A convenient synthesis of bis(phosphino)methanes: Formation of a nickel(II) bis(phosphino)methane monoxide complex

Article abstract of DOI:10.1016/j.ica.2005.12.053

The reaction of (trimethylsilyl)methyl phosphines R₂PCH₂SiMe₃ with chlorophosphines ClPR₂^′ provides ready access to a range of symmetrical or non-symmetrical diphosphinomethanes R₂ PCH₂ PR₂^′. The products are obtained cleanly and can be used directly in the synthesis of transition metal complexes. This is illustrated by the preparation and structural characterization of the corresponding NiCl₂(P-P) derivatives.

Full text of DOI:10.1016/j.ica.2005.12.053

Inorganica Chimica Acta 359 (2006) 3191–3196
www.elsevier.com/locate/ica
A convenient synthesis of bis(phosphino)methanes: Formation of
a nickel(II) bis(phosphino)methane monoxide complex
*
´
Juan Campora , Celia M. Maya, Inmaculada Matas, Birgit Claasen,
´
Pilar Palma, Eleuterio Alvarez
Instituto de Investigaciones Quı´micas, CSIC-Universidad de Sevilla, c/ Ame´rico Vespucio, 49, 41092, Sevilla, Spain
Received 24 November 2005; received in revised form 28 December 2005; accepted 29 December 2005
Available online 5 April 2006
Abstract
The reaction of (trimethylsilyl)methyl phosphines R2PCH2SiMe3 with chlorophosphines ClPR0 provides ready access to a range of
2
symmetrical or non-symmetrical diphosphinomethanes R2PCH2PR02. The products are obtained cleanly and can be used directly in
the synthesis of transition metal complexes. This is illustrated by the preparation and structural characterization of the corresponding
NiCl2(P–P) derivatives.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Diphosphine ligands; Nickel; Diphosphine monoxide
1. Introduction
contributes to further expand their rich coordination
chemistry.
Bidentate phosphine ligands are widely used to stabilize
transition metal complexes either in stable compounds or
as intermediates in homogeneous catalysis [1]. There are
currently many synthetic methods that provide access to
a plethora of diphosphines, allowing precise tuning of the
stereoelectronic properties of the metal center [2]. Bis(phos-
phino)methanes constitute a special group among these
ligands, since their small bite angle results in a tendency
to coordinate either in terminal g1 mode or to bridge
between two metal centres [3]. The presence of bulky
groups on the phosphorus atoms [4] or alkyl substitution
at the methylene group [5] increases the ligand preference
to form chelated complexes, displaying strained four-mem-
bered MPCP cycles. In addition, the relatively acidic
PCH2P group can be easily deprotonated, rendering an
anionic form of the ligands [6] and allowing the ready mod-
ification of the diphosphine backbone [7], a feature that
A number of synthetic methods have been devised to
give access to bis(phosphino)methanes, but most of them
are laborious or require the use of toxic or pyrophoric
materials. Thus, the synthesis of symmetric R2PCH2PR2
ligands usually relies on the alkylation of the dangerous
and difficult to prepare tetrachlorodiphosphine Cl2P-
CH2PCl2 [8], or the reaction of alkali metal phosphides
with dihalomethanes [2]. Hofmann has reported a versatile
procedure, involving the reaction of the lithiated phos-
phines R2PCH2Li with PR02Cl, which allows the synthesis
of several types of symmetric and unsymmetric
ðR2PCH2PR02Þ ligands. A drawback of this method is the
use of relatively large amounts of pyrophoric t-BuLi. In a
safer modification of this strategy, developed by Werner,
the lithiated R2PCH2Li reagent is prepared by reaction of
the organotin derivatives R2PCH2SnPh3 with n-BuLi under
mild conditions. Interestingly, the organotin precursors can
also react directly with chlorophosphines PR02Cl, to afford
the desired diphosphines [9]. A similar condensation using
less toxic organosilicon precursors was reported by Appel
for the preparation of the diphosphines PhP(R)CH2PR2
*
Corresponding author. Tel.: +34 954923384; fax: +34 954460565.
´
E-mail address: campora@iiq.csic.es (J. Campora).
0020-1693/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.12.053

3192
J. Ca´mpora et al. / Inorganica Chimica Acta 359 (2006) 3191–3196
(R = Me, Ph) [10]. Herein, we describe the extension of the
latter methodology for the synthesis of different ligands dis-
playing the PCH2P unit. A simple procedure has been
developed, which minimizes the effort dedicated to the iso-
lation and purification of intermediates. The ligands can be
used as obtained for the preparation of metal complexes,
and this is illustrated with the synthesis of several nickel
derivatives, which have been structurally characterized.
drying with anhydrous MgSO4, they are ready for use with-
out any further purification.
An extension of this methodology allows the synthesis
of polydentate ligands. Also shown in Scheme 1 is the reac-
tion of the phosphine P(CH2SiMe3)3 with ClPPh2 under
the above described reaction conditions, which cleanly
affords the tetraphosphine 5. The identity of the product
is confirmed by its 31P{1H} spectrum, which shows an
AX3 spin system with a coupling constant of 100 Hz, sim-
ilar to that of the diphosphines 2–4. Only one more exam-
ple of this type of CH2-linked tetraphosphines is described
in the literature, namely P(CH2PMe2)3 [13b].
2. Results and discussion
The synthesis of the bis(phosphino)methane derivatives
1–4 has been accomplished as shown in Scheme 1. Com-
pounds 1 [10,11], 2 [10,12] and 4 [13] have been prepared
before by different procedures, but 3 is described for the
first time. Heating an equimolar mixture of the trimethylsi-
lyl derivative R2PCH2SiMe3 and the corresponding chloro-
phosphine without solvent at 250 ꢁC for 20 min cleanly
affords the diphosphines. The only byproduct, ClSiMe3,
is volatile and can be removed completely from the mixture
at the end of the reaction by pumping at room temperature
under reduced pressure. For the relatively small scale used
in this work, the reaction can be safely conduced in a tef-
lon-stopcock sealed 100 mL glass ampoule. However, for
larger size preparations, a pressure reactor would be advis-
able, since the relatively volatile ClSiMe3 may develop
pressure. A conventional reflux apparatus has been
avoided to prevent the contamination of the product by
grease or by the action of ambient moisture. The starting
trimethylsilylmethylphosphines [14] are also readily pre-
pared from the reaction of commercially available
Mg(CH2SiMe3)Cl with ClPR2, and after hydrolysis and
31P NMR monitoring indicates that all the condensation
reactions proceed to completion and only one product is
formed in an essentially quantitative manner. However,
during the synthesis of 3, it was observed the sublimation
of a small amount of a white solid in the cold part of the
reaction vessel. In spite of our efforts, we have been unable
to ascertain the identity of this compound, which displays
complex 31P and 1H spectra. Notwithstanding this, this
solid is easily removed, and the liquid phase is pure enough
for synthetic purposes in all cases.
Ligands 1–3 react with NiCl2 Æ 6(H2O) in ethanol giving
rise to the diamagnetic complexes 6–8. The 31P{1H} spec-
trum of 6 consists of a singlet signal at d ꢀ3.6 ppm, but
those of the unsymmetric ligand derivatives 7 and 8 display
strongly coupled AX spin systems with 2JPP ꢁ 200 Hz. The
large value of the coupling constant is atypical for cis coor-
dinated phosphorus atoms, and indicates an efficient trans-
mission of the PP coupling either through the bridging
carbon atom or the metal center, due to a significant depar-
ture from square planar geometry.
R2PCl + Mg(CH2SiMe3)Cl
R2PCH2SiMe3
R = iPr or Ph
R R
P
R
R'
Cl
Cl
iPr iPr
iPr Ph
6
7
Ni
P
R' R'
iPr Me 8
Δ
R2PCH2SiMe3 + R'2PCl
R2PCH2PR'2
R'
- ClSiMe3
Me
H2O
P
R
Cl
Me
P
Cl
iPr iPr
iPr Ph
1
2
Ph
Ph
Ph
O
Ni
Ni
P
O
iPr Me 3
Ph
Cl
P
Me
Cl
OH2
Ph Me 4
9
Me
Ph2P
Δ
P(CH2SiMe3)3 + PClPh2
P
PPh2
- ClSiMe3
PPh2
5
Scheme 1.

J. Ca´mpora et al. / Inorganica Chimica Acta 359 (2006) 3191–3196
3193
Table 1
The crystal structures of the three compounds are shown
˚
Selected bond distances (A) and bond angles (ꢁ) for compounds 6–8
in Fig. 1, and selected bond lengths and bond angles are
listed in Table 1. The three compounds display distorted
square planar structures. Their most prominent feature
are the acute P–Ni–P angles of ca. 75ꢁ, while the Cl–Ni–
Cl angles are somewhat wider than 90ꢁ. In contrast with
NiCl2(PCy2CH2PCy2) [15], compounds 6–8 display negligi-
ble tetrahedral distortion. The Ni–P and Ni–Cl bond
lengths of 7 are almost unaffected by the different nature
of the R groups attached to the P atoms. Thus, the two
Ni–Cl distances are almost identical within the experimen-
tal error, evincing that the different P donors exert compa-
rable trans influence. However, in 8, the Ni–P(2) bond
6
7
8
Ni–P1
Ni–P2
2.1407(5)
2.1386(5)
2.2091(5)
2.2063(5)
75.366(19)
98.23(2)
91.20(8)
4.33(4)
2.1451(6)
2.1460(6)
2.2068(6)
2.2106(6)
75.60(2)
96.82(2)
91.41(10)
3.64(2)
2.1106(9)
2.1685(9)
2.2293(9)
2.1947(9)
75.03(3)
97.38(3)
90.66(12)
4.49(7)
Ni–Cl1
Ni–Cl2
P1–Ni–P2
Cl1–Ni–Cl2
P1–C1–P2
TDa
a
Tetrahedral distortion, angle formed by planes P1–Ni–P2 and Cl1–Ni–
Cl2.
˚
The oxidation of coordinated phosphine ligands is not
unusual, and it can involve intramolecular nucleophilic
attack at the coordinated phosphorus atom [18]. Several
diphosphine complexes of Ru and Pd undergo monooxida-
tion by reaction with aqueous alkalis, with concomitant
reduction of the metal center [19]. Based on this process,
Grushin has developed a catalytic method for the selective
(2.1685(9) A) is significantly longer than Ni–P(1)
˚
(2.1106(9) A), probably due to the larger hindrance of the
PiPr2 fragment as compared to the smaller PMe2 unit.
The steric origin of this effect is supported by the lack of
a stronger trans influence of the latter group. In fact, the
Ni–Cl2 bond, positioned trans to the presumably more
strongly bound PMe2 fragment, is slightly shorter (by ca.
˚
0.03 A) than Ni–Cl1.
The reaction of ligand 4 with NiCl2 Æ 6(H2O) follows a
different course, and leads to the formation of the brown
paramagnetic compound 9. Its crystal structure (Fig. 2)
reveals that the bidentate ligand has undergone partial oxi-
dation at the PMe2 unit. The complex is binuclear, with the
phosphine monoxide acting as a chelating ligand and
bridging both metal centers through the oxygen atom. This
is a very unusual feature, since only one example of struc-
turally authenticated bridging coordination of a phosphine
oxide has been reported previously [16]. The IR band asso-
ciated to the P@O bond can be tentatively assigned to a
medium intensity absorption at 1094 cmꢀ1. This frequency
is somewhat lower than in structurally related complexes
displaying terminal P@O coordination (ca. 1150 cmꢀ1
)
[17]. The nickel atoms are in a pseudooctahedral environ-
ment, which is completed by the two chloro ligands and
a molecule of water. A planar ClPNi(l-O)2NiClP frame-
work composes the core of the molecule. The P@O bridges
are very symmetrical, with almost identical Ni–O bond dis-
˚
Fig. 2. Crystal structure of compound 9. Selected bond distances (A) and
bond angles (ꢁ): Ni1–P1, 2.381(2); Ni1–O1, 2.161(4); Ni1–O10, 2.127(5);
Ni1–O2, 2.077(5); Ni1–Cl1, 2.3438(17), Ni1–Cl2, 2.3924(18); P2–O1,
1.510(5) and P1–Ni1–O1, 84.59(13); Ni–O1–Ni10, 101.29(19); O1–Ni1–
O10, 78.70(19); P1–C1–P2, 111.1(3).
˚
tances (Ni–O1, 2.127(5) and Ni–O1A, 2.160(4) A).
Fig. 1. Crystal structure of compounds 6–8.

3194
J. Ca´mpora et al. / Inorganica Chimica Acta 359 (2006) 3191–3196
1
The 13C and H resonances of the solvent were used as
H
H
O
Ph
Ph
Ph
an internal standard, and chemical shifts are reported with
respect to SiMe4. 31P chemical shifts are reported downfield
of an external solution of H3PO4 (80%).
Ph
P
- HCl
Cl
Cl
P
P
Cl
4
+ NiCl2(H2O)x
Ni
Ni
P
OH
Me
Me
Me
Me
4.1. Synthesis of R2PCH2SiMe3 (R = iPr [14a], Ph [14b])
Ph
Ph
Ni
Ph
Ph
Ni
19.8 mL of a 1.6 M solution of Mg(CH2SiMe3)Cl
(31.4 mmol) were added dropwise to stirred solution of
PR2Cl (31.4 mmol) in diethyl ether, cooled to ꢀ80 ꢁC.
After stirring for 6 h at room temperature, a saturated
solution of NH4Cl was added. The mixture was decanted
and the two layers were separated. The aqueous solution
was washed with Et2O (3 · 20 mL), and the washings com-
bined with the organic phase. The resulting solution was
dried with anhydrous MgSO4, and the solvent removed
under reduced pressure, affording the product as a colorless
x 2
+ H2O
+ HCl
- H2
P
P
Cl
Cl
Cl
9
Me
Me
P
P
H
O
O
Me
Me
Scheme 2.
oxidation of diphosphines [17]. Since the reaction leading
to compound 9 takes place under nitrogen atmosphere with
careful exclusion of air, oxidation of the ligand by air seems
unlikely. Therefore, we consider the water present in the
starting hydrated nickel chloride as the most probable
source of oxygen. As the oxidation state of Ni does not
change along the process, water also acts as the final elec-
tron acceptor, releasing H2. A possible mechanism for this
reaction is shown in Scheme 2. The hydrolysis of a Ni–Cl
bond generates a hydroxo ligand, which then attacks the
coordinated P atom. The resulting nickel hydride reacts
with the HCl generated by the hydrolysis, releasing hydro-
gen and giving rise to the NiCl2 complex, which subse-
quently dimerizes to afford the final product.
i
oil. Pr2PCH2SiMe3; Yield: 3.8 g (59%). 31P{1H} NMR
(C6D6, 25 ꢁC): d ꢀ5.0 ppm. Ph2PCH2SiMe3; Yield: 6.6 g
(77%). 31P{1H} NMR (C6D6, 25 ꢁC): d ꢀ22.8 ppm.
4.2. Synthesis of diphosphines 1–4
Equimolar amounts (4 mmol) of R2PCH2SiMe3 and
PClR02 were mixed in a 100 mL glass ampoule, sealed with
a teflon stopcock, and heated with magnetic stirring at
250 ꢁC for 20 min. The heating was confined to the lower
part of the ampoule, to allow ClSiMe3 to condense in the
upper part. Caution. For larger scale preparations, a pres-
sure reactor should be used. The mixture was cooled to room
temperature and the ClSiMe3 was evaporated in vacuo.
iPr2PCH2PiPr2 (1) [10,11]. Yield: 3.95 g (86%).
31P{1H} NMR (C6D6, 25 ꢁC): d ꢀ3.6 ppm.
3. Conclusions
Trimethylsilylmethyl phosphines react cleanly with chlo-
rophosphines, providing a convenient method for the syn-
thesis of different types of methylene bridged ligands, such
as symmetrical and unsymmetrical diphosphinomethanes.
The method can be extended to the preparation of polyden-
tate ligands such as the tetraphosphine 5. The reaction pro-
ceeds without solvent, and the ligands are directly obtained
pure enough for synthetic purposes. This is demonstrated
by the clean formation of the nickel complexes 6–8, which
have been structurally characterized. The reaction of
hydrated nickel chloride with ligand 4 afforded the phos-
phine monoxide 9, probably as a result of intramolecular
attack of water to the coordinated phosphorus atom.
iPr2PCH2PPh2 (2) [10,12]. Yield: 1.06 g (84%).
2
31P{1H} NMR (C6D6, 25 ꢁC): d ꢀ20.6 (d, JPP = 117 Hz),
ꢀ4.1 (d) ppm.
iPr2PCH2PMe2 (3). Quantitative yield. 1H NMR
2
(C6D6, 25 ꢁC): d 0.99 (d, 6H, JHP = 3.0 Hz, PMe2), 0.99
3
3
(partially hidden dd, 6H, JHH = 7.0 Hz, JHP = 1.1, CH
3
3
MeMe), 1.04 (dd, 6H, JHH = 7.0 Hz, JHP = 4.2,
2
CHMeMe), 1.19 (br d, 2H, J ꢁ 3.0 Hz, CH2), 1.60 (sept
d, 2H, CHMe2) ppm. 13C{1H} NMR (C6D6, 25 ꢁC) d =
1
3
15.8 (dd, JCP = 15 Hz, JCP = 9 Hz, PMe2), 18.6 (dd,
2JCP = 10 Hz, JCP = 2 Hz, CH MeMe), 19.8 (d, JCP
4
2
1
3
= 16 Hz, CHMeMe), 24.0 (dd, JCP = 15 Hz, JCP = 6 Hz,
1
4. Experimental
CHMe2), 24.4 (dd, JCP = 20 Hz, 32 Hz, CH2) ppm.
31P{1H} NMR (C6D6, 25 ꢁC): d ꢀ53.4 (d, JPP = 98 Hz),
2
All preparations and other operations were carried out
under oxygen-free nitrogen atmosphere, using conventional
Schlenk techniques. Diethyl ether and dichloromethane
were dried and degassed before use. Absolute ethanol
and the compounds PPh2Cl, PiPr2Cl were used as pur-
chased. PMe2Cl [20] and P(CH2SiMe3)3 [21] were prepared
according to literature methods. Microanalysis were per-
formed by the Analytical Service of the Instituto de Inves-
ꢀ5.7 (d) ppm.
Ph2PCH2PMe2 (4) [13]. Quantitative yield. 31P{1H}
NMR (C6D6, 25 ꢁC): d ꢀ53.3 (d, JPP = 102 Hz), ꢀ20.5
2
(d) ppm.
4.3. Synthesis of P(CH2PPh2)3 (5)
This compound was prepared as described for 1–4, from
´
tigaciones Quımicas. NMR spectra were recorded using
Bruker DPX-300, DRX-400 and DRX-500 spectrometers.
0.73 g (2.5 mmol) of P(CH2SiMe3)3 and 1.34 mL (7.5 mmol)
1
of PPh2Cl. Quantitative yield. H NMR (C6D6, 25 ꢁC): d

J. Ca´mpora et al. / Inorganica Chimica Acta 359 (2006) 3191–3196
3195
3
2.42 (d, 6H, 2JHP = 1.9 Hz, CH2), 7.03 (m, 9H, CarH), 7.43
(m, 6H, CarH) ppm. 13C{1H} NMR (C6D6, 25 ꢁC): d 28.5
(m, CH2), 128.8 (d, JCP = 6 Hz, CarH), 128.9 (s, CarH),
133.5 (d, JCP = 19 Hz, CarH), 140.0 (d, JCP = 15 Hz, Car)
ppm. 31P{1H} NMR (C6D6, 25 ꢁC): d ꢀ36.5 (q, 1P,
2JPP = 100 Hz), ꢀ25.2 (d, 3P, 2JPP = 100 Hz) ppm.
= 18.8 Hz, JHH = 6.9 Hz, CH3), 2.34 (m, 2H, CH), 2.79
(t, 2H, 2JHP = 10.0 Hz, CH2), 7.55 (m, 4H, CHar), 7.60 (m,
2H, CHar), 8.16 (m, 4H, CHar) ppm. 13C{1H} NMR
(CD2Cl2, 25 ꢁC): d 17.2 (s, CHMeMe), 18.8 (s, CHMeMe),
1
1
23.8 (dd, JCP = 29 Hz, JCP = 21 Hz, CH2), 25.4 (d,
1JCP = 19 Hz, CHMe2), 127.7 (d, 1JCP = 41 Hz, Car), 129.6
(d, JCP = 11 Hz, CHar), 132.5 (d, JCP = 2 Hz, CHar), 133.3
(d, JCP = 11 Hz, CHar) ppm. 31P{1H} NMR (CD2Cl2,
25 ꢁC): d ꢀ51.7 (d, 2JPP = 183 Hz), ꢀ10.3 (d) ppm.
4.4. Synthesis of complexes NiCl2(P–P) 6–8
A solution of 1 mmol of the appropriate diphosphine in
10 mL of anhydrous EtOH was added to a stirred solution
of NiCl2 Æ 6H2O (0.378 g, 1 mmol) in the same solvent. An
immediate change of color from green to orange was
observed. The mixture was stirred at room temperature
for 1 h, and the solvent stripped to dryness. The orange res-
idue was recrystallized from a minimum amount of
dichloromethane.
NiCl2(iPr2CH2PMe2) (8). Yield: 997 mg (77%). Anal.
Calc. for C9H22Cl2P2Ni: C, 33.6; H, 6.9. Found: C, 33.4;
1
3
H, 6.7%. H NMR (CD2Cl2, 25 ꢁC): d 1.39 (dd, 6H, JHP
3
= 17.0 Hz, JHH = 7.8 Hz, CH MeMe), 1.63 (dd, 6H,
3JHP = 18.8 Hz, JHH = 7.0 Hz, CHMe Me), 1.71 (d, 6H,
3
2JHP = 13.3 Hz, PMe2), 2.29 (4H, m, CH + CH2) ppm.
13C{1H} NMR (CD2Cl2, 25 ꢁC): d 13.1 (d, JCP = 26 Hz,
1
PMe2), 17.3 (s, CH MeMe), 18.7 (s, CHMeMe), 21.8 (dd,
NiCl2(iPr2PCH2PiPr2) (6). Yield: 227 mg (60%). 1H
1JCP = 28 Hz, JCP = 23 Hz, CH2), 24.4 (d, JCP = 17 Hz,
1
1
3
NMR (CD2Cl2, 25 ꢁC): d 1.38 (dd, 12H, JHH = 7.1 Hz,
CHMe2) ppm. 31P{1H} NMR (CD2Cl2, 25 ꢁC): d ꢀ53.7
3
2
3JHP = 8.5 Hz, CHMeMe), 1.57 (dd, 12H, JHH = 7.3,
(d, JPP = 201 Hz), ꢀ14.3(d) ppm.
2
3JHP = 10.1, CHMeMe), 2.11 (t, 2H, JHP = 19.1 Hz,
CH2), 2.49 (m, 4H, CHMe2) ppm. 31P{1H} NMR (CD2Cl2,
25 ꢁC): d ꢀ15.7 ppm.
4.5. Synthesis of [NiCl2(H2O)-l2O-(Ph2PCH2P(O)
Me2)-jP,O]2 (9)
NiCl2(iPr2CH2PPh2) (7). Yield: 370 mg (83%). Anal.
Calc. for C19H26Cl2P2Ni: C, 51.2; H, 5.9. Found: C, 51.3;
H, 5.9%. 1H NMR (CD2Cl2, 25 ꢁC): d 1.26 (dd, 6H,
0.24 g (1 mmol) of NiCl2 Æ 6H2O, dissolved in 10 mL of
EtOH was added to a stirred solution of Ph2PCH2PMe2
(0.26 g, 1 mmol) in the same solvent. The color of the
3
3
3JHP = 17.0 Hz, JHH = 6.8 Hz, CH3), 1.58 (dd, 6H, JHP
Table 2
Crystallographic data collection, intensity measurements and structure refinement parameters for 6–9
6
7
8
9 Æ 2CH2Cl2
Chemical formula
FW
T (K)
C13H30Cl2NiP2
377.92
100(2)
C19H26Cl2NiP2
445.95
173(2)
C9H22Cl2NiP2
321.82
173(2)
C32H40Cl4Ni2O4P4, 2(CH2Cl2)
1017.57
173(2)
Crystal size (mm)
Crystal system
Space group
0.29 · 0.25 · 0.22
monoclinic
P21/n
13.3547(8)
10.6673(6)
14.3456(9)
90
116.312(1)
90
1831.92(19)
4
0.41 · 0.14 · 0.12
monoclinic
P21/n
11.2246(7)
15.2315(10)
12.5104(8)
90
104.719(1)
90
2068.7(2)
4
0.31 · 0.20 · 0.09
orthorhombic
Iba2
13.5112(9)
13.8541(9)
16.0689(11)
90
90
90
3007.9(3)
8
1.825
0.36 · 0.34 · 0.29
monoclinic
P21/n
11.6984(9)
14.3799(11)
12.7223(10)
90
98.329(2)
90
2117.6(3)
2
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
l (mmꢀ1
)
1.510
1.370
800
1.350
1.432
928
1.580
1.596
1040
Dcalc (g cmꢀ3
F(000)
)
1.421
1344
h Range (ꢁ)
Number of measured reflections
2.48–28.71
16734
2.15–28.00
12265
2.11–28.70
9388
2.15–28.04
12438
Number of unique reflections [Rint
]
4422 [0.0316]
0.6669 and 0.7373
4422/0/283
0.0307
4748 [0.0401]
0.3992 and 0.5252
4748/0/218
0.0310
3475 [0.0424]
0.6015 and 0.8529
3475/1/133
0.0303
4836 [0.0493]
0.6001 and 0.6572
4836/3/228
0.0801
Minimum and maximum transmission fact
Number of data/restraints/parameter
R(F)(F2 P 2r(F2))a
Observed reflections
3628
0.0664
0.981
3212
0.0524
0.925
2791
0.0505
0.951
0.016(14)
3202
0.2423
1.093
wR(F2) [all data]b
Goodness-of-fitc [all data]
Absolute structure parameterd
P
P
a
b
c
R(F) = iFo| ꢀ |Fci/ iFo| for 13567 11i (or 12034 12i) observed reflections.
P
P
2
2
1=2
wRðF 2Þ ¼ ð ½wðF o2 ꢀ F c2Þ ꢂ= ½wðF 2oÞ ꢂÞ
.
P
2
Goodness-of-fit ¼ ð ½wðF 2o ꢀ F c2Þ ꢂ=ðn ꢀ pÞÞ1=2, where n and p are the number of data and parameters.
d
Ref. [23].

3196
J. Ca´mpora et al. / Inorganica Chimica Acta 359 (2006) 3191–3196
(b) P. Dierkes, P.W.N.M. van Leeuwen, J. Chem. Soc., Dalton
Trans. (1999) 1519.
mixture changed from green to brown. After stirring for
1 h, the solvent was removed under reduced pressure.
The brown residue was washed with Et2O, and recrystal-
lized from CH2Cl2. Yield: 466 mg (55%). FT-IR (Nujol
mull): m 1094 cmꢀ1 (P@O).
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4.6. X-ray crystal structure analyses of 6–9
´
[4] L.J. Manojlovic-Muir, K.W. Muir, A.A. Frew, S.S.M. Ling, M.A.
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A single crystal, of each representative compound (red
block 6, orange block 7, orange prism 8 and green block
9 Æ 2CH2Cl2), of suitable size was mounted on a glass
fiber using perfluoropolyether oil (FOMBLINꢂ 140/13,
Aldrich). A summary of crystallographic data and structure
refinement is reported in Table 2. Intensity data for 6 were
collected on a Bruker-AXS SMART diffractometer/APEX
CCD area detector, equipped with a graphite monocro-
´
[6] See for example: (a) J. Ruiz, M.E.G. Mosquera, G. Garcıa, E.
´
´
Padron, V. Riera, S. Garcıa-Grandas, F. van der Maaien, Angew.
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˚
mated Mo Ka1 radiation (k = 0.71073 A) and a Bruker
low-temperature device, whereas the data collections for
complexes 7–9 were performed on a Siemens SMART 1 K
diffractometer/CCD area detector, equipped with a graphite
´
[8] L.J. Manojlovic-Muir, I.R. Jobe, B.J. Maya, R.J. Puddephatt, J.
Chem. Soc., Dalton Trans. (1987) 2117.
˚
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Trans. (1999) 1867.
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monochrotomator k(Mo Ka1 radiation) = 0.71073 A and
an Oxford Cryosystem low-temperature device. The data
collection strategy used in all the instance was x rotations
with narrow frames. Instrument and crystal stability were
evaluated from the measurement of equivalent reflections
at different measuring times and no decay was observed.
The data were reduced using SAINT [22a] and corrected for
Lorentz and polarization effects, and a semiempirical
absorption correction was applied using SADABS [22b]. The
structure was solved by direct methods using SIR-2002
[22c] and refined against all F2 data by full-matrix least-
squares techniques using SHELXTL-6.12 [22d] minimizing
(b) D.J. Peterson, J. Org. Chem. 33 (1968) 780.
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2
w½F 2o ꢀ F 2cꢂ . All the non-hydrogen atoms were refined with
anisotropic displacement parameters. The hydrogen atoms
of compounds 7–9 were included from calculated positions
and refined riding on their respective carbon atoms with iso-
tropic displacement parameters. For compound 6, the H
atom positions were refined freely. Complete structural data
have been deposited with CCDC Reference Nos. 286620 (6),
286621 (7), 286622 (8) and 286623 (9).
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21 (2002) 4672;
Acknowledgments
(b) V.V. Grushin, H. Alper, Organometallics 12 (1993) 1800.
[20] G.W. Parshall, Inorg. Synth. 15 (1974) 191.
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[22] (a) SAINT 6.02, Bruker AXS, Inc., Madison, WI 53711-5373, USA,
1997–1999z;
Financial support from the DGI (Project PPQ2003-
´
00975) and Junta de Andalucıa are gratefully acknowl-
edged. I.M. thanks a research fellowship from the Consejo
´
Superior de Investigaciones Cientıficas (I3P Program).
(b) SADABS George Sheldrick, Bruker AXS, Inc., Madison, WI, USA,
1999;
(c) M.C. Burla, M. Camalli, B. Carrozzini, G.L. Cascarano, C.
Giacovazzo, G. Polidori, R. Spagna, SIR2002: The Program, J. Appl.
Crystallogr. 36 (2003) 1103;
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