The reactions of the monodentate organometallic phosphines [MI2(CO)3{MeC(CH2 PPh2)3-P,P′}] (M = Mo, W) with π-allyl molybdenum(II) complexes and iron(O) and iron(II) carbonyl complexes

Article abstract of DOI:10.1016/S0277-5387(02)01164-6

Equimolar quantities of [MoX(CO)₂(NCMe)₂ (η³-C₃H₄R)] (X = Cl, R = H or Me; X = Br, R = H) and [MI₂(CO)₃- {MeC(CH₂PPh₂)₃-P,P′}] (M = Mo or W) reac

Full text of DOI:10.1016/S0277-5387(02)01164-6

Polyhedron 21 (2002) 2301ꢁ2308
/
www.elsevier.com/locate/poly
The reactions of the monodentate organometallic phosphines
[MI2(CO)3{MeC(CH2PPh2)3-P,P?}] (Mꢀ
molybdenum(II) complexes and iron(O) and iron(II) carbonyl
/
Mo, W) with p-allyl
complexes
Paul K. Baker *, Mutlaq Al-Jahdali
Department of Chemistry, University of Wales, Bangor, Gwynedd LL57 2UW, Wales, UK
Received 17 May 2002; accepted 18 July 2002
Abstract
Equimolar quantities of [MoX(CO)2(NCMe)2(h3-C3H4R)] (Xꢀ
{MeC(CH2PPh2)3-P,P?}] (MꢀMo or W) react in CH2Cl2 at room temperature to eventually give the tetrametallic complexes,
[{Mo(m-X)(CO)2(LMo or LW)(h3-C3H4R)}2] {LMoꢀ[MoI2(CO)3{MeC(CH2PPh2)3-P,P?}]; LWꢀ
[WI2(CO)3{MeC(CH2PPh2)3-
P,P?}]} (1ꢁ Cl, RꢀH or Me; XꢀBr, RꢀH) with 2 equiv.
6) in good yield. Reaction of [MoX(CO)2(NCMe)2(h3-C3H4R)] (Xꢀ
of LMo or LW affords the trimetallic complexes [MoX(CO)2(LMo or LW)2(h3-C3H4R)] (7ꢁ
12). Treatment of [Fe2(CO)9] with 2 equiv.
of LMo or LW in CH2Cl2 at room temperature yields the bimetallic complexes, [Fe(CO)4(LMo or LW)] (13 and 14). Equimolar
amounts of [FeI(CO)2(Cp or Cp?)] (CpꢀC5H5; Cp?ꢀ
C5H4Me) and LMo or LW react in warm CH2Cl2 to give the cationic bimetallic
18). The cationic nature of these complexes was established by reacting
/
Cl, Rꢀ
/H
or Me; Xꢀ
/
Br, Rꢀ/H) and [MI2(CO)3-
/
/
/
/
/
/
/
/
/
/
/
complexes, [Fe(CO)2(LMo or LW)(Cp or Cp?)]I (15ꢁ
/
equimolar amounts of [Fe(CO)2LWCp]I with Na[BPh4] in CH2Cl2 to give the anion-exchanged product, [Fe(CO)2LWCp][BPh4] (19).
# 2002 Elsevier Science Ltd. All rights reserved.
Keywords: Organometallic phosphine; Multimetallic; p-Allyl molybdenum; Iron carbonyl complexes; Cyclopentadienyl iron complexes
1. Introduction
complexes react with a wide range of ligands to give a
variety of new organometallic complexes [25,26]. We
have also described the synthesis and characterization of
a range of new organometallic phosphine ligands,
[WI2(CO)3{PhP(CH2CH2PPh2)2-P,P?}] [27], [WI2(CO)-
Bimetallic and multimetallic phosphine-bridged tran-
sition-metal complexes have received considerable atten-
tion over the years. Although a wide range of bimetallic
phosphine-bridged complexes containing bidentate
phosphines such as bis(diphenylphosphino)methane as
the bridging ligand have been described [1ꢁ
complexes containing tridentate phosphines as bridging
ligands have been reported [12ꢁ23]. In 1986 [24], we
{PhP(CH2CH2PPh2)2-P,P?}(h2-RC2R?)] (Rꢀ
/
R?ꢀ
Ph) [28] and [MXY(CO){PhP-
(CH2CH2PPh2)2-P,P?}(h2-RC2R)] (Mꢀ
Mo or W; X,
YꢀCl, Br, I; RꢀMe or Ph) [29]. Very recently [30], we
/Me
or Ph; Rꢀ
/
Me, R?ꢀ
/
/
11], far fewer
/
/
/
/
have described the synthesis and characterization of the
tripodal triphos {MeC(CH2PPh2)3} monodentate phos-
described the synthesis and characterization of the
highly versatile seven-coordinate complexes, [MX2-
(CO)3(NCMe)2] (Mꢀ
phines, [MI2(CO)3{MeC(CH2PPh2)3-P,P?}] (MꢀMo
/
/
Mo or W; XꢀBr or I). These
/
or W). In this paper, we describe the reactions of
[MI2(CO)3{MeC(CH2PPh2)3-P,P?}] with the p-allyl
molybdenum complexes, [MoX(CO)2(NCMe)2(h3-
C3H4R)] (Xꢀ
[Fe2(CO)9] and [FeI(CO)2(Cp or Cp?)] (Cpꢀ
Cp?ꢀC5H4Me).
/
Cl, Rꢀ
/
H or Me; Xꢀ
/
Br, Rꢀ
/
H),
* Corresponding author. Tel.: ꢂ
370-528
E-mail address: chs018@bangor.ac.uk (P.K. Baker).
/
44-1248-382-379; fax: ꢂ44-1248-
/
/
C5H5;
/
0277-5387/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved.
PII: S 0 2 7 7 - 5 3 8 7 ( 0 2 ) 0 1 1 6 4 - 6

2302
P.K. Baker, M. Al-Jahdali / Polyhedron 21 (2002) 2301ꢁ2308
/
2. Experimental
Table 1
a
b
Physical and analytical data for the multimetallic complexes 1ꢁ
/
19
2.1. General procedures
1
[{Mo(m-Cl)(CO)2(LMo)(h3-
C3H5)}2]×CH2Cl2
54 43.5 (43.8) 3.6 (3.4)
2
3
[{Mo(m-Cl)(CO)2(LW)(h3-C3H5)}2]
[{Mo(m-Cl)(CO)2(LMo)(h3-C3H4Me-
2)}2]
54 42.8 (42.8) 3.6 (3.2)
28 46.5 (46.2) 3.8 (3.6)
All the reagents used in this research were purchased
from commercial sources and used as they were
required. The starting materials used in this research
4
[{Mo(m-Cl)(CO)2(LW)(h3-C3H4CH3-
2)}2]
21 43.1 (43.2) 3.6 (3.3)
namely, [MI2(CO)3{MeC(CH2PPh2)3-P,P?}] (Mꢀ
or W) [30], [MoX(CO)2(NCMe)2(h3-C3H4R)] (Xꢀ
RꢀH or Me; XꢀBr, RꢀH) [31] and [FeI(CO)2(Cp or
Cp?)] (CpꢀC5H5; Cp?ꢀC5H5Me) [32] were prepared
by published procedures.
/
Mo
[{Mo(m-Br)(CO)2(LMo)(h3-C3H5)}2]
[{Mo(m-Br)(CO)2(LW)(h3-C3H5)}2]
[MoCl(CO)2(LMo)2(h3-C3H5)]
[MoCl(CO)2(LW)2(h3-C3H5)]
[MoCl(CO)2(LMo)2(h3-C3H4Me-2)]
22 44.3 (44.2) 3.7 (3.3)
50 41.8 (41.5) 3.5 (3.1)
64 47.2 (47.6) 4.2 (3.6)
49 44.2 (44.3) 3.6 (3.3)
75 48.5 (47.9) 4.1 (3.6)
39 44.7 (44.5) 3.6 (3.4)
48 47.8 (47.3) 3.9 (3.8)
45 45.8 (44.9) 4.5 (3.2)
48 47.3 (46.7) 3.7 (4.1)
32 45.4 (45.0) 3.8 (3.3)
55 42.4 (42.2) 3.3 (3.1)
37 44.7 (45.3) 3.5 (3.4)
30 42.3 (42.6) 3.3 (3.2)
35 54.3 (54.8) 5.7 (3.9)
/
Cl,
5
6
7
8
9
/
/
/
/
/
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
10 [MoCl(CO)2(LW)2(h3-C3H4Me-2)]
11 [MoBr(CO)2(LMo)2(h3-C3H5)]×Et2O
13 [Fe(CO)4(LMo)]×CH2Cl2
14 [Fe(CO)4(LW)]
obtained using a PerkinꢁElmer 1600 series FT IR
/
15 [Fe(CO)2(LMo)Cp]I
spectrophotometer. 1H and 31P{1H} spectra were re-
corded on a Bruker AC250 MHz NMR spectrometer;
1H NMR spectra were referenced to SiMe4, 31P{1H}
NMR spectra were referenced to 85% H3PO4. Molecular
weight measurements were made using Rast’s method
[33], using camphor as the standard.
16 [Fe(CO)2(LW)Cp]I
17 [Fe(CO)2(LMo)Cp?]I
18 [Fe(CO)2(LW)Cp?]I
19 [Fe(CO)2(LW)Cp][BPh4]
a
All complexes 1 to 19 are green.
Calculated values in parenthesis.
b
2.2. [{Mo(m-Cl)(CO)2(LMo)(h3-C3H5)}2] (1)
LW)2(h3-C3H4R)] {Xꢀ
/
Cl, Rꢀ
/
H, LW (8); RꢀMe, LMo
/
(9); LW (10)}; {Xꢀ
physical and analytical data see Table 1.
/
Br, Rꢀ
/
H, LMo (11), LW (12)}. For
To a stirred solution of [MoCl(CO)2(NCMe)2(h3-
C3H5)] (0.08 g, 0.32 mmol) in CH2Cl2 (25 cm3) was
added [MoI2(CO)3{MeC(CH2PPh2)3-P,P?}](LMo) (0.3
g, 0.26 mmol). Filtration and removal of solvent in
vacuo after 24 h, gave the green crystalline powder
[{Mo(m-Cl)(CO)2(LMo)(h3-C3H5)}2] (1), which was re-
2.4. [Fe(CO)4(LMo)] (13)
To a stirred solution of [Fe2(CO)9] (0.05 g, 0.13 mmol)
in CH2Cl2 (25 cm3) was added [MoI2(CO)3{MeC-
(CH2PPh2)3-P,P?}] (0.3 g, 0.28 mmol). Filtration and
removal of solvent in vacuo after 24 h, gave the green
powder [Fe(CO)4(LMo)] (13), which was recrystallized
crystallized from CH2Cl2ꢁ
pure productꢀ0.22 g (54%).
Similar reactions of [MoX(CO)2(NCMe)2(h3-
C3H4R)] (Xꢀ
Cl and Br) with 1 equiv. of LMo or LW
{LMo or LWꢀ
[MI2(CO)3{MeC(CH2PPh2)3-P,P?}] in
CH2Cl2 at room temperature (r.t.) gave the complexes
[{Mo(m-X)(CO)2(LMo or LW)(h3-C3H4R)}2] {Xꢀ
Cl,
Rꢀ Br,
H, LW (2); RꢀMe, LMo (3); LW (4)}; {Xꢀ
Rꢀ
H, LMo (5), LW (6)}. For physical and analytical
/
Et2O at ꢃ
/
17 8C. Yield of
/
/
from CH2Cl2ꢁ
/
Et2O at ꢃ
/
17oC. Yield of pure productꢀ
/
/
0.08 g (45%).
A similar reaction of [Fe2(CO)9] with 2 equiv. of LW
in CH2Cl2 at r.t. gave the complex, [Fe(CO)4(LW)] (14).
For physical and analytical data see Table 1.
/
/
/
/
/
data see Table 1.
2.5. [Fe(CO)2(LMo)(Cp]I (15)
2.3. [MoCl(CO)2(LMo)2(h3-C3H5)] (7)
To a stirred solution of [FeI(CO)2(h5-C5H5)] (0.05 g,
0.16 mmol) in warm CH2Cl2 (25 cm3) was added
[MoI2(CO)3{MeC(CH2PPh2)3-P,P?}] (0.17 g, 0.16
mmol). Filtration and removal of solvent in vacuo after
2 h gave [Fe(CO)2(LMo)(h5-C5H5)]I (15), which was
To a stirred solution of [MoCl(CO)2(NCMe)2(h3-
C3H5)] (0.05 g, 0.16 mmol) in CH2Cl2 (25 cm3) was
added [MoI2(CO)3{MeC(CH2PPh2)3-P,P?}] (0.34 g,
0.32 mmol). Filtration and removal of solvent in vacuo
after 24 h, gave the green crystalline powder
[MoCl(CO)2(LMo)2(h3-C3H5)] (7), which was recrystal-
recrystallized from CH2Cl2ꢁ
productꢀ0.07 g (32%).
A similar reaction of [FeI(CO)2(h5-C5H4R)] (Rꢀ
or Me) with 1 equiv. of L {Lꢀ[MI2(CO)3{MeC-
(CH2PPh2)3-P,P?}] (MꢀMo or W)} in warm CH2Cl2
at r.t. gave the complexes [Fe(CO)2(LMo or LW)(h5-
C5H4R)]I, {Rꢀ
H, LW (16); RꢀMe, LMo (17), LW
(18)}. For physical and analytical data see Table 1.
/Et2O. Yield of pure
/
lized from CH2Cl2ꢁ
productꢀ0.24 g (64%).
Similar reactions of [MoX(CO)2(NCMe)2(h3-
C3H4R)] (Xꢀ
Cl and Br) with 2 equiv. of LMo or LW
{LMo or LWꢀ
[MI2(CO)3{MeC(CH2PPh2)3-P,P?}]} in
CH2Cl2 at r.t. gave the complexes, [MoX(CO)2 (LMo or
/
Et2O at ꢃ
/
17 8C. Yield of pure
/H
/
/
/
/
/
/
/

P.K. Baker, M. Al-Jahdali / Polyhedron 21 (2002) 2301ꢁ
/
2308
2303
2.6. [Fe(CO)2(LW)(h5-C5H5)][BPh4] (19)
Table 2
Infrared data for the multimetallic complexes 1ꢁ
a
/
19
To a stirred solution of [Fe(CO)2(LW)(h5-C5H5)]I
(0.05 g, 0.43 mmol) in CH2Cl2 (25 cm3) was added
Na[BPh4] (0.012 g, 0.42 mmol). Filtration and removal
of solvent in vacuo after 24 h, gave the green complex,
[Fe(CO)2(LW)(h5-C5H5)][BPh4] (19), which was recrys-
Complex
n(CÅO) (cmꢃ1
)
1
2
2015(s), 1941(s), 1933(br,s), 1842(m)
2031(s), 1956(br,s), 1938(s), 1901(m)
2040(s), 1981(s), 1938(br,s), 1846(m)
3
4
2036(s), 1957(br,s), 1935(s), 1904(s), 1844(m)
2021(s), 1948(s), 1939(br,s), 1849(m)
2039(s), 1961(br,s), 1945(s), 1906(m)
2041(s), 1959(s), 1939(br,s), 1846(m)
2038(s), 1960(br,s), 1932(s), 1905(m)
2044(s), 1974(s), 1938(br,s), 1841(m)
2033(s), 1957(br,s), 1933(s), 1903(m), 1840(m)
2037(s), 1968(s), 1931(br,s), 1839(m)
2034(s), 1957(br,s), 1904(s), 1843(m)
2044(s), 2019(s), 1976(br,s), 1928(s), 1939(m)
2030(s), 1955(s), 1928(br,s), 1912(m), 1901(m)
2043(s), 2019(s), 1998(s), 1938(br,s), 1906(m)
2038(s), 1996(s), 1958(br,s), 1903(m)
2039(s), 1993(s), 1940(br,s), 1918(s), 1909(m)
2038(s), 1994(s), 1960(br,s), 1906(m)
2038(s), 2000(s), 1958(br,s), 1908(m)
tallized from CH2Cl2ꢁ
/
Et2O at ꢃ17 8C. Yield of pure
/
5
productꢀ0.02 g (35%).
/
6
7
8
9
3. Results and discussion
10
11
12
13
14
15
16
17
18
19
3.1. Preparation and characterization of the tetrametallic
complexes [{Mo(m-X)(CO)2(LMo or LW)(h3-
C3H4R)}2] (1ꢁ6)
/
The starting materials used in this research,
[MI2(CO)3{MeC(CH2PPh2)3-P,P?}] (MꢀMo or W)
/
were prepared by reacting the bis(acetonitrile) com-
plexes [MI2(CO)3(NCMe)2] [24], with 1 equiv. of tripo-
dal triphos, MeC(CH2PPh2)3, in CH2Cl2 for 15 min at
room temperature [30]. Equimolar amounts of
a
Spectra recorded in CHCl3 as thin films between NaCl plates. s,
strong; m, medium.
[MoX(CO)2(NCMe)2(h3-C3H4R)] (Xꢀ
Me; XꢀBr, RꢀH) and [MI2(CO)3{MeC(CH2PPh2)3-
P,P?}] (Mꢀ
Mo, LMo; MꢀW, LW) react in CH2Cl2 at
/
Cl, Rꢀ
/
H or
[MoI2(CO)3{MeC(CH2PPh2)3-P,P?}] part of the mole-
cule. The complex [MoI2(CO)3{MeC(CH2PPh2)3-P,P?}]
/
/
2041, 1938 and 1917 cmꢃ1
.
/
/
[30], has n(CO)(CHCl3)ꢀ
The molecular structures of several p-allyl complexes of
the type [MoX(CO)2L2(h3-allyl)] (L2ꢀ
nitrogen donor
ligands) have been crystallographically determined [34ꢁ
/
room temperature to eventually give the halo-bridged
and tripodal triphos-bridged tetrametallic complexes,
/
[{Mo(m-X)(CO)2(LMo or LW)(h3-C3H4R)}2] (1ꢁ
/
6) in
moderate yield, via displacement of both of the aceto-
nitrile ligands. All the complexes 1ꢁ6 were characterised
/
43], and all show a cis-carbonyl geometry in an
equivalent plane with the nitrogen donor ligands. The
axial sites have the halide and p-allyl groups. However,
the only monodentate bis(phosphorus) donor ligand p-
allyl complex of this type to be crystallographically
characterised is [MoCl(CO)2{P(OMe)3}2(h3-C3H5)] [44].
This complex has a distorted pentagonal bipyramidal
geometry, with a carbonyl ligand and a chloride group
in axial positions, and the p-allyl group occupying two
adjacent sites. In view of the IR carbonyl pattern for the
/
by elemental analysis (C, H and N) (Table 1), IR (Table
1
2), H and 31P{1H} NMR spectroscopy (Tables 3 and
4). Molecular weight measurements of selected com-
plexes were determined using Rast’s method [33]. These
measurements confirmed the tetrametallic nature of
these complexes. Complex 1 (Xꢀ
/
Cl, Rꢀ
H, LMo) was
confirmed as a CH2Cl2 solvate by repeated elemental
/
analyses and 1H NMR spectroscopy. The new com-
plexes 1ꢁ
stored under dinitrogen, but they all readily decompose
in solution when exposed to air. Complexes 1ꢁ6 are
/
6 are moderately stable in the solid-state when
complexes 1ꢁ
metry will be described for the mono(phosphine) com-
6, rather than the pentagonal bipyramidal
/6, it is likely the pseudo-octahedral geo-
/
plexes 1ꢁ
/
soluble in CHCl3 and CH2Cl2, but only slightly soluble
in diethyl ether.
geometry shown for [MoCl(CO)2{P(OMe)3}2(h3-C3H5)]
[44]. The two halides of the halo-bridged dimers are
identical, as only two cis-carbonyl groups were ob-
served.
The IR spectra of complexes 1ꢁ6 (Table 2) as
/
expected all show a number of carbonyl bands due to
both the [MI2(CO)3{MeC(CH2PPh2)3-P,P?}] unit, and
the p-allyl molybdenum fragment. For example, com-
plex 1 showed bands at 2015, 1941, 1933 and 1842
cmꢃ1. It is highly likely that the bands at 1933 and 1842
cmꢃ1 are due to the cis-carbonyl groups on the p-allyl
molybdenum part of the molecule. {The complex,
[MoCl(CO)2(NCMe)2(h3-C3H5)] has carbonyl bands at
The 31P{1H} NMR spectra (Table 4) show resonances
for the 2 equiv. phosphorus atoms attached to the
molybdenum and tungsten centres in the units,
[MI2(CO)3{MeC(CH2PPh2)3-P,P?}]. Tungsten satellites
were not observed, due to the poor solubility of the
complexes in a range of NMR solvents. For example,
the 31P{1H} NMR spectrum of 2 has a resonance at dꢀ
17.7 ppm (due to the fluxional seven-coordinate LW
fragment), and dꢀ27.3 ppm due to the phosphorus
/
n(CO)(CHCl3)ꢀ
1955 and 1848 cmꢃ1 [31].} The broad
/
band at 1933 cmꢃ1, together with the bands at 2015 and
ꢃ
/
1941 cmꢃ1 are very likely to be due to the
/

2304
P.K. Baker, M. Al-Jahdali / Polyhedron 21 (2002) 2301ꢁ2308
/
Table 3
Table 4
31P{1H} NMR data (d) for the multimetallic complexes 1ꢁ
18
a
a
1H NMR data (d) for the multimetallic complexes 1ꢁ
/19
/
Complex 1H NMR data (d/ppm)
Complex
31P data (d/ppm)
1
8.4ꢁ
/
7.5 (m, 60H, Ph); 5.3 (s, 2H, CH2Cl2); 3.6 (m, 2H, CH
1
2
17.6 (s, 4P, LMo); 31.8 (s, 2P, Ph2PÃMo)
ꢃ17.7 (s, 4P, LW); 27.3 (s, 2P, Ph2PÃMo)
17.6 (s, 4P, LMo); 29.0 (s, 2P, Ph2PÃMo)
ꢃ12.2 (s, 4P, LW); 32.0 (s, 2P, Ph2PÃMo)
17.6 (s, 4P, LMo); 34.6 (s, 2P, Ph2PÃMo)
ꢃ11.8 (s, 4P, LW); 25.0 (s, 2P, Ph2PÃMo)
17.6 (s, 4P, LMo); 32.9 (s, 2P, Ph2PÃMo)
ꢃ12.8 (s, 4P, LW); 25.3 (s, 2P, Ph2PÃMo)
17.6 (s, 4P, LMo); 29.5 (s, 2P, Ph2PÃMo)
ꢃ14.4 (s, 4P, LW); 25.1 (s, 2P, Ph2PÃMo)
17.6 (s, 4P, LMo); 27.5 (s, 2P, Ph2PÃMo)
ꢃ14.2 (s, 4P, LW); 25.1 (s, 2P, Ph2PÃMo)
17.6 (s, 2P, LMo); 27.9 (s, 1P, Ph2PÃFe)
ꢃ16.4 (s, 2P, LW); 39.3 (s, 1P, Ph2PÃFe)
17.6 (s, 2P, LMo); 52.7 (s, 1P, Ph2PÃFe)
ꢃ12.2 (s, 2P, LW); 52.7 (s, 1P, Ph2PÃFe)
17.6 (s, 2P, LMo); 52.3 (s, 1P, Ph2PÃFe)
ꢃ14.0 (s, 2P, LW); 52.0 (s, 1P, Ph2PÃFe)
of allyl); 2.2 (m, 8H, CH of allyl); 1.9 (m, 12H, CH2 of
triphos); 1.3 (s, 6H, CH3, triphos)
3
2
8.0ꢁ
8H, CH2 of allyl); 1.8ꢁ
6H, CH3 of triphos)
7.9ꢁ7.0 (m, 60H, Ph); 3.1 (m, 2H, CH, allyl); 2.4ꢁ
/
7.2 (m, 60H, Ph); 3.6 (m, 2H, CH of allyl); 2.5ꢁ
/2.2 (m,
4
/1.5 (m, 12H, CH2 of triphos); 1.3 (s,
5
6
3
/
/
2.2 (m,
7
6H, CH2, allyl); 1.5 (s, 6H, CH3, allyl); 1.4 (br,s, 12H, CH2,
triphos); 1.1 (s, 6H, CH3, triphos)
8
9
4
7.8ꢁ
(m, 6H, CH2, allyl); 1.6 (s, 6H, CH3, allyl); 1.7ꢁ
CH2, triphos); 1.2 (s, 6H, CH3, triphos)
7.8ꢁ7.1 (m, 60H, Ph); 3.7ꢁ3.5 (m, 2H, CH, allyl); 2.5ꢁ
(m, 8H, CH2, allyl); 1.8ꢁ1.4 (m, 12H, CH2, triphos); 1.3 (s,
6H, CH3, triphos)
7.8ꢁ7.2 (m, 60H, Ph); 3.8ꢁ
(m, 8H, CH2, allyl); 1.9ꢁ1.4 (m, 12H, CH2, triphos); 1.3 (s,
6H, CH3, triphos)
7.8ꢁ7.0 (m, 60H, Ph); 3.65 (m, 1H, CH, allyl); 2.3 (dd, 4H,
/
7.1 (m, 60H, Ph); 3.7ꢁ
/
3.4 (m, 2H, CH2, allyl); 2.5ꢁ
/2.1
10
11
12
13
14
15
16
17
18
/1.4 (m, 12H,
5
/
/
/2.2
/
6
/
/
3.6 (m, 2H, CH, allyl); 2.4ꢁ2.2
/
/
7
/
a
Spectra recorded in CDCl3 (ꢂ25 8C) and referenced to 85%
CH2, allyl); 2.0 (s, 12H, CH2, triphos); 1.3 (s, 6H, CH3,
triphos)
H3PO4.
8
8.1ꢁ
4H, CH2, allyl); 1.8ꢁ
CH3, triphos)
7.9ꢁ7.0 (m, 60H, Ph); 3.2 (m, 1H, CH, allyl); 2.6ꢁ
3H, CH2, allyl); 1.5 (s, 3H, CH3, allyl); 1.3 (s, 12H, CH2,
triphos); 0.9 (s, 6H, CH3, triphos)
/
7.1 (m, 60H, Ph); 3.5 (m, 1H, CH, allyl); 2.5ꢁ
/
2.2 (m,
2.2 (m,
phosphorus atom attached to the p-allyl molybdenum
6 is
shown in Fig. 1, which shows that the LMo or LW are
coordinated in a trans configuration to each other, with
a bulky phosphine group and p-allyl group trans to the
other one.
/1.5 (m, 12H, CH2, triphos); 1.3 (s, 6H,
moiety. The geometry of one isomer of complexes 1ꢁ
/
9
/
/
10
11
7.9ꢁ/7.0 (m, 60H, Ph); 3.7 (br,s, 1H, CH, allyl); 2.5ꢁ2.1 (m,
/
3H, CH2, allyl); 1.6 (m, 3H, CH3, allyl); 1.3 (br,s, 12H, CH2,
triphos); 0.9 (s, 6H, CH3, triphos)
Complexes 1ꢁ6 are most likely to be obtained from
/
the bimetallic complexes, [MoX(CO)2(NCMe)(LMo or
LW)(h3-C3H4R)], which could not be isolated even with
short reaction times, and the tetrametallic nature of the
products was confirmed by the lack of nitrogen in the
elemental analysis results and no acetonitrile resonances
observed in the 1H NMR spectra. Also molecular weight
studies using Rast’s method [33] confirmed the tetra-
7.8ꢁ/7.0 (m, 60H, Ph); 3.6 (br,s, 1H, CH, allyl); 3.5 (q, 4H,
CH2, diethyl ether); 2.5 (t, 6H, CH3, diethyl ether); 2.3ꢁ
(m, 15H, CH2, allyl, CH2 triphos); 1.6 (m, 3H, CH3, allyl);
0.9 (s, 6H, CH3, triphos)
/2.1
12
7.9ꢁ/7.1 (m, 60H, Ph); 3.8ꢁ/3.6 (m, 1H, CH, allyl); 2.6ꢁ2.2
/
(br.m, 15H, CH2, allyl, CH2, triphos); 1.3 (s, 6H, CH3,
triphos)
13
14
15
16
17
18
19
7.8ꢁ
CH2, triphos); 0.9 (s, 3H, CH3, triphos)
7.7ꢁ6.8 (m, 30H, Ph); 2.4 (br,s, 6H, CH2, triphos); 0.9 (s,
3H, CH3, triphos)
7.7ꢁ7.0 (m, 30H, Ph); 5.1 (s, 5H, Cp); 2.3 (s, 6H, CH2,
triphos); 0.9 (s, 3H, CH3, triphos)
7.7ꢁ7.2 (m, 30H, Ph); 5.1 (s, 5H, Cp); 2.7 (br,s, 6H, CH2,
triphos); 1.3 (s, 3H, CH3, triphos)
7.7ꢁ7.0 (m, 30H, Ph); 4.9 (d, 4H, Cp); 2.4 (br,s, 6H, CH2,
triphos); 2.2 (s, 3H, MeCp); 0.9 (s, 3H, CH3, triphos)
7.8ꢁ7.0 (m, 30H Ph); 4.9 (d, 4H, Cp); 2.5 (br,s, 6H, CH2,
triphos); 2.2 (s, 3H, MeCp); 0.9 (s, 3H, CH3, triphos)
7.9ꢁ7.1 (m, 50H, Ph); 5.1 (m, 5H, Cp); 2.3 (s, 6H, CH2,
/7.0 (m, 30H, Ph); 5.3 (s, 2H, CH2Cl2); 2.3 (br,s, 6H,
metallic nature of 1ꢁ6. Several unsuccessful attempts
/
/
were made to obtain FAB mass spectra of the com-
plexes, although fragment peaks were obtained the
parent ions could not be observed for these complexes.
/
/
3.2. Synthesis and characterization of the trimetallic
complexes, [MoX(CO)2(LMo or LW)2(h3-C3H4R)] (7ꢁ
12)
/
/
/
Reaction of [MoX(CO)2(NCMe)2(h3-C3H4R)] (Xꢀ
Cl, RꢀH or Me; XꢀBr, RꢀH) with 2 equiv. of
LMo or LW in CH2Cl2 at room temperature affords the
/
/
triphos); 0.9 (s, 3H, CH3, triphos)
/
/
/
a
Spectra recorded in CDCl3 (ꢂ25 8C) and referenced to SiMe4. s,
singlet; br, broad; d, doublet; m, multiplet; t, triplet.
trimetallic,
tripodal
triphos-bridged
complexes,
12) in moder-
[MoX(CO)2(LMo or LW)2(h3-C3H4R)] (7ꢁ
/
atoms attached to the p-allyl fragment in an approxi-
mately 2:1 intensity ratio. The assignments of reso-
nances in the 31P{1H} NMR spectra were due to the
expected resonances of the phosphine ligands,
[MI2(CO)3{MeC(CH2PPh2)3-P,P?}] [30], and the gen-
erally lower field and less intense resonance due to the
ate yield, by displacement of both of the acetonitrile
ligands. The complexes 7ꢁ12 have been fully charac-
terised by elemental analysis (C and H), (Table 1), IR
/
(Table 2), 1H and 31P{1H} NMR spectroscopy. The
complex [MoBr(CO)2(LMo)2(h3-C3H5)]×
confirmed as a diethyl ether solvate by repeated
/Et2O (11) was

P.K. Baker, M. Al-Jahdali / Polyhedron 21 (2002) 2301ꢁ
/
2308
2305
Fig. 1. Proposed structure of [{Mo(m-X)(CO)2(LMo or LW)(h3-C3H4R)}2] (Mꢀ
/
Mo or W) (1ꢁ6).
/
elemental analyses and 1H NMR spectroscopy. FAB
mass spectra were attempted without success, as no
parent ions were observed. However, molecular weight
studies by Rast’s method [33] suggest the trimetallic
nature of these complexes (see Table 5). Generally,
resonance due to the equivalent phosphine atoms
attached to the fluxional [MoI2(CO)3{MeC(CH2-
PPh2)3-P,P?}] units at dꢀ
dꢀ32.9 ppm is due to the 2 equiv. phosphorus atoms
attached to the molybdenum p-allyl unit. The intensity
ratio of the resonances at dꢀ17.6 and 32.9 ppm is
/
17.6 ppm. The resonance at
/
/
complexes 7ꢁ
the tetrametallic complexes 1ꢁ
plexes 7ꢁ12 have to be stored under dinitrogen in the
solid-state.
The IR spectra of the trimetallic complexes, 7ꢁ
/12 are more stable and less soluble than
approximately 2:1, which was expected. Although the
only crystal structure of a bis(monodentate) phosphorus
donor complex [MoCl(CO)2{P(OMe)3}2(h3-C3H5)] [44],
has a distorted pentagonal bipyramidal structure with
carbonyl and a chloro group in the axial position, the
two phosphite ligands are in different environments in
the equatorial plane. In view of the IR and 31P{1H}
NMR spectral data (Tables 2 and 4), it is more likely the
/6 described earlier. Com-
/
/12 are
all relatively simple and show the expected bands for the
p-allyl molybdenum cis-dicarbonyl unit, and the diiodo
tricarbonyl molybdenum and tungsten moieties. For
example, complex 7 has bands at n(CO)ꢀ2041, 1959,
/
structure of 7ꢁ12 has distorted pentagonal bipyramidal
/
1939 and 1846 cmꢃ1. It is very likely the bands at 1939
and 1846 cmꢃ1 are due to the cis-dicarbonyl p-allyl
unit, and the bands at 2041, 1959 and 1939 cmꢃ1 (and
probably a masked band due to MI2(CO)3 unit), are due
to the LMo part of the molecule. The room temperature
31P{1H} NMR spectrum for complex 7 shows a
arrangement with the two organometallic phosphine
units trans to each other, with the carbonyl groups,
chloro group and p-allyl unit occupying the five
equatorial sites, (the p-allyl group occupying two sites).
The proposed structure for 7ꢁ12 is shown in Fig. 2. The
/
structure of the seven-coordinate halocarbonyl part of
the molecule most likely has a distorted capped octahe-
dral structure as many structures of [MX2(CO)3L2] have
Table 5
Molecular weight studies using Rast’s method [33] for selected
multimetallic complexes
a
distorted capped octahedral geometries [25,26,45ꢁ47].
/
Complex
Molecular weight {Found (Calc.)}
3.3. Synthesis and characterization of the bimetallic
complexes, [Fe(CO)4(LMo or LW)] (13 and 14)
3
9
1429 (1300)
2667 (2358)
2667 (2534)
2222 (2389)
2667 (2565)
1333 (1282)
1429 (1370)
1429 (1362)
1482 (1450)
1333 (1376)
1379 (1464)
Reaction of [Fe2(CO)9] with 2 equiv. of LMo or LW in
CH2Cl2 at room temperature affords the bimetallic,
tripodal triphos-bridged complexes, [Fe(CO)4(LMo or
LW)] (13 and 14) in moderate yield. Complexes 13 and
14 have been characterised by elemental analysis (Table
10
11
12
13
14
15
16
17
18
1
1), IR (Table 2) and H and 31P{1H} NMR spectro-
scopy (Tables 3 and 4). Molecular weight studies by
Rast’s method [46] on both complexes (Table 5),
confirmed the bimetallic nature of these complexes.
a
Camphor was used as the solvent in these measurements.

2306
P.K. Baker, M. Al-Jahdali / Polyhedron 21 (2002) 2301ꢁ2308
/
carbonyl bands at n(CO)(Hexane)ꢀ2043, 1975 and
/
1947 cmꢃ1 [48]. Hence, the bands are similar for the
two complexes, which agrees with the broad overlapping
carbonyl region of the IR spectra of 13 and 14.
The 31P{1H} NMR spectra of 14 shows one signal due
to the fluxional [WI2(CO)3{MeC(CH2PPh2)3-P,P?}]
unit at dꢀ
/
ꢃ
/
16.4 ppm, and another signal at dꢀ39.3
/
ppm due to the phosphorus atom which is coordinated
to the iron centre, in an approximately 2:1 intensity
ratio. The X-ray crystal structures of the complexes
[Fe(CO)4L] {LꢀP(p-tolyl)3 [48] and PPh3 [49]} have
/
been reported, and both have a very similar trigonal
bipyramidal geometry, with the phosphine ligand in the
axial position. In view of these studies, and the IR and
31P{1H} NMR spectral data of complexes 13 and 14, the
most likely structure for 13 and 14 is shown in Fig. 3.
3.4. Synthesis and characterization of the cationic
bimetallic complexes, [Fe(CO)2(LMo or LW)(Cp or
Cp?)]X (15ꢁ19)
/
Equimolar quantities of [FeI(CO)2(Cp or Cp?)] and
LMo or LW react in warm CH2Cl2 to give the cationic
iodide displaced bimetallic complexes [Fe(CO)2(LMo or
LW)(Cp or Cp?)]I (15ꢁ
18) in moderate yield. The
/
cationic nature of these complexes was confirmed by
an iodide exchange reaction with Na[BPh4]. Reaction of
[Fe(CO)2(LW)Cp]I (16) with 1 equiv. of Na[BPh4] in
CH2Cl2 at room temperature furnished the iodide-
exchanged complex, [Fe(CO)2(LW)Cp][BPh4] (19) in
35% yield. The cationic complexes 15ꢁ
acterised in the normal manner (Tables 1ꢁ
15ꢁ19 are soluble in polar solvents such as CH2Cl2,
/19 were char-
/
5). Complexes
/
CHCl3 and acetone, but as expected completely inso-
luble in diethyl ether and hydrocarbon solvents. The
complexes are stable in the solid-state if stored under an
Fig. 2. Proposed structure of [MoX(CO)2(LMo or LW)2(h3-C3H4R)]
(Mꢀ
/
Mo or W) (7ꢁ12).
/
Complexes 13 and 14 are soluble in CH2Cl2, less soluble
in CHCl3, and only sparingly soluble in diethyl ether
and hydrocarbon solvents. The complexes are air-
sensitive in solution, but can be stored in the solid-state
under an inert atmosphere.
The IR spectra of 13 and 14 have as expected a
number of carbonyl bands, there are four carbonyl
ligands on the iron centre and three carbonyl groups on
the molybdenum or tungsten centres. For example,
complex 14 has carbonyl bands (CHCl3) at 2030, 1955,
1928, 1912 and 1901 cmꢃ1. It is likely the bands at 2030,
1955 and 1901 cmꢃ1 are due to the [WI2(CO)3{MeC-
(CH2PPh2)3-P,P?}] fragment [30], but for the [Fe(CO)4]
part of complex 14, may have three carbonyl bands at
2030, 1928 and 1912 cmꢃ1. It should be noted that the
tungsten phosphine ligand, [WI2(CO)3{MeC(CH2-
PPh2)3-P,P?}] has bands at n(CO)(CHCl3)ꢀ2036,
/
1958 and 1904 cmꢃ1 [30], and a related simple mono-
dentate phosphine complex, [Fe(CO)4{P(o-tolyl)3}] has
Fig. 3. Proposed structure of [Fe(CO)4(LMo or LW)] (Mꢀ
(13 and 14).
/
Mo or W)

P.K. Baker, M. Al-Jahdali / Polyhedron 21 (2002) 2301ꢁ
/
2308
2307
cmꢃ1 are due to LMo [30]. The 31P{1H} NMR spectra of
complexes 15ꢁ19 show two resonances, and suggest a
single isomer for the complexes in solution. For
example, complex 15 has a single resonance at dꢀ52.7
ppm due to [Ph2PÃFe] unit and at dꢀ
17.6 ppm for LMo
in an approximately 1:2 intensity ratio. The likely
structure of complexes 15ꢁ19 is as shown in Fig. 4. A
/
/
/
/
/
number of unsuccessful attempts were made to grow
suitable single crystals for X-ray crystallography of
complexes 15ꢁ19 is as shown in Fig. 4.
/
4. Conclusions
Fig. 4. Proposed structure of the cationic complexes, [Fe(CO)2(LMo or
LW)(Cp or Cp?)]X (Mꢀ
Mo or W) (15ꢁ19).
In conclusion, the preparation and characterization of
a range of new multimetallic complexes (nineteen)
containing bridging-tripodal triphos, attached with two
phosphorus atoms on [MI2(CO)3{MeC(CH2PPh2)3-
P,P?}], and one phosphorus atom attached to a
molybdenum(II) p-allyl unit, an iron(0) unit or an
iron(II) moiety. These results are summarised in Scheme
1.
/
/
inert atmosphere, but decompose in solution when
exposed to air.
The IR spectra of 15ꢁ19 show the overlapping
/
carbonyl bands expected for the cis-Fe(CO)2-units,
and the [MI2(CO)3] unit. For example, the IR spectrum
for [Fe(CO)2(LMo)Cp]I (15) has bands at n(CO)ꢀ
2043,
/
2019, 1998, 1938 and 1906 cmꢃ1. The two bands at 2043
and 1998 cmꢃ1 are similar to the closely related
monodentate phosphine complex, [Fe(CO)2(PPh3)Cp]I,
Acknowledgements
which has carbonyl stretching bands at n(CO)ꢀ
/
2045
and 1995 cmꢃ1 [50]. The bands at 2019, 1938 and 1906
M. Al-Jahdali thanks the Saudi Arabian government
for supporting him on a PhD studentship.
Scheme 1. Reactions of LMo and LW with [MoX(CO)2(NCMe)2(h3-C3H4R)], [Fe2(CO)9] or [FeI(CO)2(Cp or Cp?)].

2308
P.K. Baker, M. Al-Jahdali / Polyhedron 21 (2002) 2301ꢁ2308
/
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