Synthesis and structure of diphenylphosphine derivatives of molybdenocene

Article abstract of DOI:10.1016/j.poly.2004.02.010

The phosphino molybdenocene complex [Cp₂Mo(PPh ₂H)₂][BF₄]₂ (1) (Cp = η⁵-C₅H₅) was prepared by reaction of Cp₂MoI₂ with PPh₂H and excess of TlBF ₄ in NCMe. The monocation [Cp₂MoI(PPh₂H)] ⁺ (2) as the BF₄^- or I^- salt was synthesised by treatment of Cp₂MoI(SPh) with HBF₄ followed by addition of PPh₂H, or by reaction of Cp₂MoI ₂ with PPh₂H, respectively. The indenyl phosphine complex [IndMo(CO)₂(PPh₂H)₂]BF₄ (3) (Ind = η⁵-C₉H₇) was prepared by reaction of IndMo(CO)₂(η³-C₃H₅) with HBF₄ followed by addition of PPh₂H. Deprotonation of 1 with dabco led to the formation of the phosphinophosphido molybdenocene [Cp ₂Mo(PPh₂)(PPh₂H)][BF₄] (4). Treatment of 1 with two equivalents of LiBu in thf at -30°C formed a thermally unstable complex (5) which could not be isolated. ³¹P NMR and protonation to reform 1 support its formulation as CpMo(PPh ₂)₂. The molecular structures of [Cp ₂Mo(PPh₂H)₂][BF₄]₂ and [Cp₂MoI(PPh₂H)]⁺ have been determined by single-crystal X-ray diffraction.

Full text of DOI:10.1016/j.poly.2004.02.010

Polyhedron 23 (2004) 1263–1270
www.elsevier.com/locate/poly
Synthesis and structure of diphenylphosphine derivatives
of molybdenocene
a
Sofia S.M.C. Godinho , Beatriz Royo , Maria T. Lobato , Eberhardt Herdtweck ,
a
b
c
a,
*
~
Carlos C. Romao
a
ꢀ
ꢀ
^
Instituto de Tecnologia Quımica e Biologica da Universidade Nova de Lisboa, Quinta do Marques, EAN, Apt 127, 2781-901 Oeiras, Portugal
b
Escola Secundꢀaria Fernando Lopes Graßca, Av. Comandante Gilberto Duarte, no. 470, 2775-200 Parede, Portugal
Anorganisch-chemisches Institut der Technischen Universit€at M€unchen, Lichtenbergstraße 4, D-85747 Garching bei M€unchen, Germany
c
Received 21 November 2003; accepted 9 February 2004
Abstract
The phosphino molybdenocene complex [Cp2Mo(PPh2H)2][BF4]2 (1) (Cp ¼ g5-C5H5) was prepared by reaction of Cp2MoI2
with PPh2H and excess of TlBF4 in NCMe. The monocation [Cp2MoI(PPh2H)]þ (2) as the BF4ꢀ or Iꢀ salt was synthesised by
treatment of Cp2MoI(SPh) with HBF4 followed by addition of PPh2H, or by reaction of Cp2MoI2 with PPh2H, respectively. The
indenyl phosphine complex [IndMo(CO)2(PPh2H)2]BF4 (3) (Ind ¼ g5-C9H7) was prepared by reaction of IndMo(CO)2(g3-C3H5)
with HBF4 followed by addition of PPh2H. Deprotonation of 1 with dabco led to the formation of the phosphinophosphido
molybdenocene [Cp2Mo(PPh2)(PPh2H)][BF4] (4). Treatment of 1 with two equivalents of LiBu in thf at )30 °C formed a thermally
unstable complex (5) which could not be isolated. 31P NMR and protonation to reform 1 support its formulation as CpMo(PPh2)2.
The molecular structures of [Cp2Mo(PPh2H)2][BF4]2 and [Cp2MoI(PPh2H)]þ have been determined by single-crystal X-ray
diffraction.
Ó 2004 Elsevier Ltd. All rights reserved.
Keywords: Cyclopentadienyl; Indenyl; Phosphino; Phosphido; Molybdenum; Metallocenes
1. Introduction
5 and 6 complexes are obtained by deprotonation of
Cp2ML(PPh2H)]þ (M ¼ Nb, Ta) or [Cp2MH(PPh2H)]þ
(M ¼ Mo, W). In turn, the PPh2H cations were obtained
by reaction of PPh2Cl with Cp2MLH (M ¼ Nb, Ta) [7]
and Cp2MH2 (M ¼ Mo, W) [6] respectively. The search
for bis-phosphido derivatives of the Cp2Nb fragment
was carried out by reaction of Cp02NbH(PPh2H) with
PR2Cl (R ¼ Me, [8] Ph [9]) that leads to the cations [Cp02
Nb(PPh2H)2]þ (Cp0 ¼ MeCp) [9] and [Cp2Nb(PPh2H)
PMe2H)]þ [8]. Deprotonation of these cations forms
Cp2Nb(PPh2)(PMe2H) [8], Cp02Nb(PPh2H)(PPh2) and
[Cp02Nb(PPh2)2]M0 (M0 ¼ Li, Na) [9]. The latter prod-
uct is more stable as the Na salt the Li salt decomposing
readily at room temperature.
Following the pioneering studies of Green and co-
workers on the synthesis of polynuclear complexes de-
rived from organometallic ligands, namely of type
Cp2M(l-SR)2M0Ln (M ¼ Mo, W, Nb; M0Ln several
transition metal fragments) [1], the related bis-phosphido
derivatives Cp2M(l-PR2)2M0Ln (M ¼ Zr, Hf) were first
reported simultaneously by three groups in 1985 [2–4].
Extension of this work to the metallocenes of group 5
led to the synthesis of Cp2ML(PPh2) (M ¼ Nb, Ta; L ¼
CO, PMe2Ph, P(OMe)3) and its PPh2 bridged adduct
with Cr(CO)5 [5]. The corresponding Mo and W com-
plexes of formula Cp2MH(PPh2) and their adducts with
CpMn(CO)2 were reported in 1990 [6]. Both these groups
The co-ordination chemistry of Cp2Nb(PPh2)(PMe2H)
was briefly examined [10].
The recent report on the synthesis and the crystal
structure of Cp2Nb(PPh2H)(PPh2) includes a large lit-
erature coverage of this topic [11].
* Corresponding author. Tel.: +351-214418407; fax: +351-
214411277.
~
E-mail address: ccr@itqb.unl.pt (C.C. Romao).
0277-5387/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2004.02.010

1264
S.S.M.C. Godinho et al. / Polyhedron 23 (2004) 1263–1270
In the present work we report our findings on the
synthesis and chemistry of molybdenocene derivatives of
PPh2H and our attempts to prepare the corresponding
phosphido indenyl analogues.
I
I
HBF4
[BF4]
Mo
Mo
PPh2H
SPh
PPh2H
2
2. Results and discussion
Scheme 2. Synthesis of [Cp2MoI(PPh2H)][BF4].
2.1. Synthesis of cationic complexes containing the
phosphine ligand PPh2H
having in mind the similar chemistry of both Cp2Mo
and IndCpMo fragments [16]. On the other hand,
reaction of PPh2H with the species formed in situ by
addition of one equivalent of HBF4 on IndMo(CO)2(g3-
C3H5), gave a moderate yield of a yellow compound
formulated as [IndMo(CO)2(PPh2H)2]BF4 (3) by means
Refluxing a solution of Cp2MoI2 with PPh2H in
NCMe in the presence of excess TlBF4, followed by
filtration of TlI and recrystallisation of the remaining
residue from NCMe/Et2O, gave orange–yellow crystals
of [Cp2Mo(PPh2H)2][BF4]2 (1) in ꢁ72% yield (see
Scheme 3). The 31P NMR spectrum of 1 shows only one
1
of IR and NMR spectroscopy. The H NMR spectrum
1
of 3 is consistent with the presence of a pentahapto in-
denyl ring as observed in similar examples with other
phosphines. The P–H protons appear at d 7.27 ppm
doublet at d 20.45 ppm (JP–H ¼ 396.0 Hz, P–H). Its H
NMR spectrum shows a doublet at d 7.60 ppm (JP–H
¼
396.0 Hz, P–H) assigned to the P–H proton of the
phosphine ligands. The resonance of the Cp protons
appears in the region usually observed for other dica-
tions of type [Cp2Mo(PR3)2]2þ [12], a triplet at d 5.99
ppm. The coupling of the Cp protons with the two
equivalent P atoms is very small, 2 Hz.
1
(JP–H ¼ 392.7 Hz) in the H NMR spectrum. Accord-
ingly, the 31P NMR spectrum shows only one doublet at
d 34.55 ppm (JP–H ¼ 393.6 Hz). The IR spectrum shows
the two strong vibrations of the cis-CO ligands in the
region expected for a Mo(II) complex with this charge
and structure. In spite of the lack of X-ray diffraction
data, the spectroscopic data are consistent with the gi-
ven formulation that corresponds to a very wide variety
of indenyl containing piano stool complexes.
In the absence of TlBF4 the above reaction mixture
produced a modest yield (24%) of the red complex
[Cp2MoI(PPh2H)]I (2, I) (see Scheme 1). This com-
pound was best prepared as the BF4 salt by reaction of
PPh2H with the reaction mixture obtained by treatment
of Cp2MoI(SPh) [13] with 1 equivalent of HBF4 in Et2O
(see Scheme 2). Under these conditions a good yield of
[Cp2MoI(PPh2H)]BF4 (2, BF4) was obtained. The 31P
NMR spectra of both salts of 2 in dichloromethane
show one doublet slightly shielded compared to that of
1, with slightly different chemical shifts for each anion.
2.2. Crystallography studies
The molecular structures of 1 and 2 have been de-
termined by X-ray diffraction. Their cationic moieties
are shown in Figs. 1 and 2, respectively. Bond lengths
and bond angles are listed in Table 1. A search in the
Cambridge Structural Database revealed five MoIV
compounds in addition with the same Mo-core geome-
1
As expected, the resonance of the Cp protons in the H
NMR spectrum reveals a higher shielding (ꢁ0.5 ppm) as
compared to that of 1. The crystal structure of the BF4ꢀ
salt of 2 was also solved by X-ray diffraction (see below).
Starting from IndCpMoX2 (X ¼ Cl, I), we were
unable to prepare any of the indenyl containing ana-
logues of both 1 and 2. Highly coloured dichroic prod-
ucts containing both PPh2H and indenyl were observed
1
by H and 31P NMR but the syntheses were totally ir-
reproducible. This is a surprising and unexplained result
I
I
PPh2H
[Ι]
Mo
Mo
I
PPh2H
Fig. 1. ORTEP style plot of the di-cationic part of 1 in the solid state.
Thermal ellipsoids are drawn at the 50% probability level. Hydrogen
atoms are omitted for clarity.
2
Scheme 1. Synthesis of [Cp2MoI(PPh2H)][I].

S.S.M.C. Godinho et al. / Polyhedron 23 (2004) 1263–1270
1265
2.3. Reactivity studies on the PPh2H complexes 1–3
The cationic nature of the complexes 1–3 suggests
facile deprotonation of the PPh2H ligands with forma-
tion of phosphido complexes, much in the same way as
has been reported for the Nb complexes mentioned
above. Indeed, treatment of a suspension of 1 in CH2Cl2
with excess NEt3 gives a bright orange solution. Con-
centration and addition of Et2O gives an orange crys-
talline product formulated as [Cp2Mo(PPh2)(PPh2H)]
BF4 (4). The same product is, however, best prepared
using dabco (1,4-diazabicyclo[2.2.2]octane) instead of
NEt3 since the protonated form of dabco precipitates
out and allows an easier purification of the product (see
Scheme 3). Treatment of a CH2Cl2 solution of 4 with
HBF4 in Et2O immediately precipitates the yellow di-
cation 1, as ascertained by 31P and H NMR. The H
NMR of 4 in CD2Cl2 at room temperature shows a set
of signals between d 7.60 and 7.10 ppm and one signal at
d 4.96 ppm assigned to the Cp protons. The 31P NMR in
the same solvent shows two resonances: a doublet at d
41.1 ppm (JP–H ¼ 364 Hz) and a singlet at d )11.9 ppm.
The former signal is assigned to the Ph2PH ligand and
the latter to the PPh2 ligand. A similar upfield resonance
of the P atom was found in Cp2MoH(PPh2) at d )10.3
ppm [2]. In the isoelectronic Nb complex, Cp2Nb(PPh2)
(HPPh2) two P resonances are found at d 66.2 and 5.9
ppm [11]. The proton resonance of the Ph2P–H ligand is
certainly hidden under the other aromatic signals, like in
Cp2Nb(PPh2)(HPPh2). A value of d 7.60 ppm is given
for the complex [Cp2Nb(PPh2H)(PMe2H)]Cl [8]. The 1H
NMR spectrum remains essentially unchanged on low-
ering the temperature down to 185 K.
1
1
Fig. 2. ORTEP style plot of the mono-cationic part of 2 in the solid
state. Thermal ellipsoids are drawn at the 50% probability level. Hy-
drogen atoms are omitted for clarity.
t
try Mo(g5-C5H4R)2E2 with R ¼ H, but and one E ¼
PR03 [14]. The results are given in Table 1, too. As ex-
pected from the NMR and IR data all three Mo-cations
are monomeric. The cyclopentadienyl ligands are bound
to molybdenum in a typical g5 manner. No ring slippage
is observed in the planar rings. The values of the Cp–
Mo–Cp bent angles of 135.41°, 136.20°, and 134.79° in
comparison to the other five compounds (Table 1) in-
dicates that they are relatively insensitive to the nature
of the E ligand and its steric demands. More pro-
nounced, and caused by the steric repulsion, are the
observed differences in the E–Mo–E angle (ꢁ74–92°).
All other intramolecular distances and angles lie in the
typical ranges and need no further discussion.
Although air sensitive in solution, 4 is clearly much
more thermally stable than its isoelectronic Nb congener
Table 1
Characteristic bond lengths [A], angles [°], for 1, 2, BF4 and related compounds Mo(g5-C5H4R)2E2
ꢁ
b
1
R: H
E: P(Ph)2H
2,BF4
R: H
[18]b
R: H
[19]b
[20]b
R: H
[20]b
R: H
[21]b
R: H
t
R: but
E1: Me
E2: PMe3
E1: I
E2: P(Ph)2H
E: PMe3
E1: Me
E2: PPh3
E1: H
E2: PPh3
E1: OCH2CF3
E2: P(nbut)3
Bond lengths
Mo–E1
Mo–E2
Mo–Cg1a
Mo–Cg2a
2.5181(9)
2.4928(10)
1.989
2.7989(3)
2.4697(8)
1.971
2.516(2)
2.516(2)
1.978
2.287(8)
2.491(3)
1.996
2.269(5)
2.526(2)
1.988
1.74(7)
2.501(2)
1.970
2.020(9)
2.539(4)
1.974
1.979
1.980
1.982
1.992
1.984
1.980
1.967
Bond angles
E1–Mo–E2
82.77(2)
105.58
108.92
105.15
106.42
135.41
79.60(2)
108.10
106.13
103.86
110.67
134.79
91.55(8)
106.67
104.83
106.66
104.81
134.21
77.4(2)
106.5
105.4
107.1
105.6
138.3
84.1(2)
103.3
105.3
108.1
108.2
135.5
77(3)
99
74.4(3)
107.2
109.6
111.1
105.0
133.7
E1–Mo–Cg1
E1–Mo–Cg2
E2–Mo–Cg1
E2–Mo–Cg2
Cg1–Mo–Cg2
107
108.3
107.8
139.2
a Cg1 (Cg2) denotes the centre of gravity of the cyclopentadienyl moiety C51–C55 (C61–C65).
b The atom labels are adapted to the numbering scheme used in 1.

1266
S.S.M.C. Godinho et al. / Polyhedron 23 (2004) 1263–1270
I
I
Mo
PPh2H
HBF4
PPh2
PPh2
PPh2H
PPh2H
BuLi
Mo
Mo
[BF4]2
1
5
dabco
PPh2H
PPh2
Mo
[BF4]
4
Scheme 3. Synthesis of the molybdenum derivatives 1, 4 and 5.
Cp2Nb(PPh2H)(PPh2) which decomposes readily to the
ortho-metallated species [Cp2Nb(PHPh–C6H4–)] [11].
Further deprotonation was attempted in order to
obtain the neutral bis-phosphido complex Cp2Mo
(PPh2)2, isoelectronic with the well known thiolato li-
gands Cp2Mo(SR)2 and [Cp02Nb(PPh2)2]ꢀ. Reaction of
1, suspended in thf, with LiOMe, LiNEt2, HNa, LiBu,
always at a temperature below )30 °C affords a red so-
lution (see Scheme 3). This fact suggests that deproto-
nation has occurred since the cations 1 and 4 are
insoluble in thf and Cp2Mo(PPh2)2 (5) is expected to be
freely soluble in this solvent. However, the solution is
very unstable and decomposes above )30 °C giving a
brown intractable residue. Similar behavior is observed
in a MeOH/LiOMe system. In order to attempt the
characterization of 5 in situ the reaction of 1 with BuLi
was carried out in a NMR tube at )50 °C. The 31P NMR
spectrum of the red solution in thf-d8 at )40 °C shows
only one singlet resonance at d )24.7 ppm revealing the
presence of only one product, the equivalence of the two
P atoms, and the absence of a PPh2H ligand that should
give a doublet resonance. The integrity of the Cp2Mo
fragment was ascertained by the fact that treatment of
the red solution of 5 with HBF4 ꢂ Et2O led to the pre-
cipitation of 1 in essentially quantitative yield. These
observations strongly support the formulation of 5 as the
bis-phosphido complex Cp2Mo(PPh2)2 (5).
The instability of Cp2Mo(PPh2)2 is not unexpected.
The crystal structure of Cp2Zr(PPh2)2 clearly showed
that the Zr–P bonds are unequal, one of them exhibiting
a clear shortening due to P to Zr backdonation which
results in a partial double bond character [15]. Of
course, in the Cp2Mo (IV) fragment the corresponding
metallocene a1 frontier orbital is filled, thereby pre-
venting this stabilisation and actually creating a desta-
bilising interaction between both P lone pairs and the
filled a1 orbital. One might envisage a possibility of
avoiding this repulsion either by a ring-slippage mech-
anism capable of lowering the electronic density at the
Mo atom or by a rotation of the lone pairs of the P
atoms away from the a1 orbital. The latter possibility
should also exist in the isoelectronic Nb(III) complexes
[Cp02Nb(PPh2)2]- and Cp2Nb(PPh2)(PMe2H). However,
both of them are rather unstable in contrast to the
formally 16 electron Cp2Zr(PPh2)2, suggesting that this
rotation is not enough to stabilise the complexes. The
fact that indenyl slippage would be more favourable for
the indenyl than for the Cp ring, justified our attempts
to synthesize the analogous compounds for the Ind-
CpMo fragment. Unfortunately, we were unable to
obtain any of the necessary precursors, namely [Ind-
CpMo(PPh2H)2]2þ
.
The cation [IndMo(CO)2(PPh2H)2]BF4 (3) also un-
dergoes deprotonation by addition of NEt3 or NaH, but

S.S.M.C. Godinho et al. / Polyhedron 23 (2004) 1263–1270
1267
the solutions obtained are unstable and no products
could be clearly identified.
4.1. Preparation of [Cp2Mo(PPh2H)2][BF4]2 (1)
One alternative possibility of stabilizing the structure
of 5 would be its coordination to electrophilic species
capable of coordinating the P donor atoms. This was
attempted by reacting the solution of 5 at )30 °C with
electrophilic, unsaturated metal fragments or precursors
like CoBr2(thf)2, NiBr2(thf)2, (NBD)Mo(CO)4, Mo(g3-
C3H5)(CO)2(NCMe)2Cl. In no case was there possible
to isolate some compound corresponding to the adducts
of general type Cp2Mo(l-PPh2)2M0Ln. Instead, succes-
sive color changes and or mixtures of products were
obtained. The reaction of 1 with Cp2ZrMe2 expected to
liberate CH4 and form [Cp2Mo(l-PPh2)2ZrCp2]2þ was
also unsuccessful. Clearly, the reactivity of Cp2Mo
(PPh2)2 (5) seems to be rather complex and simple ad-
duct formation with other metal centers is not the main
reaction pathway.
A suspension of Cp2MoI2 (0.3 g, 0.62 mmol) in
NCMe (20 ml) was treated with PPh2H (0.36 ml, 1.49
mmol) and the reaction mixture was stirred overnight
under reflux in the absence of light. To the resulting
greyish solution was added an excess of TlBF4 and the
mixture was left under reflux for another 2 h, in the
absence of light. The solution was filtered through celite
to separate the TlI, the filtrate was taken to dryness and
the residue washed with Et2O and dried under vacuum
to yield the title compound 1 as a yellow powder. Re-
crystallisation from NCMe/Et2O affords orange–yellow
crystals. When Cp2MoCl2 or the corresponding dibro-
mide was used as a starting material, under the same
conditions, similar results were obtained. Yield: 0.34 g
(72.5%). Selected IR (KBr, cmꢀ1): 2211, broad, m(PH),
1085, vs, m(BF). Anal. Calc. for C34H32B2F8MoP2: C,
1
52.89; H, 4.18. Found: C, 52.78; H, 4.07%. H NMR
(Me2CO-d6, d ppm): 7.60–7.53 (m, 20H, Ph), 7.60 (d,
2H, JP–H ¼ 405 Hz, P–H), 5.99 (t, 10H, JP–H ¼ 2 Hz,
Cp). 31P NMR (CD2Cl2/NCMe-d3, d ppm): 20.45 (d,
JP–H ¼ 396.0 Hz, P–H).
3. Conclusions
Several diphenylphospine derivatives of molybdeno-
cene were prepared, two of them characterised by X-ray
diffraction. The dication [Cp2Mo(PPh2H)2]2þ (1) can be
deprotonated to the mono-phosphido complex [Cp2Mo
(PPh2)(PPh2H)][BF4] (4) by Et3N or dabco. In thf, de-
protonation with LiBu at )40 °C forms the bis-phos-
phido complex Cp2Mo(PPh2)2 (5). Due to its thermal
instability 5 was only characterised by its 31P NMR
spectrum, showing a singlet at d )24.7 ppm, and by its
reaction with HBF4 to give 1. Disappointingly, the high
reactivity of Cp2Mo(PPh2)2 seems to limit its use as an
organometallic ligand in contrast to the isostructural
Cp2Zr(PPh2)2 and the isoelectronic Cp2Mo(SR)2 both
of which have a rich chemistry in this regard.
4.2. Preparation of [Cp2MoI(PPh2H)]þ
4.2.1. Preparation of [Cp2MoI(PPh2H)][BF4] (2, BF4)
A solution of Cp2MoI(SPh) (0.88 g, 1.91 mmol) in
CH2Cl2 (50 ml) was treated with a slight excess of
HBF4 ꢂ Et2O giving a dark green solution, which was
stirred for 15 min. Then, in the absence of light, a slight
excess of PPh2H (0.4 ml) was added and the solution
was stirred for another 30 min giving a brownish solu-
tion. The volume was reduced to a fifth and the solution
was filtered. The resulting precipitate was washed twice
with Et2O, further washed with CH2Cl2 and hexane and
dried under vacuum. Recrystallisation from a mixture of
Me2CO, EtOH and Et2O at 4 °C gave red single crystals
of [Cp2MoI(PPh2H)][BF4] suitable for X-ray analysis.
Yield: 0.63 g (53%). Selected IR (KBr, cmꢀ1): 2295, w,
m(PH), 1084, vs, m(BF). Anal. Calc. for C22H21BF4IMoP:
C, 42.21; H, 3.38. Found: C, 42.35; H, 3.41%. 1H NMR
(NCMe-d3, d ppm): 7.67–7.51 (m, 10H, Ph); 7.82 (d, 1H,
JP–H ¼ 404.0 Hz, P–H); 5.47 (s, 10H, Cp). 31P NMR
(CD2Cl2/NCMe-d3, d ppm): 27.53 (d, JP–H ¼ 405.8 Hz,
P–H).
4. Experimental
All operations were carried out under an atmosphere
of dinitrogen with standar Schlenk line and glove-box
techniques. Solvents were purified by conventional
1
methods and distilled under nitrogen prior to use. H
and 31P NMR spectra were measured on a Bruker CXP
300 spectrometer (H, 300 MHz, 31P, 121.49 MHz), ref-
erenced internally to SiMe4 and externally to 85%
H3PO4, respectively. IR spectra were measured on an
Unicam Mattson model 7000 FTIR spectrometer. Ele-
4.2.2. Preparation of [Cp2MoI(PPh2H)]I (2,I)
A suspension of Cp2MoI2 (0.3 g, 0.63 mmol) in
NCMe (20 ml) was treated with 2 equivalents of PPh2H.
The reaction mixture was stirred overnight under reflux,
in the absence of light. The resulting purple solution was
filtered and the filtrate was concentrated to yield
[Cp2MoI(PPh2H)]I as a bordeaux solid. Yield: 0.19 g
(24%). Selected IR (KBr, cmꢀ1): 2309, w, m(PH), 1099,
vs, m(BF). Anal. Calc. for C22H21I2MoP: C, 39.67; H,
~
mental analyses were performed by Maria Conceicßao
Almeida in the Elemental Analysis Service of ITQB.
All common chemicals and solvents were purchased
from commercial suppliers. The synthesis of [CpMo(g5-
C5H6)(CO)2][BF4] [16], [IndMo(g5-C5H6)(CO)2][BF4]
[16], Cp2MoI2 [16], Cp2MoCl2 [12], was done according
to literature procedures.

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S.S.M.C. Godinho et al. / Polyhedron 23 (2004) 1263–1270
1
3.18. Found: C, 39.88; H, 3.31%. H NMR (CD2Cl2/
NCMe-d3, d ppm): 7.78–7.19 (m, 10H, Ph); 7.11 (d, 1H,
JP–H ¼ 402.0 Hz, P–H); 5.54 (s, 10H, Cp). 31P NMR
(CD2Cl2/NCMe-d3, d ppm): 24.58 (d, JP–H ¼ 403.4 Hz,
P–H).
4.6. Single crystal X-ray structure determination exper-
iments
4.6.1. Structure determination of compound 1
Details of the X-ray experiment, data reduction, and
final structure refinement calculation are summarized in
Table 2. Crystals of complex 1 suitable for an X-ray
structure determination were grown from a saturated
solution of 1 in a NCMe/Et2O. A clear orange–yellow
fragment (0.20 ꢃ 0.40 ꢃ 0.50 mm) was stored under
perfluorinated ether, transferred in a Lindemann capil-
lary, fixed and sealed. Preliminary examination and data
collection were carried out on a four-circle diffractom-
eter (NONIUS CAD4) at the window of a sealed tube
4.3. Preparation of [IndMo(CO)2(PPh2H)2][BF4] (3)
A solution of IndMo(g3-C3H5)(CO)2 (0.34 g, 1.10
mmol) in CH2Cl2 (15 ml) was treated with 1 equiv of
HBF4 ꢂ Et2O. After 5 min stirring at room temperature,
the deep red solution was cooled in an ice bath and was
treated with 2 equiv of PPh2H in the absence of light.
The solution was allowed to warm up to room temper-
ature and after stirring for 1 h, the volume was reduced
to half and Et2O (30 ml) was added to precipitate a red
powder. The solid was further washed with Et2O and
the product was recrystallised from a mixture of
Me2CO, EtOH and Et2O at room temperature to afford
yellow crystals of the title compound 3. Yield: 0.33 g
(42%). Anal. Calc. for C35H29BF4MoP2: C, 60.55; H,
4.21. Found: C, 60.68; H, 4.22%. Selected IR (KBr,
cmꢀ1): 2068, w, m(PH), 1977, vs, m(CO), 1898, vs, m(CO),
(
NONIUS FR590; 50 kV; 30 mA; 1.5 kW) and graphite
ꢁ
monochromated Mo Ka radiation (k ¼ 0:71073 A). The
unit cell parameters were obtained by full-matrix least-
squares refinement of 24 high angle reflections. Data
collection was performed at 193 K within a H-range of
1:52° < H < 24:97° and an exposing time of maximum
90 s per scan (omega scans; scan width (1.00 + 0.25 tan
H)° ꢄ 25% at each side of the reflection to determine the
background). A total of 6295 intensities were collected
[17a]. Raw data were corrected for Lorentz and polari-
zation effects. Corrections for absorption effects (based
1081, vs, m(BF). H NMR (Me2CO-d6, d ppm): 7.69–
1
7.53 (m, 20H, Ph); 7.39–7.35 (m, 2H, H5ꢀ8); 7.28–7.15
(m, 2H, H5-8); 7.27 (d, 2H, JP–H ¼ 392.7 Hz, P–H); 6.08
(d, 2H, H1=3); 6.02 (t, 1H, H2). 31P NMR (Me2CO-d6, d
ppm): 34.55 (d, JP–H ¼ 393.6 Hz, P–H).
Table 2
Crystal data and summary of intensity data collection and structure
refinement of 1 and 2,BF4
4.4. Preparation of [Cp2Mo(PPh2)(PPh2H)][BF4] (4)
1
2,BF4
Formula
Formula weight
Color/shape
C34H32B2F8MoP2
772.10
C22H21BF4IMoP
626.01
bordeaux/fragment
A slight excess of dabco (0.12 g, 1.07 mmol) was ad-
ded to a solution of [Cp2Mo(PPh2H)2][BF2]2 (0.4 g, 0.56
mmol) in dichloromethane (30 ml). The solution im-
mediately changed from the initial yellow colour to an
orange solution with a white precipitate. The mixture
was stirred for 1 h and the solution was filtered. The
filtrate was concentrated to dryness and the residue was
washed with ether to yield the title compound 4 as an
orange solid. Yield: 0.35 g (92%). Selected IR (KBr,
cmꢀ1): 1084, vs, m(BF). Anal. Calc. for C34H31BF4MoP2:
C, 59.68; H, 4.57. Found: C, 59. 86; H, 4.62%. 1H NMR
(Me2CO-d6, d ppm): 7.80–7.20 (m, 20H, Ph); 5.34 (t,
10H, Cp). 31P NMR (Me2CO-d6, d ppm): 41.1 (d, JP–H
¼ 393.6 Hz, PPh2H); )11.9 (s, PPh2).
orange–yellow/frag-
ment
Crystal system
Space group
monoclinic
P21=c (No. 14)
13.736(4)
14.240(2)
17.322(5)
102.45(1)
3308.5(14)
4
monoclinic
P21=n (No. 14)
10.3922(3)
18.1898(4)
11.7510(4)
90.202(1)
2221.30(11)
4
ꢁ
a (A)
ꢁ
b (A)
ꢁ
c (A)
b (°)
V (A )
3
ꢁ
Z
qcalcd (g cmꢀ3
)
1.550
0.563
1.872
2.092
l (mmꢀ1
Diffractometer
)
NONIUS CAD4
Mo Ka 0.71073
193
NONIUS KAPPACCD
Mo Ka 0.71073
123
ꢁ
k (A)
T (K)
Reflections collected 6295
hkl range
10037
h: )16,15; k: 0,16; l: h: ꢄ12; k: )14,22; l:
4.5. Reaction of [Cp2Mo(PPh2H)2][BF4]2(1) with
BuLi
0,20
5820/0.0125
ꢄ14
Independent reflec-
4448/0.025
tions (Rint
Observed reflections 4739
)
A suspension of 1 in thf-d8 was prepared in a NMR
tube and cooled to )50 °C. Solution of BuLi in hexanes
(1.6 M) was added dropwise. The yellow suspension
4143
(I > rðIÞ)
Parameters refined
580
374
0.0296/0.0322
0.0834/0.0852
R1 (oberved/all data) 0.0254/0.0446
instantaneously changed to a deep red solution. The 31
P
wR2 (observed/all
data)
0.0562/0.0610
NMR spectra was recorded at )40 °C showing a singlet
resonance at )24.7 ppm. 31P NMR (thf-d8, d ppm):
)24.7 (s, PPh2).
GOF (observed/all
data)
1.043/1.043
1.053/1.053

S.S.M.C. Godinho et al. / Polyhedron 23 (2004) 1263–1270
1269
on psi-scans) were applied [17b]. No decay was observed
during the measurement. After merging (Rint ¼ 0:0125)
and rejecting of the systematically absent intensities a
sum of 5820 (all data), 4739 (I > rðIÞ), respectively,
remained and all were used in the further calculations.
The structure was solved by Patterson methods [17c]
and difference Fourier syntheses [17d]. All non-hydro-
gen atoms of the asymmetric unit were refined with
anisotropic thermal displacement parameters. All hy-
drogen atoms were found and refined with individual
isotropic displacement parameters. Full-matrix least-
squares refinements with 580 parameters were carried
clearly. Neutral atom scattering factors for all atoms
and anomalous dispersion corrections for the non-hy-
drogen atoms were taken from INTERNATIONAL TA-
BLES FOR CRYSTALLOGRAPHY [17e]. All calculations
were performed on a DEC 3000 AXP workstation and
an Intel Pentium II PC, with the STRUX-V system [17f],
including the programs PLATON [17g], SIR92 [17j], and
SHELXL-97 [17d].
5. Supporting information available
P
2
out by minimizing
wðFo2 ꢀ Fc2Þ with SHELXL-97
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been de-
posited with the Cambridge Crystallographic Data
Centre as supplementary publication nos. CCDC-
211212 (1) and CCDC-211213 (2). Copies of the data
can be obtained free of charge on application to 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).
weighting scheme and stopped at shift/err <0.001. In
compound 1 a disorder 0.556(6):0.444(6) of three fluo-
rine atoms of one BF4 anion could be resolved clearly.
Neutral atom scattering factors for all atoms and
anomalous dispersion corrections for the non-hydrogen
atoms were taken from INTERNATIONAL TABLES FOR
CRYSTALLOGRAPHY [17e]. All calculations were per-
formed on a DEC 3000 AXP workstation and an Intel
Pentium II PC, with the STRUX-V system [17f], including
the programs PLATON [17g], MOLEN [17b], and
SHELXL-97 [17d].
Acknowledgements
4.6.2. Structure determination of compound 2, BF4
This work was supported by FCT through project
POCTI/36127/QUI/2000. S. S.M.C. Godinho thanks
Praxis XXI for a Ph.D. grant BD3805/96 and B. Royo
thanks Praxis XXI for a postdoctoral grant. We wish to
Crystal data and details of the structure determina-
tion are presented in Table 2. Suitable single crystals for
the X-ray diffraction study were grown from a mixture
of Me2CO, EtOH and Et2O at 4 °C. A red colored
fragment (0.18 ꢃ 0.23 ꢃ 0.38 mm) was stored under
perfluorinated ether, transferred in a Lindemann capil-
lary, fixed and sealed. Preliminary examination and data
collection were carried out on an area detecting system
~
acknowledge Maria da Conceißcao Almeida for provid-
ing data from the Elemental Analyses Service at the
ꢀ
Instituto de Tecnologia Quımica e Biologica, Univer-
sidade Nova de Lisboa, Oeiras, Portugal.
ꢀ
(
(
NONIUS KAPPACCD) at the window of a rotating anode
NONIUS FR951) and graphite monochromated Mo Ka
References
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