Formation of polyphosphorus ligands mediated by zirconium and hafnium complexes

Article abstract of DOI:10.1016/j.poly.2013.02.046

The reactions of R₂P-P(SiMe₃)Li (R = ^tBu, ⁱPr, ⁱPr₂N) with [Cp₂MCl ₂] (M = Zr, Hf), [Cp*z.ast;CpZrCl₂] and [CpZrCl ₃] yielded polyphosphorus (mainly hexaphosphorus) compounds which can be viewed as intermediates between R₂P-P(SiMe₃)Li and derivatives of 1,2,3,4-tetraphosphabicyclo[1.1.0] butane. Thus R ₂P-P(SiMe₃)Li can act as a building block for the formation of the P₂ ligand and the R₂P-P(P₂) and R₂P-P(P₂)P-PR₂ moieties. Solid state structures of zirconium(IV) and hafnium(IV) complexes with R₂P- P(P₂) and R₂P-P(P₂)P-PR₂ ligands were established by X-ray studies.

Full text of DOI:10.1016/j.poly.2013.02.046

Polyhedron 55 (2013) 45–48
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Polyhedron
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Formation of polyphosphorus ligands mediated by zirconium
and hafnium complexes
a
b
a
a
´
Aleksandra Wisniewska , Agnieszka Łapczuk-Krygier , Katarzyna Baranowska , Jarosław Chojnacki ,
Eberhard Matern c, Jerzy Pikies a, Rafał Grubba a,
⇑
a Chemical Faculty, Department of Inorganic Chemistry, Gdansk University of Technology, G. Narutowicza St. 11/12, Pl-80-233 Gdansk, Poland
b Institute of Organic Chemistry and Technology, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland
c Institut für Anorganische Chemie, Universität Karlsruhe (TH), D-76128 Karlsruhe, Engesserstr. 15, Germany
a r t i c l e i n f o
a b s t r a c t
The reactions of R2P–P(SiMe3)Li (R = tBu, iPr, iPr2N) with [Cp2MCl2] (M = Zr, Hf), [Cp⁄CpZrCl2] and
[CpZrCl3] yielded polyphosphorus (mainly hexaphosphorus) compounds which can be viewed as inter-
mediates between R2P–P(SiMe3)Li and derivatives of 1,2,3,4-tetraphosphabicyclo[1.1.0] butane. Thus
R2P–P(SiMe3)Li can act as a building block for the formation of the P2 ligand and the R2P–P(P2) and
R2P–P(P2)P–PR2 moieties. Solid state structures of zirconium(IV) and hafnium(IV) complexes with R2P–
P(P2) and R2P–P(P2)P–PR2 ligands were established by X-ray studies.
Article history:
Received 17 October 2012
Accepted 12 February 2013
Available online 28 February 2013
Keywords:
P ligands
Polyphosphorus compounds
Zirconium
Ó 2013 Elsevier Ltd. All rights reserved.
Hafnium
1. Introduction
An overcrowding at the Zr center may induce P–C bond cleavage
in a PR ligand and therefore provide access to substituent free P-
The reactivity of lithium derivatives of diphosphanes, R2P–
complexes of Zr [8].
i
i
P(SiMe3)Li (R = tBu, Pr, Et2N and Pr2N), towards transition metal
complexes, [LnMCl2], has been the subject of our studies. Generally
this precursor in donor solvents can lead to phosphanylphosphi-
nidene (R2P–P) complexes. In the case of M = Zr and Cp
Now we present the results of our studies on the reactivity of
R2P–P(SiMe3)Li (R = tBu, iPr and iPr2N) towards [Cp2ZrCl2],
[CpZrCl3], [CpCp⁄ZrCl2] and [Cp2HfCl2] under conditions which lead
to polyphosphorus compounds. Some types (but not all) of our
polyphosphorus skeletons are obtainable via activation of white
phosphorus P4 mediated by early transition metal complexes, for
reviews see [9–11]. Thus the reactions involving R2P–P(SiMe3)Li
precursors can occur the usual way via P4 functionalization.
(g
5-C5H5) as a spectator ligand, these reactions lead to a terminal
t
complex with the Bu2P–P group or to dinuclear complexes with
this group in the side-on and terminal alignment [1]. The use of
(Et2N)2P–P(SiMe3)Li leads to the formation of the dimeric complex
[Cp2Zr{l-P–P(NEt2)2}2ZrCp2] with (Et2N)2P–P ligands in the bridg-
ing mode [2]. The introduction of spectator imido ligands results in
the formation of anionic tungsten(VI) complexes with a R2P@P
moiety in a side-on geometry [3]. Similarly the reactions of
[L2PtCl2] (L = tertiary phosphane) with R2P–P(SiMe3)Li yield Pt(0)
complexes with a side-on bonded R2P@P moiety [4]. The reactions
of these precursors depend very much on the sterical influence of
the spectator ligands. With small spectator ligands, such as Cp
and CpMe (CpMe = C5H4Me), these reactions give rise to phos-
phanylphosphido (R2P–PSiMe3) ligands [1–3,5,6]. If the spectator
ligands are of medium size (indenyl), the formed phos-
phanylphosphido complexes are overcrowded and probably un-
dergo a cleavage of the P–P bond in the ligand [7]. Stephan et al.
demonstrated a similar behaviour of phosphinidene complexes.
2. Experimental
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.
Literature methods were used to prepare R2P–P(SiMe3)LiꢀnL
i
(R = tBu, Pr, NiPr2; L = THF, DME) [12]. 31P NMR and 1H spectra
were recorded on Bruker AC250, Bruker AMX300 and Bruker
Av400 MHz spectrometers (external standard 85% H3PO4) at ambi-
ent temperature. Simulation of the spectra was performed with the
aid of BRUKER software [13]. Experimental diffraction data were col-
lected on a KM4CCD kappa-geometry diffractometer, equipped
⇑
with a Sapphire2 CCD detector. An enhanced X-ray Mo K
tion source with a graphite monochromator was used. Determina-
a radia-
Corresponding author. Tel.: +48 58 347 1714.
E-mail address: grubba@pg.gda.pl (R. Grubba).
0277-5387/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2013.02.046

´
A. Wisniewska et al. / Polyhedron 55 (2013) 45–48
46
tion of the unit cells and data collection were carried out at 150 or
120 K. Data reduction, absorption correction, space group determi-
nation, solution and refinement were made using the CRYSALISPRO
software package [14]. The structure of 5 was processed by the
SQUEEZE/PLATON program [15] to remove electron density of the disor-
dered solvent (ca. 74 eꢁ), equivalent to two molecules of THF (vol-
ume: 239 Å3).
t
2.1. Reaction of Bu2P–P(SiMe3)Li with [Cp2ZrCl2] and an excess of
PhPMe2
A solution of 0.411 g (1.028 mmol) tBu2P–P(SiMe3)Liꢀ2THF in
2 mL DME was added dropwise to a solution of 0.156 g (0.726 mmol)
[Cp2ZrCl2] and 0.7 mL PhPMe2 in 2 mL DME at ꢁ40 °C over 30 min.
The solution immediately turned deep red. The solution was left
for 6 h at ambient temperature and turned initially brown and then
green. The solvent was evaporated almost completely under re-
duced pressure and the residue was extracted with pentane
(2 mL). The extract was filtered; the volume was reduced to 1 mL un-
der reduced pressure and stored at room temperature. After 1 week,
Fig. 2. Molecular structure of
3 showing the atom-numbering scheme (50%
probability displacement ellipsoids), important bond lengths (Å) and bond angles
(°). H atoms have been omitted. Hf1–P2 2.631(2), Hf1–P3(no bond) 2.971(2) Hf1–P4
2.621(2), P1–P2 2.211(3), P2–P3 2.240(3), P3–P4 2.262(3), P2–Hf1–P4 89.23(7), P2–
P3–Hf2 114.3(1), P4–P3–Hf2 57.85(8), P3–P4–P5 108.4(1), Hf2–P5–P6 113.4(1), P4–
P5–P6 98.79(1).
deep blue–black crystals of [Cp2(PMe2Ph)Zr(g
1-P–PtBu2)] were
formed and separated. The mother liquor turned blue. After 1 month
at 4 °C, a small amount of yellow–green crystals of [{Zr(PPhMe2)-
Cp2}{cyclo-P3(PtBu2)}] (2) separated (0.030 g). In the mother liquor
we established the formation of 1.
turned orange. The solution was left at ambient temperature over-
night and turned deep red. The volatile compounds and the solvent
were evaporated under reduced pressure and the residue was ex-
tracted with 5 mL toluene. The extract was examined by 31P{1H},
31P and 1H NMR. The solution was then reduced to ꢂ1.5 mL and
stored at ꢁ30 °C. After 6 days deep red crystals of 3 formed
(0.028 g).
1
31P{1H} NMR (mother liquor), ppm: P4 183.9, P2 70.3, P1 16.5,
P5 5.92, P3 ꢁ150.4. JP1–P4 13.1 Hz, JP4–P5 27.9 Hz, JP3–P4 383.2 Hz,
JP1–P2 254.3 Hz, JP2–P3 99.2 Hz, JP1–P3 329.5 Hz, JP3–P5 7.6 Hz.
2
31P{1H} NMR (crystals dissolved in C6D6, for labelling of P
3
31P{1H} NMR (from mother liquor, for labelling of P atoms see
atoms see Fig. 1), ppm: P1 ꢁ181.9, P2 ꢁ200.7, P3 ꢁ138.4, P4
1
1
2
Fig. 2), ppm: AA0MM0XX00 P1, P6 42.4; P2, P5 19.4; P3, P4 ꢁ70.0;
75.2, P5 11.6. JP1–P2 300.7 Hz, JP1–P3 201.3 Hz, JP1–P4 52.9 Hz,
2
3
4
1JP1–P2 ꢁ225.5 Hz, JP1–P3 127.5 Hz, JP1–P4 9.7 Hz, JP1–P5 5.9 Hz,
2JP1–P5 10.7 Hz, JP2–P3 185.3 Hz, JP2–P4 64.8 Hz, JP2–P5 43.1 Hz,
1
2
2
5JP1–P6 3.3 Hz, JP2–P3 ꢁ265.2 Hz, JP2–P4 ꢁ2.5 Hz, JP2–P5 ꢁ3.5 Hz,
1
2
3
1JP3–P4 255.6 Hz, JP3–P5 19.3 Hz, JP4–P5 4.6 Hz.
3
4
4JP2–P6 5.9 Hz, JP3–P4 ꢁ341.9 Hz.
1
Additionally two unknown compounds, 3a and 3b, and several
i
2.2. Reaction of Pr2P–P(SiMe3)Li with [Cp2HfCl2] in THF
known compounds were found.
1
3a 31P{1H} NMR, ppm: P1 35.7, P2 ꢁ29.8, JP1–P2 ꢁ422.6 Hz. 3b
A solution of 0.121 g (0.828 mmol) [Cp2HfCl2] in 5 mL THF was
added dropwise to a solution of 0.457 g (0.828 mmol) iPr2P–
P(SiMe3)Liꢀ2.6THF in 2 mL THF at ꢁ40 °C. The resulting solution
31P{1H} NMR, ppm: P1 31.1, P2 ꢁ114.7, JP1–P2 ꢁ410.5 Hz. Known
1
compounds: iPr2P–P(SiMe3)2, iPr2P–P(SiMe3)H, iPr2P–PH–PiPr2,
iPr2PH.
t
2.3. Reaction of Bu2P–P(SiMe3)Li with [Cp⁄CpZrCl2] in THF
A solution of 0.186 g (0.492 mmol) [Cp⁄CpZrCl2] in 5 mL THF
t
was added dropwise to a solution of 0.361 g (0.972 mmol) Bu2P–
P(SiMe3)Liꢀ2THF in 3 mL THF at ꢁ70 °C over 1 h. The solution
immediately turned deep red. The solution was left overnight at
ambient temperature. The solvent was then evaporated under re-
duced pressure to dryness and the residue was extracted with pen-
tane (5 mL). The extract was filtered; the volume was reduced to
ꢂ2 mL under reduced pressure and stored at ꢁ70 °C. After
1 month, a small amount of red crystals of 4 precipitated (0.040 g).
4
31P{1H} NMR (mother liquor, see Fig. 3 for labelling), ppm:
P1 73.33, P2 53.78, P3 ꢁ201.83, P4 ꢁ97.12, P5 68.70, P6 79.32,
JP1–P2 10.45 Hz, JP1–P3 ꢁ306.80 Hz, JP1–P4 121.92 Hz, JP1–P5
ꢁ232.90 Hz, JP1–P6 1.96 Hz, JP2–P3 ꢁ264.01 Hz, JP2–P4 ꢁ188.35 Hz,
JP2–P5 5.75 Hz, JP2–P6 47.98 Hz, JP3–P4 ꢁ158.94 Hz, JP3–P5 126.61 Hz,
JP3–P6 133.60 Hz, JP4–P5 ꢁ4.55 Hz, JP4–P6 ꢁ232.60 Hz, JP5–P6 0.05 Hz.
2.4. Reaction of (iPr2N)2P–P(SiMe3)Li with [Cp⁄CpZrCl2] in THF
Fig. 1. Molecular structure of
probability displacement ellipsoids), important bond lengths (Å) and bond angles
(°). atoms have been omitted. Zr1–P1 2.7337(4), Zr1–P2 2.6862(7), Zr1–P5
2.7561(7), P1–P2 2.1596(10), P1–P3 2.2177(9), P2–P3 2.2026(10), P3–P4 2.2390(9),
P1–Zr–P2 46.96(4), P1–P3–P4 98.43(4), P2–P3–P4 100.09(4), P1–P3–P2 58.49(3),
C11–P4–P3 102.70(9), C15–P4–P3 99.24(9), C11–P4–C15 109.60(12), C11–P4–
P3 102.70(9), P3–P1–P2–Zr1 108.47(3).
2 showing the atom-numbering scheme (50%
A solution of 0.187 g (0.508 mmol) [Cp⁄CpZrCl2] in 4 mL THF
was added dropwise to a solution of 0.521 g (0.998 mmol) (iPr2N)2-
P–P(SiMe3)Liꢀ2.5ꢀTHF in 3 mL THF at ꢁ70 °C over 1 h. The solution
immediately turned orange. The solution was left for 2 days at
H

´
47
A. Wisniewska et al. / Polyhedron 55 (2013) 45–48
ꢀ
The X-ray structural investigation of 2 (triclinic, P1 group, Z = 2)
indicates a relatively short P1–P2 bond (2.1596 Å), which can be
explained as a double P–P bond coordinated side-on to the Zr cen-
ter. The P3–P1 (2.2173 Å) and P3–P2 (2.2026 Å) bond lengths are in
the range for P–P single bonds. P3–P4 (2.2390 Å) is slightly longer.
The geometry around the Zr1 atom is typical for a bent [Cp2ZrL3]
system [16], which forces Zr and the ligand atoms P1, P2 and P5
to lie in a common plane. The angle between the planes P1–P2–
P3 and P1–P2–Zr1 is 108.47°. The spatial alignment of these two
planes and the P–P distances in the P1–P2–P3–P4 fragment closely
resemble that of 2,4-bis[bis(diisopropylamino)phosphanyl]-
1,2,3,4-tetraphosphabicyclo[1.1.0]butane, with a similarly short
P1–P2 distance of 2.1610 Å [17]. According to isolobal relation-
ships [18], the metal fragment ZrCp2(PhPMe2), (d2ML7) can be re-
garded as replacing a phosphinidene fragment. Thus 2 can be
treated as an isolobal analogue of an 1,2,3,4-tetraphosphabicy-
clo[1.1.0] butane derivative. The 31P NMR data of 2 (first order spin
system) clearly support the similarity of these two skeletons. For
2:, the P2, P3 and P4 peaks are at ꢁ200.7, ꢁ138.4 and 75.2 ppm,
Fig. 3. Molecular structure of
4 showing the atom-numbering scheme (50%
probability displacement ellipsoids), important bond lengths (Å) and bond angles
(°). H atoms have been omitted. Zr1–P1 2.642(1), Zr1–P2 2.622(2), P1–P3 2.231(2),
P1–P5 2.237(2), P2–P3 2.226(2), P2–P4 2.195(2), P3–P4 2.205(2), P4–P6 2.231(2),
P1–Zr1–P2 90.37(5), P3–P1–Zr1 76.20(6), P3–P1–P5 96.41(8), P5–P1–Zr1 120.01(7),
P3–P2–Zr1 76.71(6), P4–P2–Zr1 95.73(7), P3–P2–P4 59.85(7), P1–P3–P2 113.83(9),
P1–P3–P4 101.86(8), P2–P4–P3 60.77(7), P2–P4–P6 104.78(8), P3–P4–P6 97.10(8).
respectively, whilst for (tBu2P–P)2( -P2) (AA0MM0X2 spin system)
l
the related values are ꢁ318.5, ꢁ141.4 and 65.0 ppm [19].
The mechanism for the formation of the P1–P4 part in the skel-
eton of 2 is not known. Generally two ways seem to be possible.
The first way may proceed via a formation of a P2 zirconium com-
plex as a result of a P–P bond cleavage in the tBu2P–P ligand (sim-
ilar to the P–C bond cleavage in the zirconium phosphinidene
ambient temperature and it turned brown. The solvent was then
evaporated under reduced pressure to dryness and the residue
was extracted with pentane (5 mL). The extract was filtered; the
volume was reduced to ꢂ2 mL under reduced pressure and stored
at 4 °C. After 3 weeks a small amount of red crystals of 5 precipi-
tated (0.020 g).
t
complexes [8]) followed by a Bu2P–P transfer. This assumption is
supported by the existence of a bridged complex, [(Cp⁄2Zr)2(
l-
P2)] [20], and by the ability of tBu2P–P(SiMe3)Li to form a bridging
P2 ligand [21].
The second way may formally be an insertion reaction of two P
atoms into a Zr–P bond in the terminal complex [Cp2(PhPMe2)-
Zr(g
1-P–PtBu2)]. The source of these P atoms is not known, but
3. Results and discussion
lithiated silyl derivatives of diphosphanes in polar solvents under-
go sequences of redistribution reactions forming phosphorus rich
compounds together with P(SiMe3)3 and (Me3Si)2PLi [22]. To the
best of our knowledge, the P skeleton of 2 is not accessible via reac-
tions of transition metal complexes with P4 [9–11].
The main reactions of R2P–P(SiMe3)Li (R = tBu, iPr and iPr2N) to-
wards [Cp2ZrCl2] and [Cp2HfCl2] leading to phosphanylphosphinid-
ene [1] and phosphanylphosphido complexes [1,2] are relatively
well understood. However, these reactions are accompanied by
some side processes:
i
The reaction of Pr2P–P(SiMe3)Li with [Cp2HfCl2] in THF yields
tBu2P–P(SiMe3)Li reacts with [Cp2ZrCl2] and an excess of PhPMe2
yielding mainly the known terminal phosphanylphosphinidene
several known compounds (iPr2P–P(SiMe3)2, iPr2P–P(SiMe3)H,
i
iPr2P–PH–PiPr2 and Pr2PH) and two unknown compounds 3a (2 P
complex [Cp2(PhPMe2)Zr(g
1-P–PtBu2)]. In some runs we observed,
atoms) and 3b (2 P atoms), together with 3 (see Section 2). Crystal-
lization of the reaction products from toluene solution yielded red
crystals of 3 (Fig. 2).
Compound 3 can formally be seen as the product of an insertion
of two [Cp2Hf] groups into the P–P bonds of the 2,4-bis[diisopro-
pylphosphanyl]-1,2,3,4-tetraphosphabicyclo[1.1.0]butane skele-
by 31P NMR, the formation of two additional pentaphosphorus com-
plexes 1 and 2 (Scheme 1) after 2 weeks in the reaction solution. So
far we have not been able to isolate 1. In solution it displays a
31P{1H} NMR first order spectrum (ppm): P4 183.9, P2 70.3, P1
16.5, P5 5.92, P3 ꢁ150.4, JP1–P4 13.1 Hz, JP4–P5 27.9 Hz,
JP3–P4 383.2 Hz, JP1–P2 254.3 Hz, JP2–P3 99.2 Hz, JP1–P3 329.5 Hz,
JP3–P5 7.6 Hz. An examination of the P–P coupling pattern suggests
ton.
3 (monoclinic, P21/n group, Z = 4) displays a distorted
tetrahedral geometry around the Hf atoms with a P2–Hf1–P4 angle
of 89.23°, typical for [Cp2HfL2] compounds [23]. All the P–P bond
lengths indicate their single bond character. All P atoms display a
pyramidal geometry, the sum of angles around the P atoms is
302.11, 281.69 and 299.50° for P1, P2 and P3, respectively.
31P NMR data of 3 in solution (AA’MM’XX’ spin system) support
t
that a Bu2P4–P3 bond and a P3–P1–P2 triangle are placed around
the ZrCp2(P5PhMe2) centre, but that only P4 and P3 couple with
P5PhMe2 (Scheme 1). Thus a skeleton similar to that of 2 is
probable.
Compound 2 was isolated from the mother liquor (pentane
solution) after isolation of [Cp2(PhPMe2)Zr(g
1-P–PtBu2)], and was
1
1
the XRD results. The coupling constants JP1–P2 ꢁ225.5 Hz, JP2–P3
ꢁ265.2 Hz and 1JP3–P4 ꢁ341.9 Hz indicate the single bond character
of the related bonds. Such a skeleton (with two early transition
metal centres) was not observed in the reactions of early transition
metal complexes with P4 [9–11].
characterized by XRD (Fig. 1) and its 31P NMR spectrum.
Cp
Cp
P5Me2Ph
Reactions of R2P–P(SiMe3)Li with [Cp⁄CpZrCl2] do not lead to
complexes with R2PP or R2PP(SiMe3) ligands, probably due to the
sterically demanding Cp⁄ groups. In the case of R = tBu, the mono-
nuclear P6 compound 4 (Fig. 3) was isolated in moderate yield. The
mother liquor additionally contained tBu2P–P(SiMe3)2, tBu2P–
Cp
Cp
P5Me2Ph
Zr
1
P1
P
tBu2P4
P3
Zr
tBu2P4
P3
P2
P2
2
1
t
t
P(SiMe3)H, Bu2P–PH–PtBu2, Bu2PH and P(SiMe3)3. In the case of
Scheme 1.
R = iPr2N, compound 5 (Fig. 4) was isolated, albeit in a low yield.

´
48
A. Wisniewska et al. / Polyhedron 55 (2013) 45–48
4. Conclusion
Our results prove that the formation of the 1,2,3,4-tetraphos-
phabicyclo[1.1.0] butane skeleton is probably thermodynamically
very favorable. It is formed either from molecules which contain
P–PR2 groups, such as tBu2P–P = P(Me) tBu2 [19] or R2P–P(SiMe3)Li,
or maybe via P4 functionalization as well. Thus the P–PR2 group can
act as a precursor for a P2 ligand [22] as well as for the R2P–P(P2)
moiety (compound 2), and for the R2P–P(P2)P–PR2 moiety (com-
pounds 3, 4, 5 and 6). The formation of the 1,2,3,4-tetraphosphab-
icyclo[1.1.0]butane skeleton results from a P–P bond splitting in
the P–PR2 group. The side products (especially the formation of a
large amount of (iPr2N)2P–P(NiPr2)2) support a radical mechanism
of these cleavages.
Acknowledgements
J.P. and R.G. thank the Polish Ministry of Science and Higher
Education (Grant No. N N204 271535) for financial support. A.Ł.-
K. thanks the Polish Ministry of Science and Higher Education
(Grant No. N N204 145038) for financial support.
Fig. 4. Molecular structure of
5 showing the atom-numbering scheme (50%
probability displacement ellipsoids), important bond lengths (Å) and bond angles
(°). H atoms have been omitted. Zr1–P1 2.624(1), Zr1–P2 2.630(1), P1–P3 2.243(1),
P1–P5 2.264(1), P2–P3 2.236(1), P2–P4 2.191(1), P3–P4 2.208(1), P4–P6 2.244(1),
P1–Zr1–P2 90.93(2), P3–P1–Zr1 77.02(3), P3–P1–P5 92.77(3), P5–P1–Zr1 117.00(3),
P3–P2–Zr1 77.01(3), P4–P2–Zr1 95.04(3), P3–P2–P4 59.82(3), P1–P3–P2 113.49(4),
P1–P3–P4 104.25(4), P2–P4–P3 61.07(3), P2–P4–P6 102.73(4), P3–P4–P6 98.16(4),
Appendix A. Supplementary data
N1–P5–P1
98.49(8),
N2–P5–P1 103.05(8),
N1–P5–N2 108.9(1),
N3–P6–
P4 101.34(8), N4–P6–P4 97.74(8), N3–P6–N4 109.8 (1).
CCDC 905598-905601 contains the supplementary crystallo-
graphic data for 2–5. 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, Cam-
bridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk.
P1
(iPr2N)2P
P
P
P(NiPr2)2
P2
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[2] R. Grubba, A. Wis´niewska, K. Baranowska, E. Matern, J. Pikies, Dalton Trans. 40
Scheme 2.
(2011) 2017.
[3] R. Grubba, K. Baranowska, J. Chojnacki, J. Pikies, Eur. J. Inorg. Chem. 20 (2012)
3263.
In the mother liquor we detected (iPr2N)2P–P(SiMe3), (iPr2N)2P–
P(SiMe3)H, P(SiMe3)2H, (iPr2N)2P–P(NiPr2)2 (strong singlet) and
P(SiMe3)3, together with small amounts of unknown polyphos-
phorus compounds.
´
[4] W. Domanska-Babul, J. Chojnacki, E. Matern, J. Pikies, Dalton Trans. (2009) 146.
[5] R. Grubba, A. Wis´niewska, K. Baranowska, E. Matern, J. Pikies, Polyhedron 30
(2011) 1238.
[6] a R. Grubba, K. Baranowska, D. Gudat, J. Pikies, Organometallics 30 (2011)
6655;
´
b T. Kruczynski, R. Grubba, K. Baranowska, J. Pikies, Polyhedron 39 (2012) 25.
A similar compound (R = SiMe3) was previously obtained in the
reaction of [Cp2Zr{P(SiMe3)2}2] with P4 [24]. The labelling of the P
atoms in 4 and 5 is the same as in [24].
[7] A. Łapczuk-Krygier, K. Baranowska, Ł. Ponikiewski, E. Matern, J. Pikies, Inorg.
Chim. Acta 387 (2012) 361.
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[11] B.M. Cossairt, N.A. Piro, C.C. Cummins, Chem. Rev. 110 (2010) 4164.
ꢀ
Compounds 4 (monoclinic, P21/c group, Z = 4), 5 (triclinic, P1
group, Z = 2) and 1,1,6,6-tetrakis(trimethylsilyl)(P2–P4)-hexaphos-
phane-P3,P5-zirconocene [24] display very similar spatial align-
ments. Both compounds 4 and 5 indicate a distorted tetrahedral
geometry around the Zr atoms with P1–Zr1–P2 angles of 90.37°
(for 4) and 90.93° (for 5). All the P atoms exhibit a pyramidal geom-
etry. The triangles P2,P3,P4 resemble the fragment of a P4 mole-
cule. 31P NMR data of 4 (first order spectrum) indicate that this
compound is identical in the solid state and in solution. Our results
prove that this unusually stable P1–P6 skeleton is formed not only
via splitting of a P–P bond in a P4 molecule but also via reactions of
molecules containing a P–PR2 moiety as well.
´
[12] W. Domanska-Babul, K. Baranowska, R. Grubba, E. Matern, J. Pikies,
Polyhedron 26 (2007) 5491.
[13] a Programs WINNMR and WINDAISY, Bruker Daltonik, Bremen, 1999.;
b G. Hägele, M. Engelhardt, W. Boenigk, Simulation und automatisierte
Analyse von NMR-Spektren, VCH, Weinheim, 1987.
[14] Program CRYSALISPRO
2008.
[15] Program package PLATON including the SQUEEZE procedure A.L. Spek, J. Appl.
Crystallogr. 36 (2003) 7.
[16] T.A. Albright, J.K. Burdett, M.-H. Whangbo, Orbital Interactions in Chemistry,
John Wiley & Sons, 1984. p. 349.
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o2427.
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[19] E. Matern, G. Fritz, J. Pikies, Z. Anorg. Allg. Chem. 623 (1997) 1769.
[20] M.C. Fermin, J. Ho, D.W. Stephan, J. Am. Chem. Soc. 116 (1994) 6033.
[21] W. Doman´ ska-Babul, J. Chojnacki, E. Matern, J. Pikies, J. Organomet. Chem. 692
(2007) 3640.
, Version 1.171, Oxford Diffraction, Abingdon, England,
[CpZrCl3] reacts with (iPr2N)2P–P(SiMe3)Li yielding a complex
mixture of polyphosphorus compounds. In the 31P NMR spectrum
of the mother liquor we found the P1,P2 signal of 6 [17] (Scheme 2),
together with the signals of (iPr2N)2P–P( 2-PNiPr2)2PSiMe3
l
[2], with strong signals of (iPr2N)2P–P(SiMe3)2, (iPr2N)2P–P(SiMe3)-
H, (iPr2N)2P–P(NiPr2)2 and (iPr2N)2PH.
[22] G. Fritz, K. Stoll, Z. Anorg. Allg. Chem. 538 (1986) 78.
[23] A. Wisniewska, K. Baranowska, J. Pikies, Acta Crystallogr., Sect. E63 (2007)
´
m2174.
Similar compounds were formed in the thermal rearrangement
of tBu2P–P = P(Me) tBu2 [19] and in the reaction of P4 with
(iPr2N){(Me3Si)2N}P–P{N(SiMe3)2}(NiPr2) [25].
[24] E. Hey, M.F. Lappert, J.L. Atwood, S.G. Bott, J. Chem. Soc., Chem. Commun.
(1987) 597.
[25] J.P. Bezombes, P.B. Hitchcock, M.F. Lappert, J.E. Nycz, Dalton Trans. (2004) 499.