A crystallographic and spectroscopic study on the reactions of WCl 6 with carbonyl compounds

Article abstract of DOI:10.1039/c2dt32771f

WCl₆, 1, reacted with two equivalents of HC(O)NR₂ (R = Me, Et) in CH₂Cl₂ to afford the W(vi) oxo-derivatives WOCl₄(OCHNR₂) (R = Me, 2a; R = Et, 2b) as main products. The hexachlorotungstate(v) salts [{OC-N(Me)CH₂CH₂CH ₂}₂(μ-H)][WCl₆], 3, and [PhNHC(Me)N(Ph)C(O) Me][WCl₆], 4, were isolated in moderate yields from the 1:2 molar reactions of 1 with N-methyl-2-pyrrolidone (in CH₂Cl₂) and acetanilide (in CDCl₃), respectively. The additions of two equivalents of ketones/aldehydes to 1/CH₂Cl₂ yielded the complexes WOCl₄[OC(R)(R′)] (R = Me, R′ = Ph, 5a; R = R′ = Ph, 5b; R = R′ = Me, 5c; R = R′ = Et, 5d; R = H, R′ = 2-Me-C₆H₄, 5e) and equimolar amounts of C(R)(R′)Cl₂. Analogously, WOCl₃[κ²- {1,2-C₆H₄(O)(CHO)}], 5f, and 1,2-C₆H ₄(OH)(CHCl₂) were obtained from 1 and salicylaldehyde. The 1:1 reaction of 1 with acetone in CH₂Cl₂ resulted in the clean formation of WOCl₄ and 2,2-dichloropropane. Compounds 5a,b,f were isolated as crystalline solids, whereas 5c,d,e could be detected by solution NMR only. The interaction of 1/CH₂Cl₂ with isatin, in a 1:1 molar ratio, revealed to be a new, convenient route for the synthesis of 3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6. The 1:1 reactions of 1 with R′OCH(R)CO₂Me (R = H, R′ = Me; R = Me, R′ = H) in a chlorinated solvent afforded the tungsten(v) adducts WCl ₄[κ²-OCH(R)CO₂Me] (R = H, 7a; R = Me, 7b). 1/CH₂Cl₂ reacted sluggishly with equimolar quantities of trans-(CO₂Et)CHCH(CO₂Et) and CH₂(CO ₂Me)₂ to give, respectively, the W(iv) derivatives WCl₄[κ²-CH₂(CO₂Me) ₂], 8a, and [WCl₄-κ²-{trans-(CO ₂Et)CHCH (CO₂Et)}]_n, 8b, in about 70% yields. The molecular structures of 2a, 3, 4, 5a, 5f, 7a and 7b were ascertained by X-ray diffraction studies.

Full text of DOI:10.1039/c2dt32771f

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An international journal of inorganic chemistry
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Volume 42 | Number 16 | 28 April 2013 | Pages 5589–5944
ISSN 1477-9226
PAPER
Marchetti et al.
A crystallographic and spectroscopic study on the reactions of WCl6 with
carbonyl compounds
1477-9226(2013)42:16;1-N

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PAPER
A crystallographic and spectroscopic study on the
reactions of WCl6 with carbonyl compounds†
Cite this: Dalton Trans., 2013, 42, 5635
Sara Dolci,a Fabio Marchetti,*a Guido Pampalonia and Stefano Zacchinib
WCl6, 1, reacted with two equivalents of HC(O)NR2 (R = Me, Et) in CH2Cl2 to afford the W(VI) oxo-deriva-
tives WOCl4(OCHNR2) (R = Me, 2a; R = Et, 2b) as main products. The hexachlorotungstate(V) salts
[{OvC–N(Me)CH2CH2CH2}2(μ-H)][WCl6], 3, and [PhNHC(Me)N(Ph)C(O)Me][WCl6], 4, were isolated in
moderate yields from the 1 : 2 molar reactions of 1 with N-methyl-2-pyrrolidone (in CH2Cl2) and acetani-
lide (in CDCl3), respectively. The additions of two equivalents of ketones/aldehydes to 1/CH2Cl2 yielded
the complexes WOCl4[OC(R)(R’)] (R = Me, R’ = Ph, 5a; R = R’ = Ph, 5b; R = R’ = Me, 5c; R = R’ = Et, 5d;
R = H, R’ = 2-Me-C6H4, 5e) and equimolar amounts of C(R)(R’)Cl2. Analogously, WOCl3[κ2-{1,2-C6H4(O)-
(CHO)}], 5f, and 1,2-C6H4(OH)(CHCl2) were obtained from 1 and salicylaldehyde. The 1 : 1 reaction of 1
with acetone in CH2Cl2 resulted in the clean formation of WOCl4 and 2,2-dichloropropane. Compounds
5a,b,f were isolated as crystalline solids, whereas 5c,d,e could be detected by solution NMR only.
The interaction of 1/CH2Cl2 with isatin, in a 1 : 1 molar ratio, revealed to be a new, convenient route for
the synthesis of 3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6. The 1 : 1 reactions of 1 with R’OCH(R)CO2Me
(R = H, R’ = Me; R = Me, R’ = H) in a chlorinated solvent afforded the tungsten(V) adducts WCl4[κ2-OCH(R)-
CO2Me] (R = H, 7a; R = Me, 7b). 1/CH2Cl2 reacted sluggishly with equimolar quantities of trans-(CO2Et)-
CHvCH(CO2Et) and CH2(CO2Me)2 to give, respectively, the W(IV) derivatives WCl4[κ2-CH2(CO2Me)2], 8a,
and [WCl4-κ2-{trans-(CO2Et)CHvCH (CO2Et)}]n, 8b, in about 70% yields. The molecular structures of 2a, 3,
4, 5a, 5f, 7a and 7b were ascertained by X-ray diffraction studies.
Received 20th November 2012,
Accepted 17th December 2012
DOI: 10.1039/c2dt32771f
www.rsc.org/dalton
reside in the high moisture sensitivity of 1, which demands
accurately anhydrous reaction systems. It is significant to note
Introduction
Tungsten hexachloride, 1, is a commercial, non-expensive, that the list of crystallographically-characterized derivatives of
Lewis-acidic compound which has found large application as a WCl6 resulted from the interaction with one single organic
catalytic precursor in a variety of metal-mediated processes, reactant is, to the best of our knowledge, limited to a small
including alkyne1 or alkene polymerization,2 alkene meta- number of cases. The latter comprise a series of W(VI)
thesis3 and ring-opening polymerization.4 On account of the chloride–alkoxide complexes3d,10 and WOCl4(NCPh).11
high oxygen affinity, 1 has been successfully exploited for pro-
We became interested in the study of the interaction of
moting different types of transformations involving the acti- WCl6 with oxygen-containing species, with the aim to enlarge
vation of oxygen-containing species,5 especially the cleavage the information available on the coordination chemistry of 1.
and the coupling of C–O bonds,6 deoxygenation7 and chlori- The study gives a contribution to improve the comprehension
nation reactions.8 In spite of the variety of interesting perform- of the relevant metal-mediated organic transformations and,
ances exhibited by WCl6 in the field of metal-mediated hopefully, to help their progress. It must be mentioned here
synthesis, little is known about the coordination chemistry of that a parallel research by ourselves on the reactivity of the
this metal halide.9 A possible discouraging drawback may Group 5 metal pentahalides MX5 (M = Nb, Ta) with oxygen-
containing species allowed us to clarify the mechanistic
aspects of some MX5-directed organic reactions; furthermore
previously unknown behaviours of MX5, that are potentially
useful for future catalytic applications, were discovered.12
Reports available in the literature on the stoichiometric
reactions of 1 with oxygen-containing molecules regard alco-
hols,3d,10c long-chain esters,13 silylethers,10a,14 benzamide11
and ethyl isocyanate.15 We recently contributed by describing
the outcomes of the reactions between 1 and a number of
aUniversity of Pisa, Dipartimento di Chimica e Chimica Industriale, Via
Risorgimento 35, I-56126 Pisa, Italy. E-mail: fabmar@dcci.unipi.it;
http://www.dcci.unipi.it/~fabmar/; Tel: +39 050 2219245
bUniversity of Bologna, Dipartimento di Chimica Industriale “Toso Montanari”,
Viale Risorgimento 4, I-40136 Bologna, Italy
†CCDC 893980 (2a), 893979 (3), 893978 (4), 893977 (5a), 893974 (5f), 893976 (7a)
and 893975 (7b). For crystallographic data in CIF or other electronic format see
DOI: 10.1039/c2dt32771f
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polyethers (1,1-dialkoxyalkanes, 1,2-dialkoxyalkanes and
trimethoxymethane).16
Herein we present a systematic investigation on the reactiv-
ity of tungsten hexachloride with limited amounts of a series
of carbonyl compounds, i.e. N,N-disubstituted amides,
ketones/aldehydes and esters. The reactions have been per-
formed in a non-coordinating solvent (dichloromethane, 1,2-
dichloroethane, chloroform or the corresponding deuterated).
The metal products isolated from the distinct reactions have
been characterized by analytical and spectroscopic techniques
and, in a number of cases, by X-ray diffraction. Moreover, NMR
and GC-MS analyses have been carried out in order to eluci-
date the nature of the compounds derived from the eventual
activation of the organic material and, thus, to outline the
reaction pathways.
Fig. 1 View of the molecular structure of WOCl4(OCHNMe2), 2a. Displacement
ellipsoids are at the 50% probability level.
Table 1 Selected bond lengths (Å) and angles (°) for WOCl4(OCHNMe2), 2a
W(1)–O(1)
W(1)–Cl(1)
W(1)–Cl(3)
C(1)–O(1)
N(1)–C(2)
2.157(3)
W(1)–O(2)
W(1)–Cl(2)
W(1)–Cl(4)
C(1)–N(1)
N(1)–C(3)
1.691(3)
2.3256(10)
2.3079(10)
1.263(5)
2.3136(11)
2.3141(10)
1.297(6)
Results and discussion
1.471(5)
1.455(5)
The addition of two equivalents of HC(O)NR2 (R = Me, Et) to
dichloromethane suspensions of tungsten hexachloride, 1, O(1)–C(1)–N(1)
resulted in the slow formation of light-brown solutions. Hence
the W(VI) adducts WOCl4(OCNR2) (R = Me, 2a; R = Et, 2b)
O(1)–W(1)–O(2)
178.93(15)
122.6(4)
117(3)
W(1)–O(1)–C(1)
O(1)–C(1)–H(1)
C(1)–N(1)–C(2)
C(2)–N(1)–C(3)
134.6(3)
121(3)
121.6(4)
117.1(4)
N(1)–C(1)–H(1)
C(1)–N(1)–C(3)
121.2(4)
could be isolated in 50–60% yield after work-up, Scheme 1.
Crystals of 2a suitable for X-ray analysis were collected
from a dichloromethane–hexane mixture. Complex 2a is
is flat [mean deviation from the C(1)H(1)N(1)C(2)C(3) least
squares plane 0.0101 Å] as expected from the perfect sp2
hybridisation of C(1) [sum of the angles 361(4)°] and N(1)
[sum of the angles 359.9(7)°]. Bonding distances within the
organic ligand are as expected, with a considerable π-character
for both C(1)–O(1) [1.263(5) Å] and C(1)–N(1) [1.297(6) Å]. The
OCHNMe2 ligand in 2a is trans to the oxo ligand [O(1)–W(1)–O(2)
178.93(15)°], likewise in the above cited WOCl4(L) complexes.
An analogous configuration was found in WSCl4(thf).19
The 1H and 13C NMR spectra of 2a,b display the resonances
related to the amide ligand at higher frequencies with respect
to the situation observed in the respective non-coordinated
molecules [e.g. for 2a: δ(1H, CD3CN) = 9.03 (CH), 3.79, 3.66
(CH3) ppm; δ(13C, CD3CN) = 165.2 (CO), 49.7, 43.9 (CH3) ppm.
For non-coordinated N,N-dimethylformamide: δ(1H, CD3CN) =
7.96 (CH), 2.92, 2.80 (CH3) ppm; δ(13C, CD3CN) = 162.3 (CO),
35.6, 30.3 (CH3) ppm].
a
rare example of
a
crystallographically-characterized
W(VI) complex of formula WOCl4(L), the other examples
being WOCl4(ONPhNPh),17 WOCl4(NCPh),11 WOCl4[CF3-
C(O)CHvC(Me)N(H)(p-C6H4Br]18 and the zwitterionic
WOCl4[OvC–N(Et)-C(O)N(Et)C(CNEt)O].15
The ORTEP representation of the molecular structure of 2a
is shown in Fig. 1, whereas relevant bond lengths and angles
are reported in Table 1.
Complex 2a displays
a distorted octahedral geometry
around W(1), with the tungsten atom moved 0.257 Å apart
from the least squares plane described by the chloride ligands
towards the O(2) oxo-ligand. This is a consequence of the
double bond character of W(1)–O(2) [1.691(3) Å] compared to
the W(1)–O(1) [2.157(3) Å] single bond. The HCONC2 backbone
Furthermore, the IR spectra (solid state) confirm that the
coordination of the amide to the metal centre occurs through
the carbonylic group; indeed the stretching vibration absorp-
tion of the CvO bond appears at low wavenumber when com-
pared to the non-coordinated molecule [e.g. for 2a: νCvO
=
1653 cm−1].20 In addition the IR spectra show one strong
absorption due to the WvO stretching vibration (e.g. at
963 cm−1 in the case of 2a).21
Working under strictly anhydrous conditions, the oxo-
ligand in 2a,b is likely to be the result of chlorine–oxygen
exchange between the tungsten centre and one equivalent of
organic reactant. In order to investigate this point in more
detail, we performed an NMR study of the reactions of 1 with
HC(O)NR2 (R = Me, Et) in CD2Cl2 (see Experimental section).
These analyses revealed, in both cases, a low degree of
Scheme 1 Isolation of metal-containing products from the reactions of WCl6
with amides in dichloromethane.
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selectivity. The signals related to 2b were found in the 1H spec-
trum of 1/HC(O)NEt2; in addition a set of resonances could be
attributed to the chloroiminium cation [ClCHvNEt2]+.22 The
latter represents the organic counterpart originated from the
atom exchange. Compound 2a precipitated from the concen-
trated CD2Cl2 mixture in a nearly quantitative manner. Instead
2a was identified in a CD3CN mixture together with a set of
resonances which was tentatively assigned to [ClCHvNMe2]+.
Table 2 Selected bond lengths (Å) and angles (°) for 3. Only the data for one
of the two independent species are reported for claritya
W(1)–Cl(1)
W(1)–Cl(3)
W(1)–Cl(5)
C(11)–O(1)
C(11)–N(1)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
C(14)–N(1)
C(15)–N(1)
2.3013(13)
2.3311(15)
2.3383(13)
1.272(6)
1.295(7)
1.497(7)
1.517(9)
1.502(9)
1.449(7)
1.435(7)
W(1)–Cl(2)
W(1)–Cl(4)
W(1)–Cl(6)
C(21)–O(2)
C(21)–N(2)
C(21)–C(22)
C(22)–C(23)
C(23)–C(24)
C(24)–N(2)
C(25)–N(2)
2.3219(13)
2.3046(12)
2.3171(14)
1.271(6)
1.295(6)
1.491(7)
1.521(8)
1.513(8)
1.466(7)
1.455(7)
1
Interestingly, the H NMR spectra of the mixtures obtained
from 1/HC(O)NR2 (R = Me, Et) in CD2Cl2 displayed signifi-
cantly low field resonances (e.g. at 13.70 ppm in the case of
R = Et), which did not show correlation with any carbon in
HSQC experiment. Therefore, in the hypothesis of absence of
water, C–H bond activation might be operative to some extent
in the course of the reactions. The NMR study of the 1 : 2 reac-
tion between 1 and MeC(O)NMe2 in CD2Cl2 showed features
analogous to those described for 1/HC(O)NR2 (R = Me, Et), see
Experimental section. Unfortunately, we were not able to
isolate any pure product from 1/MeC(O)NMe2.
N(1)–C(11)–C(12)
C(11)–C(12)–C(13)
C(12)–C(13)–C(14)
C(13)–C(14)–N(1)
C(14)–N(1)–C(11)
112.1(5)
102.6(5)
105.9(5)
104.7(5)
112.2(5)
N(2)–C(21)–C(22)
C(21)–C(22)–C(23)
C(22)–C(23)–C(24)
C(23)–C(24)–N(2)
C(24)–N(2)–C(21)
111.0(5)
104.0(5)
105.7(5)
103.8(5)
113.6(4)
a Sum of the angles at: C(11) = 360.0(9)°; C(21) = 360.0(9)°; N(1) = 359.9(9)°;
N(2) = 359.8(9)°.
The cation in 3 is composed of one O-protonated N-methyl-
2-pyrrolidone molecule forming a H-bond with a second
N-methyl-2-pyrrolidone. The protonated and neutral N-methyl-
2-pyrrolidone units have rather similar bonding para-
meters, since the H(1) proton is likely to be disordered
between them.
In the IR spectrum of 3 (solid state), the absorption related
to the carbonyl moieties was found at 1626 cm−1. The 1H NMR
spectrum of 3 (in CD2Cl2) exhibited one set of broad reson-
ances, respectively, at 3.62 (2 H, CH2), 3.11 (5 H, CH2 + CH3)
and 2.30 ppm (2 H, CH2). A broad signal occurring at
13.8 ppm, ascribable to the O-bound proton, could be detected
by NMR experiment on a CD2Cl2 reaction mixture (see Exper-
imental section). The reproducible formation of 3, in an anhy-
drous system, reinforces the hypothesis that C–H activation is
a possible pathway in the course of the interaction of amides
with 1 (see above).
The study of the reactivity of 1 with amides was extended
to the cyclic amide N-methyl-2-pyrrolidone: the salt [{Ov
C–N(Me)CH2CH2CH2}2(μ-H)][WCl6], 3, was the only product
which could be isolated from the 1 : 2 molar reaction (see
Scheme 1). This compound was characterized by IR and NMR
spectroscopy, elemental analysis and X-ray diffraction. The
ORTEP representation is shown in Fig. 2, whereas relevant
bond lengths and angles are reported in Table 2.
The solid-state structure of 3 consists of an ionic packing of
[{OvC–N(Me)CH2CH2CH2}2(μ-H)]+ cations and octahedral
[WCl6]− anions. The presence of the [WCl6]− anion in 3 indi-
cates clearly that W(VI) → W(V) reduction is operative in the
course of the synthesis.
The [WCl6]− anion was previously X-ray characterized
in [AsPh4]+,23 [NEt4]+,24 Cs+,24 and [NH4]+ 25 salts. The [{Ov
C–N(Me)CH2CH2CH2}2(μ-H)]+ cation represents an uncommon
example of a crystallographically-characterized couple of carbo-
nyl compounds joined via hydrogen-bonded bridging
proton,26 although the same cation was previously found in
the tri-bromide salt [{OvC–N(Me)CH2CH2CH2}2(μ-H)][Br3].27
In accord with the report by Nielson and coworkers, the
N–H containing amide PhC(O)NH2 is susceptible to dehy-
dration upon reaction with 1 in refluxing benzene to give
almost quantitative yield of [WOCl4(NCPh)].11
On the other hand, our recent investigation on the reaction
of MeC(O)NHPh (acetanilide) with MoCl5 led to the straight-
forward synthesis of acylamidinium species via unusual inter-
molecular C–N coupling.28 In this light, we studied the reactivity
of 1 with acetanilide. The NMR spectra of the mixture
(in CD2Cl2) evidenced the low selectivity of the reaction (see
Experimental section). However the acylamidinium salt
[PhNHC(Me)N(Ph)C(O)Me][WCl6], 4, could be isolated in low
yield as a crystalline solid from a concentrated CDCl3 mixture,
see Scheme 2.
The crystal structure of 4 was determined by X-ray diffrac-
tion: the ORTEP representation is shown in Fig. 3, whereas
relevant bond lengths and angles are reported in Table 3.
The solid state structure of 4 consists of an ionic packing of
acylamidinium [PhNHC(Me)N(Ph)C(O)Me]+ cations and octa-
hedral [WCl6]− anions. The latter are rather similar to the ones
Fig. 2 View of the structure of the [{OvC–N(Me)CH2CH2CH2}2(μ-H)]+ cation in
3. Displacement ellipsoids are at the 50% probability level. Only one of the inde-
pendent cations is represented. The H-bond within the dimeric cation is rep-
resented by a dashed line.
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N(1) C(3) C(4) N(2) least square plane 0.0114 Å] and the C(2),
N(1), C(23) and N(2) centres display an almost perfect sp2
hybridisation, since their sum of the angles are all very close
to 360°.
The IR spectrum of 4 (in the solid state) displays clearly the
absorptions due to the carbonyl and iminium moieties,
respectively, at 1718 and 1623 cm−1. Major NMR features are
given by the 13C resonances at 178.3 and 171.5 ppm; these
have been attributed to the carbonyl and iminium carbons, in
agreement with the data previously reported for [MeC(O)N(Ph)-
C(Me)vNHPh][SbCl6].29
Scheme 2 WCl6-mediated synthesis of an acylamidinium cation.
The synthesis of 4 is likely to proceed analogously to that
described for the MoCl5/acetanilide system. Therefore oxygen–
chlorine exchange between the metal centre and the organic
substrate probably produces a chloroiminium intermediate
(A), see Scheme 2. The latter can then couple with one acetani-
lide molecule to yield the acylamidinium fragment, via HCl
elimination and C–N bond formation. The occurrence of the
[WCl6]− anion in the place of the expected [WOCl5]−, in the iso-
lated salt, is presumably the result of some reaction pathway
involving monoelectron reduction of W(VI) (see also the above
reaction of 1 with N-methyl-2-pyrrolidone).
The reaction of 1 with acetanilide deserves more comments.
First, it represents an easy route to the synthesis of the related
acylamidinium cation, although in modest yield. Indeed the
known synthetic protocols for the preparation of acylamidi-
nium species, including [MeC(O)N(Ph)C(Me)NHPh]+, are really
elaborated and often non-selective.29,30 Differently to what
described for the analogous reaction involving MoCl5, the acyl-
amidinium is obtained as non-coordinated in 4; this point
renders the salt as a potential reactant available for organic
chemistry.
The 1 : 2 molar reactions of WCl6 with a series of ketones/
aldehydes, in dichloromethane, afforded the oxo-tungsten(VI)
complexes WOCl4[OC(R)(R′)] in moderate-to-high yields. The
analogous reaction involving 1,2-C6H4(OH)C(O)H (salicylalde-
hyde) resulted in selective formation of WOCl3[κ2-{1,2-C6H4(O)-
(CHO)}], 5f (see Scheme 3).
Fig. 3 View of the structure of [PhNHC(Me)N(Ph)C(O)Me][WCl6], 4, with key
atoms labelled. Displacement ellipsoids are at the 50% probability level.
Table 3 Selected bond lengths (Å) and angles (°) for [PhNHC(Me)N(Ph)C(O)-
Me][WCl6], 4
W(1)–Cl(1)
W(1)–Cl(3)
W(1)–Cl(5)
C(1)–C(2)
C(2)–N(1)
N(1)–C(3)
C(3)–N(2)
2.340(5)
2.342(5)
2.305(5)
1.51(2)
1.41(2)
1.36(2)
1.31(2)
W(1)–Cl(2)
W(1)–Cl(4)
W(1)–Cl(6)
C(2)–O(1)
N(1)–C(5)
C(3)–C(4)
N(2)–C(10)
2.304(5)
2.304(5)
2.341(5)
1.214(19)
1.44(2)
1.45(2)
1.45(2)
C(1)–C(2)–O(1)
O(1)–C(2)–N(1)
C(2)–N(1)–C(5)
N(1)–C(3)–C(4)
C(4)–C(3)–N(2)
121.0(18)
122.2(18)
118.6(14)
122.2(15)
117.4(15)
C(1)–C(2)–N(1)
C(2)–N(1)–C(3)
C(5)–N(1)–C(3)
N(1)–C(3)–N(2)
C(3)–N(2)–C(10)
116.8(15)
123.1(14)
118.3(14)
120.3(15)
126.3(15)
Compounds 5a,b,f could be obtained as crystalline products
after work-up; otherwise the solid-state isolation of 5c–e failed
due to the low stability of the compounds, and their
described above for 3, being based on octahedral W(V) centre
coordinated to six chloride ligands. Other acylamidinium
cations have been previously described as partnered with
different anions,28 displaying analogous bonding parameters.
It is noteworthy that, in the present case, the [PhNHC(Me)-
N(Ph)C(O)Me]+ cation shows both an intra-molecular [N(2)–
H(2) 0.87(2) Å, H(2)⋯O(1) 1.92(14) Å, N(2)⋯O(1) 2.558(18) Å,
N(2)–H(2)–O(1) 129(15)°] and an inter-molecular [N(2)–H(2)
0.87(2) Å, H(2)⋯O(1)#1 2.33(12) Å, N(2)⋯(O(1)#1 3.03(2) Å,
N(2)–H(2)–O(1)#1 138(15)°] hydrogen bond. As a consequence
of this, the [PhNHC(Me)N(Ph)C(O)Me]+ cations form H-bonded
dimers in the solid state. The cation, excluding the phenyl
rings, is almost planar [mean deviation from the C(1) C(2) O(1)
Scheme 3 The metal products of the reactions of WCl6 with ketones/
aldehydes and salicylaldehyde in CH2Cl2.
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Table 5 Selected bond lengths (Å) and angles (°) for WOCl3[κ2-{o-OC6H4C(O)-
H}], 5f
Molecule 1
Molecule 2
W(1)–Cl(1)
W(1)–Cl(2)
W(1)–Cl(3)
W(1)–O(1)
W(1)–O(2)
W(1)–O(3)
C(1)–O(2)
C(1)–C(2)
2.324(3)
2.325(3)
2.325(3)
1.690(7)
2.257(7)
1.869(7)
1.217(13)
1.485(14)
1.412(15)
1.340(13)
163.02(10)
178.9(3)
162.3(2)
80.7(3)
2.303(3)
2.333(3)
2.321(3)
1.678(8)
2.254(7)
1.872(7)
1.227(13)
1.441(16)
1.408(15)
1.364(13)
163.02(10)
177.9(3)
163.1(2)
80.6(3)
C(2)–C(3)
C(3)–O(3)
Cl(1)–W(1)–Cl(2)
O(1)–W(1)–O(2)
Cl(3)–W(1)–O(3)
O(2)–W(1)–O(3)
W(1)–O(2)–C(1)
O(2)–C(1)–C(2)
C(1)–C(2)–C(3)
C(2)–C(3)–O(3)
C(3)–O(3)–W(1)
Fig. 4 View of the molecular structure of WOCl4[OC(Me)(Ph)], 5a. Displace-
ment ellipsoids are at the 50% probability level. Symmetry transformation used
to generate Cl(1_1) and Cl(2_1): x, −y + 1/2, z.
128.8(7)
127.2(10)
118.2(10)
123.7(9)
140.8(6)
130.2(7)
124.4(10)
122.8(10)
120.9(9)
140.8(6)
[1.690(7) and 1.678(8) Å for the two independent molecules
present in the unit cell] is the shortest W–O contact, whereas
W(1)–O(2), which is a pure coordinative bond [2.257(7) and
2.254(7) Å], is the longest one. The σ-alkoxo bond W(1)–O(3)
[1.869(7) and 1.872(7) Å] shows an intermediate value. Coordi-
nation of the bidentate κ2-{1,2-OC6H4C(O)H} ligand to W
results in a condensed metalla-bicycle composed of two six-
membered rings, which are almost planar [mean deviation
from the least square plane comprising the benzene ring, the
alkoxo and the aldehyde groups, and W: 0.0246 and 0.0229 Å
for the two independent molecules].
Fig. 5 View of the molecular structure of WOCl3[κ2-{o-OC6H4C(O)H}], 5f. Dis-
placement ellipsoids are at the 50% probability level. Only one of the two inde-
pendent molecules present within the asymmetric unit is represented.
Table 4 Selected bond lengths (Å) and angles (°) for WOCl4[OC(Me)(Ph)], 5a
W(1)–O(1)
W(1)–Cl(1)
C(1)–C(2)
C(2)–C(3)
O(1)–W(1)–O(2)
O(2)–C(2)–C(1)
C(1)–C(2)–C(3)
1.679(7)
2.295(2)
1.494(12)
1.465(13)
178.7(3)
119.7(8)
121.4(8)
W(1)–O(2)
W(1)–Cl(2)
C(2)–O(2)
2.217(6)
2.297(2)
1.247(9)
The IR spectra of 5a,b,f were recorded in the solid state: the
coordination of the carbonyl molecule to the tungsten centre
manifests itself by a considerable shift of the νCvO band to
lower wavenumbers. For instance, the CvO absorption has
been found at 1616 cm−1 in the case of 5a; the correspondent
absorption in non-coordinated acetophenone lies at
W(1)–O(2)–C(2)
O(2)–C(2)–C(3)
155.5(6)
119.0(8)
1686 cm−1 (liquid film).54
A strong IR band at about
characterization relied on solution NMR spectroscopy only. 1000 cm−1 accounts for the presence of the WvO moiety.
X-ray diffraction studies were carried out on single crystals of Compounds 5a–f were characterized in solution (CD2Cl2) by
5a and 5f: the ORTEP representations are shown in Fig. 4 and NMR spectroscopy. As expected, a significant shift to lower fre-
5, whereas relevant bond lengths and angles are reported in quencies of the 13C resonance of the carbonyl moiety is gener-
Tables 4 and 5.
ally observed, in comparison with what was reported for the
The structure of 5a is closely related to that of 2a, with aceto- corresponding uncoordinated organic molecule [e.g. for 5b:
phenone instead of dmf coordinated to the octahedral W(VI) δ(CO) = 206.0 ppm; for Ph2CO: δ(CO) = 196.5 ppm in CDCl3].
centre. Bonding parameters are similar and, in both cases, the The loss of the OH hydrogen, in the course of the reaction of 1
O-donor ligand is trans to the oxo-ligand. Conversely, 5f con- with 1,2-C6H4(OH)(CHO), is likely to occur as HCl elimination.
sists of a distorted octahedral W(VI) centre coordinated to three Indeed the formation of metal–alkoxide fragments by inter-
chloride ligands in a meridional arrangement, one oxo ligand action of WCl6 with alcohol functions via HCl release is a well-
and a bidentate κ2-{1,2-OC6H4C(O)H} alkoxo–aldehyde anionic established feature.3d,10
ligand. This situation is reminiscent of the one previously
It has to be noted that WCl6 was proposed as a stoichio-
reported for the complex WOCl3[κ2-PhNHC(O)CHC(O)Me].31 metric reagent for the chlorination of a small series of benz-
The O(1) oxo atom is trans to the aldehydic O(2), whereas the aldehydes to the corresponding gem-dichloroalkanes in
alkoxo O(3) is trans to a chloride ligand, in order to reduce refluxing CH2Cl2 (the metal products were not isolated nor
electronic competition. As expected the W(1)–O(1) oxo bond characterized).8d
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Scheme 5 Isatin chlorination by WCl6.
stoichiometric conditions (see Scheme 5).34 Indeed the 1 : 1
reaction of WCl6 with isatin, in dichloromethane, proceeded
with precipitation of an orange solid from a yellow solution.
The solid was identified as impure WOCl4 on the basis of IR
spectroscopy (see Experimental section), instead 6 was recov-
ered from the solution as a crystalline product in 49% yield.
The crystals of 6 displayed the same unit cell previously
reported in the literature, unambiguously confirming its
nature.35 In addition compound 6 was fully characterized by
1H and 13C NMR spectroscopy (CD2Cl2), and by a solid-state IR
spectrum.
It is important to notice that isatin chlorination can take
place at different sites according to the Cl-donor employed,33b–d
and the synthesis of 6 was reported only as 19% yield reaction
of isatin with PCl5.33d
In the framework of our investigation on the chemistry of 1
with carbonyl compounds, we moved to examine the reactions
of 1 with esters containing one additional function (ether,
alcohol, ester or CvC). The reactions of tungsten hexachloride
with long-chain esters (methyl palmitate, methyl 10-undeceno-
ate) were investigated previously, showing that metal mono-
electron reduction and Cl–O exchange could compete with
each other.13
The 1 : 1 reaction of 1 with methylmethoxyacetate (MeOCH2-
CO2Me) in dichloromethane proceeded sluggishly, thus
the best conditions were found by allowing the two com-
ponents to react in 1,2-dichloroethane at reflux temperature
for ca. 1 hour. After work-up, the W(V) complex WCl4-
(κ2-OCH2CO2Me), 7a, was isolated in about 60% yield as a red
crystalline solid (see Scheme 6). The synthesis of 7a was
accompanied by MeCl release, as evidenced by NMR exper-
iment in CD2Cl2 (see Experimental section). The complex
WCl4[OCH(Me)CO2Me], 7b, analogous to 7a, was obtained by
allowing a dichloromethane suspension of WCl6 to react with
D,L-Me-lactate (see Scheme 6). The formation of 7b proceeded
smoothly at room temperature with release of HCl.
Scheme 4 The two-step reaction of WCl6 with ketones.
We carried out and monitored by NMR the reactions of 1
with two equivalents of OvC(R)(R′) in CD2Cl2, in order to
prove the origin of the oxo-ligand in the products 5a–f (see
Experimental section). Hence nearly equimolar amounts of 5
and of the relevant C(R)(R′)Cl2 species were generally found,
suggesting that the synthesis of 5a–f is the result of chlorine–
oxygen exchange between the metal framework and half
organic material (Scheme 4). Moreover the NMR spectra indi-
cated that the reactions took place cleanly in most cases.
Nevertheless side-products, which could not be identified,
were recognized in the CD2Cl2 mixture resulting from addition
of acetophenone to WCl6, coherently with the low yield
achieved for the isolation of complex 5a (see Experimental
section). The relative quantity of (Me)(Ph)CCl2 was approxi-
mately found to be as double as 5a. Thus chlorine–oxygen
exchange products alternative to 5a presumably form, in
analogy with what was reported previously about the inter-
action PCl5–acetophenone.32
Similarly to what was discussed for 1/Me(Ph)CO, also the
reaction of WCl6 with Me(H)CO (acetaldehyde) is characterized
by low selectivity. Indeed the related NMR study evidenced the
formation of small amounts of MeCHCl2, together with
diverse, probable, metal-containing compounds which were
not identified (see Experimental section). Attempts of purifi-
cation by crystallization techniques were not successful.
We observed that the 1 : 1 reaction of 1 with Me2CO in
CH2Cl2 did afford one equivalent of Me2CCl2 and a solid that
was identified as WOCl4 on the basis of IR spectroscopy.47
This solid reacted very quickly with further acetone giving an
orange CH2Cl2 solution of the well-soluble complex 5c. Accord-
ingly, the formation of compounds 5 may occur in two steps,
i.e. (i) atom exchange between the metal centre and one equival-
ent of carbonyl compound, followed by (ii) coordination of the
second equivalent of organic reactant to the freshly formed
WOCl4 (see Scheme 4).
The solid state structures of 7a,b were elucidated by X-ray
diffraction studies. The respective ORTEP representations are
The results described above point out that WCl6 is able to
promote deoxygenation of amides and ketones under mild
conditions. This feature prompted us to investigate the reacti-
vity of WCl6 with 1H-indole-2,3-dione (isatin), a natural mol-
ecule which is used as a building block for the preparation of
pharmacologically-active compounds: there is great interest in
the development of effective synthetic procedures aimed at the
functionalization of isatin and its derivatives.33 We found that
WCl6 worked as a good chlorinating agent toward isatin to give
selectively 3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6, under
Scheme 6 The reactions of WCl6 with methylmethoxyacetate and D,L-lactate.
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other W(V) chloro–alkoxo complexes,36 and shorter than the
purely dative W(1)–O(2) [2.211(4) and 2.194(6) Å] interaction.
Concerning the [OCH(R)CO2Me]− (R = H, Me) alkoxy-ester
ligand, all distances are as expected, considering respectively
C(1) sp3 and C(2) sp2 hybridized.
The IR spectra of 7a,b (solid state) display the typical strong
absorption due to the coordinated carbonyl moiety (e.g. for 7b:
νCvO = 1647 cm−1; for uncoordinated D,L-Me-lactate: νCvO
=
1743 cm−1).
The 1H NMR spectrum of 7a (in CDCl3) consists of broad
resonances attributed to the methylene group (6.20 ppm) and
the methoxy unit (4.28 ppm). The former results low-field posi-
tioned as effect of the alkoxy nature of the [OCH2] moiety.
Otherwise the 13C NMR signals have been attributed as
follows: 184.3 (CvO), 78.2 (CH2), 58.7 (CH3) ppm. The
1H NMR spectrum of 7b (CDCl3) displays the resonances due
to OCH, OCH3 and C–CH3 protons respectively at 6.42, 4.33
and 1.76 ppm. The 13C NMR resonances of 7b have been
found as follows: 185.9 (CO), 86.4 (CMe), 58.1 (OCH3),
16.2 ppm (C–CH3).
Fig. 6 View of the molecular structure of WCl4(κ2-OCH2CO2Me), 7a. Displace-
ment ellipsoids are at the 50% probability level.
The W(VI)→W(V) reduction that accompanies the formation
of 7a,b takes place probably with release of elemental chlorine.
This was suggested by the formation of I2 on passing the gas
flow produced in the preparation of 7a through a concentrated
aqueous solution of KI (see Experimental section). Analogous
feature was previously hypothesized for the reactions of WCl6
with [CH3(CH2)8CH2]C(O)OMe.13
Fig. 7 View of the molecular structure of WCl4[κ2-OCH(Me)CO2Me], 7b. Dis-
placement ellipsoids are at the 50% probability level.
Table 6 Selected bond lengths (Å) and angles (°) for WCl4(κ2-OCH2CO2Me),
7a, and WCl4[κ2-OCH(Me)CO2Me], 7b
The addition of diesters (dimethylmalonate, diethylfuma-
rate) to dichloromethane suspensions of 1 resulted in very
slow formation of products which were isolated in the solid
state. In particular, the reaction of 1 with CH2(CO2Me)2
afforded, after work-up, the W(IV) complex WCl4-
[κ2-CH2(CO2Me)2], 8a, in good yield (Scheme 7). The identity of 8a
was suggested by elemental analysis data, molar conductance
and magnetic susceptibility measurement (see Experimental
section). The latter furnished a value of 1.71 BM that is signifi-
cantly lower than the spin-only value expected for a d2 system
containing two unpaired electrons. Analogous feature was pre-
viously reported for WCl4L2 complexes.37,38 The 1H and
13C NMR spectra of 8a, recorded at 193 K in order to prevent
exchange processes, displayed resonances referred to two
equivalent methoxy groups [4.16 ppm (CH3); 176.2 (CO),
58.4 ppm (CH3)], as a consequence of the bidentate co-
ordination mode of the diester ligand. Accordingly, the IR
7a
7b
W(1)–O(1)
W(1)–O(2)
W(1)–Cl(1)
W(1)–Cl(2)
W(1)–Cl(3)
W(1)–Cl(4)
C(1)–O(1)
C(1)–C(2)
1.849(4)
2.211(4)
2.2881(14)
2.173(2)
2.3574(15)
2.3306(15)
1.422(8)
1.499(9)
1.236(7)
1.289(8)
1.464(8)
75.09(17)
125.5(4)
105.6(5)
118.3(6)
116.3(5)
125.4(6)
113.5(4)
117.4(5)
1.824(7)
2.194(6)
2.292(3)
2.271(3)
2.342(3)
2.292(3)
1.421(13)
1.529(16)
1.210(12)
1.302(12)
1.464(13)
74.5(3)
126.6(6)
102.3(9)
117.9(9)
117.2(9)
124.7(10)
114.1(6)
117.7(8)
C(2)–O(2)
C(2)–O(3)
C(3)–O(3)
O(1)–W(1)–O(2)
W(1)–O(1)–C(1)
O(1)–C(1)–C(2)
C(1)–C(2)–O(2)
C(1)–C(2)–O(3)
O(2)–C(2)–O(3)
C(2)–O(2)–W(1)
C(2)–O(3)–C(3)
shown in Fig. 6 and 7, whereas relevant bond lengths and
angles are reported in Table 6.
The molecular structures of 7a and 7b are based on an octa-
hedral W(V) centre coordinated to four chlorides and a chelat-
ing anionic [OCH(R)CO2Me]− (R = H, Me) alkoxy-ester ligand,
the latter occupying two cis positions. The W–Cl contacts are
slightly spread [2.173(2)–2.3574(15) Å for 7a; 2.271(3)–2.342(3)
Å for 7b], with the shortest contact W(1)–Cl(1) [2.173(2) and
2.271(3) Å, respectively] trans to the alkoxo O(1) group. The
W(1)–O(1) contact [1.849(4) and 1.824(7) Å] is comparable with
Scheme 7 The reactions of WCl6 with diesters in dichloromethane.
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spectrum (solid state) showed one single absorption ascribed
Experimental section
General features
to the coordinated carbonyl units, at 1634 cm−1
.
The reaction of
1 with trans-(CO2Et)CHvCH(CO2Et)
resulted in the formation of the W(IV) complex [WCl4-κ2-{trans- Warning: All the metal products reported in this paper are
(CO2Et)CHvCH(CO2Et)}]n, 8b, Scheme 7. The latter compound highly moisture-sensitive, thus rigorously anhydrous con-
appears to exist as a polymer chain comprising bridging biden- ditions were required for the reaction and crystallization pro-
tate diester ligands; this feature resembles that found for ana- cedures. The reaction vessels were oven dried at 140 °C prior
logous MoCl4 derivatives39 and TiCl4–parabenzodiester to use, evacuated (10−2 mmHg) and then filled with argon.
adducts.40 Magnetic susceptibility analysis revealed the dia- WCl6, 1, was purchased from Strem (99.9% purity) and stored
magnetic nature of 8b. The IR spectrum showed absorptions in sealed glass tubes under an argon atmosphere. Once iso-
accounting for the coordinated carbonyl moieties and the lated, the metal products were conserved in sealed glass tubes
CvC functions around 1630 cm−1. The symmetric arrange- under argon. All the organic reactants were commercial pro-
ment of the fumarate ligand was corroborated by the low- ducts (Sigma Aldrich) stored under an argon atmosphere as
temperature 1H and 13C spectra (see Experimental section).
received. Solvents (Sigma Aldrich) were distilled from appropri-
It should be mentioned that the two-electron reduction of ate drying agents before use. Infrared spectra were recorded at
the W(VI) centre was claimed about the reactions of WCl6 with 298 K on an FT IR-Perkin Elmer spectrometer, equipped with a
nitriles,37 phosphines38 and sulphides.41 The thermal stability UATR sampling accessory. Magnetic susceptibilities were
of 8a,b was tested in CDCl3 solution and monitored by NMR measured at 298 K on solid samples with Magway MSB
spectroscopy. Hence compound 8b remained unchanged after Mk1 magnetic susceptibility balance (Sherwood Scientific Ltd).
heating at ca. 90 °C in a sealed NMR tube. Instead Csp3–O acti- Diamagnetic corrections were introduced according to
vation took place, under analogous conditions, in the case of König.43 NMR spectra were recorded at 293 K (unless otherwise
8a (some methyl chloride was detected in the final mixture, stated) on a Bruker Avance DRX400 instrument equipped with
see Experimental section and Scheme 7).
a BBFO broadband probe. The chemical shifts for 1H and
13C were referenced to the non-deuterated aliquot of the
1
solvent. The spectra were fully assigned via H,13C correlation
measured through gs-HSQC and gs-HMBC experiments.44 Con-
ductivity measurements were carried out on CH2Cl2 solutions
Conclusions
A systematic study on the reactivity of WCl6 with a series of car- with a Eutech Con 700 instrument (cell constant = 1.0 cm−1).45
bonyl molecules, in a non-coordinating solvent, led to the iso- GC/MS analyses were performed on an HP6890 instrument,
lation of highly moisture sensitive derivatives, which were interfaced with an MSD-HP5973 detector and equipped with a
characterized both in the solid state (X-ray, IR, elemental Phenonex Zebron column. Carbon, hydrogen and nitrogen
analysis) and in solution (NMR). The products represent analyses were performed on a Carlo Erba mod. 1106 instru-
uncommon examples of fully characterized compounds ment. The chloride content was determined by the Mohr
obtained by simple interaction of WCl6 with potential ligands method46 on solutions prepared by dissolution of the solid in
under stoichiometric conditions. The information supplied by aqueous KOH at boiling temperature, followed by cooling
this work on the coordination chemistry of WCl6 may hope- down to room temperature and addition of HNO3 up to
fully contribute to the development of WCl6-mediated organic neutralization.
synthesis.
Reactivity of WCl6 with amides
The 1 : 2 reactions of WCl6 with a number of ketones (alde-
hydes) proceed cleanly to give WOCl4(L) complexes and gem- (1) Synthesis and isolation of WOCl4(OCHNR2) (R = Me, 2a;
dichloroalkanes. This method has revealed effective for the R = Et, 2b)
synthesis of 3,3-dichloro-2,3-dihydro-1H-indol-2-one by isatin–
Compound WCl6, 1 (1.50 mmol) in CH2Cl2 (12 mL) was
WCl6 interaction. In the 1 : 2 reactions of WCl6 with N,N-disub- treated with N,N-dimethylformamide (3.10 mmol), then the
stituted amides, pathways additional/alternative to the oxygen mixture was stirred overnight at room temperature. The final
abstraction by the metal centre are operative, including W(VI) solution was concentrated under vacuum (ca. 3 mL), layered
→ W(V) reduction, C–N bond formation and, possibly, C–H with pentane (15 mL) and stored at −30 °C. The metal contain-
activation. The capability of WCl6 to activate the CvO function ing product 2a was obtained as a microcrystalline solid after
is uncommon in the context of the halides of transition 48 hours. Crystals of 2a suitable for X-ray analysis were col-
metals:34 for instance, the interactions of TiCl4 and MX5 lected from a CH2Cl2 solution layered with hexane and stored
42
(M = Nb, Ta; X = F, Cl, Br)12 with ketones and/or amides do not at −30 °C for 3 days.
affect the carbonyl moiety, in spite of the high oxidation state
WOCl4[HC(O)NMe2], 2a (yellow, 0.298 g, 48% yield). Anal.
of the metal. Instead the interactions of a variety of (di)esters Calcd for C3H7Cl4NO2W: C, 8.69; H, 1.70; N, 3.38; Cl, 34.19.
with WCl6 are dominated by the conservation of the [CvO] Found: C, 8.85; H, 1.54; N, 3.22; Cl, 33.89. 1H NMR (CD3CN)
moiety and the tendency of tungsten to achieve hexacoordina- δ = 9.03 (s, 1 H, CH); 3.79, 3.66 ppm (s, 6 H, CH3). 13C{1H}
tion: either mono- or dielectronic reduction of the metal NMR (CD3CN) δ = 165.2 (CO); 49.7, 43.9 ppm (CH3). IR (solid
centre takes place accordingly.
state): 3056w-m, 2996w, 1653vs (νCvO), 1455w, 1432m, 1358s,
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1149m, 1121m, 1032m, 963m (νWvO), 920m-s, 899m, 859w, The tube was sealed and shaken in order to homogenize the
798m, 693w cm−1
content. The tube was stored at room temperature for one
Compound 2b was obtained by a procedure similar to week. Subsequent NMR analysis was carried out.
.
that described for 2a, by allowing 1 (1.50 mmol) to react with
N,N-diethylformamide (3.00 mmol).
(a) From 1 and HC(O)NMe2 (yellow solution with abund-
ant yellow-brown precipitate). 1H NMR (CD2Cl2) δ = 17.27
WOCl4[HC(O)NEt2], 2b (yellow, 0.392 g, 59% yield). Anal. (s, 1.0 H), 10.00 (br, 2.9 H), 8.32 (s, 0.7 H), 8.12 (br, 6.2 H), 4.00
Calcd for C5H11Cl4NO2W: C, 13.56; H, 2.50; N, 3.16; Cl, 32.03. (s, 18 H), 3.1 (br, 32 H), 2.96 ppm (14 H). 13C{1H} NMR
1
Found: C, 13.69; H, 2.61; N, 3.12; Cl, 31.65. H NMR (CD2Cl2) (CD2Cl2) δ = 176.2, 167.7, 163.6 (CO); 63.6; 38.6, 34.3, 33.8,
δ = 8.94 (s, 1 H, CH); 4.29 (br, 4 H, CH2); 1.79, 1.62 ppm 32.6, 29.5 ppm (CH3).
(br, 6 H, CH3). 13C{1H} NMR (CD2Cl2) δ = 169.7 (CO); 48.3, 42.1
(b) From 1 and HC(O)NEt2 (orange solution with slight pre-
1
(CH2), 15.7, 14.0 ppm (CH3). IR (solid state): 2981w, 2940w, cipitate). H NMR (CD2Cl2) δ = 13.70 (s, 1.0 H), 8.94 (br, 2.1 H,
1628s (νCvO), 1462m, 1445m, 1378w-m, 1360w-m, 1306w, 2b), 7.92 [br, 2.0 H, ClCHvN(CH2CH3)2], 4.29 (s, 7.5 H, 2b),
1278w, 1205m, 1103m, 1017m, 958s (νWvO), 913s, 877s, 811m-s, 3.65 [br, 6.8 H, ClCHvN(CH2CH3)2], 1.79 (s, 6.3 H, 2b), 1.62
742vs cm−1
.
(s, 5.9 H, 2b), 1.46 [s, 5.0 H, ClCHvN(CH2CH3)2], 1.41 [s, 5.2
(2) Synthesis and isolation of [{OvC–N(Me)CH2CH2CH2}2- H, ClCHvN(CH2CH3)2] ppm. 13C{1H} NMR (CD2Cl2) δ = 198.7,
(μ-H)][WCl6], 3
169.7 (CO); 69.4; 48.3, 42.1, 19.8, 15.7, 14.0 ppm (CH3).
Compound 3 was prepared by allowing 1 (1.20 mmol) to
(c) From 1 and N-methyl-2-pyrrolidone (green-brown solu-
react with N-methyl-2-pyrrolidone (2.40 mmol) in dichloro- tion with slight precipitate). 1H NMR (CD2Cl2) δ = 13.8 (v-br,
methane (15 mL). The mixture was stirred at room temperature 0.5 H), 5.04 (0.2 H), 4.90 (0.2 H), 4.57 (0.3 H), 4.42 (0.5 H), 3.84
for 18 hours. The resulting dark-green solution was concen- (2.6 H), 3.77 (1.1 H), 3.66 (2.1 H), 3.22 (4.8 H), 3.09 (4.3 H),
trated under vacuum and then stored at −30 °C for 48 h, 2.68 (0.9 H), 2.57 (1.4 H), 2.40 (1.9 H). 13C{1H} NMR (CD2Cl2)
hence a dark green-brown precipitate (compound 3) formed. δ = 173.6, 172.6, 171.9 (CO); 53.0, 52.0, 35.1, 14.2 (CH2);
Crystals suitable for X-ray analysis were collected from a 33.0 ppm (Me). The addition of cyclopentene (0.30 mmol) to
dichloromethane solution layered with hexane and stored at this mixture at ca. −70 °C gave a solution which was stored in
−30 °C for 48 hours. Yield 0.306 g, 43%. Anal. Calcd for a sealed NMR tube at room temperature, and analyzed by
C10H19Cl6N2O2W: C, 20.16; H, 3.21; N, 4.70; Cl, 35.70. Found: NMR after 24 h. Thus cyclopentene and Cl-cyclopentane were
1
C, 20.03; H, 3.34; N, 4.83; Cl, 35.91. H NMR (CD2Cl2) δ = 3.62 recognized in ca. 1 : 1 ratio.
(br, 2 H, CH2); 3.11 (br, 5 H, CH2 + CH3); 2.30 ppm (br, 2 H,
(d) From 1 and MeC(O)NHPh (dark brown solution
CH2); OH not observed. 13C{1H} NMR (CD2Cl2) δ = 172.6 (CO); with yellow-green precipitate). 1H NMR (CD2Cl2) δ = 14.00
51.7, 32.8, 13.9 (CH2); 32.1 ppm (Me). IR (solid state): 2963w, (br, minor), 9.86 (br, 1.0 H), 7.79–7.36 (Ph), 2.60 (br, 2.8 H),
2931w, 2889w, 1704w, 1665w-m, 1626vs (νCvO), 1557w-m, 2.41 (br, 0.8 H), 2.22 (br, 0.7 H), 2.15 (br, 0.8 H) ppm. 13C{1H}
1512m, 1479m, 1449m, 1408m, 1310m, 1258m, 1230w, NMR (CD2Cl2) δ = 211.4, 179.2, 174.2, 171.7 (CO); 136.6–123.7
1098s, 1043s, 1014m, 974m-s, 940m-s, 859vs, 798vs, 757vs, (Ph), 30.0, 27.2, 23.1 ppm.
675s cm−1
(3) Synthesis and isolation of [PhNHC(Me)N(Ph)C(O)Me]- brown precipitate). H NMR (CD2Cl2) δ = 12.19 (s, 1.0 H), 4.59
.
(e) From 1 and MeC(O)NMe2 (dark-yellow solution with
1
[WCl6], 4
(br, 0.5 H), 4.41 (s, 0.5 H), 4.01 (br, 4.0 H), 3.42 (s, 26 H), 3.23
Compound 4 was isolated as follows. WCl6, 1 (1.10 mmol), (br, 3 H), 2.70 ppm (12 H). 13C{1H} NMR (CD2Cl2) δ = 179.5,
in CDCl3 (1.5 mL) was treated with acetanilide (2.20 mmol) 175.5 (CO); 59.4, 57.0, 44.4 (br), 41.2, 37.5, 23.2, 16.6 ppm.
inside a Schlenk tube. The mixture was stirred for 2 days at
The reaction of 1 (0.45 mmol) with dmf (0.45 mmol) in
room temperature. The final solution was stored at −30 °C for CD3CN in a sealed NMR tube gave a dark yellow solution with
one week, thus yellow crystals of 4 were obtained. The crystals a slight precipitate, after 8 days. 1H NMR (CD3CN) δ = 15.91
were separated from the solution and dried under vacuum. (br), 9.82 [br, ClCHvNMe2], 9.03 (s, 1.0 H, 2a), 8.60 (s, 0.1 H),
Yield: 0.214 g, 30%. Anal. Calcd for C16H17Cl6N2OW: C, 29.57; 8.55 (s, 0.1 H), 8.53 (s, 0.2 H), 8.46 (s, 0.3 H), 8.33 (s, 0.9 H),
H, 2.64; N, 4.31; Cl, 32.73. Found: C, 29.22; H, 2.70; N, 4.26; 8.25 (s, 0.3 H), 3.81 (s, 3 H, 2a), 3.68 (s, 3 H, 2a), 3.49 [s, 0.9 H,
Cl, 32.33. 1H NMR (CD3CN) δ = 10.95 (s-br, 1 H, NH), 7.71, ClCHvNMe2], 3.33 (s, 0.8 H), 3.31 (s, 5.2 H), 3.26 (s, 0.6 H),
7.61, 7.48 (10 H, arom CH); 2.13, 2.00 ppm (s, 6 H, Me). 3.22 (s, 1.1 H), 3.19 (s, 2.8 H), 3.16 ppm (s, 0.9 H). 13C{1H}
13C{1H} NMR (CD3CN) δ = 178.3, 171.5 (CvO + CvN); 137.3, NMR (CD3CN)
δ = 195.7, 168.7, 167.7, 167.3, 166.8
134.6, 132.2, 131.9, 130.9, 129.3, 128.3, 123.5 (arom CH); 28.9, [ClCHvNMe2], 165.7 (2a), 153.7, 48.5 (2a), 47.7, 47.1
24.0 ppm (Me). IR (solid state): 3103w (νN–H), 3046w, 2935w, [ClCHvNMe2], 43.7 (2a), 42.5, 41.6, 37.6, 36.7, 36.2 ppm.
1718s (νCvO), 1623s (νCvN), 1588s, 1489m, 1468m, 1418w,
Reactivity of WCl6 with ketones/aldehydes
1367s, 1310m, 1227s, 1178vs, 1030m, 1001w, 972w-m, 913m,
849m, 830m, 756s, 721s, 693vs cm−1
.
(1) Synthesis and isolation of WOCl4[OC(Me)(Ph)], 5a,
WOCl4[OCPh2], 5b, and WOCl3[κ2-{1,2-C6H4(O)(CHO)}], 5f
Tungsten hexachloride (1.20 mmol) in CH2Cl2 (12 mL) was
(4) NMR studies
General procedure: Tungsten hexachloride (0.35 mmol) was
introduced into an NMR tube. Then CD2Cl2 (0.70 mL) and the treated in a Schlenk tube with the appropriate organic reactant
appropriate amide (0.70 mmol) were added in the order given. (2.50 mmol). The mixture was stirred for 18 hours. The final
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solution was filtrated in order to remove the solid, and concen-
(b) From WCl6 and Ph2CO (orange solution): 5b and
trated up to ca. 4 mL. The solution was layered with hexane Ph2CCl2 in
a
1 : 0.9 ratio. Ph2CCl2: 1H NMR (CD2Cl2)
(10 mL), and the tube was stored at −30 °C. The product was δ = 7.70–7.44 ppm (m, Ph).49 13C NMR{1H} (CD2Cl2) δ = 144.1
collected as a crystalline solid after one week.
(ipso-Ph); 129.2, 128.2, 127.4 (arom CH); 92.2 ppm (CCl2).50
5a (green). Yield: 0.194 g, 35%. Anal. Calcd for
(c) From WCl6 and Me2CO (brown solution): 5c and
1
C8H8Cl4O2W: C, 20.81; H, 1.75; Cl, 30.71. Found: C, 20.98; H, Me2CCl2 in a 1 : 1 ratio. 5c: H NMR (CD2Cl2) δ = 2.74 (s, Me)
1.60; Cl, 30.34. 1H NMR (CD2Cl2) δ = 8.33–7.63 (5 H, Ph); ppm. 13C NMR{1H} (CD2Cl2) δ 225.8 (CO); 32.4 ppm (Me).
3.17 ppm (s, 3 H, Me). 13C{1H} NMR (CD2Cl2) δ = 210.3 (CO); Me2CCl2: 1H NMR (CD2Cl2) δ = 2.23 (s, Me) ppm. 13C NMR{1H}
137.0, 130.9, 129.4 (Ph); 135.8 (ipso-Ph); 25.4 ppm (Me). IR (CD2Cl2) δ = 86.5 (CCl2); 39.1 ppm (Me).51 The addition of
(solid state): 3065w, 2919w, 1616vs (νCvO), 1591vs, 1570vs, cyclopentene (0.50 mmol) to the mixture at ca. −70 °C gave a
1489w, 1448m, 1357m, 1317w, 1290s, 1239w, 1181m, 1101w-m, solution which was stored in a sealed NMR tube at room
1001vs (νWvO), 970s, 763vs, 744m, 678s.
temperature, and analyzed by NMR after 24 h. Products of
5b (red). Yield: 0.497 g, 79%. Anal. Calcd for C13H10Cl4O2W: Cl-addition to cyclopentene were not recognized.
C, 29.81; H, 1.92; Cl, 27.07. Found: C, 29.52; H, 2.07; Cl, 26.63.
(d) From WCl6 and Et2CO (dark-orange solution): 5d and
1H NMR (CD2Cl2) δ = 8.11, 7.84, 7.66 ppm (m, Ph). 13C{1H} Et2CCl2 in a 1 : 0.8 ratio. 5d: 1H NMR (CD2Cl2) δ = 2.99 (br,
NMR (CD2Cl2) δ = 206.0 (CO); 135.8, 133.3, 128.8 (Ph); 2 H, CH2); 1.36 (br, 3 H, CH3) ppm. 13C NMR{1H} (CD2Cl2)
135.2 ppm (ipso-Ph). IR (solid state): 3057w, 1584s, 1549vs δ = 230.5 (CO); 37.1 (CH2); 9.0 ppm (CH3). Et2CCl2: 1H NMR
3
3
(νCvO), 1490m, 1446m-s, 1326vs, 1287s, 1187m, 1179m, (CD2Cl2) δ = 2.28 (q, JHH = 7.2 Hz, CH2); 1.23 ppm (t, JHH
=
1160m, 1089w, 1075w, 1026w, 994vs (νWvO), 940m, 921s, 7.2 Hz, CH3). 13C NMR{1H} (CD2Cl2) δ 97.9 (CCl2); 40.9 (CH2);
839m, 807m, 764s, 690vs, 675s.
9.7 ppm (CH3).
5f (dark red). Yield: 0.405 g, 79%. Anal. Calcd for
(e) From WCl6 and 1,2-C6H4(Me)(CHO) (ortho-tolylaldehyde;
C7H5Cl3O3W: C, 19.68; H, 1.18; Cl, 24.89. Found: C, 19.89; H, yellow mixture): 5e and 1,2-C6H4(Me)(CHCl2) in a 1 : 1 ratio. 5e:
1.02; Cl, 24.60. 1H NMR (CD2Cl2) δ = 9.83 (s, 1 H, HCvO); 1H NMR (CD2Cl2) δ = 10.23 (s, 1 H, CHO); 7.93–7.25 (m, 4 H,
8.10, 7.54, 7.26 ppm (m, 4 H, Ph). 13C{1H} NMR (CD2Cl2) CH); 2.75 ppm (s, 3 H, CH3). 13C NMR{1H} (CD2Cl2) δ = 196.6
δ = 195.4 (HCO); 157.3 (arom CO); 140.6, 137.6, 129.8, 122.2 (CO); 142.5 (C–Me); 135.5 (C–COH); 133.3, 133.2, 132.1, 126.8
(arom CH); 125.7 ppm (C–CO). IR (solid state): 2928w, 1630w-m, (arom CH); 19.8 ppm (Me). 1,2-C6H4(Me)(CHCl2): 1H NMR
1617s, 1589vs (νCvO), 1557vs, 1474m, 1445m, 1399m, 1328m, (CD2Cl2) δ = 7.84–7.24 (m, 4 H, arom CH); 7.04 (s, 1 H, CHCl2),
1265m, 1238vs, 1221s, 1160m, 1116m, 1094w, 994vs (νWvO), 2.50 ppm (s, 3 H, Me). 13C NMR{1H} (CD2Cl2) δ = 138.2 (C–Me);
953w, 918s, 814s, 769s, 760vs, 661m.
133.0 (C–CCl2); 130.8, 129.9, 127.8 (Ph); 69.9 (CCl2); 18.6 ppm
The mixture of 1 (0.50 mmol), CHCl3 (0.50 mmol) and (Me).52
Me2CO (0.50 mmol) in CH2Cl2 (10 mL) was stirred for 18 h.
(f) From WCl6 and 1,2-C6H4(OH)(CHO) (salicylaldehyde;53
Then the resulting solution was separated from a brown solid. red solution): 5f and 1,2-C6H4(OH)(CHCl2) in a 1 : 1 ratio.
The IR spectrum of the solid presented a strong absorption at 1,2-C6H4(OH)(CHCl2): 1H NMR (CD2Cl2) δ = 10.90 (s, 1 H, OH),
47
980 cm−1, attributed to WOCl4
(Anal. Calcd for Cl4OW: 8.09–6.96 (m, 4 H, arom CH), 6.44 ppm (s, 1 H, CHCl2).
Cl, 41.51. Found: Cl, 42.74). An aliquot of the solution
(g) From WCl6 and Me(H)CO (dark-yellow solution).
(0.50 mL) was added to CD2Cl2 (0.40 mL) and analyzed by 1H NMR (CD2Cl2) δ = 10.23 (s), 5.98 (MeCHCl2 54), 2.78–1.27
1H NMR: Me2CCl2 and CHCl3 were recognized in a 0.8 : 1 (broad envelope of resonances) ppm. 13C NMR{1H} (CD2Cl2)
ratio.
(2) NMR studies. Characterization of WOCl4[OC(R)(R′)] 25.7, 20.3 ppm. After hydrolysis (brown solution), MeCHO and
(R = R′ = Me, 5c; R = R′ = Et, 5d; R = H, R′ = 2-Me-C6H4, 5e)
MeCHCl2 were recovered in ca. 2 : 1 ratio (1H NMR), in admix-
δ = 216.3, 90.1, 71.0 (MeCHCl2), 58.1, 48.3, 31.2 (MeCHCl2),
A mixture of WCl6 (0.500 mmol) and CD2Cl2 (0.70 mL), in ture with non-identified compounds.
an NMR tube, was treated with the appropriate ketone (alde-
Reactivity of WCl6 with isatin;55 synthesis and isolation of
3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6
hyde). Then the tube was sealed and shaken in order to homo-
genize the content. The tube was stored at room temperature;
after ca. 1 week NMR spectra of the resulting mixtures were Isatin (0.700 mmol) was added to WCl6 (0.700 mmol) in
recorded. Afterwards, H2O (ca. 5 mmol) was added in selected CH2Cl2 (15 mL). The mixture was stirred for 36 hours. The
cases, resulting in the quick precipitation of a dark solid. The resulting yellow solution was separated from an orange precipi-
latter was separated from the solution, which was analyzed by tate. The IR spectrum of the precipitate displayed an intense
NMR/GC-MS.
band at 980 cm−1, attributed to WOCl4.47 The solution was
(a) From WCl6 and (Me)(Ph)CO (dark-yellow solution): 5a transferred into a Schlenk tube, concentrated to ca. 4 mL and
and (Me)(Ph)CCl2 in a 1 : 1.8 ratio. (Me)(Ph)CCl2: 1H NMR layered with hexane. The tube was stored at −30 °C, thus crys-
(CD2Cl2) δ = 2.51 ppm (s, Me).48 13C NMR{1H} (CD2Cl2) tals of 6 were collected after 5 days. Yield: 0.069 g, 49%. Anal.
δ = 93.0 ppm (CCl2). Minor signals at 4.18 (br), 4.02 (br), 2.80 Calcd for C8H5Cl2NO: C, 47.56; H, 2.49; N, 6.93. Found:
1
(s) and 2.11 (s) ppm were found in the 1H spectrum. After C, 47.73; H, 2.35; Cl, 7.01. H NMR (CD2Cl2) δ = 8.48 (s, 1 H,
hydrolysis (red solution), Me(Ph)CO was the only species NH); 7.66, 7.41, 7.24, 7.06 (4 H, Ph) ppm. 13C{1H} NMR
which could be recognized.
(CD2Cl2) δ = 170.3 (CO); 138.9, 137.8 (arom C); 132.1, 125.0,
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124.3, 111.2 (arom CH); 74.6 (CCl2) ppm. IR (solid state): C, 13.12; H, 1.76; Cl, 30.98. Found: C, 12.66; H, 1.84; Cl, 30.22.
3176w-m (νN–H), 3112w, 1736vs (νCvO), 1692w-m, 1614s, 1471s, 1H NMR (CD2Cl2, 193 K) δ = 4.16 (s, 6 H, CH3); 3.95 (s, 2 H,
1393m, 1325w-m, 1262w, 1238w, 1182m, 1100w-m, 989m, CH2) ppm. 13C{1H} NMR (CD2Cl2, 193 K) δ = 176.2 (CO); 58.4
916w, 870w-m, 835m-s.
(CH3); 14.3 (CH2) ppm. IR (solid state): 2963m, 1634s (νCvO),
1462m, 1443w-m, 1408w, 1376w-m, 1310m, 1258s, 1083s,
1015vs, 1003vs, 855m, 789vs, 685m, 659m. ΛM = 0.3 S cm2
Synthesis of WCl4[κ2-OCH(R)CO2Me] (R = H, 7a; R = Me, 7b)
(1) WCl6 (0.700 mmol) was allowed to react with MeOC(O)- mol−1. Magnetic measurement: χcMorr = 1.21 × 10−3 cgsu, μeff
=
CH2OMe (0.80 mmol) in boiling 1,2-dichloroethane (15 mL) 1.71 BM.
for 1 hour. The resulting red solution was concentrated to ca.
8b (ochre yellow solid), from WCl6 and trans-(CO2Et)-
3 mL and layered with heptane. Thus compound 7a was CHvCH(CO2Et). Reaction time = 50 days, yield = 72%. Anal.
obtained as a crystalline red solid upon storing the mixture at Calcd for C8H12Cl4O4W: C, 19.30; H, 2.43; Cl, 28.49. Found:
1
−30 °C for 72 hours. Yield: 0.171 g, 59%. Anal. Calcd for C, 19.66; H, 2.29; Cl, 27.75. H NMR (CD2Cl2, 193 K) δ = 7.45
C3H5Cl4O3W: C, 8.69; H, 1.22; Cl, 34.19. Found: C, 8.90; H, (s, 2 H, CH); 4.69 (m, 4 H, CH2); 1.49 (m, 6 H, CH3) ppm.
1.04; Cl, 33.78. 1H NMR (CDCl3) δ = 6.20 (s, 2 H, CH2); 13C{1H} NMR (CD2Cl2, 193 K) δ = 169.2 (CO); 134.5 (CH); 66.6
4.28 ppm (s, 3 H, CH3). 13C{1H} NMR (CDCl3) δ = 184.3 (CvO); (CH2); 13.8 (CH3) ppm. IR (solid state): 3098w, 2985w, 1781w,
78.2 (CH2); 58.7 (CH3) ppm. IR (solid state): 2961w, 2907w, 1634vs (νCvC), 1623s-sh (νCvO), 1581w, 1462m, 1443w, 1397w,
1647s (νCvO), 1621vs, 1467s, 1387vs, 1293m, 1203w-m, 1067vs 1377m, 1311s, 1285w, 1240m, 1186w, 1094m, 1019w-m,
(νC–O), 996s, 961s, 899m-s, 726m.
Compound 7b was prepared by allowing WCl6
(0.800 mmol), in a suspension of CH2Cl2 (10 mL), to react with
1003vs, 977m, 958w, 855m, 773m. ΛM = 0.4 S cm2 mol−1
(2) NMR studies.
.
General procedure: WCl6 (0.350 mmol), CDCl3 (0.70 mL)
D,L-HOCH(Me)CO2Me (D,L-methyl lactate) for 18 hours. Gas and the appropriate organic reactant (0.350 mmol) were intro-
release occurred in the course of the reaction (the gas flow duced into an NMR tube in the order given. The tube was
determined the formation of a precipitate from aqueous sealed and shaken in order to homogenize the content. Then
AgNO3 solution). The resulting orange solution was concen- the sample was stored at room temperature for 3 days. An
trated to 3 mL and layered with hexane, hence crystals suitable orange solution formed over a black solid. 1H NMR analysis
for X-ray analysis were collected after one week at −30 °C. evidenced the absence of the organic reactant and the for-
Yield: 0.230 g, 67%. Anal. Calcd for C4H7Cl4O3W: C, 11.21; mation of 8a-b. Then the tube was heated at ca. 90 °C for 2 h.
1
H, 1.65; Cl, 33.08. Found: C, 11.03; H, 1.79; Cl, 33.32. H NMR The resulting mixture was treated with a large excess of water
(CDCl3) δ = 6.42 (s, 1 H, OCH); 4.33 (s, 3 H, OCH3); 1.76 ppm (ca. 10 mmol). The solution was separated from the solid and
(s, 3 H, C–CH3). 13C{1H} NMR (CDCl3) δ = 185.9 (CO); 86.4 analyzed by NMR and GC/MS.
(CMe); 58.1 (OCH3); 16.2 ppm (C–CH3). IR (solid state):
(a) From WCl6 and CH2(CO2Me)2: CH2(CO2Me)2 and MeCl
ν = 2930w, 1650vs (νCvO), 1588s, 1465m, 1386m, 1265w-m, (ratio 10 : 8).
1103m, 1050m, 999m, 891vs, 780vs.
(b) From WCl6 and trans-(EtO2C)CHvCH(CO2Et): trans-
(2) NMR study. A mixture of WCl6 (0.500 mmol) and CD2Cl2 (EtO2C)CHvCH(CO2Et).
(0.70 mL), in an NMR tube, was treated with MeOC(O)CH2OMe
(0.80 mmol). Then the tube was sealed and shaken in order to
X-ray crystallographic study
homogenize the content. The tube was stored at room temp-
erature; after 4 weeks, NMR spectra of the resulting mixture Crystal data and collection details for 2a, 3, 4, 5a, 5f, 7a and 7b
were recorded. Thus compound 7a, MeCl and CHCl3 were are reported in Table 7. The diffraction experiments were
recognized in about 0.8 : 0.8 : 1 ratio. When the tube was carried out on a Bruker APEX II diffractometer equipped with
opened, gas flow occurred; the gas determined formation of I2 a CCD detector using Mo-Kα radiation. Data were corrected for
from a concentrated aqueous solution of KI.
Lorentz polarization and absorption effects (empirical absorp-
tion correction SADABS).56 Structures were solved by direct
methods and refined by full-matrix least-squares based on all
data using F2.57 All non-hydrogen atoms were refined with an-
isotropic displacement parameters. Hydrogen atoms were fixed
at calculated positions and refined by a riding model, except
Reactivity of WCl6 with CH2(CO2Me)2 and trans-(CO2Et)-
CHvCH(CO2Et). Synthesis and isolation of WCl4-
[κ2-CH2(CO2Me)2], 8a, and [WCl4-κ2-{trans-(CO2Et)-
CHvCH(CO2Et)}]∞, 8b
(1) A suspension of WCl6 (1.20 mmol) in CH2Cl2 (15 mL) was H(1) [bonded to C(1)] in 2a and H(2) [bonded to N(2)] in 4
added to the appropriate organic reactant (1.25 mmol). The which have been located in the Fourier map.
mixture was stirred at room temperature for variable time.
The asymmetric units of 3 contain one full (located in a
Then the volatile materials were removed under vacuum, and general position) and two halves (on mirror planes) of [WCl6]−
the resulting residue was washed abundantly with cyclo- anions and two [{OvC–N(Me)CH2CH2CH2}2(μ-H)]+ cations
hexane. The solid was dried under vacuum before (located in general positions). These cations are constituted by
characterization.
two OvC–N(Me)CH2CH2CH2 rings joined by a H-bond.
8a (ochre yellow solid), from WCl6 and CH2(CO2Me)2. Reac- The protonated part of one of the two independent cations is
tion time = 50 days, yield = 70%. Anal. Calcd for C5H8Cl4O4W: disordered over two positions; disordered atomic positions
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Table 7 Crystal data and experimental details for WOCl4[HC(O)NMe2], 2a, [{OvC–N(Me)CH2CH2CH2}2(μ-H)][WCl6], 3, [PhNHC(Me)N(Ph)C(O)Me][WCl6], 4,
WOCl4[OC(Me)(Ph)], 5a, WOCl3[κ2-{o-OC6H4C(O)H}], 5f, WCl4[κ2-OCH(R)CO2Me] (R = H, 7a; R = Me, 7b)
Complex
2a
3
4
5a
5f
7a
7b
Formula
Fw
T (K)
C3H7Cl4NO2W
414.75
100(2)
C10H19Cl6N2O2W C16H17Cl6N2OW C8H8Cl4O2W
C7H5Cl3O3W
427.31
100(2)
C3H5Cl4NO3W
414.72
100(2)
C4H7Cl4NO3W
428.75
100(2)
595.82
150(2)
649.87
100(2)
461.79
100(2)
λ (Å)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
0.71073
Orthorhombic
P212121
6.3608(4)
9.9793(7)
16.0433(11)
90
1018.37(12)
4
2.705
0.71073
Orthorhombic
Pnma
19.219(4)
29.661(6)
13.226(3)
90
7540(3)
16
2.100
0.71073
Monoclinic
P21/n
14.390(10)
9.985(7)
16.622(11)
110.196(9)
2241(3)
4
0.71073
Orthorhombic
Pnma
20.190(14)
7.212(5)
8.608(6)
90
1253.5(14)
4
2.447
0.71073
Monoclinic
C2/c
25.582(7)
10.818(3)
18.629(5)
123.914(3)
4278(2)
16
0.71073
Monoclinic
C2/c
18.305(4)
9.7756(19)
12.088(2)
120.147(2)
1870.5(6)
8
0.71073
Monoclinic
Cc
10.2279(18)
8.4464(15)
12.946(2)
109.452(2)
1054.6(3)
4
β (°)
Cell volume (Å3)
Z
Dc (g cm−3
)
1.926
5.877
1244
2.654
11.524
3136
2.945
13.450
1512
2.700
11.932
788
μ (mm−1
F (000)
)
12.347
760
6.981
4560
10.043
856
Crystal size (mm) 0.16 × 0.13 ×
0.11
0.19 × 0.12 × 0.10 0.19 × 0.13 ×
0.11
0.18 × 0.16 ×
0.12
2.57–25.99
8205
0.21 × 0.19 ×
0.15
1.92–25.03
14 605
0.16 × 0.15 ×
0.14
2.45–26.99
7541
0.17 × 0.15 ×
0.11
3.21–26.00
3908
θ limits (°)
Reflections
collected
2.40–27.99
28 799
1.37–25.66
1.62–25.02
11 489
72 771
Independent
reflections
Data/restraints/
parameters
Goodness on fit
on F2
2384 [Rint
0.0221]
2384/1/104
=
7274 [Rint
0.0605]
7274/342/461
=
3877 [Rint
0.1656]
3877/85/238
=
1330 [Rint
0.0834]
1330/0/86
=
3789 [Rint
0.864
3789/0/253
=
2039 [Rint
0.0200]
2039/0/100
=
2015 [Rint =
0.0435]
2015/63/119
1.058
1.023
0.955
1.098
1.006
1.244
0.989
R1 (I > 2σ(I))
wR2 (all data)
0.0166
0.0386
0.0279
0.0668
0.0695
0.1873
0.0345
0.0812
0.0439
0.1175
0.0271
0.0616
0.0334
0.0733
Largest diff. peak 0.838/−0.674
1.981/−0.753
2.301/−1.677
1.017/−1.390
3.303/−1.429 1.291/−2.059
1.693/−1.726
and hole (e Å−3
)
were split and refined isotropically using one occupancy para-
meter per disordered group.
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Acknowledgements
The authors wish to thank the Ministero Istruzione, Università e
Ricerca (2009 PRIN project: ‘New strategies for the control of
reactions: interactions of molecular fragments with metallic
sites in unconventional species’) for financial support.
5646 | Dalton Trans., 2013, 42, 5635–5648
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