institut
de Chimie de Strasbourg’’ and at ‘‘Institut Charles
Sadron’’ in Strasbourg.
ð5Þ
We assume that the fluxionality reported here and in our
previous work is most probably a consequence of the geo-
metric features introduced by the oxazolyl and oxadiazolyl
ligands. Such five-membered ligands possess a large intra-
annular angle w (Fig. 4) of ca. 68ꢁ as compared to ca.
58ꢁ in pyridyl [8,10] and quinoxalyl related ligands [4],
which might contribute both in increasing the flexibility
and enabling the establishment of a nearly planar six-mem-
bered manganacycle as observed in 4 and 5b [10].
4.2. Procedure for X-ray diffraction analysis and structure
resolution for 3 and 4
3. Conclusion
Acquisition and processing parameters are provided in
Table 1. Reflections were collected with a Nonius Kappa
CCD diffractometer using Mo Ka graphite monochro-
Biscyclomanganated aromatic compounds are generally
readily accessible [4,11] by the thermolysis of alkylpenta-
carbonylmanganese compounds in the presence of an aro-
matic ligand whenever electronic properties of the host
ligand and steric hindrance do not preclude the pre-coordi-
˚
mated radiation (k = 0.71073 A). The structures of 3 and
4 were solved using direct methods, they were refined
against jFj and for all pertaining computations, the Nonius

C. Michon et al. / Journal of Organometallic Chemistry 692 (2007) 1092–1098
1097
Compound 2. HRMS (FAB+) calcd. for C18H9N2O5Mn:
387.989193. Found: 387.989193. MS (FAB+): m/z 388
(M)+, 361 (MH–CO)+, 332 (M–2CO)+, 304 (M–3CO)+.
Anal. calcd. for C18H9N2O5Mn: C, 55.69; H, 2.34; N,
7.22. Found: C, 55.33; H, 2.35; N, 7.22%. IR (KBr) mCO
Table 1
Table of acquisition and refinement parameters for structures 3 and 4
Compound
Formula
3
4
C22H8Mn2N2O9
2(C30H19MnN2O4)-
CH2Cl2H2O
1155.82
Triclinic
P1
8.8290(3)
10.1306(3)
16.1716(5)
92.107(5)
99.818(5)
99.515(5)
1402.50(7)
1
1
(cmꢀ1): 2082 (w), 1995 (s), 1990 (s), 1945 (m). H NMR
Molecular weight
Crystal system
Space group
554.19
Monoclinic
C 2/c
11.2799(2)
22.4877(6)
10.0822(2)
3
3
(CDCl3): d 8.11 (d, 2H, J = 6.3), 8.05 (d, 1H, J = 7.5),
7.78 (d, 1H, 3J = 7.7), 7.58 (m, 3H), 7.40 (t, 1H,
3J = 7.3), 7.25 (t*, 1H). 13C {1H} NMR (CDCl3): d 219.8
(CO), 214.3 (CO), 212.4 (2CO), 177.9, 170.9, 165.7, 142.5,
132.6, 131.8, 129.7, 129.4 (2C), 126.9 (2C), 125.1, 124.5,
123.1.
ꢀ
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
123.160(5)
3
˚
Compound 3: Anal. calcd. for C22H8N2O9Mn2: C,
47.68; H, 1.46; N, 5.05. Found: C, 47.57; H, 1.31; N,
5.06%. IR (KBr) mCO (cmꢀ1): 2087 (w), 2009 (s), 1998 (s),
1934 (m). 1H NMR (CDCl3): d 8.10 (d, 2H, 3J = 7.3),
V (A )
2140.9(1)
4
Yellow
Z
Color
Orange
Crystal dimension (mm)
0.14 · 0.10 · 0.08 0.20 · 0.20 · 0.14
1.72
1104
1.239
Dcalc (g cmꢀ3
F000
)
1.37
592
0.606
0.9240/1.0000
3
3
7.83 (d, 2H, J = 7.7), 7.45 (t, 2H, J = 7.4), 7.30 (t, 2H,
3J = 7.5). 13C {1H} NMR (CDCl3): d 219.9 (CO), 213.4
(CO), 211.5 (2 CO), 177.5, 171.2, 142.3, 132.5, 129.9,
125.9, 124.9.
l (mmꢀ1
)
Minimum and maximum
transmission
T (K)
0.835/0.985
173
173
Scan mode
hkl Limits
‘phi scans’
ꢀ15, 15/ꢀ28,
31/ꢀ14, 14
2.5/30.01
5670
‘phi scans’
0, 12/ꢀ14,
14/ꢀ22, 22
2.5/30.07
8162
4.4. Synthesis of complex 4, [10020020: g-20-(diphenyl-
methylene)-phenyl]-5-phenyl-1,3,4-oxadiazole-(jN)-
tricarbonylmanganese (I)
h Limits (ꢁ)
Number of data measured
Number of data
with I > 3r(I)
Number of variations
R
2328
5648
Complex 2 (0.153 g, 0.39 mmol) was dissolved in a mix-
ture of 5 mL of heptane and 5 mL toluene. The resulting
solution was brought to reflux under a stream of argon
and a solution of 1,1-diphenyldiazomethane (0.152 g, 0.78
mmol) in 2 mL toluene was added dropwise over 25 min.
The resulting mixture was heated for an additional period
of 35 min and cooled to room temperature. Solvents were
evaporated under reduced pressure and the raw mixture
separated by flash chromatography over silica gel/n-hexane
(6 ꢁC). A 6:4 mixture of n-hexane and dichloromethane
eluted a band containing 4, which was recovered as a mod-
erately air-sensitive orange solid (0.168 g, 0.32 mmol, 82%
yield) upon evaporation of the volatiles.
159
370
0.029
0.044
1.050
0.057
0.076
1.053
1.268
Rw
Goodness-of-fit
Largest peak in final difference 0.276
ꢀ3
˚
(e A
)
OpenMoleN package was used [16]. In structure 4, highly
disordered solvating molecules of CH2Cl2 and H2O were
not refined.
0
00
4.3. Synthesis of complex 3, [2,5-(diphenyl-jC2 ,jC2 )]-
HRMS (FAB+) calculated for C30H19N2O4Mn (M):
526.072525. Found: 526.072529. MS (FAB+): m/z 527
(MH)+, 470 (M–2CO)+, 442 (M–3CO)+, 387 (M–3CO–
Mn)+. Anal. calcd. for C30H19N2O4Mn: C, 68.58; H,
3.45; N, 5.33. Found: C, 67.57; H, 3.59; N, 5.26%. IR
(KBr) mCO (cmꢀ1): 2004 (vs), 1917 (s), 1892 (s). IR
(CH2Cl2) mCO (cmꢀ1): 2006 (vs), 1918 (s), 1906 (s). 1H
NMR (CDCl3, 233 K): d 8.05 (d, 1H, Ha, 3J = 7.8),
7.99 (d, 2H, Hx, 3J = 7.5), 7.90 (t, 1H, Hd, 3J = 7.5),
7.81 (d, 1H, H1, 3J = 7.8), 7.58 (t, 1H, Hz, 3J = 7.3),
7.51 (t, 2H, Hy, 3J = 7.6), 7.46 (t, 1H, Hb, 3J = 7.5),
7.40 (t, 1H, H2, 3J = 7.2), 7.36 (t, 1H, Hc, 3J = 7.5),
7.24 (d*, 1H, Hd), 7.11 (m, 3H, H3 + H4 + Hc), 7.05 (t,
1,3,4-oxadiazole-(jN1,jN2)bis(tetracarbonylman-
0
ganese(I)), and complex 2, [2,5-(phenyl-jC2 ,phenyl)]-
1,3,4-oxadiazole-(jN1)(tetracarbonylmanganese(I))
2,5-Diphenyl-1,3,4-oxadiazole (0.3 g, 1.35 mmol) and
benzylmanganesepentacarbonyl
1.2 equiv.) were refluxed in distilled n-heptane (15 mL) dur-
ing 12 h under a gentle stream of argon. An additional
(0.46 g,
1.61 mmol,
amount
of
benzylmanganesepentacarbonyl
(0.5 g,
1.75 mmol, 1.3 equiv.) was then added and the resulting
mixture was again refluxed for 24 h. After cooling to room
temperature, the solvent was removed under vacuum.
Chromatography on silica gel (40–63 lm) at 5 ꢁC allowed
to separate a yellow band containing complex 3 eluted with
a 9:1 mixture of n-hexane and dichloromethane (1 L)
(0.131 g, 0.236 mmol, 17% yield). A pale yellow band con-
taining complex 2 was eluted with a 8:2 mixture of n-hex-
ane and dichloromethane (0.395 g, 1.01 mmol, 75% yield).
3
1H, Hb, J = 7.5), 6.66 (d*, 2H, H5 + Ha), 6.12 (d, 1H,
3
He, J = 7.1). 13C {1H} NMR (CDCl3, 263 K): d 229.8,
221.3, 219.3, 163.6, 162.0, 150.0, 149.8, 136.7, 136.3,
132.6, 132.5, 132.4, 132.0, 129.2 (2C), 129.0, 127.9,
127.7, 127.6, 127.1 (2C), 126.4, 125.5, 125.0, 124.9,
122.1, 119.2, 116.3, 90.2, 66.4.

1098
C. Michon et al. / Journal of Organometallic Chemistry 692 (2007) 1092–1098
[5] (a) J.P. Djukic, C. Michon, Z. Ratkovic, N. Kyritsakas-Gruber, A.
de Cian, M. Pfeffer, Dalton Trans. (2006) 1564;
Acknowledgment
´
(b) Ph.D. Thesis, C. Michon, Universite Louis Pasteur, Strasbourg,
2003.
The authors gratefully acknowledge the CNRS for
financial support.
[6] (a) G. Laustriat, R. Voltz, Annal. Phys. Biol. Med. 3 (1969) 39;
(b) G.L. Smith, J.W. Rogers, J. Electrochem. Soc. 118 (1971)
1089;
Appendix A. Supplementary material
(c) C.P. Keszthelyi, A.J. Bard, J. Electrochem. Soc. 120 (1973)
241;
CCDC 623544 and 623545 contain the supplementary
crystallographic data for 3 and 4. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallo-
graphic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@
ccdc.cam.ac.uk. Supplementary data associated with article
can be found, in the online version, at doi:10.1016/
j.jorganchem.2006.11.007.
(d) Y. Kaminorz, B. Schulz, L. Brehmer, Synth. Met. 111–112
(2000) 75.
[7] B. Schulz, I. Orgzall, A. Freydank, C. Xu, Adv. Coll. Interface Sci.
116 (2005) 143.
[8] J.P. Djukic, K.H. Do¨tz, M. Pfeffer, A. de Cian, J. Fischer,
Organometallics 16 (1997) 5171.
[9] (a) L.S. Crocker, D.M. Heinekey, J. Am. Chem. Soc. 111 (1989)
405;
(b) G.J. Depree, L. Main, B.K. Nicholson, N.P. Robinson, G.B.
Jameson, J. Organomet. Chem. 691 (2006) 667.
[10] J.-P. Djukic, A. Maisse-Franc¸ois, M. Pfeffer, K.H. Do¨tz, A. de Cian,
J. Fischer, Organometallics 19 (2000) 5484.
[11] (a) N.P. Nicholson, L. Main, B.K. Nicholson, J. Organomet. Chem.
430 (1992) 79;
References
(b) J.M. Vila, M. Gayoso, M.T. Pereira, M. Lopez Torez, J.J.
Fernandez, A. Fernandez, J.M. Ortigueira, J. Organomet. Chem. 506
(1996) 165;
(c) J.P. Djukic, C. Michon, D. Heiser, N. Kyritsakas-Gruber, A. de
Cian, K.H. Do¨tz, M. Pfeffer, Eur. J. Inorg. Chem. (2004) 2107;
(d) W. Tully, L. Main, B.K. Nicholson, J. Organomet. Chem. 690
(2005) 3348.
[1] (a) R.S. Hay, P.J. Pomery, Aust. J. Chem. 25 (1972) 2597;
(b) W. Kaim, Angew. Chem., Int. Ed. Engl. 22 (1983) 171.
[2] (a) M.A. Petit, C. Clarisse, F. Templier, J. Electrochem. Soc. 140
(1993) 2498;
(b) T. Kanbara, T. Inoue, K. Sugiyama, T. Yamamoto, Synth. Met.
71 (1995) 2207;
(c) C. Giebeler, R.N. Marks, A. Bleyer, D.D.C. Bradley, S. Schrader,
Opt. Mater. 9 (1998) 99;
(d) M. Thelakkat, H.W. Schmidt, Polym. Adv. Technol. 9 (1998) 429;
(e) M.B. Casu, P. Imperia, S. Schrader, B. Falk, M. Jandke, P.
Strohriegl, Synth. Met. 124 (2001) 79;
[12] J.P. Djukic, A. de Cian, N. Kyritsakas-Gruber, J. Organomet. Chem.
690 (2005) 4822.
[13] F. Zamora, S. Rico, P. Amo-Ochoa, J. Inorg. Biochem. 68 (1997)
257.
[14] C. Qiu, S. Xiao, C.X. Qiu, U.S. Pat. Appl. Publ. (2006), US
2006036097 A1 20060216 and application US 2004-917474
20040813.
[15] L.I. Smith, K.L. Howard, Organic Syntheses Collective, vol. 3, Wiley,
New York, 1955, p. 351.
(f) A.P. Kulkarni, Y. Zhu, S.A. Jenekhe, Macromolecules 38 (2005)
1553.
[3] A. De Cian, J.P. Djukic, J. Fischer, M. Pfeffer, K.H. Do¨tz, Chem.
Commun. (2002) 638.
[4] C. Michon, J.P. Djukic, Z. Ratkovic, J.P. Collin, M. Pfeffer, A. de
Cian, J. Fischer, D. Heiser, K.H. Do¨tz, M. Nieger, Organometallics
21 (2002) 3519.
[16] C.K. Fair, in: MolEN: An Interactive Intelligent System for Crystal
Structure Analysis, Nonius, Delft, The Netherlands, 1990.