Cis- and trans-bis(diphenylphosphino)ethene seven-coordinate complexes of molybdenum(II) and tungsten(II). Crystal structures of [MI2(CO)3(cis-dppen)] {M=Mo or W; Dppen=bis(diphenylphosphino)ethene}, [WI(CO)2(cis-dppen)<su

Article abstract of DOI:10.1016/S0022-328X(00)00136-4

Equimolar quantities of [MI₂(CO)₃(NCMe)₂] (M=Mo or W) and cis-dppen {dppen=Ph₂PCH=CHPPh₂} react in CH₂Cl₂ at room temperature to give good yields of the crystallographically char

Full text of DOI:10.1016/S0022-328X(00)00136-4

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Journal of Organometallic Chemistry 602 (2000) 115–124
Cis- and trans-bis(diphenylphosphino)ethene seven-coordinate
complexes of molybdenum(II) and tungsten(II). Crystal structures
of [MI2(CO)3(cis-dppen)] {M=Mo or W;
dppen=bis(diphenylphosphino)ethene}, [WI(CO)2(cis-dppen)2]I,
[MI2(CO)2{P(OR)3}(cis-dppen)] (M=Mo, R=Me; M=W,
R=Et or Ph)
Paul K. Baker a,*, Michael G.B. Drew b, Archie W. Johans b, Latifah Abdol Latif a,c
a Department of Chemistry, Uni6ersity of Wales, Bangor, Gwynedd LL57 2UW, UK
b Department of Chemistry, Uni6ersity of Reading, Whiteknights, Reading RG6 6AD, UK
c Centre for Foundation Studies in Science, Uni6ersity of Malaya, 50603 Kuala Lumpur, Malaysia
Received 29 December 1999; received in revised form 13 February 2000
Abstract
Equimolar quantities of [MI2(CO)3(NCMe)2] (M=Mo or W) and cis-dppen {dppen=Ph2PCHꢀCHPPh2} react in CH2Cl2 at
room temperature to give good yields of the crystallographically characterised complexes [MI2(CO)3(cis-dppen)] (1 and 2).
Treatment of [WI2(CO)3(NCMe)2] with two equivalents of cis-dppen affords the crystallographically characterised cationic
complex [WI(CO)2(cis-dppen)2]I (3). Reaction of [MI2(CO)3(NCMe)2] with one equivalent of cis-dppen, followed by addition of
an equimolar amount of P(OR)3 affords the mixed ligand complexes [MI2(CO)2{P(OR)3}(cis-dppen)] (M=Mo or W; R=Me, Et,
n
iPr, Bu or Ph) (4–13). The X-ray crystal structures for M=Mo, R=Me; M=W, R=Et or Ph are also determined. Treatment
of equimolar quantities of [MoI2(CO)3(NCMe)2] and P(OiPr)3 gave [MoI2(CO)3(NCMe){P(OiPr)3}], which reacted in situ with
half an equivalent of trans-dppen to furnish the bimetallic phosphine-bridged complex [{MoI2(CO)3{P(OiPr)3}}2(m-trans-dppen)]
(14). © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Cis- and trans-bis(diphenylphosphino)ethene; Seven-coordinate; Molybdenum(II); Tungsten(II); Crystal structures
1. Introduction
no examples containing the rotationally restricted phos-
phines cis- and trans-dppen (dppen=Ph2PCHꢀ
CHPPh2) have been described. While there are numer-
ous crystal structures containing the ligands dppe and
dppm with a wide range of metals, much less attention
has been given to the unsaturated ligands such as
dppen. Indeed we found no crystal structures in the
Cambridge Crystallographic Database containing this
ligand with molybdenum or tungsten apart from the
octahedral structures [Mo(CO)4(cis-dppen)] [24],
[Mo(CO)2(cis-dppen)2] [24] and [Mo(CO)2(dppe)(cis-
dppen)] [25]. There has, however, been considerable
interest in the analogous diarsenic bidentate ligand L2,
{L2=cis-2,3-bis(dimethylarsino-1,1,1,4,4,4,-hexafluoro-
but-2-ene} and the structures of [WI2(CO)2{P(OMe)3}-
Since the first halocarbonyl donor ligand complex
[MoI2(CO)2(diars)] was reported by Nigam and Ny-
holm in 1957 [1], much effort has been put into investi-
gating the synthesis [2–5], structures [6,7] and catalytic
activity [8,9] of seven-coordinate complexes of the type
[MX2(CO)3L2]. Although a large number of seven-coor-
dinate halocarbonyl complexes of molybdenum(II) and
tungsten(II) containing mono-, bi- and tridentate phos-
phine ligands have been reported [2–5,10–23], hitherto,
* Corresponding author. Fax: +44-1248-370528.
E-mail address: chs018@bangor.ac.uk (P.K. Baker)
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 0 ) 0 0 1 3 6 - 4

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P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
Table 1
Physical and analytical data for cis- and trans-bis(diphenylphosphino)ethene complexes of molybdenum(II) and tungsten(II)
Complex
Colour
Yield (%)
Analysis (%) {Found (Calc.)}
C
H
[MoI2(CO)3(cis-dppen)] (1)
[WI2(CO)3(cis-dppen)] (2)
[WI(CO)2(cis-dppen)2]I (3)
Reddish orange
Yellow
Yellow
Yellow orange
Yellow
Yellow orange
Yellow
Yellow orange
Yellow
Orange
Yellow orange
Orange
Orange
59
73
80
48
53
73
70
54
68
61
77
49
83
66
41.5 (41.8)
38.2 (37.9)
47.5 (48.2)
39.1 (40.2)
39.4 (36.9)
41.8 (42.1)
38.3 (38.7)
43.8 (44.0)
41.0 (40.5)
45.3 (45.5)
42.4 (42.1)
49.4 (49.6)
44.0 (43.9)
35.5 (35.6)
2.7 (2.7)
2.5 (2.4)
3.4 (3.4)
3.4 (3.4)
2.7 (2.5)
3.8 (3.8)
3.5 (3.5)
4.4 (4.3)
3.8 (4.0)
4.4 (4.7)
4.4 (4.3)
3.7 (3.4)
3.1 (3.1)
4.0 (3.8)
[MoI2(CO)2{P(OMe)3}(cis-dppen)] (4)
[WI2(CO)2{P(OMe)3}(cis-dppen)] (5)
[MoI2(CO)2{P(OEt)3}(cis-dppen)] (6)
[WI2(CO)2{P(OEt)3}(cis-dppen)] (7)
[MoI2(CO)2{P(OiPr)3}(cis-dppen)] (8)
[WI2(CO)2{P(OiPr)3}(cis-dppen)] (9)
[MoI2(CO)2{P(OnBu)3}(cis-dppen)] (10)
[WI2(CO)2{P(OnBu)3}(cis-dppen)] (11)
[MoI2(CO)2{P(OPh)3}(cis-dppen)] (12)
[WI2(CO)2{P(OPh)3}(cis-dppen)]·CH2Cl2 (13)
[{MoI2(CO)3{P(OiPr)3}}2(m-trans-dppen)] (14)
Off-white
(L2)] [26], [WI2(CO)3L2] [27] and [WBr2(CO){P(OMe)3} 2-
L2] [28] are all relevant to the structures reported here.
In the first two structures the metal atoms have a
distorted capped trigonal prism environment, but in the
diphosphite, the metal has a distorted capped octa-
hedral environment.
In 1986 [29], we described the synthesis of the highly
versatile seven-coordinate complexes [MI2(CO)3-
(NCMe)2] (M=Mo or W). These complexes are pre-
pared by reacting the zero-valent complexes fac-
[M(CO)3(NCMe)3] (prepared in situ) [30] with an
equimolar amount of I2 at 0°C. In this paper, we
describe the reactions of [MI2(CO)3(NCMe)2] and their
phosphite derivatives with cis- and trans-dppen. The
molecular structures of [MI2(CO)3(cis-dppen)] {M=
Mo or W; dppen=bis(diphenylphosphino)ethene},
lography. They are both moderately soluble in CH2Cl2,
CHCl3, but insoluble in hydrocarbon solvents and di-
ethyl ether. They are stable in the solid state when
stored under dinitrogen, but decompose rapidly when
exposed to air in solution. The IR spectra of 1 and 2
show three carbonyl bands, which suggests there is one
isomer in solution. This was confirmed by the 1H-NMR
spectra (Table 3), and the 31P-NMR spectrum of 1,
which showed a single resonance at l=54.8 ppm which
suggests the complex is fluxional at room temperature.
Suitable single crystals of 1 for X-ray crystallography
were grown by cooling (−17°C) a concentrated solu-
tion of [MoI2(CO)3(cis-dppen)] (1) in CDCl3 in an
NMR tube for 2 weeks. Suitable single crystals of the
tungsten complex [WI2(CO)3(cis-dppen)] (2) were ob-
tained by cooling (−17°C) a concentrated CH2Cl2
[WI(CO)2(cis-dppen)2]I,
[MI2(CO)2{P(OR)3}(cis-
dppen)] (M=Mo, R=Me; M=W, R=Et or Ph) are
also discussed.
Table 2
IR data a for the cis- and trans-dppen complexes of molybdenum(II)
and tungsten(II)
Complex
w(CO) (cm−1
)
2. Results and discussion
1
2
3
2066 s; 1979 s; 1928 s
2022 s; 1967 s; 1918 s
1933 s; 1866 s
2.1. Synthesis and crystal structures of
[MI2(CO)3(cis-dppen)] (1 and 2)
4
1955 s; 1872 s
5
6
1946 s; 1866 m
1951 s; 1878 s
Reaction of equimolar quantities of [MI2(CO)3-
(NCMe)2] (M=Mo or W) and cis-dppen in CH2Cl2 at
room temperature gave the acetonitrile displaced prod-
ucts [MI2(CO)3(cis-dppen)] (1 and 2) probably via a
dissociative mechanism, since the bis(acetonitrile) com-
plexes obey the effective atomic number rule. Com-
plexes 1 and 2 have been characterised by elemental
analysis (C, H and N) (Table 1), IR and 1H-NMR
spectroscopy (Tables 2 and 3), in selected cases by
31P-NMR spectroscopy (Table 4), and by X-ray crystal-
7
8
9
10
11
12
13
14
1944 s; 1864 s
1953 s; 1876 s
1940 s; 1861 s
1951 s; 1880 s
1932 s; 1830 s
1958 s; 1880 s
1948 s; 1866 s
2030 m; 1972 s; 1938 s
a Recorded as thin CHCl3 films between NaCl plates. m, medium;
s, strong.

P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
117
Table 3
,
bonds to P(3) are ca. 0.09 A shorter than bonds to P(6),
no doubt because of lengthening in the latter case due
to the trans-effect of the carbonyl ligand. This geome-
try is typical of structures of the type [WI2(CO)3(LꢁL)]
(M=Mo, W; LꢁL=bidentate ligand) and can be com-
pared, in particular, with structures containing dppe
e.g. [MoBr2(CO)3(dppe)] [31], [WI2(CO)3(dppe)] [32],
and [MoI2(CO)3(dppe)] [33].
Proton NMR data a for the cis- and trans-dppen complexes of
molybdenum(II) and tungsten(II)
Complex
l (ppm)/J (Hz)
1
2
7.8–7.3 (m, 20H, Ph2PCHꢀCHPPh2); 3.95 (s, 2H,
Ph2CHꢀCHPPh2)
7.8–7.2 (m, 20H, Ph2PCHꢀCHPPh2); 3.9 (br, s, 2H,
Ph2PCHꢀCHPPh2)
3
4
7.6–6.9 (m, 40H, Ph); 4.0 (s, 4H, Ph2PCHꢀCHPPh2)
7.9–7.3 (br, m, 20H, Ph); 4.0 (s, 2H,
Ph2PCHꢀCHPPh2); 3.75 {d, 9H, P(OCH3)3}
7.9–7.2 (br, m, 20H, Ph); 4.0 (br, 2H,
Ph2PCHꢀCHPPh2); 3.7 {d, 9H, P(OCH3)3}
7.9–7.3 (br, m, 20H, Ph); 4.2 {qt, 6H,
P(OCH2CH3)3}; 3.9 (br, 2H, Ph2PCHꢀCHPPh2);
1.3 {t, 9H, P(OCH2CH3)3}
7.9–7.2 (br, m, 20H, Ph); 4.15 {qt, 6H,
P(OCH2CH3)3}; 4.0 (br, 2H, Ph2PCHꢀCHPPh2);
1.4 {t, 9H, P(OCH2CH3)3}
7.9–7.0 (br, m, 20H, Ph); 4.35 (br, 3H,
P{OCHꢁ(CH3)2}3); 3.6 (s, 2H, Ph2PCHꢀCHPPh2);
1.28 (d, 18H, P{OCH(CH3)2}3)
8.0–7.0 (br, m, 20H, Ph); 4.86 (br, 3H,
P{OCH(CH3)2}3); 4.2 (br, 2H, Ph2PCHꢀCHPPh2);
1.3 (d, 18H, P{OCH(CH3)2}3)
8.0–7.1 (br, m, 20H, Ph); 4.12 {br, qt, 6H,
P(OCH2ꢁCH2CH2CH3)3, +2H, Ph2PCHꢀCHPPh2};
1.65 {m, 6H, P(OCH2CH2CH2CH3)3}; 1.4 {m, 6H,
P(OCH2CH2CH2CH3)3}; 0.95 {t, 9H,
P(OCH2CH2CH2CH3)3}
8.1–6.9 (br, m, 20H, Ph); 4.1 {br, m, 6H,
P(OCH2CH2CH2CH3)3+2H, PhPCHꢀCHPPh2};
1.68 {m, 6H, P(OCH2CH2CH2CH3)3}; 1.45 {m, 6H,
P(OCH2CH2CH2CH3)3}; 0.95 {t, 9H,
P(OCH2CH2CH2CH3)3}
7.6–6.8 (br, m, 35H, Ph); 5.3 (s, 2H, CH2Cl2);
3.7 (br, s, Ph2PCHꢀCHPPh2)
2.2. Synthesis and crystal structure of
[WI(CO)2(cisdppen)2]I (3)
5
6
Reaction of [WI2(CO)3(NCMe)2] with two equiva-
lents of cis-dppen in CH2Cl2 at room temperature gave
the cationic complex [WI(CO)2(cis-dppen)2]I (3) in 80%
yield. The complex was fully characterised in the nor-
mal manner (see Tables 1–4). Complex 3 is slightly
more soluble in chlorinated solvents, and is more stable
to oxidation than 1 and 2. The infrared spectrum shows
two carbonyl bands at 1933 and 1866 cm−1, which
suggests the carbonyl groups are cis- to each other and
this is confirmed by the X-ray crystal structure (Fig. 3).
The 31P-NMR spectrum (CDCl3, 25°C) shows a single
resonance at l=37.8, Jwp=160.5 Hz, which intimates
the four phosphorus atoms are in the same environ-
ment and suggests the complex is fluxional at room
temperature (Fig. 3).
7
8
9
10
11
Suitable single crystals for X-ray analysis were grown
by cooling a concentrated CH2Cl2 solution of 3 to
−17°C, to which had been added a few drops of
diethyl ether. The structure for 3 is shown in Fig. 3,
13
14
7.75–7.3 (br, m, 20H, Ph); 4.8 (br, m, 6H,
P{OCH(CH3)2}3); 3.7 (s, 2H, Ph2PCHꢀCHPPh2);
1.5 {d, 36H, P{OCH(CH3)2}3}
Table 4
31P{1H}-NMR data a for selected cis- and trans-dppen complexes of
molybdenum(II) and tungsten(II)
a Spectra recorded in CDCl3 at 25°C, referenced to SiMe4. s,
singlet; m, multiplet; d, doublet; qt, quintet; t, triplet; br, broad.
Complex
l (ppm)/J (Hz)
1
3
4
54.8 (s, cis-dppen)
37.8 (s, JWꢁP=160.5 Hz, cis-dppen)
solution of 2 to which a few drops of diethyl ether had
been added.
131.9 {dd, (br-cis, 1P, JPꢁP=215 Hz-trans)-
P(OMe)3}; 73.8 {s, br-cis-dppen); 37.5 {dd,
(br-cis, JPꢁP=215 Hz-trans)cis-dppen}
105.2 {dd, (br-cis, JPꢁP=210 Hz-trans)-P(OMe)3};
55.5 {s, br-cis-dppen, JWꢁP=206 Hz}; 23.0 {dd,
(br-cis-, JPꢁP=210 Hz-trans)cis-dppen}
128.5 {dd, (2JPꢁP=23 Hz-cis-dppen, JPꢁP=203 Hz-
trans)P(OEt)3}; 73.9 {s, br-cis-dppen, JWꢁP=228
Hz}; 36.2 {dd, (JPꢁP=23 Hz-cis-dppen, JPꢁP=203
Hz-trans)cis-dppen}
97.2 {dd, (br-cis, JPꢁP=185 Hz-trans)-P(OEt)3}; 52.6
{s, br, -cis-dppen, JWꢁP=180 Hz}; 20.2 {dd, (br-cis,
1P, JPꢁP=185 Hz-trans)cis-dppen}
The molecular structures of 1 and 2 are shown in
Figs. 1 and 2, together with their common atom num-
bering schemes. The structures of 1 and 2 are equiva-
lent with the metal atom bonded to three carbonyl
atoms, two iodine atoms and the bidentate cis-dppen
ligand. The geometry of the metal coordination sphere
can best be considered as a distorted capped octahe-
dron with C(200) in the capping position, the other two
carbonyls in the capped face together with one of the
phosphorus atoms P(3) from the bidentate dppen lig-
and. The other phosphorus atom P(4) from this ligand,
together with the two iodine atoms make up the un-
capped face. The dimensions in the two structures are
as expected and almost equivalent reflecting the similar
radii of Mo and W. It is particularly noticeable that the
5
6
7
13
82.9 {dd, (2JPꢁP=27 Hz-cis, JPꢁP=231 Hz-trans),
P(OPh)3}; 33.9 {t, br, -cis-dppen}; 21.5 {dd,
(2JPꢁP=27 Hz-cis, JPꢁP=231 Hz-trans)cis-dppen}
155.85 {br, s, P(OiPr)3}; 12.15 (br, s, trans-dppen)
14
a Spectra recorded in CDCl3 at 25°C and referenced to 85% H3PO4.
dd, doublet of doublets; s, singlet; br, broad; t, triplet.

118
P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
Fig. 1. ORTEP representation of 1, together with the atom numbering scheme. Ellipsoids shown at 30% probability.
Fig. 2. ORTEP representation of 2, together with the atom numbering scheme. Ellipsoids shown at 30% probability.
,
together with the atomic numbering scheme. Although
the data for this complex are poor, they are of suffi-
cient quality to show the basic geometry of the com-
plex. In 3 the metal atom is seven-coordinate being
bonded to two bidentate cis-dppen ligands, named A
and B, two carbonyls and an iodine atom. The metal
geometry is best considered as a capped octahedron,
with C(100) in the capping position, C(200), two
phosphorus atoms from different ligands P(3A) and
P(3B) in the capped face while P(6A), P(6B) and the
iodine atom occupy the uncapped face. The carbonyl
in the capped face C(200) is trans to the iodine in the
uncapped face. The bond lengths to the two phospho-
rus atoms in the capped face are significantly shorter
at 2.513(6), 2.543(7)A than the bonds to the phospho-
,
rus atoms in the uncapped face at 2.605(6), 2.629(7)A.
There have been several structure determinations con-
taining the stoichiometry [MX(CO)2(PꢁP)2]+, (M=
Mo, W; X=halogen; LꢁL=bidentate phosphorus
ligand), and the majority of these have the capped
trigonal prismatic structure with the halogen in the
capping position, four phosphorus atoms in the
capped face and two carbonyls in the remaining edge,
e.g. for example [WI(CO)2(dppe)2]I [34]. It is not clear
why 3 has the capped octahedral structure but it
could be due to the relative inflexibility of the unsatu-
rated dppen ligand which necessarily forms a closely
planar chelate ring.

P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
119
Fig. 3. ORTEP representation of 3, together with the atom numbering scheme. Ellipsoids shown at 30% probability.
2.3. Synthesis and selecti6e crystal structures of
[MI2(CO)2{P(OR)3}(cis-dppen)] (4–13)
Suitable single crystals for X-ray analysis of
[MI2(CO)2{P(OR)3}(cis-dppen)] (M=Mo, R=Me;
M=W, R=Et or Ph) (4, 7 and 13) were grown by
cooling (−17°C) CH2Cl2:Et2O (80:20) concentrated so-
lutions of 4, 7 and 13, respectively. The structures of 4,
7 and 13 are shown in Figs. 4–6, together with their
atomic numbering schemes. In 4, 7 and 13, the metal
atom is also seven-coordinate, but this time the com-
plex is neutral with the metal bonded to two iodide
Treatment of [MI2(CO)3(NCMe)2] with an equimolar
amount of cis-dppen in CH2Cl2 at room temperature
gave [MI2(CO)3(cis-dppen)], which react in situ with
one equivalent of P(OR)3 to eventually give the mixed-
ligand seven-coordinate complexes [MI2(CO)2{P-
i
(OR)3}(cis-dppen)] (M=Mo or W; R=Me, Et, Pr,
nBu or Ph) (4–13) in good yield. Complexes 4–13 have
all been fully characterised (see Tables 1–4). The com-
plex [WI2(CO)2{P(OPh)3}(cis-dppen)]·CH2Cl2 (13) was
confirmed as a CH2Cl2 solvate by repeated elemental
1
analysis and H-NMR spectroscopy. Complexes 4–13
are all considerably more soluble than 1–3, which is
almost certainly due to the solubilising properties of the
phosphite ligands. Their stability is similar to com-
plexes 1–3.
The IR spectra of 4–13 all show, as expected, two
carbonyl bands which suggests cis-carbonyls. The room
temperature 31P-NMR spectra (Table 4) of 4, 5, 6, 7
and 13 all have three resonances for the three different
phosphorus atoms which suggests the complexes are
not fluxional at room temperature on the NMR
timescale. For example, complex 13 has resonances at
l=82.9 ppm and is a doublet of doublets due to the
P(OPh)3 coupling with both the approximately cis- and
trans-phosphorus atoms of the cis-dppen ligand. The
resonance at l=33.9 ppm is an unresolved triplet due
to a coupling of the P(OPh)3 and phosphorus on the
dppen ligand which are approximately trans- to each
other (see Fig. 6). The other phosphorus resonance at
l=21.5 ppm is as expected a doublet of doublets.
Fig. 4. ORTEP representation of 4, together with the atom numbering
scheme. Ellipsoids shown at 30% probability.

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P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
Fig. 5. ORTEP representation of 7, together with the atom numbering scheme. Ellipsoids shown at 30% probability.
Fig. 6. ORTEP representation of 13, together with the atom numbering scheme. Ellipsoids shown at 30% probability.
of the form [MI2(CO)2{P(OR)3}(LꢁL)] (M=Mo, W,
R=Me, Et, Pr, Ph; LꢁL=dppm or dppe). The struc-
tures of 4, 7 and 13 are all very similar and, indeed,
atoms, two carbonyls, a bidentate cis-dppen ligand and
a monodentate phosphite ligand. In a recent paper [35],
we have described nine crystal structures of complexes
i

P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
121
some are isomorphous (see Section 3) to those with the
dppe ligand, with the metal atom in a capped octa-
hedral environment, with a carbonyl in the capping posi-
tion, one carbonyl, one phosphorus from the phosphite
ligand and one from the bidentate ligand in the capped
face and the other phosphorus from the bidentate
ligand, and two iodide ligands in the uncapped face.
These three structures (4, 7 and 13) show no signifi-
cant structural changes as a consequence of containing
the unsaturated bidentate cis-dppen ligand. One feature
of these structures, and the nine described previously
[35], is that neither the change of metal, nor the identity
of the alkyl group R in the phosphite has any system-
atic difference on the stereochemistry around the metal
atom.
identical environments to each other. It seems that the
most likely structure for the bimetallic complex 14 is
the bridged structure shown in Fig. 7.
2.5. Conclusions
We have shown that our highly versatile seven-coor-
dinate complexes [MI2(CO)3(NCMe)2] (M=Mo or W)
can react with cis- and trans-dppen to give a wide range
of the first examples of cis- and trans-Ph2PCHꢀ
CHPPh2 seven-coordinate complexes, six of which have
been structurally characterised. The structures of the
seven-coordinate complexes have been compared and
show a wide range of types depending on the types of
ligand attached to the metal.
The six structures, all of which contain the unsatu-
rated bidentate dppen ligand, are shown in Figs. 1–6,
respectively, together with the common numbering
schemes. The envelope conformation of the five-mem-
bered bidentate ring is found in all structures but there
are various degrees of fold. Thus deviations of the two
carbon atoms from the M (M=Mo, W), P(3), P(6)
plane are in (1) 0.40, 0.34, (2) 0.33, 0.30, (3) 0.58, 0.36;
0.85, 0.80, (4) 0.43, 0.50, (7) 0.36, 0.33; 0.37, 0.23, (13)
2.4. Synthesis of [{MoI2(CO)3{P(OiPr)3}}2-
(v-trans-dppen)] (14)
Reaction of [MoI2(CO)3(NCMe)2] with an equimolar
amount of P(OiPr)3 in CH2Cl2 at room temperature
gives [MoI2(CO)3(NCMe){P(OiPr)3}], which reacts in
situ with half an equivalent of trans-Ph2PCHꢀCHPPh2
to eventually give the phosphine-bridged bimetallic
complex [{MoI2(CO)3{P(OiPr)3}}2(trans-dppen)] (14).
Complex 14 was characterised in the normal manner
(see Tables 1–4), and has similar stability and solubility
to complexes 4–13.
,
0.41, 0.49 A. This contrasts with the dppe bidentate
ligand in which the two carbon atoms are on opposite
sides of the M, P, P plane.
The IR spectrum of complex 14, has three carbonyl
bands, which suggests that each metal centre, as ex-
pected, has an identical arrangement of ligands. This is
confirmed by the 31P-NMR spectrum (CDCl3, 25°C) of
14, which has two resonances at l=155.85 and 12.15
ppm. The low field resonance (155.85) for the equiva-
lent triisopropylphosphite ligands, and a higher field
resonance (12.15) for the equivalent trans-
Ph2PCHꢀCHPPh2 phosphorus atoms. Several unsuc-
cessful attempts were made to grow suitable single
crystals for X-ray analysis of 14. However, we have
recently described the preparation and X-ray crystal
structure [36] of the closely related complex [{MoI2-
(CO)3{P(OiPr)3}}2(m-dppb)] {dppb=Ph2P(CH2)4PPh2},
which indeed shows that the molybdenum centres are in
3. Experimental
All reactions and work-up procedures described in
this paper were carried out under an atmosphere of dry
nitrogen using conventional vacuum line and Schlenk
tube techniques. The solvents used CH2Cl2 and Et2O
were dried and distilled before use. The starting materi-
als used, [MI2(CO)3(NCMe)2] (M=Mo and W) were
prepared by the published procedure [29]. The phosph-
ines, cis- and trans-Ph2PCHꢀCHPPh2 and other chemi-
cals were purchased from commercial sources.
Elemental analyses (C, H and N) were determined
using a Carlo Erba Elemental Analyser MOD 1108
(using helium as the carrier gas). IR spectra were
recorded on a Perkin–Elmer 1600 FTIR spectrophoto-
1
meter. H- and 31P-NMR spectra were recorded on a
Bruker AC 250 MHz NMR spectrometer. 1H-NMR
spectra were referenced to SiMe4, and 31P-NMR spectra
were referenced to 85% H3PO4.
3.1. Syntheses
3.1.1. Syntheses of [MI2(CO)3(cis-dppen)] (1 and 2)
To a stirred solution of [MoI2(CO)3(NCMe)2] (0.500
g, 0.969 mmol) in CH2Cl2 (50 cm3) was added cis-
dppen (0.384 g, 0.969 mmol). The colour changed from
dark brown to orange–red. Filtration and removal of
Fig. 7. Proposed structure of [{MoI2(CO)3{P(OiPr)3}}2(m-trans-dp-
pen)] (14).

122
P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
Table 5
Crystal data and structure refinement details for structures 1–4, 7 and 13
1
2
3
4
7
13
Formula
MoI2(CO)3-
(dppen)
WI2(CO)3-
(dppen)
[WI(CO)2-
(dppen)2]ICH2Cl2 (P(OMe)3)·EtOH
MoI2(CO)2(dppen)- WI2(CO)2-
WI2(CO)2-
(dppen)(P(OEt)3) (dppen)(P(OPh)3)
C34H35I2MoO5P3 C46H39I2O5P3W
Empirical formula
C29H22I2MoO3P2 C29H22I2WO3P2 C55H46Cl2I2O2P4W C33H37I2MoO6P3
Formula weight (g)
Crystal system
Spacegroup
799.19
Orthorhombic
Pbca
975.01
Orthorhombic
Pbca
1371.35
Monoclinic
P21/c
972.27
Monoclinic
C2/c
1054.18
Monoclinic
P21/a
1202.33
Monoclinic
P21/c
Unit cell dimensions
,
a (A)
16.91(2)
16.454(18)
21.26(2)
90
90
90
5915(12)
8
1.795
2.028
16.91(2)
16.404(18)
21.22(2)
90
90
90
5887(12)
8
2.200
8.895
10.608(12)
12.891(14)
43.16(5)
90
96.30(1)
90
5866(11)
4
1.553
36.73(4)
10.729(12)
19.99(2)
90
113.04(1)
90
7249(14)
8
1.782
10.292(8)
18.998(14)
21.37(3)
69.92(1)
89.63(1)
75.54(1)
3765(6)
4
16.270(17)
14.411(16)
21.42(2)
90
106.51(1)
90
4814(9)
4
1.659
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
Volume (A )
Z
Dcalc (g cm−3
)
1.860
4.872
Absorption coefficient
(mm−1
F(000)
3.258
2.239
3.822
)
3096
3608
2664
3664
2016
2320
Crystal size (mm)
q Range for data
collection (°)
0.25×0.25×0.20 0.20×0.17×0.15 0.25×0.25×0.15 0.20×0.15×0.15
0.25×0.20×0.20 0.25×0.25×0.25
2.65–25.92
2.92–26.01
2.24–26.13
2.16–26.02
2.61–25.96
2.33–26.05
Index ranges
−205h520
05k518
255l525
−115h514
05k519
−185l520
9655
05h511
05h545
−95k59
−245l522
6927
05h512
−215k523
−265l526
12202
−175h515
05k516
−245l524
10266
−145k514
−535l552
13734
No. reflections collected 19316
No. unique reflections 5409 (0.0386)
(Rint
3714 (0.0688)
8291 (0.0356)
4553 (0.0373)
12202
5654 (0.1033)
)
Data/restraints/paramete 5409/0/335
3714/144/335
8291/0/263
4553/0/396
12202/0/817
5654/36/420
rs
Final R indices
[I\2|(I)]
R1
wR2
0.0798
0.2324
0.1009
0.2857
0.1255
0.3450
0.0663
0.2072
0.0903
0.2113
0.1050
0.2491
R Indices (all data)
R1
0.0940
0.1234
0.1383
0.1020
0.1374
0.2125
wR2
0.2485
0.3131
0.3508
0.2313
0.2378
0.3032
Extinction coefficient
0.0008(3)
0.00000(13)
4.384, −2.339
0.0026(13)
3.264, −2.178
0.00035(3)
1.414, −0.848
0.00015(11)
2.284, −1.613
0.0000(2)
3.666, −1.705
Largest difference peak 4.606, −2.121
−3
,
and hole (e A
)
most of the solvent in vacuo after 24 h yielded analyti-
cally pure orange–red crystals of [MoI2(CO)3(cis-
dppen)] (1) (0.477 g, 59%). Single crystals of
[MoI2(CO)3(dppen)] (1), suitable for X-ray crystallogra-
phy were obtained from the NMR sample (in CDCl3).
The tungsten analogue [WI2(CO)3(cis-dppen)] (2) was
prepared in an exactly analogous manner to complex 1
above. However, suitable single crystals for X-ray anal-
ysis were grown by adding a few drops of Et2O to a
concentrated CH2Cl2 solution of [WI2(CO)3(cis-dppen)]
(2), and cooling in the fridge (−17°C) for 1 week. See
Table 1 for physical and analytical data.
(1.05 g, 2.65 mmol) with continuous stirring under a
stream of dry N2 for 24 h. Filtration and removal of
most of the solvent in vacuo yielded a yellow solid. The
complex was recrystallised by redissolving in CH2Cl2,
concentrating the solution and adding a few drops of
Et2O to give, after cooling at −17°C for 1 week,
suitable single crystals for X-ray analysis of
[WI(CO)2(cis-dppen)2]I (3) (yield of pure product=
0.94 g, 80%).
3.1.3. [MI2(CO)2{P(OR)3}(cis-dppen)] (M=Mo, W;
i
n
R=Me, Et, Pr, Bu and Ph)
typical example: to
A
a solution of [MoI2-
3.1.2. [WI(CO)2(cis-dppen)2]I (3)
(CO)3(NCMe)2] (0.500 g, 0.969 mmol) in CH2Cl2 (50
cm3) was added cis-dppen (0.384 g, 0.969 mmol) with
stirring under a stream of dry N2. An immediate colour
To a stirred solution of [WI2(CO)3(NCMe)2] (0.800 g,
1.325 mmol) in CH2Cl2 (50 cm3) was added cis-dppen

P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
123
Table 6
Molecular dimensions (distances (A) and angles (°)) for structures 1, 2, 4, 7 and 13
,
1 (M=Mo)
2 (M=W)
4 (M=Mo) 7 (M=W)
13 (M=W)
a
b
Bond lengths
M(1)ꢁC(100)
M(1)ꢁC(200)
M(1)ꢁC(300)
M(1)ꢁP(6)
M(1)ꢁP(3)
M(1)ꢁI(2)
Bond lengths
M(1)ꢁC(100)
M(1)ꢁC(200)
M(1)ꢁP(7)
M(1)ꢁP(6)
M(1)ꢁP(3)
M(1)ꢁI(2)
1.984(10)
1.966(11)
2.082(14)
2.608(3)
2.509(3)
2.846(3)
2.882(2)
2.01(3)
1.87(3)
2.00(2)
2.593(6)
2.510(5)
2.848(4)
2.879(3)
1.941(13)
2.004(19)
2.488(4)
2.492(4)
2.599(4)
2.879(3)
2.916(3)
1.96(2)
2.00(2)
1.952(18)
2.00(2)
1.84(2)
1.89(3)
2.510(6)
2.480(6)
2.614(5)
2.868(2)
2.910(3)
2.501(6)
2.475(6)
2.593(5)
2.895(3)
2.905(3)
2.471(8)
2.516(6)
2.603(7)
2.883(4)
2.861(4)
M(1)ꢁI(3)
M(1)ꢁI(3)
Bond angles
Bond angles
C(100)ꢁM(1)ꢁC(200)
C(200)ꢁM(1)ꢁC(300)
C(100)ꢁM(1)ꢁC(300)
C(300)ꢁM(1)ꢁP(6)
C(200)ꢁM(1)ꢁP(6)
C(100)ꢁM(1)ꢁP(6)
C(300)ꢁM(1)ꢁP(3)
C(200)ꢁM(1)ꢁP(3)
C(100)ꢁM(1)ꢁP(3)
P(6)ꢁM(1)ꢁP(3)
C(100)ꢁM(1)ꢁI(2)
C(200)ꢁM(1)ꢁI(2)
C(300)ꢁM(1)ꢁI(2)
P(3)ꢁM(1)ꢁI(2)
72.6(5)
72.7(5)
109.3(5)
158.7(4)
128.4(3)
83.1(4)
113.0(4)
72.7(3)
112.2(4)
75.9(1)
159.3(4)
127.7(4)
77.4(4)
81.2(1)
85.2(1)
75.1(4)
124.8(3)
77.6(5)
162.4(1)
89.6(1)
87.9(1)
74.0(11)
73.8(10)
107.4(10)
157.7(8)
128.3(8)
83.7(6)
115.2(9)
70.9(7)
112.3(7)
76.0(7)
159.5(7)
126.2(8)
78.4(7)
81.2(1)
84.9(2)
75.7(7)
127.4(7)
75.8(9)
161.6(1)
88.9(1)
87.1(1)
C(100)ꢁM(1)ꢁC(200)
C(100)ꢁM(1)ꢁP(7)
C(200)ꢁM(1)ꢁP(7)
C(100)ꢁM(1)ꢁP(6)
C(200)ꢁM(1)ꢁP(6)
P(7)ꢁM(1)ꢁP(6)
C(100)ꢁM(1)ꢁP(3)
C(200)ꢁM(1)ꢁP(3)
P(7)ꢁM(1)ꢁP(3)
P(6)ꢁM(1)ꢁP(3)
C(100)ꢁM(1)ꢁI(2)
C(200)ꢁM(1)ꢁI(2)
P(7)ꢁM(1)ꢁI(2)
P(6)ꢁM(1)ꢁI(2)
P(3)ꢁM(1)ꢁI(2)
C(100)ꢁM(1)ꢁI(3)
C(200)ꢁM(1)ꢁI(3)
P(7)ꢁM(1)ꢁI(3)
P(6)ꢁM(1)ꢁI(3)
P(3)ꢁM(1)ꢁI(3)
I(2)ꢁM(1)ꢁI(3)
71.1(5)
73.2(5)
110.7(4)
71.7(4)
108.6(4)
113.4(1)
128.8(5)
83.5(4)
157.8(1)
75.8(1)
125.7(4)
163.0(3)
79.5(1)
78.0(1)
83.1(1)
125.0(3)
75.6(4)
79.4(1)
162.5(1)
88.1(1)
93.6(1)
71.7(9)
75.2(6)
108.3(6)
71.1(5)
108.4(7)
117.8(2)
128.0(6)
82.5(5)
156.8(1)
75.7(2)
125.4(6)
162.7(6)
81.2(1)
78.1(1)
83.7(1)
126.3(5)
74.4(7)
77.4(1)
161.0(1)
86.2(1)
94.2(1)
71.4(7)
73.9(6)
107.5(7)
71.5(6)
108.7(5)
117.2(2)
129.4(6)
84.1(5)
157.0(2)
75.9(2)
124.7(5)
163.7(5)
77.9(1)
77.6(1)
82.9(1)
126.3(5)
74.9(3)
77.9(1)
160.9(1)
86.1(1)
94.3(8)
72.8(11)
73.6(6)
102.6(9)
70.7(3)
108.2(8)
122.3(2)
131.1(6)
86.2(9)
155.2(2)
75.2(2)
119.6(7)
167.4(8)
80.5(2)
86.3(2)
79.6(2)
133.5(3)
78.9(8)
77.6(2)
154.9(2)
81.5(3)
90.0(1)
P(6)ꢁM(1)ꢁI(2)
C(100)ꢁM(1)ꢁI(3)
C(200)ꢁM(1)ꢁI(3)
C(300)ꢁM(1)ꢁI(3)
P(3)ꢁM(1)ꢁI(3)
P(6)ꢁM(1)ꢁI(3)
I(2)ꢁM(1)ꢁI(3)
change from dark brown to yellowish brown was ob-
served. After stirring for 20 min, P(OEt)3 (0.161 g,
0.969 mmol) was added. Filtration and removal of
solvent in vacuo after 1 h yielded a yellow solid, which
was recrystallised from CH2Cl2:Et2O (80:20) to afford
analytically pure crystals of [MoI2(CO)2{P(OEt)3}(cis-
dppen)] (6) (yield=0.686 g, 73%).
Celite, the solvent reduced in vacuo to half its volume,
and a few drops of Et2O was added. After cooling the
CH2Cl2:Et2O (80:20) mixture to −17°C for 72 h, an
analytically pure off-white powder of [{MoI2(CO)3{P-
(OiPr)3}}2(m-trans-dppen)] (14) (yield=0.540 g, 66%)
was isolated.
The other molybdenum complexes were prepared in
an exactly analogous manner. For the W complexes, a
similar procedure was followed, but the mixture was
stirred for 3 h, after addition of the P(OR)3 ligand,
instead of for 1 h as in the Mo complexes. See Table 1
for physical and analytical data for complexes 4–13.
3.1.5. Crystallography — crystal structure
determinations
Crystal data for the six compounds are given in
Table 5 together with refinement details. Molecular
dimensions are given in Table 6. For all compounds,
data were collected with Mo–Ka radiation using the
MarResearch Image Plate System. The crystals were
positioned at 70 mm from the Image Plate. A total of
95 frames were positioned at 2° intervals with a default
counting time of 2 min. However, frames for com-
pounds 3 and 4 were measured for 5 and 15 min,
respectively. Compounds 1 and 2 were isomorphous.
3.1.4. [{MoI2(CO)3(P(OiPr)3)}2(v-trans-dppen)] (14)
To a solution of [MoI2(CO)3(NCMe)2] (0.500 g, 0.969
mmol) dissolved in CH2Cl2 (30 cm3) at room tempera-
ture, under a stream of dry N2, was added P(OiPr)3
(0.202 g, 0.969 mmol). The mixture was stirred for 1
min, after which trans-dppen (0.192 g, 0.484 mmol) was
added and the solution was stirred for a further 3 h.
The resulting brown solution was filtered through
Complex
4 was isomorphous with [WI2(CO)2{P-
(OEt)3}(dppe)] [35], but with an ethanol solvent
molecule disordered over two overlapping sites, and 7

124
P.K. Baker et al. / Journal of Organometallic Chemistry 602 (2000) 115–124
[3] R. Colton, Coord. Chem. Rev. 6 (1971) 269 and Refs. cited
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[4] P.K. Baker, Adv. Organomet. Chem. 40 (1996) 45 and Refs.
cited therein.
[5] P.K. Baker, Chem. Soc. Rev. 27 (1998) 125 and Refs. cited
therein.
[6] M.G.B. Drew, Prog. Inorg. Chem. 23 (1977) 67 and Refs. cited
therein.
[7] M. Meln´ık, P. Sharrock, Coord. Chem. Rev. 65 (1985) 49 and
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9.
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[14] P. Umland, H. Vahrenkamp, Chem. Ber. 115 (1982) 3555.
[15] F.A. Cotton, R. Poli, Inorg. Chem. 25 (1986) 3703.
[16] P.K. Baker, S.G. Fraser, Inorg. Chim. Acta 116 (1986) L1.
[17] P.K. Baker, S.G. Fraser, Inorg. Chim. Acta 130 (1987) 61.
[18] P.K. Baker, S.G. Fraser, M.G.B. Drew, J. Chem. Soc. Dalton
Trans. (1988) 2729.
with [MoI2(CO)2{P(OEt)3}(dppm)] [35]. Data analyses
were carried out with the XDS program [37]. The struc-
tures were solved using direct methods with the SHELXL
program [38].
In the majority of structures (1, 2, 4, 7 and 13) all
non-hydrogen atoms were refined with anisotropic ther-
mal parameters. In 3, only the W, I and P atoms were
refined anisotropically and two of the phenyl rings were
constrained at calculated geometry. In 13, the phenyl
rings were refined anisotropically, but with thermal
parameters constrained to be compatible with those of
atoms in the same rings. All structures were corrected
for absorption using empirical methods [39]. The struc-
tures were then refined on F2 using SHELXL [40]. All
calculations were carried out on a Silicon Graphics
R4000 Workstation at the University of Reading.
4. Supplementary material
[19] P.K. Baker, D.J.T. Sharp, J. Coord. Chem. 16 (1988) 389.
[20] P.K. Baker, E.M. Armstrong, Polyhedron 9 (1990) 801.
[21] P.K. Baker, M.A. Beckett, L.M. Severs, J. Organomet. Chem.
409 (1991) 213.
[22] P.K. Baker, D.J. Sherlock, Polyhedron 13 (1994) 525.
[23] S.C.N. Hsu, W.-H. Yeh, M.Y. Chaing, J. Organomet. Chem.
492 (1995) 121.
[24] C.-H. Ueng, L.-C. Leu, Acta Crystallogr. Sect. C 47 (1991) 725.
[25] C.-H. Ueng, R.-S. Lee, J. Chin. Chem. Soc. 38 (1991) 155.
[26] L.M. Mihichuk, C.L. Giesingeer, B.E. Robertson, R.J. Barton,
Can. J. Chem. 65 (1987) 2634.
[27] A. Merier, J. Trotter, Can. J. Chem. 52 (1974) 3331.
[28] L. Mihichuk, M. Pizzey, B. Robertson, R. Burton, Can. J.
Chem. 64 (1986) 991.
For complexes 1–4, 7 and 13, tables of remaining
molecular dimensions not included in the paper, an-
isotropic and isotropic thermal parameters, and hydro-
gen coordinates are available. The data have been
lodged with the Cambridge Crystallographic Database,
CCDC nos. 135506 to 135511 inclusive. Copies of this
information may be obtained free of charge from: The
Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK (fax: +44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
[29] P.K. Baker, S.G. Fraser, E.M. Keys, J. Organomet. Chem. 309
(1986) 319.
Acknowledgements
[30] D.P. Tate, W.R. Knipple, J.M. Augl, Inorg. Chem. 1 (1962) 433.
[31] M.G.B. Drew, J. Chem. Soc. Dalton Trans. (1972) 1329.
[32] M.G.B. Drew, C.J. Rix, J. Organomet. Chem. 102 (1975) 467.
[33] R.M. Foy, D.L. Kepert, C.L. Raston, A.H. White, J. Chem.
Soc. Dalton Trans. (1980) 440.
[34] M.G.B. Drew, A.P. Wolters, Acta Crystallogr. Sect. B 33 (1977)
1977.
[35] P.K. Baker, M.G.B. Drew, U. Haas, L.A. Latif, M.M. Meehan,
J. Organomet. Chem. 590 (1999) 77.
L.A.L. thanks the British Council for providing her
with a Research Attachment Award (British Chevening
Award) and the University of Malaya for other finan-
cial support and leave. We thank the EPSRC and the
University of Reading for funds for the Image Plate
System.
[36] P.K. Baker, L.A. Latif, M.M. Meehan, S. Zanin, M.G.B. Drew,
Polyhedron 18 (1998) 257.
References
[37] W. Kabsch, J. Appl. Cryst. 21 (1988) 916.
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[39] N. Walker, D. Stuart, Acta Crystallogr. Sect. A 39 (1983) 158.
[40] G.M. Sheldrick, SHELXL, Program for Crystal Structure Refine-
ment, University of Go¨ttingen, Germany, 1993.
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