3-Hexyne complexes of molybdenum(II) and tungsten(II) containing phosphite ligands: X-ray crystal structures of [MoI2(CO)(NCMe){P(OPh)3}(η2-EtC 2Et)], [MoI2(CO)(dppe)(η2-EtC2Et)] and [MI2(CO){P(OiPr)3}2(η 2-EtC2Et)] (M=Mo and W)

Article abstract of DOI:10.1016/S0022-328X(00)00926-8

Equimolar quantities of [MoI₂(CO)(NCMe)(η²-EtC₂Et)₂] and P(OR)₃ (R=Ph, ⁱPr) gave the 3-hexyne displaced products, [MoI₂(CO)(NCMe){P(OR)₃}(η²-EtC ₂Et)] (1) and (2), which was crystallographically characterised for R=Ph. By contrast, reaction of equimolar quantities of [WI₂(CO)(NCMe)(η²-EtC₂Et)₂] and P(OR)₃ (R=Me, ⁱPr, Ph) afforded the acetonitrile displaced products, [WI₂(CO){P(OR)₃}(η²-EtC₂Et) ₂] (3 to 5). The reactions of the mono(triphenylphosphite)molybdenum complex, [MoI₂(CO)(NCMe){P(OPh)₃}(η²-EtC ₂Et)] (1) with a series of neutral mono, bidentate and anionic dithiocarbamate ligands have been investigated to give a variety of reaction products, including [MoI₂(CO)(dppe)(η²-EtC₂Et)] (12), which has been structurally characterised. Reaction of [MI₂(CO)(NCMe)(η²-EtC₂Et)₂] with two equivalents of P(OR)₃ gave the mono(3-hexyne) complexes, [MI₂(CO){P(OR)₃}₂(η²-EtC ₂Et)] {M=Mo or W; R=Me, Et, ⁱPr, ⁿBu, Ph(for M=W only)} (15 to 23), which were crystallographically characterised for M=Mo and W, R=ⁱPr 19 and 20, respectively.

Full text of DOI:10.1016/S0022-328X(00)00926-8

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 622 (2001) 228–241
3-Hexyne complexes of molybdenum(II) and tungsten(II)
containing phosphite ligands: X-ray crystal structures of
[MoI2(CO)(NCMe){P(OPh)3}(h2-EtC2Et)],
[MoI2(CO)(dppe)(h2-EtC2Et)] and [MI2(CO){P(OiPr)3}2(h2-EtC2Et)]
(M=Mo and W)
Mutlaq Al-Jahdali a, Paul K. Baker a,*, Michael G.B. Drew b
a Department of Chemistry, Uni6ersity of Wales, Bangor, Gwynedd, LL57 2UW, UK
b Department of Chemistry, Uni6ersity of Reading, Whiteknights, Reading, RG6 6AD, UK
Received 7 August 2000; received in revised form 27 November 2000; accepted 27 November 2000
Abstract
i
Equimolar quantities of [MoI2(CO)(NCMe)(h2-EtC2Et)2] and P(OR)3 (R=Ph, Pr) gave the 3-hexyne displaced products,
[MoI2(CO)(NCMe){P(OR)3}(h2-EtC2Et)] (1) and (2), which was crystallographically characterised for R=Ph. By contrast,
i
reaction of equimolar quantities of [WI2(CO)(NCMe)(h2-EtC2Et)2] and P(OR)3 (R=Me, Pr, Ph) afforded the acetonitrile
displaced products, [WI2(CO){P(OR)3}(h2-EtC2Et)2] (3 to 5). The reactions of the mono(triphenylphosphite)molybdenum
complex, [MoI2(CO)(NCMe){P(OPh)3}(h2-EtC2Et)] (1) with a series of neutral mono, bidentate and anionic dithiocarbamate
ligands have been investigated to give a variety of reaction products, including [MoI2(CO)(dppe)(h2-EtC2Et)] (12), which has been
structurally characterised. Reaction of [MI2(CO)(NCMe)(h2-EtC2Et)2] with two equivalents of P(OR)3 gave the mono(3-hexyne)
i
n
complexes, [MI2(CO){P(OR)3}2(h2-EtC2Et)] {M=Mo or W; R=Me, Et, Pr, Bu, Ph(for M=W only)} (15 to 23), which were
crystallographically characterised for M=Mo and W, R=iPr 19 and 20, respectively. © 2001 Elsevier Science B.V. All rights
reserved.
Keywords: 3-Hexyne; Phosphites; Molybdenum(II); Tungsten(II); Diiodo; Carbonyl; Crystal structures
1. Introduction
in 1982 [3].
In 1999 [30], we described the preparation of the
[MI2(CO)(NCMe)(h2-
Halocarbonyl alkyne complexes of molybdenum(II)
and tungsten(II) have received considerable attention
over the years, and two extensive review articles have
been published on this area [1,2]. Although many halo-
carbonyl alkyne complexes containing two phosphine
or phosphite ligands of the type [MXY(CO)L2(h2-
RC2R%)] (M=Mo, W; X=Cl, Br, I; R% ,R%=alkyl, aryl
etc) have been described [3–30], few examples contain-
ing one phosphine or phosphite ligand have been re-
ported. Some early examples are the mono(ligand)
bis(3-hexyne)
complexes
EtC2Et)2] (M=Mo or W), and their reactions with
phosphine donor ligands to give a series of bis(phos-
phine) complexes, including the crystallographically
characterised complexes, [WI2(CO)(PPh3)2(h2-EtC2Et)]
and [WI2(CO){Ph2P(CH2)3PPh2}(h2-EtC2Et)]. In 1989
[31], we reported the preparation of the bis(phosphite)
complexes [WI2(CO){P(OR)3}2(h2-R%C2R%)] (R=Me,
i
n
Et, Pr and Bu; R%=Me or Ph), which was structurally
characterised for R=R%=Me. Very recently [32], we
have described the synthesis and crystallographic char-
acterisation of the first mono(phosphite) complexes of
the type [MoI2(CO)(NCMe){P(OPh)3}(h2-R%C2R%%)]
(R%=R%%=Me or Ph; R%=Me, R%%=Ph), and also
extended the series of bis(phosphite) complexes
complexes,
[WI2(CO)2L(h2-HC2But)]
(L=CNtBu,
PMe3, AsMe3) described by Umland and Vahrenkamp
* Corresponding author. Fax: +44-1248-370528.
E-mail address: chs018@bangor.ac.uk (P.K. Baker).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00926-8

M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
229
[MI2(CO){P(OR)3}2h2-R%C2R%%)], including six which
were crystallographically characterised. In this paper,
we describe the synthesis and structural characterisation
lowers the bond order and hence the alkyne stretching
frequency.
A suitable single crystal of the triphenylphosphite
complex, [MoI2(CO)(NCMe){P(OPh)3}(h2-EtC2Et)] (1)
was grown by cooling (−17°C) a concentrated diethyl
ether solution of 1 for 24 h. The structure of 1 is shown
in Fig. 1. The crystal data and structure refinement for
1 are given in Table 6 and bond lengths and angles are
given in Table 7. The metal environment is best consid-
ered as a distorted octahedron with the hexyne moiety
occupying one site. The molybdenum atom is bonded
(R=Ph)
for
the
mono(3-hexyne)
complexes
[MoI2(CO)(NCMe){P(OR)3}(h2-EtC2Et)] (R=iPr, Ph).
We also describe the chemistry of the structurally char-
acterised complex [MoI2(CO(NCMe){P(OPh)3}(h2-
EtC2Et)], to give a variety of products including the
crystallographically
characterised
product,
[MoI2(CO)(dppe)(h2-EtC2Et)]. The new 3-hexyne bis
(phosphite) complexes [MI2(CO){P(OR)3}2(h2-EtC2Et)]
(M=Mo, W; R=Me, Et, Pr, Bu , Ph (for M=W
only)}, including M=Mo or W, R=iPr, which were
structurally characterised are also discussed.
i
n
,
to a carbonyl group {Mo(1)ꢀC(200), 1.948(14) A},
,
trans to an acetonitrile {Mo(1)ꢀN(300), 2.212(13) A},
,
and a phosphite ligand {Mo(1)ꢀP(4), 2.485(4) A}, trans
,
to an iodide {MoꢀI(2), 2.799(3) A}. The coordination
sphere is completed by the hexyne Mo(1)ꢀC(5)
,
2. Results and discussion
2.007(12), Mo(1)ꢀC(4) 2.040(13) A, trans to iodide {I(3)
,
at 2.862(3) A}. The bond from the iodide trans to
2.1. The synthesis and X-ray crystal structure (R=Ph)
of [MoI2(CO)(NCMe)(P(OR)3}(p2-EtC2Et)] (R=Ph or
iPr) (1) and (2)
phosphite is significantly shorter than the bond from
the iodide trans to the hexyne, presumably because the
latter bond is weakened by the trans effect.
It is probable that the reaction of the complexes
[MI2(CO)(NCMe)(h2-EtC2Et)2] (M=Mo or W) with
P(OR)3 proceed via an associative mechanism, as the
3-hexyne ligand can change its bonding mode from
being a 4-electron to a 2-electron donor, upon addition
of P(OR)3. This type of associative mechanism has been
previously described for this type of substitution reac-
tion in molybdenum(II) and tungsten(II) alkyne com-
plexes [33,34]. The 31P{1H}-NMR (CDCl3, +25°C)
spectrum of 1 has a single resonance at l=114.44 ppm
(Table 5). The 1H-NMR (CDCl3, +25°C) spectrum
shows the expected resonances for 1 and 2, which is
confirmed by the crystal structure that there is NCMe
in the complexes at l=2.20 and 2.05 ppm, respectively.
The starting materials used in this research,
[MI2(CO)(NCMe)(h2-EtC2Et)2] (M=Mo or W) were
prepared by reacting the seven-coordinate complexes,
[MI2(CO)3(NCMe)2] with 3-hexyne [30]. Reaction of
equimolar
quantities
of
[MoI2(CO)(NCMe)(h2-
EtC2Et)2] and P(OR)3 (R=Ph or iPr) in diethyl ether at
room temperature gave the new mixed ligand com-
plexes, [MoI2(CO)(NCMe){P(OR)3}(h2-EtC2Et)] (1 and
2) in high yield, via displacement of one of the 3-hexyne
ligands. Complexes 1 and 2 have been fully character-
ised by elemental analysis (C, H and N) (Table 1), IR
1
(Table 2), H-, 13C{1H}-NMR spectroscopy (Tables 3
and 4) and 31P-NMR for complex 1 only (Table 5), and
X-ray crystallography for R=Ph (complex 1). Both
complexes 1 and 2 are very soluble in polar chlorinated
solvents such as CH2Cl2 and CHCl3, and also soluble in
diethyl ether. The complexes are very air-sensitive in
solution, but can be stored under dinitrogen for several
3
The C{1H}-NMR spectra for the complexes 1 and 2
show alkyne contact carbon resonances at l=193.0
and 196.85 ppm, respectively, which from Templeton
and Ward’s [35] correlation of the alkyne contact car-
bon resonances to the number of electrons donated by
the 3-hexyne is acting as a 4-electron donor to the
molybdenum centre. This also conforms with com-
plexes 1 and 2 obeying the effective atomic number
rule.
months
(−17°C)
without
any
significant
decomposition.
The IR spectra (CHCl3) (Table 2) for both complexes
have, as expected single carbonyl bands at 1983 and
1986 cm−1, respectively. These are similar to the three
closely related crystallographically characterised com-
2.2. The synthesis and characterisation of the
bis(3-hexyne) tungsten complexes
plexes,
[MoI2(CO)(NCMe){P(OPh)3}(h2-RC2R%)],
i
{R=R%=Me, w(CO)=1995 cm−1; Ph, w(CO)=2013
cm−1; R=Me, R%=Ph, w(CO)=2000 cm−1 [32]. The
IR spectra of 1 and 2 also show weak nitrile bands at
2286 cm−1, and alkyne stretching bands at 1646 and
1616 cm−1, respectively. These alkyne stretching bands
are at lower wavenumber compared to the uncoordi-
nated 3-hexyne ligand, due to the back-donation of
electron density from the filled d-orbitals to empty
p*-antibonding orbitals on the 3-hexyne ligand, which
[WI2(CO){P(OR)3}(p2-EtC2Et)2] (R=Me, Pr and Ph)
(3–5)
Treatment
of
equimolar
quantities
of
[WI2(CO)(NCMe)(h2-EtC2Et)2] and P(OR)3 (R=Me,
iPr or Ph) in diethyl ether at r.t. gave the acetonitrile
replaced bis(3-hexyne) complexes, [WI2(CO){P(OR)3}-
(h2-EtC2Et)2] (3–5) in high yield. Complexes 3–5 have
been fully characterised by elemental analysis (Table 1),

230
M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
IR (Table 2), 1H- and 31P{1H}-NMR spectroscopy
(Tables 3 and 5). Complex 4 was also characterised by
13C{1H}-NMR spectroscopy (Table 4).
The solubilities and air stabilities of 3–5 are similar
to complexes 1 and 2. They are slightly more soluble
and stable than 1 and 2. This differing reactivity of the
molybdenum and tungsten complexes [MI2(CO)-
(NCMe)(h2-EtC2Et)2] with one equivalent of P(OR)3 is
not unexpected, as we have previously observed similar
differences. For example, reaction of equimolar
amounts of [MoI2(CO)(NCMe)(h2-MeC2Me)2] and
2,2%-bipy(bipy) gave the neutral molybdenum mono-
Table 1
Physical and analytical data a for the complexes (1–23)
Number Complex
Colour
Yield (%)
Analysis (%)
C
H
N
1
2
3
4
5
6
7
8
9
[MoI2(CO)(NCMe){P(OPh)3}(h2-EtC2Et)]
[MoI2(CO)(NCMe){P(OiPr)3}(h2-EtC2Et)]
[WI2(CO){P(OMe)3}(h2-EtC2Et)2]
Brown
Brown
Green
Green
Green
Brown
Brown
Brown
Brown
84
76
79
85
80
42
57
43
62
40.0
(39.9)
30.1
(30.5)
24.1
(24.3)
31.2
(31.5)
38.2
(38.8)
40.3
(39.1)
46.8
(47.3)
42.9
3.5
(3.5)
4.7
(4.8)
4.2
(3.9)
5.4
(4.9)
3.5
(3.8)
4.9
(3.2)
3.9
(3.8)
5.5
1.7
(1.7)
2.0
(2.0)
[WI2(CO){P(OiPr)3}(h2-EtC2Et)2]
[WI2(CO){P(OPh)3}(h2-EtC2Et)2]
[MoI2(CO)2{P(OPh)3}(h2-EtC2Et)]
[MoI2(CO)(PPh3){P(OPh)3}(h2-EtC2Et)]·CH2Cl2
[MoI2(CO){P(OiPr)3}{P(O(Ph)3}(h2-EtC2Et)]·Et2O
(43.3)
44.5
(45.3)
(5.4)
3.6
(3.5)
[MoI2(CO)(LMo){P(OPh)3}(h2-EtC2Et)]
{LMo=[MoI2(CO)3{MeC(CH2PPh2)3-P,P%}]}
10
[MoI2(CO)(LW){P(OPh)3}(h2-EtC2Et)]
Brown
36
42.5
(43.2)
3.4
(3.4)
{LW=[WI2(CO)3{MeC(CH2PPh2)3-P,P%}]}
11
12
13
14
15
16
17
18
19
20
21
22
23
[MoI2(CO)(2,2%-bipy)(h2-EtC2Et)]
Brown
Green
Brown
Brown
Brown
Green
Brown
Green
Brown
Green
Brown
Green
Green
45.4
(45.4)
46.2
(46.2)
40.3
(40.2)
42.5
(42.5)
22.1
(22.1)
19.2
(19.6)
28.6
(28.8)
27.8
(28.9)
33.9
(34.3)
31.4
(31.1)
38.5
(38.8)
38.0
(37.5)
43.5
3.7
(3.6)
4.0
(4.0)
4.1
(4.0)
4.5
(4.3)
4.0
(4.0)
3.5
(3.5)
5.2
(5.1)
5.0
(5.2)
5.9
(6.0)
5.6
(5.4)
6.7
(6.7)
6.6
(6.6)
3.9
3.2
(3.0)
[MoI2(CO){PPh2(CH2)2PPh2}(h2-EtC2Et)]
[MoI(CO)(S2CNMe2){P(OPh)3}(h2-EtC2Et)]CH2Cl2
[MoI(CO)(S2CNEt2){P(OPh)3}(h2-EtC2Et)]·CH2Cl2
[MoI2(CO){P(OMe)3}2(h2-EtC2Et)]
[WI2(CO){P(OMe)3}2(h2-EC2Et)]
92
36
53
78
57
41
49
77
91
56
54
80
1.9
(1.7)
1.7
(1.6)
[MoI2(CO){P(OEt)3}2(h2-EtC2Et)]
[WI2(CO){P(OEt)3}2(h2-EtC2Et)]·Et2O
[MoI2(CO){P(OiPr)3}2(h2-EtC2Et)]
[WI2(CO){P(OiPr)3}2(h2-EtC2Et)]
[MoI2(CO){P(OnBu)3}2(h2-EtC2Et)]
[WI2(CO){P(OnBu)3}2(h2-EtC2Et)]·Et2O
[WI2(CO){P(OPh)3}2(h2-EtC2Et))
(44.2)
(3.5)
a Calculated values in parentheses.

M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
231
Table 2
Infrared data for the phosphite complexes 1–23
Complex
w(CꢁO) (cm−1
)
w(CꢁC) (cm−1
)
w(CꢁN) (cm−1
)
1
2
3
4
5
6
7
8
1983(s)
1986(s)
2044(s)
2046(s)
2064(s)
2040(s)
1963(s)
1967(s)
1646(w)
1616(w)
1653(w)
1636(w)
1636(w)
1641(w)
1590(w)
1594(w)
1648(w)
1636(w)
1638(w)
1656(w)
1590(w)
1736(w)
1636(w)
1654(w)
2286(vw)
2286(vw)
9
2042(s); 1971(s); 1938(s); 1859(s)
2037(s); 1962(s); 1904(s); 1852(s)
1949(s)
1941(s)
2039(s)
2034(s)
2004(s); 1989(sh)
10
11
12
13
14
15
16
17
18
19
20
21
22
23
1988(s); 1953(sh)
1986 a(s); 1956 a(sh); 1995 b(s); 1967 b(sh)
1630(w); 1626(w)
1636(w); 1625(w)
1602(w)
1727(w)
1636(w)
1981 a(s); 1956 a(sh); 1938 b(s); 1987 b(sh)
1966(s)
1950(s)
1968(s); 1996(sh)
1951(s); 2002(sh)
1976(s)
1602(w)
1631(w)
a Spectra recorded in CHCl3 as thin films between NaC1 plates; s=strong, sh=shoulder, w=weak, vw=very weak.
b Spectra recorded in the solid state as KBr discs.
(2-butyne) complex [MoI2(CO)(bipy)(h2-MeC2Me)]
[29], whereas, the reaction of equimolar amounts of
[WI2(CO)(NCMe)(h2-MeC2Me)2] and bipy gave the
typical for other bis(alkyne) complexes of this type
previously described [1,2,38].
cationic
complex,
[WI(CO)(bipy)(h2-MeC2Me)2]I,
2.3. Reactions of
[MoI2(CO)(NCMe){P(OPh)3}(p2-EtC2Et)] (1)
which was crystallographically characterised as its
[BPh4]− salt [37].
The IR spectra (Table 2) of 3–5, all have carbonyl
bands above 2000 wavenumbers, which would be ex-
pected for complexes of the type, [WI2(CO)L(h2-
RC2R%)2]. They also have, as expected, alkyne stretching
bands at lower wavenumber compared to the uncoordi-
nated 3-hexyne. Several unsuccessful attempts were
made to grow single crystals for X-ray crystallography
In
a
recent study [32], the reactions of
[MoI2(CO)(NCMe)(h2-RC2R%)2] with one equivalent of
P(OPh)3 to give the three crystallographically character-
ised
complexes,
[MoI2(CO)(NCMe){P(OPh)3}(h2-
RC2R%)] (R=R%=Me or Ph; R=Me, R%=Ph), were
described. However, no reactions were attempted with
these new mono(phosphite) complexes. In this section,
the chemistry of the crystallographically characterised
complex, [MoI2(CO)(NCMe){P(OPh)3}(h2-EtC2Et)] (1)
is discussed. The first simple reaction was carried out by
bubbling carbon monoxide through an Et2O solution of
1, which gives the acetonitrile replaced product,
[MoI2(CO)2{P(OPh)3}(h2-EtC2Et)] (6), which has been
characterised in the normal manner (see Tables 1–5).
However, after a number of attempts it was not possi-
ble to obtain a satisfactory elemental analysis of this
complex, due to its instability. The IR spectrum
(CHCl3) for [MoI2(CO)2{P(OPh)3}(h2-EtC2Et)] has a
single carbonyl band at 2040 cm−1, which is as ex-
pected much higher than for 1, which has w(CO)=1983
cm−1. The molybdenum(II) complex will likely have
two trans strong p-accepting CO groups, an electron
deficient phosphite, P(OPh)3 and 3-hexyne ligand,
of
3–5,
however,
since
the
reactions
of
[WI2(CO)(NCMe)(h2-RC2R)2] (R=Me or Ph) with a
range of monodentate neutral donor ligands always go
with retention of configuration, it is very likely the
reactions
of
equimolar
amounts
of
[WI2(CO)(NCMe)(h2-EtC2Et)2] and P(OR)3 will also
proceed in the same way. The most likely structure for
3–5 is shown in Fig. 2, since the crystal structures of a
range of complexes, [MI2(CO)(NCMe)(h2-RC2R%)2]
have this geometry [1,2,36–40].
The 13C{1H}-NMR spectrum for complex 4 shows
alkyne contact carbon resonances at l=166.8 and
169.5 ppm, which suggests [35] that the two 3-hexyne
ligands are donating an average of 3 electrons each to
the tungsten centre, which also enables this complex to
obey the effective atomic number rule. This is very

232
M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
Table 3
which leaves little excess electron density on the metal
to back-donate into the empty p*-orbitals of the carbon
monoxide ligands. The 13C{1H}-NMR spectrum of 6
has a single alkyne, (CꢁC) resonance at l=198.74
ppm, which indicates [35] that the 3-hexyne is utilizing
both of its filled p-orbitals and donating 4-electrons to
the molybdenum in this complex.
1H-NMR data for the complexes 1–23 a
Complex 1H-NMR (d ppm)
1
2
7.25–7.5 (m, 15H, 3Ph), 3.4–3.6 (q, 4H, 2CH2), 2.20
(s, 3H, NCMe), 1.25 (t, 6H, 2CH3)
4.2–4.8 (m, 3H, OCH), 3.4 (q, 4H, 2CH2), 2.05 (s, 3H,
NCMe), 1.9 {d, 9H, JHꢀH=6.76 Hz, 3OCH(CH3)2},
1.3 (d, 9H, JHꢀH=6.1 Hz, 3OCH(CH3)2}, 1.2 (s, 6H,
2CH3)
3.7 (d, 3H, JHꢀH=7.35, CH3), 3.5 (d, 6H, JHꢀH=5.34,
2CH3), 3.6 (q, 4H, 2CH2 hexyne), 1.1 (t, 6H, 2CH3
hexyne)
4.6–4.4 (m, 3H phosphite, 3CH), 3.6–3.4 (q, 8H hexyne,
4CH2), 1.35 (t, 12H hexyne, 4CH3), 1.15 (t, 18H, 6CH3
phosphite)
7.5–7.1 (vbr, 15H, 3Ph), 3.6–3.1 (q, 8H, 4CH2), 1.4–1.0
(t, 12H, 4CH3)
7.5–6.8 (m, 15H, 3Ph), 3.4 (m, 4H, 2CH2 hexyne), 1.4
(t, 6H, 2CH3 hexyne)
7.6–7.0 (vbr, 30H, 6Ph), 5.2 (s, 2H, CH2Cl2), 3.3–2.8
(q, 4H, 2CH2), 1.0–0.8 (t, 6H, 2CH3)
7.6–6.9 (m, 15H, 3Ph) 4.7 (m, 3H, 3CHiPr), 4.8 (q, 4H,
Equimolar quantities of 1 and L {L=PPh3, P(OiPr)3,
[MI2(CO)3{MeC(CH2PPh2)3-P,P%}] (M=Mo, W)} I re-
act in CH2CI2 at r.t. to give the acetonitrile replaced
products, [MoI2(CO)L{P(OPh)3}(h2-EtC2Et)] (7–10).
Complexes 7–10 have been fully characterised (see
Tables 1–3 and 5 except complexes (7) and (10), and as
expected are generally less soluble (L=PPh3,
[MI2(CO)3{MeC(CH2PPh2)3-P,P%}]) than 1–6, but
more stable than these complexes. It should be noted
that the organometallic phosphines, [MI2(CO)3-
{MeC(CH2PPh2)3-P,P%}] (M=Mo or W) have been
prepared by reacting equimolar quantities of
[MI2(CO)3(NCMe)2] and MeC(CH2PPh2)3 in CH2Cl2 at
r.t. [41].
3
4
5
6
7
8
2CH2 hexyne), 3.4 (q, 4H, 2CH2 ether), 1.4 (d, 18H,
i
J
HꢀH=5.60, 6CH3 of Pr), 1.1 (t, 6H, 2CH3), 0.9 (t,
6H, 2CH3 ether)
The complexes (L=PPh3) (7) and {L=P(OiPr)3} (8)
were confirmed as CH2Cl2 and Et2O solvates respec-
tively, by repeated elemental analyses and 1H-NMR
spectroscopy. From the reaction of 1 with CO de-
scribed above, it is very likely the structure of 7–10 will
be with the acetonitrile replaced by L in 1, which is
likely to undergo a trigonal twist to give the geometry
with the two phosphorus donor ligands trans to each
other as shown in Fig. 3. This was observed for the
bis(PPh3) complex, [WI2(CO)(PPh3)2(h2-EtC2Et)] [30]
and other related bis(phosphite) complexes [31,32]. The
IR spectra (Table 2) for 7 and 8 show as expected single
carbonyl bands at 1963 and 1967 cm−1 respectively,
whereas the IR spectra for the complexes 9 and 10 have
bands at 1971 and 1962 cm−1 due to the carbonyl
group on the molybdenum 3-hexyne centre, and three
other bands due to the [MI2(CO)3{MeC(CH2PPh2)3-
P,P%}] units. The IR spectra for the complexes
[MI2(CO)3{MeC(CH2PPh2)3-P,P%}] have bands at
6(CO)=2042, 1938 and 1859 (for M=Mo) and at
2037, 1904 and 1852 cm−1 (for M=W) [41].
9
7.8–7.0 (vbr, 30H, 6Ph), 3.5–3.2 (q, 4H, 2CH2), 2.4–2.1
(m, 6H, 2CH2), 1.3 (s, 3H, 1CH3), 1.2 (t, 6H, 2CH3)
7.7–6.7 (vbr, 30H, 6Ph), 3.6–3.1 (q, 4H, 2CH2), 2.4–2.1
(m, 6H, 2CH2), 1.4–1.15 (t, 6H, 2CH3), 0.8 (s, 3H,
1CH3)
7.3–7.1 (vbr, 24H, 4Ph), 4.0 (s, 4H, 2CH2), 3.5 (q, 4H,
2CH2), 0.85 (t, 6H, 2CH3)
7.4–7.1 (m, 15H, 3Ph), 5.3 (s, 2H, CH2Cl2), 3.8 (q, 4H,
2CH2 hexyne), 3.5 {q, 6H, 2CH3 of (CH3)2NCS2}, 1.4
(t, 6H, 2CH3 hexyne)
7.5–7.1 (m, 15H, 3Ph), 5.3 (s, 2H, CH2Cl2), 4.1–3.8
(m, 4H 2CH2(CH3CH2)2NCS2), 3.8–3.6 (q, 4H, 2CH2
of hexyne), 1.5 {t, 6H, 2CH3 of (CH3CH2)2NCS2), 1.1
(t, 6H, 2CH3 hexyne)
3.95 (br,m, 9H, OMe), 3.65 (br,m, 4H, 2CH2), 3.6 (br,
m, 9H, OMe), 1.35 (br,m, 6H, 2CH3)
3.95 (br,m, 6H, OMe), 3.75 (br,m, 3H, OMe), 3.6 (br,
m, 4H, 2CH2), 3.3 (br,m, 9H OMe), 1.2 (br,m, 6H,
2CH3)
3.9–4.2 (m, 12H, OCH2CH3), 3.1 (m, 4H, 2CH2),
1.0–1.25 (m, 18H, OCH2CH3), 0.9 (m, 6H, CH3)
4.75 (m, 12H, 6CH2), 3.1 (m, 4H, 2CH2), 1.4 (m, 18H,
OCH2CH3), 1.1 (m, 6H, 2CH3 of hexyne)
4.75 (m, 6H, OCH2), 3.65 (q, 4H, 2CH2), 1.3 (t, 6H,
2CH3 of hexyne), 1.2 {d, 36H, JHꢀH=1.21 Hz,
6OCH(CH3)2}
4.5–4.8 (m, 6H, OCH), 3.5 (q, 4H, 2CH2 of hexyne),
1.36 {d, 18H, JHꢀH=6.08 Hz, 3OCH(CH3)2}, 1.2 (d,
18H, JHꢀH=6.15 Hz, 3OCH(CH3)2), 0.85 (t, 6H, CH3
of hexyne)
3.85 (m, 12H, 2OCH2), 1.15–1.70 (m, 36H
OCH2CH2CH2CH3), 0.7–0.9 (m, 18H,
OCH2CH2CH2CH3), 0.7–0.9 (m, 6H, 2CH3 of hexyne)
3.9 (md, 12H, 6OCH2, OCH2CH3), 3.65 (m, 4H,
2CH2CH2CH2CH3), 1.80–1.20 (m, 24H, OCH2CH2CH3),
0.85 (m, 18H, 6CH3), 0.85 (m, 6H, 2CH3)
7.3–6.6 (vbr, 30H, 6Ph), 3.5–3.1 (mq, 4H, 2CH2),
1.3–1.1 (t, 6H, 2CH3)
10
12
13
14
15
16
17
18
19
Reaction
of
[MoI2(CO)(NCMe){P(OPh)3}(h2-
‚
EtC2Et)] (1) with an equimolar amount of L L
20
‚
(L L=bipy or dppe) afforded the new complexes
[MoI2(CO)(L L)(h2-EtC2Et)] (11 or 12) in high yield,
‚
via displacement of the acetonitrile and triphenylphos-
21
22
23
phite ligands. Complexes 11 and 12 were characterised
1
by elemental analysis (Table 1), IR (Table 2), H-NMR
spectroscopy (Table 3) and by 31P-NMR spectroscopy
(Table 5), and X-ray crystallography for the bis-
(diphenylphosphino)ethane complex, [MoI2(CO)(dppe)-
(h2-EtC2Et)] (12). Complexes 11 and 12 are consider-
ably less soluble than 1–10 as they do not contain a
solubilising phosphite ligand. They are both more air-
stable in both the solid state and solution com-
a Spectra recorded in CDCl3 (+250C) and referenced to SiMe4;
s=singlet, br=broad, d=doublet, m=multiplet, q=quartet, t=
triplet.

M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
233
Table 4
The crystal data and structural refinement are given
13C{1H}-NMR data (5 ppm) for selected complexes a
,
in Table 6. Selected bond lengths (A) and angles (°) are
given in Table 7. The structure consists of discrete
molecules of [MoI2(CO)(dppe)(h2-EtC2Et)] (12). Al-
though the structure is disordered over a crystallo-
graphic mirror plane, the structure of an individual
molecule has been unequivocally established. Each
metal atom occupies an octahedral environment with
the hexyne ligand occupying one site.
Complex
13C (l ppm)
1
5.40 (s, NCMe), 14.36, 15.26 (2s, 2CH3), 32.80 (s,
2CH3), 115.45, 120.41, 121.04, 121.11, 130.16 (s,
OPh), 149.62, 149.77 (s, CꢁN), 193.0 (s, CꢁC),
208.40(s, CꢁO)
5.7 (s, NCMe), 14.40, 15.02, 15.34 (3s, 2CH3), 31.30
(s, 2CH2), 65.93, 66.31(2s, OCH(CH3)2), 135.0 (s,
CꢁN), 196.85 (s, CꢁC), 233.90 (s, CꢁO)
12.70,13.03, 15.25 (3s, 4CH3 of hexyne), 23.81, 23.87
(2s, 6CH3 phosphite), 31.18,31.41(2s, 4CH2 hexyne),
65.81 (s, 3CH phosphite), 166.8, 169.5 (s, CꢁC),
202.27, 204.39 (s, CꢁO)
24.95(s, 2CH3 of hexyne), 32.84, 34.27 (s, 2CH2
hexyne), 115.44, 120.178,121.18,125.80, 126.62,
129.55, 129.97, 130.20 (s, 3Ph), 198.74 (s, CꢁC),
204.18 (s, CꢁO)
14.36 (br,s, 2CH3), 32.55 (br,s, 2CH2), 53.95 (br,s,
OCH3), 235.0 (br,s, CꢁC)
12.62, 20.28 (br,s, 2CH3), 31.45 (br,s, 2CH2), 52.12,
54.27 (br,s 2OCH3), 207.5 (br,s, CꢁC), 222.5 (br,s,
CꢁO)
18.68, 23.60 (br,s, 2CH3), 32.32, 32.41, 35.47 (br,s,
2CH2), 65.44, 65.52, 67.38 (br,s, OCH2CH3), 195.0
(br,s, CꢁC), 200.99 (s, CꢁO)
15.78, 15.89, 16.60 (br,s, 2CH3), 31.41, 33.61 (br,s,
2CH2), 61.74, 61.82, 62.62,63.29, 63.40, 63.50 (br,s,
OCH2CH3), 203.0, 205.0 (br,s, CꢁC), 227.7 (s, CꢁO)
21.93, 22.85, 24.02 (s, 2CH3), 30.51, 30.98, 31.34,
32.20, 34.59 (s, 2CH2), 65.79, 67.39, 69.57, 70.59,
70.72, 71.772 (s, OCH(CH3)2), 207.82, 208.01 (2s,
CꢁC), 236.21 (s, CꢁO)
23.58, 23.65, 23.94 (s, 2CH3), 31.15, 31.38 (s, 2CH2),
65.78, 67.35, 68.50 (s, OCH(CH3)2), 205.30 (s, CꢁC),
236.12 (s, CꢁO)
2
4
,
The dppe ligand {MoꢀP(2) 2.545(4) A} together with
,
an iodide {Mo(1)ꢀI(1) 2.759(3) A}, and a carbonyl
,
group {Mo(1)ꢀC(l00) 2.00(4) A} occupying an equato-
rial plane, and the hexyne {Mo(1)ꢀC(3) 2.01(2) and
,
Mo(1)ꢀC(4) 2.08(3) A} together with the second iodide
6
,
{Mo(1)ꢀI(2) 2.853(4) A} occupying the axial site. In
this coordination sphere C(l00), I(1) and (4) are disor-
dered over two sites related by the mirror plane, and
are given 50% occupancy in the refinement. As in 1, the
MoꢀI bond trans to the hexyne is significantly longer
than the bond trans to phosphorus.
This arrangement in the coordination sphere con-
trasts with that observed in [WI2(CO)(dppm)(h2-
MeC2Ph)] [27] and [WI2(CO)(dppm)(h2-MeC2Me)] [10],
where the two phosphorus atoms are trans to an iodide
and the 3-hexyne, with the second iodide trans to the
carbonyl. The difference in the structure of 12 may be
due to the increased bite of dppe compared to dppm,
15
16
17
18
19
Table 5
31P{1H}-NMR data l (ppm) for complexes 1–23 a
20
21
Complex
31P{1H} l (ppm)
13.51,13.68, 13.82 (3s, 2CH3), 32.33, 32.58, 32.67 (3s,
2CH2), 65.42, 65.51,66.12, 66.39, 66.73,66.86 (s,
OCH2CCH2CH2CH3), 203.40 (s, CꢁC), 236.29 (s,
CꢁO)
12.56,13.31, 14.22, 14.45 (s, 2CH3), 29.13, 29.31,
29.76, 31.97 (s, 2CH2), 115.50, 117.38, 121.04, 121.12,
128.69, 129.50 (s, 6Ph), 204.69 (s, CꢁC), 219.81(s,
CꢁO)
1
3
4
5
6
8
9
114.44 {s, P(OPh)3}
104.98 {s, Jwꢀp=205.53 Hz, P(OiPr)3}
94.76 {s, Jwꢀp=211.6 Hz, P(OiPr)3}
92.26 {s, P(OPh)3}
23
111.22 {s,P(OPh)3}
127.33 {s, P(OPh)3}; 110.88 {s, P(OiPr)3}
(17.58, 2P of LMo and 32.17, 1P of LMo); 114.50 {s,
P(OPh)3}
a Spectra recorded in CDCl3(+25°C) and referenced to SiMe4;
s=singlet, br=broad, d=doublet, m=multiplet, q=quartet, t=
triplet.
12
13
14
16
31.35 (s,dppe)
128.01 {s, P(OPh)3}
127.26 {s, P(OPh)3}
105.06 {s, trans, JPꢀW=259.14 Hz, P(OMe)3}; 98.0
(d, cis, JPꢀW=97 Hz, P(OMe)3}; 109.25 {d, cis,
J
PꢀP=61.97 Hz, P(OMe)3}
pared to complexes 1–10. There are many complexes
18
100.3 {s, trans, JWꢀP=273.36 Hz, P(OEt)3}; 107.40
{d, cis, JPꢀP=20.24 Hz, P(OEt)3}; 92.50 {d, cis,
‚
known of the general formula [MI2(CO)(L L)(h2-
RC2R%)], including the following complexes [MoI2-
(CO)(5,6-Me2-1,10-Phen)(h2-PhC2Ph)] [29], [WI2(CO)-
(dppm)(h2-MeC2R)] (R=Me [10], R=Ph [27]) and
[WI2(CO){Ph2P(CH2)3PPh2}(h2-EtC2Et)] [30], which
have been structurally characterised. Suitable single
crystals for X-ray crystallography of [MoI2(CO)-
(dppe)(h2-EtC2Et)] (12) were grown by cooling
(−17°C) a CH2Cl2–Et2O (80:20) solution of 12. The
structure of 12 is shown in Fig. 4, together with the
atom numbering scheme.
J
PꢀP=20.24 Hz, P(OEt)3}
19
20
21
105.49 {s, trans, P(OiPr)3}
94.74 {s, trans, JWꢀP=227.73 Hz, P(OiPr)3}
109.38 {s, trans, P(OnBu)3}; 127.28 {d, cis,
J
J
PꢀP=35.44 Hz, (P(OnBu)3}; 117.75 {d, cis,
PꢀP=35.44Hz, P(OnBu)3}
22
99.38 {s, trans, JWꢀP=211.21 Hz, P(OnBu)3}; 107.08
{d, JPꢀP=29.97 Hz, P(OnBu)3}; 100.74 {d, cis,
J
PꢀP=29.97 Hz, P(OnBu)3}
23
92.45 {s, trans, JPꢀP=207.58 Hz, P(OPh)3}
a Spectra recorded in CDCl3 (+25°C) and referenced to H3PO4.

234
M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
Fig. 1. The structure of 1 with ellipsoids shown at 30% probability.
Table 6
Crystal data and structure refinement for 1, 12, 19 and 20
Compound
1
12
19
20
Empirical formula
Molecular weight
Temperature (K)
C
811.21
293(2)
27H28I2MoNO4P
C33H34MoOP2
858.28
293(2)
C25H52I2O7P2Mo
876.35
293(2)
C25H52I2O7P2W
964.26
293(2)
,
Wavelength (A)
0.71073
Monoclinic
P21/a
0.71073
Orthorhombic
Pnam(No 62)
0.71073
Orthorhombic
P22121
0.71073
Orthorhombic
P22121
Crystal system
Space group
Unit cell dimensions
,
a (A)
16.36(2)
12.484(14)
16.604(17)
113.78(1)
3102
15.555(17)
10.058(12)
21.59(2)
(90)
3378
4
1.688
2.334
1672
0.25×0.17×0.10
2.41–25.91
−165h516
05k512
−265l526
7369
9.628(9)
14.087(17)
14.073(17)
(90)
1909
2
1.525
2.078
872
0.25×0.25×0.10
2.94–26.04
05h510
−175k517
−1751517
6568
9.689(9)
13.983(17)
14.015(17)
(90)
1899
2
1.687
4.785
936
0.25×0.20×0.05
2.10–26.08
05h511
−165k517
−175l517
6083
,
b (A)
,
c (A)
i (°)
V (A )
3
,
Z
4
Dcalc (Mg m−3
)
1.737
2.495
1568
0.25×0.25×0.10
2.11–26.01
−205h520
05k515
−205l520
10520
Absorption coefficient (mm−1
F(000)
)
Crystal size (mm3)
Theta range for data collection (°)
Index ranges
Reflections measured
Independent reflections [Rint
Data/restraints/parameters
]
5631/0.0845
5631/0/328
2375/0.0701
2375/0/118
3472/0.0719
3472/45/117
3581/0.1118
3581/46/117
R indices (I\2|(I))
R1
wR2
0.0728
0.1845
0.0806
0.2205
0.0743
0.2020
0.0797
0.2162
R indices (all data)
R1
0 1834
0.1262
0.1496
0.1620
wR2
0.2286
1.495, −0.790
0.2494
1.365, −0.856
0.2390
0.847, −0.593
0.2607
1.297, −0.904
Largest diff. peak and hole (e A−3
)

M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
Table 7 (Continued)
235
Table 7
,
Bond lengths (A) and angles (°) in the metal coordination spheres for
M(1)ꢀP(4)
M(1)ꢀI(2)
2.565(5)
2.872(2)
40.3(6)
105.1(12)
65.0(9)
87.0(13)
92.2(1)
92.0(4)
96.7(13)
92.6(2)
90.0(4)
175.2(3)
160.1(9)
94.7(6)
134.8(1)
88.1(3)
87.9(3)
172.9(10)
134.8(5)
69.9(9)
88.7(3)
90.3(1)
2.541(8)
2.853(3)
40.0(5)
107.1(14)
67.2(11)
89(2)
92.2(2)
91(3)
94(2)
1, 12, 19 and 20
C(11)ꢀM(1)ꢀC(21)
C(11)ꢀM(1)ꢀC(100)
C(21)ꢀM(1)ꢀC(100)
C(11)ꢀM(1)ꢀP(4)
C(21)ꢀM(1)ꢀP(4)
C(100)ꢀM(1)ꢀP(4)
C(11)ꢀM(1)ꢀP(4) b
C(21)ꢀM(1)ꢀP(4) b
C(100)ꢀM(1)ꢀP(4) b
P(4)ꢀM(1)ꢀP(4) b
C(100)ꢀM(1)ꢀI(2)
C(11)ꢀM(1)ꢀI(2)
C(21)ꢀM(1)ꢀI(2)
P(4)ꢀM(1)ꢀI(2)
For 1
Mo(1)ꢀC(100)
Mo(1)ꢀC(3)
Mo(1)ꢀC(4)
Mo(1)ꢀN(200)
Mo(1)ꢀP(4)
Mo(1)ꢀI(3)
Mo(1)ꢀI(2)
1.948(14)
2.007(12)
2.040(13)
2.212(13)
2.485(4)
2.799(3)
2.862(3)
112.5(5)
74.0(5)
92.3(2)
91(3)
C(100)ꢀMo(1)ꢀC(3)
C(100)ꢀMo(1)ꢀC(4)
C(3)ꢀMo(1)ꢀC(4)
C(100)ꢀMo(1)ꢀN(200)
C(3)ꢀMo(1)ꢀN(200)
C(4)ꢀMo(1)ꢀN(200)
C(100)ꢀMo(1)ꢀp(4)
C(3)ꢀMo(1)ꢀP(4)
C(4)ꢀMo(1)ꢀP(4)
N(200)ꢀMo(1)ꢀP(4)
C(100)ꢀMo(1)ꢀI(3)
C(3)ꢀMo(1)ꢀI(3)
C(4)ꢀMo(1)ꢀI(3)
N(200)ꢀMo(1)ꢀI(3)
P(4)ꢀMo(1)ꢀI(3)
C(100)ꢀMo(1)ꢀI(2)
C(3)ꢀMo(1)ꢀI(2)
C(4)ꢀMo(1)ꢀI(2)
N(200)ꢀMo(1)ꢀI(2)
P(4)ꢀMo(1)ꢀI(2)
I(3)ꢀMo(1)ꢀI(2)
175.6(4)
157.5(11)
95.4(5)
135.3(1)
89.6(6)
87.3(6)
174.4(13)
135.6(1)
68.5(11)
87.3(6)
89.0(1)
38.5(5)
166.0(5)
80.6(5)
118.8(5)
87.1(4)
90.3(3)
89.0(4)
98.2(3)
90.4(4)
99.1(3)
P(4) b2ꢀM(1)ꢀI(2)
C(11)ꢀM(1)ꢀI(2) b
C(21)ꢀM(1)ꢀI(2) b
C(100)ꢀM(1)ꢀI(2) b
P(4)ꢀM(1)ꢀI(2) b
I(2)ꢀM(1)ꢀI(2) b
99.0(4)
82.3(3)
a Symmetry element x, y,.5−z for 20
b Symmetry element x, 5−y, 1−z for 19 and 20.
170.6(1)
83.9(4)
160.7(4)
155.8(4)
84.3(3)
but may also be due to stabilising packing effects in the
disordered structure. It is interesting to note that the
bidentate ligands, bipy and dppe in these reactions
80.0(1)
90.7(1)
displace both
a
nitrile and
a
P(OPh)3 ligand.
For 12
Mo(1)ꢀC(100)
Mo(1)ꢀC(3)
Mo(1)ꢀC4)
Mo(1)ꢀP(2)
Mo(1)ꢀI(1)
Mo(1)ꢀI(2)
Triphenylphosphite is the most weakly bonding of the
series P(OR)3 (R=Me, Et, Pr, Ph), and might be
expected to be displaced in this type of reaction rather
than an iodo or a carbonyl ligand. Complexes 11 and
12 have single carbonyl bands at 1949 and 1941 cm−1
respectively, in the expected position for this type of
complex. The 1H-NMR spectra for 12 conform with the
2.00(4)
2.01(2)
2.08(3)
2.545(4)
2.759(3)
2.853(4)
112.4(10)
70.9(12)
41.7(8)
160.1(10)
85.6(5)
127.2(4)
92.7(9)
85.6(5)
91.0(7)
80.0(2)
88.3(9)
101.4(4)
96.9(7)
96.4(1)
171.9(1)
79.2(1)
163.1(6)
148.8(7)
81.5(1)
90.8(1)
C(100)ꢀMo(1)ꢀC(3)
C(100)ꢀMo(1)ꢀC(4)
C(3)ꢀMo(1)ꢀC(4)
C(100)ꢀMo(1)ꢀP(2) a
C(3)ꢀMo(1)ꢀP(2) a
C(4)ꢀMo(1)ꢀP(2) a
C(100)ꢀMo(1)ꢀP(2)
C(3)ꢀMo(1)ꢀP(2)
C(4)ꢀMo(1)ꢀP(2)
P(2) aꢀMo(1)ꢀP(2)
C(100)ꢀMo(1)ꢀI(1)
C(3)ꢀMo(1)ꢀI(1)
C(4)ꢀMo(1)ꢀI(1)
P(2) aꢀMo(1)ꢀI(1)
P(2)ꢀMo(1)ꢀI(1)
C(100)ꢀMo(1)ꢀI(2)
C(3)ꢀMo(1)ꢀI(2)
C(4)ꢀMo(1)ꢀI(2)
P(2)ꢀMo(1)ꢀI(2)
I(1)ꢀMo(1)ꢀI(2)
[MoI2(CO)(dppe)(h2-EtC2Et)]
formulation.
The
31P{1H}-NMR spectrum (CDCl3, +25°C) for 12 has a
single resonance at l=31.35 ppm, which suggests that
the complex is fluxional at r.t.
Equimolar
quantities
of
[MoI2(CO)(NCMe)-
{P(OPh)3}(h2-EtC2Et)] (1) and NaS2CNR2·nH2O (R=
Me or Et) react in CH2Cl2 at r.t. to give the dithiocar-
bamate
complexes,
[MoI(CO){P(OPh)3}(S2CNR2-
S,S%)(h2-EtC2Et)]·CH2Cl2 (13 and 14) in good yield, via
displacement of the acetonitrile and an iodo ligand. The
new complexes have been characterised in the normal
manner (see Tables 1–3 and 5), and are confirmed as
CH2CI2 solvates by repeated elemental analyses and
1H-NMR spectroscopy. They are both very soluble in
chlorinated solvents, CH2Cl2 and CHCl3, but much less
soluble in diethyl ether. The complexes are air-sensitive
in both the solid state and solution. A number of
dithiocarbamate alkyne complexes of molybdenum(II)
and tungsten(II) have been previously characterised
[42–44], including the crystallographically characterised
complex [WI(CO)(S2CNC4H8)(h2-MeC2Me)2] [44]. It is
For 19 and 20
19 M=Mo
1.93(2)
1.95(2)
20 M=W
1.92(2)
1.95(2)
M(1)ꢀC(11)
M(1)ꢀC(21)
M(1)ꢀC(100)
2.09(3)
2.02(3)

236
M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
Fig. 2. Proposed structure of [WI2(CO){P(OR)3}(h2-EtC2Et)2] (3–5).
Fig. 5. Proposed structure of [MoI(CO){P(OPh)3}(S2CNR)2(h2-
EtC2Et)]·CH2Cl2 (13 and 14).
variety of neutral and anionic ligands, such as 1,10-
phenanthroline, AsPh3, SbPh3 were carried out, and
although reactions occurred, no pure products could be
isolated from these reactions.
Fig. 3. Proposed structure of [MoI2(CO)L{P(OPh)3}(h2-EtC2Et)] (7–
10).
2.4. Synthesis and characterisation of the bis(phosphite)
complexes [MI2(CO){P(OR)3}2(p2-EtC2Et)] (15–23)
likely 13 and 14 will have a similar structure, except the
2-butyne ligand is replaced by a P(OPh)3 ligand, and is
shown in Fig. 5. The IR spectra of 13 and 14 have
single carbonyl bands at 2039s and 2034s cm−1 respec-
tively. The 31P{1H}-NMR spectra of 13 and 14 have
single resonances at 128.01 and 127.26 ppm respec-
tively, due to the triphenylphosphite ligand.
The complexes [MI2(CO)(NCMe)(h2-EtC2Et)2] were
reacted with two equivalents of P(OR)3 in diethyl ether
at r.t. to give the bis(phosphite) complexes
[MI2(CO){P(OR)3}2(h2-EtC2Et)] {M=Mo or W; R=
i
n
Me, Et, Pr, Bu, Ph (for M=W only)} (15-23) in high
yield, via displacement of an acetonitrile and a 3-
hexyne ligand.
It should be noted that a number of other reactions
of [MoI2(CO)(NCMe){P(OPh)3}(h2-EtC2Et)] (1) with a
Fig. 4. The structure of [MoI2(CO)(dppe)(h2-EtC2Et)] (12) with ellipsoids at 30% probability. The structure is disordered over a crystallographic
mirror plane through atoms Mo(1), I(2), C(3), C(2) and C(1). Only one discrete molecule is shown.

M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
237
Suitable single crystals for X-ray analysis of
[MI2(CO){P(OiPr)3}2(h2-EtC2Et)] (19) and (20) were
grown by cooling (−17°C) concentrated diethyl ether
solutions of 19 and 20 for 24 h. The structure of 20
(M=W) is shown in Fig. 6 together with the atomic
numbering scheme. Crystal data and structure refine-
ment for 19 and 20 are given in Table 6 and selected
Complexes 15–23 were characterised by elemental
1
analysis (Table 1), IR (Table 2), H (Table 3), 31P{1H}
(Table 5 except complex 17), and in selected cases
13C{1H}-NMR spectroscopy (Table 4, except complex
22), and for the complexes where M=Mo and W,
R=iPr (19) and (20) by X-ray crystallography. All the
bis(phosphite) complexes were extremely soluble in po-
lar solvents, such as CH2Cl2 and CHCl3, and also in
diethyl ether. They are very air-sensitive in solution, but
can be stored under nitrogen in the solid state at
−17°C for several days.
,
bond lengths (A) and angles (°) are given in Table 7.
The structure consists of discrete molecules of
[WI2(CO){P(OiPr)3}2(h2-EtC2Et)] (20). The structure of
19 with M=Mo is isostructural with 20, M=W. In
both structures the metal atom has a distorted octahe-
dral environment, with the hexyne ligand occupying
one site. The two phosphite ligands are mutually trans
The tungsten complexes [WI2(CO){P(OR)3}2(h2-
n
EtC2Et)] {R=Et (18) and Bu (22)} were confirmed as
1
Et2O solvates by repeated elemental analysis and H-
,
to each other {W(1)ꢀP(4) 2.541 (8) 2 A, Mo(1)ꢀP(4)
NMR spectroscopy. These bis(phosphite)-3-hexyne
complexes are closely related to the complexes,
,
2.565(5) A}. The carbonyl and hexyne groups are mu-
tually cis, and each is trans to an iodide. The WꢀI(2)
i
n
[WI2(CO){P(OR)3}2(h2-R%C2R%)] (R=Me, Et, Pr, Bu;
R%=Me or Ph) (structurally characterised for R=
R%=Me) [31] and the large series of complexes,
[MI2(CO){P(OR)3}2(h2-R%C2R%%)] {R=Ph, R%=Me,
R%%=Ph (M=Mo only); M=Mo or W, R=Me, R%=
R%%=Me, Ph (M=Mo only); R%=Me, R%%=Ph (M=
W only); R=Et, R%=R%%=Me, Ph (M=Mo only);
R%=Me, R%%=Ph (M=W only); R=iPr, R=R%%=
Me, Ph (M=Mo only); R=nBu, R%=R%%=Me, Ph
(M=Mo only for both complexes)} {structurally char-
acterised for M=Mo, R=Me, iPr; R%=R%%=Me;
M=Mo, R=Ph, R%=Me, R%%=Ph; M=W, R=Et
,
and MoꢀI(2) distances are 2.853(3) and 2.872(2) A
respectively. This trans configuration around the metal
has been observed previously [32].
The IR spectra of complexes 15–18, {P(OMe)3} and
{P(OEt)3}, and 21 and 22 {P(OnBu)3} complexes, have
two carbonyl stretching bands in both their solution
(CHCl3) and solid state (KBr disc) spectra, and it is
very likely the carbonyl bands at higher wavenumber
will be due to the cis-isomer. For example, for the
complex [MoI2(CO){P(OEt)3}2(h2-EtC2Et)] (17) has
carbonyl bands w(CꢁO) at 1956 and 1986 cm−1 in
liquid state and 1967 and 1995 cm−1 in the solid state.
For the cis-phosphite isomers, the carbonyl group with
the higher stretching frequencies will be trans to the
i
or Pr; R%=R%%=Me;R%=Me,R%%=Ph (R=iPr only)}
very recently reported [32].
Fig. 6. The structure of [WI2(CO){P(OiPr)3}2(h2-EtC2Et)] (20) with ellipsoids at 30% probability. The structure is disordered over a crystallo-
graphic two-fold axis through the metal atom. Only one discrete molecule is shown. The structure of (19) is isostructural.

238
M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
Scheme 1. Proposed mechanism for the stepwise reactions of two equivalents of phosphite ligands with [MI2(CO)(NCMe)(h2-EtC2Et)2].
i
strong p-accepting phosphite group [32], whereas in the
trans-isomer the carbonyl is trans to an iodo group (see
Fig. 6), which could conform with the lower carbonyl
stretching bands in both the solid and solution state.
The cone angles [45] for P(OR)3 are {R=Me (107°),
R=Me, Et, nBu, Pr; 80:20, 40:60, 40:60 and 0:100
respectively. The ratio between the cis and trans-iso-
mers for the bis{P(OMe)3} complex 16 is approximately
50:50. For the bis{P(OnBu)3}complex 18, the ratio was
10:90, and the ratios for the bis{P(OiPr)3}complexes 19
i
1
Et:nBu (109°), Pr (128°)}, and hence for the larger
and 20 were, as expected, 0:100. The H-NMR spectra
triisopropyl phosphite, it would be expected that a
greater proportion of trans-phosphite complexes for the
larger cone angle phosphite ligands. The 31P{1H}-NMR
data has been used to obtain the cis:trans isomer ratio
of the series of phosphite ligands [MI2(CO){P(OR)3}2-
of 15–18, 21 and 22 all have complex multiplet reso-
nances, which conforms with the mixture of cis- and
trans-isomers in solution.
The 13C{1H)-NMR spectra of complexes, 16–21 and
23 all generally show alkyne contact carbon resonances
above 200 ppm, which conform with the 3-hexyne
ligand donating 4 electrons to the molybdenum or
tungsten in these complexes [35], which also enables the
complexes to obey the effective atomic number
rule.
n
i
(h2-EtC2Et)] (R=Me, Et, Bu or Pr) and were found
to be in similar ratios to those previously observed for
the closely related 2-butyne and 1-phenylpropyne com-
plexes of the type, [MI2(CO){P(OR)3}2(h2-R%C2R%%)]
(R%=R%%=Me; R%=Me, R%%=Ph) [32], which was for

M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
239
2.5. Conclusions
X-ray crystallography. (Yield of pure product=0.29 g,
84%).
A
In conclusion, the synthesis and characterisation of a
number of new 3-hexyne phosphite complexes of
molybdenum(II) and tungsten(II), including the crystal-
lographic characterisation of the mono(phosphite) com-
plex [MoI2(CO)(NCMe){P(OPh)3}(h2-EtC2Et)] (1) has
been described. The chemistry of 1 has been extensively
studied, and one of the reaction products,
[MoI2(CO)(dppe)(h2-EtC2Et)], has been crystallograph-
ically characterised. The synthesis and structures (M=
Mo and W; R=iPr) of a series of bis(phosphite)
complexes [MI2(CO){P(OR)3}2(h2-EtC2Et)] are also de-
scribed. Finally, by considering the results of two previ-
similar reaction of [MoI2(CO)(NCMe)(h2-
EtC2Et)2] with one equivalent of P(OiPr)3 in diethyl
ether at r.t. gave the complex, [MoI2(CO)(NCMe){P-
(OiPr)3}(h2-EC2Et)] (2). For physical and analytical
data see Table 1.
3.1.2. Preparation of [WI2(CO){P(OMe)3}(p2-EtC2Et)2]
(3)
To
a
stirred solution of [WI2(CO)(NCMe)(h2-
EtC2Et)2] (0.25 g, 0.37 mmol) in diethyl ether (20 cm3)
was added P(OMe)3 (0.046 g, 0.37 mmol, 0.044 ml).
After 24 h, filtration and removal of solvent in vacuo,
gave an oily green product, [WI2(CO){P(OMe)3}(h2-
EtC2Et)2] (3), which was dissolved in the minimum
quantity of CH2Cl2–Et2O and cooled to −17°C for 24
h to give small crystals of the pure product. (Yield of
pure product=0.22 g, 79%).
ous
papers
describing
the
reactions
of
[MI2(CO)(NCMe)(h2-RC2R)2] with phosphites [31,32]
with the work described in this paper, a detailed mech-
anism of the reactions of [MI2(CO)(NCMe)(h2-
EtC2Et)2] with phosphites can be described, and is
shown in Scheme 1. This shows the different pathways
that when one equivalent of phosphite is added, to-
gether with the cis-trans-isomerism which occurs due to
the steric effects of the phosphite ligands.
Similar reactions of [WI2(CO)(NCMe)(h2-EtC2Et)2]
with one equivalent of P(OR)3 {R=iPr (4) and Ph (5)}
in diethyl ether at r.t. gave the complexes
[WI2(CO){P(OR)3}(h2-EtC2Et)2] (4) and (5). For physi-
cal and analytical data see Table 1.
3.1.3. Preparation of
3. Experimental
[MoI2(CO)2{P(OPh)3}(p2-EtC2Et)] (6)
To a stirred solution of [MoI2(CO)(NCMe)(h2-
EtC2Et)2] (0.25 g, 0.43 mmol) in CH2C12 (20 cm3) was
added P(OPh)3 (0.13 g, 0.11 ml, 0.43 mmol), and CO
was bubbled through the solution for 30 min. After 24
h, filtration and removal of solvent in vacuo gave an
oily brown product of [MoI2(CO)2{P(OPh)3}(h2-
EtC2Et)] (6), and after repeated recrystallisation it was
not possible to obtain satisfactory elemental analysis
data for the product, which was dissolved in the mini-
mum quantity of CH2Cl2–Et2O and cooled to −17°C
for 24 h to give small crystals of the product. (Yield of
product=0.16 g, 42%).
All preparations described in this paper were carried
out using standard vacuum/Schlenk line techniques.
The starting materials, [MI2(CO)(NCMe)(h2-EtC2Et)2]
(M=Mo, W) were prepared by the published method
[30]. Diethyl ether was dried over sodium wire before
use and CH2Cl2 over calcium hydride before use. All
chemicals used were purchased from commercial
sources.
Elemental analyses (C, H and N) were determined by
using a Carlo Erba Elemental Analyser MOD 1108
(using helium as the carrier gas). IR spectra were
recorded as thin CHCl3 films between NaCl plates or in
the solid state as KBr discs. 1H-, 13C{1H}- and 31P{1H}-
NMR spectra were recorded on a Bruker AC250 MHz
NMR spectrometer.1H and 13C{1H}-NMR spectra
were referenced to SiMe4 and 31P{1H}-NMR spectra
were referenced to 85% H3PO4.
3.1.4. Preparation of
[MoI2(CO)(PPh3){P(OPh)3}(p2-EtC2Et)]·CH2Cl2 (7)
To
a stirred solution of [MoI2(CO)(NCMe){P-
(OPh)3}(h2-EtC2Et)] (0.25 g, 0.30 mmol) in CH2Cl2 (20
cm3) was added PPh3 (0.08 g, 0.31 mmol). After 24 h,
filtration and removal of solvent in vacuo gave the
3.1. Syntheses
brown
product,
[MoI2(CO)(PPh3){P(OPh)3}(h2-
EtC2Et)]·CH2Cl2 (7), which was dissolved in the mini-
mum quantity of CH2Cl2–Et2O and cooled to −17°C
for 24 h to give small crystals of the product. (Yield of
pure product=0.18 g, 57%).
3.1.1. [MoI2(CO)(NCMe){P(OPh)3}(p2-EtC2Et)] (1)
To a stirred solution of [MoI2(CO)(NCMe)(h2-
EtC2Et)2] (0.25 g, 0.43 mmol) in diethyl ether (20 cm3)
was added P(OPh)3 (0.13 g, 0.42 mmol, 0.11 ml). After
24 h, filtration and removal of solvent in vacuo gave the
A
similar
reaction
of
[MoI2(CO)(NCMe)
-{P(OPh)3}(h2-EtC2Et)] with one equivalent of P(OiPr)3
in CH2Cl2 at r.t. and recrystallisation from CH2Cl2–
Et2O gave the complex [MoI2(CO){P(OiPr)3}-
{P(OPh)3}(h2-EtC2Et)]·Et2O (8). For physical and ana-
lytical data see Table 1.
brown
product,
[MoI2(CO)(NCMe){P(OPh)3}(h2-
EtC2Et)] (1), which was dissolved in the minimum
quantity of CH2Cl2–Et2O and cooled to −17°C for 24
h to give small crystals of the product, suitable for

240
M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
3.1.5. Preparation of [MoI2(CO)LMo{P(OPh)3}-
(p2-EtC2Et)] (9) {LMo=[MoI2(CO)3[MeC(CH2PPh2)3 -
P,P%]}
EtC2Et)2] (0.25 g, 0.43 mmol) in diethyl ether (20 cm3)
at r.t. was added P(OMe)3 (0.11 g, 0.86 mmol, 0.11 ml).
After 24 h, filtration and removal of solvent in vacuo
gave
the
oily
brown
product
of
To
a stirred solution of [MoI2(CO)(NCMe){P-
[MoI2(CO){P(OMe)3}2(h2-EtC2Et)] (15), which was dis-
solved in the minimum quantity of CH2Cl2–Et2O and
cooled to −17°C for 24 h to give small crystals of the
product. (Yield of pure product=0.24 g, 78%).
Similar reactions of [MI2(CO)(NCMe)(h2-EtC2Et)2]
with two equivalents of P(OR)3 {M=Mo, R=Et (17),
R=iPr (19), R=nBu (21); M=W, R=Me (16), R=
Et (18), R=iPr (20), R=nBu (22); R=Ph (23)} in
diethyl ether at r.t. gave the complexes,
[MI2(CO){P(OR)3}2(h2-EtC2Et)] (16–23). For physical
and analytical data see Table 1. Suitable single crystals
of the bis{P(OiPr)3} complexes, [MI2(CO){P-
(OiPr)3}2(h2-EtC2Et)] (19 and 20) were grown by cool-
ing concentrated diethyl ether solutions of 19 and 20 to
−17°C for 24 h.
(OPh)3}(h2-EtC2Et)] (0.18 g, 0.25 mmol) in CH2Cl2 (20
cm3) was added at 0°C, [MoI2(CO)3{MeC(CH2PPh2)3-
P,P%}] (0.23 g, 0.22 mmol). After 48 h, filtration and
removal of solvent in vacuo gave the brown product,
[MoI2(CO)(LMo){P(OPh)3}(h2-EtC2Et)] (9), which was
dissolved in the minimum quantity of CH2Cl2–Et2O
and cooled to −17°C for 24 h to give small crystals of
the product. (Yield of pure product=0.25 g, 62%).
A
similar reaction of [MoI2(CO)(NCMe){P-
(OPh)3}(h2-EtC2Et)] with one equivalent of L {LW=
[WI2(CO)3{MeC(CH2PPh2)3-P,P%}] in CH2Cl2 at r.t.
gave the complex, [MoI2(CO)(LW){P(OPh)}(h2-
EtC2Et)] (10). For physical and analytical data see
Table 1.
3.1.6. Preparation of [MoI2(CO)(dppe)(p2-EtC2Et)] (12)
3.2. X-Ray crystallography-crystal structure
determinations
To
a stirred solution of [MoI2(CO)(NCMe){P-
(OPh)3}(h2-EtC2Et)] (0.25 g, 0.31 mmol) in CH2Cl2 (20
cm3) was added dppe (0.12 g, 0.30 mmol). After 3 h,
filtration and removal of solvent in vacuo gave the
green product, [MoI2(CO)(dppe)(h2-EtC2Et)] (12),
which was dissolved in the minimum quantity of
CH2Cl2–Et2O and cooled to −17°C for 24 h to give
small crystals of the product, suitable for X-ray crystal-
lography. (Yield of pure product=0.24 g, 92%).
In a similar reaction of equimolar quantities of
[MoI2(CO)(NCMe){P(OPh)}(h2-EtC2Et)] and 2,2%-
bipyridyl in CH2Cl2 gave the complex, [MoI2(CO)(2,2%-
bipy)(h2-EtC2Et)] (11). See Table 1 for physical and
analytical data.
Crystal data are given in Table 6, together with
refinement details. Data for the four crystals were col-
lected with Mo–Ka radiation using the MARresearch
Image Plate System. The crystals were positioned at 70
mm from the Image Plate. 95 Frames were measured at
20 intervals with a counting time of 4 min. Data
analyses were carried out with the XDS program [46].
The structures were solved using direct methods with
the SHELX 86 program [47]. In 1 all non-hydrogen
atoms were refined using anisotropic thermal parame-
ters. The structure of 12 was disordered over a crystal-
lographic mirror plane with I(1) and the carbonyl
C(100), O(100) on opposite sides. In addition three
atoms of the EtC2Et moiety were on the mirror plane
and three atoms were on one side (or the other). The
two linking carbon atoms of the dppe ligand were also
disordered over 2 sites, but the PPh2 groups conformed
to the crystallographic symmetry. All disordered atoms
were given 50% occupancy. The Mo, I and P atoms
were refined anisotropically and C and O atoms
isotropically. The structures of 19 and 20 were isostruc-
tural and disordered over a two-fold axis and in addi-
tion the crystals were twinned. The cell dimensions
{9.628, 14.087, 14.073 for 19 and 9.689, 13.983, 14.015
3.1.7. Preparation of [MoI(CO){P(OPh)3}-
(S2CNMe2)(p2-EtC2Et)] (13)
To
a stirred solution of [MoI2(CO)(NCMe){P-
(OPh)3}(h2-EtC2Et)] (0.3 g, 0.37 mmol) in CH2Cl2 (20
cm3) at r.t. was added of NaS2CNMe2·2H2O (0.07 g,
0.39 mmol). After 24 h, filtration and removal of
solvent in vacuo gave the oily brown product of
[Mo{(CO)(S2CNMe2){P(OPh)3}(h2-EtC2Et)]·CH2Cl2
(13), which was dissolved in the minimum quantity of
CH2Cl2–Et2O and cooled to −17°C for 24 h to give
small crystals of the product. (Yield of pure product=
0.1 g, 36%).
,
A
for 20} are very similar to those found in
[MoI2(CO){P(OiPr)3}2(h2-MeC2Me)] (9.143, 14.116,
A similar reaction of [MoI2(CO)(NCMe){P(OPh)3}-
(h2-EtC2Et)] with one equivalent of NaS2CNEt2 in
CH2Cl2 at r.t. gave the complex [MoI(CO)(S2CNEt2)-
{P(OPh3)}(h2-EtC2Et)].CH2Cl2 (14). See Table 1 for
physical and analytical data.
i
2
,
14.142 A) and in [WI2(CO){P(O Pr)3}2(h -MeC2Me)]
(9.146, 14.079, 14.072 A) [32], and indeed both 19 and
,
20 proved isostructural with these two structures in
which the 2-butyne and carbonyl groups were disor-
dered over the 2-fold axis. As in these two structures,
19 and 20 were refined successfully in space group
P22121 (No 18) with (010, 001) twinning. The ꢀCO and
ꢀC6H10 moieties were each given 50% occupancy and
3.1.8. Preparation of [MoI2(CO){P(OMe)3}2
(p2-EtC2Et)] (15)
To a stirred solution of [MoI2(CO)(NCMe)(h2-

M. Al-Jahdali et al. / Journal of Organometallic Chemistry 622 (2001) 228–241
241
[12] A. Mayr, C.M. Bastos, J. Am. Chem. Soc. 112 (1990) 7797.
the structure was refined with distance constraints for
these disordered groups. The twin ratios refined to 0.48
(1) in 19 and 0.50(1) in 20. The M (M=W or Mo), I and
P atoms were refined anisotropically and the C, O atoms
isotropically. In all four structures, the hydrogen atoms
were included in geometric positions and given thermal
parameters equal to 1.2 times those of the carbon atoms
to which they were bonded. All four structures were
corrected for absorption using the DIFABS program [48]
and then refined to convergence on F2 using SHELXL [49].
All calculations were carried out on a Silicon Graphics
INDY Workstation at the University of Reading.
[13] A. Mayr, C.M. Bastos, R.T. Chang, J.X. Haberman, K.S.
Robinson, D.A. Belle-Oudry, Angew. Chem. Int. Ed. Engl. 31
(1992) 747.
[14] A. Mayr, C.M. Bastos, N. Daubenspeck, G.A. McDermott,
Chem. Ber. 125 (1992) 1583.
[15] A. Mayr, T.-Y. Lee, Angew. Chem., Int. Ed. Engl. 32 (1993)
1726.
[16] T.-Y. Lee, A. Mayr, J. Am. Chem. Soc. 116 (1994) 10300.
[17] G.R. Clark, A.J. Nielson, A.D. Rae, C.E.F. Rickard, J. Chem.
Soc., Dalton Trans. (1994) 1783.
[18] P.K. Baker, D. ap Kendrick, J. Chem. Soc., Dalton Trans.
(1993) 1039.
[19] P.K. Baker, M.E. Harman, D. ap Kendrick, M.B. Hursthouse,
Inorg. Chem. 32 (1993) 3395.
[20] P.K. Baker, P.D. Jackson, Inorg. Chim. Acta 219 (1994) 99.
[21] P.K. Baker, D.J. Muldoon, A.J. Lavery, A. Shawcross, Polyhe-
dron 13 (1994) 2915.
[22] T. Ajayi-Obe, E.M. Armstrong, P.K. Baker, S. Prakash, J.
Organomet. Chem. 468 (1994) 165.
4. Supplementary material
Crystallographic data for the structural analysis not
included in this paper, has been deposited with the
Cambridge Crystallographic Data Centre, CCDC
156368 for compound 1, CCDC 156369 for compound
12, CCDC 156370 for compound 19, CCDC 156371 for
compound 20. Copies of this information may be ob-
tained free of charge from: The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (Fax: +44-
1223-336-033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
[23] P.K. Baker, K.R. Flower, Polyhedron 13 (1994) 3265.
[24] P.K. Baker, K.R. Flower, Z. Naturforsch. Sect. B 49 (1994)
1544.
[25] P.K. Baker, S.J. Coles, D.E. Hibbs, M.M. Meehan, M.B. Hurst-
house, J. Chem. Soc., Dalton Trans. (1996) 3995.
[26] P.K. Baker, M.M. Meehan, J. Organomet. Chem. 535 (1997)
129.
[27] P.K. Baker, M.A. Beckett, M.G.B. Drew, S.C.M.C. Godhino,
N. Robertson, A.E. Underhill, Inorg. Chim. Acta 279 (1998) 65.
[28] P.K. Baker, M.G.B. Drew, M.M. Meehan, H.K. Patel, A.
White, J. Chem. Res.(S) (1998) 379; J. Chem. Res. (M) (1998)
1461.
[29] N.G. Aimeloglou, P.K. Baker, M.M. Meehan, M.G.B. Drew,
Polyhedron 17 (1998) 3455.
[30] M. Al-Jahdali, P.K. Baker, M.G.B. Drew, Z. Naturforsch. Sect.
B 54 (1999) 171.
Acknowledgements
[31] P.K. Baker, E.M. Armstrong, M.G.B. Drew, Inorg. Chem. 28
(1989) 2406.
M. Al-Jahdali thanks the Saudi Arabian Government
for supporting him on a PhD studentship. We also
thank A.W. Johans for his assistance with the crystallo-
graphic investigation, and the EPSRC and the Univer-
sity of Reading for funds for the image plate system.
[32] P.K. Baker, M.G.B. Drew, D.S. Evans, A.W. Johans, M.M.
Meehan, J. Chem. Soc., Dalton Trans. (1999) 2541.
[33] S.R. Allen, P.K. Baker, S.G. Barnes, M. Green, L. Trollope, L.
Manojiovic-Muir, K.W. Muir, J. Chem. Soc., Dalton Trans.
(1981) 873.
[34] R.S. Herrick, D.M. Leazer, J.L. Templeton, Organometallics 2
(1983) 834.
[35] J.L. Templeton, B.C. Ward, J. Am. Chem. Soc. 102 (1980) 3288.
[36] E.M. Armstrong, P.K. Baker, M.G.B. Drew, Organometallics 7
(1988) 319.
[37] P.K. Baker, E.M. Armstrong, M.G.B. Drew, Inorg. Chem. 27
(1988) 2287.
References
[1] J.L. Templeton, Adv. Organomet. Chem. 29 (1989) 1 and refer-
ences cited therein.
[2] P.K. Baker, Adv. Organomet. Chem. 40 (1996) 45 and references
cited therein.
[38] P.K. Baker, Chem. Soc. Rev. 27 (1998) 125 and references cited
therein.
[3] P. Umland, H. Vahrenkamp, Chem. Ber. 115 (1982) 3580.
[4] J.L. Davidson, G. Vasapollo, J. Chem. Soc., Dalton Trans.
(1985) 2239.
[5] M.A. Bennett, I.W. Boyd, J. Organomet. Chem. 290 (1985) 165.
[6] P.B. Winston, S.J.N. Burgmayer, T.L. Tonker, J.L. Templeton,
Organometallics 5 (1986) 107.
[39] E.M. Armstrong, P.K. Baker, M.G.B. Drew, J. Organomet.
Chem. 336 (1987) 377.
[40] P.K. Baker, M.G.B. Drew, S. Edge, S.D. Ridyard, J.
Organomet. Chem. 409 (1991) 207.
[41] M. Al-Jahdali, P.K. Baker, M.M. Meehan, Unpublished results.
[42] R.S. Herrick, J.L. Templeton, Organometallics 1 (1982) 842.
[43] J.R. Morrow, T.L. Tonker, J.L. Templeton, J. Am. Chem. Soc.
107 (1985) 5004.
[7] A.K. List, G.L. Hillhouse, A.L. Rheingold, J. Am. Chem. Soc.
110 (1988) 4855.
[8] E.M. Armstrong, P.K. Baker, S.G. Fraser, J. Chem. Res. (S)
(1988) 52; J. Chem. Res. (M) 0410.
[44] E.M. Armstrong, P.K. Baker, K.R. Flower, M.G.B. Drew, J.
Chem. Soc., Dalton Trans. (1990) 2535.
[9] E.M. Armstrong, P.K. Baker, J. Organomet. Chem. 352 (1988)
133.
[10] E.M. Armstrong, P.K. Baker, M.E. Harman, M.B. Hursthouse,
J. Chem. Soc., Dalton Trans. (1989) 295.
[45] C.A. Tolman, Chem. Rev. 77 (1977) 313.
[46] W. Kabsch, J. Appl. Cryst. 21 (1988) 916.
[47] G.M. Sheldrick, Acta Cryst. A46 (1990) 467.
[48] N. Walker, D. Stuart, Acta Cryst. A39 (1983) 158.
[49] G.M. Sheldrick, SHELXL 1993 Program for Crystal Structure
Refinement, University of Go¨ttingen.
[11] B.J. Brisdon, A.G.W. Hodson, M.F. Mahon, K.C. Molloy, R.A.
Walton, Inorg. Chem. 29 (1990) 2701.
.