The reactivity of molybdenum pentachloride with ester molecules: Ester activation, metal reduction, and synthesis of 1D coordination polymers

Article abstract of DOI:10.1002/ejic.201201217

The reactions of Mo₂Cl₁₀ (1) with stoichiometric amounts of a variety of molecules containing the ester functionality in anhydrous noncoordinating solvents afforded metal compounds, which were isolated in the solid state and characterized. The 1:4 molar reactions of 1 with methyl formate (HCO₂Me), methyl methoxyacetate (MeOCH₂CO ₂Me) and methyl D,L-lactate [D,L-HOCH(Me)CO₂Me] gave the dinuclear complex [MoOCl₃{O=C(H)OMe}]₂ (2) and the mononuclear complexes MoOCl₃[κ²-O=C(OMe)CH ₂OMe] (6a) and MoOCl₃[κ²-O=C(OMe)CH(Me) OH] (6b), respectively. According to NMR/GC-MS analyses, activation of the ester moiety in part of the organic material took place in distinct cases. The molybdenum(IV) 1D coordination polymers [MoCl₄-κ²- {trans-(CO₂R)CH=CH(CO₂R)}]_n (R = Me, 3a; R = Et, 3b) were prepared by treatment of 1 with 2 equiv. of alkyl fumarates. In contrast, the mononuclear Mo^IV complexes MoCl₄[κ ²-CH₂(CO₂Me)₂] (4) and MoCl ₄[κ²-{cis-(CO₂Me)CH=CH(CO ₂Me)}] (5) were obtained from 1/CH₂(CO₂Me) ₂ and 1/cis-maleate, respectively. The molecular structures of 2, 3a, 3b, 4, 6a and 6b were ascertained by X-ray diffraction studies. Copyright

Full text of DOI:10.1002/ejic.201201217

FULL PAPER
DOI:10.1002/ejic.201201217
The Reactivity of Molybdenum Pentachloride with Ester
Molecules: Ester Activation, Metal Reduction, and
Synthesis of 1D Coordination Polymers
[
a]
[a]
[a]
Sara Dolci, Fabio Marchetti,* Guido Pampaloni, and
Stefano Zacchini[
b]
Keywords: Molybdenum / O ligands / Structure elucidation / Ligand activation / Coordination polymers
The reactions of Mo
2
Cl10 (1) with stoichiometric amounts of
moiety in part of the organic material took place in distinct
a variety of molecules containing the ester functionality in
anhydrous noncoordinating solvents afforded metal com- [MoCl
cases. The molybdenum(IV) 1D coordination polymers
2
4
-κ -{trans-(CO
2
R)CH=CH(CO
2
R)}]
n
(R = Me, 3a; R =
pounds, which were isolated in the solid state and charac-
terized. The 1:4 molar reactions of 1 with methyl formate
Et, 3b) were prepared by treatment of 1 with 2 equiv. of alkyl
IV
fumarates. In contrast, the mononuclear Mo complexes
2
2
(HCO
2
Me), methyl methoxyacetate (MeOCH
2
CO
2
Me) and
MoCl
4
[κ -CH
2
(CO
2
Me)
2
]
(4) and MoCl
4
[κ -{cis-(CO
(CO
2
Me)-
Me)
2
methyl
D,L-lactate [D,L-HOCH(Me)CO
2
Me] gave the dinu-
CH=CH(CO
2
Me)}] (5) were obtained from 1/CH
2
2
clear complex [MoOCl
3
{O=C(H)OMe}]
2
(2) and the mononu-
and 1/cis-maleate, respectively. The molecular structures of
2, 3a, 3b, 4, 6a and 6b were ascertained by X-ray diffraction
studies.
2
clear complexes MoOCl
3
[κ -O=C(OMe)CH
2
OMe] (6a) and
2
MoOCl
3
[κ -O=C(OMe)CH(Me)OH] (6b), respectively. Ac-
cording to NMR/GC–MS analyses, activation of the ester
Introduction
list of crystallographically characterized metal derivatives
resulting from the interaction of Mo Cl with one single
2
10
Recently, we have carried out a systematic investigation
of the reactivity of niobium and tantalum pentahalides
[
7–9]
organic reactant is limited to only a few cases.
During our preliminary studies on the reactivity of
Mo Cl with O-containing molecules, we observed compli-
MX (M = Nb, Ta; X = F, Cl, Br) with stoichiometric,
5
limited amounts of oxygen species.[ The investigation evi-
1]
2
10
cated patterns in the stoichiometric reactions with acetals
and ketals, which included the interesting formation of new
denced previously unknown aspects of the chemistry of
[
2]
MX5 and contributed to the comprehension of the behav-
[7]
C–C bonds.
[1]
iour of MX in relevant catalytic processes.
5
Later, we communicated on the reactivity of 1 with the
simple amides N,N-dimethylformamide and acetanilide.[
This paper focuses on the room-temperature reactions of
In view of such results, we have moved our attention to
molybdenum pentachloride (1), which is an oxophilic halide
isostructural with niobium pentachloride.[3] Mo Cl is a
commercial, inexpensive chemical that exhibits interesting
performances in metal-directed organic reactions involving
10]
2
10
1
with a variety of molecules with one or two carboxylic
ester functions in noncoordinating solvents (dichlorometh-
ane or chloroform) under strictly anhydrous conditions.
The main metal products of the distinct reactions have been
isolated in the solid state and characterized by analytical
and spectroscopic techniques and, in a number of cases, by
X-ray diffraction. In addition, NMR and GC–MS analyses
have been performed to elucidate the nature of the com-
pounds derived from the eventual activation of the organic
material and, thus, to outline the reaction pathways.
The results obtained will be discussed and compared to
those previously reported for the parallel chemistry of
Nb Cl .
[
4]
oxygen species; in contrast with the employment of 1 in
catalysis, its coordination chemistry has been scarcely ex-
[
5]
plored heretofore. A possible discouraging drawback may
reside in the high moisture sensitivity of 1, which demands
rigorously anhydrous reaction systems, and the variety of
reaction pathways that may take place when 1 is allowed to
contact with potential ligands.[ It is remarkable that the
6,7]
[
a] Dipartimento di Chimica e Chimica Industriale, Università di
Pisa,
Via Risorgimento 35, 56126 Pisa, Italy
E-mail: fabmar@dcci.unipi.it
2
10
Homepage: http://www.dcci.unipi.it/~fabmar/
b] Dipartimento di Chimica Industriale “Toso Montanari”,
Università di Bologna,
[
Results and Discussion
Viale Risorgimento 4, 40136 Bologna, Italy
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201201217.
The 1:4 molar reaction of Mo Cl with methyl formate
2
10
in CH Cl2 afforded the green crystalline complex
2
Eur. J. Inorg. Chem. 2013, 1371–1380
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2 2
Scheme 1. The reaction of Mo Cl10 with HCO Me.
[
MoOCl {O=C(H)OMe}] (2) in 75% yield after workup Table 1. Selected bond lengths [Å] and angles [°] for 2.[a]
3 2
(
Scheme 1). The same compound was previously obtained
Mo(1)–O(1)
Mo(1)–Cl(2)
1.6513(17) Mo(1)–O(2)
2.7799(7) Mo(1)–Cl(2_1)
2.3192(7) Cl(3)–Mo(1)
2.1102(17)
2.4110(6)
2.3082(6)
1.286(3)
[
7]
in low yield by reaction of Mo Cl with CH (OMe) .
2
10
2
2
According to an NMR experiment in CD Cl , ca. Cl(1)–Mo(1)
2
2
C(1)–O(2)
C(2)–O(3)
Cl(2)–Mo(1)–Cl(2_1) 78.27(2)
1.238(3)
1.464(3)
C(1)–O(3)
1
equiv. of ester per metal atom was recovered after hydrol-
ysis of the 1/HCO Me (1:4) reaction mixture (see Exp.
Sect.).
may take place in two steps: (i) Cl–O exchange between O(2)–Mo(1)–Cl(3)
Mo Cl and 2 equiv. of HCO Me to give MoOCl ; (ii) co-
2
Mo(1)–Cl(2)–Mo(1_1) 101.73(2)
[
11]
This evidence suggests that the formation of 2
Cl(1)–Mo(1)–Cl(2_1) 159.65(2) O(1)–Mo(1)–Cl(2)
174.27(6)
133.83(16)
118.62
164.06(5) C(1)–O(2)–Mo(1)
123.7(2) C(1)–O(3)–C(2)
O(2)–C(1)–O(3)
2
10
2
3
ordination of further HCO Me to afford the final product [a] Symmetry operation used to generate equivalent atoms: 1: –x +
2
2
1
7
. In accord with this hypothesis, the 1:2 molar reaction of 2, –y + 1, –z + 2.
with HCO Me resulted in the formation of MoOCl in
2
12]
3
[
0% yield;
the latter was identified by IR spectroscopy
Only half of compound 2 is present within the asymmet-
ric unit, and the rest of the molecule is generated by an
inversion centre. The Mo centres display distorted octahe-
dral geometry and are coordinated by four chlorido ligands
two of which are in bridging positions), one oxido ligand
and one methyl formate ligand. The separation between the
molybdenum centres [4.011(2) Å] is far longer than the sum
of their covalent radii [2.94 Å],
and elemental analysis. Among the possible organic prod-
ucts of the ester activation step [step (i), above], MeCl was
clearly detected by NMR spectroscopy in the expected
amount. The capability of Mo Cl to provide activation of
V
2
10
(
HCO Me contrasts with the behaviour of Nb Cl , which
2
2
10
reacts with methyl formate under similar conditions to give
the thermally robust adduct NbCl [O=C(H)OMe]
Scheme 5).
Compound 2 is a rare example of a crystallographically
characterized dinuclear Mo OCl derivative. The molecular
structure is shown in Figure 1, and the relevant bond
lengths and angles are listed in Table 1.
5
[14]
which clearly indicates
[
13]
(
that there is no bonding between them. The Mo (μ-Cl)2
core of the dimer is planar; two terminal Cl ligands and the
oxido ligands occupy equatorial positions, whereas the
2
V
3
other Cl and HCO Me ligands occupy axial positions. This
2
spatial arrangement differs from that found in the dinuclear
V
Mo complex [MoOCl {O=C(H)OCH CH Cl}] , which
3
7]
2
2
2
[
has axial oxido ligands.
Similar to those in [MoOCl {O=C(H)OCH CH Cl}] ,
3
2
2
2
the two oxygen ligands bonded to different molybdenum
centres in 2 are in relative trans positions. The Mo(1)–O(1)
distance [1.6513(17) Å] is considerably shorter than the
Mo(1)–O(2) distance [2.1102(17) Å], in view of the double-
bond character of the former and the coordinative nature
of the latter. Moreover, the very short Mo(1)–O(1) distance
falls in the usual range previously found for other com-
[
7,9,10,15]
pounds containing an Mo=O double bond.
The
bonding parameters of the HCO Me ligands are as ex-
2
pected, and both the C(1)–O(2) [1.238(3) Å] and the C(1)–
O(3) [1.286(3) Å] interactions display considerable π char-
acter.
The characteristic IR features of 2 are the absorptions at
–1
1
615 and 998 cm , which are attributed to the carbonyl
Figure 1. Molecular structure of 2 with key atoms labelled. Sym-
metry operation used to generate equivalent atoms: –x + 2, –y +
(
the corresponding band in uncoordinated methyl formate
–1 [16]
1, –z + 2. Thermal ellipsoids are at the 50% probability level.
is at 1729 cm ) and Mo=O stretching vibrations, respec-
Eur. J. Inorg. Chem. 2013, 1371–1380
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2
Scheme 2. Synthesis of 1D coordination polymers and mononuclear derivatives by reactions of Mo Cl10 with diesters.
tively. Magnetic susceptibility analysis of 2 was performed CH=CH(CO R) (R = Me, Et) ligands completely preserve
2
at room temperature, and the result is in accord with those their nature after coordination with regard to both geome-
V
of previous mononuclear oxido–Mo
complexes try and bonding parameters.
[
9,12,17]
(Table S1).
In other words, no significant magnetic
exchange is observed between the two Mo centres in 2, in
2
–
analogy with the dinuclear [Mo O Cl (μ-Cl) ] ion. The
2
2
6
2
structure of the latter resembles that of 2, but has two
chlorido ligands in place of the ester ligands.[
18]
To consider the possible role played by bifunctional
linker molecules in the construction of coordination poly-
[
19]
mers, the present study was extended to compounds con-
taining two ester moieties spaced by one (dimethyl malon-
ate) or two carbon atoms (dimethyl maleate, diethyl fumar-
ate).
Thus, the 1:2 molar reactions of 1 with trans-(CO R)-
2
CH=CH(CO R) (R = Me, Et) afforded the 1D coordina-
2
2
tion polymers [MoCl -κ -{trans-(CO R)CH=CH(CO R)}]
4
2
2
n
(
R = Me, 3a; R = Et, 3b; Scheme 2).
The IR spectra (solid state) of 3a and 3b displayed the
absorptions ascribable to the alkene moiety (at ca.
–
1
1
1
650 cm ) and the coordinated carbonyl groups (e.g., at
–
1
607 cm for 3b).
Magnetic susceptibility analyses for 3a and 3b (see Exp.
Sect. and Table S1) gave values substantially lower than
IV
[5a,20]
those generally found for Mo Cl adducts,
which sug-
4
gests the occurrence of magnetic interactions between the
molybdenum centres. The interaction is probably made pos-
sible by the unsaturated bridging diester ligands along the
1
chains. The H NMR spectra of 3a and 3b are supplied as
Supporting Information (Figures S2 and S3).
ORTEP representations of the molecular structures of 3a
and 3b are shown in Figures 2 and 3, and relevant bond
lengths and angles are listed in Tables 2 and 3. Both species
2 2
Figure 2. Molecular structure of 3a·CH Cl . (a) ORTEP depiction
of the asymmetric unit with key atoms labelled. Thermal ellipsoids
are at the 50% probability level. (b) Representation of a fragment
of the polymeric chain.
2
consist of infinite [MoCl -κ -{trans-(CO R)CH=CH-
4
2
(
CO R)}] (R = Me, 3a; R = Et, 3b) monodimensional
2 n
chains. Views of the monodimensional chain of 3b are given
IV
in the Supporting Information (Figure S1). Each Mo cen-
To see if some activation of the organic reactant could
tre is coordinated to four terminal Cl ligands and two carb- be forced by high-temperature conditions, we heated an
onyl atoms of two different trans-(CO R)- Mo Cl /trans-(CO Et)CH=CH(CO Et) mixture in CDCl
CH=CH(CO R) (R = Me, Et) molecules, which results in in a sealed tube at 90 °C for 3 h. Hence, trans-(CO Et)-
O
2
2
10
2
2
3
2
2
a distorted octahedral geometry with the O atoms in rela- CH=CH(CO Et) and EtCl could be recognized in a 10:2
2
tive cis positions. For 3a, an entire molecule is present ratio by NMR spectroscopy after hydrolysis. This point evi-
within the asymmetric unit, whereas only half of 3b is pres- dences that C–O single bond activation could be operative
ent on a mirror plane [that passes through Cl(3), Mo(1) and at high temperature; we did not observe an increase in the
Cl(2)] that generates the whole molecule. The trans-(CO R)- relative amount of EtCl upon increasing the heating time.
2
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Table 3. Selected bond lengths [Å] and angles [°] for 3b.[a]
Mo(1)–O(1)
Mo(1)–Cl(3)
C(1)–O(1)
C(1)–C(2)
O(2)–C(3)
2.154(3)
2.3200(15) Mo(1)–Cl(4)
1.229(5)
1.475(5)
1.470(5)
Mo(1)–Cl(2)
2.3283(15)
2.2587(12)
1.305(5)
1.306(8)
1.505(6)
122.1(3)
114.6(3)
C(1)–O(2)
C(2)–C(2_1)
C(3)–C(4)
O(1)–Mo(1)–O(1_2) 80.84(14) O(1)–C(1)–O(2)
O(1)–C(1)–C(2)
C(1)–C(2)–C(2_1)
C(1)–O(2)–C(3)
123.3(4)
123.0(5)
117.0(3)
O(2)–C(1)–C(2)
C(1)–O(1)–Mo(1) 140.8(3)
O(2)–C(3)–C(4) 110.1(3)
[
1
a] Symmetry operation used to generate equivalent atoms: 1: –x +
, –y, –z + 1; 2: x, y, –z + 1/2.
of the different spatial requirements of the respective diester
ligands. This feature resembles a trend previously reported
for TiCl derivatives. More specifically, ortho- and meta-di-
4
ester-substituted benzenes add to TiCl to give mononu-
4
[
9,21,23]
clear
tive manner.
produce complexes that exist as infinite 1D chains in the
and dinuclear complexes, respectively, in a selec-
[
22]
The reactions of TiCl with para-diesters
4
[
23]
solid state.
The identity of 4 was conclusively established by X-ray
diffraction (Figure 4, relevant bond lengths and angles are
listed in Table 4). The asymmetric unit of 4 contains only
Mo(1), Cl(1), Cl(2), Cl(3) and half of the CH (CO Me)
2
2
2
ligand; the whole molecule is generated by a mirror plane
passing through Mo(1), Cl(2), Cl(3) and C(3). The Mo cen-
tre has a distorted octahedral geometry involving four ter-
minal Cl ligands and a chelating cis-CH (CO Me) ligand.
Figure 3. Molecular structure of 3b. (a) ORTEP depiction of the
2
2
2
asymmetric unit with key atoms labelled. Thermal ellipsoids are at A similar geometry was previously found in other
[20,24]
the 50% probability level. (b) Representation of a fragment of the
polymeric chain.
MoCl (L–L) complexes containing bidentate ligands.
4
Table 2. Selected bond lengths [Å] and angles [°] for 3a.[a]
Mo(1)–O(1)
Mo(1)–Cl(2)
Mo(1)–Cl(4)
C(1)–O(1)
C(1)–C(2)
C(3)–C(4)
C(4)–O(3_1)
O(4)–C(6)
O(1)–Mo(1)–O(3)
O(1)–C(1)–C(2)
C(1)–C(2)–C(3)
C(3)–C(4)–O(4)
O(4)–C(4)–O(3_1)
2.160(6)
2.320(3)
2.295(2)
1.237(9)
1.469(11)
1.487(11)
1.251(9)
1.447(10)
81.2(2)
122.4(8)
121.6(8)
114.9(7)
120.2(8)
Mo(1)–O(3)
Mo(1)–Cl(3)
Mo(1)–Cl(5)
C(1)–O(2)
C(2)–C(3)
O(2)–C(5)
C(4)–O(4)
2.171(6)
2.317(3)
2.250(3)
1.302(10)
1.322(10)
1.472(9)
1.305(9)
O(1)–C(1)–O(2)
O(2)–C(1)–C(2)
C(2)–C(3)–C(4)
C(3)–C(4)_O(3_1)
122.2(8)
115.3(8)
120.6(8)
124.8(8)
Figure 4. Molecular structure of 4 with key atoms labelled. Sym-
metry operation used to generate equivalent atoms: x, –y + 1/2, z.
Thermal ellipsoids are at the 50% probability level.
[a] Symmetry operation used to generate equivalent atoms: 1: x –
1/2, –y + 1/2, z + 1/2.
Table 4. Selected bond lengths [Å] and angles [°] for 4.[a]
The addition of 2 equiv. of CH (CO Me) (dimethyl
2
2
2
Mo(1)–O(1)
Mo(1)–Cl(2)
2.173(4)
2.386(2)
1.226(7)
1.302(7)
Mo(1)–Cl(1)
Mo(1)–Cl(3)
C(2)–C(3)
2.195(2)
2.351(2)
1.505(8)
1.462(8)
malonate) to a dichloromethane suspension of 1 resulted in
2
the formation of the mononuclear species MoCl [κ - O(1)–C(2)
4
C(2)–O(2)
Cl(2)–Mo(1)–Cl(3)
O(1)–Mo(1)–Cl(1_1) 166.64(13) O(1)–Mo(1)–O(1_1)
Mo(1)–O(1)–C(2)
O(1)–C(2)–C(3)
O(2)–C(1)
CH (CO Me) ] (4) in ca. 80% yield (Scheme 2). The analo-
2
2
2
168.56(8) Cl(1)–Mo(1)–O(1_1) 166.64(13)
gous reaction of Mo Cl with dimethyl maleate [cis-
2
10
76.9(2)
(
CO Me)CH=CH(CO Me)] gave the mononuclear complex
2 2
131.5(4)
125.3(6)
111.7(7)
O(1)–C(2)–O(2)
O(2)–C(2)–C(3)
C(2)–O(2)–C(1)
121.8(6)
112.9(5)
117.1(5)
2
MoCl [κ -{cis-(CO Me)CH=CH(CO Me)}] (5, Scheme 2).
4
2
2
The use of excess diester did not affect the outcome. The C(2)–C(3)–C(2_1)
different structure of 4 and 5 (mononuclear) with respect to
that of 3a and 3b (polynuclear) seems to be a consequence –y + 1/2, z.
[a] Symmetry operation used to generate equivalent atoms: 1: x,
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The Mo(1)–Cl(1) interactions [2.195(2) Å] trans to the O-
donor organic ligand are shorter than the Mo(1)–Cl(2)
2.386(2) Å] and Mo(1)–Cl(3) interactions [2.351(2) Å],
which are in mutual trans positions, owing to the different
[
[
9,25]
trans effects of the ligands.
C(2) displays an almost pure
2
sp hybridization [sum of angles 360.0(10)°], and both the
C(2)–O(1) [1.226(7) Å] and C(2)–O(2) bonds [1.302(7) Å]
Scheme 3. The 1:4 molar reactions of Mo
oxyacetate and methyl d,l-lactate.
2
Cl10 with methyl meth-
show considerable
1.505(8) Å] is a pure C(sp )–C(sp ) single bond.
The IR spectrum of the solid obtained from the 1:2 reac-
tion of 1 with CH (CO Me) is coherent with the single- susceptibilities are in accordance with the data available for
π
character, whereas C(2)–C(3)
2
3
[
2
2
2
V
[9,12,17]
crystal analysis of 4 (vide infra). In particular, the bands of Mo (O)Cl
the carboxylato groups were found at 1684, 1658, 1619 and
The molecular structures of 6a and 6b were ascertained
605 cm . The characterization of 4 was completed by by X-ray diffraction (Figures 4 and 5; relevant bond lengths
NMR spectroscopy, conductivity and magnetic analyses and angles are listed in Table 5). In both molecules, the
-based complexes.
3
–
1
1
V
(
see Exp. Sect. and Table S1).
Compound 5 was unambiguously characterized by Mo atom is moved towards the oxido ligand, as is usually
means of elemental analysis, IR spectroscopy and magnetic found in Mo(O)Cl (L) complexes with monodentate or bi-
Mo centres display distorted octahedral geometry as the
3
2
[
9,15,26–28]
susceptibility. The IR spectrum exhibited the characteristic dentate ligands.
The coordination around the
absorptions of the coordinated carbonyl groups at metal centre is completed by three Cl atoms in a meridional
–
1
1
668 cm (the corresponding band in uncoordinated di- arrangement and two O atoms of the chelating ROCH(RЈ)-
–
1 [16]
methyl maleate falls at 1732 cm ). The magnetic analysis CO Me ligand. After coordination, the organic ligand
indicated the presence of Mo centres, in agreement with forms a five-membered ring, in which one carbonyl O(2)
the results obtained for the mononuclear Mo complex 4 donor is trans to Cl(2). O(4), trans to the oxido ligand, is
and other analogous MoCl L complexes.
2
IV
IV
[20]
an ether function in 6a and an alcohol group in 6b. In view
4
2
The formation of complexes 3–5 is the consequence of of the different trans environments, the Mo(1)–O(2) dis-
monoelectron reduction of the metal centre; the metal re- tances [2.1444(17) and 2.1159(15) Å for 6a and 6b, respec-
duction is likely to proceed by elimination of elemental tively] are sensibly shorter than the Mo(1)–O(4) distances
chlorine. Indeed, the treatment of the Mo Cl / [2.3136 (17) and 2.3138(16) Å]. Moreover, the Mo(1)–O(2)
2
10
CH (CO Me) reaction mixture in CD Cl with cyclo- distances are considerably longer than the Mo(1)–O(1) dis-
2
2
2
2
2
pentene allowed us to detect cis-1,2-dichlorocyclopentane tances [1.6532(17) and 1.6545(16) Å], as expected in con-
by NMR spectroscopy (see Exp. Sect.). It has to be re- sideration of the double-bond character of the latter.
marked that an analogous experiment on the Mo Cl /
2
10
HCO Me mixture (vide infra) did not allow us to observe
2
products of Cl addition to cyclopentene.
Studies on the reactivity of Mo Cl10 with ortho-diester-
2
substituted benzenes were formerly reported by Sobota and
co-workers: interestingly, the 1:4 molar reaction of 1 with
1
,2-C H (CO Et) resulted in oxygen transfer from half of
6 4 2 2
the organic reactant to the metal centre and the consequent
V
formation of the Mo
complex MoOCl [1,2-C H -
3 6 4
[
9]
(
CO Et) ], which contains a bidentate diester ligand. It
2
2
can be concluded that the nature of the linkage between the
two ester units is crucial to the outcome of the interaction
of the diester molecule with 1 (i.e., monoelectron reduc-
tion of the metal centre or activation of the organic reac-
tant).
Figure 5. Molecular structure of 6a with key atoms labelled. Ther-
mal ellipsoids are at the 50% probability level.
2
The study of the reactivity of 1 with esters was extended
The molecules of 6b exist as {MoOCl [κ -O=C(OMe)-
3
to two species containing two different oxygen functionali- CH(Me)OH]}2 dimers within the unit cell owing to the
ties, that is, MeOCH CO Me (methyl methoxyacetate) and presence of two hydrogen bonds involving O(4), H(4) and
2
2
d,l-HOCH(Me)CO Me (methyl lactate). The mononuclear Cl(3) atoms of both molecules [O(4)–H(4) 0.847(17) Å;
2
2
complexes MoOCl [κ -O=C(OMe)CH OMe] (6a) and H(4)···Cl(3_1) 2.266(18) Å; O(4)···Cl(3_1) 3.1091(17) Å;
3
2
2
MoOCl [κ -O=C(OMe)CH(Me)OH] (6b) were the only O(4)–H(4)···Cl(3_1) 174(3)°; symmetry transformations
3
products that could be isolated from the reactions used to generate the equivalent atom Cl(3_1): 1: –x + 2, –y
(Scheme 3).
+ 1, –z + 1; Figure 6].
The IR spectra (in the solid state) of 6a and 6b show
To establish the origin of the oxido moieties in com-
typical bands accounting for the carbonyl and the Mo=O pounds 6a and 6b, we allowed 1 to react with 4 equiv. of
–
1
moieties at ca. 1620 and 1000 cm , respectively. Magnetic methyl methoxyacetate or methyl d,l-lactate in CD Cl in
2
2
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Table 5. Selected bond lengths [Å] and angles [°] for 6a and 6b.
to more than one pathway (Scheme 4). The transformations
consist of C–O bond cleavage and presumably provide the
oxido unit (Figure 3); moreover, the production of
CH (OMe) and O=C(OMe) should be interpreted as the
6a
6b
Mo(1)–O(1)
Mo(1)–O(2)
Mo(1)–O(4)
Mo(1)–Cl(1)
Mo(1)–Cl(2)
Mo(1)–Cl(3)
C(1)–O(2)
1.6532(17)
2.1444(17)
2.3136(17)
2.3673(7)
2.3166(6)
2.3610(7)
1.244(3)
1.6545(16)
2.1159(15)
2.3138(16)
2.3349(6)
2.3132(6)
2.3965(6)
1.234(3)
2
2
2
result of the coupling of fragments formed by the degrada-
tion processes. This is an interesting point, because high-
oxidation-state transition metal halides are generally cap-
able of C–O bond activation, but do not normally promote
[
29]
coupling between the resulting fragments.
C(1)–O(3)
1.290(3)
1.299(3)
O(3)–C(4)
C(1)–C(2)
1.456(3)
1.494(4)
1.465(3)
1.508(3)
C(2)–O(4)
1.427(3)
1.433(3)
O(1)–Mo(1)–O(4)
Cl(2)–Mo(1)–O(2)
Cl(1)–Mo(1)–Cl(3)
O(2)–Mo(1)–O(4)
Mo(1)–O(2)–C(1)
O(2)–C(1)–C(2)
O(2)–C(1)–O(3)
O(3)–C(1)–C(2)
C(1)–C(2)–O(4)
C(2)–O(4)–Mo(1)
C(1)–O(3)–C(4)
165.29(7)
161.24(5)
161.97(2)
71.16(6)
120.46(16)
121.9(2)
123.8(2)
114.3(2)
107.10(19)
114.49(14)
118.49(19)
169.75(7)
156.66(5)
163.42(2)
70.40(6)
123.46(15)
122.8(2)
123.0(2)
114.2(2)
104.45(18)
118.81(13)
117.95(18)
2
Scheme 4. Reactivity of Mo Cl10 with methyl methoxyacetate and
methyl d,l-lactate: organic products detected by NMR/GC–MS af-
ter hydrolysis of the 1:4 reaction mixtures.
NMR analysis of the Mo Cl /lactate mixture revealed
2
10
the presence of HOCH(Me)CO Me, MeCl and HOCH-
2
(
Me)CO H in nearly equimolar quantities. This indicates
2
that, once again, part of the organic reactant is likely to be
involved in the formation of the oxido ligand by activation
of C–O bonds to give the coordination compound 6b
(Scheme 4).
Conclusions
In the framework of our research on the reactivity of
early transition metal halides, we have described the interac-
tion of molybdenum(V) pentachloride with a selection of
ester-containing molecules.
Molybdenum pentachloride may activate the ester unit
at room temperature by chlorine transfer. Nevertheless, the
reactions with diesters with two units spaced by [CH ] or
2
[CH=CH] lead to monoelectron reduction of the metal
atom and, thus, formation of mono- or polynuclear
molybdenum(IV) tetrachloride adducts. The redox process
is probably accompanied by Cl production.
2
A comparative overview of the reactivity of Mo Cl and
2
10
Nb Cl with ester compounds is shown in Scheme 5. The
2
10
higher tendency of the former to give Cl elimination reac-
tions reflects the lower stability of the Mo–Cl bond in
–1
MoCl5(g) (81.8 kcalmol ) compared to the Nb–Cl bond in
–1 [30]
NbCl5(g) (97.5 kcalmol ).
Otherwise, the different reaction behaviour (i.e., ester ac-
b) Representation of the H-bonded dimers present in the unit cell tivation or metal reduction) of Mo Cl with different or-
Figure 6. (a) Molecular structure of 6b with key atoms labelled.
(
2
10
of 6b. Thermal ellipsoids are at the 50% probability level.
ganic compounds appears difficult to fully rationalize.
Probably, both the properties of the organic reactant (in-
sealed NMR tubes. After 2 d, the mixtures were treated cluding its mono- or bicoordination ability) and the high
[
11]
with water.
tendency of the molybdenum centre to achieve the stable
NMR/GC–MS analysis of the mixture derived from the hexacoordination interweave to determine the reaction out-
Mo Cl /methyl methoxyacetate system showed the pres- come.
2
10
ence of MeOCH CO Me, MeCl and minor amounts of
The results presented herein expand the knowledge on
2
2
CH (OMe) and O=C(OMe) . This indicates that part of the coordination chemistry of Mo Cl and may give a con-
2
2
2
2
10
the organic substrate, which is not found as a ligand in the tribution to the development of Mo Cl -mediated organic
2
10
final compound 6a, undergoes transformations according reactions.
Eur. J. Inorg. Chem. 2013, 1371–1380
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2 2
Scheme 5. Comparative overview of the chemistry of Mo Cl10 and Nb Cl10 with ester compounds.
tions were introduced according to König.[31] NMR spectra were
recorded at 293 K with a Bruker Avance DRX400 instrument
equipped with a BBFO broadband probe. The chemical shifts for
Experimental Section
General Considerations: Warning: All the metal products reported
in this paper are highly moisture-sensitive, thus rigorously anhy-
drous conditions were required for the reaction and crystallization
procedures. The reaction vessels were oven-dried at 140 °C, evacu-
1
13
H and C were referenced to the nondeuterated aliquot of the
1
13
solvent. The spectra were fully assigned by H– C correlation mea-
sured through gradient-selected heteronuclear single quantum cor-
ated (10–2 Torr) and then filled with argon prior to use. Mo
Cl10
[32]
2
relation (gs-HSQC) and gs-HMBC experiments. GC–MS analy-
was purchased from Strem (99.6% purity) and stored in sealed
tubes under argon. Once isolated, the metal products were stored
in sealed glass tubes under argon. All organic reactants were com-
mercial products (Sigma–Aldrich) and were stored under argon as
received. Solvents (Sigma–Aldrich) were distilled before use from
appropriate drying agents. Infrared spectra were recorded at 298 K
with a Perkin–Elmer FTIR spectrometer equipped with a universal
attenuated total reflectance (UATR) sampling accessory. The mag-
netic susceptibilities (reported per Mo atom) of solid samples at
ses were performed with an HP6890 instrument interfaced with an
MSD-HP5973 detector and equipped with a Phenonex Zebron col-
umn. Carbon and hydrogen analyses were performed with a Carlo
Erba 1106 instrument. The Cl content was determined by the Mohr
[33]
method
on solutions obtained by dissolution of the solids in
aqueous KOH at boiling temperature, followed by cooling of the
solution to room temperature and the addition of HNO
tralize the solution.
3
to neu-
2
98 K were measured with a Magway MSB Mk1 magnetic suscep-
[MoOCl
added to Mo
3
{O=C(H)OMe}]
2
(2): Methyl formate (2.90 mmol) was
Cl (10 mL) in a
tibility balance (Sherwood Scientific Ltd.). Diamagnetic correc-
2
Cl10 (0.390 g, 0.72 mmol) in CH
2
2
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Schlenk tube. The mixture was stirred at room temperature for
8 h, during which progressive dissolution of the solid into a green
solution was observed. The final solution was concentrated (to ca.
large excess of water (ca. 5 mmol) was added. The obtained solu-
tion was separated from the precipitate and analyzed by NMR
spectroscopy. trans-(EtO C)CH=CH(CO Et) and EtCl were de-
2 2
1
3
–
0
3
mL) and layered with heptane (20 mL). The tube was stored at
30 °C, and green crystals of 2 were collected after 72 h. Yield:
tected in a 10:2 ratio.
2
MoCl
4
[κ -CH
2
(CO
2
Me)
2
] (4): Mo
2
Cl10 (0.191 g, 0.350 mmol) in
(CO Me) (0.700 mmol).
2 4 3 3
.298 g, 75%. C H Cl MoO (278.35): calcd. C 8.63, H 1.45, Cl
CH Cl
2
2
(15 mL) was treated with CH
2
2
2
8.21; found C 8.38, H 1.39, Cl 37.98. IR (solid state): ν˜ = 3383
The mixture was stirred at room temperature for 18 h. The final
brown solution was filtered into a Schlenk tube to remove solid
material, concentrated (ca. 3 mL) and layered with hexane. Com-
pound 4 was obtained as a semicrystalline ochre-yellow solid upon
storing the tube at –30 °C for 4 d. Yield: 0.212 g, 82%.
[br., ν(OC–H)], 2962 (w), 1659 (m, sh), 1615 [vs, ν(C=O)], 1431
(m), 1372 (m), 1312 (m), 1284 (m), 1175 (w), 1088 (w), 998 [vs, ν
–1
(Mo=O)], 883 (m), 807 (m), 734 (s) cm . Magnetic measurement:
corr
–3
χ
M
= 1.03ϫ10 cgsu, μeff = 1.58 BM.
(0.35 mmol) and methyl formate
0.72 mmol) were added to a suspension of Mo Cl10 (0.18 mmol)
in CD Cl (0.60 mL) in an NMR tube. The tube was sealed, briefly
In a different experiment, CHCl
3
5 8 4 4
C H Cl MoO (369.87): calcd. C 16.24, H 2.18, Cl 38.34; found C
(
2
16.01, H 2.31, Cl 38.10. IR (solid state): ν˜ = 3010 (w), 2960 (w),
2883 (m), 1684 (vs), 1658 (s), 1619 (vs), 1605 [s, sh, ν(C=O)], 1447
(vs), 1388 (s), 1372 (s), 1355 (vs), 1240 (vs), 1196 (s), 1171 (s), 1025
(w), 995 (vs), 954 (m), 930 (m), 889 (s), 803 (w), 781 (w–m), 697
2
2
shaken in order to homogenize the content and stored at room
temperature for 4 d. Water (ca. 5 mmol) was then added into the
tube, and the precipitation of a dark solid from a yellow solution
occurred. The solution was analyzed by 1H NMR spectroscopy,
–
1
corr
–3
(w) cm . Magnetic measurement: χ
M
= 2.34ϫ10 cgsu, μeff
CN): δ = 3.69 (br. s, 3 H, CH ), 3.36 (br.
2 3
) ppm. C{ H} NMR (CD CN): δ = 167.4 (CO), 53.8
=
1
2.37 BM. H NMR (CD
s, 2 H, CH
(CH ), 42.1 (CH ) ppm. Λ = 0.21 Scm mol .
2 M
3
3
1
3
1
which pointed to the presence of CHCl
:1:1 ratio.
3
, HCO
2
Me and MeCl in a
2
–1
1
3
The reaction of methyl formate (0.850 mmol) with 1 (0.42 mmol) An NMR study was conducted on a solution obtained by allowing
in CH Cl (10 mL) in a Schlenk tube afforded a brown mixture Mo Cl10 (0.160 mmol) to react with CH (CO Me) (0.350 mmol)
in CD Cl (0.70 mL). The mixture was kept in a sealed NMR tube
at room temperature for 7 d. The tube was then opened, and H
was added in excess. The resulting mixture was analyzed by NMR
spectroscopy; CH (CO Me) was the only product detected.
2
2
2
2
2
2
after 18 h. Removal of the volatile materials gave a brown solid,
which was washed with hexane (2ϫ 10 mL), dried and then ana-
lyzed by IR spectroscopy and elemental analysis. Yield: 0.130 g,
2
2
2
O
7
0%. Cl
3
MoO (218.30): calcd. Cl 48.72; found Cl 47.78. IR (solid
2
2
2
–1 [12]
state): ν˜ = 1007 [vs, ν(Mo=O)] cm .
In a different experiment, Mo
(0.60 mL) was treated with CH
2
Cl10 (0.150 mmol) in CD
2 2
Cl
2
[MoCl
4
-κ -{trans-(CO
2
R)CH=CH(CO
2
R)}]
n
(R = Me, 3a; R = Et,
2
(CO Me) (0.300 mmol) in an
2
2
3
(
b). General Procedure: The appropriate organic reactant
0.800 mmol) was added to a suspension of Mo Cl10 (0.400 mmol)
in CH Cl (10 mL). The mixture was stirred at room temperature
NMR tube. The tube was then sealed, shaken to homogenize the
content and stored at room temperature for 40 min. The tube was
then cooled to ca. –80 °C and opened to introduce cyclopentene
(0.150 mmol). The tube was sealed again and then stored at room
2
2
2
for 6 d. The final solution was filtered into a Schlenk tube to re-
move solid material, concentrated (ca. 3 mL) and layered with hex-
ane. A crystalline solid was collected after storage of the tube at
temperature for 18 h. Subsequent NMR analysis revealed the pres-
1
ence of cis-1,2-dichlorocyclopentane. H NMR (CD
2
Cl
2
): δ = 4.46,
1
3
1
–
30 °C for 4 d. For 3b, crystals suitable for X-ray analysis were
2.00, 1.79 (m) ppm. C NMR{ H} (CD
23.0 ppm.
2 2
Cl ): δ = 63.0, 37.1,
obtained from a concentrated CDCl solution stored at –30 °C for
3
1
week.
2
MoCl
Mo
(0.800 mmol) in CH
4
[κ -{cis-(CO
2
Me)CH=CH(CO
2
Me)}] (5):
Me)CH=CH(CO
2
(15 mL) was stirred at room temperature
A
mixture of
3a: Red, 0.226 g, 74% yield. C
6
H
8
Cl
4
MoO
4
(381.88): calcd. C
2
Cl10 (0.219 g, 0.400 mmol) and cis-(CO
Cl
2
2
Me)
18.87, H 2.11, Cl 37.14; found C 18.62, H 2.23, Cl 37.04. IR (solid
2
state): ν˜ = 3019 (w), 2955 (w), 1651 [m, sh, ν(C=C)], 1633 (s), 1613 for 2 d. The final red solution was concentrated (ca. 3 mL), layered
(
(
6
4
1
1
s), 1591 [vs, ν(C=O)], 1440 (s), 1370 (w), 1318 (vs), 1245 (m), 1157
m), 1015 (m), 994 (vs), 961 (s), 902 (m), 884 (w), 783 (w), 771 (m), after 3 d. Yield: 0.235 g, 77%. C
with pentane and stored at –30 °C. A red powder was collected
Cl MoO (381.88): calcd. C
6
H
8
4
4
–
1
corr
70 (w–m) cm . Magnetic measurements:
χ
M
=
18.87, H 2.11, Cl 37.14; found C 19.12, H 1.96, Cl 36.70. IR (solid
state): ν˜ = 3058 (w), 2988 (w), 2941 (w), 1668 (s), 1644 [m, ν(C=C)],
1610 [vs, ν(C=O)], 1468 (m), 1428 (vs), 1386 (w–m), 1377 (w–m),
1317 (m), 1300 (m), 1245 (vs), 1214 (s), 1095 (m), 1009 (w), 989
.78ϫ10–4 cgsu, μeff = 1.07 BM. H NMR (CD
H, CH), 3.05 (s, 3 H, CH
66.8 (CO), 142.0 (CH) ppm; CH
1
Cl
2
): δ = 7.16 (s,
Cl ): δ =
2
) ppm. 13C{ H} NMR (CD
1
3
2
2
3
signal not observed.
–
1
corr
(
=
vs), 930 (w), 831 (m), 814 (s) cm . Magnetic measurement: χ
M
3
b: Orange-brown, 0.246 g, 75% yield. C MoO (409.93):
8
H12Cl
4
4
–
3
2.49ϫ10 cgsu, μeff = 2.45 BM.
calcd. C 23.44, H 2.95, Cl 34.59; found C 23.21, H 2.63, Cl 34.11.
IR (solid state): ν˜ = 2990 (w), 2901 (vw), 1651 [m–s, ν(C=C)], 1607 NMR analysis was conducted on a solution obtained by allowing
vs, ν(C=O)], 1464 (m), 1409 (m), 1317 (m–s), 1297 (vs), 1241 (m), Mo Cl10 (0.150 mmol) to react with cis-(CO Me)CH=CH(CO Me)
096 (w), 1023 (m–s), 994 (m–s), 974 (m), 962 (w–m), 866 (m), 766 (0.300 mmol) in CD Cl (0.70 mL). The mixture was kept in a se-
aled NMR tube at room temperature for 7 d. The tube was then
opened, and H O was added in excess. The resulting mixture was
NMR spectroscopy, and cis-(CO Me)-
Me) was the only product detected.
[
2
2
2
1
2
2
–1
corr
(
3
1
m–w), 667 (w) cm . Magnetic measurement:
χ
M
=
.87ϫ10–4 cgsu, μeff = 0.96 BM. H NMR (CD
H, CH), 3.64 (m, 2 H, CH ), 1.90 (m, 3 H, CH
Cl ): δ = 165.0 (CO); 140.2 (CH), 40.9 (CH
1
Cl
) ppm. C{ H}
): δ = 7.17 (s,
2
2
2
1
3
1
2
3
analyzed
by
2
NMR (CD
CH ) ppm.
2
2
2
), 19.2 CH=CH(CO
2
(
3
2
MoOCl
3
[κ2-
MoOCl
3
[κ -O=C(OMe)CH
2
OMe] (6a) and
In another experiment, Mo
2
Cl10 (0.226 mmol), CDCl
3
(0.70 mL)
O=C(OMe)CH(Me)OH] (6b): In a Schlenk tube, CH
2
Cl
2
(10 mL)
and trans-(EtO C)CH=CH(CO
2
2
Et) (0.452 mmol) were introduced and MeOCH
2
CO Me (3.00 mmol) were added to Mo
2
2
Cl10 (1,
into an NMR tube. The tube was sealed, shaken and maintained
at room temperature for 14 d. The resulting orange-brown mixture
was heated at ca. 90 °C for 3 h; the tube was then opened, and a
0.410 g, 0.750 mmol). The mixture was stirred for 6 h. The resulting
green solution was concentrated (to ca. 3 mL) and layered with
hexane. The tube was stored at –30 °C for 7 d. Compound 6a was
Eur. J. Inorg. Chem. 2013, 1371–1380
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collected as
Cl MoO
a
green crystalline solid. Yield: 0.261 g, 54%.
O=C(OMe)CH(Me)OH] (6b) are reported in Table 6. The diffrac-
tion experiments were carried out with a Bruker APEX II dif-
C
4
H
8
3
4
(322.40): calcd. C 14.90, H 2.50, Cl 32.99; found C
1
1
4.45, H 2.62, Cl 32.39. IR (solid state): ν˜ = 2981 (m), 2889 (w),
623 [vs, ν(C=O)], 1482 (m), 1442 (w), 1409 (m), 1396 (vs), 1316
fractometer equipped with a CCD detector by using Mo-K
α
radia-
tion. Data were corrected for Lorentz polarization and absorption
[
34]
(m–s), 1238 (w), 1203 (w), 1084 (vs), 1000 [vs, ν(Mo=O)], 940 (s), effects (empirical absorption correction with SADABS).
Struc-
–1
corr
8
1
93 (s), 726 (w) cm . Magnetic measurement:
χ
M
=
tures were solved by direct methods and refined by full-matrix least
–3
2 [35]
.00ϫ10 cgsu, μeff = 1.55 BM.
squares based on all data using F . Hydrogen atoms were fixed
at calculated positions and refined by a riding model, apart from
H(4) in 6b, which was located in the Fourier map and refined iso-
tropically by using a Uiso value 1.2 times that of the parent O atom;
the O–H distance was restrained to 0.89(2) Å. The asymmetric
units of 2, 3b and 4 contain only half of a molecule; the rest is
generated by an inversion centre for 2 and a mirror plane for 3b
Compound 6b was isolated as green crystalline solid from 1
0.328 g, 0.600 mmol) and d,l-HOCH(Me)CO Me (2.40 mmol) by
using a procedure similar to that described for 6a. The reaction
(
2
mixture became a red solution in 1 h and then a green solution
after 4 h. Yield: 0.271 g, 70%. C
4 8 3 4
H Cl MoO (322.40): calcd. C
14.90, H 2.50, Cl 32.99; found C 14.80, H 2.44, Cl 32.53. IR (solid
2 2 2 2
and 4. The CH Cl molecule in 3a·CH Cl is disordered over two
state): ν˜ = 3239 [br., m, ν(O–H)], 2981 (m), 2904 (w), 1625 [vs,
ν(C=O)], 1484 (m), 1441 (w), 1393 (m), 1377 (m), 1343 (w–m), 1308
positions; disordered atomic positions were split and refined iso-
tropically with one occupancy parameter per disordered group.
Similar U restraints (standard uncertainty 0.005) were applied to
(
7
w), 1242 (m), 1110 (s), 995 [vs, ν (Mo=O)], 905 (m), 866 (w–m),
–1
corr
–3
64 (w) cm . Magnetic measurement: χ
M
= 1.10ϫ10 cgsu,
the C atoms of 3a·CH
lecules of 3a·CH Cl were restrained to 1.75(2) Å. CCDC-886702
for 2), -886700 (for 3a·CH Cl ), -886704 (for 3b), -886699 (for 4),
886703 (for 6a) and -886701 (for 6b) contain the supplementary
2 2 2 2
Cl . The C–Cl distances of the CH Cl mo-
μeff = 1.63 BM.
2
2
2 2 2
In another experiment, Mo Cl10 (0.150 mmol), CD Cl (0.60 mL)
(
-
2
2
and MeOCH CO Me (0.600 mmol) were introduced into an NMR
2
2
tube in the order given. The tube was sealed, shaken to homogenize
the content and stored at room temperature for 48 h. The tube was
then opened, and water (ca. 5 mmol) was added in excess to the
green solution. NMR analysis on the resulting light yellow solution
crystallographic data for this paper. These data can be obtained
free of charge from the Cambridge Crystallographic Data Centre
via www.ccdc.cam.ac.uk/conts/data_request/cif.
Supporting Information (see footnote on the first page of this arti-
2 2 2 2
revealed the presence of MeOCH CO Me, MeCl, CH (OMe) and
1
cle): Views of the monodimensional chain of 3b (Figure S1),
H
O=C(OMe) in a ratio of ca. 1:0.7:0.3:0.1.
2
NMR spectra of 3a and 3b (Figures S2 and S3); magnetic data of
, 3a,b, 4, 5 and 6a,b (Table S1).
An analogous experiment was carried out by using d,l-HOCH-
Me)CO Me as reactant. The compounds HOCH(Me)CO Me,
MeCl and HOCH(Me)CO H were recognized in a ratio of ca. 1:1:1
ratio by NMR/GC–MS analysis.
2
(
2
2
2
Acknowledgments
X-ray Crystallographic Study: Crystal data and collection details
2
for [MoOCl
CH=CH(CO
CO Et)CH=CH(CO
MoOCl
3
{O=C(H)OMe}]
Me)}] ·CH Cl
Et)}]
[κ -O=C(OMe)CH
2
(2), [MoCl
(3a·CH Cl ), [MoCl
(3b), MoCl
OMe] (6a)
4
-κ -{trans-(CO
2
Me)-
-κ -{trans-
Me)
3
MoOCl [κ - unconventional species”) for financial support.
The authors wish to thank the Ministero Istruzione, Università e
Ricerca (PRIN 2009 project: “New strategies for the control of
2
2
n
2
2
2
2
4
2
(
2
2
n
4
[κ -CH
and
2
(CO
2
2
] (4), reactions: interactions of molecular fragments with metallic sites in
2
2
3
2
Table 6. Crystal data and experimental details for 2, 3a·CH
3a·CH Cl
MoO
2
Cl
2
, 3b, 4, 6a and 6b.
2
2
2
3b
4
6a
6b
Empirical formula
Formula mass
T [K]
C
4
H
8
Cl
6
Mo
O
2 6
7
C H
10Cl
6
4
8 4
C H12Cl MoO
4
C
5
H
8
Cl
4
MoO
4
C
4
H
8
Cl
3
MoO
4
4 8 3 4
C H Cl MoO
556.68
100(2)
0.71073
466.79
100(2)
0.71073
409.92
100(2)
0.71073
369.85
100(2)
0.71073
322.39
100(2)
0.71073
322.39
100(2)
0.71073
λ [Å]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
monoclinic
P2 /n
monoclinic
P2 /n
orthorhombic
Pbcm
7.8624(14)
11.962(2)
15.797(3)
90
1485.7(5)
4
1.833
monoclinic
P2 /m
orthorhombic
Pbca
7.9070(7)
13.5184(13)
18.9626(18)
90
2026.9(3)
8
2.113
monoclinic
P2 /c
1
1
1
1
9.0008(11)
7.8065(10)
11.0046(14)
99.3500(10)
762.96(17)
2
7.904(2)
16.610(5)
12.665(4)
106.859(4)
1591.2(7)
4
6.0840(17)
13.186(4)
7.766(2)
111.711(3)
578.8(3)
2
7.6518(6)
7.8993(6)
16.9508(12)
97.2470(10)
1016.39(13)
4
β [°]
V [Å ]
3
Z
D
–3
calcd. [gcm ]
2.423
2.704
1.948
1.831
2.122
2.040
2.107
2.052
–1
μ [mm ]
1.600
2.058
F(000)
532
912
808
360
1256
628
Crystal size [mm]
θ limits [°]
Reflections collected
Independent reflections
0.24ϫ0.16ϫ0.12 0.14ϫ0.13ϫ0.11 0.21ϫ0.14ϫ0.12 0.21ϫ0.19ϫ0.13 0.19ϫ0.16ϫ0.13 0.16ϫ0.15ϫ0.12
3.19–25.99
7194
2.08–25.02
12641
2.58–27.00
11363
2.82–27.08
4211
2.15–27.00
15443
2.42–26.00
7552
1490
2788
1685
1328
2207
1995
(
R
int = 0.0207)
(Rint = 0.1572)
2788/59/191
1.014
(Rint = 0.0521)
1685/0/83
1.090
(Rint = 0.0374)
1328/0/70
1.085
(Rint = 0.0386)
2207/0/109
1.084
(Rint = 0.0263)
1995/1/112
1.019
Data/restraints/parameters
1490/0/83
1.293
2
Goodness on fit on F
R
1
[IϾ2σ(I)]
0.0182
0.0578
0.0363
0.0538
0.0250
0.0209
wR (all data)
Largest difference peak/hole [eÅ ]
2
0.0440
0.410/–0.553
0.1275
0.963/–0.656
0.0877
0.900/–0.914
0.1479
2.348/–1.124
0.0643
0.741/–0.531
0.0541
1.025/–0.334
–3
Eur. J. Inorg. Chem. 2013, 1371–1380
1379
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.eurjic.org
FULL PAPER
[
16] Spectral Database for Organic Compounds, SDBS:
http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_
[
[
1] F. Marchetti, G. Pampaloni, Chem. Commun. 2012, 48, 635–
53.
2] a) F. Marchetti, G. Pampaloni, C. Pinzino, S. Zacchini, Angew.
Chem. 2010, 122, 5396; Angew. Chem. Int. Ed. 2010, 49, 5268–
top.cgi.
6
[
[
17] D. B. Soria, M. Barquin, M. J. Gonzalez Garmendia, G. Estiu,
J. Coord. Chem. 2008, 61, 3815–3828.
18] J. Beck, M. Kellner, M. Kreuzinger, Z. Anorg. Allg. Chem.
5
272; b) R. Bini, C. Chiappe, F. Marchetti, G. Pampaloni, S.
2002, 628, 2656–2660.
Zacchini, Inorg. Chem. 2010, 49, 339–351.
[
[
3] J. Beck, F. Wolf, Acta Crystallogr., Sect. B: Struct. Sci. 1997,
[19] S. Kitagawa, R. Kitaura, S. Noro, Angew. Chem. 2004, 116,
2388; Angew. Chem. Int. Ed. 2004, 43, 2334–2375 and refer-
ences therein.
53, 895–903.
4] a) S. R. Waldvogel, S. Trosien, Chem. Commun. 2012, 48, 9109–
9
5
119; b) K. Hackelöer, S. R. Waldvogel, Tetrahedron Lett. 2012,
[20] a) A. V. Butcher, J. Chatt, J. Chem. Soc. A 1970, 2652–2656; b)
E. Hey-Hawkins, H. G. von Schnering, Z. Naturforsch. B 1991,
46, 307–314; c) E. A. Allen, B. J. Brisdon, G. W. A. Fowles, J.
Chem. Soc. A 1964, 4531–4534; d) F. Stoffelbach, D. Saurenz,
R. Poli, Eur. J. Inorg. Chem. 2001, 2699–2703.
ˇ
3, 1579–1581; c) M. Litvic, M. Regovic, K. Smic, M. Lovric,
Bioorg. Med. Chem. Lett. 2012, 22, 3676–3681; d) K. Hackel-
oer, G. Schnakenburg, S. R. Waldvogel, Org. Lett. 2011, 13,
9
16–919; e) N. M. Boshta, M. Bomkamp, G. Schnakenburg,
S. R. Waldvogel, Chem. Eur. J. 2010, 16, 3459–3466; f) A. Kan-
[21] J. Utko, P. Sobota, T. Lis, J. Organomet. Chem. 1987, 334, 341–
azawa, S. Kanaoka, S. Aoshima, Macromolecules 2010, 43,
245.
2739–2747; g) Q. Guo, L. Li, L. Chen, Y. Wang, S. Ren, B.
[22] J. Utko, P. Sobota, T. Lis, J. Organomet. Chem. 1989, 373, 63–
69.
Shen, Energy Fuels 2009, 23, 51–54; h) S. Goswami, A. C. Ma-
ity, Tetrahedron Lett. 2008, 49, 3092–3096; i) Q. Guo, T. Miyaji,
R. Hara, B. Shen, T. Takahashi, Tetrahedron 2002, 58, 7327–
[23] P. Sobota, J. Utko, T. Lis, J. Organomet. Chem. 1990, 393, 349–
358.
7
1
334; j) S. Kumar, M. Manickam, Chem. Commun. 1997, 1615–
[24] C. Stoll, I.-P. Lorenz, H. Nöth, W. Ponikwar, J. Organomet.
Chem. 2000, 602, 24–28.
616.
[
5] a) C. D. Garner, J. M. Charnock, “Molybdenum(III), (IV) and
V)” in Comprehensive Coordination Chemistry (Eds.: G. Wilk-
inson, R. D. Gillard, J. A. McCleverty), Pergamon, Oxford,
987, vol. 3, pp. 1329–1374; b) Z. Dori, “Tungsten” in Compre-
[25] P. Domiano, A. Musatti, M. Nardelli, C. Pelizzi, G. Predieri,
Transition Met. Chem. 1980, 5, 172–175.
[26] B. Fischer, H. Schmalle, E. Dubler, A. Schäfer, M. Viscontini,
Inorg. Chem. 1995, 34, 5726–5734.
(
1
hensive Coordination Chemistry (Eds.: G. Wilkinson, R. D. Gil-
lard, J. A. McCleverty), Pergamon, Oxford, 1987, vol. 3, pp.
[27] U. Scholz, M. Noltemeyer, H. W. Roesky, Z. Naturforsch. B
1988, 43, 937–940.
[28] F. R. Fronczek, R. L. Luck, G. Wang, Inorg. Chim. Acta 2003,
342, 247–254.
973–1022; c) C. G. Young, “Molybdenum” in Comprehensive
Coordination Chemistry II (Eds.: J. A. McCleverty, T. J. Meyer),
Pergamon, Oxford, 2003, vol. 4, pp. 415–527; d) T. Okamura,
N. Ueyama, “Tungsten” in Comprehensive Coordination Chem-
istry II (Eds.: J. A. McCleverty, T. J. Meyer), Pergamon, Ox-
ford, 2003, vol. 4, pp. 529–573.
[29] a) C. A. Bradley, L. F. Veiros, P. J. Chirik, Organometallics
2007, 26, 3191–3200; b) S. Le Caër, M. Heninger, P. Pernot, H.
Mestdagh, J. Phys. Chem. A 2006, 110, 9654–9664; c) C. A.
Bradley, L. F. Veiros, D. Pun, E. Lobkovsky, I. Keresztes, P. J.
Chirik, J. Am. Chem. Soc. 2006, 128, 16600–16612; d) F. Mar-
chetti, G. Pampaloni, Chem. Commun. 2008, 3651–3653; e)
M. C. Cassani, Y. K. Gun’ko, P. B. Hitchcock, A. G. Hulkes,
A. V. Khvostov, M. F. Lappert, A. V. Protchenko, J. Or-
ganomet. Chem. 2002, 647, 71–83; f) I. L. Fedushkin, F. Girgsd-
ies, H. Schumann, M. N. Bochkarev, Eur. J. Inorg. Chem. 2001,
2405–2410; g) M. C. Cassani, M. F. Lappert, F. Laschi, Chem.
Commun. 1997, 1563–1564; h) K. Takaki, M. Maruo, T. Kam-
ata, Y. Makioka, Y. Fujiwara, J. Org. Chem. 1996, 61, 8332–
8334; i) D. J. Duncalf, P. B. Hitchcock, G. A. Lawless, Chem.
Commun. 1996, 269–271; j) B.-J. Deelman, M. Booij, A.
Meetsma, J. H. Teuben, H. Kooijman, A. L. Spek, Organome-
tallics 1995, 14, 2306–2317.
[
6] a) C. Limberg, R. Boese, B. Schiemenz, J. Chem. Soc., Dalton
Trans. 1997, 1633–1637; b) D. L. Kepert, R. Mandyczewsky, J.
Chem. Soc. A 1968, 530–533.
[
[
[
[
[
7] S. Dolci, F. Marchetti, G. Pampaloni, S. Zacchini, Dalton
Trans. 2010, 39, 5367–5376.
8] T. Ernst, A. El-Kholi, U. Müller, K. Dehnicke, Z. Anorg. Allg.
Chem. 1988, 566, 7–17.
9] P. Sobota, S. Szafert, J. Utko, T. Lis, J. Organomet. Chem. 1992,
423, 195–210.
10] S. Dolci, F. Marchetti, G. Pampaloni, S. Zacchini, Inorg. Chem.
011, 50, 3846–3848.
2
11] The hydrolysis of the reaction mixtures facilitates the release
of the organic material from the paramagnetic metal species
and allows the NMR identification of the former. This strategy
has been successfully adopted for the study of the parallel
[30] D. V. Drobot, E. A. Pisarev, Russ. J. Inorg. Chem. 1981, 26, 1–
8.
chemistry of MX
5
(M = Nb, Ta; X = F, Cl, Br); it has been
[31] E. König, “Magnetische Eigenschaften der Koordinations- und
Metallorganischen Verbindungen der Übergangselemente” in
Landolt-Börnstein, Zahlenwerte und Funktionen aus Naturwis-
senschaften und Technik, 6th ed., Springer-Verlag, Berlin,
Göttingen, Heidelberg, 1966, vol. 2, p. 16.
[32] W. Willker, D. Leibfritz, R. Kerssebaum, W. Bermel, Magn.
Reson. Chem. 1993, 31, 287–292.
[33] D. A. Skoog, D. M. West, Fundamentals of Analytical Chemis-
try, 2nd ed., Holt, Rinehart and Winston, Chatham, 1974, p.
233.
proved that H O is inert towards ligand activation reactions,
2
[
1]
see. ref.
[
[
12] M. L. Larson, F. W. Moore, Inorg. Chem. 1966, 5, 801–805.
13] F. Marchetti, G. Pampaloni, S. Zacchini, Dalton Trans. 2009,
6759–6772.
[
14] a) B. Cordero, V. Gómez, A. E. Platero-Prats, M. Revés, J. Ech-
evarría, E. Cremades, F. Barragán, S. Alvarez, Dalton Trans.
2
008, 2832; b) A. Bondi, J. Phys. Chem. 1964, 68, 441.
[
15] a) H. L. Kaufmann, P. J. Carroll, S. J. N. Burgmayer, Inorg.
Chem. 1999, 38, 2600–2606; b) M. A. Bakar, A. Hills, D. L. [34] G. M. Sheldrick, SADABS, University of Göttingen,
Hughes, G. J. Leigh, J. Chem. Soc., Dalton Trans. 1989, 1417–
Göttingen, Germany, 1996.
1
419; c) d) F. A. Cotton, M. Kohli, R. L. Luck, J. V. Silverton,
Inorg. Chem. 1993, 32, 1868–1870; e) C. D. Garner, N. C. How-
[35] G. M. Sheldrick, SHELX97, University of Göttingen,
Göttingen, Germany, 1997.
lader, F. E. Mabbs, A. T. McPhail, J. Chem. Soc., Dalton Trans.
Received: October 8, 2012
1978, 1848–1854.
Published Online: January 8, 2013
Eur. J. Inorg. Chem. 2013, 1371–1380
1380
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim