General route for the synthesis of terminal phosphanylphosphido complexes of Zr(IV) and Hf(IV): Structural investigations of the first zirconium complex with a phosphanylphosphido ligand

Article abstract of DOI:10.1016/j.poly.2011.01.031

Reactions of R₂P-P(SiMe₃)Li with [Cp ₂MCl₂] (M = Zr, Hf) in hydrocarbons yield the related terminal phosphanylphosphido complexes [Cp₂M(Cl){(Me ₃Si)P-PR₂-κP¹}] (R = ⁱPr and ^tBu). The solid state structures of [Cp₂M(Cl){P(SiMe ₃)-PⁱPr₂-κP¹}] (M = Zr, Hf) were established by single crystal X-ray diffraction studies. The phosphido-P atoms adopt almost planar geometries and the phosphanyl P atoms adopt pyramidal geometries. The reaction of a mixture of (Me₃Si)₂PLi and Ph₂P-P(SiMe₃)Li with [CpZrCl₃] in toluene yields the dinuclear complex [Cp₂Zr₂Cl₅(Ph ₂PPPSiMe₃)(Li THF DME)].

Full text of DOI:10.1016/j.poly.2011.01.031

Polyhedron 30 (2011) 1238–1243
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Polyhedron
journal homepage: www.elsevier.com/locate/poly
General route for the synthesis of terminal phosphanylphosphido complexes
of Zr(IV) and Hf(IV): Structural investigations of the first zirconium complex
with a phosphanylphosphido ligand
a
a
a
b
a,
⇑
´
Rafał Grubba , Aleksandra Wisniewska , Katarzyna Baranowska , Eberhard Matern , Jerzy Pikies
a Chemical Faculty, Department of Inorganic Chemistry, Gdansk University of Technology, G. Narutowicza St. 11/12., Pl-80-233 Gdansk, Poland
b Institut für Anorganische Chemie, Universität Karlsruhe (TH), D-76128 Karlsruhe, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Reactions of R2P–P(SiMe3)Li with [Cp2MCl2] (M = Zr, Hf) in hydrocarbons yield the related terminal phos-
phanylphosphido complexes [Cp2M(Cl){(Me3Si)P–PR2-
P1}] (R = iPr and tBu). The solid state structures of
[Cp2M(Cl){P(SiMe3)–PiPr2- P1}] (M = Zr, Hf) were established by single crystal X-ray diffraction studies.
The phosphido-P atoms adopt almost planar geometries and the phosphanyl P atoms adopt pyramidal
geometries. The reaction of a mixture of (Me3Si)2PLi and Ph2P–P(SiMe3)Li with [CpZrCl3] in toluene yields
the dinuclear complex [Cp2Zr2Cl5(Ph2PPPSiMe3)(Li THF DME)].
Received 15 December 2010
Accepted 28 January 2011
Available online 12 February 2011
j
j
Dedicated to Professor Hansgeorg Schnöckel
on the occasion of his 70th birthday
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
P ligands
Zirconium
Hafnium
1. Introduction
2. Experimental
Group(IV) metallocenes with organylphosphido ligands have
been a subject of thorough studies [1]. An important entrance to
this class of compounds are reactions of related metallocene dichlo-
rides [Cp2MCl2] (M = Zr, Hf; Cp = cyclopentadienyl or substituted
cyclopentadienyl) with lithium derivatives of primary and second-
ary phosphanes of medium or large steric effects leading to the for-
mations of disubstituted [2–10] and monosubstituted [2,10–16]
compounds, which were in part structurally characterized. Low
temperature and dropwise addition of reagents suppress the forma-
tion of diphosphanes and cyclic dinuclear M(III) complexes [3,17].
In the course of our work upon the reactivity of lithiated diphos-
phanes R2P–P(SiMe3)Li (R = tBu, Et2N, iPr2N) towards group(IV)
dichlorometallocenes we have established that these compounds
can act as precursors for two types of new organophosphorus li-
gands: phosphanylphosphidene R2P–P ligands [18] and terminal
phosphanylphosphido ligands R2P–P(SiMe3) [19]. Scheme 1 shows
the structures of phosphanylphosphido complexes compared to
the well-known ‘‘classical’’ phosphido complexes.
Toluene and THF were dried over Na/benzophenone and dis-
tilled under nitrogen. Pentane was dried over Na/benzophenone/
diglyme and distilled under nitrogen. All manipulations were per-
formed in flame-dried Schlenk type glassware on a vacuum line.
31P and 1H NMR spectra were recorded on Bruker AC250, Bruker
AMX300 and Bruker AV400 MHz spectrometers (external standard
85% H3PO4) at ambient temperature. The simulation and iteration
of spectra was made using Bruker software [21]. For the numbering
of atoms see Schemes 1 and 3, Figs. 1–3. [Cp2ZrCl2] was purchased
from Aldrich. Literature methods were used to prepare [Cp2HfCl2]
[22], tBu2P–P(SiMe3)Li [23], iPr2P–P(SiMe3)Li, Ph2P–P(SiMe3)Li
[24] and [CpZrCl3] [25]. Ph2P–P(SiMe3)Li could not be obtained in
pure form because during the lithiation of Ph2P–P(SiMe3)2 the
P–P bond was split [24]. So we used a mixture consisting of
Ph2P–P(SiMe3)Li, (Me3Si)2PLi and Ph2P–PPh2.
t
2.1. Reaction of Bu2P–P(SiMe3)Li with [Cp2ZrCl2]
t
Now we present the results of our studies on the reactivity of
A suspension of Bu2P–P(SiMe3)Liꢀ2THF (0.351 g, 0.878 mmol)
t
R2P–P(SiMe3)Li (R = iPr, Bu, Ph) towards [Cp2ZrCl2], [CpZrCl3] and
in pentane (2 mL) was slowly added to a suspension of [Cp2ZrCl2]
(0.232 g, 0.795 mmol) in pentane (3 mL) which was placed in a
cooling bath at ꢁ40 °C. The temperature of the reaction was main-
tained at ꢁ40 °C to ꢁ30 °C. The reaction mixture turned immedi-
ately violet. The resulting solution was stirred for 2 h at room
temperature, LiCl was filtered off and the solvent removed under
[Cp2HfCl2]. This work was presented in a preliminary form at the
18th International Conference on Phosphorus Chemistry [20].
⇑
Corresponding author. Tel.: +48 58 3472874.
E-mail address: jerzy.pikies@pg.gda.pl (J. Pikies).
0277-5387/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2011.01.031

R. Grubba et al. / Polyhedron 30 (2011) 1238–1243
1239
R
R
R
R
R
P
P2
R
R
P2
P1
R
P1 SiMe3
P1' SiMe3
Cp
Cp
P
Cp
Cp
Cp
Cp
Cp
Cp
M
M
M
SiMe3
M
P
R
R
Cl
Cl
P2'
R
R
Phosphido complexes
Phosphanylphosphido
complexes
Scheme 1.
PR2
P
PR2
[Cp2MCl2]
SiMe3
SiMe3
Cp
Cp
P
Cp
Cp
LiCl
M
SiMe3
M
P
PR2
Cl
R2P-P(SiMe3)Li
2, 4, 7
1, 3, 5, 6
1, 2 (M = Zr, R = tBu)
3, 4 (M = Zr, R = iPr)
5 (M = Hf, R = tBu)
6, 7 (M = Hf, R = iPr)
Scheme 2.
Ph
Ph
[Cp2ZrCl2]
P2
P(SiMe3)2
Cp
Cp
P1 SiMe3
LiCl
Zr
Cp
Zr
(Me3Si)2PLi
P(SiMe3)2
Cp
P3 SiMe3
SiMe3
Ph2P-P(SiMe3)Li
8
Scheme 3.
vacuum. The resulted [Cp2ZrCl{P1(SiMe3)–P2(tBu)2-
j
P1}] (1) is very
for 2 h at room temperature, LiCl was filtered off and the solvent
was removed under vacuum. The residue was dissolved in pentane
(1.5 mL) and after 1 week at room temperature small red needles
of 3 were deposited (0.050 g, yield 28%).
well soluble in hydrocarbons. After evaporation of pentane we ob-
tained a deep red oil. Attempts to obtain any crystals of 1 were
unsuccessful.
31P NMR (evacuated reaction solution, in toluene-d8): (1)
31P{1H} NMR (reaction solution in toluene, C6D6, ambient tem-
perature): (3) 35.1 ppm (d, P2), 2.9 ppm (d, P1), 1JP1–P2 = ꢁ427.5 Hz.
1
t
68.5 ppm (d, P2), ꢁ3.9 ppm (d, P1) JP1–P2 = ꢁ520.3 Hz; Bu2P–P(Si-
0
0
Me3)H [25], tBu2PH, and a small amount of P4(PtBu2)4 [26]. In some
Additionally: probably [Cp2Zr{P1,1 (SiMe3)–P2,2 iPr2}2] (4) 31.9 ppm
0
0
0
0
runs small resonances probably of [Cp2Zr{P1,1 (SiMe3)–P2,2 tBu2}2]
(d, P2,2 ); ꢁ94.9 ppm (d, P1,P1 ), JP1–P2 = ꢁ409.2 Hz, no features of
1
0
0
(2) were visible: 66.3 ppm (d, P2,2 ); ꢁ110.8 ppm (d, P1,1 ),
1JP1–P2 = ꢁ517.7 Hz. The signals display no features of an AA0XX0
spin pattern, however.1H NMR (evacuated reaction solution, in tol-
uene-d8): (1) 6.05 ppm (br.s, 11.1 H, C5H5) the expected two signals
an AA0XX0 pattern were visible; Pr2P2–P1(SiMe3)H ꢁ8.6 ppm (d,
i
P2), ꢁ201.6 ppm (d, P1), JP–P = ꢁ188.2 Hz, JP–H ꢂ 190 Hz; Pr2P–
1
1
i
i
1
t
P(SiMe3)2 [23]; Pr2PH ꢁ15.4 (s, JP–H ꢂ 191 Hz) and Pr2P2–P1H–
PiPr2: ꢁ2.6 ppm (d, P2), ꢁ140.0 ppm (t, P1), JP–P = ꢁ199.0 Hz,
1
3
are not resolved; 1.34 ppm (d, JPH 11.96 Hz, 19.3 H, C(CH3)3);
1JP–H ꢂ 190 Hz.
3
0.56 ppm (br. d, JPH 4.15 Hz, 9H, Si(CH3)3).
31P{1H} NMR (C6D6, ambient temperature): (3) 35.1 ppm (d, P2),
2.9 ppm (d, P1), JP1–P2 = ꢁ427.5 Hz.
1
i
2.1.1. Reaction of Pr2P–P(SiMe3)Li with [Cp2ZrCl2], synthesis of
1H NMR (C6D6, ambient temperature): (3) 6.061 ppm (s, 4.5H,
C5H5), 6.058 ppm (s, 4.6H, C5H5), 2.18 ppm (quart, quart, d, d,
[Cp2Zr(Cl){P(SiMe3)-PiPr2-
j
P1}] (3)
i
2
2
3
A solution of Pr2P–P(SiMe3)Liꢀ2.7THF (0.159 g, 0.377 mmol) in
toluene (2 mL) was slowly added to a suspension of [Cp2ZrCl2]
(0.109 g, 0.373 mmol) in toluene (2 mL) which was placed in a
cooling bath at ꢁ40 °C to ꢁ30 °C. The reaction mixture turned
immediately bright red. Then the resulting solution was stirred
2JHH 6.96 Hz, JHH 6.83 Hz, JPH 6.30 Hz, JPH 4.23 Hz, 2.0H,
2
3
(CH3)2CH), 1.36 ppm (dd, JHH 6.96 Hz, JPH 13.54 Hz, 11.7H (broad
signal under the multiplet), (CH3)2CH), 1.25 ppm (ddd, JHH
6.83 Hz, JPH 15.89 Hz, JPH 0.8 Hz, 7.0H, (CH3)2CH), 0.54 ppm (d,
2
3
4
3JPH 4.26 Hz, 9H, (CH3)3Si).

1240
R. Grubba et al. / Polyhedron 30 (2011) 1238–1243
Fig. 1. Molecular structure of
3 showing the atom-numbering scheme (30%
probability displacement ellipsoids), important bond lengths (pm) and bond angles
(°). H atoms have been omitted. Zr1–Cl1 247.4(1), Zr1–P1 258.3(1), P1–P2 218.7(2),
P1–Si1 225.4(2), P1–Zr1–Cl1 100.56(4), Zr1–P1–P2 117.56(5).
Fig. 3. Molecular structure of
probability displacement ellipsoids), important bond lengths (pm) and bond angles
(°). atoms have been omitted. C11–P3 183.8(4); C17–P3 188.5(5); Cl1–Zr1
9 showing the atom-numbering scheme (30%
H
252.3(1); Cl1–Li1 259.7(8); Cl2–Li1 250,1(8); Cl2–Zr1 252.7(1); Cl3–Zr1 263.6(1);
Cl3–Zr2 264.0(1); Cl4–Zr2 248,8(1); Cl5–Zr2 244.8(1); Li1–O1 195.5(9); Li1–O2
203.3(9); Li1–O3 206.7(10); P1–P2 218.6(2); P1–Si 225,5(2); P1–Zr2 267.9(1); P1–
Zr1 267.8(1); P2–P3 218.1(2); P2–Zr1 266.3(1); C17–P3–C11 101.8(2); C17–P3–P2
106.5(1); C11–P3–P2 105.1(1); P1–P2–P3 88.70(6); P3–P2–Zr1 104.65(6); Zr2–P1–
Zr1 102.67(4); P2–P1–Si1 108.59(7); Zr1–Cl3–Zr2 104.87(4).
well soluble in hydrocarbons and thus the attempts to obtain any
crystals of 5 were unsuccessful. After evaporation of pentane we
obtained a red-violet oil.
31P NMR (reaction solution, toluene, C6D6): (5) 67.5 ppm (d, P2),
1
ꢁ44.5 ppm (d, P1), JP1–P2 = ꢁ511.5 Hz; additionally tBu2P–P(Si-
t
Me3)H, Bu2P–P(SiMe3)2 and a small amount of two unidentified
compounds.
1H NMR (reaction solution, toluene, C6D6): (5) 6.03 ppm (br. s,
10.3H, C5H5) the expected two signals are not resolved; 1.39 ppm
3
3
(d, JPH 12.1 Hz, 20.2H, C(CH3)3); 0.60 ppm (br. d, JPH 3.74 Hz,
9H, Si(CH3)3).
i
2.1.3. Reaction of Pr2P–P(SiMe3)Li with [Cp2HfCl2], synthesis of
[Cp2Hf(Cl){P(SiMe3)-PiPr2- P1}] (6)
j
Fig. 2. Molecular structure of
6 showing the atom-numbering scheme (30%
A suspension of [Cp2HfCl2] (0.124 g, 0.327 mmol) in toluene
(2 mL) was slowly added to a solution of Pr2P–P(SiMe3)Liꢀ3THF
probability displacement ellipsoids), important bond lengths (pm) and bond angles
(°). H atoms have been omitted. Hf1–Cl1 244.83(9), Hf1–P1 256.81(9), P1–P2
218.5(1), P1–Si1 225.2(1), P1–Hf1–Cl1 100.30(3), Hf1–P1–P2 117.16(4).
i
(0.145 g, 0.327 mmol) in toluene (2 mL) which was placed in a
cooling bath at ꢁ40 °C. The temperature of the reaction was main-
tained at ꢁ40 °C to ꢁ30 °C. The reaction mixture turned slowly yel-
low. The resulting solution was stirred overnight at room
temperature and turned orange. Then the solvent was removed un-
der vacuum, the residue was dissolved in pentane (4 mL), LiCl was
filtered off and the solution was concentrated to 1 mL. After 3 days
at ꢁ35 °C yellow crystals of 6 were deposited (0.055 g, yield 30.2%).
31P{1H} NMR (reaction solution, toluene, C6D6): (6) 35.8 ppm (d,
13C{1H} NMR (C6D6, ambient temperature): (3) 112.45 ppm (s,
C5H5), 112.41 ppm (s, C5H5), 29.0 ppm (dd, 3.5 Hz, 21.9 Hz
(CH3)2CH), 24.3 ppm (dd, 5.3 Hz, 12.5 Hz (CH3)2CH), 24.1 ppm
(dd, 5.8 Hz, 22.5 Hz (CH3)2CH)), 6.70 ppm (d, 8.6 Hz (CH3)3Si).
Elemental analysis of (3): Anal. Calc. for C19H33P2ZrSiCl: C,
47.72; H, 6.96. Found: C, 47.74; H, 6.40%.
1
P2), ꢁ26.0 ppm (d, P1), JP1–P2 = ꢁ423.2 Hz; probably [Cp2Hf-
0
0
0
t
2.1.2. Reaction of Bu2P–P(SiMe3)Li with [Cp2HfCl2]
{P1,1 (SiMe3)–P2,2 iPr2}2] (7) (small amount), 31.1 ppm (d, P2,2 ),
0
1
i
i
A suspension of [Cp2HfCl2] (0.123 g, 0.313 mmol) in toluene
ꢁ114.8 ppm (d, P1,1 ), JP1–P2 = ꢁ410.5 Hz; Pr2P–P(SiMe3)H, Pr2P–
t
i
t
(2 mL) was slowly added to a solution of Bu2P–P(SiMe3)Liꢀ2THF
P(SiMe3)2 [24], Pr2PH and Pr2P–PH–PiPr2.
(0.148 g, 0.314 mmol) in toluene (2 mL) which was placed in a
cooling bath at ꢁ40 °C to ꢁ30 °C. The reaction mixture turned
slowly orange. After adding the suspension of [Cp2HfCl2] the
resulting slurry was stirred overnight at room temperature and
turned dark red. After that the solvent was removed under vac-
uum, the residue was dissolved in pentane (4 mL) and LiCl was fil-
1H NMR (reaction solution, toluene, C6D6): (6) 5.985 ppm (s,
4.8H, C5H5), 5.980 ppm (s, 4.7H, C5H5), 2.19 ppm (quart, quart, d,
2
2
2
3
d, JHH 6.98 Hz, JHH 6.83 Hz, JPH 6.90 Hz, JPH 4.23 Hz, (CH3)2CH,
2
3
partly hidden by solvent peak), 1.37 ppm (dd, JHH 6.98 Hz, JPH
13.54 Hz, 6.9H, (CH3)2CH)), 1.27 ppm (ddd, 2JHH 6.83,
3JPH 15.89 Hz, JPH 0.95 Hz, 7.7H, (CH3)2CH)), 0.56 ppm (d, JPH
4
3
tered off. The resulted [Cp2HfCl{P(SiMe3)–PtBu2- P1}] (5) is very
j
4.20 Hz, 9H, (CH3)3Si).

R. Grubba et al. / Polyhedron 30 (2011) 1238–1243
1241
2.1.4. Reaction of Ph2P–P(SiMe3)Li and (Me3Si)2PLiꢀ3THF with
[Cp2ZrCl2]
times Ueq for CH2 and CH groups. Solutions and refinements were
carried out using the SHELX-97 program package [31].
A suspension of 0.441 g of a mixture consisting of Ph2P–P(Si-
Me3)Liꢀ3THF (0.172 g, 0.336 mmol), (Me3Si)2PLiꢀ3THF (0.225 g,
0.563 mmol) and Ph2P–PPh2 (0.044 g, 0.118 mmol) in pentane
(3 mL) was slowly added to a suspension of [Cp2ZrCl2] (0.180 g,
0.617 mmol) in pentane (3 mL) which was placed in a cooling bath
at ꢁ40 °C to ꢁ30 °C. The reaction mixture turned immediately vio-
let. The resulting solution was stirred for 2 h at room temperature,
LiCl was filtered off and the solvent was partially removed under
vacuum. The concentrated solution was stored for two days at
ꢁ70 °C and an amorphous solid of unknown composition depos-
ited (the 31P NMR examination excluded 8).
3. Results and discussion
3.1. Reactivity
The addition of 1 equiv. of R2P–P(SiMe3)Li (R = iPr or tBu) to zir-
conocene dichloride or to hafnocene dichloride, respectively, in tol-
uene or pentane leads to coloured solutions containing presumably
the monosubstituted derivatives [Cp2M(Cl){P(SiMe3)–PR2-
(M = Zr or Hf) (compounds 1, 3, 5, 6) and small amounts of the
j
P1}]
31P NMR (reaction solution, pentane, C6D6): (8) 1.6 ppm (dd, P2),
disubstituted derivatives [Cp2M{P(SiMe3)–PR2-
2, 4, 7) (Scheme 2).
j
P1}2] (compounds
1
ꢁ42.1 ppm (dd, P3), ꢁ46.2 ppm (dd, P1), JP1–P2 = ꢁ376.0 Hz,
3
2JP1–P3 = 13.1 Hz, JP2–P3 = 8.7 Hz; additionally [Cp2Zr{P(SiMe3)2}2]
The reactivity of zirconocene dichloride towards R2P–P(SiMe3)Li
is much higher compared to hafnocene dichloride. The sterical ef-
fects of cyclopentadienyl rings are important, R2P–P(SiMe3)Li does
not react at ambient temperature with [Cp⁄2MCl2] (Cp⁄ = C5Me5,
M = Zr, Hf).
(strong signal), ꢁ72.0 ppm (s) [27]; small amounts of Ph2PSiMe3
ꢁ56.6 ppm (s) [28]; Ph2P–PPh2 ꢁ16.0 ppm (s) [28]; Ph2PH
ꢁ40.3 ppm (s) [29].
The reactions involving Ph2P–P(SiMe3)Li are considerably more
complex because of a significant amount of (Me3Si)2PLi in the re-
agent which we have used [24] and because the P–P bond in
Ph2P–P(SiMe3)Li is prone to fission reactions. The outcomes of a
reaction of [Cp2ZrCl2] with a mixture of Ph2P–P(SiMe3)Li and
(Me3Si)2PLi are shown in Scheme 3.
All these compounds are very well soluble in hydrocarbons. We
were able to isolate only compounds 3 and 6. Additionally, the con-
tents of compounds 2, 4 and 7 in the reaction solutions are low.
These compounds are very sensitive to moisture and oxygen. Com-
pound 3 is relatively stable and can be observed for several days in
the reaction solutions in sealed NMR tubes at ambient temperature
but attempts to dissolve 6 in C6D6 or in pentane lead to its almost
complete decomposition and to formation of white polymeric
materials.
2.1.5. Reaction of Ph2P–P(SiMe3)Li and (Me3Si)2PLi with [CpZrCl3],
synthesis of [Cp2Zr2Cl5(Ph2PPPSiMe3)(LiꢀTHFꢀDME)] (9)
A suspension of 0.249 g of a mixture consisting of Ph2P–P(Si-
Me3)Liꢀ3THF (0.097 g, 0.190 mmol), (Me3Si)2PLiꢀ3THF (0.127 g,
0.317 mmol) and Ph2P–PPh2 (0.025 g, 0.067 mmol) in toluene
(2 mL) was slowly added to
a
suspension of [CpZrCl3ꢀDME]
(0.178 g, 0.505 mmol) in toluene (2 mL) which was placed in a
cooling bath at ꢁ40 °C to ꢁ30 °C. The reaction mixture turned
immediately deep red. The resulting solution was warmed to room
temperature and filtered. The filtrate was reduced to its half vol-
ume and stored at ambient temperature. After several days a small
amount of red crystals of 9 deposited.
31P NMR (reaction solution, toluene, C6D6): (9) ꢁ15.0 ppm (dd,
P3), ꢁ77.7 ppm (dd, P2); ꢁ118.0 ppm (dd, P1), JP2–P3 = ꢁ228.5 Hz,
1
1JP1–P2 = ꢁ197.8 Hz, 2JP1–P3 = 19.1 Hz; additionally Ph2P–PPh2;
The isolation of compound 9 with the new triphosphorus ligand
Ph2PSiMe3; P(SiMe3)3; P(SiMe3)2H; Ph2P–P(SiMe3)2 [24].
Ph2P–P–P(SiMe3) in
a
reaction of Ph2P–P(SiMe3)Liꢀ3THF and
(Me3Si)2PLiꢀ3THF with a suspension of [CpZrCl3ꢀDME] indicates
the formation of a new P–P bond in the coordination sphere of a
Zr(IV) atom (Scheme 4).
2.1.6. X-ray diffraction
Experimental diffraction data were collected on a KM4CCD kap-
pa-geometry diffractometer, equipped with
a Sapphire2 CCD
The mechanism of the formation of 9 is not clear. We exclude an
intermediate with a Ph2P–PLi- group on the Zr atom because the
lithiation of a P–SiMe3 moiety is only possible in donor solvents
[19]. Ph2P–P(SiMe3)Li is not stable, but we have found no traces
of a triphosphane formation in a sample containing Ph2P–P(Li)-
SiMe3 and (Me3Si)2PLi in C6D6 at ambient temperature.
detector. An enhanced X-ray Mo K radiation source with a graph-
a
ite monochromator was used. Determination of the unit cells and
data collection were carried out at 150 and 120 K. Data reduction,
absorption correction, space group determination, solution and
refinement were made using the CRYSALIS software package (Oxford
Diffraction, 2008) [30].
Structures of 3, 6 and 9 were solved by direct methods and all
non-hydrogen atoms were refined with anisotropic thermal
parameters by full-matrix least squares procedures based on F2.
All hydrogen atoms were refined using an isotropic model with
Uiso(H) values fixed to be 1.5 times Ueq of C atoms for CH3 or 1.2
3.2. X-ray crystallographic studies of 3, 6 and 9
The crystal data and details of the data collection and refine-
ment for 3, 6 and 9 are given in Table 1.
Ph
Ph
Ph2P-P(SiMe3)2
P3
Cl
Cl
Cp
[CpZrCl3 · DME]
P2
Zr
Cl
P1
Ph2PSiMe3
P(SiMe3)3
Zr
Cp
Cl
Cl Li
(Me3Si)2PLi · 3THF
O
SiMe3
Ph2P-P(SiMe3)Li · 3THF
O
LiCl
O
9
Scheme 4.

1242
R. Grubba et al. / Polyhedron 30 (2011) 1238–1243
Table 1
Crystallographic data and structure refinement details for 3, 6 and 9.
Compound
(3)
(6)
(9)
Empirical formula
C
19H33ClZrP2Si
C19H33ClHfP2Si
565.42
120(2)
0.71073 (Mo K
monoclinic
P21/c
7.58010(10)
17.4850(3)
18.1108(4)
90.0
109.142(2)
90.0
2267.65(7)
4
1.656
1120
C33H47Cl5LiO3Zr2P3Si
478.15
120(2)
Mr (g molꢁ1
)
478.15
120(2)
0.71073 (Mo K
monoclinic
P21/c
7.5665(10)
17.518(3)
18.170(4)
90.0
109.267(14)
90.0
2273.5(7)
4
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
a)
a)
0.71073 (Mo K
a)
triclinic
ꢀ
P1
13.5652(6)
21.4372(10)
21.9544(14)
90.568(4)
91.132(5)
99.627(4)
6292.6(6)
6
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (mg mꢁ3
F(0 0 0)
)
1.397
992
0.795
1.551
2976
0.990
Absorption coefficient (mmꢁ1
Crystal size (mm)
h Range (°)
)
4.912
0.28 ꢃ 0.14 ꢃ 0.08
0.37 ꢃ 0.12 ꢃ 0.07
0.22 ꢃ 0.18 ꢃ 0.12
2.61–26.0
2.38–25.50
2.43–25.50
Limiting indices
ꢁ9 6 h 6 9
ꢁ7 6 h 6 9
ꢁ16 6 h 6 16
ꢁ21 6 k 6 20
ꢁ20 6 k 6 21
ꢁ25 6 k 6 25
ꢁ22 6 l 6 22
ꢁ21 6 l 6 18
ꢁ26 6 l 6 20
Reflections collected/unique
Completeness to hmax (%)
Refinement method
15435/4480 [Rint = 0.0553]
100.0
16001/4215 [Rint = 0.0246]
100.0
44649/23354 [Rint = 0.0453]
99.7
Full-matrix least-squares on F2
4480/0/224
Full-matrix least-squares on F2
4215/0/224
Full-matrix least-squares on F2
23354/0/1312
Data/restraints/parameters
Goodness-of-fit on F2
1.167
1.223
1.083
Final R indices [I > 2
R indices (all data)
r
(I)]
R1 = 0.0525, wR2 = 0.1163
R1 = 0.0597 wR2 = 0.1213
0.845 and ꢁ0.458
R1 = 0.0221, wR2 = 0.0597
R1 = 0.0258 wR2 = 0.0683
1.816 and ꢁ0.952
R1 = 0.0563, wR2 = 0.1257
R1 = 0.0597 wR2 = 0.1342
1.236 and ꢁ0.522
Largest difference in peak and hole (e Åꢁ3
)
Fig. 1 shows the molecular structure with thermal ellipsoids for
3, Fig. 2 shows the molecular structure with thermal ellipsoids for
6. The complexes 3 and 6 are isostructural and isotypic. Both 3 and
6 contain the metal atoms in highly distorted pseudotetrahedral
geometries. The angle between Zr, the centre of Cp1 and the centre
of Cp2 is 130.11°. Similarly the angle between Hf, the centre of Cp1
and the centre of Cp2 is 130.06°. The angle P1–Zr1–Cl1 is
100.56(4)° and the angle Cl1–Hf1–P1 is 100.30(3)°. The distances
Zr1–P1 of 258.3(1) pm and Hf1–P1 of 256.81(9) pm indicate the
partial double bond character of the Zr1–P1 and Hf–P1 bonds.
The angle Zr1–P1–P2 is 117.56(5)° and Hf1–P1–P2 is 117.16(4).
The relatively short P1–P2 distances (218.7(2) pm in 3 and
218.5(1) pm in 6) suggest a partial double bond character of this
bonds. In both compounds the geometries around P1 indicate a
high degree of planarity (the sum of angles around P1 is 348.57°
in 3 and 347.33° in 6) which is consistent with the short M–P1 dis-
tances. In spite of short P1–P2 distances the geometries around P2
are pyramidal (the sum of angles around P2 is 313.11° in 3 and
317.04° in 6).
ligand eliminates the
Hf–P1–P2 chain.
p-bonding participation in the bonds of the
Complex 9 (Fig. 3) includes three metal centres: two zirconium
atoms and one lithium atom. Both zirconium atoms possess dis-
torted octahedral geometry, each of them is bonded to a cyclopen-
tadienyl group, to three chloride atoms, and two phosphorus atoms
of the Ph2P3–P2–P1SiMe3 unit. In this ligand, the P1 atom coordi-
nates to both zirconium atoms, P2 coordinates only to Zr1, and P3
only to Zr2. The P–P distances in this ligand are very similar (aver-
age value 218.5 Å). This value suggests a partial double bond char-
acter of the P–P bonds in this moiety. The lithium atom is
surrounded by three oxygen atoms (one from a THF molecule
and two from a DME molecule) and two chloride atoms.
4. Conclusions
We introduce here the method for the synthesis of a new class
of transition metal complexes with diphosphorus ligands. In reac-
tions of Cp2MCl2 (M = Zr, Hf) with R2P–P(SiMe3)Li (R = tBu, Pr) in
i
The distances M–P1 in 3 and 6 are slightly longer than reported
for classical phosphido complexes of Zr(IV) and Hf(IV) with almost
planar geometry around the P atom, see [12–14]. For classical
phosphido complexes showing a more pyramidal geometry, longer
M–P distances than in 3 and 6 were reported [10,15,16]. The
toluene or pentane, the main products are phosphanylphosphido
complexes [Cp2M(Cl){P(SiMe3)–PR2-
phanylphosphido complexes [Cp2M{P(SiMe3)–PR2-
present in the reactions mixtures only in small amounts. In the
case of isopropyl derivatives, the solid state structures were inves-
tigated by X-ray diffraction. In a reaction of [CpZrCl3ꢀDME] with a
mixture of Ph2P–P(SiMe3)Liꢀ3THF and (Me3Si)2PLiꢀ3THF in toluene,
we observed the formation of a new P–P bond in the coordination
sphere of zirconium resulting in the triphosphorus ligand Ph2P–P–
PSiMe3 as part of a dinuclear Zr complex.
j
P1}]. Disubstituted phos-
j
P1}2] were
known X-ray structure of [Cp2Hf(Cl){P(SiMe3)–P(NEt2)2-j
P1}][19]
enables us to discuss a significant impact of the substituents bear-
ing nitrogen atoms in the phosphanyl group on the geometries of
the phosphanylphosphido complexes of hafnium(IV). The presence
of NEt2 groups increases the distance Hf–P1 from 256.81(9) pm in
6 to 264.8(4) pm in [Cp2Hf(Cl){P(SiMe3)–P(NEt2)2-
the distance P1–P2 from 218.5(1) pm in 6 to 224.0(5) pm in
[Cp2Hf(Cl){P(SiMe3)–P(NEt2)2-
P1}] and decreases the planarity
around P1. The sum of angles around P1 in 6 is 347.33° compared
to 322.71° in [Cp2Hf(Cl){P(SiMe3)–P(NEt2)2-
P1}]. Thus the pres-
ence of amino groups in the phosphanyl part of the R2P–P(SiMe3)
j
P1}], increases
j
Acknowledgements
j
J.P. and R.G. thank the Polish Ministry of Science and Higher
Education (Grant Nr. N N204 271535) for financial support.

R. Grubba et al. / Polyhedron 30 (2011) 1238–1243
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1243
Appendix A. Supplementary data
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107 (1985) 4670.
CCDC 797324, 787649, and 797323 contains the supplementary
crystallographic data for the structures of 3, 6 and 9. These data can
be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-
336-033; or e-mail: deposit@ccdc.cam.ac.uk.
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Soc., Chem. Commun. (2004) 2478.
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(2011) 2017.
[20] 18th International Conference on Phosphorus Chemistry, July 11–15. 2010,
Wroclaw, Poland, Book of Abstracts, p. 69.
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