One pot synthesis of η3-butadienyl complexes of Mo(II) or W(II): Crystal structure of [MoCl(CO)2(η3-CH2C(CONHCH 2C{triple bond, long}CH)C{double bond, long}CH2)(2,2′-bipyridine)]

Article abstract of DOI:10.1016/j.poly.2006.10.040

A one pot reaction of [M(CO)₄L₂] (M = Mo, L₂ = 2,2′-bipyridine, 1,10-phenanthroline; M = W, L₂ = 2,9-dimethyl-1,10-phenanthroline) with 1,4-dichloro-2-butyne and Ph₄PCl was examined in chlorinated solvents over the range 40-129 °C. Production of either [MCl(CO)₂(η³-CH₂C(COCl)C{double bond, long}CH₂)L₂] (4) or [MCl₂(CO)(η²-ClCH₂C{triple bond, long}CCH₂Cl)L₂] was found to be dependent upon the solvent temperature, and these reactions were found to be insensitive to the presence of water. Under controlled conditions, one pot reactions carried out in the presence of alcohols, amines or thiols gave related ester, amide or thioester substituted η³-butadienyl complexes in good yield. The structure of the propargyl amide complex was confirmed by X-ray analysis.

Full text of DOI:10.1016/j.poly.2006.10.040

Polyhedron 26 (2007) 1285–1291
www.elsevier.com/locate/poly
One pot synthesis of g3-butadienyl complexes
of Mo(II) or W(II): Crystal structure of
[MoCl(CO)2(g3-CH2C(CONHCH2C„CH)C@CH2)(2,20-bipyridine)]
a,
b
b
Annabelle G.W. Hodson *, Simon J. Coles , Michael B. Hursthouse
a
Faculty of Applied Sciences, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK
b
School of Chemistry, University of Southampton, University Road, Highfield SO17 1BJ, UK
Received 25 July 2006; accepted 25 October 2006
Available online 10 November 2006
Abstract
A one pot reaction of [M(CO)4L2] (M = Mo, L2 = 2,20-bipyridine, 1,10-phenanthroline; M = W, L2 = 2,9-dimethyl-1,10-phenanthro-
line) with 1,4-dichloro-2-butyne and Ph4PCl was examined in chlorinated solvents over the range 40–129 ꢀC. Production of either
[MCl(CO)2(g3-CH2C(COCl)C@CH2)L2] (4) or [MCl2(CO)(g2-ClCH2C„CCH2Cl)L2] was found to be dependent upon the solvent tem-
perature, and these reactions were found to be insensitive to the presence of water. Under controlled conditions, one pot reactions carried
out in the presence of alcohols, amines or thiols gave related ester, amide or thioester substituted g3-butadienyl complexes in good yield.
The structure of the propargyl amide complex was confirmed by X-ray analysis.
ꢁ 2006 Elsevier Ltd. All rights reserved.
Keywords: One pot; Molybdenum; Tungsten; Butadienyl; Alkyne; Water
1. Introduction
of [MoCl(CO)2(g3-CH2C(COCl)C@CH2)(phen)] in good
yield from reactions of 1,4-dichloro-2-butyne and
Ph4P[MoCl(CO)3(phen)] in either CH2Cl2 or water [6]. This
acyl chloride complex was found to be stable when sus-
pended in water for several hours, and could be handled
in air for short periods with minimal oxidation. Whilst
the tungsten analogue could be isolated in chlorinated sol-
vents, the reaction proved more sensitive to water and
yielded the alternative product [WCl2(CO)3(phen)]. Pro-
duction of the precursor complex Ph4P[MCl(CO)3(phen)]
occurred in a two step process, involving refluxing the
metal hexacarbonyl and L2 in toluene (Mo) or xylene
(W), followed by heating the product [M(CO)4L2] with
Ph4PCl in the same solvent and acetonitrile. In an attempt
to improve yields, and to reduce the overall reaction time
for the three stage conversion of [M(CO)6] to the butadie-
nyl (Mo 5 h, W 20 h), one pot reactions of these reagents
have been investigated in chlorinated solvents or in water
over the temperature range 40–129 ꢀC.
Transition metal complexes containing g3-dienyl ligands
are important, because of their relationships to g2-diynes,
g3-allyls and g4-dienes, and for their roles as key interme-
diates in certain catalytic processes [1–3]. Synthesis of these
complexes typically requires exclusion of moisture due to
the sensitivity of reactants, intermediates and products to
water, and many are carried out in dried ethers or chlori-
nated solvents. For example, substituted complexes of the
type [Mo(CO)2(g3-CH2CHC@CR1R2)L3] (R1,R2 = H,
Me) have been obtained by reaction of electrophilic allenes
TsOCH2CH@C@CR1R2 with [Mo(CO)3L3]ꢀ (L3 = Cp or
Tp) in Na dried THF [4,5]. However in a previous
publication, the author with others reported the formation
*
Corresponding author. Tel.: +44 117 32 82486; fax: +44 117 32 82904.
E-mail address: Annabelle.Hodson@uwe.ac.uk (A.G.W. Hodson).
0277-5387/$ - see front matter ꢁ 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2006.10.040

1286
A.G.W. Hodson et al. / Polyhedron 26 (2007) 1285–1291
2. Experimental
2.6. Synthesis of [MoCl(CO)2(g3-CH2C(COBr)-
C@CH2)(phen)]
2.1. Materials and physical methods
A suspension of 4a (365 mg, 0.5 mmol) and potassium
bromide (595 mg, 5.0 mmol) in refluxing acetone (50 ml)
was stirred for 18 h. The resulting mixture was poured into
water (20 ml), and then extracted twice with dichlorometh-
ane (25 ml). The separated organic layer was dried over
MgSO4, and removal of solvent in vacuo gave the
orange-red product. Yield = 45%.
The complexes [M(CO)4L2] and Ph4P[MCl(CO)3L2]
were freshly prepared by the published method [7], and
all other chemicals were purchased from commercial
sources and used without further purification. Experiments
were carried out under an N2 atmosphere. Infrared spectra
were recorded on a Perkin–Elmer 781 spectrometer using
samples prepared as nujol mulls on sodium chloride discs.
The 1H NMR spectra were obtained for solutions in
dimethylsulfoxide-d6 and were referenced to the solvent
as internal standard.
2.7. Synthesis of [MoCl(CO)2(g3-CH2C(COX)C@CH2)-
L2] (X = NHCH2CH@CH2, L2@bipy 6 or phen 7; X =
NC5H10, L2 = bipy 8; X = NHCH2C„CH, L2 = bipy 9)
2.2. Synthesis of [MoCl(CO)2(g3-CH2C(COCl)-
C@CH2)L2] (L2 = bipy 4a, L2 = phen 4b)
Method a: A mixture of [Mo(CO)4L2] (1.0 mmol) and
Ph4PCl (393 mg, 1.05 mmol) was stirred in CH2Cl2
(10 ml) with an excess of allyl amine, piperidine or propar-
gyl amine (0.25 ml), and to this was added 3 (0.1 ml). The
mixture darkened on addition, and after refluxing for 7 h,
the volume was reduced by half using a flow of N2. Storage
overnight at low temperature gave the product as orange-
red microcrystals. These were filtered from solution, and
recrystallized from methanol or CH2Cl2–petrol mixtures.
Method b: The acyl chloride complex was prepared as given
in Section 2.2, and to this was added the amine. After a fur-
ther 1 h reaction under reflux, the product was isolated as
described above. Method c: The reaction was carried out
as described in a, but [Mo(CO)4L2] and Ph4PCl were
replaced by Ph4P[MoCl(CO)3L2] (1.0 mmol). Yields of
each complex obtained by methods a–c were similar, and
in the range 42–68%.
A mixture of [Mo(CO)4L2] (2.0 mmol), Ph4PCl (824 mg,
2.2 mmol) and excess 1,4-dichloro-2-butyne (3) (0.2 ml)
was refluxed in CH2Cl2 (10 ml) for 6 h, cooled to room
temperature and then stored at 5 ꢀC for 3 days. The orange
product was filtered from solution and dried in vacuo.
Yields = 69% 4a, 73% 4b.
2.3. Synthesis of [WCl(CO)2(g3-CH2C(COCl)C@CH2)-
(2,9-Me2phen)] (4c)
A
mixture of [W(CO)4(2,9-Me2phen)] (504 mg,
1.0 mmol) and Ph4PCl (400 mg, 1.07 mmol) in 1,2-
C2H4Cl2 (25 ml) was refluxed for 6 h with an excess of 3
(0.1 ml). Reduction of the solvent volume under reduced
pressure followed by storage at 5 ꢀC for 3 days gave the
orange title product. This was filtered from solution and
dried in vacuo. Yield = 76%.
2.8. Synthesis of [WCl(CO)2(g3-CH2C(COX))C@CH2-
(2,9-Me2phen)] (X = N(CH2CH@CH2)2 10 or
NHCH(Ph)CO2Me 11)
2.4. Attempted preparation of 4a
The synthesis was carried out as described in Section 2.7
method a, but using 1,2-C2H4Cl2 and the appropriate
amine. Yields = 49% 10, 54% 11.
Mo(CO)6 (264 mg, 1.0 mmol), phen (180 mg, 1.0 mmol),
Ph4PCl (400 mg, 1.1 mmol) and 3 (0.1 ml) were refluxed in
CH2Cl2, CHCl3 or CH2Br2 (25 ml) and monitored by IR
spectroscopy for 3–72 h.
2.9. Synthesis of MoCl(CO)2(g3-CH2C(CO2CH2C„CH)-
C@CH2)(phen)] (12) and [MoCl(CO)2(g3-CH2C-
(COS(CH2)2SH)C@CH2)(phen)] (13)
2.5. Thermal study of 4a
Method a: Mixtures of [Mo(CO)4(phen)] (1a) (50 mg,
0.13 mmol) and Ph4PCl (60 mg, 0.16 mmol) were refluxed
with 3 (0.1 ml) in CH2Cl2, CHCl3, 1,1,1-C2H3Cl3, 1,2-
C2H4Cl2, CH2Br2 or C6H5Cl (25 ml) for 3–6 h. Method b:
The reaction was carried out as a, but 1a and Ph4PCl were
replaced by 4a (60 mg, 0.12 mmol). For both methods, the
complex [MoCl2(CO)(g2-ClCH2C„CCH2Cl)(phen)] (5)
was obtained from those solvents boiling in the range 61–
96 ꢀC. For 5: 1H NMR in DMSO-d6, 5.41 (brs, 4H),
8.05–9.35 (m, 8H); IR (Nujol) 1956 cmꢀ1; elemental Anal.
Calc. for (Æ0.5CH2Cl2): C, 38.85; H, 2.40; N 5.18. Found:
C, 39.70; H, 2.34; N 5.43.
The reaction was carried out as described in Section 2.7
method a, with the amine replaced by propargyl alcohol or
1,2-ethanedithiol (0.5 ml) and triethylamine (0.1 ml).
Yields = 54% 12, 47% 13.
2.10. X-ray crystallography
A single orange crystal of 9 (0.50 · 0.20 · 0.12 mm) was
grown from a CH2Cl2–petrol mixture and mounted on a
glass fibre in paratone oil. Data were collected at 120 K
on an Nonius KappaCCD area detector diffractometer
located at the window of a Nonius FR591 rotating anode

A.G.W. Hodson et al. / Polyhedron 26 (2007) 1285–1291
1287
X-ray generator, equipped with a molybdenum target (k
Mo Ka = 0.71073 A). The structure was solved and refined
Dc = 1.646 Mg/m3, l = 0.846 mmꢀ1
,
29518 measured,
˚
4422 unique (Rint = 0.0358) and 3827 (Fo > 4r(Fo)) reflec-
tions, R1 (obs) = 0.0287 and wR2 (all data) = 0.0732
using the SHELX-97 suite of programs and data were cor-
rected for absorption effects by means of comparison of
equivalent reflections using the program SADABS [8,9].
Non-hydrogen atoms were refined anisotropically, whilst
hydrogen atoms were fixed in idealised positions with their
thermal parameters riding on the values of their parent
atoms. Positional disorder (180ꢀ rotation) was found to
be present in the propargyl chain (C18–C20) with an occu-
pancy ratio of 66:34, and only one orientation of this chain
is shown in Fig. 1 for clarity. C20H16ClMoN3O3, mono-
ꢀ3
˚
q
max/qmin = 0.650/ꢀ0.933 e A
.
3. Results and discussion
3.1. Synthesis of substituted butadienyl complexes
A mixture of [Mo(CO)4L2] (L2 = phen, 1a, bipy 1b),
Ph4PCl and 1,4-dichloro-2-butyne (3) was refluxed in
CH2Cl2, and the product was monitored by IR and
NMR spectroscopy over time. After 3 h approximately
clinic, P21/c, a = 7.4910(1), b = 16.9292(3), c = 15.2343
3
˚
˚
(2) A, b = 93.9620(10)ꢀ, volume = 1927.35(5) A , Z = 4,
equal quantities of unreacted
1 and [MoCl(CO)2-
(g3-CH2C(COCl)C@CH2)L2] (4a,4b) were obtained, and
complete conversion of 1 to 4 was achieved after a further
3 h (Eq. (1), Scheme 1). During this period the orange reac-
tion mixture showed no signs of darkening due to forma-
tion of purple Ph4P[MoCl(CO)3L2] (2a,2b), nor was there
evidence of this compound in the spectra. This was not
unexpected, since 2 reacted rapidly with 3 at 20 ꢀC, and
at elevated temperatures would be consumed on formation.
Whilst yields of 4 were similar to the previous two stage
process (Eqs. (2) and (3)), the new reaction time exceeds
the latter by 3 h. A mixture of [W(CO)4(2,9-Me2phen)]
(1c), Ph4PCl and 3 heated in CH2Cl2, CHCl3 or 1,1,1-
C2H3Cl3 (40–72 ꢀC) over the same 6 h period showed no
spectroscopic change. However increasing the temperature
to 81 ꢀC (1,2-C2H4Cl2) afforded the acyl chloride (4c) in
good yield, and this new reaction time compares favour-
ably with the previous two stage total of 18 h (Eqs. (2)
and (3)). The practical and environmental advantages of
transferring to the one pot method are therefore, (i) isola-
tion of products in good yield using minimum glassware
and cleaning solvents, (ii) complete elimination of MeCN
(Eq. (2)), (iii) reduction of solvent temperatures by
60–70 ꢀC (previously 110 ꢀC Mo and 140 ꢀC W, Eq. (2))
Fig. 1. The crystal structure of [MoCl(CO)2(g3-CH2C(CONHCH2
C„CH)C@CH2)(2,20-bipyridine)] (9), with the second component of the
disordered propargyl chain (C180–C200) omitted for clarity.
M(CO)4L2 + Ph4PCl + ClCH2C≡CCH2Cl → [MCl(CO)2(η3-CH2C(COCl)C=CH2)L2]
(eqn. 1)
(eqn. 2)
(eqn. 3)
(eqn. 4)
1
3
4
→
1 + Ph4PCl
Ph4P[MCl(CO)3L2]
2
→
2 + 3
4
→
1 + Ph4PCl + 3
4 + 3 → 5
[MCl2(CO)(η2-ClCH2C≡CCH2Cl)L2]
5
(eqn. 5)
(eqn. 6)
1 + Ph4PCl + 3 + XH → [MCl(CO)2(η3-CH2C(COX)C=CH2)L2]
6-13
Scheme 1. Conditions: Eq. (1) D CH2Cl2 (Mo, 6 h) or 1,2-C2H4Cl2 (W, 6 h), Eq. (2) D toluene (Mo, 1 h) or xylene (W, 16 h) and MeCN, Eq. (3) RT
CH2Cl22 h, Eqs. 94) and (5) D CHCl36 h, Eq. (6) D CH2Cl2 (Mo, 7 h) or 1,2-C2H4Cl2 (W, 7 h).

1288
A.G.W. Hodson et al. / Polyhedron 26 (2007) 1285–1291
and (iv) reaction time for tungsten complexes reduced by
12 h.
Addition of primary or secondary amines XH to the one
pot reaction mixture of 1, Ph4PCl and 3 in CH2Cl2 afforded
substituted complexes of the type [MCl(CO)2-
(g3-CH2C(COX)C@CH2)L2] (6–11), and in the presence of
triethylamine and alcohol or thiol, the corresponding ester
and thioester complexes could also be achieved (X =
OCH2C„CH 12, S(CH2)2SH 13). These were character-
ized by their IR and NMR spectra (Tables 1 and 2), and
the stereochemistry of 9 was investigated by a single crystal
X-ray analysis. In some cases, where complexes were only
soluble in DMSO, reproducible elemental analyses could
not be obtained since oxidation to [Mo2Cl2O4(L2)2]
occurred readily on recrystallization [12]. Complete
replacement of CH2Cl2 by water in this one pot method
was not possible due to insolubility of 1. However 4 and
6–9 could be achieved from a two phase CH2Cl2/H2O sys-
tem, and where small volumes of the former were used,
water assisted mixing and filtration. For example, similar
yields of 4a and 6 were obtained when 10 ml CH2Cl2 was
replaced by 10 ml water and 0.5 ml CH2Cl2 in Sections
2.2 and 2.7, respectively. The tungsten complexes however
proved more sensitive to water, and on heating 1c, Ph4PCl
and 3 to 80 ꢀC in an equivolume mixture of 1,2-C2H4Cl2
and water (2.3), a mixture of 4c and the known complex
[WCl2(CO)3(2,9-Me2phen)] was obtained.
In an effort to decrease the time required to convert
[Mo(CO)4L2] to 4, reactions of 1a, Ph4PCl and 3 were car-
ried out in higher boiling point solvents. Coordinating sol-
vents were avoided in view of their potential reaction with 1
to form solvated compounds of the type [M(CO)3(L2)(S)]
[10], and chlorinated solvents were selected for their ability
to dissolve reactants and products. After 4 h in CHCl3
(61 ꢀC), peaks due to carbonyl stretching in 1a had been
replaced by those of 4a and an additional peak of almost
equal intensity at 1956 cmꢀ1. The latter predominated on
raising the temperature to 96 ꢀC (CH2Br2), and the com-
plex [MoCl2(CO)(g2-ClCH2C„CCH2Cl)(phen)] (5) was
isolated from solution. This product was also obtained
on refluxing a mixture of 4a and excess 1,4-dichloro-2-
butyne in this solvent (Eqs. (4) and (5), Scheme 1), and
one pot production of 5 occurred in solvents of higher boil-
ing point until onset of decomposition of intermediate 2
occurred at 129 ꢀC (C6H5Cl). Dichloroalkyne 3 is not
expected to undergo rearrangement within this temperature
range [11], and therefore the additional chlorine in 5 orig-
inates from decomposition of 4a. On refluxing 4a in
acetone containing bromide ions, the derivative [MoCl-
(CO)2(g3-CH2C(COBr)C@CH2)(phen)] was obtained,1
and thus both 4a and its acyl bromide analogue were stable
at 56 ꢀC. Isolation of 5 from one pot reactions of 1a,
Ph4PCl and 3 in solvents boiling within the range 61–
129 ꢀC was therefore attributable to destabilization at these
higher temperatures.
Attempts to prepare 4a or 4b by a one pot method using
[Mo(CO)6], L2, Ph4PCl and 3 in refluxing CH2Cl2 over sev-
eral days were less successful. Loss of CO from the hexa-
carbonyl was found to be slow at this temperature, and
12 h were required to form uncontaminated 1. The diimine
ligands bipy and phen, being weaker pi acceptors than CO,
labilize [M(CO)4L2] complexes towards dissociative ligand
loss from the position cis to them. This cis labilization
results in reaction substitution rates several orders of mag-
nitude larger for these chelate complexes than for
Mo(CO)6. After 24 h the IR solution spectrum showed car-
bonyl stretching absorptions due to 1 and acyl chloride
complex 4 of approximately equal intensity. However con-
tinued reaction times resulted in decreasing strength of
these bands, suggesting the acyl chloride was thermally
unstable over extended periods. A good yield of 4 could
not be obtained via this method after 48 h (21%), and little
remained in solution after refluxing for 72 h. Increasing the
reaction temperature by use of CHCl3 or CH2Br2 was
found to accelerate formation of 1 and 4, but also resulted
in more rapid decomposition of the latter.
3.2. Characterization of complexes
3.2.1. Spectroscopic data
All the g3-butadienyl complexes exhibited a pair of
strong absorptions in their IR spectra between 1982 and
1894 cmꢀ1 due to the metal cis-dicarbonyl fragment. A
band of medium intensity near 1710 cmꢀ1 arising from
m(C@O) of the acyl chloride 4 was shifted to lower wave-
number in 6–13, and weak peaks near 3400 or 3250 cmꢀ1
were assigned to m(NH) or m(C„CH), respectively. The
1H NMR spectra showed two singlets near 1.8 and
3.7 ppm due to the methylene terminus of the g3-bonded
butadienyl, and a pair of doublets arising from the double
bond of this unit appeared near 5.7 and 6.2 ppm, with cou-
pling constants of 2.2 Hz. Amide complexes containing
NH gave rise to a triplet between 6.1 and 6.6 ppm, and a
further triplet at 2.84 ppm was attributable to the terminal
propargyl proton of 9. Other signals due to aliphatic sub-
stituents of the butadienyl and aromatic protons of the
L2 ligand were unexceptional. As a result of their low sol-
ubilities, the 13C NMR spectra of 6–13 were not recorded.
3.2.2. Crystal structure determination of 9
A solid-state crystal structure determination of [MoCl-
(CO)2(g3-CH2C(CONHCH2C„CH)C@CH2)(2,20-bipyri-
dine)] was carried out to determine the stereochemistry of
the substituted g3-butadienyl fragment. Fig. 1 shows a view
of the molecule and the atomic labeling scheme used, and
selected bond lengths and angles for 9 are given in Table
3. The coordination geometry about the Mo centre may
be considered to be that of a slightly distorted octahedron
1
For [MoCl(CO)2(g3-CH2C(COBr)C@CH2)phen]: 1H NMR in
DMSO-d6 1.91 (s, H), 3.79 (s, H), 5.67 (d, 1.38H), 6.19 (d, 1.38H), 7.99
(m, 2H), 8.18 (s, 2H), 8.82 (m, 2H), 9.13 (d, 4.42H), 9.29 (d, 4.66H); IR
(Nujol), cmꢀ1. 1989, 1912, 1650.

A.G.W. Hodson et al. / Polyhedron 26 (2007) 1285–1291
1289
Table 1
Selected infrared and analytical data for [MCl(CO)2(g3-CH2C(COX)C@CH2)L2]g
No.
X
L2
Infrared dataa
Analysis, found (calculated) %
m(C„O)
m(C@O)
m(NH)
C
H
N
6
7
NHCH2CH@CH2
NHCH2CH@CH2
NC5H10
NHCH2C„CH
N(CH2CH@CH2)2
NHCH(Ph)CO2Me
OCH2C„CH
bipy
phen
bipy
bipy
Me2phen
Me2phen
phen
1958, 1881
1964, 1888
1960, 1890
1958, 1882
1980, 1896
1970, 1890
1973, 1897
1968, 1891
1639
1647
1609
1654
1628
1644, 1745
1701
3402
3429
50.10 (50.05)
3.47 (3.75)
8.65 (8.75)
e
8
51.38 (51.15)
50.20 (50.26)
4.64 (4.81)
3.31 (3.35)
e
7.63 (7.78)f
8.47 (8.79)
9b
10
11
12c
13d
a
3412
3408
47.81 (47.51)
46.37 (46.62)
3.54 (3.76)
e
5.46 (5.45)
5.55 (5.18)
SCH2CH2SH
phen
1637
2.84 (3.14)
As nujol mulls, cmꢀ1
m(C„CH) 3256 cmꢀ1
.
b
.
.
c
m(C„CH) 3249 cmꢀ1
d
e
f
m(SH) 2593 cmꢀ1
.
Non-reproducible results, highly insoluble or unstable.
Calc. MeOH.
M = Mo for all complexes, except 10, 11 where M = W.
g
Table 2
1H NMR data for complexes 6–13a
00
No.
H0anti
H0syn
H
H
NH
Aliphatic
Aromatic
anti
00
syn
6
1.79 (s, H),
3.70 (s, H)
5.63 (d, 2.2, H),
6.27 (d, 1.9, H)
6.30 (t, 5.5, H)
2.79 (m, H), 3.02 (m, H),
4.77 (m, 2H), 5.13 (m, H)
7.96 (m, 2H), 8.17 (m, 2H), 8.50 (m, 2H),
8.69 (d, 4.4, H), 8.81 (d, 4.9, H)
7
8
1.86 (s, H),
3.84 (s, H)
5.74 (d, 2.2, H),
6.29 (d, 2.2, H)
6.15 (t, 5.8, H)
6.58 (t, 5.5, H)
2.24 (m, H), 2.43 (m, H),
4.47 (m, 2H), 4.54 (m, H)
8.00 (m, 2H), 8.17 (s, 2H), 8.80 (m, 2H),
9.11 (d, 4.9, H), 9.24 (d, 4.9, H)
1.94 (s, H),
3.91 (s, H)
5.54 (d, 2.3, H),
6.09 (d, 2.4, H)
1.77 (m, 6H), 2.12 (m, H),
3.18 (m, H), 3.53 (m, 2H)
7.83 (m, 2H), 8.08 (m, 2H), 8.42 (m, 2H),
8.66 (m, H), 8.81 (m, H)
9
1.78 (s, H),
3.68 (s, H)
5.63 (d, 2.2, H),
6.25 (d, 2.5, H)
2.84 (t, 2.22H), 3.07 (m, 2H),
7.64 (m, 2H), 8.16 (m, 2H), 8.5 (m, 2H),
8.68 (d, 4.4, H), 8.81 (d, 4.7, H)
10
1.91 (s, H),
3.69 (s, H)
5.62 (d, 2.2, H),
6.16 (d, 2.2, H)
3.30 (s, 3H), 3.35 (s, 3H),
3.75 (d, 5.502H), 4.05 (d,
5.50,2H), 5.14 (m, 4H),
5.71 (m, 2H)
7.78 (m, 2H), 7.90 (s, 2H), 8.40 (m, 2H)
11
12
1.88 (s, H),
1.95 (s, H),
3.46 (s, H),
3.70 (s, H)
5.43 (d, 1.3, H),
5.49 (d, 1.5, H),
6.34 (d, 1.5, H),
6.48 (d, 1.5, H)
5.79 (d, 7.5, H),
6.37 (d, 6.4, H)
3.20 (s, 3H), 3.32 (s, 3H),
3.33 (s, 3H), 3.35 (s, 3H),
3.43 (s, 3H), 3.62 (s, H),
3.66 (s, 3H), 3.86 (brs, H)
6.85–7.15 (m, 10H), 7.65–7.89 (m, 10H),
8.33 (d, 2.4, H), 8.36 (d, 2.4, H)
1.97 (s, H),
3.74 (s, H)
5.71 (d, 2.2, H),
6.23 (d, 2.2, H)
2.96 (m, H), 3.13 (m, 2H)
2.16 (m, 2H), 2.34 (m, 2H)
8.04 (m, 2H), 8.20 (s, 2H), 8.84 (m, 2H),
9.14 (m, H), 9.33 (m, H)
13
1.93 (s, H),
3.85 (s, H)
5.78 (d, 2.2, H),
6.31 (d, 2.2, H)
8.09 (m, 2H), 8.19 (s, 2H), 8.82 (m, 2H),
9.12 (d, 4.9, H), 9.28 (d, 4.9, H)
a
Spectra recorded in DMSO-d6. Data reported in ppm, multiplicity, coupling constant (Hz), number of protons.
if the central atom of the butadienyl based ligand (C14) is
considered to be the point of attachment. The central
molybdenum atom is bonded to two carbonyl groups
[Mo1–C1 1.980(2) A; Mo1–C2 1.976(2) A], two nitrogens
of 2,20-bipyridine [Mo1–N1 2.2309(17) A; Mo1–N2
˚
C2–O2 178.5(2)ꢀ], and the C1–Mo1–C2 bond angle
[82.22(9)ꢀ], are all typical of a pair of mutually cis carbonyl
groups. The rings of the bipyridine unit are approximately
planar within experimental error, and their bond lengths
and angles are similar to values found for related molybde-
num g3-allyl and g3-pentadienyl bipyridyl complexes
[13–15].
˚
˚
˚
˚
2.2246(16) A], a chlorine atom [Mo1–Cl1 2.4997(5) A]
and a 2-substituted butadienyl unit, C8H8NO. The metal–
˚
CO and carbonyl bond lengths [C1–O1 1.150(3) A; C2–
O2 1.147(3) A] and angles [Mo1–C1–O1 179.3(2)ꢀ; Mo1–
Within the butadienyl moiety, the C13–C14–C15 angle
of 113.27(19)ꢀ, the C13–C14 and C14–C15 bond lengths
˚

1290
A.G.W. Hodson et al. / Polyhedron 26 (2007) 1285–1291
Table 3
arrangement of L2Y at the metal has been found in solu-
3
˚
Selected bond lengths (A) and angles (ꢀ) for [MoCl(CO)2(g -CH2C-
(CONHCH2C„CH)C@CH2)(bipy)] (9)
tion and solid states for bipy and phen complexes
[Mo(CO)2(g3-RC3H4)L2Y] (R = H, 1-Me) [13,16]. In con-
trast, solid state structures of 9 and its phen thioester
(M = W, X = SBu) and selenoester (M = Mo, X = SePh)
analogues all exhibit a symmetrical arrangement of the
M(CO)2L2Cl unit [20,21] and their NMR solution spectra
are non-complex and invariant over the temperature range
ꢀ50 to 20 ꢀC. Whilst allyl complexes [W(CO)2-
Mo1–C1
Mo1–C2
Mo1–N1
Mo1–N2
Mo1–Cl1
C14–C17
C17–O3
C17–N3
N3–C18
1.980(2)
1.976(2)
2.2309(17)
2.2246(16)
2.4997(5)
1.495(3)
1.226(3)
1.346(3)
1.456(4)
Mo1–C13
Mo1–C14
Mo1–C15
C13–C14
C14–C15
C15–C16
C1–O1
C2–O2
C18–C19
C19–C20
2.300(9)
2.228(8)
2.208(9)
1.423(3)
1.414(3)
1.317(3)
1.150(3)
1.147(3)
1.458(6)
1.180(4)
(g3-CH2CRCH2)L3]+
(L3 = bis(2-methylpyridyl)amine)
exhibit dynamic behaviour in solution at room temperature
for both R = H and Me, and an asymmetric arrangement
of the tridentate ligand has been shown in the solid state
[22], fluxionality has not been reported for either
[Mo(CO)2(g3-CH2CHC@CH2)Cp] or [Mo(CO)2(g3-CH2-
CMeC@CH2)Tp] [4,5]. A more detailed molecular orbital
description of bonding in metal g3-butadienyl complexes
is required to explain these differences.
C1–Mo1–C2
N1–Mo1–N2
O1–C1–Mo1
C14–C17–O3
C17–N3–C18
C14–Mo1–N1
C2–Mo1–C15
C2–Mo1–N2
C15–Mo1–N2
C1–Mo1–C14
N2–Mo1–C14
C1–Mo1–N1
C2–Mo1–C13
C15–Mo1–C13
C14–Mo1–C13
C2–Mo1–Cl1
C15–Mo1–C11
C14–Mo1–C11
C13–Mo1–C11
82.22(9)
73.37(6)
179.3(2)
121.2(2)
117.9(2)
87.25(7)
69.71(8)
165.93(8)
121.85(7)
102.18(8)
88.99(7)
168.27(7)
107.51(9)
63.39(8)
36.52(8)
85.62(6)
147.29(5)
167.36(5)
147.83(6)
C13–C14–C15
C14–C15–C16
O2–C2–Mo1
O3–C17–N3
113.27(19)
141.6(2)
178.5(2)
122.9(2)
110.8(4)
178.9(4)
109.90(8)
99.56(8)
104.34(8)
37.26(7)
102.37(8)
81.83(7)
66.94(9)
85.84(7)
120.77(7)
86.67(6)
80.58(4)
82.96(4)
N3–C18–C19
C18–C19–C20
C1–Mo1–C15
C1–Mo1–N2
C2–Mo1–C14
C15–Mo1–C14
C2–Mo1–N1
C15–Mo1–N1
C1–Mo1–C13
N2–Mo1–C13
N1–Mo1–C13
C1–Mo1–C11
N2–Mo1–C11
N1–Mo1–C11
4. Conclusions
Complexes containing the g3-CH2C(COCl)C@CH2
moiety can be synthesized from 1,4-dichloro-2-butyne by
a one pot reaction with [M(CO)4L2] and Ph4PCl. Chlori-
nated solvents with boiling points in the range 40–60 ꢀC
(M = Mo) or 83–96 ꢀC (M = W) are required for this con-
version, and at elevated temperatures destabilization of the
butadienyl complex can occur to afford [MCl2(CO)-
(g2-ClCH2C„CCH2Cl)L2]. Preparation of the g3-dienyl
complex from one pot reactions involving [M(CO)6] are
hindered by this temperature requirement. Loss of CO
below 60 ꢀC (Mo) or 96 ꢀC (W) is relatively slow and rate
determining, and over the necessarily extended periods,
increasing decomposition of dienyl product occurs. In con-
trast, conversion of the tetracarbonyl to [MCl(CO)3L2]ꢀ
occurs more rapidly, and reaction in situ with the dic-
hloroalkyne is fast. Thus under conditions for successful
one pot production of the acyl chloride, addition of alco-
hols, amines or thiols generates the analogous ester, amide
and thioester complexes, and in general these are found to
have greater thermal stability below 120 ꢀC. Both Mo and
W complexes can also be obtained in the presence of water,
however for the latter, formation of [WCl2(CO)3L2] as a
co-product reduces final yields. Comparison of the struc-
ture of propargyl amide 9 with related selenoester and thi-
˚
of 1.423(3) and 1.414(3) A respectively, and the Mo1–C13
˚
and Mo1–C14 separations of 2.300(9) and 2.228(8) A are
all similar to 1- and 2-substituted g3-allyl complexes of
molybdenum [16–18]. However the shorter Mo1–C15 dis-
˚
tance of 2.208(9) A may reflect an intermediate bond order
between 1 and 2 that is not expected within an g3-allyl sys-
tem. (Compare [Mo(CO)2(g3-1-RC3H4)(phen)(O2CCF3)]
˚
˚
R = H 2.316(5) A, R = Me 2.411(13) A.) Although the
C15–C16 bond length of 1.317(3) A is slightly longer than
that observed for the related selenoester 2-substituted com-
plex [1.242(13) A], this value is consistent with related
˚
˚
dienyl complexes of the type [Mo(CO)2(g3-CH2CHC@
CR1R2)L3] (L3 = Cp, Tp; R1, R2 = H, Me) [4,5,19]. A
non-planar arrangement of hydrogen atoms at terminal
atoms C13 and C16 suggests the double bond C15–C16 is
not conjugated with respect to the C13–C14–C15 unit,
and this should be reflected in the chemical reactivity.
The amide group of the butadienyl fragment is approxi-
mately planar, with the carbonyl orientated away from
the C@CH2 terminus, and the propargyl substituent
extends over the bipy ring system. The C18–C19–C20 angle
oester reveals
a common arrangement of the acyl
substituent and non-coordinated double bond. Isomers of
these forms have not been observed in solution or solid
states, and a combination of steric and electrostatic factors
may explain the preferred orientation. Crystallographic
data of all three complexes suggest pi-delocalization within
the metal bound C1C2C3 unit is unconjugated with respect
to C3@C4, and whilst these complexes may undergo simi-
lar reactions to substituted g3-allyl analogues, the unusu-
ally short M–C3 bond length suggests direct parallels
can’t be assumed. Their behaviour with nucleophilic and
electrophilic reagents is under investigation.
˚
of 178.9(4)ꢀ and the C19–C20 bond length of 1.180(6) A
are both in accord with this linear chain.
Asymmetry at the metal centre may occur in related
complexes of the type [Mo(CO)2(g3-allyl)L2Y] due to a
non-dissociative trigonal twist rearrangement of L2Y
against the M(CO)2(allyl) unit, and this may give rise to
dynamic NMR spectra. For example, an asymmetric

A.G.W. Hodson et al. / Polyhedron 26 (2007) 1285–1291
1291
[6] A.G.W. Hodson, R.K. Thind, O. Granville-George, J. Organomet.
Chem. 689 (2004) 2114.
Appendix A. Supplementary material
[7] B.J. Brisdon, D.A. Edwards, J.W. White, J. Organomet. Chem. 156
(1978) 427.
[8] G.M. Sheldrick, SHELX-97: Programs for Structure Solution and
Refinement, University of Go¨ttingen, Germany, 1997.
[9] G.M. Sheldrick, SADABS, Version 2.10, Bruker AXS Inc., Madison,
WI, USA, 2003.
[10] L.W. Houk, G.R. Dobson, Inorg. Chem. 5 (1966) 2119.
[11] A.G.W. Hodson, J. Organomet. Chem. 691 (2006) 4747.
[12] (a) H.K. Saha, M.C. Halder, J. Inorg. Nucl. Chem. 34 (1972)
3097;
(b) P.C.H. Mitchell, J. Inorg. Nucl. Chem. 25 (1963) 963.
[13] J.R. Ascenso, C.G. de Azevedo, M.J. Calhorda, M.A.A.F. de C.T.
Carrondo, P. Costa, A.R. Dias, M.G.B. Drew, V. Felix, A.M.
CCDC 612555 contains the supplementary crystallo-
graphic data for the crystal structure reported in this paper.
These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or
e-mail: deposit@ccdc.cam.ac.uk. Supplementary data asso-
ciated with this article can be found, in the online version,
at doi:10.1016/j.poly.2006.10.040.
References
Galvao, C.C. Romao, J. Organomet. Chem. 632 (2001) 197.
˜
˜
[14] S. Lush, S. Wang, G. Lee, S. Peng, S. Wang, R. Liu, Organometallics
9 (1990) 1862.
[1] (a) O. Boutry, M.L. Poveda, E. Carmona, J. Organomet. Chem. 528
(1997) 143;
[15] M.D. Curtis, N.A. Fotinos, J. Organomet. Chem. 272 (1984)
43.
(b) C.P. Casey, S. Chung, Y. Ha, D.R. Powell, Inorg. Chim. Acta 265
(1997) 127.
[16] L. Eriksson, M.P.T. Sjogren, B. Akermark, Acta Crystallogr. C 52
(1996) 77.
[17] P. Powell, J. Organomet. Chem. 129 (1977) 175.
[18] C. Borgmann, C. Limberg, E. Kaifer, H. Pritzkov, L. Zsolnai, J.
Organomet. Chem. 580 (1999) 214.
[2] (a) M. Ogasawara, H. Ikeda, T. Hayashi, Angew. Chem., Int. Ed. 39
(2000) 1042;
(b) M. Ogasawara, H. Ikeda, T. Nagano, T. Hayashi, Org. Lett. 3
(2001) 2615;
(c) M. Ogasawara, H. Ikeda, T. Nagano, T. Hayashi, J. Am. Chem.
Soc. 123 (2001) 2089.
[3] S. Kezuka, K. Kanemoto, R. Takeuchi, Tetrahedron Lett. 45 (2004)
6403.
[19] S.A. Benyunes, R.J. Deeth, A. Fries, M. Green, M. McPartlin,
C.B.M. Nation, J. Chem. Soc., Dalton Trans. (1992) 3453.
[20] A.G.W. Hodson, R.K. Thind, M. McPartlin, J. Organomet. Chem.
664 (2002) 277.
[4] N. Vinson, C.S. Day, M.E. Welker, Organometallics 19 (2000) 4356.
[5] D.R. Lantero, A.G. Glenn, C.S. Day, M.E. Welker, Organometallics
22 (2003) 1998.
[21] A.G.W. Hodson, G. Conole, Organometallics 17 (1998) 5347.
[22] B.J. Brisdon, M. Cartwright, A.G.W. Hodson, M.F. Mahon, K.C.
Molloy, J. Organomet. Chem. 435 (1992) 319.